JP4754876B2 - Display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a display device, and more particularly to a display device with improved viewing angle characteristics in a self-luminous display device.

  A light-emitting device using light emission from an electroluminescence element (light-emitting element) is a device that has attracted attention as a display device with a high viewing angle and low power consumption.

  There are an active matrix type and a passive matrix type as a driving method of a light-emitting device mainly used for display. An active matrix light-emitting device with a driving method can control light emission and non-light emission for each light-emitting element. Therefore, it can be driven with lower power consumption than a passive matrix light-emitting device, and is suitable not only as a display portion of a small electrical appliance such as a mobile phone but also as a display portion of a large-sized television receiver or the like. .

  In the active matrix light-emitting device, a circuit for controlling driving of each light-emitting element is provided for each light-emitting element. The circuit and the light-emitting element are arranged on the substrate so that extraction of emitted light to the outside is not hindered by the circuit. In addition, a light-transmitting insulating film is stacked in a portion overlapping with the light-emitting element, and light emission is emitted outside through the insulating film. These insulating films are provided to form circuit elements such as transistors and capacitors, which are components of the circuit, or wiring.

  By the way, when light emission passes through the stacked insulating films, the light reflected at the interface may cause multiple interference due to the difference in the refractive index of each insulating film. As a result, there arises a problem that the emission spectrum changes depending on the angle at which the emission extraction surface is viewed, and the viewing angle characteristics are deteriorated.

For example, Patent Document 1 raises a problem that visibility and viewing angle characteristics deteriorate due to a difference in refractive index of each layer that passes when light emitted from the light emitting element is emitted to the outside. A light-emitting device in which such a problem does not easily occur is proposed.
JP 2003-133062 A

Further, Patent Document 2 raises a problem that viewing angle characteristics are deteriorated in a light emitting element having a resonance structure constituted by electrodes and light emitting layers of the light emitting element, and a resonance structure of the light emitting element is provided so as to solve the problem. A devised display element is proposed.
JP 2002-367770 A

  However, since the refractive index is a value inherent to the substance, it is very difficult to select a material that satisfies both the performance and refractive index required for each layer, such as insulation and passivation performance, in the configuration of Patent Document 1. It is.

  Further, in the case of the configuration as in Patent Document 2, since attention is paid only to a light emitting element composed of an opposing electrode and an organic layer sandwiched between the electrodes, there are many in addition to the light emitting element as in the active matrix type. In a light-emitting device in which light is emitted outside the light-emitting device through this layer, there is a possibility that deterioration in viewing angle characteristics cannot be sufficiently suppressed.

  Therefore, an object of the present invention is to provide a display device that can easily improve viewing angle characteristics in an active matrix display device.

  In the display device of the present invention for solving the above problems, a thin film transistor and a light emitting element are formed over a substrate. In addition, a plurality of layers are optically formed between the substrate and the light emitting element, and a layer having a refractive index of n1 and a layer having a refractive index of n2 are sequentially stacked on the plurality of layers. N3, n2, and n3 have a relationship of n1 <n2> n3 or n1> n2 <n3, and the center wavelength of light emission from the light emitting element is Assuming λ, the optical thickness of the layer having the refractive index of n2 is approximately an integral multiple of λ / 2.

  In the display device of the present invention for solving the above problems, a first base insulating film formed on a light-transmitting substrate, and a second base insulating film formed thereon, A thin film transistor having a semiconductor layer, a gate insulating film, and a gate electrode is formed. Then, a first insulating film formed over the thin film transistor, a second insulating film formed over the first insulating film, and a second insulating film are formed on the semiconductor layer, and contact holes are formed in the semiconductor layer. And a light-emitting element electrically connected to the wiring. In addition, the substrate-side electrode of the light-emitting element has a light-transmitting property, and the first base insulating film is formed of a material having a refractive index larger or smaller than the refractive index of the other film in contact with the substrate, The first insulating film is formed of a material having a refractive index larger or smaller than the refractive index of other films in contact with the upper and lower sides. When the center wavelength of light emitted from the light emitting element is λ, the optical thickness of the first base insulating film and the optical thickness of the first insulating film are each approximately an integral multiple of λ / 2.

  In the display device of the present invention for solving the above problems, a first base insulating film formed on a light-transmitting substrate, and a second base insulating film formed thereon, A thin film transistor having a semiconductor layer, a gate insulating film, and a gate electrode is formed. Then, a first insulating film formed over the thin film transistor, a second insulating film formed over the first insulating film, and a second insulating film are formed on the semiconductor layer, and contact holes are formed in the semiconductor layer. And a light-emitting element electrically connected to the wiring. In addition, the substrate-side electrode of the light-emitting element has a light-transmitting property, and the first base insulating film is formed of a material having a refractive index larger or smaller than the refractive index of the other film in contact with the substrate, The first insulating film is formed of a material having a refractive index larger or smaller than the refractive index of other films in contact with the upper and lower sides. The center wavelength of light emitted from the light emitting element is λ, the total optical thickness of the second base insulating film and the gate insulating film is L1, and each of the first base insulating film and the first insulating film is When the optical thickness is L2, and m is an integer of 1 or more, L1 = −L2 + (2m−1) λ / 4 is approximately satisfied.

  In the display device of the present invention for solving the above problems, a first base insulating film formed on a light-transmitting substrate, and a second base insulating film formed thereon, A thin film transistor having a semiconductor layer, a gate insulating film, and a gate electrode is formed. Then, a first insulating film formed over the thin film transistor, a second insulating film formed over the first insulating film, and a second insulating film are formed on the semiconductor layer, and contact holes are formed in the semiconductor layer. And a light-emitting element electrically connected to the wiring. In addition, the substrate-side electrode of the light-emitting element has a light-transmitting property, and the first base insulating film and the first insulating film are formed using a material mainly containing silicon nitride, and the second base insulating film The gate insulating film is formed of a material mainly composed of silicon oxide. The thickness of the first base insulating film is 120 nm to 162 nm, the thickness of the first insulating film is 120 nm to 162 nm, and the total value of the gate insulating film and the second base insulating film is in the range of 132 nm to 198 nm. .

  In the display device of the present invention for solving the above problems, a first base insulating film formed on a light-transmitting substrate, and a second base insulating film formed thereon, A thin film transistor having a semiconductor layer, a gate insulating film, and a gate electrode is formed. In addition, the semiconductor device includes an insulating film formed so as to cover the thin film transistor, a wiring formed on the insulating film and connected to the semiconductor layer through a contact hole, and a light-emitting element electrically connected to the wiring. Further, the substrate-side electrode of the light-emitting element has a light-transmitting property, and the first base insulating film is formed of a material having a refractive index larger or smaller than that of the other film in contact with the substrate and the substrate. . When the center wavelength of light emitted from the light emitting element is λ, the optical thickness of the first base insulating film is approximately an integral multiple of λ / 2.

  In the display device of the present invention for solving the above problems, a thin film transistor having a semiconductor layer, a gate insulating film, and a gate electrode is formed on a base insulating film formed on a substrate. Then, a first insulating film formed so as to cover the thin film transistor, a second insulating film formed so as to cover the first insulating film, and a contact hole formed in the semiconductor layer is formed on the second insulating film. And a light-emitting element electrically connected to the wiring. Further, the substrate-side electrode of the light-emitting element has a light-transmitting property, and the base insulating film is formed of a material having a refractive index larger or smaller than that of the other film in contact with the substrate and the first insulating film. Is made of a material having a refractive index larger or smaller than that of the other films in contact with each other. When the center wavelength of light emitted from the light emitting element is λ, the optical thickness of the base insulating film and the optical thickness of the first insulating film are each approximately an integral multiple of λ / 2.

  In the display device of the present invention for solving the above problems, a thin film transistor having a semiconductor layer, a gate insulating film, and a gate electrode is formed on a base insulating film formed on a substrate. In addition, the semiconductor device includes an insulating film formed so as to cover the thin film transistor, a wiring formed over the insulating film and connected to the semiconductor layer through a contact hole, and a light-emitting element electrically connected to the wiring. In addition, the substrate-side electrode of the light-emitting element has a light-transmitting property, and the base insulating film is formed using a material having a refractive index larger or smaller than that of the other film in contact with the substrate and the substrate. Further, assuming that the center wavelength of light emitted from the light emitting element is λ, the optical thickness of the base insulating film is approximately an integral multiple of λ / 2.

  In the display device of the present invention for solving the above problems, a thin film transistor having a semiconductor layer, a gate insulating film, and a gate electrode is formed on a base insulating film formed on a substrate. A first insulating film formed so as to cover the thin film transistor; a second insulating film formed so as to cover the thin film transistor; and a wiring formed thereon and connected to the semiconductor layer via a contact hole; And a light emitting element which is electrically connected to the wiring. The substrate-side electrode of the light-emitting element has a light-transmitting property, and the first insulating film is formed of a material having a refractive index that is larger or smaller than the refractive index of other films that are in contact with the top and bottom. When the center wavelength of light emitted from the light emitting element is λ, the optical thickness of the first insulating film is approximately an integral multiple of λ / 2.

  In the display device of the present invention for solving the above-described problems, a thin film transistor having a first base insulating film and a second base insulating film formed on a substrate and having a semiconductor layer, a gate insulating film, and a gate electrode is provided. Is formed. A first insulating film formed over the thin film transistor; a second insulating film formed over the first insulating film; and a contact hole formed in the second insulating film on the semiconductor layer. And a light-emitting element electrically connected to the wiring. The substrate-side electrode of the light-emitting element has a light-transmitting property, and the second base insulating film, the gate insulating film, and the first insulating film are optically one layer, and the second The refractive index of the optically single layer formed of the base insulating film, the gate insulating film, and the first insulating film is greater than the refractive indexes of the first base insulating film and the second insulating film, or The optical thickness of an optically single layer composed of the second base insulating film, the gate insulating film, and the first insulating film is small when the central wavelength of light emission from the light emitting element is λ. It is approximately an integral multiple of λ / 2.

  In the display device of the present invention for solving the above-described problems, a thin film transistor having a first base insulating film and a second base insulating film formed on a substrate and having a semiconductor layer, a gate insulating film, and a gate electrode is provided. Is formed. Then, a first insulating film formed so as to cover the thin film transistor, a second insulating film formed so as to cover the first insulating film, and a contact hole formed in the semiconductor layer is formed on the second insulating film. And a light-emitting element electrically connected to the wiring. Further, the substrate-side electrode of the light-emitting element has a light-transmitting property, and the first base insulating film and the second insulating film are formed of a material containing silicon nitride as a main component. The insulating film, the gate insulating film, and the first insulating film are formed of a material mainly composed of silicon oxide. The physical thickness of the first base insulating film is 120 nm to 162 nm, and the physical thickness of the second insulating film. The total thickness of the second base insulating film, the gate insulating film, and the first insulating film is in the range of 132 nm to 198 nm.

  The display device of the present invention is a display device having a simple configuration and improved viewing angle characteristics. In addition, since the display device of the present invention has improved viewing angle characteristics, it can provide a good display. Furthermore, the display device of the present invention can be manufactured without using a new process or a new material, and a display device with improved viewing angle characteristics can be easily obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention is not construed as being limited to the description of this embodiment mode.

  In a display device that emits light toward a substrate on which an active matrix type thin film transistor is formed, the present inventors reflect light from the light emitting element due to a film used for forming the thin film transistor. Focusing on the fact that multiple interference occurs, we have found that the influence on multiple interference can be greatly reduced by setting the film thickness causing the reflection to a specific film thickness.

  In the present invention, even if two or more films in contact with each other are manufactured by different processes, the materials constituting the plurality of films are the same material, a material having the same refractive index, or similar refraction. If the material has a ratio, it is optically regarded as one layer. The physical thickness is the actual thickness of the film of interest, and the optical thickness is assumed to pass light of a certain wavelength through the film, and the physical thickness is the wavelength of the light. The product multiplied by the refractive index of the film. The center wavelength is the wavelength having the highest intensity among the light emitted from the light emitting element of interest. Or it is good also as a wavelength which an implementer will obtain from the said light emitting element.

