JP2003076302A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device in which visibility is made superior in a room as well as in the open air while attaining its small size and reduction of the cost. SOLUTION: A reflection region 11 and a transmission region 12 are arranged together in a display pixel. The region 11 is made of non-light emitting display elements and liquid crystal display elements 20 reflect external light beams 4 to conduct displaying. The region 12 is made of light emitting display elements and organic EL light emitting elements 40 conduct displaying by direct modulation. Note that the device is provided with an insulation substrate 21 and an insulation substrate 29 which are mutually opposed to each other. The elements 20 and 40 are provided between the substrates 21 and 29. In the region 12, the elements 40 and a liquid crystal layer 26 of the elements 20 are successively laminated on the substrate 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-light emitting display device such as a liquid crystal display device and a display device such as a light emitting display device using an organic EL light emitting element. More specifically, the present invention relates to a display device in which a non-light emitting display area and a light emitting display area are provided side by side in the display area.

[0002]

2. Description of the Related Art In recent years, portable information terminals (PDA: Personal Data Assistant) and the like have become widespread, including mobile phones. Along with this, the development of displays for displaying information mounted on these terminals has become very active in recent years.

The above display is roughly classified into a non-light emitting display device and a light emitting display device. The former is to display by modulating light from an external light source such as sunlight, room light, a backlight or a front light by a light modulator.
A liquid crystal display element is known as a typical example. On the other hand, the latter does not require an external light source and the light-emitting element emits light by itself to perform display.
L (Electro Luminesence) is receiving much attention. Hereinafter, these display devices will be described in more detail.

First, in a transmissive liquid crystal display device which is a non-emissive display device using an external light source, since a backlight is used as a light source, power consumption is increased and the shape is enlarged, which leaves a problem for portable use. Therefore, in order to suppress the power consumption, which is one of the above problems, the lower electrode of the liquid crystal layer is formed of a metal such as aluminum that reflects light, and thus outside light such as sunlight or an interior light is used as a light source. A reflective liquid crystal display device has been developed. However, this reflective liquid crystal display device is difficult to use in a dark place because it utilizes outside light.

In order to solve such a problem, the lower electrode of the liquid crystal layer is formed by a half mirror so that reflective display is performed without using a backlight in a bright environment, and the backlight is turned on in a dark place to transmit the light. A transflective display device for displaying has been developed. However, in the above-mentioned semi-transmissive display device, since the characteristics of the light-reflecting portion and the light-transmitting portion are contradictory to each other, the light utilization efficiency is low and the decisive improvement for power consumption reduction has not been achieved.

In order to solve such a problem, the inventors of the present invention can use the backlight as a reflective type without using a backlight in a bright environment, and can use the backlight as a transmissive type in a dark place. A liquid crystal display device was devised (see Japanese Patent Application Laid-Open No. 11-101992). This liquid crystal display device is different from a conventional liquid crystal display device that uses a reflector having a thin film thickness and semi-transparency, and each display pixel in the liquid crystal display device has two regions, a reflective region and a transmissive region. Is divided into That is, in the liquid crystal display device described above, the reflective electrode is formed as one area of each display pixel to form a reflective area, while the transmissive electrode is formed in the other area of each display pixel to form a transmissive area. Also,
The thickness of the liquid crystal layer in the reflective region is different from the thickness of the liquid crystal layer in the transmissive region. This makes it possible to achieve optimum brightness in each of the reflective area and the transmissive area.

However, in the above-mentioned pixel division type liquid crystal display device, while backlight light is applied to the entire area of each pixel from the rear side, this backlight light is utilized only in the transmissive area of each pixel. Is. Therefore, there is a problem that the utilization efficiency of the backlight light is low.
In particular, when the area ratio of the reflective electrode is high, the transmissive area inevitably becomes narrow, so that the utilization efficiency of the backlight light becomes low.

Therefore, as a means for improving the utilization efficiency of the backlight of the pixel division type liquid crystal display device, for example, there is a pixel division type liquid crystal display device disclosed in Japanese Patent Laid-Open No. 2001-66593. . In the liquid crystal display device 100, as shown in FIG. 15, first, the reflective electrodes 10 arranged in the respective pixels 102 ... In the liquid crystal panel 101.
A pixel division type liquid crystal display device is provided by providing a transparent opening 104 ... Further, in the liquid crystal display device 100, an organic EL (Electrical display) is used as a backlight.
ro Luminesence) While using a light emitting element including an element 110, the light emitting portions 111 of the organic EL element 110 are not arranged in the entire area of each pixel 102, but only in the area corresponding to the transmissive opening 104. It is arranged. As a result, the patterned organic EL element is combined as a backlight, so that the light utilization efficiency can be improved and the power consumption can be reduced.

On the other hand, a display device using the above-mentioned organic EL light-emitting element, which is a typical light-emitting display device, has a feature of being thin and lightweight, and since it is a light-emitting element, it does not require a backlight like a liquid crystal display device and is in a dark environment. However, it can be used, and since almost all of the emitted light is used for display, the light utilization efficiency is high. However, a display device using this organic EL light emitting element needs to always emit light, and it is necessary to increase the light emission amount to improve the display quality especially in a bright environment, and thus it is difficult to reduce the power consumption. It was

[0010]

