TW201824222A - Manufacturing method of display device, display device, display module and electronic apparatus - Google Patents

Abstract

To provide a manufacturing method of a display device with low power consumption. A manufacturing method of a display device includes the steps of: forming a first common electrode on a first substrate; forming a resin layer with a thickness of 0.1 [mu]m to 3 [mu]m on the prepared substrate; forming a thin region on the resin layer; forming a first pixel electrode on the resin layer; forming a conductive layer covering a second region simultaneously with the step of forming the first pixel electrode; forming a first insulating layer on the first pixel electrode; forming a second display element on the insulating layer; bonding the prepared substrate to the second substrate using an adhesive; irradiating the resin layer with a laser beam; separating the prepared substrate from the first pixel electrode; disposing liquid crystal between the first common electrode and the first pixel electrode, and bonding the first substrate to the second substrate using an adhesive, thus forming a first display element.

Description

   Manufacturing method of display device, display device, display module and electronic device   

One embodiment of the present invention relates to a method for manufacturing a display device.

An embodiment of the present invention is not limited to the above technical field. The technical field of an embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, a product, or a composition of matter. Therefore, specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a liquid crystal display device, a light emitting device, a lighting device, a power storage device, a memory device, A method of driving these devices and a method of manufacturing these devices.

In recent years, display devices are expected to be applied to various applications. As the display device, for example, a light emitting device including a light emitting element, a liquid crystal display device including a liquid crystal element, and the like have been developed.

For example, Patent Document 1 discloses a flexible light-emitting device using an organic EL (Electroluminescence) element.

Patent Document 2 discloses a semi-transmissive liquid crystal display device including a region that reflects visible light and a region that transmits visible light. It can be used as a reflective liquid crystal display device in an environment where sufficient external light can be obtained. It can be used as a transmissive liquid crystal display device in an external light environment.

[Patent Document 1] Japanese Patent Application Publication No. 2014-197522

[Patent Document 2] Japanese Patent Application Laid-Open No. 2011-191750

An object of one embodiment of the present invention is to provide a method for manufacturing a display device with low power consumption. An object of one embodiment of the present invention is to provide a method for manufacturing a display device having high visibility regardless of surrounding brightness. An object of one embodiment of the present invention is to provide a method for manufacturing an all-weather display device. An object of one embodiment of the present invention is to provide a method for manufacturing a display device with high convenience. An object of one embodiment of the present invention is a method for manufacturing a display device that achieves a reduction in thickness or weight. In addition, an object of one embodiment of the present invention is to provide a simpler manufacturing method as described above.

Note that the recording of these purposes does not prevent the existence of other purposes. It is not necessary for one embodiment of the present invention to achieve all the above-mentioned objects. Objects other than those described above can be extracted from the description, drawings, and descriptions of the scope of patent applications.

An embodiment of the present invention is a method for manufacturing a display device, the display device including: a first display element; a second display element; a first insulating layer; and a conductive layer, the first display element includes: A first pixel electrode; a liquid crystal; and a first common electrode having a function of transmitting visible light; the second display element includes: a second pixel electrode having a function of transmitting visible light; a light emitting layer; and a second electrode having a function of reflecting visible light For the common electrode, the method includes the following steps: using a thermosetting material, forming a resin layer including a first region having a thickness of 0.1 μm or more and 3 μm or less and a second region having a thickness smaller than the first region on the manufacturing substrate; Step; forming a first region and a second region having a thickness smaller than the first region in the resin layer; forming a first pixel electrode on the resin layer; and simultaneously forming the first pixel electrode to cover the second region A step of forming a conductive layer in a region manner; a step of forming a first insulating layer on a first pixel electrode; A step of forming a second pixel electrode, a light-emitting layer, and a second common electrode in order to form a second display element; a step of bonding a manufacturing substrate and a second substrate using an adhesive; a step of irradiating a laser to a resin layer; A step of manufacturing a substrate separated from the first pixel electrode; and a step of disposing liquid crystal between the first common electrode and the first pixel electrode, and bonding the first substrate and the second substrate with an adhesive to form a first display element.

Another embodiment of the present invention is the method for manufacturing a display device described above, wherein in the step of separating the manufacturing substrate from the first pixel electrode, the interface between the resin layer and the manufacturing substrate is separated, and further comprising separating the conductive layer after the separation step. Exposed steps.

Another embodiment of the present invention is the method for manufacturing the display device described above, wherein in the step of separating the manufacturing substrate from the first pixel electrode, the separation is performed within the resin layer and between the manufacturing substrate and the pixel electrode and the conductive layer, and A step of exposing the conductive layer after the separation step is included.

Another embodiment of the present invention is the method for manufacturing the display device described above, and further includes a step of forming an insulating layer on the resin layer after forming the second region in the resin layer.

Another embodiment of the present invention is the method for manufacturing the display device described above, further comprising the step of forming an insulating layer on the resin layer after forming the second region in the resin layer, and in the step of separating the manufacturing substrate from the first pixel electrode, The separation is performed inside the resin layer and at the interface between the resin layer and the insulating layer, and further includes a step of exposing the conductive layer after the separation step.

Another embodiment of the present invention is the method for manufacturing a display device described above, wherein the material of the insulating layer is an inorganic insulating material.

Another embodiment of the present invention is the method of manufacturing the display device described above, wherein in the step of separating the manufacturing substrate from the first pixel electrode, the inside of the resin layer and the interface between the resin layer and the conductive layer are separated.

Another embodiment of the present invention is the method for manufacturing the display device described above, and further includes a step of connecting the wiring of the input signal or power to the exposed conductive layer through the connection layer.

Another embodiment of the present invention is the method of manufacturing the display device described above, wherein the exposed conductive layer is connected to the first common electrode through a connector.

Another embodiment of the present invention is the method for manufacturing a display device described above, wherein the resin layer is formed using a solution having a viscosity of 5 cP or more and less than 100 cP.

Another embodiment of the present invention is the method for manufacturing a display device described above, wherein the resin layer is formed using a solution having a viscosity of 10 cP or more and less than 50 cP.

Another embodiment of the present invention is the method for manufacturing a display device described above, wherein the resin layer is formed using a spin coater.

Another embodiment of the present invention is the method for manufacturing the display device described above, further comprising: forming an transistor including an oxide semiconductor in a channel formation region between the step of forming the first pixel electrode and the step of forming the second pixel electrode. A step in which the resin layer is heated at a temperature higher than the heating temperature in the step of forming the transistor, in the step of forming the resin layer.

Another embodiment of the present invention is the method for manufacturing a display device described above, wherein a material forming the resin layer is a material having photosensitivity.

According to one embodiment of the present invention, a method for manufacturing a display device with low power consumption can be provided. According to one embodiment of the present invention, it is possible to provide a method for manufacturing a display device having high visibility regardless of the surrounding brightness. According to one embodiment of the present invention, a method for manufacturing an all-weather display device can be provided. According to one embodiment of the present invention, a method for manufacturing a display device with high convenience can be provided. According to one embodiment of the present invention, it is possible to provide a method for manufacturing a display device that is thinner or lighter.

ANO‧‧‧Wiring

C1‧‧‧Capacitor

C2‧‧‧Capacitor

CSCOM‧‧‧Wiring

G1‧‧‧Wiring

G2‧‧‧Wiring

G3‧‧‧Wiring

GD‧‧‧Circuit

S1‧‧‧Wiring

S2‧‧‧Wiring

S3‧‧‧Wiring

SD‧‧‧Circuit

SW1‧‧‧Switch

SW2‧‧‧Switch

VCOM1‧‧‧Wiring

VCOM2‧‧‧Wiring

X1‧‧‧distance

X2‧‧‧distance

10‧‧‧ display device

14‧‧‧Display

21‧‧‧ Glow

22‧‧‧Reflected light

30‧‧‧pixel unit

31B‧‧‧First display element

31G‧‧‧The first display element

31p‧‧‧pixel

31R‧‧‧The first display element

31W‧‧‧First display element

32B‧‧‧Second Display Element

32G‧‧‧Second Display Element

32p‧‧‧pixel

32R‧‧‧Second Display Element

32W‧‧‧Second Display Element

32Y‧‧‧Second Display Element

35r‧‧‧light

35t‧‧‧light

35tr‧‧‧light

41‧‧‧ Transistor

42‧‧‧ Transistor

61‧‧‧Manufacture of substrates

62‧‧‧resin layer

63‧‧‧Insulation

100‧‧‧ display device

110a‧‧‧Transistor

110b‧‧‧Transistor

110c‧‧‧Transistor

110d‧‧‧Transistor

110e‧‧‧Transistor

110f‧‧‧ Transistor

110g‧‧‧Transistor

110h‧‧‧Transistor

112‧‧‧ LCD

113‧‧‧electrode

117‧‧‧ Insulation

121‧‧‧ Insulation

131‧‧‧color layer

132‧‧‧Light-shielding layer

133a‧‧‧Alignment film

133b‧‧‧Alignment film

134‧‧‧color layer

135‧‧‧polarizing plate

141‧‧‧adhesive layer

142‧‧‧Adhesive layer

151‧‧‧Insulation

170‧‧‧Light-emitting element

180‧‧‧LCD element

191‧‧‧electrode

192‧‧‧EL layer

193‧‧‧electrode

194‧‧‧Insulation

201‧‧‧ Transistors

203‧‧‧Transistor

204‧‧‧ Connection Department

205‧‧‧Transistor

206‧‧‧Transistor

207‧‧‧Connection Department

211‧‧‧insulation layer

212‧‧‧Insulation

213‧‧‧Insulation

214‧‧‧Insulation

216‧‧‧Insulation

217‧‧‧Insulation

218‧‧‧Insulation

220‧‧‧ Insulation

221‧‧‧ conductive layer

221a‧‧‧ conductive layer

221b‧‧‧ conductive layer

222a‧‧‧ conductive layer

222b‧‧‧ conductive layer

223‧‧‧ conductive layer

231‧‧‧Semiconductor layer

235‧‧‧ conductive layer

242‧‧‧ Connection layer

243‧‧‧Connector

252‧‧‧Connection Department

261‧‧‧Semiconductor layer

263a‧‧‧ conductive layer

263b‧‧‧ conductive layer

281‧‧‧Transistor

284‧‧‧Transistor

285‧‧‧Transistor

286‧‧‧Transistor

300‧‧‧ display device

300A‧‧‧ display device

300B‧‧‧ display device

300C‧‧‧Display Device

311‧‧‧electrode

311a‧‧‧electrode

311b‧‧‧electrode

311c‧‧‧ conductive layer

311d‧‧‧ conductive layer

311e‧‧‧ conductive layer

311f‧‧‧ conductive layer

340‧‧‧LCD element

351‧‧‧ substrate

360‧‧‧Light-emitting element

360b‧‧‧light-emitting element

360g‧‧‧Light-emitting element

360r‧‧‧Light-emitting element

360w‧‧‧light-emitting element

361‧‧‧ substrate

362‧‧‧Display

364‧‧‧Circuit

365‧‧‧Wiring

372‧‧‧FPC

373‧‧‧IC

400‧‧‧ display device

410‧‧‧ pixels

451‧‧‧ opening

800‧‧‧ Portable Information Terminal

801‧‧‧shell

802‧‧‧shell

803‧‧‧Display

804‧‧‧Display

805‧‧‧hinge section

810‧‧‧Portable Information Terminal

811‧‧‧shell

812‧‧‧Display

813‧‧‧Operation buttons

814‧‧‧External port

815‧‧‧Speaker

816‧‧‧Microphone

817‧‧‧ Camera

820‧‧‧ Camera

821‧‧‧Shell

822‧‧‧Display

823‧‧‧Operation buttons

824‧‧‧Shutter button

826‧‧‧Lens

8000‧‧‧ Display Module

8001‧‧‧ Upper cover

8002‧‧‧ Lower cover

8003‧‧‧FPC

8004‧‧‧Touch Panel

8005‧‧‧FPC

8006‧‧‧Display Panel

8009‧‧‧Frame

8010‧‧‧Printed Circuit Board

8011‧‧‧Battery

9000‧‧‧ shell

9001‧‧‧Display Department

9003‧‧‧ Speaker

9005‧‧‧ operation keys

9006‧‧‧Connection terminal

9007‧‧‧Sensor

9008‧‧‧ Microphone

9055‧‧‧ hinge

9200‧‧‧Portable Information Terminal

9201‧‧‧Portable Information Terminal

9202‧‧‧Portable Information Terminal

In the drawings: FIG. 1 is a sectional view showing an example of a display device; FIG. 2 is a sectional view showing an example of a display device; FIG. 3 is a sectional view showing an example of a display device; A perspective view showing an example of a display device; FIGS. 5A and 5B are cross-sectional views showing an example of a display device; FIGS. 6A to 6E are cross-sectional views showing an example of a transistor; FIGS. 7A to 7D 8A and 8B are cross-sectional views illustrating an example of a method for manufacturing a display device; and FIGS. 9A and 9B are cross-sectional views illustrating a method of manufacturing a display device. 10A and 10B are cross-sectional views illustrating an example of a method of manufacturing a display device; FIG. 11 is a cross-sectional view illustrating an example of a display device and an example of a method of manufacturing the display device; FIG. 12A 12D are sectional views showing an example of a manufacturing method of a display device; FIGS. 13A and 13B are sectional views showing an example of a manufacturing method of a display device; FIGS. 14A and 14B are views showing manufacturing of a display device; Method one Examples are sectional views; FIGS. 15A and 15B are sectional views showing an example of a manufacturing method of a display device; FIG. 16 is a sectional view showing an example of a manufacturing method of a display device; FIGS. 17A and 17B are views A cross-sectional view showing an example of a manufacturing method of a display device; FIG. 18 is a cross-sectional view showing an example of a display device and an example of a manufacturing method of the display device; and FIGS. 19A to 19D are views showing a method of manufacturing the display device. Examples are sectional views; FIGS. 20A and 20B are sectional views showing an example of a manufacturing method of a display device; FIGS. 21A and 21B are sectional views showing an example of a manufacturing method of a display device; FIGS. 22A and 22B FIG. 23 is a cross-sectional view showing an example of a display device manufacturing method; FIG. 23 is a cross-sectional view showing an example of a display device and an example of a manufacturing method of the display device; FIG. 24 is a block diagram showing an example of a display device 25A to 25C are diagrams showing an example of a pixel unit; FIGS. 26A to 26C are diagrams showing an example of a pixel unit; and FIGS. 27A to 27C are diagrams showing a pixel unit 28A, 28B1, 28B2, 28B3, and 28B4 are diagrams showing an example of a display device and an example of a pixel; FIG. 29 is a circuit diagram of an example of a pixel circuit of the display device; 30A and 30B are a circuit diagram showing an example of a pixel circuit of a display device and a diagram showing an example of a pixel; FIG. 31 is a diagram showing an example of a display module; and FIGS. 32A to 32D are diagrams showing electronics A diagram of an example of a device; FIGS. 33A to 33E are diagrams showing an example of an electronic device.