  When light passes through a plurality of layers, reflection becomes a problem when the light passes through an interface where layers having different refractive indexes are laminated. Such a laminated structure is often seen when a thin film transistor is manufactured. For example, a laminate of a silicon oxide film and a silicon nitride film is a typical example. If there is a difference in refractive index between the silicon oxide film and the silicon nitride film, the problem of multiple interference due to light reflection is large.

  In addition, in a semiconductor device, materials used are limited due to insulation, film quality, blocking performance, compatibility with a semiconductor layer, and the like, and it is necessarily a repetitive laminated structure of about two types of materials. Many. In addition, materials used in other cases often have a refractive index similar to that of either one.

  In the present invention, when light emitted from the light emitting element passes through one layer having a large or small refractive index n before exiting to the outside, that is, n1 <n2> n3 or n1> from the incident direction of light. When passing through a laminated structure having a refractive index relationship of n2 <n3, the optical thickness L of the layer (the layer having the refractive index n2) is λm / 2 (m is an integer of 1 or more). . In terms of the physical thickness d, this is λm / 2n where n is the refractive index of the film constituting the layer and λ is the center wavelength of the light emitted from the light emitting element.

  By adopting this configuration, the reflection that occurs when light is incident on the layer (the layer having the refractive index n2) and the reflection that occurs when light is emitted from the layer cancel each other. The reflection caused by the presence of the layer is reduced. By reducing this reflection, it becomes possible to obtain a display device in which the occurrence of standing waves is suppressed and the viewing angle dependency is improved. In order to obtain a display device having good viewing angle dependency, the reflectance of the layer should be 1% or less, and the optical thickness L of the layer giving such reflectance is λ / 2. It is about ± 6%. From this point of view, the outline in the present invention and the present specification has a margin of ± 6%.

  In the present invention, when light emitted from the light emitting element passes through two layers having a large or small refractive index before the light is emitted to the outside, that is, n1 <n2> n3 <n4 from the incident direction of light. When passing through a laminated structure having a refractive index relationship of> n5 or n1> n2 <n3> n4 <n5, the optical thickness L of the two layers (the layers having the refractive indexes of n2 and n4). Is λm / 2 (m is an integer of 1 or more). In terms of the physical thickness d, this is λm / 2n where n is the refractive index of the layer and λ is the center wavelength of light emitted from the light emitting element.

  Note that the two layers (the layers having the refractive indexes of n2 and n4) are preferably formed of the same material, the same refractive index, or the same refractive index. By adopting this configuration, the reflection that occurs when light enters the layer and the reflection that occurs when light exits from the layer cancel each other, and as a result, the reflectance of the layer decreases. By reducing the reflectance, it is possible to obtain a display device in which the occurrence of standing waves is suppressed and the viewing angle dependency is improved. In order to obtain a display device having good viewing angle dependency, the reflectance of the layer should be 1% or less, and the optical thickness L of the film is about ± 6% of λ / 2. It is.

  In the present invention, when light emitted from the light emitting element passes through two layers having a large or small refractive index before the light is emitted to the outside, that is, n1 <n2> n3 <n4 from the incident direction of light. When passing through one laminated structure having a refractive index relationship of> n5 or n1> n2 <n3> n4 <n5, the optical thickness of the two layers (the layers having the refractive indexes of n2 and n4) is set. When the optical thickness of a layer sandwiched between the two layers (the layer having the refractive index n3) is L2, L2 = −L1 + (2m−1) where λ is the center wavelength of light emitted from the light emitting element. ) Satisfy λ / 4.

  The material constituting the two layers (the layer having the refractive index of n2 and n4) is preferably the same material, the material having the same refractive index, or the material having the same refractive index. The layers sandwiched (the layer having the refractive index n3) are optically one layer. By adopting this configuration, the reflection occurring at the interface between the layer having the refractive index n1 and the layer having the refractive index n2 is offset by the reflection occurring at the interface between the layer having the refractive index n3 and the layer having the refractive index n4. In addition, the reflection occurring at the interface between the layer having the refractive index n2 and the layer having the refractive index n3 is offset by the reflection occurring at the interface between the layer having the refractive index n4 and the layer having the refractive index n5. The reflectance of the laminated film is reduced. By reducing the reflectance, it is possible to obtain a display device in which the occurrence of standing waves is suppressed and the viewing angle dependency is improved. In order to obtain a display device having good viewing angle dependency, the reflectivity of the film may be 1% or less, and the physical thickness d of the film that gives such reflectivity is L1 or L2. Each is about ± 6%.

  In addition, in the present invention, a layer in which two layers having a refractive index of about 1.8 and one layer having a refractive index of about 1.5 are sandwiched between light emitted from the light emitting element until the light is emitted to the outside. When passing through the structure, the physical thickness of the layer having a refractive index of about 1.8 is set to 120 nm to 162 nm, and the physical thickness of the film having a refractive index of about 1.5 is set to 132 nm to 198 nm. By adopting this configuration, it is possible to obtain a display device in which the reflectance of the film is reduced, the generation of standing waves is suppressed, and the viewing angle dependency is improved. In order to obtain a display device having good viewing angle dependency, the reflectance of the layer should be 1% or less, and the above-described physical thickness is a film thickness that gives such reflectance.

(Embodiment 1)
In this embodiment mode, an example of a display device of the present invention will be described with reference to FIG.

  In the display device of this embodiment, a first base insulating film 101 and a second base insulating film 102 are formed in this order from the substrate 100 side over a light-transmitting substrate 100. A semiconductor layer 103 is formed over the second base insulating film 102, and a gate insulating film 104 is formed to cover the semiconductor layer 103 and the second base insulating film 102. A gate electrode 105 is formed over the gate insulating film 104 so as to partially overlap the semiconductor layer 103. The gate electrode 105 and the gate insulating film 104 are covered with a first insulating film 106, and the first insulating film 106 is further covered with a second insulating film 107. The second insulating film 107 is electrically connected to the semiconductor layer 103 through a contact hole provided through the second insulating film 107, the first insulating film 106, and the gate insulating film 104. Electrodes 108 and 109 are provided. A thin film transistor 110 in the pixel portion is formed from the semiconductor layer 103, the gate insulating film 104, the gate electrode 105, and the electrodes 108 and 109.

  In addition, the first electrode 111 of the light-emitting element is formed so as to partially overlap with one electrode 109 of the thin film transistor 110. Further, a third insulating film called a partition 112 or the like that covers the second insulating film 107 and at least the end portion of the first electrode 111 and has an opening through which the first electrode 111 is exposed is formed on the upper portion. ing. A light emitting stack 113 is formed covering at least the opening, a second electrode 114 of the light emitting element is formed covering the partition 112 and the light emitting stack 113, and the first electrode 111, the light emitting stack 113, and A light emitting element 115 including the second electrode 114 is configured.

  As a material for the substrate 100, light-transmitting glass, quartz, plastic (polyimide, acrylic, polyethylene terephthalate, polycarbonate, polyacrylate, polyethersulfone, or the like) can be used. These substrates may be used after being polished by CMP or the like, if necessary. In this embodiment, a glass substrate is used.

  The first base insulating film 101 and the second base insulating film 102 prevent an element such as an alkali metal or an alkaline earth metal in the substrate 100 that adversely affects the characteristics of the semiconductor film from diffusing into the semiconductor layer. Provided for this purpose. As a material, silicon oxide, silicon nitride, silicon oxide containing nitrogen, silicon nitride containing oxygen, or the like can be used. By the way, it is known that a film having silicon nitride as a main component has a large blocking effect of impurity elements (ions). On the other hand, a film mainly composed of silicon oxide has advantages in that it has a wider band gap, better insulation, and a lower trap order than a film mainly composed of silicon nitride. In this embodiment mode, the first base insulating film 101 is formed using a film containing silicon nitride as a main component, and the second base insulating film 102 is formed using a film containing silicon oxide as a main component. And good thin film transistor performance can be obtained at the same time.

  In this embodiment mode, the physical thickness d of the first base insulating film 101 is such that the center wavelength of light emitted from the light emitting element 115 is λ, and the refractive index of the first base insulating film 101 at the center wavelength is n. Then, λm / 2n (m is an integer of 0 or more).

  The display device of the present invention is an active matrix display device having a plurality of thin film transistors on a second base insulating film in a pixel portion, and the thin film transistor 110 in FIG. 1 shows one of them. ing. Note that a thin film transistor may be formed in a portion other than the pixel portion in the display device, and a driver circuit, a signal processing circuit, an audio circuit, a CPU, and the like may be formed.

  The thin film transistor 110 may be formed by a known method, regardless of the type, but the first insulating film 106 is formed of a film containing silicon nitride as a main component and is a passivation that prevents impurities from entering the semiconductor layer 103. The film can be used as a hydrogenation film that terminates dangling bonds of the semiconductor layer 103 with hydrogen contained in the film.

  In this embodiment mode, the physical thickness d of the first insulating film 106 is set to λm /, where λ is the center wavelength of light emitted from the light emitting element 115 and n is the refractive index of the first insulating film 106 at the center wavelength. 2n (m is an integer of 0 or more).

  In this embodiment, the gate insulating film 104 is formed using the same material as the second base insulating film 102, a material having the same refractive index, or a material having substantially the same refractive index. In this embodiment, since the second base insulating film 102 is formed using a film containing silicon oxide as a main component, the gate insulating film 104 is also formed using a film containing silicon oxide as a main component, and optically It can be regarded as one layer.

  The second insulating film 107 is formed of a coating film having self-flatness that can reduce unevenness in the lower layer in order to improve the aperture ratio of the light emitting element 115. As such an insulating film, a skeleton structure is formed by a bond of acrylic, polyimide, silicon, and oxygen, and an organic group (for example, an alkyl group or an aryl group) containing at least hydrogen as a substituent, a fluoro group, or at least hydrogen. There are materials having an organic group and a fluoro group, so-called siloxane. In this embodiment, a film formed of siloxane is used as the second insulating film 107.

  In the light-emitting element 115, a light-emitting stacked body 113 is sandwiched between a first electrode 111 and a second electrode 114. Further, one of the first electrode 111 and the second electrode 114 functions as an anode and the other functions as a cathode. The light-emitting element is separated from other light-emitting elements by a partition wall 112 called a bank, and the partition wall 112 is formed so as to cover at least the end portion of the first electrode 111, and the end portion of the partition wall 112 itself on the light-emitting element side is It is desirable to have a taper shape that has a curvature and the curvature changes continuously.

  The partition 112 may be formed of either an organic material or an inorganic material, such as a photosensitive or non-photosensitive acrylic, polyimide, siloxane or silicon oxide film, a silicon nitride film as a main component, or the like. These materials can be used.

  The first electrode 111 is preferably made of a light-transmitting conductive material such as indium tin oxide (ITO). In addition to ITO, ITO containing silicon oxide, IZO (Indium Zinc Oxide) containing 2 to 20% zinc oxide in indium oxide or zinc oxide itself, GZO (Galium Zinc Oxide) containing gallium in zinc oxide. ) Etc. may be used.

  In addition, the light-emitting stacked body 113 includes a light-emitting substance and has a single layer or multiple layers. Note that the light emitting laminate 113 may be made of either an organic material or an inorganic material, or may include both an inorganic material and an organic material.

  In the display device in this embodiment having such a structure, the second insulating film 107, the first insulating film 106, and the gate insulating film 104 are emitted before light emitted from the light-emitting element 115 is emitted to the outside of the display device. , Passes through the second base insulating film 102, the first base insulating film 101, and the substrate 100. Among these, the first insulating film 106 and the first base insulating film 101 have a large difference in refractive index between the film sandwiching the film. Therefore, in this embodiment, the physical thickness d of the first insulating film 106 and the first base insulating film 101 is set to λm / 2n (m is an integer of 0 or more), that is, the first insulating film 106 and the first insulating film 106 By setting the optical thickness L of the base insulating film 101 to λm / 2 (m is an integer of 0 or more), the reflected light at the entrance side interface of the film is reflected by the reflected light at the exit side interface of the film. It becomes possible to attenuate, and the reflected light generated by the presence of the film can be significantly reduced. By reducing the reflected light, it is possible to suppress the occurrence of a standing wave caused by the interference between the incident light and the reflected light, and to suppress the deterioration of the viewing angle characteristics caused by the standing wave. . In addition, a display device with improved viewing angle characteristics can be manufactured.