However, in the pixel division type liquid crystal display device shown in FIG. 15, the organic EL element 110 as a light emitting element is provided outside the liquid crystal panel 101.
The transparent aperture 1 of the reflective electrode 103
04 and the organic EL element 110, a retardation plate 105, a polarizing plate 106, two glass substrates, that is, a glass substrate 107.
And a glass substrate 112. At present, a general pixel pitch is about 80 μm, but in this case, the width of the transmissive opening 104 is 1/2 to 1/6 of that.
It is approximately 15 to 40 microns. On the other hand, the polarizing plate 106 has a thickness of about 300 μm, and there are two pieces of glass having a thickness of 500 to 700 μm, that is, the glass substrate 107 of the liquid crystal panel 101 and the glass substrate 112 of the organic EL element 110. Therefore, the distance between the transmissive opening 104 of the reflective electrode 103 and the organic EL element 110 is 1300 to 1700 microns. Therefore, even if the light emitting parts 111 of the organic EL element 110 are installed at the positions corresponding to the transmissive openings 104, all the light emitted from the light emitting parts 111 of the organic EL element 110 is incident on the transmissive openings 104. Is impossible. Therefore, again, there is a problem that the irradiation efficiency of the organic EL element 110 is not good.

The present invention has been made in view of the above conventional problems, and an object thereof is to provide a display device which is excellent in visibility from the outdoors to the indoors while achieving downsizing and cost reduction. is there.

[0012]

In order to solve the above-mentioned problems, a display device of the present invention comprises a first non-light-emitting display element in which a light modulation element reflects outside light in a display area to perform display. The light modulating element is provided with a display area and a second display area formed of a light emitting display element that is directly modulated by the light emitting element and has a first substrate and a second substrate facing each other. And the light emitting element are both provided between the first substrate and the second substrate, and in the second display area, the light emitting element and the light modulation layer of the light modulation element are sequentially provided on the first substrate. It is characterized by being laminated.

According to the display device of the present invention, a non-emissive display element that reflects external light for displaying and a self-emissive light emitting display element are incorporated in the same display device, so that a backlight or the like is provided. Since it is not necessary to additionally provide a separate light source, it is possible to realize low power consumption and miniaturization at the same time. Further, when a non-emissive display element and a self-emissive light emitting display element are incorporated in the same display device, the manufacturing process of members such as electrodes, wirings, drive elements, insulators, etc. can be made common, so that conventional backlights and the like can be used. The time and cost required for manufacturing and assembling the light source can be greatly reduced.

The operation and effect of the present invention will be described in detail below.

First, as described above, the display is generally classified into a non-light emitting display device and a light emitting display device.
A non-emissive display device is a device that modulates light from an external light source such as sunlight, room light, a backlight, and a front light by transmitting the light to an optical modulator that is a non-emissive display element. There are a reflection type having a reflection means for reflecting light from an external light source and a transmission type having no reflection means. On the other hand, a light emitting display device is a display device having a light emitting element. Usually, a portion called a light emitting element or a light emitting layer emits light by itself. Here, the control of the transmitted light in the light modulation element is referred to as light modulation, whereas the light emission from the light emitting element is referred to as direct modulation.

By the way, in the case of a transmissive non-emissive display device represented by a transmissive liquid crystal display device, the brightness of the backlight light is usually constant from dark display to bright display and is always on. Therefore, the transmissive non-emissive display device always consumes power from the external light source. Further, in the transmissive non-emissive display device, since it is necessary to supply power and control to the light modulation element and the backlight, respectively, the number of components is large, there is a limit to miniaturization, and cost reduction is aimed at. It was difficult.

On the other hand, a light emitting display device typified by an EL display device has different power consumptions for dark display and bright display because the light emission luminance is modulated, and the power consumption is small for dark display and large for bright display.

Here, the present invention is compared with the case where the transmissive non-emissive display element or the emissive display element and the reflective non-emissive display element are incorporated in the same panel and both are used for display. That is, the conventional display device incorporating the transmissive non-emissive display element and the reflective non-emissive display element, that is, the pixel division type liquid crystal display device described as the prior art is compared with the display device of the present invention. .

As shown by a broken line L1 in FIG. 2, the conventional liquid crystal display device requires a substantially constant power consumption because the backlight, which is a light source, needs to be constantly turned on from a bright environment to a dark environment. On the other hand, the display device of the present invention, in which the light emitting display element and the reflective non-light emitting display element are incorporated in the same panel, can display by adjusting the brightness of the light emitting display element according to the surrounding environment. Therefore, as indicated by the solid line L2 in FIG. 2, the light emission brightness is reduced in a bright environment, and the reflective non-light emitting display element can be used to the maximum, while the light emission display element is increased in a dark environment for display. can do. Therefore, in a bright environment, the power required for lighting the backlight in the conventional transmissive non-luminous display device can be suppressed to a low level.

Therefore, the display device of the present invention can achieve lower power consumption in a bright environment than a display device incorporating a transmissive non-emissive display element and a reflective non-emissive display element. By displaying with reduced brightness, it is possible to realize a long life and improved reliability. Further, since the display device of the present invention does not need to be provided with a backlight as a separate body, it can be made thinner and smaller than a conventional liquid crystal display device, and power supply means and control are not required. Therefore, the cost can be reduced.

A comparison of the display device according to the present invention with a display device having only a light emitting display element is as shown in FIG. That is, as indicated by a broken line L1 ′ in FIG. 3, in the case of a display device configured by only a light emitting display element, the display becomes difficult to see unless the emission brightness is increased as the environment becomes brighter.

On the other hand, in the display device of the present invention, the reflective non-light-emitting display element improves the display characteristics in a bright environment, and therefore the light-emitting display element has reduced brightness as shown by the solid line L2 'in the figure. Can be displayed. This is a concept that has not existed when used only in the conventional light emitting display element, and is a brightness control method that can be uniquely implemented by the configuration of the present invention.

Thus, according to the display device of the present invention,
It is possible to set the maximum brightness lower than that when only the light emitting display element is used, and it is possible to realize a long life and improved reliability.