The embodiment will be described in detail with reference to the drawings. Note that the present invention is not limited to the following description, and a person of ordinary skill in the art can easily understand the fact that the manner and details can be changed into various kinds without departing from the spirit and scope of the present invention. form. Therefore, the present invention should not be construed as being limited to the content described in the embodiments shown below.

Note that in the invention structure described below, the same element symbols are commonly used in different drawings to represent the same parts or parts having the same functions, and repeated descriptions are omitted. In addition, the same hatching is sometimes used when representing parts having the same function, and no special symbol is attached.

In addition, for ease of understanding, the positions, sizes, and ranges of the components shown in the drawings may not indicate the actual positions, sizes, and ranges of the components. Therefore, the disclosed invention is not necessarily limited to the position, size, scope, etc. disclosed in the drawings.

In addition, depending on the situation or state, the "film" and "layer" can be interchanged with each other. For example, the "conductive layer" may sometimes be converted into a "conductive film". In addition, the "insulation film" may be converted into an "insulation layer" in some cases.

In this specification and the like, metal oxide refers to an oxide of a metal in a broad sense. Metal oxides are classified into oxide insulators, oxide conductors (including transparent oxide conductors), oxide semiconductors (also referred to as OS), and the like. For example, when a metal oxide is used for a semiconductor layer of a transistor, the metal oxide is sometimes referred to as an oxide semiconductor. In other words, the OS FET can be referred to as a transistor including a metal oxide or an oxide semiconductor.

In addition, in this specification and the like, a metal oxide containing nitrogen may also be referred to as a metal oxide. In addition, a metal oxide containing nitrogen may be referred to as a metal oxynitride.

In addition, in this specification and the like, CAAC (c-axis aligned crystal) or CAC (cloud-aligned composite) may be described. Note that CAAC is an example of a crystalline structure, and CAC is an example of a function or a material composition.

Next, an example of a crystal structure of an oxide semiconductor or a metal oxide will be described. Note that an oxide semiconductor formed by a sputtering method using an In-Ga-Zn oxide target (In: Ga: Zn = 4: 2: 4.1 [atomic number ratio]) will be described as an example. An oxide semiconductor formed by a sputtering method at a substrate temperature of 100 ° C. to 130 ° C. using the above target is called sIGZO, and the above target is used to sputter at a substrate temperature of room temperature (RT) by sputtering. The oxide semiconductor formed by this method is called tIGZO. For example, sIGZO has a crystal structure of one or both of nc (nano crystal) and CAAC. In addition, tIGZO has a crystal structure of nc. Note that the room temperature (R.T.) referred to herein includes a temperature when the substrate is not intentionally heated.

In this specification and the like, CAC-OS or CAC-metal oxide has a function of a conductor in one part of the material, a function of a dielectric (or insulator) in another part of the material, and a semiconductor as a whole of the material. Functions. In addition, when CAC-OS or CAC-metal oxide is used for a semiconductor layer of a transistor, a conductor has a function of passing electrons (or holes) used as a carrier, and a dielectric has a function of preventing Used as a function of carrier electron flow. The complementary function of the function of the conductor and the function of the dielectric allows the CAC-OS or CAC-metal oxide to have a switching function (function to control on / off). By separating each function in CAC-OS or CAC-metal oxide, each function can be maximized.

In this specification and the like, CAC-OS or CAC-metal oxide includes a conductor region and a dielectric region. The conductor region has the function of the conductor, and the dielectric region has the function of the dielectric. In addition, in the material, the conductor region and the dielectric region are sometimes separated at the nanoparticle level. In addition, the conductor region and the dielectric region may be unevenly distributed in the material. In addition, a region of the conductor whose edges are blurred and connected in a cloud shape is sometimes observed.

That is, CAC-OS or CAC-metal oxide may also be referred to as a matrix composite or a metal matrix composite.

In addition, in CAC-OS or CAC-metal oxide, the conductor region and the dielectric region are sometimes dispersed in the material in a size of 0.5 nm or more and 10 nm or less, preferably 0.5 nm or more and 3 nm or less.

    Embodiment 1    

In this embodiment, a display device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 23.

The display device of this embodiment includes a first display element that reflects visible light and a second display element that emits visible light.

The display device of this embodiment has a function of displaying an image by one or both of light reflected by a first display element and light emitted by a second display element.

As the first display element, an element that displays external light can be used. Since this element does not include a light source, the power consumption during display can be made extremely small.

As the first display element, a reflective liquid crystal element can be typically used. In addition, as the first display element, a shutter type MEMS (Micro Electro Mechanical System) element, a light interference type MEMS element, an applied microcapsule type, an electrophoresis type, an electrowetting type, and an electronic powder fluid ( Registered trademark in Japan) and other components.

As the second display element, a light-emitting element is preferably used. Since the brightness and chromaticity of the light emitted by such display elements are not affected by external light, such pixels can perform vivid displays with high color reproducibility (wide color gamut) and high contrast.

As the second display element, for example, a self-luminous light emitting element such as an OLED (Organic Light Emitting Diode), an LED (Light Emitting Diode), or a QLED (Quantum-dot Light Emitting Diode) can be used.

The display device of this embodiment includes a first mode for displaying an image using only a first display element, a second mode for displaying an image using only a second display element, and a third mode for displaying an image using a first display element and a second display element, The display device can be used by automatically or manually switching between these modes.

In the first mode, an image is displayed using a first display element and external light. Because the first mode does not use a light source, power consumption is extremely low. For example, when external light is sufficiently incident on the display device (under a bright environment or the like), display can be performed using light reflected by the first display element. For example, the first mode is effective when the external light is sufficiently strong and the external light is white or similar light. The first mode is a mode suitable for displaying text. In addition, since light reflecting external light is used in the first mode, an eye-protection display can be performed, and there is an effect that the eyes are not easily tired.

In the second mode, an image is displayed by the light emission of the second display element. This makes it possible to perform extremely vivid (high contrast and high color reproducibility) display regardless of illuminance and chromaticity of external light. For example, the second mode is effective when the illuminance at night or in a dark room is extremely low. In addition, when the surroundings are dim, the bright display sometimes makes the user feel dazzling. In order to prevent such a problem from occurring, it is preferable to perform a display with reduced brightness in the second mode. Thereby, not only glare can be suppressed, but also power consumption can be reduced. The second mode is a mode suitable for displaying sharp images (still images and moving images) and the like.

In the third mode, display is performed using both the reflected light from the first display element and the light emitted from the second display element. Not only can the display be sharper than the first mode, but the power consumption can be made smaller than that in the second mode. For example, the third mode is effective when the illuminance is low under indoor lighting or in the morning and evening, and when the chromaticity of external light is not white. In addition, by using a mixture of reflected light and luminous light, it is possible to display an image that looks like painting.

By adopting the above structure, a display device or an all-weather display device having high visibility and high convenience regardless of the surrounding brightness can be realized.

FIG. 1 shows a cross-sectional view of a display device 10. In the display device 10, a liquid crystal element 180 is included as a first display element, and a light emitting element 170 is included as a second display element.

The display device 10 shown in FIG. 1 includes a liquid crystal element 180, a light emitting element 170, a transistor 41, a transistor 42, and the like between a pair of substrates (a substrate 351 and a substrate 361).

The liquid crystal element 180 includes an electrode 311 having a function of reflecting visible light, a liquid crystal 112 and an electrode 113 having a function of transmitting visible light. The liquid crystal 112 is located between the electrode 311 and the electrode 113.

The liquid crystal element 180 has a function of reflecting visible light. The liquid crystal element 180 emits the reflected light 22 to the substrate 361 side.

The electrode 311 is electrically connected to a source or a drain included in the transistor 41 through an opening provided in the insulating layer 220. The electrode 311 is used as a pixel electrode. The electrode 113 is electrically connected to the conductive layer 235 through a connector 243. By processing the same conductive film, an electrode 311 and a conductive layer 235 can be obtained.

The light-emitting element 170 includes an electrode 191, an EL layer 192, and an electrode 193. The EL layer 192 is located between the electrode 191 and the electrode 193. The EL layer 192 contains at least a light-emitting substance. The electrode 191 has a function of transmitting visible light. The electrode 193 preferably has a function of reflecting visible light.

The light emitting element 170 has a function of emitting visible light. Specifically, the light-emitting element 170 is a field-effect light-emitting element that emits light (light-emitting 21) to the substrate 361 side by applying a voltage between the electrode 191 and the electrode 193.

The electrode 191 is electrically connected to a source or a drain included in the transistor 42 through an opening provided in the insulating layer 214. The electrode 191 functions as a pixel electrode. An end portion of the electrode 191 is covered with an insulating layer 216.

The light emitting element 170 is preferably covered with an insulating layer 194. In FIG. 1, the insulating layer 194 is provided so as to contact the electrode 193. By providing the insulating layer 194, the intrusion of impurities into the light-emitting element 170 can be suppressed and the reliability of the light-emitting element 170 can be improved. The adhesive layer 142 is used to adhere the insulating layer 194 and the substrate 351.

The transistor 41 and the transistor 42 are located on the same surface. The transistor 41 has a function of controlling the driving of the liquid crystal element 180. The transistor 42 has a function of controlling the driving of the light emitting element 170.

The circuit electrically connected to the liquid crystal element 180 is preferably formed on the same surface as the circuit electrically connected to the light emitting element 170. As a result, the thickness of the display device can be reduced compared to a case where two circuits are formed on different surfaces. In addition, since two transistors can be manufactured by the same process, the process can be simplified compared to a case where two transistors are formed on different faces.

The electrode 311 of the pixel electrode of the liquid crystal element 180 is located opposite to the electrode 191 of the pixel electrode of the light emitting element 170 via the gate insulating film included in the transistor 41 and the transistor 42.

Here, when the transistor 41 containing the oxide semiconductor with an extremely low off-state current in the channel formation region or a memory element electrically connected to the transistor 41 is used, the static state is displayed even when the liquid crystal element 180 is used. Stopping the writing to the pixel during the image can also maintain the gray level. That is, even if the frame frequency is made extremely small, the display can be maintained. In one embodiment of the present invention, the frame frequency can be made extremely small, and driving with low power consumption can be performed.

Next, a configuration example of the display device of the present embodiment will be described with reference to FIGS. 2 to 7D.

    <Structural Example 1>    

FIG. 2 is a schematic perspective view of a display device 300. The display device 300 has a structure in which the substrate 351 and the substrate 361 are bonded together. In FIG. 2, the substrate 361 is indicated by a dotted line.

The display device 300 includes a display section 362, a circuit 364, a wiring 365, and the like. FIG. 2 shows an example in which an IC (Integrated Circuit) 373 and an FPC 372 are mounted on the display device 300. Therefore, the structure shown in FIG. 2 may be referred to as a display module including the display device 300, IC, and FPC.

As the circuit 364, for example, a scanning line driving circuit can be used.

The wiring 365 has a function of supplying signals and power to the display portion 362 and the circuit 364. This signal and power are input to the wiring 365 from the outside via the FPC372 or from the IC373.

FIG. 2 shows an example in which the IC 373 is provided on the substrate 351 by a COG (Chip On Glass) method or a COF (Chip on Film) method. As the IC373, for example, an IC including a scanning line driving circuit or a signal line driving circuit can be used. Note that the display device 300 and the display module may not be provided with an IC. In addition, the IC may be mounted on an FPC using a COF method or the like.

FIG. 2 shows an enlarged view of a part of the display section 362. In the display section 362, electrodes 311b included in a plurality of display elements are arranged in a matrix. The electrode 311 b has a function of reflecting visible light, and is used as a reflective electrode of the liquid crystal element 180.

In addition, as shown in FIG. 2, the electrode 311 b has an opening 451. The display portion 362 includes a light-emitting element 170 on a side closer to the substrate 351 than the electrode 311b. The light from the light emitting element 170 is emitted to the substrate 361 side through the opening 451 of the electrode 311b.

FIG. 3 shows an example of a cross section of a part of the area including the FPC 372, a part of the area including the circuit 364, and a part of the area including the display portion 362 of the display device 300 shown in FIG.

The display device 300 shown in FIG. 3 includes a transistor 201, a transistor 203, a transistor 205, a transistor 206, a liquid crystal element 180, a light emitting element 170, an insulating layer 220, a color layer 131, and a color between a substrate 351 and a substrate 361. Layer 134 and so on. The substrate 361 and the insulating layer 220 are bonded by an adhesive layer 141. The substrate 351 and the insulating layer 220 are bonded by an adhesive layer 142.

On the substrate 361, a color layer 131, a light-shielding layer 132, an insulating layer 121, and an electrode 113 used as a common electrode of the liquid crystal element 180, an alignment film 133b, an insulating layer 117, and the like are provided. A polarizing plate 135 is provided on the outer surface of the substrate 361. The insulating layer 121 may have a function of a planarization layer. By providing the insulating layer 121, the surface of the electrode 113 can be made substantially flat, and the alignment state of the liquid crystal 112 can be made uniform. The insulating layer 117 is used as a spacer for maintaining a cell gap of the liquid crystal element 180.

The liquid crystal element 180 is a reflective liquid crystal element. The liquid crystal element 180 has a stacked structure in which an electrode 311a, a liquid crystal 112, and an electrode 113 are laminated. An electrode 311b that reflects visible light is provided so as to be in contact with the substrate 351 side of the electrode 311a. The electrode 311b has an opening 451. The electrodes 311a and the electrodes 113 transmit visible light. An alignment film 133a is provided between the liquid crystal 112 and the electrode 311a. An alignment film 133b is provided between the liquid crystal 112 and the electrode 113.

In the liquid crystal element 180, the electrode 311b has a function of reflecting visible light, and the electrode 113 has a function of transmitting visible light. The light incident from the substrate 361 side is polarized by the polarizing plate 135, passes through the electrode 113 and the liquid crystal 112, and is reflected by the electrode 311b. Then, it passes through the liquid crystal 112 and the electrode 113 again and reaches the polarizing plate 135. At this time, the alignment of the liquid crystal can be controlled by the voltage applied between the electrode 311b and the electrode 113 to control the optical modulation of light. That is, the intensity of light emitted through the polarizing plate 135 can be controlled. In addition, since light outside the specified wavelength region of the light is absorbed by the color layer 131, the extracted light becomes, for example, red light.

As shown in FIG. 3, the opening 451 is preferably provided with an electrode 311 a that transmits visible light. As a result, the liquid crystal 112 is aligned in the same region as the other regions in the region overlapping the opening 451, and it is possible to suppress unintended light leakage due to poor alignment of the liquid crystal at the boundary portion of the region.

In the connection portion 207, the electrode 311b is electrically connected to the conductive layer 222a included in the transistor 206 through the conductive layer 221b. The transistor 206 has a function of suppressing the driving of the liquid crystal element 180.