  12 and 13, as in the structure of this embodiment mode, the first base insulating film 101 is a silicon nitride film containing oxygen on the substrate 100, and the second base insulating film 102 and the gate insulating film 104 are nitrogen. In the case where the first insulating film 106 is formed of a silicon nitride film containing oxygen, the second insulating film 107 is formed of siloxane, and the light emitting element 115 is sequentially formed thereon. When the thickness obtained by adding the gate insulating film 104 and the second base insulating film 102, the thickness of the first insulating film 106, and the thickness of the first base insulating film 101 are changed, Reflectance between the insulating film 107 and the first insulating film 106 (this is reflected light between the first insulating film 106 and the gate insulating film 104, the second base insulating film 102 and the first base insulating film) Reflected light between the film 101 and the first base insulating film 101 and the substrate 100 Of the reflected light is also the reflectance in conjunction) that is the result of simulation using the methods of how varying the or Fresnel coefficients. Note that in this embodiment, the gate insulating film 104 and the second base insulating film 102 are layers formed using the same material; therefore, the gate insulating film 104 can be regarded as an optically single layer. In addition, the thickness of the second base insulating film 102 is discussed based on the total film thickness.

  In these graphs, the horizontal axis represents the physical thickness of a film made of silicon nitride containing oxygen (the thickness of each of the first base insulating film 101 and the first insulating film 106), and the vertical axis represents 2 above. The physical thickness of the film made of silicon oxide containing nitrogen existing between the films (the sum of the film thicknesses of the second base insulating film 102 and the gate insulating film 104) is expressed as the first insulating film. The reflectance distribution at 106 is shown. FIG. 12 shows the change in reflectance for a single color, and FIG. 13 shows the average reflectance at wavelengths from 400 nm to 700 nm.

  FIG. 12A shows a simulation result with respect to light having a center wavelength λ = 450 nm corresponding to blue light emission. The physical thickness d of the first insulating film 106 and the first base insulating film 101 is optical. It can be seen that the reflectance is low in the vicinity of 125 nm corresponding to the target thickness L = λ / 2. If the reflection between the first insulating film 106 and the second insulating film 107 is 1% or less, it is considered that the viewing angle characteristic is hardly adversely affected. The range showing such reflectance is shown in FIG. Further, the physical thickness d centered around 125 nm was in the range of 115 nm to 133 nm. In this film thickness range, a structure having a reflectance of 1% or less can be provided regardless of the total film thickness of the gate insulating film 104 and the second base insulating film 102, and a display device with favorable viewing angle characteristics is provided. be able to.

  FIG. 12B shows a simulation result with respect to light having a center wavelength λ = 540 nm corresponding to green light emission. The physical thickness d of the first insulating film 106 and the first base insulating film 101 is optical. It can be seen that the reflectance is low in the vicinity of 152 nm corresponding to the target thickness L = λ / 2. If the reflection at the interface between the first insulating film 106 and the second insulating film 107 is 1% or less, it is considered that the viewing angle characteristic is hardly adversely affected. The physical thickness d was in the range of 138 nm to 162 nm. In this film thickness range, a structure having a reflectance of 1% or less can be provided regardless of the total film thickness of the gate insulating film 104 and the second base insulating film 102, and a display device with favorable viewing angle characteristics is provided. be able to.

  FIG. 12C shows a simulation result with respect to light having a center wavelength λ = 620 nm corresponding to red light emission. The physical thickness d of the first insulating film 106 and the first base insulating film 101 is optical. It can be seen that the reflectance is low in the vicinity of 175 nm corresponding to the target thickness L = λ / 2. If the reflection at the interface between the first insulating film 106 and the second insulating film 107 is 1% or less, it is considered that the viewing angle characteristic is hardly adversely affected. The physical thickness d was in the range of 160 nm to 186 nm. In this film thickness range, a structure having a reflectance of 1% or less can be provided regardless of the total film thickness of the gate insulating film 104 and the second base insulating film 102, and a display device with favorable viewing angle characteristics is provided. be able to.

  Thus, when the center wavelength is clear, that is, the display device to be manufactured is a single color display or a multicolor display using a color filter, and the maximum wavelength of light emitted from the light emitting element is a single or other than the center wavelength. When the intensity of the maximum wavelength is sufficiently small, the physical thickness d of the first insulating film 106 and the first base insulating film 101 is set to a film thickness corresponding to the approximate optical thickness L = λ / 2. Thus, it can be seen that reflection at the interface between the first insulating film 106 and the second insulating film 107 can be kept low. In this case, the sum of the thicknesses of the gate insulating film 104 and the second base insulating film 102 may be any film thickness.

  Further, from these simulation data, the optical thicknesses of the first insulating film 106 and the first base insulating film 101 are small enough to allow the reflectance in the film thickness range of ± 6% of λ / 2. It can be seen that a display device having good viewing angle characteristics can be obtained. Therefore, in the present specification, when both the physical thickness d and the optical thickness L are approximate, a margin of ± 6% is assumed.

  12A to 12C, L2 (the sum of the optical thicknesses of the gate insulating film 104 and the second base insulating film 102), L1 (the first insulating film 106 and the first base insulating film). Even when the optical thickness of each of the films 101 satisfies L2 = −L1 + (2m−1) λ / 4 (where m is an integer of 1 or more), the reflectance is small, and the viewing angle dependency is low. It is expected to improve. In this case, it is necessary to set both the film thicknesses of L2 and L1, and the reflection that occurs between the second insulating film 107 and the first insulating film 106 is different from that of the second base insulating film 102 and the first insulating film 106. The reflection occurring between the first base insulating film 101 and the substrate 100 is offset by the reflection occurring between the first base insulating film 101 and the first insulating film 106 and the gate insulating film 104. It is considered that the reflection is reduced by canceling out the reflection.

  In this case as well, the reflectance is so low that the viewing angle dependency is acceptable in the range of about ± 6% with respect to L2 and L1 calculated in this case. By doing so, it is possible to provide a display device that can perform good display with reduced viewing angle dependency.

  FIG. 13 is an average of reflectances at 400 nm to 700 nm, and the film thickness range that satisfies the reflectance of 1% or less is the physical thickness d of the first insulating film 106 and the first base insulating film 101. Is in the range of 120 nm to 162 nm, and the physical thickness d obtained by adding the gate insulating film 104 and the second base insulating film 102 is in the range of 132 nm to 198 nm. By setting these physical thicknesses within the above range, a display device having a plurality of types of light-emitting elements having different center wavelengths, such as a full-color display device with different colors and a display device using a white light-emitting element. Even if there is only one kind of light emitting element, it is possible to obtain a good viewing angle characteristic even in a display device having a plurality of maximum wavelengths with high intensity in the spectrum of light emitted from the light emitting element.

  Even when the center wavelength is clear, the physical thickness d of the first insulating film 106 and the first base insulating film 101 is 120 nm to 162 nm, and the gate insulating film 104 and the second base base When the physical thickness d obtained by adding the insulating films 102 is in the range of 132 nm to 198 nm, a display device with good viewing angle characteristics can be manufactured at any wavelength.

  Note that the film thickness of each film is set so that the film thickness at the stage when the semiconductor device is completed becomes such a film thickness. In the case of actually manufacturing a semiconductor device, the film located under the film is reduced by etching for forming the semiconductor layer 103, the gate electrode 104, the electrodes 108 and 109, the first electrode 111 of the light emitting element, and the like. In some cases. In this case, in consideration of the film thickness reduction, it is necessary to adjust so that the film thickness reaches a specified thickness in a portion where the light from the light emitting element 115 hits the optical path when it is emitted to the outside of the display device. Can be done as appropriate. That is, according to the present invention, it is only necessary that the thickness of each layer in the portion corresponding to the optical path when light from the light emitting element 115 is emitted to the outside of the display device is as described above.

(Embodiment 2)
In this embodiment, another structure of the present invention will be described with reference to FIG. The display device in this embodiment is almost the same as the structure in Embodiment 1, but the first insulating film 106 in Embodiment 1 is not formed. In this case, the first base insulating film 101 and the first layer are the only films having different refractive indexes that pass before the light emitted from the light emitting element 115 is emitted to the outside.

  For this reason, the optical thickness L of the first base insulating film 101 is approximately an integral multiple of λ / 2, where λ is the center wavelength of the light emitted from the light emitting element 115, and reflection at the incident side interface of the film is performed. Light can be attenuated by reflected light at the output side interface of the film, and reflected light generated by the presence of the film can be significantly reduced. By reducing the reflected light, it is possible to suppress the occurrence of a standing wave caused by the interference between the incident light and the reflected light, and to suppress the deterioration of the viewing angle characteristics caused by the standing wave. . In addition, a display device with improved viewing angle characteristics can be manufactured.

  Note that in this embodiment mode, it is important that the second base insulating film 102, the gate insulating film 104, and the second insulating film 107 are formed of materials having substantially the same refractive index.

  Since other configurations are the same as those in the first embodiment, refer to the description in the first embodiment.

  Note that the film thickness of each film is set so that the film thickness at the stage when the semiconductor device is completed becomes such a film thickness. In the case of actually manufacturing a semiconductor device, the film located under the film is reduced by etching for forming the semiconductor layer 103, the gate electrode 104, the electrodes 108 and 109, the first electrode 111 of the light emitting element, and the like. In some cases. In this case, in consideration of the film thickness reduction, it is necessary to adjust so that the film thickness reaches a specified thickness in a portion where the light from the light emitting element 115 hits the optical path when it is emitted to the outside of the display device. Can be done as appropriate. That is, according to the present invention, it is only necessary that the thickness of each layer in the portion corresponding to the optical path when light from the light emitting element 115 is emitted to the outside of the display device is as described above.

(Embodiment 3)
In this embodiment, another structure of the present invention will be described with reference to FIG. The display device in this embodiment is almost the same as the structure in Embodiment 1. However, the second base insulating film 102 in Embodiment 1 is not formed, and the base insulating film is only the base insulating film 116. It has become. In this embodiment, an example in which the base insulating film 116 is formed using silicon nitride containing oxygen is described. In this case, the films having different refractive indexes that pass until the light emitted from the light emitting element 115 is emitted to the outside are two layers of the first insulating film 106 and the base insulating film 116.

  Here, the optical thickness L of the first insulating film 106 and the base insulating film 116 is approximately an integral multiple of λ / 2, where λ is the center wavelength of light emitted from the light emitting element 115, so The reflected light at the side interface can be attenuated by the reflected light at the output side interface of the film, and the reflected light generated by the presence of the film can be significantly reduced. By reducing the reflected light, it is possible to suppress the occurrence of a standing wave caused by the interference between the incident light and the reflected light, and to suppress the deterioration of the viewing angle characteristics caused by the standing wave. . In addition, a display device with improved viewing angle characteristics can be manufactured.

  Alternatively, L2 is an optical thickness of the first insulating film 106 and the base insulating film 116, and L2 is an optical thickness of the gate insulating film 104 between the first insulating film 106 and the base insulating film 116. = -L1 + (2m-1) .lamda. / 4. As a result, reflected light can be remarkably reduced, generation of standing waves caused by interference between incident light and reflected light can be suppressed, and deterioration of viewing angle characteristics caused by standing waves can be suppressed. It becomes possible. In addition, a display device with improved viewing angle characteristics can be manufactured.

  Alternatively, the physical thickness d of the first insulating film 106 and the base insulating film 116 is in the range of 120 nm to 162 nm, and the physical thickness d of the gate insulating film 104 is in the range of 132 nm to 198 nm. As a result, reflected light can be remarkably reduced, generation of standing waves caused by interference between incident light and reflected light can be suppressed, and deterioration of viewing angle characteristics caused by standing waves can be suppressed. It becomes possible. In addition, a display device with improved viewing angle characteristics can be manufactured.

  Since other configurations are the same as those in the first embodiment, refer to the description in the first embodiment.