Specifically, the display device of the present invention is as follows.
Within the display area, there are a first display area formed of a non-light emitting display element in which the light modulation element reflects external light to perform display, and a second display area formed of a light emitting display element in which the light emitting element directly modulates to display. It is annexed.

Therefore, since the light emitting element emits light itself toward the display surface side to directly display, the light emitting element is not used as a backlight or a front light as in the conventional case. As a result, the utilization efficiency of light from the light emitting element can be improved, and the thickness of the display device can be reduced. That is, the thickness of the backlight is usually 3 to
Since it is about 6 mm, the advantage of reducing the thickness by eliminating the need for a backlight is very large.
Further, the need for a backlight means that a polarizing plate, a retardation plate, and a glass substrate, which are conventionally installed between the back panel of the liquid crystal panel and the backlight, are also unnecessary. Therefore, the thickness of the display device can be further reduced by eliminating the need for these polarizing plate, retardation plate and glass substrate.

Further, since it is not necessary to position and fix the patterned light emitting element backlight, a dedicated device and a fixing mechanism therefor can be omitted, and the cost can be reduced by reducing the number of parts and the process. It will be possible.

Further, the merit that the backlight, the polarizing plate and the retardation plate on the back side are not necessary is not only the reduction in the thickness of the entire display device. That is, the reduction in the number of members can reduce not only the material cost but also the number of assembling steps and the cost required for inspecting each member, so that the manufacturing cost of the entire display device can be reduced.

Further, in the display device of the display area dividing method such as the pixel dividing method as in the present invention, the ratio of the first display area and the second display area can be designed to some extent. Therefore, for example, when it is premised on the use in a mobile device such as a mobile phone or a personal digital assistant (PDA), it is general to increase the ratio of the first display area which is a reflective area. For example, when 80% of the pixel area of the display pixel is the reflective area, the second display area, which is the light emitting area, is 20%, so the light emitting area of the light emitting element is 1/5 of the pixel area at the maximum. It's done. This means that it is possible to reduce power consumption.

Therefore, it is possible to provide a display device which is excellent in visibility from outdoors to indoors while achieving downsizing and cost reduction.

Further, in the present invention, a first substrate and a second substrate facing each other are provided, and the light modulation element and the light emitting element are both provided between the first substrate and the second substrate. There is. In the second display area, the light emitting element and the light modulation layer of the light modulation element are sequentially stacked on the first substrate. Therefore, both the light modulation element and the light emitting element are housed between the first substrate and the second substrate, so that the thickness of the display device can be surely reduced. Further, even if the light modulation layer is laminated on the surface side of the light emitting element, the light emitting element is provided between the first substrate and the second substrate,
All the display light of the light emitting element is emitted to the second display area. Therefore, the utilization efficiency of light becomes very high.

Therefore, it is possible to provide a display device capable of ensuring higher irradiation efficiency and improving not only the brightness but also the thickness of the display device and the cost of members.

Further, the display device of the present invention is characterized in that, in the display device described above, the light emitting element has an area which is substantially the same as or smaller than the area of the second display region.

That is, the light emitting element does not necessarily have to be formed in the entire second display region, and may be formed in a required area according to the required screen brightness. In this respect, in the present invention, the light emitting element has an area that is substantially the same as or smaller than the area of the second display region. Therefore, the power consumption of the light emitting display element can be further reduced.

Further, the display device of the present invention is characterized in that, in the display device described above, the light emitting element is an organic electroluminescence element.

Therefore, the light modulation element and the organic electroluminescence element can be easily incorporated between the first substrate and the second substrate.

Further, by using a current-driven type organic electroluminescence element as the light emitting element,
Since the power consumption of the light emitting element is proportional to the light emitting area, the power consumption of the display device according to the present invention is lower than that when the organic electroluminescent element is used as a backlight.
The power consumption is, for example, 1/5. Therefore, it is possible to reliably reduce the power consumption.

Further, the display device of the present invention is characterized in that, in the display device described above, the light modulation element is a liquid crystal display element.

According to the above invention, when the light modulation element and the light emitting element are formed in the display area, it is possible to provide a display device excellent in visibility from outdoors to indoors while achieving downsizing and cost reduction. You can

Further, the display device of the present invention is characterized in that, in the display device described above, the light emitting element and the light modulation element are driven independently of each other.

According to the above invention, the light emitting element and the light modulation element are driven independently of each other. Therefore, the light emitting element and the light modulation element can be driven individually.
As a configuration for driving the light emitting element and the light modulation element independently of each other, for example, when each of the light emitting element and the light modulation element has a data signal line and a scanning signal line, or Although the data signal lines are provided respectively, the scanning signal lines may be shared.

The display device of the present invention is characterized in that, in the display device described above, the light emitting element and the light modulation element are driven by sharing a signal line.

According to the above invention, the light emitting element and the light modulation element are driven by sharing the signal line. Therefore, it is possible to prevent the structure of the drive circuit for the light emitting element and the light modulation element from becoming complicated, and to provide a display device excellent in visibility from outdoors to indoors while surely achieving miniaturization and cost reduction. be able to.

The display device of the present invention is the display device described above, wherein the liquid crystal layer which is the light modulation layer of the liquid crystal display element is in the horizontal alignment mode in the first display region, and
The display region is characterized by a vertical alignment mode.

As a result, when the voltage is not applied to the light modulation element, the first display area is white display, while when the voltage is applied to the light modulation element, the reflectance becomes zero and the first display area is displayed. Is displayed in black.