A connection portion 252 is provided in a region where a part of the adhesive layer 141 is provided. In the connection portion 252, the conductive layer 311 e obtained by processing the same conductive film as the electrode 311 a is electrically connected to a part of the electrode 113 by the connector 243. Accordingly, a signal or a potential input from the FPC 372 connected to the substrate 351 side can be supplied to the electrode 113 formed on the substrate 361 side through the connection portion 252.

In the connection portion 252, the conductive layer 311e and the conductive layer 311f are formed using the same material as the electrode 311a and the electrode 311b so as to cover the recessed portions formed in the resin layer 62a and the insulating layer 63.器 243 is in contact. By forming the conductive layer 311e and the conductive layer 311f so as to cover the recessed portions formed in the resin layer 62a and the insulating layer 63, the conductive layer 311e is easily exposed.

The connector 243 can use conductive particles, for example. As the conductive particles, particles such as organic resin or silicon dioxide whose surface is covered with a metal material can be used. As the metal material, nickel or gold is preferably used because it can reduce contact resistance. It is preferable to use particles in which two or more kinds of metal materials are covered in a layer form, such as covering gold with nickel. As the connector 243, a material capable of elastic deformation or plastic deformation is preferably used. At this time, the connector 243 of the conductive particles may be flattened in the longitudinal direction as shown in FIG. 3. By having this shape, the contact area between the connector 243 and the conductive layer electrically connected to the connector 243 can be increased, so that the contact resistance can be reduced and problems such as poor contact can be suppressed.

The connector 243 is preferably arranged so as to be covered with the adhesive layer 141. For example, the connectors 243 may be dispersed in the adhesive layer 141 before being cured.

The light emitting element 170 is a bottom emission type light emitting element. The light-emitting element 170 has a structure in which an electrode 191, an EL layer 192, and an electrode 193 are stacked in this order from the insulating layer 220 side. The electrode 191 is connected to the conductive layer 222 b included in the transistor 205 through an opening provided in the insulating layer 214. The transistor 205 has a function of controlling the driving of the light emitting element 170. The insulating layer 216 covers an end portion of the electrode 191. The electrode 193 includes a material that reflects visible light, and the electrode 191 includes a material that transmits visible light. The insulating layer 194 is provided so as to cover the electrode 193. The light emitted from the light emitting element 170 is emitted to the substrate 361 side through the color layer 134, the insulating layer 220, the opening 451, and the electrode 311a.

When the color of the color layer is changed according to the pixels, the liquid crystal element 180 and the light-emitting element 170 can exhibit various colors. The display device 300 can perform color display using the liquid crystal element 180. The display device 300 can perform color display using the light emitting element 170.

The transistor 201, the transistor 203, the transistor 205, and the transistor 206 are all formed on the side of the substrate 351 of the insulating layer 220. These transistors can be manufactured by the same process.

The transistor 203 is a transistor (also referred to as a switching transistor or a selection transistor) for controlling whether a pixel is selected. The transistor 205 is a transistor (also referred to as a driving transistor) for controlling a current flowing through the light emitting element 170.

An insulating layer such as an insulating layer 211, an insulating layer 212, an insulating layer 213, and an insulating layer 214 is provided on the substrate 351 side of the insulating layer 220. A part of the insulating layer 211 is used as a gate insulating layer of each transistor. The insulating layer 212 is provided so as to cover the transistor 206 and the like. The insulating layer 213 is provided so as to cover the transistor 205 and the like. The insulating layer 214 is used as a planarization layer. Note that there is no particular limitation on the number of insulating layers covering the transistor, and it may be either one or two or more.

Preferably, a material that does not easily diffuse impurities such as water or hydrogen is used for at least one of the insulating layers covering each transistor. Thereby, an insulating layer can be used as a barrier film. By adopting such a structure, it is possible to effectively suppress impurities from diffusing into the transistor from the outside, so that a highly reliable display device can be realized.

The transistor 201, the transistor 203, the transistor 205, and the transistor 206 include a conductive layer 221a used as a gate electrode, an insulating layer 211 used as a gate insulating layer, and a conductive layer used as a source and a drain, respectively. 222a, the conductive layer 222b, and the semiconductor layer 231. Here, the same hatching pattern is attached to a plurality of layers obtained by processing the same conductive film.

The transistor 201 and the transistor 205 include a conductive layer 223 used as a gate in addition to the structures of the transistor 203 and the transistor 206.

As the transistor 201 and the transistor 205, a structure in which a semiconductor layer forming a channel is sandwiched by two gates is adopted. By adopting this structure, the threshold voltage of the transistor can be controlled. In addition, it is also possible to connect two gates and drive the transistor by supplying the same signal to the two gates. Compared with other transistors, this transistor can increase the field-effect mobility and increase the on-state current. As a result, a circuit capable of high-speed driving can be manufactured. Furthermore, the area occupied by the circuit portion can be reduced. By using a transistor having a large on-state current, even if the number of wirings increases due to the increase in the size or resolution of the display device, the signal delay of each wiring can be reduced, and display unevenness can be suppressed.

Alternatively, the threshold voltage of the transistor can be controlled by applying a potential for controlling the critical voltage to one of the two gates and applying a potential for driving the other.

There is no limitation on the structure of the transistor included in the display device. The transistor included in the circuit 364 and the transistor included in the display portion 362 may have the same structure or different structures. The plurality of transistors included in the circuit 364 may both have the same structure, or may combine two or more structures. Similarly, the plurality of transistors included in the display section 362 may all have the same structure, or two or more structures may be combined.

The conductive layer 223 is preferably formed using a conductive material containing an oxide. By forming the conductive film constituting the conductive layer 223 in an atmosphere containing oxygen, oxygen can be supplied to the insulating layer 212. Preferably, the ratio of the oxygen gas in the deposition gas is 90% or more and 100% or less. Oxygen supplied to the insulating layer 212 is supplied to the semiconductor layer 231 by a subsequent heat treatment, whereby reduction of oxygen defects in the semiconductor layer 231 can be achieved.

In particular, as the conductive layer 223, an oxide semiconductor having a reduced resistance is preferably used. In this case, it is preferable to use an insulating film that releases hydrogen to the insulating layer 213, such as a silicon nitride film. Hydrogen is supplied to the conductive layer 223 by the heat treatment in the film formation of the insulating layer 213 or later, whereby the resistance of the conductive layer 223 can be effectively reduced.

A color layer 134 is provided so as to be in contact with the insulating layer 213. The color layer 134 is covered with an insulating layer 214.

A connection portion 204 is provided in a region of the substrate 351 that does not overlap the substrate 361. In the connection portion 204, the wiring 365 is electrically connected to the FPC 372 through the connection layer 242. In the connection portion 204, the conductive layer 311c and the conductive layer 311d are formed using the same material as the electrode 311a and the electrode 311b so as to cover the recessed portions formed in the resin layer 62a and the insulating layer 63, and are exposed on the top surface of the connection portion 204 There is a conductive layer 311c. Therefore, the connection portion 204 can be electrically connected to the FPC 372 through the connection layer 242. By forming the conductive layer 311c and the conductive layer 311d so as to cover the recessed portions formed in the resin layer 62a and the insulating layer 63, the conductive layer 311c is easily exposed on the top surface of the connection portion 204.

As the polarizing plate 135 provided on the outer surface of the substrate 361, a linear polarizing plate or a circular polarizing plate may be used. As the circular polarizing plate, for example, a polarizing plate in which a linear polarizing plate and a quarter wave retardation plate are laminated can be used. This can suppress external light reflection. In addition, by adjusting the cell gap, alignment, driving voltage, and the like of the liquid crystal element used for the liquid crystal element 180 according to the type of the polarizing plate, a desired contrast can be achieved.

In addition, various optical members may be arranged on the outer surface of the substrate 361. As the optical member, a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, a condensing film, and the like can be used. In addition, an antistatic film that suppresses adhesion of dust, a water-repellent film that is not easily stained, a hard coating film that suppresses damage during use, and the like may be disposed on the outer surface of the substrate 361.

The substrate 351 and the substrate 361 can be made of glass, quartz, ceramics, sapphire, or organic resin. By using a flexible material for the substrate 351 and the substrate 361, the flexibility of the display device can be improved.

As the liquid crystal element 180, for example, an element using a VA (Vertical Alignment) mode can be used. As the vertical alignment mode, MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode, ASV (Advanced Super View) mode, etc. can be used.

As the liquid crystal element 180, a liquid crystal element using various modes can be used. For example, in addition to VA (Vertical Alignment) mode, TN (Twisted Nematic: twisted nematic) mode, IPS (In-Plane-Switching: plane switching) mode, FFS (Fringe Field Switching) Mode, ASMally (Axially Symmetric aligned Micro-cell) mode, OCB (Optically Compensated Birefringence) mode, FLC (Ferroelectric Liquid Crystal) mode, AFLC (AntiFerroelectric Liquid Crystal: Anti-ferroelectric liquid crystal) mode.

A liquid crystal element is an element that controls the transmission or non-transmission of light by using the optical modulation effect of liquid crystal. The optical modulation effect of a liquid crystal is controlled by an electric field (including a lateral electric field, a longitudinal electric field, or an oblique electric field) applied to the liquid crystal. As the liquid crystal used for the liquid crystal element, thermotropic liquid crystal, low-molecular liquid crystal, polymer liquid crystal, polymer dispersed liquid crystal (PDLC: Polymer Dispersed Liquid Crystal), ferroelectric liquid crystal, and antiferroelectric liquid crystal can be used. These liquid crystal materials exhibit a cholesteric phase, a smectic phase, a cubic phase, a hand nematic phase, and isotropic isotropy according to conditions.

As the liquid crystal material, a positive type liquid crystal or a negative type liquid crystal can be used, and an appropriate liquid crystal material can be used depending on the applicable mode or design.

In order to control the alignment of the liquid crystal, an alignment film may be provided. In addition, when a lateral electric field method is used, a blue-phase liquid crystal that does not use an alignment film may be used. The blue phase is a type of liquid crystal phase, and refers to a phase that is about to transition from the cholesterol phase to the isotropic phase when the temperature of the cholesteric liquid crystal is raised. Since the blue phase appears only in a narrow temperature range, a liquid crystal composition in which a chiral agent of several wt% or more is mixed is used for the liquid crystal layer to expand the temperature range. A liquid crystal composition containing a blue phase-containing liquid crystal and a chiral agent has a fast response speed and is optically isotropic. In addition, a liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent does not require alignment treatment, and has a small viewing angle dependency. In addition, since it is not necessary to provide an alignment film without rubbing treatment, electrostatic damage caused by rubbing treatment can be prevented, and defects and breakage of the liquid crystal display device in the manufacturing process can be reduced.

When a reflective liquid crystal element is used, the polarizing plate 135 is provided on the display surface side. In addition, when a light diffusing plate is additionally provided on the display surface side, it is possible to improve visibility, so it is preferable.

A front light source may be provided outside the polarizing plate 135. As the front light source, an edge-illumination type front light source is preferably used. When using a front light source with LED (Light Emitting Diode), power consumption can be reduced, so it is better.

As the adhesive layer, various hardening adhesives such as a light hardening adhesive such as an ultraviolet hardening adhesive, a reaction hardening adhesive, a thermosetting adhesive, and an anaerobic adhesive can be used. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenol resins, polyimide resins, polyimide resins, PVC (polyvinyl chloride) resins, and PVB (polyvinyl butyral). Resin, EVA (ethylene-vinyl acetate) resin, etc. In particular, it is preferable to use a material having low moisture permeability such as epoxy resin. Alternatively, a two-liquid mixed resin may be used. Alternatively, an adhesive sheet or the like may be used.

As the connection layer 242, an anisotropic conductive film (ACF: Anisotropic Conductive Film), an anisotropic conductive paste (ACP: Anisotropic Conductive Paste), or the like can be used.

The light emitting element 170 has a top emission structure, a bottom emission structure, or a double-sided emission structure. As the electrode on the light extraction side, a conductive film that transmits visible light is used. In addition, it is preferable to use a conductive film that reflects visible light as the electrode that does not extract light.

The EL layer 192 includes at least a light emitting layer. As a layer other than the light emitting layer, the EL layer 192 may further include a substance having a high hole injection property, a substance having a high hole transport property, a hole blocking material, a substance having a high electron transport property, a substance having a high electron injection property, or A layer of a polar substance (a substance having a high electron-transporting property and a hole-transporting property).

As the EL layer 192, a low-molecular compound or a high-molecular compound may be used, and an inorganic compound may be further included. The layers constituting the EL layer 192 are each formed by a method such as a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, and a coating method.

The EL layer 192 may include an inorganic compound such as a quantum dot. For example, by using a quantum dot for a light emitting layer, it can also be used as a light emitting material. As the quantum dot material, a colloidal quantum dot material, an alloy type quantum dot material, a core shell type quantum dot material, a core type quantum dot material, or the like can be used. In addition, materials containing element groups of the 12th and 16th groups, the 13th and 15th groups, the 14th and the 16th group may be used. Alternatively, a quantum dot material containing elements such as cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium, lead, gallium, arsenic, aluminum, and the like can be used.

In addition, by using a combination of a color filter (color layer) and a microcavity structure (optical adjustment layer), light with excellent purity can be extracted from a display device. The thickness of the optical adjustment layer changes according to the color of each pixel.

Examples of materials that can be used for conductive layers such as gates, sources and drains of transistors, and various wirings and electrodes constituting display devices include aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, Metals such as tantalum or tungsten, or alloys containing the above metals as main components. Films containing these materials can be used in a single-layer or stacked structure.

In addition, as the light-transmitting conductive material, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide to which gallium is added, or graphene can be used. Alternatively, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or an alloy material containing the metal material can be used. Alternatively, a nitride of the metal material (e.g., titanium nitride) or the like can also be used. In addition, when a metal material or an alloy material (or a nitride thereof) is used, it may be formed to be thin so as to have translucency. In addition, a laminated film of the above materials can be used as the conductive layer. For example, the use of a multilayer film of an alloy of silver and magnesium with indium tin oxide can improve conductivity, and is therefore preferred. The above-mentioned materials can also be used for conductive layers constituting various wirings and electrodes of a display device, and conductive layers (conductive layers used as pixel electrodes and common electrodes) included in display elements.

Examples of the insulating material usable for each insulating layer include resins such as acrylic resins and epoxy resins, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, or aluminum oxide.

Examples of the material that can be used for the color layer include a metal material, a resin material, and a resin material containing a pigment or a dye.

    <Structural Example 2>    

The main difference between the display device 300A and the display device 300 shown in FIG. 4 is that the display device 300A does not include the transistor 201, the transistor 203, the transistor 205, and the transistor 206 but includes the transistor 281 and the transistor 284, transistor 285, and transistor 286.

As shown in the transistor 284 and the transistor 285, two transistors included in the display device may be partially laminated. As a result, the area occupied by the pixel circuit can be reduced, and the resolution can be improved. In addition, since the light emitting area of the light emitting element 170 can be increased, the aperture ratio can be increased. When the aperture ratio of the light-emitting element 170 is high, the current density when the required brightness is obtained can be reduced, and the reliability can be improved.