  Note that the film thickness of each film is set so that the film thickness at the stage when the semiconductor device is completed becomes such a film thickness. In the case of actually manufacturing a semiconductor device, the film located under the film is reduced by etching for forming the semiconductor layer 103, the gate electrode 104, the electrodes 108 and 109, the first electrode 111 of the light emitting element, and the like. In some cases. In this case, in consideration of the film thickness reduction, it is necessary to adjust so that the film thickness reaches a specified thickness in a portion where the light from the light emitting element 115 hits the optical path when it is emitted to the outside of the display device. Can be done as appropriate. That is, according to the present invention, it is only necessary that the thickness of each layer in the portion corresponding to the optical path when light from the light emitting element 115 is emitted to the outside of the display device is as described above.

(Embodiment 4)
In the present embodiment, another structure of the present invention will be described with reference to FIG. The display device in this embodiment is almost the same as the structure in Embodiment 1, but the second base insulating film 102 and the first insulating film 106 in Embodiment 1 are not formed, and the base insulating film Is only the base insulating film 116. In this embodiment, an example in which the base insulating film 116 is formed using silicon nitride containing oxygen is described. In this case, a film having a different refractive index that passes through before the light emitted from the light emitting element 115 is emitted to the outside is one layer of the base insulating film 116.

  Here, the optical thickness L of the base insulating film 116 is approximately an integral multiple of λ / 2, where λ is the center wavelength of the light emitted from the light emitting element 115, so that the reflected light at the incident side interface of the film is reflected. Can be attenuated by the reflected light at the output side interface of the film, and the reflected light generated by the presence of the film can be significantly reduced. By reducing the reflected light, it is possible to suppress the occurrence of a standing wave caused by the interference between the incident light and the reflected light, and to suppress the deterioration of the viewing angle characteristics caused by the standing wave. . In addition, a display device with improved viewing angle characteristics can be manufactured.

  Note that in this embodiment mode, it is important to form the gate insulating film 104 and the second insulating film 107 with materials having substantially the same refractive index.

  Since other configurations are the same as those in the first embodiment, refer to the description in the first embodiment.

  Note that the film thickness of each film is set so that the film thickness at the stage when the semiconductor device is completed becomes such a film thickness. In the case of actually manufacturing a semiconductor device, the film located under the film is reduced by etching for forming the semiconductor layer 103, the gate electrode 104, the electrodes 108 and 109, the first electrode 111 of the light emitting element, and the like. In some cases. In this case, in consideration of the film thickness reduction, it is necessary to adjust so that the film thickness reaches a specified thickness in a portion where the light from the light emitting element 115 hits the optical path when it is emitted to the outside of the display device. Can be done as appropriate. That is, according to the present invention, it is only necessary that the thickness of each layer in the portion corresponding to the optical path when light from the light emitting element 115 is emitted to the outside of the display device is as described above.

(Embodiment 5)
In this embodiment, another structure of the present invention will be described with reference to FIG. The display device in this embodiment is almost the same as the structure in Embodiment 1, but the first base insulating film 101 in Embodiment 1 is not formed, and the base insulating film is only the base insulating film 117. It has become. In this embodiment, an example in which the base insulating film 117 is formed using silicon oxide containing nitrogen is described. In this case, the film having a different refractive index that passes through before the light emitted from the light emitting element 115 is emitted to the outside is one layer of the first insulating film 106.

  Here, the optical thickness L of the first insulating film 106 is approximately an integral multiple of λ / 2, where λ is the center wavelength of the light emitted from the light emitting element 115, so that reflection at the incident side interface of the film is performed. Light can be attenuated by reflected light at the output side interface of the film, and reflected light generated by the presence of the film can be significantly reduced. By reducing the reflected light, it is possible to suppress the occurrence of a standing wave caused by the interference between the incident light and the reflected light, and to suppress the deterioration of the viewing angle characteristics caused by the standing wave. . In addition, a display device with improved viewing angle characteristics can be manufactured.

  Since other configurations are the same as those in the first embodiment, refer to the description in the first embodiment.

  Note that the film thickness of each film is set so that the film thickness at the stage when the semiconductor device is completed becomes such a film thickness. In the case of actually manufacturing a semiconductor device, the film located under the film is reduced by etching for forming the semiconductor layer 103, the gate electrode 104, the electrodes 108 and 109, the first electrode 111 of the light emitting element, and the like. In some cases. In this case, in consideration of the film thickness reduction, it is necessary to adjust so that the film thickness reaches a specified thickness in a portion where the light from the light emitting element 115 hits the optical path when it is emitted to the outside of the display device. Can be done as appropriate. That is, according to the present invention, it is only necessary that the thickness of each layer in the portion corresponding to the optical path when light from the light emitting element 115 is emitted to the outside of the display device is as described above.

(Embodiment 6)
In this embodiment, another structure of the present invention will be described with reference to FIG. The display device in this embodiment is almost the same as the structure in Embodiment 1, but the fourth insulating film between the gate insulating film 104 and the gate electrode 105 and the first insulating film 106 in Embodiment 1 is used. 120 is formed. The fourth insulating film 120 is formed using the same material as the second base insulating film 102 and the gate insulating film 104, a material having the same refractive index, or a material having a similar refractive index. A stacked film including the insulating film 104 and the fourth insulating film 120 is optically formed as one layer. Furthermore, the physical thickness d of the optically laminated film composed of the second base insulating film 102, the gate insulating film 104, and the fourth insulating film 120 is set to a range of 132 nm to 198 nm, and the first insulating film is formed. The physical thickness d of the film 106 and the first base insulating film 101 is in the range of 120 nm to 162 nm.

  By the way, in the simulation result of FIG. 13 in Embodiment 1, the physical thickness d of the laminated film which is the optically one layer of the second base insulating film 102 and the gate insulating film 104 is in the range of 132 nm to 198 nm. The result is good. However, it has been found that there are preferable values for the thickness of the second base insulating film 102 and the gate insulating film 104 from the viewpoint of the operation of the thin film transistor 110. The values that can improve the viewing angle characteristics do not necessarily match. Therefore, in this embodiment mode, by forming the fourth insulating film 120, the second base insulating film 102 and the gate insulating film 104 have a thickness that is preferable for the operation of the thin film transistor 110 while maintaining the field of view. A structure that can improve the angular characteristics is shown. That is, in the structure of this embodiment mode, the thickness of the second base insulating film 102 and the gate insulating film 104 is set to be preferable for the operation of the thin film transistor, and the fourth insulating film 120 compensates for the insufficient thickness. Thus, both the characteristics of the thin film transistor and the viewing angle characteristics can be kept good.

  The first insulating film 106 has a physical thickness d of 132 nm to 198 nm, which is an optically laminated film including the second base insulating film 102, the gate insulating film 104, and the fourth insulating film 120. The reflected light can be significantly reduced by setting the physical thickness d of the first base insulating film 101 in the range of 120 nm to 162 nm. By reducing the reflected light, it is possible to suppress the occurrence of a standing wave caused by the interference between the incident light and the reflected light, and to suppress the deterioration of the viewing angle characteristics caused by the standing wave. . In addition, a display device with improved viewing angle characteristics can be manufactured.

  In the structure of this embodiment mode, an insulating film to be formed is increased by one layer, but the insulating film (fourth insulating film 120) is the same material as the second base insulating film 102 and the gate insulating film 104 or The number of optical layers is not changed by being formed of a material having the same refractive index or a material having a similar refractive index. Therefore, the stack of the second base insulating film 102 and the gate insulating film 104 in Embodiment 1 and the stack of the second base insulating film 102, the gate insulating film 104, and the fourth insulating film 120 in this embodiment are the same. It is possible to handle. Of course, if it is optically one layer, it can be handled in the same manner even if the number of layers is increased.

  Since other materials and configurations are the same as those in the first embodiment, refer to the description in the first embodiment.

  Note that the film thickness of each film is set so that the film thickness at the stage when the semiconductor device is completed becomes such a film thickness. In the case of actually manufacturing a semiconductor device, the film located under the film is reduced by etching for forming the semiconductor layer 103, the gate electrode 104, the electrodes 108 and 109, the first electrode 111 of the light emitting element, and the like. In some cases. In this case, in consideration of the film thickness reduction, it is necessary to adjust so that the film thickness reaches a specified thickness in a portion where the light from the light emitting element 115 hits the optical path when it is emitted to the outside of the display device. Can be done as appropriate. That is, according to the present invention, it is only necessary that the thickness of each layer in the portion corresponding to the optical path when light from the light emitting element 115 is emitted to the outside of the display device is as described above.

(Embodiment 7)
In this embodiment, another structure of the present invention will be described with reference to FIG. The display device in this embodiment is almost the same as the structure in Embodiment 1, but the second insulating film 107 formed of a coating film having self-flatness in Embodiment 1 has self-flatness. In this example, the fifth insulating film 121 is formed of another insulating material that is not included. Examples of the material of the fifth insulating film 121 include silicon oxide and silicon oxide containing nitrogen.

  In the display device in this embodiment having such a structure, the fifth insulating film 121, the first insulating film 106, and the gate insulating film 104 are emitted before light emitted from the light-emitting element 115 is emitted to the outside of the display device. , Passes through the second base insulating film 102, the first base insulating film 101, and the substrate 100. Among these, the first insulating film 106 and the first base insulating film 101 have a large difference in refractive index between the film sandwiching the film. Therefore, in this embodiment, the physical thickness d of the first insulating film 106 and the first base insulating film 101 is set to λm / 2n (m is an integer of 0 or more), that is, the first insulating film 106 and the first insulating film 106 By setting the optical thickness L of the base insulating film 101 to λm / 2 (m is an integer of 0 or more), the reflected light at the entrance side interface of the film is reflected by the reflected light at the exit side interface of the film. It becomes possible to attenuate, and the reflected light generated by the presence of the film can be significantly reduced. By reducing the reflected light, it is possible to suppress the occurrence of a standing wave caused by the interference between the incident light and the reflected light, and to suppress the deterioration of the viewing angle characteristics caused by the standing wave. . In addition, a display device with improved viewing angle characteristics can be manufactured.

  Alternatively, the optical thicknesses of the first insulating film 106 and the first base insulating film 101 are set to L1, respectively, and the optical thickness of the gate insulating film 104 between the first insulating film 106 and the first base insulating film 101 is set. Let L2 be a film thickness that satisfies L2 = −L1 + (2m−1) λ / 4. As a result, reflected light can be remarkably reduced, generation of standing waves caused by interference between incident light and reflected light can be suppressed, and deterioration of viewing angle characteristics caused by standing waves can be suppressed. It becomes possible. In addition, a display device with improved viewing angle characteristics can be manufactured.

  Alternatively, the physical thickness d of the first insulating film 106 and the first base insulating film 101 is set to be in a range of 120 nm to 162 nm, and one optical layer including the second base insulating film 102 and the gate insulating film 104 is used. The physical thickness d of a certain laminated film is in the range of 132 nm to 198 nm. As a result, reflected light can be remarkably reduced, generation of standing waves caused by interference between incident light and reflected light can be suppressed, and deterioration of viewing angle characteristics caused by standing waves can be suppressed. It becomes possible. In addition, a display device with improved viewing angle characteristics can be manufactured.

  Since other configurations are the same as those in the first embodiment, refer to the description in the first embodiment.

  Note that the film thickness of each film is set so that the film thickness at the stage when the semiconductor device is completed becomes such a film thickness. In the case of actually manufacturing a semiconductor device, the film located under the film is reduced by etching for forming the semiconductor layer 103, the gate electrode 104, the electrodes 108 and 109, the first electrode 111 of the light emitting element, and the like. In some cases. In this case, in consideration of the film thickness reduction, it is necessary to adjust so that the film thickness reaches a specified thickness in a portion where the light from the light emitting element 115 hits the optical path when it is emitted to the outside of the display device. Can be done as appropriate. That is, according to the present invention, it is only necessary that the thickness of each layer in the portion corresponding to the optical path when light from the light emitting element 115 is emitted to the outside of the display device is as described above.