Therefore, according to the present invention, when the light emitting element and the light modulation element are driven at the same time, black is displayed around the second display area, which is the display area of the light emitting element, so that the light emitting element is driven to emit light. It is possible to prevent a decrease in contrast.

Further, when the characteristics of the light modulation element are set to the horizontal alignment mode, the pixel electrode for driving the liquid crystal display element is not formed in the second display region where the light emitting element displays, so that the initial alignment is performed. Maintain horizontal orientation. Therefore, in a state where the horizontal orientation is maintained, the amount of external light that enters the light emitting element increases in a place where there is a large amount of external light, such as in the open air. For example, when the light emitting element has the function of a reflector, The light reflected by the light increases.

In this respect, according to the present invention, the liquid crystal layer laminated on the light emitting element has a vertical alignment, and the liquid crystal layer in the first display region has a horizontal alignment. Therefore, when only the light emitting element emits light without driving the light modulation element,
It is possible to prevent deterioration of contrast and adverse effects on display quality due to superposition of reflected light of external light in the second display region.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] The following will describe one embodiment of the present invention with reference to FIGS. 1 and 4 to 10.

As shown in FIG. 4, the display device 1 of the present embodiment has a plurality of source bus lines 2a as data signal lines provided in the vertical direction and a plurality of scanning signal lines provided in the horizontal direction. Each of the display pixels 10 as a display area is formed in a matrix by the gate bus lines 3.

The display pixel 10 in the present embodiment is
It is divided into a reflective region 11 as a first display region having reflectivity and a transmissive region 12 as a second display region having transmissivity. That is, as shown in FIG. 1, a pixel electrode 25 made of a metal such as aluminum (Al), which constitutes a reflective liquid crystal display element 20 as a light modulation element, is formed in the reflective area 11, and The external light 4 is reflected by the pixel electrode 25.

On the other hand, as shown in the figure, a rectangular opening 25a is formed in the center of the pixel electrode 25, and this opening 25a serves as the transmission region 12. Below the opening 25 a of the pixel electrode 25, that is, behind the pixel electrode 25, an organic E as a light emitting element is provided via a transparent insulating layer 24.
An L (Electro Luminesence) light emitting element 40 is provided, and the organic EL light emitting element 40 emits the display light 5 by itself to directly display. That is, in the present embodiment, the organic EL light emitting element is not used as a backlight or front light as in the conventional case, but
Since the organic EL light emitting element 40 performs a direct display, the display device 1 according to the present embodiment includes an organic EL light emitting element 40 and a reflective liquid crystal display device including the liquid crystal display element 20. It can be said that the display device is integrated with an EL (Electro Luminesence) display device.

Here, the organic EL light emitting device 40 is
The area may be substantially the same as or smaller than the area of the transmissive region 12. That is, the organic EL light emitting element 40 does not necessarily have to be formed in all of the transmissive region 12, and may be formed in a required area according to the required screen brightness. Therefore, by making the area of the organic EL light emitting device 40 smaller than that of the transmissive region 12, it becomes possible to reduce the power consumption of the organic EL light emitting device 40. In addition, the organic EL light emitting device 40 is substantially the same as the area of the transmissive region 12 in the organic EL light emitting device 40.
Means that it may be slightly larger than the area of the transmissive region 12. That is, the organic EL light emitting device 40
This is because it is considered that the irradiation efficiency of the organic EL light emitting device 40 is not impaired if the light emitting area is slightly larger than the area of the transmissive region 12. Further, even if the organic EL light emitting element 40 is slightly larger than the area of the transmissive region 12, there is no problem because the pixel electrode 25 plays the role of a black matrix.

The display device 1 described above, as shown in FIG.
A thin film transistor element for liquid crystal (hereinafter referred to as a "TFT element for liquid crystal: Thin Film Transistor") is provided on an insulating substrate 21 as a first substrate such as a glass substrate. ) 22. As shown in FIG. 4, the liquid crystal TFT element 22 includes the gate bus lines 3 ... And the source bus lines 2.
, and functions as a switching element for applying a voltage to the pixel electrode 25 through the drain electrode 22a. In the present embodiment, the liquid crystal TFT element 22 is used as the switching element, but the switching element is not necessarily limited to this. For example, a liquid crystal MIM (Metal Insu) is used.
lator metal) element.

On the other hand, the drain electrode 22a of the liquid crystal display element 20 is, as shown in FIG.
EL thin film transistor element for driving (hereinafter,
It is called "EL TFT element". ) 42 gate electrode 42
connected to a. Further, this EL TFT element 42
The current supply line 2b is connected to the source side of the current supply line 2b, and when the EL TFT element 42 is turned on, the current supply lines 2b and E are supplied by the supply voltage Vdd described later.
A driving current flows through the drain electrode 42a of the L TFT element 42 to the organic EL layer 41 of the organic EL light emitting element 40, and the organic EL layer 41 emits light. The driving circuits for the liquid crystal display element 20 and the organic EL light emitting element 40 will be described in detail later.

Here, in order to explain the structure of the display device 1 in more detail, the description will be made below with reference to FIGS. 1 and 4 together with the description of the manufacturing method.

First, as shown in FIG. 1, a liquid crystal TFT element 22 is formed on an insulating substrate 21 such as a glass substrate.
At this time, the EL TFT element 42 is also formed at the same time.
Next, after the flattening film 23 is formed with a thickness of 2 μm, for example, using a photosensitive acrylic resin, the organic EL light emitting device 40 is formed.
The reflective anode 43 constituting the above is formed of chromium (Cr) with a thickness of 2000 Å by a sputtering method. Further, the insulating layer 44 is formed by forming silicon dioxide (SiO ₂ ) to a thickness of 2000 Å by a sputtering method and performing etching so as to have a predetermined shape.