The transistor 281, the transistor 284, and the transistor 286 include a conductive layer 221a, an insulating layer 211, a semiconductor layer 231, a conductive layer 222a, and a conductive layer 222b. The conductive layer 221a overlaps the semiconductor layer 231 via the insulating layer 211. The conductive layers 222a and 222b are electrically connected to the semiconductor layer 231. The transistor 281 includes a conductive layer 223.

The transistor 285 includes a conductive layer 222b, an insulating layer 217, a semiconductor layer 261, a conductive layer 223, an insulating layer 212, an insulating layer 213, a conductive layer 263a, and a conductive layer 263b. The conductive layer 222b overlaps the semiconductor layer 261 via the insulating layer 217. The conductive layer 223 overlaps the semiconductor layer 261 via the insulating layer 212 and the insulating layer 213. The conductive layers 263a and 263b are electrically connected to the semiconductor layer 261.

The conductive layer 221a is used as a gate electrode. The insulating layer 211 is used as a gate insulating layer. The conductive layer 222a is used as one of a source and a drain. The conductive layer 222b included in the transistor 286 is used as the other of the source and the drain.

The conductive layer 222 b used in common with the transistor 284 and the transistor 285 has a portion used as the other of the source and the drain of the transistor 284 and a portion used as the gate of the transistor 285. The insulating layer 217, the insulating layer 212, and the insulating layer 213 are used as a gate insulating layer. One of the conductive layers 263a and 263b is used as a source, and the other is used as a drain. The conductive layer 223 is used as a gate.

    <Structural Example 3>    

FIG. 5A is a cross-sectional view of a display portion of the display device 300B.

The display device 300B is different from the display device 300 in that the display device 300B does not include the color layer 131. The other structures are the same as those of the display device 300, so detailed descriptions are omitted.

The liquid crystal element 180 appears white. Since the display device 300 does not include the color layer 131, the liquid crystal element 180 can be used for display in black and white or gray scale.

    <Structural Example 4>    

The display device 300C shown in FIG. 5B is different from the display device 300B in that the display device 300C is respectively coated with the EL layer 192 and does not include the color layer 134. The other structures are the same as those of the display device 300B, so detailed descriptions are omitted.

In the light-emitting element 170 using the separate coating method, at least one of the layers constituting the EL layer 192 (typically a light-emitting layer) may be separately coated, or all the layers constituting the EL layer may be separately coated.

In one embodiment of the present invention, the structure of the transistor included in the display device is not particularly limited. For example, a planar transistor, an interleaved transistor, or an anti-interleaved transistor can be used. In addition, the transistors may each have a top-gate structure or a bottom-gate structure. Alternatively, gate electrodes may be provided above and below the channel.

6A to 6E illustrate a structural example of a transistor.

The transistor 110a shown in FIG. 6A is a transistor having a top-gate structure.

The transistor 110a includes a conductive layer 221, an insulating layer 211, a semiconductor layer 231, an insulating layer 212, a conductive layer 222a, and a conductive layer 222b. The semiconductor layer 231 is provided on the insulating layer 151. The conductive layer 221 overlaps with the semiconductor layer 231 via the insulating layer 211. The conductive layer 222a and the conductive layer 222b are electrically connected to the semiconductor layer 231 through openings formed in the insulating layer 211 and the insulating layer 212.

The conductive layer 221 is used as a gate. The insulating layer 211 is used as a gate insulating layer. One of the conductive layers 222a and 222b is used as a source, and the other is used as a drain.

Since the physical distance between the conductive layer 221 and the conductive layer 222a or the conductive layer 221 and the conductive layer 222b is easily separated in the transistor 110a, the parasitic capacitance between them can be reduced.

The transistor 110b shown in FIG. 6B includes a conductive layer 223 and an insulating layer 218 in addition to the structure of the transistor 110a. The conductive layer 223 is disposed on the insulating layer 151 and overlaps the semiconductor layer 231. The insulating layer 218 is provided so as to cover the conductive layer 223 and the insulating layer 151.

The conductive layer 223 is used as one of a pair of gate electrodes. This makes it possible to increase the on-state current of the transistor and control the threshold voltage.

6C to 6E show examples of a structure in which two transistors are stacked. The structure of the two stacked transistors can be determined independently, and is not limited to the combination of FIGS. 6C to 6E.

FIG. 6C shows a structure of a stacked transistor 110c and a transistor 110d. The transistor 110c includes two gate electrodes. The transistor 110d has a bottom gate structure. In addition, the number of the gates of the transistor 110c may be one (top gate structure). In addition, the number of the gates of the transistor 110d may be two.

The transistor 110c includes a conductive layer 223, an insulating layer 218, a semiconductor layer 231, a conductive layer 221, an insulating layer 211, a conductive layer 222a, and a conductive layer 222b. The conductive layer 223 is disposed on the insulating layer 151. The conductive layer 223 overlaps with the semiconductor layer 231 via the insulating layer 218. The insulating layer 218 is provided so as to cover the conductive layer 223 and the insulating layer 151. The conductive layer 221 overlaps with the semiconductor layer 231 via the insulating layer 211. Although FIG. 6C shows an example in which the insulating layer 211 is provided only in a portion overlapping the conductive layer 221, as shown in FIG. 6B and the like, the insulating layer 211 may be provided so as to cover the end portion of the semiconductor layer 231. The conductive layer 222a and the conductive layer 222b are electrically connected to the semiconductor layer 231 through an opening formed in the insulating layer 212.

The transistor 110d includes a conductive layer 222b, an insulating layer 213, a semiconductor layer 261, a conductive layer 263a, and a conductive layer 263b. The conductive layer 222b has a region overlapping the semiconductor layer 261 via the insulating layer 213. The insulating layer 213 is provided so as to cover the conductive layer 222b. The conductive layers 263a and 263b are electrically connected to the semiconductor layer 261.

Both the conductive layer 221 and the conductive layer 223 are used as gates of the transistor 110c. Both the insulating layer 218 and the insulating layer 211 are used as a gate insulating layer of the transistor 110c. The conductive layer 222a is used as one of a source and a drain of the transistor 110c.

The conductive layer 222b includes a portion used as the other of the source and the drain of the transistor 110c and a portion used as the gate of the transistor 110d. The insulating layer 213 is used as a gate insulating layer of the transistor 110d. One of the conductive layer 263a and the conductive layer 263b is used as the source of the transistor 110d, and the other of the conductive layer 263a and the conductive layer 263b is used as the drain of the transistor 110d.

The transistor 110c and the transistor 110d are preferably used for the pixel circuit of the light emitting element 170. For example, the transistor 110c may be used as a selection transistor, and the transistor 110d may be used as a driving transistor.

The conductive layer 263b is electrically connected to an electrode 191 of a pixel electrode used as a light emitting element through an opening formed in the insulating layer 217 and the insulating layer 214.

FIG. 6D shows a structure of a stacked transistor 110e and a transistor 110f. The transistor 110e has a bottom gate structure. The transistor 110f includes two gate electrodes. In addition, the number of the gates of the transistor 110e may be two.

The transistor 110e includes a conductive layer 221, an insulating layer 211, a semiconductor layer 231, a conductive layer 222a, and a conductive layer 222b. The conductive layer 221 is disposed on the insulating layer 151. The conductive layer 221 overlaps with the semiconductor layer 231 via the insulating layer 211. The insulating layer 211 is provided so as to cover the conductive layer 221 and the insulating layer 151. The conductive layers 222a and 222b are electrically connected to the semiconductor layer 231.

The transistor 110f includes a conductive layer 222b, an insulating layer 212, a semiconductor layer 261, a conductive layer 223, an insulating layer 218, an insulating layer 213, a conductive layer 263a and a conductive layer 263b. The conductive layer 222b has a region overlapping the semiconductor layer 261 via the insulating layer 212. The insulating layer 212 is provided so as to cover the conductive layer 222b. The conductive layer 263a and the conductive layer 263b are electrically connected to the semiconductor layer 261 through an opening formed in the insulating layer 213. The conductive layer 223 overlaps the semiconductor layer 261 via the insulating layer 218. The insulating layer 218 is provided at a portion overlapping the conductive layer 223.

The conductive layer 221 is used as a gate of the transistor 110e. The insulating layer 211 is used as a gate insulating layer of the transistor 110e. The conductive layer 222a is used as one of a source and a drain of the transistor 110e.

The conductive layer 222b includes a portion used as the other of the source and the drain of the transistor 110e and a portion used as the gate of the transistor 110f. The conductive layer 223 is used as a gate of the transistor 110f. Both the insulating layer 212 and the insulating layer 218 are used as a gate insulating layer of the transistor 110f. One of the conductive layer 263a and the conductive layer 263b is used as the source of the transistor 110f, and the other of the conductive layer 263a and the conductive layer 263b is used as the drain of the transistor 110f.

The conductive layer 263b is electrically connected to an electrode 191 of a pixel electrode used as a light emitting element through an opening formed in the insulating layer 214.

FIG. 6E shows a structure of a stacked transistor 110g and a transistor 110h. The transistor 110g has a top gate structure. The transistor 110h includes two gate electrodes. In addition, the number of the gates of the transistor 110g may be two.

The transistor 110g includes a semiconductor layer 231, a conductive layer 221, an insulating layer 211, a conductive layer 222a, and a conductive layer 222b. The semiconductor layer 231 is provided on the insulating layer 151. The conductive layer 221 overlaps with the semiconductor layer 231 via the insulating layer 211. The insulating layer 211 overlaps the conductive layer 221. The conductive layer 222a and the conductive layer 222b are electrically connected to the semiconductor layer 231 through an opening formed in the insulating layer 212.

The transistor 110h includes a conductive layer 222b, an insulating layer 213, a semiconductor layer 261, a conductive layer 223, an insulating layer 218, an insulating layer 217, a conductive layer 263a, and a conductive layer 263b. The conductive layer 222b has a region overlapping the semiconductor layer 261 via the insulating layer 213. The insulating layer 213 is provided so as to cover the conductive layer 222b. The conductive layer 263a and the conductive layer 263b are electrically connected to the semiconductor layer 261 through an opening formed in the insulating layer 217. The conductive layer 223 overlaps the semiconductor layer 261 via the insulating layer 218. The insulating layer 218 is provided at a portion overlapping the conductive layer 223.

The conductive layer 221 is used as a gate of the transistor 110g. The insulating layer 211 is used as a gate insulating layer of the transistor 110g. The conductive layer 222a is used as one of a source and a drain of the transistor 110g.

The conductive layer 222b includes a portion used as the other of the source and the drain of the transistor 110g and a portion used as the gate of the transistor 110h. The conductive layer 223 is used as a gate of the transistor 110h. Both the insulating layer 213 and the insulating layer 218 are used as a gate insulating layer of the transistor 110h. One of the conductive layer 263a and the conductive layer 263b is used as the source of the transistor 110h, and the other of the conductive layer 263a and the conductive layer 263b is used as the drain of the transistor 110h.

The conductive layer 263b is electrically connected to an electrode 191 of a pixel electrode used as a light emitting element through an opening formed in the insulating layer 214.

Hereinafter, a method for manufacturing a display device according to this embodiment will be clearly described with reference to FIGS. 7A to 23.

The thin film (insulating film, semiconductor film, conductive film, etc.) constituting the display device can be formed by a sputtering method, a chemical vapor deposition (CVD: Chemical Vapor Deposition) method, a vacuum evaporation method, or a pulse laser deposition (PLD: Pulse Laser Deposition) ) Method, atomic layer deposition (ALD) method, and the like. As the CVD method, a plasma enhanced chemical vapor deposition (PECVD: Plasma Enhanced Chemical Vapor Deposition) method or a thermal CVD method may be used. As an example of the thermal CVD method, an organic metal chemical vapor deposition (MOCVD: Metal Organic CVD) method can be used.

The thin film (insulating film, semiconductor film, conductive film, etc.) constituting the display device can be formed by a spin coating method, a dipping method, a spraying method, an inkjet method, a dispenser method, a screen printing method, a lithographic printing method, or a doctor knife. It is formed by a method such as a slit coating method, a roll coating method, a curtain coating method, and a doctor blade coating method.

When the thin film constituting the display device is processed, it can be processed by a photolithography method or the like. In addition, an island-shaped thin film can be formed by a film forming method using a shadow mask. In addition, the film can be processed by a nano-imprint method, a sand blast method, a peeling method, or the like. In the photolithography method, there are the following methods: forming a photoresist mask on a film to be processed, processing the film by etching, and removing the photoresist mask; after forming a photosensitive film A method of performing exposure and development to process the film into a desired shape.

When light is used in the photolithography method, as the light used for exposure, for example, i-line (wavelength: 365 nm), g-line (wavelength: 436 nm), h-line (wavelength: 405 nm), or a mixture of these lights can be used. Into the light. In addition, ultraviolet light, KrF laser or ArF laser can also be used. In addition, exposure can also be performed using a liquid immersion exposure technique. As the light used for the exposure, extreme ultraviolet (EUV) or X-rays can also be used. Alternatively, an electron beam may be used instead of the light for exposure. When extreme ultraviolet light, X-rays, or electron beams are used, extremely fine processing can be performed, so it is preferable. In addition, when exposure is performed by scanning of a light beam such as an electron beam, a photomask is not required.

As a method of etching the thin film, a dry etching method, a wet etching method, a sandblasting method, or the like can be used.

    <Example of Manufacturing Method of Display Device>    

Hereinafter, an example of a method of manufacturing the display device 300 shown in FIG. 3 will be described. In FIGS. 7A to 23, a manufacturing method will be described with particular attention to the display portion 362 and the external connection portion of the display device 300.

First, a color layer 131 is formed on a substrate 361 (FIG. 7A). By forming the color layer 131 using a photolithography method or the like and using a photosensitive material, the color layer 131 can be processed into an island shape. In the circuit 364 and the like shown in FIG. 3, a light shielding layer 132 is provided on the substrate 361.

Next, an insulating layer 121 is formed on the color layer 131.

The insulating layer 121 is preferably used as a planarization layer. The insulating layer 121 can be formed using an acrylic resin, an epoxy resin, a polyamide resin, a polyimide resin, a siloxane resin, a benzocyclobutene-based resin, a phenol resin, or the like.

As the insulating layer 121, an inorganic insulating film can be used. When an inorganic insulating film is used as the insulating layer 121, for example, a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, an aluminum nitride film, or the like can be used. In addition, a hafnium oxide film, a yttrium oxide film, a zirconia film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film can also be used. In addition, two or more of the insulating films may be laminated.

Next, an electrode 113 is formed. The electrode 113 can be formed by forming a photoresist mask after forming a conductive film, etching the conductive film, and then removing the photoresist mask. The electrode 113 is formed using a conductive material that transmits visible light.

Next, an insulating layer 117 is formed on the electrode 113. As the insulating layer 117, an organic insulating film is preferably used.