(Embodiment 8)
In this embodiment, another structure of the present invention will be described with reference to FIG. The display device in this embodiment is almost the same as the structure in Embodiment 1, but the second insulating film 107 formed of a coating film having self-flatness in Embodiment 1 has self-flatness. The sixth insulating film 122 is formed of another insulating material that is not included, the first insulating film 106 is not formed, and the seventh insulating film 123 is the first light-emitting element. This is an example of being provided in contact with the electrode 111. Examples of the material of the sixth insulating film 1225 include silicon oxide and silicon oxide containing nitrogen, and examples of the material of the seventh insulating film 123 include silicon nitride and silicon nitride containing oxygen.

  In the display device in this embodiment having such a structure, the seventh insulating film 123, the sixth insulating film 122, and the gate insulating film 104 are emitted before light emitted from the light-emitting element 115 is emitted to the outside of the display device. , Passes through the second base insulating film 102, the first base insulating film 101, and the substrate 100.

In this case, a film having a different refractive index that passes through before the light emitted from the light emitting element 115 is emitted to the outside can be considered as one layer of the first base insulating film 101.

  Here, the optical thickness L of the first base insulating film 101 is approximately an integral multiple of λ / 2, where λ is the center wavelength of the light emitted from the light emitting element 115, so that The reflected light can be attenuated by the reflected light at the emission side interface of the film, and the reflected light generated by the presence of the film can be significantly reduced. By reducing the reflected light, it is possible to suppress the occurrence of a standing wave caused by the interference between the incident light and the reflected light, and to suppress the deterioration of the viewing angle characteristics caused by the standing wave. . In addition, a display device with improved viewing angle characteristics can be manufactured.

  Since other configurations are the same as those in the first embodiment, refer to the description in the first embodiment.

  Note that the film thickness of each film is set so that the film thickness at the stage when the semiconductor device is completed becomes such a film thickness. In the case of actually manufacturing a semiconductor device, the film located under the film is reduced by etching for forming the semiconductor layer 103, the gate electrode 104, the electrodes 108 and 109, the first electrode 111 of the light emitting element, and the like. In some cases. In this case, in consideration of the film thickness reduction, it is necessary to adjust so that the film thickness reaches a specified thickness in a portion where the light from the light emitting element 115 hits the optical path when it is emitted to the outside of the display device. Can be done as appropriate. That is, according to the present invention, it is only necessary that the thickness of each layer in the portion corresponding to the optical path when light from the light emitting element 115 is emitted to the outside of the display device is as described above.

(Embodiment 9)
In this embodiment mode, a method for manufacturing the light-emitting device of the present invention having the structure shown in Embodiment Mode 1 will be described with reference to FIGS.

  After the first base insulating film 101 and the second base insulating film 102 are formed over the substrate 100, a semiconductor film is further formed over the second base insulating film 102. (Fig. 6 (A))

  As a material for the substrate 100, light-transmitting glass, quartz, plastic (polyimide, acrylic, polyethylene terephthalate, polycarbonate, polyacrylate, polyethersulfone, or the like) can be used. These substrates may be used after being polished by CMP or the like, if necessary. In this embodiment, a glass substrate is used.

  The first base insulating film 101 and the second base insulating film 102 prevent an element such as an alkali metal or an alkaline earth metal in the substrate 100 that adversely affects the characteristics of the semiconductor film from diffusing into the semiconductor layer. Provided for this purpose. As a material, silicon oxide, silicon nitride, silicon oxide containing nitrogen, silicon nitride containing oxygen, or the like can be used.

  As described above, the first base insulating film 101 and the second base insulating film 102 are impurity elements (ions) that adversely affect the characteristics of the semiconductor film, such as alkali metals and alkaline earth metals in the substrate 100. However, it is known that a film containing silicon nitride as a main component has a large blocking effect of these impurity elements (ions). On the other hand, a film containing silicon oxide as a main component has a wider band gap, better insulation, and a lower trap order than a film containing silicon nitride as a main component.

  Therefore, in this embodiment mode, the first base insulating film 101 formed of silicon nitride containing oxygen and the second base insulating film 102 formed of silicon oxide containing nitrogen on the top are used for base insulation. A film is formed. Thus, a structure in which a high impurity element (ion) blocking effect and the reliability of the thin film transistor can be obtained at the same time is obtained.

  Note that the optical thickness L (L = refractive index n × physical thickness d) of the first base insulating film 101 is approximately λ /, where λ is the center wavelength of light emitted from a light emitting element to be formed later. The film is formed to an integral multiple of 2. In addition, even in the case of a display device having a plurality of types of light emitting elements having different center wavelengths, such as a full color display device with different colors, a display device using a white light emitting element, or the like, the light emitting element In the case of a display device having a plurality of maximum wavelengths with high intensity in the spectrum of light emitted from the first base insulating film 101, the physical thickness d is preferably 120 nm to 160 nm.

  The semiconductor film 118 formed subsequently is obtained by laser crystallization of an amorphous silicon film in this embodiment mode. An amorphous silicon film is formed with a thickness of 25 to 100 nm (preferably 30 to 60 nm) over the second base insulating film 102. The amorphous silicon film can be formed by a known method such as sputtering, low pressure CVD or plasma CVD. Then, hydrogen treatment is performed at 500 ° C. for 1 hour.

  Subsequently, the amorphous silicon film is crystallized using a laser irradiation apparatus to form a crystalline silicon film. In the laser crystallization of this embodiment, an excimer laser is used, and a laser beam oscillated is processed into a linear beam spot using an optical system and irradiated to an amorphous silicon film to form a crystalline silicon film. Used as the semiconductor film 118.

  Other crystallization methods for the amorphous silicon film include a method for crystallization only by heat treatment and a method for heat treatment using a catalyst element that promotes crystallization. Examples of elements that promote crystallization include nickel, iron, palladium, tin, lead, cobalt, platinum, gold, gold, etc. Compared to the case where crystallization is performed only by heat treatment by using such elements, Since crystallization is performed at a low temperature for a short time, there is little damage to the glass substrate. When crystallization is performed only by heat treatment, the substrate 100 must be a heat-resistant quartz substrate or the like.

  Subsequently, in order to control the threshold value of the semiconductor film 118 as necessary, a small amount of impurities are added, so-called channel doping. In order to obtain a required threshold value, N-type or P-type impurities (phosphorus, boron, etc.) are added by an ion doping method or the like.

  After that, as shown in FIG. 6B, the semiconductor film 118 is patterned into a predetermined shape, so that the semiconductor layer 103 is obtained. Patterning is performed by applying a photoresist to the semiconductor film 118, exposing a predetermined mask shape, baking, forming a resist mask over the semiconductor layer, and etching using the mask.

  Subsequently, a gate insulating film 104 is formed so as to cover the semiconductor layer 103. The gate insulating film 104 is formed of an insulating film containing silicon with a thickness of 40 to 150 nm by plasma CVD or sputtering. In this embodiment mode, the gate insulating film 104 is formed using the same material as the second base insulating film 102, or a material having the same refractive index or a material having substantially the same refractive index. The base insulating film 102 can be regarded as an optically single layer. In this embodiment, the second base insulating film 102 is formed using silicon oxide containing nitrogen, which is the same as the second base insulating film 102.

  Note that in this embodiment mode, the optical thickness L of the first base insulating film 101 and the first insulating film 106 is approximately an integral multiple of λ / 2, and thus the gate insulating film 104 and the second base insulating film Regarding the film thickness of 102, the display device to be manufactured is a single color display or a multicolor display using a color filter, and the maximum wavelength of light emitted from the light emitting element is single or the intensity of the maximum wavelength other than the center wavelength is small. In any film thickness, the viewing angle dependency is not adversely affected.

  However, even in the case of a display device having a plurality of types of light-emitting elements having different center wavelengths, such as a full-color display device with different colors or a display device using white light-emitting elements, the light-emitting element In the case of a display device having a plurality of maximum wavelengths with high intensity in the spectrum of light emitted from the light source, the total thickness of the second base insulating film 102 and the gate insulating film 104 is within a range of 130 nm to 200 nm. It is desirable to be.

  Next, the gate electrode 105 is formed over the gate insulating film 104. The gate electrode 105 may be formed of an element selected from Ta, W, Ti, Mo, Al, Cu, Cr, and Nd, or an alloy material or a compound material containing the element as a main component. Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus may be used. Further, an AgPdCu alloy may be used.

  In this embodiment mode, the gate electrode 105 is formed as a single layer; however, a stacked structure of two or more layers such as tungsten in the lower layer and molybdenum in the upper layer may be used. Even in the case where the gate electrode is formed as a stacked structure, the materials described in the preceding stage may be used. Moreover, the combination may be selected as appropriate.

  The gate electrode 105 is processed by etching using a mask using a photoresist.

  Subsequently, a high concentration impurity is added to the semiconductor layer 103 using the gate electrode 105 as a mask.

  In this embodiment mode, a top-gate thin film transistor using a crystalline silicon film crystallized by laser crystallization is used; however, a bottom-gate thin film transistor using an amorphous semiconductor film is used for a pixel portion. It is also possible. As the amorphous semiconductor, not only silicon but also silicon germanium can be used. When silicon germanium is used, the concentration of germanium is preferably about 0.01 to 4.5 atomic%.

  Alternatively, a microcrystalline semiconductor film (semi-amorphous semiconductor) in which crystals of 0.5 nm to 20 nm can be observed in an amorphous semiconductor may be used. Microcrystals capable of observing 0.5 nm to 20 nm crystals are also called so-called microcrystals (μc).

Semi-amorphous silicon (also referred to as SAS), which is a semi-amorphous semiconductor, can be obtained by glow discharge decomposition of a silicide gas. A typical silicide gas is SiH ₄ , and in addition, Si ₂ H ₆ , SiH ₂ Cl ₂ , SiHCl ₃ , SiCl ₄ , SiF _{4 and the} like can be used. The formation of the SAS can be facilitated by diluting the silicide gas with one or plural kinds of rare gas elements selected from hydrogen, hydrogen and helium, argon, krypton, and neon. It is preferable to dilute the silicide gas at a dilution ratio in the range of 10 times to 1000 times. The reaction generation of the film by glow discharge decomposition may be performed at a pressure in the range of 0.1 Pa to 133 Pa. The power for forming the glow discharge may be high frequency power of 1 MHz to 120 MHz, preferably 13 MHz to 60 MHz. The substrate heating temperature is preferably 300 ° C. or less, and a substrate heating temperature of 100 to 250 ° C. is suitable.

The SAS formed in this way has a Raman spectrum shifted to a lower wavenumber than 520 cm ⁻¹ , and diffraction peaks of (111) and (220), which are considered to be derived from the Si crystal lattice in X-ray diffraction, are observed. Is done. As a neutralizing agent for dangling bonds, hydrogen or halogen is contained at least 1 atomic%. As an impurity element in the film, impurities of atmospheric components such as oxygen, nitrogen, and carbon are desirably 1 × 10 ²⁰ cm ⁻¹ or less, and in particular, the oxygen concentration is 5 × 10 ¹⁹ / cm ³ or less, preferably 1 × 10 ¹⁹ / cm ³ or less. When the TFT is used, μ = 1 to 10 cm ² / Vsec.

  Further, this SAS may be further crystallized with a laser.

  Subsequently, a first insulating film 106 is formed using silicon nitride containing oxygen so as to cover the gate electrode 105 and the gate insulating film 104. (FIG. 6C) After the first insulating film 106 is formed, heating is performed at 480 ° C. for about 1 hour to activate the impurity element doped in the semiconductor layer 103 and at the same time included in the first insulating film 106. The semiconductor layer 103 is hydrogenated with the hydrogen that has been added.

  Here, the optical thickness L (L = refractive index n × physical thickness d) of the first insulating film is approximately λ / 2, where λ is the central wavelength of light emitted from the light emitting element to be formed later. Films are formed in integer multiples. In addition, even in the case of a display device having a plurality of types of light emitting elements having different center wavelengths, such as a full color display device with different colors, a display device using a white light emitting element, or the like, the light emitting element In the case of a display device having a plurality of maximum wavelengths with a high intensity in the spectrum of light emitted from the light, it is preferable to form the display at 120 to 160 nm.