Subsequently, an organic E as a light emitting layer is formed by a vapor deposition method.
The L layer 41 is formed. The organic EL layer 41 is formed by mask evaporation using red, green, and blue light emitting materials corresponding to the respective display pixels 10. Next, in order to efficiently inject electrons into the organic EL layer 41, an alloy (not shown) of magnesium and silver having a thickness of 100 Å is formed by a vapor deposition method, and then a cathode 45 having transparency is formed by an indium-zinc oxide by a sputtering method. (IZO) is formed to a thickness of 2000Å. Then, the transparent insulating layer 2 is formed by the sputtering method.
4, tantalum pentoxide (Ta ₂ O ₅ ) is formed to a thickness of 7,000 Å, and then a pixel electrode 25 having reflectivity for driving the liquid crystal layer 26 constituting the liquid crystal display element 20 is formed of aluminum (Al). .

On the other hand, the color filter layer 2 is formed on the insulating substrate 29 as the second transparent substrate such as the other glass substrate.
8 and indium-tin oxide (ITO: Indium Tin O
The counter electrode 27 made of xide) is sequentially formed.

Next, an unillustrated alignment film (trade name "JALS204 (manufactured by Japan Synthetic Rubber Co., Ltd.)" having a property of vertically aligning liquid crystal molecules with respect to the insulating substrate 29 is applied by spin coating and then baked. To form.

Then, the molded substrate on the side of the insulating substrate 21 is irradiated with ultraviolet light through a mask (not shown) having an opening so as to expose only the region other than the region where the organic EL light emitting element 40 is formed. On the other hand, when the molded substrate on the insulating substrate 29 side is also bonded to the insulating substrate 21,
The region other than the portion facing the organic EL light emitting element 40 is irradiated with ultraviolet light. After rubbing these two molded substrates to uniaxially align the alignment film (not shown),
Dielectric anisotropy is positive after bonding with sealing resin
A liquid crystal display device 20 is manufactured by injecting a liquid crystal material (manufactured by Merck & Co., Inc.) having n of 0.06. Further, the display device 1 is completed by sequentially adhering the retardation plate 31 and the polarizing plate 32 to the surface of the insulating substrate 29. The phase difference plate 31
The phase difference of was 1/4 with respect to the light of λ = 550 nm.

When the display device 1 manufactured in this manner is observed under the external light 4 with no voltage applied, as shown in FIG. 8 described later, the portion located above the organic EL light emitting element 40 is The black display and the portion where the organic EL light emitting element 40 is not formed are the white display. This is because the functional group that expresses the vertical alignment property of the alignment film is cleaved at the portion irradiated with ultraviolet light, so that the liquid crystal molecules are separated into the insulating substrate 21 and the insulating substrate 2.
This is because they are oriented parallel to 9.

As a result, the display mode of the liquid crystal layer 26 is a normally white mode in which white is displayed in the state where no voltage is applied, and the reflectance is gradually reduced by applying a voltage to display black.

Next, an example of a drive circuit for driving the display device 1 having the above configuration will be described.

As shown in FIG. 5, in the display device 1, the source driver 6 for sequentially sending the data line signals is connected to the source bus lines 2a ... And the gate driver 7 for selecting the display pixels 10 ... It is connected to the gate bus line 3 ... The display circuit in one display pixel 10 is composed of a liquid crystal display element 20 which is a light modulation element and an organic EL light emitting element 40 which is a light emitting element.

The liquid crystal display element 20 and the organic EL light emitting element 40 are arranged in a matrix in the display area of the display device 1, and the counter electrode 2 of the liquid crystal display element 20 is arranged.
7. The current supply line 2b of the EL TFT element 42 and the cathode 45 of the organic EL light emitting element 40 are commonly connected to each of the liquid crystal display element 20 and the organic EL light emitting element 40. That is, in this drive circuit, gates which are signal lines and scanning signal lines for driving the liquid crystal display element 20 and the organic EL light emitting element 60 in order to actively drive each display pixel 10 ... As a display area formed in a matrix. The bus lines 3 and the source bus lines 2a, which are signal lines and data signal lines, are commonly used. However, the present invention is not limited to this, and can be applied to a simple matrix.

As shown in FIG. 6, the liquid crystal TFT element 2 has a circuit configuration for one pixel in the display device 1 having the above configuration.
The two gate electrodes are connected to the gate bus line 3, and the source bus line 2a is connected to the source electrode of the liquid crystal TFT element 22. Further, the drain electrode 22a of the liquid crystal TFT element 22 is connected to the liquid crystal display element 20, the liquid crystal auxiliary capacitance 35, and the gate electrode of the EL TFT element 42. The source electrode of the EL TFT element 42 is connected to the current supply line 2b, and the drain electrode of the EL TFT element 42 is connected to the anode 43 of the organic EL light emitting element 40. In the above configuration, the organic EL light emitting device 40
Is provided on the drain side of the EL TFT element 42, but is not necessarily limited to this, and may be provided on the source side of the EL TFT element 42 as shown in FIG. 7, for example.

In the drive circuit of the display device 1 thus constructed, the liquid crystal TFT elements 22 are driven by the scanning line signals from the gate bus lines 3 ...
Change the signal of. Then, as shown in FIG. 8, when the data line signal Vs is smaller than the EL threshold voltage Vth (OLED) of the EL TFT element 42, the organic EL light emitting element 40 does not emit light and the liquid crystal display element 20 reacts. , From bright display to dark display, that is, black display. Further, the data line signal Vs is the EL threshold voltage Vth of the EL TFT element 42.
If it is larger than (OLED), the liquid crystal display element 20
Shows a dark display, but E by the data line signal Vs
The drain current of the L TFT element 42 changes, and the organic EL
A light emitting display is performed by adjusting the light emission amount of the light emitting element 40.
The amount of light emitted from the organic EL light emitting element 40 can be adjusted by adjusting the supply voltage Vdd. Further, the display device 1 of the present embodiment is not limited to this driving method, and other driving methods may be used, but the driving method shown in FIG. 8 is optimal because the driving circuit is common.