Next, an alignment film 133b is formed on the electrode 113 and the insulating layer 117 (FIG. 7A). The alignment film 133b can be formed by performing a rubbing treatment after forming a thin film such as a resin.

In addition, the processes shown in FIGS. 7B to 10B are performed independently of the processes described with reference to FIG. 7A.

First, a resin layer 62 having a recessed portion is formed on the manufacturing substrate 61, and an insulating layer 63 is formed on the resin layer 62 (FIGS. 7B and 7C).

In this process, the following materials are selected: When the manufacturing substrate 61 is peeled off, a separated material is generated in the interface between the manufacturing substrate 61 and the resin layer 62, the interface between the resin layer 62 and the insulating layer 63, or the resin layer 62. Although the case where separation occurs at the interface between the insulating layer 63 and the resin layer 62 is exemplified in this embodiment, the position where the separation occurs depending on the combination of materials used for the resin layer 62 or the insulating layer 63 is not limited to this.

The manufacturing substrate 61 has rigidity to the extent that it can be easily conveyed, and has heat resistance to the temperature during the manufacturing process. Examples of the material that can be used for manufacturing the substrate 61 include glass, quartz, ceramics, sapphire, resin, semiconductor, metal, or alloy. Examples of the glass include alkali-free glass, barium borosilicate glass, and aluminoborosilicate glass.

The resin layer 62 is formed using a thermosetting material. In addition, the material may be photosensitive.

As a material that can be used for the resin layer 62, a polyimide resin is preferably used. In addition, examples of materials that can be used for the resin layer 62 include acrylic resins, epoxy resins, polyamide resins, polyimide resins, siloxane resins, and benzocyclobutenes. Resin, phenolic resin, etc. In addition, they are preferably photosensitive.

The resin layer 62 is formed by forming a film so as to have a thickness of 0.1 μm or more and 3 μm or less and subjecting the film to a heat treatment. The heat treatment can reduce the outgassing components (for example, hydrogen, water, etc.) in the resin layer 62. This heat treatment is preferably performed at a temperature higher than the manufacturing temperature of each layer formed on the resin layer 62. For example, when the maximum manufacturing temperature of the transistor is 350 ° C., it is preferable to heat the film to be the resin layer 62 at a temperature higher than 350 ° C. As a result, degassing from the resin layer 62 can be significantly suppressed during the manufacturing process of the transistor.

Specifically, heating is preferably performed at a temperature of 350 ° C. or higher and 450 ° C. or lower, and the upper limit heating temperature is preferably 400 ° C. or lower, more preferably lower than 400 ° C., and even more preferably lower than 375 ° C.

In one embodiment of the present invention, it is preferable to use a material having photosensitivity. Therefore, a part of the material having photosensitivity can be removed by a photolithography method using light. Specifically, after a film is formed using this material, the film is subjected to a heat treatment (also referred to as a pre-bake treatment) to remove the solvent, and then exposed using a photomask. Then, by performing a development process, unnecessary portions can be removed. In addition, it is preferable to perform a heat treatment (also referred to as a post-bake treatment) afterwards. In the post-baking process, as described above, the heating is preferably performed at a temperature higher than the manufacturing temperature of each layer formed on the resin layer 62.

The resin layer 62 has flexibility. By using a substrate having a lower flexibility than the resin layer 62 as the manufacturing substrate 61, the resin layer 62 can be easily transferred.

Examples of the method for forming the resin layer 62 include a spin coating method, a dipping method, a spray coating method, an inkjet method, a dispenser method, a screen printing method, a lithographic method, a doctor blade method, a slit coating method, and a roll coating method. , Curtain coating method, doctor blade coating method, etc.

The resin layer 62 is preferably formed using a spin coater. By using the spin coating method, a thin film can be uniformly formed on a large substrate.

The resin layer 62 is preferably formed using a solution having a viscosity of 5 cP or more and less than 500 cP, preferably 5 cP or more and less than 100 cP, and more preferably 10 cP or more and 50 cP or less. The lower the viscosity of the solution, the easier it is to apply. In addition, the lower the viscosity of the solution, the more the bubbles can be prevented from being mixed in, and a high-quality film can be formed.

The thickness of the resin layer 62 is preferably 0.01 μm or more and less than 10 μm, more preferably 0.1 μm or more and 3 μm or less, and still more preferably 0.5 μm or more and 1 μm or less. By using a low viscosity solution, the resin layer 23 can be easily formed thin.

The thermal expansion coefficient of the resin layer 62 is preferably from 0.1 ppm / ° C to 20 ppm / ° C, and more preferably from 0.1 ppm / ° C to 10 ppm / ° C. The lower the thermal expansion coefficient of the resin layer 62 is, the more the breakage of the transistor and the like caused by heating can be suppressed.

In addition, in one embodiment of the present invention, a portion of the resin layer 62 corresponding to the portion of the external connection portion in the thickness direction is removed, and thus the resin layer 62 is formed to have a first region and its thickness is thinner than the first region. The second region (also referred to as a recessed portion) of the resin layer 62.

When a photosensitive material is used as the material of the resin layer 62, after forming a film using the material, a heat treatment (also referred to as a pre-baking treatment) for removing a solvent is performed under the above conditions, and then a photomask is used. Make an exposure. Then, by performing a development process, unnecessary portions can be removed. Next, the film processed into a desired shape is heated (also referred to as a post-baking process) to form a resin layer 62 (FIG. 7B). When the exposure is performed, the resin layer 62 having the recessed portion can be formed by reducing the exposure amount compared to the conditions for forming the opening in the resin layer 62. For example, there can be mentioned a method of shortening the exposure time, reducing the intensity of light, and shifting the focus of light compared to the exposure conditions for forming an opening in the resin layer 62. Alternatively, multiple grayscale masks can be used.

In addition, it is also possible to form the recessed portion by embossing after forming a film using the material of the resin layer 62, before the pre-baking process, or after the pre-baking process and before the post-baking process, in which the The mold is pressed against the formed film.

When the side surface of the recessed portion of the resin layer 62 has a tapered shape, the coverage of the film formed on the recessed portion of the resin layer 62 is improved. Therefore, a positive resin is preferably used when a photosensitive resin is used, and a mold having a tapered shape is preferably used when imprinting is performed.

A second region having a thinner thickness than the first region is formed in the resin layer 62, and a conductive layer is provided so as to cover the second region, so that the conductive layer can be easily exposed in a later process. In addition, even if the resin layer is removed until the conductive layer is exposed, a part of the resin layer remains, so the remaining resin layer can be used as a protective layer.

The insulating layer 63 is formed at a temperature lower than the heat-resistant temperature of the resin layer 62 (FIG. 7C). Further, it is preferably formed at a temperature lower than the heating temperature in the heating process of the resin layer 62.

The insulating layer 63 can be used as a barrier layer that prevents impurities contained in the resin layer 62 from diffusing to a transistor or a display element formed later. For example, when the insulating layer 63 heats the resin layer 62, it is preferable to prevent moisture or the like contained in the resin layer 62 from diffusing into the transistor or the display element. Therefore, the insulating layer 63 preferably has high barrier properties.

As the insulating layer 63, for example, an inorganic insulating film such as a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or an aluminum nitride film can be used. In addition, a hafnium oxide film, a yttrium oxide film, a zirconia film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, a neodymium oxide film, and the like. In addition, two or more of the insulating films may be laminated. In particular, it is preferable to form a silicon nitride film on the resin layer 23 and to form a silicon oxide film on the silicon nitride film. Since the inorganic insulating film becomes a dense and highly barrier film as the film forming temperature becomes higher, it is preferably formed at a high temperature.

When an inorganic insulating film is used as the insulating layer 63, the temperature when the insulating layer 63 is formed is preferably room temperature (25 ° C) or higher and 350 ° C or lower, and more preferably 100 ° C or higher and 300 ° C or lower.

When the surface of the resin layer 62 has an uneven shape, the insulating layer 63 preferably covers the uneven shape. The insulating layer 63 may have a function of a planarizing layer that flattens the uneven shape. For example, as the insulating layer 63, a stack of an organic insulating material and an inorganic insulating material is preferably used. Examples of the organic insulating material include resins that can be used for the resin layer 62.

When an organic insulating film is used as the insulating layer 63, the temperature when forming the insulating layer 63 is preferably room temperature or higher and 350 ° C or lower, and more preferably room temperature or higher and 300 ° C or lower.

In addition, by forming the insulating layer 63, it is possible to suppress the expansion or contraction of the resin layer 62 caused by the subsequent display device process, and it is possible to improve the yield.

Next, an electrode 311a and a conductive layer 311c are formed on the insulating layer 63, an electrode 311b is formed on the electrode 311a, and a conductive layer 311d is formed on the conductive layer 311c (FIG. 7D). The electrode 311b has an opening 451 in the electrode 311a. The electrodes 311a, 311b, the conductive layer 311c, and the conductive layer 311d can be formed after forming a conductive film, etching the conductive film, and then removing the photoresist mask. The electrode 311a is formed using a conductive material that transmits visible light. The electrode 311b is formed using a conductive material that reflects visible light. The conductive layer 311c is formed using the same material as the electrode 311a, and the conductive layer 311d is formed using the same material as the electrode 311b.

Next, an insulating layer 220 is formed (FIG. 8A). In addition, openings are formed in the insulating layer 220 to reach the electrodes 311b and the conductive layer 311d, respectively.

The insulating layer 220 can be used as a barrier layer that prevents impurities contained in the resin layer 62 from diffusing into a transistor or a display element to be formed later. When an organic material is used as the resin layer 62, it is preferable that the insulating layer 220 prevents moisture and the like contained in the resin layer 62 from being diffused to the transistor or the display element when the resin layer 62 is heated. Therefore, the insulating layer 220 preferably has high barrier properties.

The insulating layer 220 can be formed using an inorganic insulating film, a resin, or the like that can be used for the insulating layer 121.

Next, a transistor 203, a transistor 205, and a transistor 206 are formed on the insulating layer 220.

The semiconductor material used for the transistor is not particularly limited, and for example, a Group 14 element, a compound semiconductor, or an oxide semiconductor can be used for the semiconductor layer. Typically, a semiconductor including silicon, a semiconductor including gallium arsenide, or an oxide semiconductor including indium can be used.

Here, a case where a transistor having a bottom gate structure is manufactured as the transistor 203 and the transistor 206 is shown, and the semiconductor layer 231 includes an oxide semiconductor layer. The transistor 205 has a structure in which a conductive layer 223 and an insulating layer 212 are added to the transistor 203 and the transistor 206, and includes two gate electrodes.

As the semiconductor of the transistor, an oxide semiconductor is preferably used. By using a semiconductor material having a wider band gap than silicon and a smaller carrier density than silicon, the off-state current of the transistor can be reduced.

Specifically, first, a conductive layer 221a, a conductive layer 221b, and a conductive layer 221c are formed on the insulating layer 220. The conductive layer 221a, the conductive layer 221b, and the conductive layer 221c may be formed by forming a photoresist mask after forming a conductive film, etching the conductive film, and then removing the photoresist mask. Here, through the opening of the insulating layer 220, the conductive layer 221b and the electrode 311b and the conductive layer 221c and the conductive layer 311d are connected.

Next, an insulating layer 211 is formed.

As the insulating layer 211, for example, an inorganic insulating film such as a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or an aluminum nitride film can be used. In addition, a hafnium oxide film, a yttrium oxide film, a zirconia film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, a neodymium oxide film, or the like can also be used. Alternatively, a stack of two or more of the insulating films may be used.

Since the inorganic insulating film becomes a dense and highly barrier film at a high film forming temperature, it is preferably formed at a high temperature. The substrate temperature when forming the inorganic insulating film is preferably room temperature (25 ° C) or higher and 350 ° C or lower, and more preferably 100 ° C or higher and 300 ° C or lower.

Next, a semiconductor layer 231 is formed. In this embodiment, an oxide semiconductor layer is formed as the semiconductor layer 231. The oxide semiconductor layer may be formed by forming a photoresist mask after forming the oxide semiconductor film, etching the oxide semiconductor film, and then removing the photoresist mask.

The substrate temperature when forming the oxide semiconductor film is preferably 350 ° C or lower, more preferably room temperature or higher and 200 ° C or lower, and still more preferably room temperature or higher and 130 ° C or lower. In addition, when the substrate temperature is lower than the heating temperature when the resin layer 62 is formed, the influence of degassing from the resin layer 62 can be reduced, which is preferable. Note that the same applies to the case where the insulating layer 220 is formed using a resin.

The oxide semiconductor film can be formed using one of an inert gas and an oxygen gas. Note that there is no particular limitation on the oxygen flow rate (oxygen partial pressure) when the oxide semiconductor film is formed. However, when a transistor having a high field-effect mobility is to be obtained, the oxygen flow rate (oxygen partial pressure) when forming the oxide semiconductor film is preferably 0% or more and 30% or less, more preferably 5% or more and 30% or less, more preferably 7% or more and 15% or less.

The oxide semiconductor film preferably contains at least indium or zinc. It is particularly preferable to include indium and zinc.

The energy gap of the oxide semiconductor is preferably 2 eV or more, more preferably 2.5 eV or more, and even more preferably 3 eV or more. In this way, by using an oxide semiconductor with a wide energy gap, the off-state current of the transistor can be reduced.

The oxide semiconductor film can be formed by a sputtering method. In addition, for example, a PLD method, a PECVD method, a thermal CVD method, an ALD method, or a vacuum evaporation method can be used.

Note that an example of an oxide semiconductor is described in Embodiment Mode 4.

Next, a conductive layer 222a and a conductive layer 222b are formed. The conductive layer 222a and the conductive layer 222b can be formed by forming a photoresist mask after forming a conductive film, etching the conductive film, and then removing the photoresist mask. Both the conductive layer 222a and the conductive layer 222b are connected to the semiconductor layer 231. Here, the conductive layer 222a of the transistor 206 is electrically connected to the conductive layer 221b. Accordingly, in the connection portion 207, the electrode 311b and the conductive layer 222a can be electrically connected.

When the conductive layer 222a and the conductive layer 222b are processed, a part of the semiconductor layer 231 that is not covered by the photoresist mask may be thinned by an etching process.

Through the above steps, the transistor 206 can be manufactured (FIG. 8A). In the transistor 206, a part of the conductive layer 221a is used as a gate, a part of the insulating layer 211 is used as a gate insulating layer, and the conductive layer 222a and the conductive layer 222b are used as a source or a drain, respectively. The transistor 203 may be formed in the same manner.

Next, an insulating layer 212 covering the transistor 206 is formed, and a conductive layer 223 is formed on the insulating layer 212.

The insulating layer 212 can be formed by the same method as the insulating layer 211.

The conductive layer 223 of the transistor 205 may be formed by forming a photoresist mask after forming a conductive film, etching the conductive film, and then removing the photoresist mask.