  Subsequently, a second insulating film 107 that covers the first insulating film 106 is formed. As a material for forming the second insulating film 107, a coating film such as acrylic, polyimide, or siloxane having self-flatness can be preferably used. In this embodiment mode, siloxane is formed as the first interlayer insulating film. (Fig. 6 (D))

  Next, a contact hole reaching the semiconductor layer 103 is opened. 6E can be formed by performing etching using a resist mask until the semiconductor layer 103 is exposed, and can be formed by either wet etching or dry etching. Note that etching may be performed once depending on conditions, or etching may be performed in a plurality of times. In addition, when etching is performed a plurality of times, both wet etching and dry etching may be used.

Then, a conductive layer covering the contact hole and the second insulating film 107 is formed, the conductive layer is processed into a desired shape, and electrodes 108 and 109 and other wirings are formed. These electrodes and wirings may be a single layer of aluminum, copper, or the like, but in this embodiment mode, a stacked structure of molybdenum, aluminum, and molybdenum is formed from the substrate side. The laminated wiring may have a laminated structure of titanium, aluminum, titanium, titanium, titanium nitride, aluminum, titanium from the substrate side (FIG. 7A). At this stage, the thin film transistor 110 is formed.

  Note that the manufacturing process of the thin film transistor 110 is not particularly limited, and may be changed as appropriate so that a transistor with a desired structure can be manufactured.

  A light-transmitting conductive layer is formed so as to cover the electrodes 108 and 109, the wiring, and the second insulating film 107, and then the light-transmitting conductive layer is processed so that light emission partially overlaps the electrode 109. A first electrode 111 of the element is formed. Here, the first electrode 111 is in electrical contact with the electrode 109. As materials for the first electrode 111, indium tin oxide (ITO), ITO containing silicon oxide (ITSO), or IZO (Indium Zinc Oxide) containing 2 to 20% zinc oxide in indium oxide. Alternatively, zinc oxide itself, GZO (gallium zinc oxide) containing gallium in zinc oxide, or the like may be used. In this embodiment mode, ITSO is used as the first electrode 111. (Fig. 7 (B))

  Next, an insulating film made of an organic material or an inorganic material is formed so as to cover the second insulating film 107 and the first electrode 111. Subsequently, the insulating film is processed so that part of the first electrode 111 is exposed, so that the partition 112 is formed. As the material of the partition 112, a photosensitive organic material (acrylic, polyimide, or the like) is preferably used, but it may be formed of an organic material or an inorganic material that does not have photosensitivity. It is desirable that the end face of the partition wall 112 facing the first electrode 111 has a curvature, and has a tapered shape in which the curvature continuously changes. (Fig. 7 (C))

  Next, a light-emitting stacked body 113 that covers the first electrode 111 exposed from the partition 112 is formed. The light emitting laminate 113 may be formed by any method such as a vapor deposition method, an ink jet method, or a spin coating method. Subsequently, a second electrode 114 that covers the light-emitting stacked body 113 is formed. Thus, a light-emitting element 115 including the first electrode 111, the light-emitting stacked body 113, and the second electrode 114 can be manufactured (FIG. 7C).

  In the display device in this embodiment having such a structure, the second insulating film 107, the first insulating film 106, and the gate insulating film 104 are emitted before light emitted from the light-emitting element 115 is emitted to the outside of the display device. , Passes through the second base insulating film 102, the first base insulating film 101, and the substrate 100. Among these, the first insulating film 106 and the first base insulating film 101 have a large difference in refractive index between the film sandwiching the film. Therefore, in this embodiment, the optical thickness L of the first insulating film 106 and the first base insulating film 101 is approximately an integral multiple of λ / 2, where λ is the center wavelength of light emitted from the light emitting element 115. Thus, the reflected light at the incident side interface of the film can be attenuated by the reflected light at the output side interface of the film, and the reflected light generated due to the presence of the film can be significantly reduced. By reducing the reflected light, it is possible to suppress the occurrence of a standing wave caused by the interference between the incident light and the reflected light, and to suppress the deterioration of the viewing angle characteristics caused by the standing wave. . In addition, a display device with improved viewing angle characteristics can be manufactured.

After that, a silicon oxide film containing oxygen may be formed as a second passivation film by a plasma CVD method. When a silicon oxide film containing nitrogen is used, a film formed from SiH ₄ , N ₂ O, NH ₃ by a plasma CVD method, a film formed from SiH ₄ , N ₂ O, or SiH ₄ , N ₂ A film formed from a gas obtained by diluting O with Ar may be formed.

Alternatively, a silicon oxide film containing hydrogenated nitrogen manufactured from SiH ₄ , N ₂ O, and H ₂ may be used as the second passivation film. Of course, the second passivation film is not limited to a single layer structure, and another insulating film containing silicon may be used as a single layer structure or a laminated structure. Further, a multilayer film of carbon nitride film and silicon nitride film, a multilayer film of styrene polymer, a silicon nitride film, or a diamond-like carbon film may be formed instead of the silicon oxide film containing nitrogen.

  Subsequently, the display portion is sealed in order to protect the electroluminescent element from a substance that promotes deterioration such as water. In the case where the counter substrate is used for sealing, bonding is performed with an insulating sealing material so that the external connection portion is exposed. A space between the counter substrate and the element substrate may be filled with an inert gas such as dry nitrogen, or a seal material may be applied to the entire surface of the pixel portion to form the counter substrate. It is preferable to use an ultraviolet curable resin or the like for the sealing material. The sealing material may contain a desiccant and particles for keeping the gap constant. Subsequently, an electroluminescent device is completed by attaching a flexible wiring board to the external connection portion.

  Note that either an analog video signal or a digital video signal may be used in the light-emitting display device of the present invention having a display function. When a digital video signal is used, the video signal is classified into one using a voltage and one using a current. When the light emitting element emits light, the video signal input to the pixel has a constant voltage and a constant current. When the video signal has a constant voltage, the voltage applied to the light emitting element is constant. And the current flowing through the light emitting element is constant. In addition, a video signal having a constant current includes a constant voltage applied to the light emitting element and a constant current flowing in the light emitting element. A constant voltage applied to the light emitting element is constant voltage driving, and a constant current flowing through the light emitting element is constant current driving. In constant current driving, a constant current flows regardless of the resistance change of the light emitting element. Any of the above driving methods may be used for the light emitting display device and the driving method thereof of the present invention.

  Note that other structures of the present invention described in Embodiments 1 to 5 can be easily obtained by those skilled in the art by appropriately changing the manufacturing process described in this embodiment.

(Embodiment 10)
In this embodiment, the appearance of a panel of a light-emitting device that corresponds to one embodiment of the present invention will be described with reference to FIGS. 8 is a top view of a panel in which a transistor and a light-emitting element formed over a substrate are sealed with a sealant formed between a counter substrate 4006 and FIG. 8B is a cross-sectional view of FIG. It corresponds to. The configuration of the pixel portion of this panel has any of the configurations shown in the first to fifth embodiments.

  A sealant 4005 is provided so as to surround the pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004 which are provided over the substrate 4001. A counter substrate 4006 is provided over the pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004. Therefore, the pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004 are sealed together with the filler 4007 by the substrate 4001, the sealant 4005, and the counter substrate 4006.

  The pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004 provided over the substrate 4001 include a plurality of thin film transistors. In FIG. 8B, the thin film transistor 4008 included in the signal line driver circuit 4003 is provided. And a thin film transistor 4010 included in the pixel portion 4002.

  Reference numeral 4011 corresponds to a light-emitting element and is electrically connected to the thin film transistor 4010. Further, an opening 4009 is provided on the substrate 4001 side of the light emitting element, and a material having a significantly different refractive index is not formed on the optical path. For Embodiment 4009, refer to Embodiment Modes 1 to 6.

  A lead wiring 4014 corresponds to a wiring for supplying a signal or a power supply voltage to the pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004. The lead wiring 4014 is connected to the connection terminal 4016 through the lead wiring 4015. The connection terminal 4016 is electrically connected to a terminal included in a flexible printed circuit (FPC) 4018 through an anisotropic conductive film 4019.

  Note that as the filler 4007, in addition to an inert gas such as nitrogen or argon, an ultraviolet curable resin or a thermosetting resin can be used, and polyvinyl chloride, acrylic, polyimide, epoxy resin, silicon resin, polyvinyl butyral, Alternatively, ethylene vinylene acetate can be used.

  Note that the display device of the present invention includes in its category a panel in which a pixel portion having a light-emitting element is formed and a module in which an IC is mounted on the panel.

  In the panel and module described in this embodiment, the generation of a standing wave generated by interference between incident light and reflected light is suppressed until light emitted from the light emitting element 4011 is emitted to the outside of the display device. It is possible to suppress the deterioration of the viewing angle characteristics caused by this standing wave. In addition, a display device with improved viewing angle characteristics can be manufactured.

(Embodiment 11)
As an electronic device of the present invention in which a module whose example is shown in Embodiment 10 is mounted, a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproduction device (car audio component, etc.) A recording medium such as a computer, a game machine, a portable information terminal (mobile computer, cellular phone, portable game machine, electronic book, etc.), an image reproducing device (specifically Digital Versatile Disc (DVD)) equipped with a recording medium And a device having a display capable of reproducing and displaying the image). Specific examples of these electronic devices are shown in FIGS.

  FIG. 9A illustrates a light-emitting display device, such as a television receiver or a personal computer monitor. A housing 2001, a display portion 2003, a speaker portion 2004, and the like are included. In the light-emitting display device of the present invention, the change in the emission spectrum depending on the angle at which the light emission surface of the display unit 2003 is viewed is reduced, and the display quality is improved. In order to increase the contrast in the pixel portion, a polarizing plate or a circular polarizing plate may be provided. For example, a film may be provided on the sealing substrate in the order of a 1 / 4λ plate, a 1 / 2λ plate, and a polarizing plate. Further, an antireflection film may be provided on the polarizing plate.

  FIG. 9B illustrates a mobile phone, which includes a main body 2101, a housing 2102, a display portion 2103, an audio input portion 2104, an audio output portion 2105, operation keys 2106, an antenna 2108, and the like. In the mobile phone of the present invention, the change in the emission spectrum depending on the viewing angle of the light emission surface of the display portion 2103 is reduced, and the display quality is improved.

  FIG. 9C illustrates a computer, which includes a main body 2201, a housing 2202, a display portion 2203, a keyboard 2204, an external connection port 2205, a pointing mouse 2206, and the like. In the computer of the present invention, the change in the emission spectrum depending on the angle at which the light emission surface of the display portion 2203 is viewed is reduced, and the display quality is improved. Although a notebook computer is illustrated in FIG. 9C, the present invention can also be applied to a desktop computer in which a hard disk and a display portion are integrated.

  FIG. 9D illustrates a mobile computer, which includes a main body 2301, a display portion 2302, a switch 2303, operation keys 2304, an infrared port 2305, and the like. In the mobile computer of the present invention, the change in the emission spectrum depending on the viewing angle of the light emission surface of the display portion 2302 is reduced, and the display quality is improved.

  FIG. 9E illustrates a portable game machine including a housing 2401, a display portion 2402, speaker portions 2403, operation keys 2404, a recording medium insertion portion 2405, and the like. In the portable game machine of the present invention, the change in the emission spectrum depending on the angle at which the light emission surface of the display portion 2402 is viewed is reduced, and the display quality is improved.

As described above, the applicable range of the present invention is so wide that it can be used for electronic devices in various fields.
(Embodiment 12)

  In this embodiment, the structure of the light-emitting stacked body 113 will be described in detail.

  The light-emitting layer is formed of a charge injecting and transporting substance containing an organic compound or an inorganic compound and a light-emitting material. From the number of molecules thereof, a low molecular weight organic compound or a medium molecular weight organic compound (having no sublimation property and a molecular number of 20 Or an organic compound having a chain molecule length of 10 μm or less), including one or a plurality of layers selected from high-molecular organic compounds, and having an electron injection / transport property or a hole injection / transport property You may combine with a compound.