The above display operation will be described in detail with reference to FIGS. It should be noted that FIGS. 9 to 11 show the state of light when the birefringence of the liquid crystal layer 26 when the voltage is not applied is λ / 4, which is the condition where the reflectance is highest.

First, when the display device 1 is used under external light 4, when the voltage of the data line signal Vs is not applied or the drain voltage Vd of the liquid crystal TFT element 22 is equal to or lower than the liquid crystal threshold voltage Vth (LC). In this case, as shown in FIG. 9, the external light 4 passes through the polarizing plate 32 and the retardation plate 31 and then becomes circularly polarized light, and enters the liquid crystal layer 26. Next, since the liquid crystal layer 26 has a phase difference of λ / 4, when it reaches the reflective pixel electrode 25, the liquid crystal layer 26 has a phase difference of λ / 2 and is reflected as linearly polarized light. After being reflected, the external light 4 passes through a path opposite to that at the time of incidence and becomes linearly polarized light, so that it is transmitted through the polarizing plate 32 and white display is performed.

At this time, since the drain voltage Vd of the liquid crystal TFT element 22 is equal to or lower than the EL threshold voltage Vth (OLED) at which the EL TFT element 42 operates, no current is supplied to the organic EL light emitting element 40. The light is turned on.

Next, when the display device 1 is used under the external light 4, the liquid crystal display element when the drain voltage Vd of the liquid crystal TFT element 22 which is higher than the liquid crystal threshold voltage Vth (LC) is applied. The black display of 20 will be described.

As shown in FIG. 10, since the birefringence of the liquid crystal layer 26 is substantially zero, the ambient light 4 is reflected by the pixel electrode 25.
When it reaches, the state of circularly polarized light, for example, right-handed circularly polarized light, is maintained, but at the time of reflection, it becomes circularly polarized light that is the reverse of the left-handed circularly polarized light. Therefore, the reflected light of the external light 4 becomes linearly polarized light having an angle of 90 degrees orthogonal to the transmission axis of the polarizing plate 32 after passing through the retardation plate 31. Therefore, the reflected light of the external light 4 cannot pass through the polarizing plate 32, and the display becomes black.

At this time, the drain voltage Vd of the liquid crystal TFT element 22 is set to the EL value at which the EL TFT element 42 operates.
Is less than the threshold voltage Vth (OLED) for the organic E
No current is supplied to the L light emitting element 40 and the non-light emitting state is maintained.

Next, when the intensity of the external light 4 is weak, the organic E
A case where the L light emitting element 40 emits light will be described.

In this case, as shown in FIG. 11, the drain voltage Vd of the liquid crystal TFT element 22 is set to be equal to or higher than the EL threshold voltage Vth (OLED) at which the EL TFT element 42 operates. As a result, a current is supplied to the organic EL light emitting element 40 to emit light. At this time, as shown in FIG. 5, since the drain voltage Vd is sufficiently high and the liquid crystal layer 26 displays black, it does not affect the light emission of the organic EL light emitting element 40.

Here, in the present embodiment, the anode 43 constituting the organic EL light emitting device 40 is made of a reflective metal,
It always reflects light regardless of the display signal. For this reason, when an organic EL display is mounted on a product such as a mobile phone that is often used outdoors, it is necessary to attach a circularly polarizing plate to the observer side, but in this embodiment, as shown in FIG. In addition, the polarizing plate 32 necessary for displaying the liquid crystal layer 26 and the retardation plate 31 having a phase difference of λ / 4 wavelength are used for the external light 4
It has a function of making the reflection of the light almost zero. In addition, organic E
Although the liquid crystal layer 26 exists between the L light emitting element 40 and the polarizing plate 32, the liquid crystal layer 26 in this portion has an electrode such as the counter electrode 27 formed only on the insulating substrate 29 side. Therefore, the liquid crystal layer 26 is always in the OFF state regardless of the applied voltage, and does not adversely affect the suppression of the reflection of the external light 4.

In this embodiment, since the transparent insulating layer 24 is formed so as to cover the entire surface of the organic EL light emitting element 40, the liquid crystal of the liquid crystal layer 26 may penetrate into the organic EL light emitting element 40. Since there is no interference with the liquid crystal display element 20, it is possible to improve the reliability of the organic EL light emitting element 40.

As described above, in the display device 1 of the present embodiment, the liquid crystal display element 20 is arranged in each display pixel 10 ...
A reflective region 11 formed of a non-emissive display element that reflects light to perform display and a transmissive region 12 formed of a light-emitting display element that is directly modulated by the organic EL light emitting device 40 to display are provided.

Therefore, since the organic EL light emitting element 40 emits light itself toward the display surface side to directly display, the organic EL light emitting element 40 is not used as a back light or a front light as in the conventional case. . As a result, the utilization efficiency of light of the organic EL light emitting element 40 can be improved, and the thickness of the display device can be reduced. That is, since the thickness of the backlight is normally about 3 to 6 mm, the merit of reducing the thickness by eliminating the need for the backlight is very large. Further, the need for a backlight means that a polarizing plate, a retardation plate, and a glass substrate, which are conventionally installed between the back panel of the liquid crystal panel and the backlight, are also unnecessary. Therefore, the thickness of the display device can be further reduced by eliminating the need for these polarizing plate, retardation plate and glass substrate.