Through the above steps, the transistor 205 can be manufactured (FIG. 8A). In the transistor 205, a part of the conductive layer 221a and a part of the conductive layer 223 are used as a gate, a part of the insulating layer 211 and a part of the insulating layer 212 are used as a gate insulating layer, and the conductive layer 222a and the conductive layer 222b are respectively Used as a source or sink.

Next, an insulating layer 213 is formed (FIG. 8A). The insulating layer 213 can be formed by the same method as the insulating layer 211.

As the insulating layer 212, an oxide insulating film such as a silicon oxide film or a silicon oxynitride film formed in an atmosphere containing oxygen is preferably used. In addition, as the insulating layer 213, an insulating film such as a silicon nitride film or a silicon oxynitride film, which is difficult to diffuse and transmit oxygen, is preferably laminated on the silicon oxide film or the silicon oxynitride film. The oxide insulating film formed under an atmosphere containing oxygen may be an insulating film that easily releases a large amount of oxygen by heating. Oxygen can be supplied to the oxide semiconductor layer by performing a heat treatment in a state where such an oxide insulating film that releases oxygen and an insulating film that does not easily diffuse and permeate oxygen are laminated together. As a result, oxygen defects in the oxide semiconductor layer and defects in the interface between the oxide semiconductor layer and the insulating layer 212 can be filled, so that the defect energy level can be reduced. Thereby, a highly reliable display device can be realized.

Next, a color layer 134 is formed on the insulating layer 213 (FIG. 8A), and then an insulating layer 214 is formed (FIG. 8B). The color layer 134 is arranged so as to overlap the opening 451 of the electrode 311b.

The color layer 134 can be formed by the same method as the color layer 131. Since the insulating layer 214 is a layer having a formation surface of a display element to be formed later, it is preferably used as a planarization layer. As the insulating layer 214, a resin or an inorganic insulating film that can be used for the insulating layer 121 can be used.

Next, an opening is formed in the insulating layer 212, the insulating layer 213, and the insulating layer 214 to reach the conductive layer 222b of the transistor 205.

Next, an electrode 191 is formed (FIG. 8B). The electrode 191 can be formed by forming a photoresist mask after forming a conductive film, etching the conductive film, and then removing the photoresist mask. Here, the conductive layer 222b of the transistor 205 is connected to the electrode 191. The electrode 191 is formed using a conductive material that transmits visible light.

Next, an insulating layer 216 is formed to cover the ends of the electrode 191 (FIG. 9A). As the insulating layer 216, a resin or an inorganic insulating film that can be used for the insulating layer 121 can be used. The insulating layer 216 has an opening in a portion overlapping the electrode 191.

Next, an EL layer 192 and an electrode 193 are formed (FIG. 9A). A part of the electrode 193 is used as a common electrode of the light emitting element 170. The electrode 193 is formed using a conductive material that reflects visible light.

The EL layer 192 can be formed by a method such as a vapor deposition method, a coating method, a printing method, or a spray method. When forming the EL layer 192 for each pixel, a vapor deposition method or an inkjet method using a shadow mask such as a metal mask can be used. When the EL layer 192 is not formed for each pixel, a vapor deposition method without using a metal mask can be used.

As the EL layer 192, a low-molecular compound or a high-molecular compound may be used, and an inorganic compound may be further included.

In each process performed after the EL layer 192 is formed, the temperature for heating the EL layer 192 must be equal to or lower than the heat-resistant temperature of the EL layer 192. The electrode 193 can be formed by a vapor deposition method, a sputtering method, or the like.

Through the above process, the light emitting element 170 can be formed (FIG. 9A). The light-emitting element 170 has a structure in which an electrode 191, a portion of which is used as a pixel electrode, an EL layer 192, and an electrode 193, which is a portion used as a common electrode, are stacked. The light-emitting element 170 is manufactured such that its light-emitting region overlaps with the color layer 134 and the opening 451 in the electrode 311 b.

Although an example of manufacturing a bottom emission type light emitting element as the light emitting element 170 is shown here, one embodiment of the present invention is not limited thereto.

The light emitting element has a top emission structure, a bottom emission structure, or a double-sided emission structure. As the electrode on the light extraction side, a conductive film that transmits visible light is used. In addition, it is preferable to use a conductive film that reflects visible light as the electrode that does not extract light.

Next, an insulating layer 194 is formed so as to cover the electrode 193 (FIG. 9A). The insulating layer 194 is used as a protective layer that suppresses the diffusion of impurities such as water to the light emitting element 170. The light emitting element 170 is sealed by an insulating layer 194. After the electrode 193 is formed, the insulating layer 194 is preferably formed so as not to be exposed to the atmosphere.

As the insulating layer 194, for example, the inorganic insulating film that can be used for the insulating layer 121 can be used. In particular, it is preferable to use an inorganic insulating film having high barrier properties. Alternatively, a laminate of an inorganic insulating film and an organic insulating film may be used.

The substrate temperature when the insulating layer 194 is formed is preferably a temperature equal to or lower than the heat-resistant temperature of the EL layer 192. The insulating layer 194 can be formed by an ALD method, a sputtering method, or the like. The ALD method and the sputtering method are preferable because they can form a film at a low temperature. When the ALD method is used, the coverage of the insulating layer 194 is high, so it is preferable.

Next, the substrate 351 is bonded to the surface of the insulating layer 194 using the adhesive layer 142 (FIG. 9B).

As the adhesive layer 142, various hardening adhesives, such as a light hardening adhesive, such as an ultraviolet hardening adhesive, a reaction hardening adhesive, a thermosetting adhesive, and an anaerobic adhesive, can be used. Alternatively, an adhesive sheet or the like may be used.

As the substrate 351, for example, a polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), a polyacrylonitrile resin, an acrylic resin, or a polyethylene resin can be used. Amine resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyether resin (PES) resin, polyamine resin (nylon, aromatic polyamine, etc.), polysiloxane resin, cycloolefin Resin, polystyrene resin, polyamido-imino resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, and cellulose Rice fiber and so on. As the substrate 351, various materials such as glass, quartz, resin, metal, alloy, or semiconductor can be used. As the substrate 351, various materials such as glass, quartz, resin, metal, alloy, or semiconductor whose thickness is allowed to be used can also be used.

Next, the resin layer 62 is irradiated with laser light through the manufacturing substrate 61.

The resin layer 62 is embrittled by laser irradiation. Alternatively, the tightness between the resin layer 62 and the manufacturing substrate 61 is reduced by laser irradiation.

At least a part of the laser light is transmitted through the manufacturing substrate 61, and light of a wavelength absorbed by the resin layer 62 is selectively used. The laser is preferably light in a wavelength range from visible rays to ultraviolet rays. For example, light having a wavelength of 200 nm to 400 nm can be used, and preferably light having a wavelength of 250 nm to 350 nm is used. In particular, when an excimer laser having a wavelength of 308 nm is used, it is preferable because it is excellent in productivity. Since excimer lasers can be used for laser crystallization in LTPS, conventional LTPS production line devices can be used, and no new equipment investment is required, so it is preferred. In addition, a solid UV laser (also referred to as a semiconductor UV laser), such as a UV laser having a wavelength of 355 nm of the third harmonic of the Nd: YAG laser, may be used. Since a solid laser does not use a gas, it can achieve about one-third of the operating cost compared to an excimer laser, so it is preferable. Alternatively, a pulsed laser such as a picosecond laser may be used.

When a linear laser is used as the laser, the laser is scanned by moving the manufacturing substrate 61 relative to the light source, and the laser is irradiated along the area to be peeled.

Since a solid laser does not use a gas, it can achieve about one-third of the operating cost compared to an excimer laser, so it is preferable.

Next, the manufacturing substrate 61 is separated from the insulating layer 63 (FIG. 10A). FIG. 10A illustrates an example where separation occurs in the resin layer 62. A part of the resin layer (resin layer 62a) remains on the manufacturing substrate 61. The thickness of the resin layer 62b remaining on the insulating layer 31 side is thinner than the resin layer 62 of FIG. 10A.

The position of the separation surface may change depending on the materials and forming methods of the resin layer 62 and the manufacturing substrate 61, and the conditions of light irradiation.

Although FIG. 10A shows an example where separation occurs in the resin layer 62, separation may occur in the resin layer 62 and the interface between the insulating layer 63 and the resin layer 62 in some cases. A part of the resin layer (resin layer 62a) remains on the manufacturing substrate 61. By performing the separation, the insulating layer 63 is exposed. The thickness of the resin layer 62b remaining on the insulating layer 63 side is thinner than the resin layer 62 of FIG. 9B.

In addition, there are cases where separation occurs in the interface between the manufacturing substrate 61 and the resin layer 62 and the separation resin layer 62 is exposed by performing separation; and cases where separation occurs in the resin layer 62.

As described above, by forming the conductive layer 311 c in the recessed portion of the resin layer 62, the conductive layer 311 c is easily exposed. In addition, since the insulating layer 63 and / or the resin layer 62b can be left after the conductive layer 311c is exposed, contamination of the transistor can be suppressed.

The thickness of the resin layer 62 a remaining on the manufacturing substrate 61 side may be, for example, 100 nm or less, and specifically, may be about 40 nm or more and about 70 nm or less. By removing the resin layer 62a, the manufacturing substrate 61 can be reused. For example, when glass is used for manufacturing the substrate 61 and polyimide resin is used for the resin layer 62, the resin layer 62a may be removed using fuming nitric acid or the like. In addition, the resin layer 62 may be formed on the resin layer 62 a remaining on the manufacturing substrate 61 by using a material having photosensitivity and thermosetting property again.

For example, the substrate 61 may be peeled off by applying a force in the vertical direction to the resin layer 62. Specifically, the manufacturing substrate 61 can be peeled off by stretching a part of the top surface of the suction substrate 351 upward. In this case, it is preferable to insert a sharp-shaped device such as a cutter between the manufacturing base plate 61 and the insulating layer 63 to form a separation starting point.

In this embodiment, since the conductive layer 311c is not exposed when separated from the manufacturing substrate 61, at least a part of the resin layer 62b and the insulating layer 63 is further removed from the remaining structure of the insulating layer 63 and the resin layer 62b. The conductive layer 311c is exposed (FIG. 10B).

The method of removing the resin layer 62 is not particularly limited. For example, a wet etching method, a dry etching method, or the like may be used, but the resin layer 62 is preferably removed by ashing using an oxygen plasma. Ashing has the following advantages: high controllability; good in-plane uniformity; and suitable for processing using large substrates. The insulating layer 63 can be removed, for example, by a dry etching method or the like.

Next, an alignment film 133a is formed on the surface of the exposed electrode 311a (FIG. 11). The alignment film 133a can be formed by performing a rubbing treatment after forming a thin film such as a resin. Note that although an alignment film is provided separately in this embodiment, the remaining resin layer 62b may be subjected to a rubbing treatment to use it as an alignment film.

Then, the substrate 351 that has completed the steps up to the formation of the alignment film 133a and the substrate 361 that has completed the steps up to FIG. 7A are bonded together via the liquid crystal 112 using the adhesive layer 141 (FIG. 11). The adhesive layer 141 can be formed using a material that can be used for the adhesive layer 142.

The liquid crystal element 180 shown in FIG. 11 has a structure in which an electrode 311 a (and an electrode 311 b) of which a part is used as a pixel electrode, a liquid crystal 112 and an electrode 113 of which a part is used as a common electrode are stacked. The liquid crystal element 180 is manufactured so as to overlap the color layer 131.

As described above, the display device 300 can be manufactured.

12A to 16 are diagrams showing different structures of the display device 300. 12A to 16 are substantially the same as FIGS. 7A to 11, but the method of forming the recessed portion of the insulating layer 62 is different, so the shape of the insulating layer 63 is different. As a manufacturing method, the insulating layer 63 is formed after the resin layer 62 is formed and before the recessed portion is formed (FIG. 12B). Then, the insulating layer 63 and the resin layer 62 are simultaneously etched, thereby forming a recessed portion (FIG. 12C). After the insulating layer 63 is opened, the above-mentioned etching may be completed with the resin layer 62 remaining. Thereby, the resin layer 62 which has a recessed part can be formed. As this etching, dry etching can be used. At this time, the resin layer 62 can be formed using a material having no photosensitivity.

In addition, as shown in FIG. 17A, the entire resin layer 62 may be removed. At this time, it is preferable because the conductive layer 311c protrudes and the anchoring effect is generated by providing the connection layer 242 so as to cover the conductive layer 311c. This can improve the tightness between the connection layer 242 and the conductive layer 311c (FIG. 18). Note that a structure in which the conductive layer 311c is protruded in a state where the resin layer 62 remains may be adopted.

19A to 23 are diagrams showing different structures of the display device 300. 19A to FIG. 23 are substantially the same as FIGS. 7A to 11 except that the insulating layer 63 is not formed in FIGS. 19A to 23. As a manufacturing method, after the resin layer 62 is formed, the recessed portion is formed without forming the insulating layer 63 (FIGS. 19B and 19C), and the electrode 311 a and the conductive layer 311 c (FIG. 19D) may be formed. After the substrate 61 is manufactured separately, the resin layer 62b is removed, thereby exposing the conductive layer 311c. By not forming the insulating layer 63, the formation process or the removal process can be omitted.

As described above, the display device that can be easily manufactured by this embodiment includes two display elements and can be used by switching a plurality of display modes. Therefore, a display device having high visibility and convenience can be realized regardless of the surrounding brightness.

This embodiment can be combined with other embodiments as appropriate. In addition, in this specification, when a plurality of structural examples are shown in one embodiment, the structural examples may be appropriately combined.

    Embodiment 2    

In this embodiment mode, a display device that can be manufactured by one embodiment of the invention will be described with reference to FIGS. 24 to 27C.

FIG. 24 shows a block diagram of the display device 10. The display device 10 includes a display portion 14.

The display unit 14 includes a plurality of pixel units 30 arranged in a matrix. The pixel unit 30 includes a first pixel 31p and a second pixel 32p.

FIG. 24 shows an example in which the first pixel 31 p and the second pixel 32 p each include three color display elements corresponding to red (R), green (G), and blue (B).

The display elements included in the first pixel 31p are all display elements using reflection of external light. The first pixel 31p includes a first display element 31R corresponding to red (R), a first display element 31G corresponding to green (G), and a first display element 31B corresponding to blue (B).

The display elements included in the second pixel 32p are all light emitting elements. The second pixel 32p includes a second display element 32R corresponding to red (R), a second display element 32G corresponding to green (G), and a second display element 32B corresponding to blue (B).

25A to 25C are diagrams illustrating a configuration example of the pixel unit 30.

The first pixel 31p includes a first display element 31R, a first display element 31G, and a first display element 31B. The first display element 31R reflects external light and emits red light Rr to the display surface side. Similarly, the first display element 31G and the first display element 31B also emit green light Gr and blue light Br to the display surface side, respectively.

The second pixel 32p includes a second display element 32R, a second display element 32G, and a second display element 32B. The second display element 32R emits red light Rt to the display surface side. Similarly, the second display element 32G and the second display element 32B also emit green light Gt and blue light Bt to the display surface side, respectively.