Among the charge injecting and transporting materials, materials having a particularly high electron transporting property include, for example, tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (5-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), Bis (10-hydroxybenzo [h] -quinolinato) beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), quinoline skeleton or benzoquinoline Examples thereof include metal complexes having a skeleton. As a substance having a high hole-transport property, for example, 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (abbreviation: α-NPD), 4,4′-bis [ N- (3-methylphenyl) -N-phenyl-amino] -biphenyl (abbreviation: TPD) or 4,4 ′, 4 ″ -tris (N, N-diphenyl-amino) -triphenylamine (abbreviation: TDATA) ), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenyl-amino] -triphenylamine (abbreviation: MTDATA) (ie, benzene ring-nitrogen) And a compound having a bond of

Among the charge injecting and transporting materials, materials having particularly high electron injecting properties include alkali metals or alkaline earths such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ) and the like. Metal compounds can be mentioned. In addition, a mixture of a substance having a high electron transport property such as Alq ₃ and an alkaline earth metal such as magnesium (Mg) may be used.

Among the charge injecting and transporting materials, examples of the material having a high hole injecting property include molybdenum oxide (MoOx), vanadium oxide (VOx), ruthenium oxide (RuOx), tungsten oxide (WOx), and manganese oxide. Examples thereof include metal oxides such as (MnOx). In addition, phthalocyanine compounds such as phthalocyanine (abbreviation: H ₂ Pc) and copper phthalocyanine (CuPC) can be given.

  The light emitting layer may be configured to perform color display by forming light emitting layers having different emission wavelength bands for each pixel. Typically, a light emitting layer corresponding to each color of R (red), G (green), and B (blue) is formed. In this case as well, by providing a filter (colored layer) that transmits light in the emission wavelength band on the light emission side of the pixel, the color purity is improved and the pixel portion is mirrored (reflected). Prevention can be achieved. By providing the filter (colored layer), it is possible to omit a circularly polarizing plate that has been conventionally required, and it is possible to eliminate the loss of light emitted from the light emitting layer. Furthermore, a change in color tone that occurs when the pixel portion (display screen) is viewed obliquely can be reduced.

There are various kinds of light emitting materials. In the low molecular weight organic light emitting material, 4-dicyanomethylene-2-methyl-6- [2- (1,1,7,7-tetramethyl-9-julolidyl) ethenyl] -4H-pyran (abbreviation: DCJT), 4-dicyanomethylene-2-t-butyl-6- [2- (1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCJTB), periflanthene, 2, 5-dicyano-1,4-bis [2- (10-methoxy-1,1,7,7-tetramethyljulolidin-9-yl) ethenyl] benzene, N, N′-dimethylquinacridone (abbreviation: DMQd) , Coumarin 6, Coumarin 545T, Tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), 9,9′-bianthryl, 9,10-diphenylanthracene (abbreviation: DPA) and 9,10-bis (2-naphthyl) Ant Sen (abbreviation: DNA), or the like can be used. Other substances may also be used.

  On the other hand, the high molecular organic light emitting material has higher physical strength than the low molecular weight material, and the durability of the device is high. In addition, since the film can be formed by coating, the device can be manufactured relatively easily. The structure of the light emitting element using the high molecular weight organic light emitting material is basically the same as that when the low molecular weight organic light emitting material is used, and is a structure of a cathode, an organic light emitting layer, and an anode from the semiconductor layer side. However, when forming a light emitting layer using a high molecular weight organic light emitting material, it is difficult to form a laminated structure as in the case of using a low molecular weight organic light emitting material. . Specifically, the structure is a cathode, a light emitting layer, a hole transport layer, and an anode from the semiconductor layer side.

  Since the light emission color is determined by the material for forming the light emitting layer, a light emitting element exhibiting desired light emission can be formed by selecting these materials. Examples of the polymer electroluminescent material that can be used for forming the light emitting layer include polyparaphenylene vinylene, polyparaphenylene, polythiophene, and polyfluorene.

  Examples of the polyparaphenylene vinylene include poly (paraphenylene vinylene) [PPV] derivatives, poly (2,5-dialkoxy-1,4-phenylene vinylene) [RO-PPV], poly (2- (2′- Ethyl-hexoxy) -5-methoxy-1,4-phenylenevinylene) [MEH-PPV], poly (2- (dialkoxyphenyl) -1,4-phenylenevinylene) [ROPh-PPV] and the like. Examples of polyparaphenylene include derivatives of polyparaphenylene [PPP], poly (2,5-dialkoxy-1,4-phenylene) [RO-PPP], poly (2,5-dihexoxy-1,4-phenylene). ) And the like. The polythiophene series includes polythiophene [PT] derivatives, poly (3-alkylthiophene) [PAT], poly (3-hexylthiophene) [PHT], poly (3-cyclohexylthiophene) [PCHT], poly (3-cyclohexyl). -4-methylthiophene) [PCHMT], poly (3,4-dicyclohexylthiophene) [PDCHT], poly [3- (4-octylphenyl) -thiophene] [POPT], poly [3- (4-octylphenyl) -2,2 bithiophene] [PTOPT] and the like. Examples of the polyfluorene series include polyfluorene [PF] derivatives, poly (9,9-dialkylfluorene) [PDAF], poly (9,9-dioctylfluorene) [PDOF], and the like.

  Note that when a hole-transporting polymer-based organic light-emitting material is sandwiched between an anode and a light-emitting polymer-based organic light-emitting material, hole injection properties from the anode can be improved. In general, an acceptor material dissolved in water is applied by spin coating or the like. In addition, since it is insoluble in an organic solvent, it can be stacked with the above-described light-emitting organic light-emitting material. Examples of the hole-transporting polymer organic light emitting material include a mixture of PEDOT and camphor sulfonic acid (CSA) as an acceptor material, a mixture of polyaniline [PANI] and polystyrene sulfonic acid [PSS] as an acceptor material, and the like. .

  The light emitting layer can be configured to emit monochromatic or white light. In the case of using a white light emitting material, color display can be made possible by providing a filter (colored layer) that transmits light of a specific wavelength on the light emission side of the pixel.

To form a light emitting layer that emits white light, for _{example, Alq 3, Alq 3, Alq} 3 doped with Nile Red which is partly red light emitting pigment, p-EtTAZ, by TPD (aromatic diamine) evaporation A white color can be obtained by sequentially laminating. In the case where the EL is formed by a coating method using spin coating, it is preferable that baking is performed by vacuum heating after coating. For example, a poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) aqueous solution (PEDOT / PSS) that acts as a hole injection layer is applied and baked on the entire surface, and then a luminescent center dye (1, 1,4,4-tetraphenyl-1,3-butadiene (TPB), 4-dicyanomethylene-2-methyl-6- (p-dimethylamino-styryl) -4H-pyran (DCM1), Nile Red, Coumarin 6 Etc.) A doped polyvinyl carbazole (PVK) solution may be applied to the entire surface and fired.

  The light emitting layer can also be formed as a single layer, and an electron transporting 1,3,4-oxadiazole derivative (PBD) may be dispersed in hole transporting polyvinyl carbazole (PVK). Further, white light emission can be obtained by dispersing 30 wt% PBD as an electron transporting agent and dispersing an appropriate amount of four kinds of dyes (TPB, coumarin 6, DCM1, Nile red). In addition to the light-emitting element that can emit white light as shown here, a light-emitting element that can obtain red light emission, green light emission, or blue light emission can be manufactured by appropriately selecting the material of the light-emitting layer.

  Note that when a hole-transporting polymer-based organic light-emitting material is sandwiched between an anode and a light-emitting polymer-based organic light-emitting material, hole injection properties from the anode can be improved. In general, an acceptor material dissolved in water is applied by spin coating or the like. In addition, since it is insoluble in an organic solvent, it can be stacked with the above-described light-emitting organic light-emitting material. Examples of the hole-transporting polymer organic light emitting material include a mixture of PEDOT and camphor sulfonic acid (CSA) as an acceptor material, a mixture of polyaniline [PANI] and polystyrene sulfonic acid [PSS] as an acceptor material, and the like. .

  Furthermore, a triplet excitation material containing a metal complex or the like may be used for the light emitting layer in addition to a singlet excitation light emitting material. For example, among red light emitting pixels, green light emitting pixels, and blue light emitting pixels, a red light emitting pixel having a relatively short luminance half time is formed of a triplet excitation light emitting material, and the other A singlet excited luminescent material is used. The triplet excited luminescent material has a feature that the light emission efficiency is good, so that less power is required to obtain the same luminance. That is, when applied to a red pixel, the amount of current flowing through the light emitting element can be reduced, so that reliability can be improved. As a reduction in power consumption, a red light-emitting pixel and a green light-emitting pixel may be formed using a triplet excitation light-emitting material, and a blue light-emitting pixel may be formed using a singlet excitation light-emitting material. By forming a green light-emitting element having high human visibility with a triplet excited light-emitting material, power consumption can be further reduced.

  Examples of triplet excited luminescent materials include those using a metal complex as a dopant, and metal complexes having a third transition series element platinum as the central metal and metal complexes having iridium as the central metal are known. Yes. The triplet excited light-emitting material is not limited to these compounds, and a compound having the above structure and having an element belonging to group 8 to 10 in the periodic table as a central metal can also be used.

  The substances forming the light-emitting layer listed above are examples, and functionalities such as a hole injection transport layer, a hole transport layer, an electron injection transport layer, an electron transport layer, a light emission layer, an electron block layer, and a hole block layer are included. A light emitting element can be formed by appropriately stacking each layer. Moreover, you may form the mixed layer or mixed junction which combined these each layer. The layer structure of the light-emitting layer can be changed, and instead of having a specific electron injection region or light-emitting region, it is possible to provide a modification with an electrode for this purpose or a dispersed light-emitting material. Can be permitted without departing from the spirit of the present invention.

A light-emitting element formed using the above materials emits light by being forward-biased. A pixel of a display device formed using a light-emitting element can be driven by a simple matrix method or an active matrix method. In any case, each pixel emits light by applying a forward bias at a specific timing, but is in a non-light emitting state for a certain period. By applying a reverse bias during this non-light emitting time, the reliability of the light emitting element can be improved. The light emitting element has a degradation mode in which the light emission intensity decreases under a constant driving condition and a degradation mode in which the non-light emitting area is enlarged in the pixel and the luminance is apparently decreased. However, alternating current that applies a bias in the forward and reverse directions. By performing a typical drive, the progress of deterioration can be slowed and the reliability of the light emitting device can be improved.
(Embodiment 13)

  In this embodiment mode, pixel circuits and protection circuits included in the panel and module described in Embodiment Mode 10 and operations thereof will be described. Note that the cross-sectional views shown in FIGS. 1 to 7 are cross-sectional views of the driving TFT 1403 and the light emitting element 1405.

  In the pixel shown in FIG. 10A, a signal line 1410 and power supply lines 1411 and 1412 are arranged in the column direction, and a scanning line 1414 is arranged in the row direction. The pixel further includes a switching TFT 1401, a driving TFT 1403, a current control TFT 1404, a capacitor element 1402, and a light emitting element 1405.

  The pixel shown in FIG. 10C is different from the pixel shown in FIG. 10A except that the gate electrode of the driving TFT 1403 is connected to the power supply line 1412 arranged in the row direction. It is a configuration. That is, both pixels shown in FIGS. 10A and 10C show the same equivalent circuit diagram. However, in the case where the power supply line 1412 is arranged in the row direction (FIG. 10A) and in the case where the power supply line 1412 is arranged in the column direction (FIG. 10C), each power supply line has a different layer. It is formed of a conductive film. Here, attention is paid to the wiring to which the gate electrode of the driving TFT 1403 is connected, and FIGS. 10A and 10C are shown separately to show that layers for manufacturing these are different.

  As a feature of the pixel shown in FIGS. 10A and 10C, a driving TFT 1403 and a current control TFT 1404 are connected in series in the pixel, and the channel length L (1403) and channel width W (1403) of the driving TFT 1403 are connected. ), The channel length L (1404) and the channel width W (1404) of the current control TFT 1404 satisfy L (1403) / W (1403): L (1404) / W (1404) = 5 to 6000: 1. It is good to set to.