Further, the merit that the backlight, the polarizing plate and the retardation film on the back side are not necessary is not only the reduction in the thickness of the entire display device. That is, the reduction in the number of members can reduce not only the material cost but also the number of assembling steps and the cost required for inspecting each member, so that the manufacturing cost of the entire display device can be reduced.

Further, in the display device 1 of the pixel division type as in this embodiment, it is possible to design the ratio of the reflection area 11 and the transmission area 12 to an arbitrary degree to some extent. Therefore, for example, when it is assumed that the device is used for a mobile device such as a mobile phone or a personal digital assistant (PDA), the reflection area 11
It is common to increase the ratio of. For example, when 80% of the pixel area of the display pixels 10 is the reflective area 11, the transmissive area 12 is 20%, so that the organic E
The light emitting area of the L light emitting element 40 is at most 1/5 of the pixel area of the display pixel 10. This means that it is possible to reduce power consumption.

Further, in this embodiment, the insulating substrate 21 and the insulating substrate 29 facing each other are provided, and the organic E
Both the L light emitting element 40 and the liquid crystal display element 20 are provided between the insulating substrate 21 and the insulating substrate 29. In the transmissive region 12, the organic EL light emitting device 40 and the liquid crystal layer 26 of the liquid crystal display device 20 are sequentially stacked on the insulating substrate 21. Therefore, since the liquid crystal display element 20 and the organic EL light emitting element 40 are both housed between the insulating substrate 21 and the insulating substrate 29, the thickness of the display device 1 can be surely reduced. Further, even if the liquid crystal layer 26 is laminated on the surface side of the organic EL light emitting element 40, the organic EL light emitting element 40 is provided between the insulating substrate 21 and the insulating substrate 29, so that the organic EL light emitting element is provided. All 40 display lights are emitted to the transmissive region 12. Therefore, the utilization efficiency of light becomes very high.

Therefore, the display device 1 is excellent in visibility from outdoors to indoors while achieving downsizing and cost reduction.
Can be provided.

By the way, the organic EL light-emitting device 40 does not necessarily have to be formed in all of the transmissive region 12, but may be formed in a required area according to the required screen brightness.
In this respect, in the display device 1 of the present embodiment, the organic EL light emitting element 40 has an area that is substantially the same as or smaller than the area of the transmissive region 12. Therefore, the power consumption of the organic EL light emitting device 40 can be further reduced.

In the display device 1 of this embodiment, the light emitting element is the organic EL light emitting element 40. Therefore, the liquid crystal display element 20 and the organic EL light emitting element 40 can be easily formed.
Can be incorporated between the pair of insulating substrates 21 and 29.

Further, as a light emitting element, a current drive type organic E
By using the L light emitting element 40, the power consumption of the light emitting element is proportional to the light emitting area. Therefore, the power consumption of the display device 1 according to the present embodiment is lower than that when the organic EL light emitting element 40 is used as a backlight. , The power consumption is 1/5. Therefore, it is possible to reliably reduce the power consumption.

Further, in the display device 1 of the present embodiment, the light modulation element is the liquid crystal display element 20. Therefore, the liquid crystal display element 20 and the organic EL light emitting element 40 can be easily integrated into one.
When formed in a pixel, light is made incident on the opening 25a with higher irradiation efficiency, so that it is possible to provide a display device 1 having excellent visibility from outdoors to indoors while achieving size reduction and cost reduction. it can.

Further, in the display device 1 of the present embodiment, the organic EL light emitting element 40 and the liquid crystal display element 20 are driven by sharing the source bus lines 2a ... And the gate bus lines 3 ... Therefore, it is possible to prevent the configuration of the drive circuit for the organic EL light emitting element 40 and the liquid crystal display element 20 from becoming complicated,
It is possible to reliably provide the display device 1 capable of reducing the thickness of the display device 1 and the cost of members.

By the way, in the present embodiment, when the organic EL light emitting element 40 emits light, for example, when white display is performed, when the liquid crystal display element 20 performs white display,
The contrast of one display pixel 10 decreases.

Therefore, in the present embodiment, the liquid crystal layer 26 of the liquid crystal display element 20 has the horizontal alignment mode in the reflective region 11 and the vertical alignment mode in the transmissive region 12. Therefore, in the state where no voltage is applied to the liquid crystal display element 20, the reflective area 11 displays white, while when a voltage is applied to the liquid crystal display element 20, the reflectance becomes zero and the reflective area 11 displays black. Become.

Therefore, in the present embodiment, the organic EL
Since black is displayed around the transmissive region 12 which is the display region of the light emitting element 40, it is possible to prevent a decrease in contrast caused by driving the organic EL light emitting element 40 to emit light.

In addition, in the liquid crystal layer 26 of the liquid crystal display element 20, the transmissive region 12 where the organic EL light emitting element 40 performs display.
In the case of horizontal alignment, since the pixel electrode 25 for driving the liquid crystal display element 20 is not formed, the parallel alignment of the initial alignment is maintained. Therefore, particularly when the display device 1 is used in a place where there is a large amount of outside light 4, such as outdoors, in the transmissive region 12 that maintains the horizontal alignment, the reflected light due to the outside light 4 increases. That is, the external light 4 is transmitted through the liquid crystal display element 20 and further reflected by the organic EL light emitting element 40.