FIG. 25A corresponds to a mode (third mode) in which display is performed by driving both the first pixel 31p and the second pixel 32p. In the pixel unit 30, by using reflected light (light Rr, light Gr, light Br) and transmitted light (light Rt, light Gt, light Bt), light 35tr of a predetermined color can be emitted to the display surface side.

FIG. 25B corresponds to a mode (first mode) for performing display using reflected light by driving only the first pixel 31p. In the pixel unit 30, for example, when the external light is sufficiently strong, only the light (light Rr, light Gr, and light Br) from the first pixel 31p is used without driving the second pixel 32p, so that the light 35r can be emitted. Go to the display side. This enables driving with extremely low power consumption.

FIG. 25C corresponds to a mode (second mode) for performing display using light emission (transmitted light) by driving only the second pixel 32p. In the pixel unit 30, for example, when the external light is extremely weak, only the light (light Rt, light Gt, and light Bt) from the second pixel 32p is used without driving the first pixel 31p, so that the light 35t can be emitted. Go to the display side. Thereby, a clear display can be performed. In addition, by reducing the brightness when the surroundings are dim, it is possible to reduce power consumption while suppressing the glare felt by the user.

There are no restrictions on the color or number of display elements included in the first pixel 31p and the second pixel 32p.

26A to 26C and 27A to 27C illustrate a configuration example of the pixel unit 30. Note that although a schematic diagram corresponding to a mode (third mode) in which display is performed by driving both the first pixel 31p and the second pixel 32p is shown here, as in the above description, it is also possible to drive only Display is performed in the first pixel 31p or the second pixel 32p mode (first mode and second mode).

The second pixel 32p shown in FIGS. 26A, 26C, and 27B includes a second display element 32W that displays white (W) in addition to the second display element 32R, second display element 32G, and second display element 32B.

The second pixel 32p shown in FIGS. 26B and 27C includes a second display element 32Y showing a yellow (Y) in addition to the second display element 32R, the second display element 32G, and the second display element 32B.

Compared to the structure not including the second display element 32W and the second display element 32Y, the structure shown in FIGS. 26A to 26C, 27A, and 27B can reduce the display mode using the second pixel 32p (the second mode and the Three modes) required power consumption.

The first pixel 31p shown in FIG. 26C includes a first display element 31W that exhibits white (W) in addition to the first display element 31R, the first display element 31G, and the first display element 31B.

Compared with the structure shown in FIG. 25A, the structure shown in FIG. 26C can reduce the power consumption required for the display mode (first mode and third mode) using the first pixel 31p.

The first pixel 31p shown in FIGS. 27A to 27C includes only the first display element 31W that appears white. At this time, in a display mode (first mode) using only the first pixel 31p, black and white display or gray level display can be performed, and in a display mode (second mode and third mode) using the second pixel 32p, it is possible to Perform color display.

By adopting this structure, the aperture ratio of the first pixel 31p can be increased, so that the reflectance of the first pixel 31p can be increased, and a brighter image can be displayed.

The first mode is suitable for displaying information that does not require color display, such as document information.

This embodiment can be implemented in appropriate combination with other embodiments.

    Embodiment 3    

In this embodiment mode, a more specific configuration example of the display device described in Embodiment Mode 1 will be described with reference to FIGS. 28A to 30B.

FIG. 28A is a block diagram of the display device 400. The display device 400 includes a display portion 362, a circuit GD, and a circuit SD. The display section 362 includes a plurality of pixels 410 arranged in a matrix.

The display device 400 includes multiple wirings G1, multiple wirings G2, multiple wirings ANO, multiple wirings CSCOM, multiple wirings S1, and multiple wirings S2. The plurality of wirings G1, the plurality of wirings G2, the plurality of wirings ANO, and the plurality of wirings CSCOM are each electrically connected to a plurality of pixels 410 and a circuit GD arranged in a direction indicated by an arrow R. The plurality of wirings S1 and the plurality of wirings S2 are electrically connected to a plurality of pixels 410 and a circuit SD arranged in a direction indicated by an arrow C, respectively.

Note that although a structure including one circuit GD and one circuit SD is shown here for simplicity, a circuit GD and a circuit SD for driving a liquid crystal element and a circuit GD and a circuit SD for driving a light emitting element may be provided separately.

The pixel 410 includes a reflective liquid crystal element and a light emitting element.

28B1 to 28B4 illustrate a configuration example of an electrode 311 included in the pixel 410. The electrode 311 is used as a reflective electrode of a liquid crystal element. An opening 451 is provided in the electrode 311 of FIGS. 28B1 and 28B2.

In FIGS. 28B1 and 28B2, the light-emitting element 360 located in a region overlapping with the electrode 311 is shown by a dotted line. The light emitting element 360 overlaps the opening 451 included in the electrode 311. Accordingly, the light emitted from the light emitting element 360 is emitted to the display surface side through the opening 451.

In Fig. 28B1, the pixels 410 adjacent in the direction indicated by the arrow R are pixels corresponding to different colors. At this time, as shown in FIG. 28B1, it is preferable that the openings 451 in the two pixels adjacent in the direction indicated by the arrow R are provided at different positions of the electrode 311 so as not to be arranged in a row. Thereby, the two light emitting elements 360 can be arranged separately, so that a phenomenon (also referred to as crosstalk) in which light emitted by the light emitting elements 360 enters a color layer included in an adjacent pixel 410 can be suppressed. In addition, since two adjacent light-emitting elements 360 can be arranged separately, even if the EL layer of the light-emitting element 360 is separately manufactured using a shadow mask or the like, a high-resolution display device can be realized.

In FIG. 28B2, the pixels 410 adjacent in the direction indicated by the arrow C are pixels corresponding to different colors. 28B2 is the same, and it is preferable that the openings 451 in two pixels adjacent to each other in the direction indicated by the arrow C are provided at different positions of the electrode 311 so as not to be arranged in a row.

The smaller the ratio of the total area of the opening 451 to the total area of the non-opening portion, the brighter the display using the liquid crystal element can be. In addition, the larger the ratio of the total area of the opening 451 to the total area of the non-opening portion, the brighter the display using the light-emitting element 360 can be.

The shape of the opening 451 may be, for example, a polygonal shape, a quadrangular shape, an oval shape, a circular shape, or a cross shape. In addition, the shape may be an elongated strip shape, a slit shape, or a checkered shape. In addition, the opening 451 may be arranged so as to be close to an adjacent pixel. Preferably, the opening 451 is arranged close to other pixels displaying the same color. This can suppress the occurrence of crosstalk.

In addition, as shown in FIGS. 28B3 and 28B4, the light-emitting area of the light-emitting element 360 may be located at a portion where the electrode 311 is not provided. Thereby, the light emitted from the light emitting element 360 is emitted to the display surface side.

In FIG. 28B3, among the two pixels 410 adjacent to each other in the direction indicated by the arrow R, the light emitting elements 360 are not arranged in a row. In FIG. 28B4, among two pixels adjacent to each other in a direction indicated by an arrow R, the light emitting elements 360 are disposed on one column.

As the circuit GD, various sequential circuits such as a shift register can be used. As the circuit GD, a transistor, a capacitor, or the like can be used. The transistor included in the circuit GD can be formed by the same process as the transistor included in the pixel 410.

The circuit SD is electrically connected to the wiring S1. For example, an integrated circuit can be used as the circuit SD. Specifically, as the circuit SD, an integrated circuit formed on a silicon substrate can be used.

For example, the circuit SD may be mounted on a pad electrically connected to the pixel 410 by using a COG (Chip on glass) method or a COF method. Specifically, an anisotropic conductive film can be used to mount the integrated circuit on the pad.

FIG. 29 is an example of a circuit diagram of the pixel 410. FIG. 29 illustrates two adjacent pixels 410.

The pixel 410 includes a switch SW1, a capacitor C1, a liquid crystal element 340, a switch SW2, a transistor M, a capacitor C2, a light emitting element 360, and the like. The wiring G1, the wiring G2, the wiring ANO, the wiring CSCOM, the wiring S1, and the wiring S2 are electrically connected to the pixel 410. In addition, FIG. 29 shows a wiring VCOM1 electrically connected to the liquid crystal element 340 and a wiring VCOM2 electrically connected to the light emitting element 360.

FIG. 29 shows an example when a transistor is used for the switches SW1 and SW2.

The gate of the switch SW1 is connected to the wiring G1. One of the source and the drain of the switch SW1 is connected to the wiring S1, and the other is connected to one electrode of the capacitor C1 and one electrode of the liquid crystal element 340. The other electrode of the capacitor C1 is connected to the wiring CSCOM. The other electrode of the liquid crystal element 340 is connected to the wiring VCOM1.

The gate of the switch SW2 is connected to the wiring G2. One of the source and the drain of the switch SW2 is connected to the wiring S2, and the other is connected to one electrode of the capacitor C2 and the gate of the transistor M. The other electrode of the capacitive element C2 is connected to one of the source and the drain of the transistor M and the wiring ANO. The other of the source and the drain of the transistor M is connected to one electrode of the light emitting element 360. The other electrode of the light emitting element 360 is connected to the wiring VCOM2.

FIG. 29 shows an example in which the transistor M includes two gates connected to each other with a semiconductor interposed therebetween. As a result, the amount of current that the transistor M can flow can be increased.

The wiring G1 may be supplied with a signal to control the switch SW1 to a conductive state or a non-conductive state. A predetermined potential can be supplied to the wiring VCOM1. The wiring S1 may be supplied with a signal that controls the alignment state of the liquid crystal included in the liquid crystal element 340. A predetermined potential can be supplied to the wiring CSCOM.

The wiring G2 may be supplied with a signal to control the switch SW2 to a conductive state or a non-conductive state. Each of the wiring VCOM2 and the wiring ANO may be supplied with a potential that generates a potential difference for causing the light-emitting element 360 to emit light. A signal for controlling the on-state of the transistor M may be supplied to the wiring S2.

The pixel 410 shown in FIG. 29 can be driven by signals supplied to the wiring G1 and the wiring S1 when the display is performed in the reflection mode, and can be displayed by optical modulation of the liquid crystal element 340. When the display is performed in the transmissive mode, the display device can be driven by a signal supplied to the wiring G2 and the wiring S2 to cause the light-emitting element 360 to emit light for display. In addition, when driving in two modes, it is possible to drive using signals supplied to the wiring G1, the wiring G2, the wiring S1, and the wiring S2, respectively.

Note that although FIG. 29 shows an example in which one pixel 410 includes one liquid crystal element 340 and one light emitting element 360, it is not limited thereto. FIG. 30A shows an example in which one pixel 410 includes one liquid crystal element 340 and four light emitting elements 360 (light emitting elements 360r, 360g, 360b, and 360w). Unlike FIG. 29, the pixel 410 shown in FIG. 30A can perform full-color display using a light-emitting element with one pixel.

In FIG. 30A, in addition to the configuration example of FIG. 29, the wiring G3 and the wiring S3 are connected to the pixel 410.

In the example shown in FIG. 30A, for example, as the four light-emitting elements 360, light-emitting elements that exhibit red (R), green (G), blue (B), and white (W) can be used. As the liquid crystal element 340, a white reflective liquid crystal element can be used. Therefore, when the display is performed in the reflective mode, a white display with a high reflectance can be performed. In addition, when displaying in the transmission mode, high color rendering can be performed with low power consumption.

FIG. 30B shows a configuration example of the pixel 410 corresponding to FIG. 30A. The pixel 410 includes a light-emitting element 360w overlapping the opening included in the electrode 311, a light-emitting element 360r, a light-emitting element 360g, and a light-emitting element 360b arranged around the electrode 311. The light emitting elements 360r, 360g, and 360b preferably have almost the same light emitting area.

This embodiment can be combined with other embodiments as appropriate.

    Embodiment 4    

In this embodiment, a configuration of a CAC (Cloud-Aligned Composite) -OS in a transistor disclosed in one embodiment of the present invention will be described.

CAC-OS refers to, for example, a structure of a material in which elements constituting an oxide semiconductor are unevenly distributed in a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less. Note that, in the following, one or more metal elements are unevenly distributed in the oxide semiconductor and the regions containing the metal elements are mixed in a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less. The state is called mosaic or patch.

The oxide semiconductor preferably contains at least indium. In particular, it is preferable to contain indium and zinc. In addition, it can also contain aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, praseodymium, tantalum, tungsten And one or more of magnesium and the like.

For example, CAC-OS in In-Ga-Zn oxide (In CAC-OS, In-Ga-Zn oxide may be referred to as CAC-IGZO in particular) means that the material is divided into indium oxide (hereinafter, referred to as InO _X1 (X1 is a real number greater than 0)) or indium zinc oxide (hereinafter referred to as In _X2 Zn _Y2 O _Z2 (X2, Y2 and Z2 are real numbers greater than 0)) and gallium oxide (hereinafter referred to as GaO _X3 (X3 is a real number greater than 0)) or gallium zinc oxide (hereinafter referred to as Ga _X4 Zn _Y4 O _Z4 (X4, Y4, and Z4 are real numbers greater than 0)), etc., and become mosaic-like, and mosaic-like InO _X1 Or a structure in which In _X2 Zn _Y2 O _{Z2 is} uniformly distributed in the film (hereinafter, also referred to as a cloud shape).

In other words, CAC-OS is a composite oxide semiconductor having a structure in which a region containing GaO _X3 as a main component and a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component are mixed together. In this specification, for example, when the ratio of In to the element M in the first region is larger than the ratio of In to the element M in the second region, the In concentration in the first region is higher than that in the second region.

Note that IGZO is a generic term and sometimes refers to a compound containing In, Ga, Zn, and O. As typical examples, InGaO ₃ (ZnO) _m1 (m1 is a natural number) or In _{(1 + x0)} Ga _(1-x0) O ₃ (ZnO) _m0 (-1 x0 1, m0 is an arbitrary number).

The crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. The CAAC structure is a crystalline structure in which a plurality of nanocrystals of IGZO have c-axis alignment and are connected in a non-alignment manner on the a-b plane.

On the other hand, CAC-OS is related to the material composition of an oxide semiconductor. CAC-OS refers to a structure in which, in a material composition including In, Ga, Zn, and O, a nano-particle region having Ga as a main component is observed in a part and a nano-component having In as a main component is observed in a part. The granular regions are randomly dispersed in a mosaic shape. Therefore, in CAC-OS, the crystal structure is a secondary factor.

CAC-OS does not include a laminated structure of two or more films having different compositions. For example, a structure including two layers of a film containing In as a main component and a film containing Ga as a main component is not included.

Note that a clear boundary between a region containing GaO _X3 as a main component and a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component may not be observed in some cases.

CAC-OS contains a material selected from the group consisting of aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, thorium, tantalum, tungsten, and magnesium In the case where one or more types are substituted for gallium, CAC-OS refers to a structure in which a nano-particle region having the element as a main component is observed in a part and a nano-particle region having In as a main component is observed in a part. Spread irregularly in a mosaic pattern.