  Note that the driving TFT 1403 operates in a saturation region and has a role of controlling a current value flowing through the light emitting element 1405, and the current control TFT 1404 operates in a linear region and has a role of controlling supply of current to the light emitting element 1405. . Both TFTs preferably have the same conductivity type in terms of manufacturing process, and in this embodiment mode, they are formed as n-channel TFTs. The driving TFT 1403 may be a depletion type TFT as well as an enhancement type. In the present invention having the above configuration, since the current control TFT 1404 operates in a linear region, a slight change in Vgs of the current control TFT 1404 does not affect the current value of the light emitting element 1405. That is, the current value of the light emitting element 1405 can be determined by the driving TFT 1403 operating in the saturation region. With the above structure, it is possible to provide a display device in which luminance unevenness of a light-emitting element due to variation in TFT characteristics is improved and image quality is improved.

  In the pixel shown in FIGS. 10A to 10D, the switching TFT 1401 controls input of a video signal to the pixel. When the switching TFT 1401 is turned on, the video signal is input into the pixel. Then, the voltage of the video signal is held in the capacitor element 1402. Note that FIGS. 10A and 10C illustrate the structure in which the capacitor 1402 is provided; however, the present invention is not limited to this, and the capacity for holding a video signal can be covered by a gate capacity or the like. In this case, the capacitor 1402 is not necessarily provided.

  The pixel shown in FIG. 10B has the same pixel structure as that shown in FIG. 10A except that a TFT 1406 and a scanning line 1414 are added. Similarly, the pixel illustrated in FIG. 10D has the same pixel structure as that illustrated in FIG. 10C except that a TFT 1406 and a scanning line 1414 are added.

  The TFT 1406 is controlled to be turned on or off by a newly arranged scanning line 1414. When the TFT 1406 is turned on, the charge held in the capacitor element 1402 is discharged, and the current control TFT 1404 is turned off. That is, the arrangement of the TFT 1406 can forcibly create a state where no current flows through the light-emitting element 1405. Therefore, the TFT 1406 can be called an erasing TFT. 10B and 10D, the lighting period can be started at the same time as or immediately after the start of the writing period without waiting for signal writing to all pixels, so that the duty ratio is improved. It becomes possible.

  In the pixel illustrated in FIG. 10E, a signal line 1410, a power supply line 1411 are arranged in the column direction, and a scanning line 1414 is arranged in the row direction. Further, the pixel includes a switching TFT 1401, a driving TFT 1403, a capacitor element 1402, and a light emitting element 1405. The pixel illustrated in FIG. 10F has the same pixel structure as that illustrated in FIG. 7E except that a TFT 1406 and a scanning line 1415 are added. Note that the duty ratio of the structure in FIG. 10F can also be improved by the arrangement of the TFT 1406.

  As described above, various pixel circuits can be employed. In particular, when a thin film transistor is formed from an amorphous semiconductor film, it is preferable to increase the semiconductor film of the driving TFT. Therefore, it is preferable that the pixel circuit be a top emission type in which light from the electroluminescent layer is emitted from the sealing substrate side.

  Such an active matrix light-emitting device is considered to be advantageous because it can be driven at a low voltage because a TFT is provided in each pixel when the pixel density is increased.

  In this embodiment mode, an active matrix light-emitting device in which each pixel is provided with each TFT has been described; however, a passive matrix light-emitting device in which a TFT is provided for each column can also be formed. A passive matrix light-emitting device has a high aperture ratio because a TFT is not provided for each pixel. In the case of a light-emitting device in which light emission is emitted to both sides of an electroluminescent layer, transmittance using a passive matrix display device is increased.

The display device of the present invention further including such a pixel circuit has good viewing angle dependency, can maintain the characteristics of the thin film transistor, and can have a display device having each characteristic.

  Next, the case where a diode is provided as a protection circuit in the scan line and the signal line will be described using the equivalent circuit illustrated in FIG.

  In FIG. 11, switching TFTs 1401 and 1403, a capacitor element 1402, and a light emitting element 1405 are provided in the pixel portion 1500. The signal line 1410 is provided with diodes 1561 and 1562. Similarly to the switching TFT 1401 or 1403, the diodes 1561 and 1562 are manufactured based on the above embodiment mode and include a gate electrode, a semiconductor layer, a source electrode, a drain electrode, and the like. The diodes 1561 and 1562 operate as diodes by connecting a gate electrode and a drain electrode or a source electrode.

  Common potential lines 1554 and 1555 connected to the diode are formed in the same layer as the gate electrode. Therefore, in order to connect to the source electrode or drain electrode of the diode, it is necessary to form a contact hole in the gate insulating film.

  A diode provided in the scan line 1414 has a similar structure.

  Thus, according to the present invention, the protection diode provided in the input stage can be formed simultaneously. Note that the position where the protective diode is formed is not limited to this, and the protective diode can be provided between the driver circuit and the pixel.

  The display device of the present invention having such a protection circuit has good viewing angle dependency, can maintain the characteristics of the thin film transistor, and can also improve the reliability as a display device.

  In this example, FIG. 14 shows the results of manufacturing a display device of the present invention having light emitting elements each using two types of DMQd (green) and DNA (blue) as emission centers and measuring viewing angle characteristics. In this example, an element having the structure of Embodiment Mode 1 was manufactured and measured. Both elements have a physical thickness of 130 nm corresponding to the first base insulating film 101 and the first insulating film 106 in Embodiment Mode 1, and correspond to the second base insulating film 102 and the gate insulating film 104. The physical thickness obtained by adding the film thickness was set to 150 nm.

  As a comparative example, in both light emitting elements using DMQd (green) or DNA (blue), the physical thickness of the first base insulating film 101 is 50 nm, and the physical thickness of the first insulating film 106 is A display device was used in which the physical thickness obtained by adding the film thicknesses corresponding to 100 nm, the second base insulating film 102, and the gate insulating film 104 to 150 nm was used.

  FIG. 14A shows an example of measurement of a display device having DMQd (green) as the emission center, and FIG. 14B shows an example of measurement of a display device having DNA (blue) as the emission center. In both the ideal states, the intensity of the spectrum is not changed even if the viewing angle is changed. However, in the comparative example, it can be seen that the shape of the spectrum changes greatly depending on the viewing angle, and the viewing angle characteristics are not so good. However, in the configuration of the example, a large spectrum shape difference is not observed depending on the viewing angle, and it can be seen that the viewing angle characteristic is greatly improved as compared with the comparative example.

  As described above, the display device having the structure of the present invention has a large difference in refractive index between the light emitted from the light emitting element and the film sandwiching the film among the layers through which the light is emitted. By making the film thickness of the film having a specific film thickness, reflection of light generated when passing through the film having the large refractive index difference is suppressed. As a result, it is possible to suppress the occurrence of standing waves that appear due to interference between the reflected light and the incident light, and to improve the viewing angle dependency. Accordingly, it is possible to provide a display device that can perform good display with improved viewing angle characteristics.

Sectional drawing showing the display apparatus of this invention. Sectional drawing showing the display apparatus of this invention. Sectional drawing showing the display apparatus of this invention. Sectional drawing showing the display apparatus of this invention. Sectional drawing showing the display apparatus of this invention. Sectional drawing showing the manufacturing process of the display apparatus of this invention. Sectional drawing showing the manufacturing process of the display apparatus of this invention. 4A and 4B are a top view and a cross-sectional view illustrating a display device of the present invention. FIG. 14 illustrates an electronic device of the invention. FIG. 6 is a circuit diagram of a pixel circuit used in the display device of the present invention. The circuit diagram of the protection circuit used for the display apparatus of this invention. The figure which shows the simulation result of the reflectance in monochromatic light. The figure which shows the simulation result of the reflectance in a full color. Spectral measurement data representing viewing angle characteristics. Sectional drawing showing the display apparatus of this invention. Sectional drawing showing the display apparatus of this invention.

Claims (6)

A thin film transistor;
A lower electrode electrically connected to the thin film transistor and having a light-transmitting property; a layer including a light emitting material provided on the lower electrode; and an upper electrode provided on the layer including the light emitting material. A light emitting element,
Under the lower electrode, at least a first insulating film that can be optically regarded as one layer, a second insulating film that is in contact with the first insulating film and optically regarded as one layer, and A third insulating film that is in contact with the second insulating film and optically regarded as a single layer;
The refractive index of the second insulating film is larger or smaller than the refractive index of the first insulating film refractive index and the third insulating film,
m a natural number, the center wavelength of the light emitted from the layer containing the λ light emitting material, the optical thickness of the second insulating film L1, the optical thickness of the first insulating film and the third insulating film A display device characterized in that the relationship is approximately satisfying the expression of L1 + L2 = (2m−1) λ / 4, where L2 is L2. A glass substrate;
A first insulating film provided on the glass substrate;
A second insulating film provided on the first insulating film;
A semiconductor film provided on the second insulating film;
A third insulating film provided on the semiconductor film;
A gate electrode provided on the third insulating film;
A fourth insulating film provided on the gate electrode;
A light emitting element provided on the fourth insulating film,
The first insulating film and the fourth insulating film are formed of a material mainly composed of silicon nitride,
The second insulating film and the third insulating film are formed of a material mainly composed of silicon oxide,
The lower electrode of the light emitting element has translucency,
An insulating film stack including the first insulating film, the second insulating film, the third insulating film, and the fourth insulating film is provided under the light emitting element. And
m is a natural number, λ is the center wavelength of light emitted from the light emitting element, and the sum of the optical thickness of the second insulating film and the optical thickness of the third insulating film is L1, the first insulating film and A display device characterized in that when the optical thickness of the fourth insulating film is L2, the relation of L1 + L2 = (2m−1) λ / 4 is substantially satisfied. In claim 2,
A display device, wherein a coating film is formed between the fourth insulating film and the light emitting element. A thin film transistor;
A lower electrode electrically connected to the thin film transistor and having a light-transmitting property; a layer including a light emitting material provided on the lower electrode; and an upper electrode provided on the layer including the light emitting material. A light emitting element,
Under the lower electrode, at least a first insulating film that can be optically regarded as one layer, a second insulating film that is in contact with the first insulating film and optically regarded as one layer, and A third insulating film that is in contact with the second insulating film and optically regarded as a single layer;
The refractive index of the second insulating film, a manufacturing method of the first insulating film refractive index and the third insulating film larger or smaller display devices than the refractive index of,
m a natural number, the center wavelength of the light emitted from the layer containing the λ light emitting material, the optical thickness of the second insulating film L1, the optical thickness of the first insulating film and the third insulating film When the thicknesses are L2, the physical thicknesses of the first to third insulating films are adjusted so that the relation of L1 + L2 = (2m−1) λ / 4 is satisfied. A method for manufacturing a display device, comprising forming first to third insulating films. A glass substrate;
A first insulating film provided on the glass substrate;
A second insulating film provided on the first insulating film;
A semiconductor film provided on the second insulating film;
A third insulating film provided on the semiconductor film;
A gate electrode provided on the third insulating film;
A fourth insulating film provided on the gate electrode;
A light emitting element provided on the fourth insulating film,
The first insulating film and the fourth insulating film are formed of a material mainly composed of silicon nitride,
The second insulating film and the third insulating film are formed of a material mainly composed of silicon oxide,
The lower electrode of the light emitting element has translucency,
An insulating film stack including the first insulating film, the second insulating film, the third insulating film, and the fourth insulating film is provided under the light emitting element. A display device manufacturing method comprising:
m is a natural number, λ is the center wavelength of light emitted from the light emitting element, and the sum of the optical thickness of the second insulating film and the optical thickness of the third insulating film is L1, the first insulating film and When the optical thickness of the fourth insulating film is L2, respectively, the physical properties of the first to fourth insulating films are set so as to satisfy the relation of L1 + L2 = (2m−1) λ / 4. A method for manufacturing a display device, wherein the first to fourth insulating films are formed by adjusting a thickness of a film. In claim 5,
A method for manufacturing a display device, wherein a coating film is formed between the fourth insulating film and the light-emitting element.