CAC-OS can be formed by, for example, a sputtering method without intentionally heating the substrate. In the case where CAC-OS is formed by a sputtering method, as the deposition gas, one or more selected from an inert gas (typically argon), an oxygen gas, and a nitrogen gas can be used. In addition, the lower the oxygen gas flow ratio in the total flow of the deposition gas during film formation, the better. For example, the oxygen gas flow ratio is set to 0% or more and less than 30%, preferably 0% or more and 10 %the following.

CAC-OS has a characteristic that when a measurement is performed by θ / 2θ scan by an out-of-plane method based on one of X-ray diffraction (XRD: X-ray diffraction) measurement methods, a clear peak is not observed. That is, it can be seen from the X-ray diffraction that there is no alignment in the a-b plane direction and the c-axis direction in the measurement area.

In addition, in the electron diffraction pattern of CAC-OS obtained by irradiating an electron beam (also referred to as a nanobeam) having a beam diameter of 1 nm, a ring-shaped region with high brightness was observed in the ring-shaped region. Multiple highlights. From this, it can be seen from the electron diffraction pattern that the crystal structure of the CAC-OS has an nc (nano-crystal) structure with no orientation in the planar direction and the cross-sectional direction.

In addition, for example, in the CAC-OS of the In-Ga-Zn oxide, based on an EDX surface analysis image obtained by Energy Dispersive X-ray spectroscopy (EDX), it can be confirmed that: A region in which GaO _X3 is a main component and a region in which In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component are unevenly distributed and mixed.

CAC-OS has a different structure from IGZO compounds in which metal elements are uniformly distributed, and has different properties from IGZO compounds. In other words, CAC-OS has a mosaic-like structure in which a region including GaO _X3 and the like as a main component and a region including In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component are separated from each other and a region including each element as a main component.

Here, the region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as the main component has higher conductivity than the region containing GaO _X3 or the like as the main component. In other words, when a carrier flows through a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component, the conductivity of the oxide semiconductor is exhibited. Therefore, when a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component is distributed in a cloud shape in the oxide semiconductor, a high field-effect mobility (μ) can be achieved.

On the other hand, regions having GaO _X3 or the like as a main component have higher insulation properties than regions having In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component. In other words, when a region having GaO _X3 or the like as a main component is distributed in the oxide semiconductor, a leakage current can be suppressed and a good switching operation can be achieved.

Therefore, when CAC-OS is used for a semiconductor device, a high on-state current (I _on ) can be achieved by the complementary effects of the insulation due to GaO _X3 and the like and the conductivity due to In _X2 Zn _Y2 O _Z2 or InO _X1 . And high field effect mobility (μ).

In addition, a semiconductor element using CAC-OS has high reliability. Therefore, CAC-OS is suitable for various semiconductor devices such as displays.

This embodiment can be combined with other embodiments as appropriate.

    Embodiment 5    

In this embodiment, a display module and an electronic device according to an embodiment of the present invention will be described.

The display module 8000 shown in FIG. 31 includes a touch panel 8004 connected to the FPC 8003, a display panel 8006 connected to the FPC 8005, a frame 8009, a printed circuit board 8010, and a battery 8011 between the upper cover 8001 and the lower cover 8002.

The display device according to one embodiment of the present invention can be used for the display panel 8006, for example. This makes it possible to manufacture a display module having high visibility regardless of the surrounding brightness. In addition, a display module with low power consumption can be manufactured. In addition, a display module with a wide viewing angle can be manufactured.

The upper cover 8001 and the lower cover 8002 can be appropriately changed in shape or size according to the sizes of the touch panel 8004 and the display panel 8006.

As the touch panel 8004, a resistive film type touch panel or an electrostatic capacity type touch panel which is superimposed on the display panel 8006 can be used. In addition, the display panel 8006 may be provided with a touch panel function without providing the touch panel 8004.

The frame 8009 has a function of shielding the electromagnetic wave generated by the operation of the printed circuit board 8010 in addition to the function of protecting the display panel 8006. In addition, the frame 8009 may have a function of a heat sink.

The printed circuit board 8010 includes a power circuit and a signal processing circuit for outputting video signals and clock signals. As a power source for supplying power to the power supply circuit, an external commercial power source or a power source of a battery 8011 separately provided may be used. When using a commercial power source, the battery 8011 can be omitted.

In addition, the display module 8000 may further include components such as a polarizing plate, a retardation plate, and a cymbal.

The display device according to an embodiment of the present invention can achieve high visibility regardless of the intensity of external light. Thereby, it can be suitably applied to a portable electronic device, a wearable electronic device, an e-book reader, and the like.

The portable information terminal 800 shown in FIGS. 32A and 32B includes a casing 801, a casing 802, a display portion 803, a display portion 804, a hinge portion 805, and the like.

The casing 801 and the casing 802 are connected together by a hinge portion 805. The portable information terminal 800 can be switched from the folded state (FIG. 32A) to the expanded state shown in FIG. 32B.

A display device according to an embodiment of the present invention can be used for at least one of the display section 803 and the display section 804. This makes it possible to manufacture a portable information terminal having high visibility regardless of the surrounding brightness. In addition, a portable information terminal with low power consumption can be manufactured. In addition, a portable information terminal with a wide viewing angle can be manufactured.

The display unit 803 and the display unit 804 can display at least one of file information, still images, and moving images. When the document information is displayed on the display section, the portable information terminal 800 can be used as an e-book reader.

The portable information terminal 800 can be folded, so it has high portability and excellent versatility.

The casing 801 and the casing 802 may also include a power button, an operation button, an external port, a speaker, a microphone, and the like.

The portable information terminal 810 shown in FIG. 32C includes a casing 811, a display portion 812, operation buttons 813, an external port 814, a speaker 815, a microphone 816, a camera 817, and the like.

A display device according to an embodiment of the present invention can be used for the display portion 812. This makes it possible to manufacture a portable information terminal having high visibility regardless of the surrounding brightness. In addition, a portable information terminal with low power consumption can be manufactured. In addition, a portable information terminal with a wide viewing angle can be manufactured.

The portable information terminal 810 includes a touch sensor in the display section 812. By touching the display portion 812 with a finger, a stylus, or the like, various operations such as making a call or entering a character can be performed.

In addition, by operating the operation button 813, the power can be turned on or off, or the type of image displayed on the display unit 812 can be switched. For example, you can switch the screen for writing emails to the main menu screen.

In addition, by installing a detection device such as a gyro sensor or an acceleration sensor in the portable information terminal 810, the orientation (vertical or horizontal) of the portable information terminal 810 can be determined, and the screen of the display portion 812 The display direction is automatically switched. In addition, the screen display can be switched by touching the display section 812, operating the operation button 813, or inputting sound using the microphone 816.

The portable information terminal 810 has, for example, one or more functions selected from the group consisting of a telephone, a notebook, and an information reading device. Specifically, the portable information terminal 810 can be used as a smartphone. The portable information terminal 810 can execute various applications such as mobile phones, emails, reading and editing of articles, music playback, animation playback, network communication, and computer games.

The camera 820 shown in FIG. 32D includes a housing 821, a display portion 822, an operation button 823, a shutter button 824, and the like. A detachable lens 826 is attached to the camera 820.

A display device according to an embodiment of the present invention can be used for the display portion 822. By having a display section having high visibility regardless of the surrounding brightness, the convenience of the camera can be improved. In addition, a camera with low power consumption can be manufactured. In addition, a camera with a wide viewing angle can be manufactured.

Here, although the camera 820 has a structure in which the lens 826 can be removed from the housing 821 and exchanged, the lens 826 and the housing 821 may be integrated.

By pressing the shutter button 824, the camera 820 can shoot a still image or a moving image. In addition, the display unit 822 may be provided with a function of a touch panel, and imaging may be performed by touching the display unit 822.

The camera 820 may further include a flash unit, a viewfinder, and the like, which are separately installed. In addition, these members may be assembled in the housing 821.

33A to 33E are diagrams illustrating an electronic device. These electronic devices include a housing 9000, a display 9001, a speaker 9003, an operation key 9005 (including a power switch or an operation switch), a connection terminal 9006, and a sensor 9007 (which has a function of measuring the following factors: force, displacement, position, speed (Acceleration, angular velocity, speed, distance, light, fluid, magnetism, temperature, chemicals, sound, time, hardness, electric field, current, voltage, electricity, radiation, flow, humidity, tilt, vibration, odor, or infrared) , Microphone 9008 and so on.

The display device according to one embodiment of the present invention can be suitably used for the display unit 9001. This makes it possible to manufacture an electronic device including a display portion having high visibility regardless of the brightness of the surroundings. In addition, an electronic device with low power consumption can be manufactured. In addition, an electronic device with a wide viewing angle can be manufactured.

The electronic device shown in FIGS. 33A to 33E may have various functions. For example, it can have the following functions: display various information (still images, moving images, text images, etc.) on the display; touch panel; display calendar, date or time, etc .; control processing by using various software (programs); Perform wireless communication; connect to various computer networks by using wireless communication functions; send or receive various data by using wireless communication functions; read out programs or data stored in storage media and display them on the display Department is superior. Note that the functions of the electronic device shown in FIGS. 33A to 33E are not limited to the functions described above, but may have other functions.

FIG. 33A is a perspective view showing a watch type portable information terminal 9200, and FIG. 33B is a perspective view showing a watch type portable information terminal 9201.

The portable information terminal 9200 shown in FIG. 33A can execute various applications such as mobile phones, emails, reading and editing of articles, music playback, network communication, computer games, and the like. In addition, the display surface of the display unit 9001 is curved, and display can be performed along the curved display surface. In addition, the portable information terminal 9200 can perform short-range wireless communication based on a communication standard. For example, by communicating with a headset capable of wireless communication, a hands-free call can be made. In addition, the portable information terminal 9200 includes a connection terminal 9006, which can directly exchange data with other information terminals through a connector. In addition, charging can also be performed through the connection terminal 9006. In addition, the charging operation can also be performed by wireless power supply without using the connection terminal 9006.

The portable information terminal 9201 shown in FIG. 33B is different from the portable information terminal shown in FIG. 33A in that the display surface of the display portion 9001 is not curved. In addition, the display unit of the portable information terminal 9201 has a non-rectangular shape (a circular shape in FIG. 33B).

33C to 33E are perspective views showing a portable information terminal 9202 that can be folded. 33C is a perspective view of a state where the portable information terminal 9202 is unfolded, and FIG. 33D is a halfway state when the portable information terminal 9202 is switched from one of the unfolded state and the folded state to the other Perspective view, FIG. 33E is a perspective view of a state where the portable information terminal 9202 is folded.

The portable information terminal 9202 has good portability in the folded state, and in the unfolded state, has a large display area because it has a large display area that is seamlessly spliced. The display portion 9001 included in the portable information terminal 9202 is supported by three casings 9000 connected by a hinge 9055. By bending the two housings 9000 by the hinge 9055, the portable information terminal 9202 can be reversibly changed from the unfolded state to the folded state. For example, the portable information terminal 9202 can be bent with a curvature radius of 1 mm or more and 150 mm or less.

This embodiment can be combined with other embodiments as appropriate.

Claims (14)

    A method for manufacturing a display device, the display device comprising: a first display element; a second display element; a first insulating layer; and a conductive layer, the first display element includes: a first pixel electrode having a function of reflecting visible light; and a liquid crystal And a first common electrode having a function of transmitting visible light, the second display element includes: a second pixel electrode having a function of transmitting visible light; a light emitting layer; and a second common electrode having a function of reflecting visible light, the above method The method includes the steps of: forming the first common electrode on the first substrate; and forming a first region including a thickness of 0.1 μm or more and 3 μm or less on the manufacturing substrate using a thermosetting material, and the thickness is thinner than the first region. A step of forming a resin layer on the second region of the second layer; a step of forming the first pixel electrode on the resin layer; a step of forming the conductive layer so as to cover the second region simultaneously with the step of forming the first pixel electrode; A step of forming the first insulating layer on the first pixel electrode; sequentially forming the second pixel electrode on the insulating layer, A step of forming the second display element by the light emitting layer and the second common electrode; a step of bonding the manufacturing substrate to the second substrate using an adhesive; a step of irradiating a laser to the resin layer; A step of separating from the first pixel electrode; and disposing the liquid crystal between the first common electrode and the first pixel electrode, and bonding the first substrate and the second substrate using an adhesive to form the first Display element.         The method for manufacturing a display device according to item 1 of the scope of patent application, wherein in the step of separating the manufacturing substrate from the first pixel electrode, separating the resin layer from the interface of the manufacturing substrate, and further including the separation A step of exposing the conductive layer after the step.         The method for manufacturing a display device according to item 1 of the scope of patent application, wherein in the step of separating the manufacturing substrate from the first pixel electrode, within the resin layer and between the manufacturing substrate and the pixel electrode and the conductive layer Separation is performed at intervals, and a step of exposing the conductive layer after the separation step is also included.         The method for manufacturing a display device according to any one of claims 1 to 3, further comprising: a step of forming an insulating layer on the resin layer after forming the second region in the resin layer.         The method for manufacturing a display device according to item 1 of the scope of patent application, further comprising the step of forming an insulating layer on the resin layer after forming the second region in the resin layer to separate the manufacturing substrate from the first pixel electrode. In the step of separating the inside of the resin layer and the interface between the resin layer and the insulating layer, a step of exposing the conductive layer after the separating step is further included.         The method for manufacturing a display device according to claim 4 or 5, wherein a material of the insulating layer is an inorganic insulating material.         The method for manufacturing a display device according to item 1 of the scope of patent application, wherein in the step of separating the manufacturing substrate from the first pixel electrode, the inside of the resin layer and the interface between the resin layer and the conductive layer are separated. .         The method for manufacturing a display device according to any one of claims 2 to 7, further comprising a step of connecting a wiring of an input signal or power to the exposed conductive layer through a connection layer.         The method for manufacturing a display device according to any one of claims 2 to 7, wherein the exposed conductive layer is connected to the first common electrode through a connector.         The method for manufacturing a display device according to any one of claims 1 to 9, wherein the resin layer is formed using a solution having a viscosity of 5 cP or more and less than 100 cP.         The method for manufacturing a display device according to any one of claims 1 to 10, wherein the resin layer is formed using a solution having a viscosity of 10 cP or more and less than 50 cP.         The method for manufacturing a display device according to any one of claims 1 to 11, wherein the resin layer is formed using a spin coater.         The method for manufacturing a display device according to any one of claims 1 to 12, further comprising: forming a layer including a channel in a region between the step of forming the first pixel electrode and the step of forming the second pixel electrode. A step of forming a transistor of an oxide semiconductor in which the resin layer is heated at a temperature higher than a heating temperature in the step of forming the transistor.         The method for manufacturing a display device according to any one of claims 1 to 13, wherein a material forming the resin layer is a material having photosensitivity.