In this respect, in the present embodiment, the liquid crystal layer 26 laminated on the organic EL light emitting device 40 has a vertical alignment, and the liquid crystal layer 26 in the reflective region 11 has a horizontal alignment. Therefore, when only the organic EL light emitting element 40 emits light without driving the liquid crystal display element 20, it is possible to prevent the deterioration of the contrast and the bad influence on the display quality due to the superposition of the reflected light of the external light 4 in the transmissive region 12. be able to.

Further, in this embodiment, the insulating substrate 29 is used.
Although the color filter layer 28 formed above is formed in all the portions facing the reflective area 11 and the transmissive area 12, the present invention is not limited to this, and for example, the portion facing the transmissive area 12, that is, the organic EL light emitting element 40 is opposed. The color filter layer 28 may not be formed in the area to be filled. This allows
The light emitted from the organic EL layer 41 is emitted from the color filter layer 2
Since it is not absorbed by 8, the brighter display becomes possible. In addition, since the color purity of the organic EL layer 41 is usually higher than that of the color filter layer 28, more vivid colors can be displayed.

In this embodiment, the reflection type liquid crystal display element 20 is used as the light modulation element, but the present invention is not limited to this. For example, a mirror or the like is used to change the light reflection amount for display. A display element that can be used may be used. Further, it is possible to use an electrophoretic display, a twist ball display, a reflective display using a fine prism film, a reflective light modulator such as a digital mirror device.

Further, although the organic EL light emitting element 40 is used as the light emitting element in the present embodiment, the present invention is not limited to this. For example, an inorganic EL light emitting element, an LED (Light Em
It is applicable as long as it is an element such as an itting diode) whose emission luminance is variable. It is also possible to use a light emitting element such as a field emission display (FED) or a plasma display.

[Second Embodiment] The following will describe another embodiment of the present invention in reference to FIGS. 12 to 14. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment will be designated by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, the case where the liquid crystal display element 20 and the organic EL light emitting element 40 are simultaneously driven will be described. Note that the driving here does not mean that a voltage is simply applied to the liquid crystal display element 20 or that a current is simply flowing through the organic EL light emitting element 40, but is not dependent on the voltage or the information displayed by the current. Is controlled to change the reflected light intensity or the light emission intensity of the light emitting element and display is performed.

In the present embodiment, in manufacturing the display device 1, an alignment film (not shown) having a property of vertically aligning the liquid crystal molecules shown in FIG. (Manufactured by Rubber Co., Ltd.) ”), and then subjected to orientation treatment by rubbing, and thereafter, two moldings, a molding substrate on the insulating substrate 29 side and a molding substrate on the insulating substrate 21 side, via a seal resin (not shown). The substrates are bonded together, and a liquid crystal material having a negative dielectric anisotropy (product name “MLC6608 (manufactured by Merck Ltd.)”) is injected as the liquid crystal layer 26 to form the liquid crystal display element 20. Further, the display device 1 is completed by sequentially adhering the retardation plate 31 and the polarizing plate 32 to the surface of the insulating substrate 29. Also in this embodiment, the retardation of the retardation plate 31 is λ = 550 nm.
The light used was 1/4 of the light of.

In this embodiment, as the drive circuit, a drive circuit different from that of the first embodiment is used. That is, in the present embodiment, the liquid crystal display element 20 and the organic EL light emitting element 40 are driven independently of each other.

A specific display operation of the display device 1 having the above configuration will be described with reference to FIGS.

First, as shown in FIG. 12, in the display mode of the liquid crystal layer 26, as described above, the liquid crystal layer 26 made of a liquid crystal material having a negative dielectric anisotropy and a vertical alignment film (not shown) are used. Since it is used, black is displayed in the state where no voltage is applied, while as shown in FIG. 13, a normally black mode in which reflectance is gradually increased by voltage application and white display is performed.

That is, when the display device 1 is used under the external light 4, when no voltage is applied or the drain voltage Vd is equal to or lower than the common threshold voltage Vth, the external light 4 is reflected by the polarizing plate 32 and the polarizing plate 32 as shown in FIG. After passing through the phase difference plate 31, it becomes circularly polarized light and enters the liquid crystal layer 26. When the drain voltage Vd equal to or lower than the common threshold voltage Vth is applied to the liquid crystal layer 26 by the liquid crystal TFT element 22, the birefringence of the liquid crystal layer 26 is 0, and therefore, when the reflective pixel electrode 25 is reached, for example, The circularly polarized light of the right circularly polarized light is maintained, but when the light is reflected by the pixel electrode 25, for example, the circularly polarized light is the reverse of the left circularly polarized light. Therefore, the reflected light becomes linearly polarized light having an angle of 90 degrees orthogonal to the transmission axis of the polarizing plate 32 after passing through the retardation plate 31. As a result, the reflected light of the external light 4 cannot pass through the polarizing plate 32 and the display becomes black. Therefore, as shown in FIG. 14A, the brightness of the liquid crystal display element 20 becomes substantially zero. At this time, as shown in FIG. 14B, the organic EL light emitting element 40 also has the common threshold voltage Vth.
Since it is the following, it is in the OFF state, and the organic EL layer 41 is
However, no current is supplied and the device is in a non-light emitting state.

Next, the case where white is displayed by applying a voltage will be described with reference to FIG. In the figure, the state of light in which the birefringence of the liquid crystal layer 26 is λ / 4, which is the condition under which the reflectance is highest, is described.

As shown in FIG. 13, when a drain voltage Vd that is equal to or higher than the common threshold voltage Vth is applied to the liquid crystal layer 26, the liquid crystal layer 26 has a birefringence and cannot maintain a circularly polarized state. Therefore, the reflected light of the external light 4 from the reflective pixel electrode 25 passes through the polarizing plate 32, and
As shown in FIG. 4A, the brightness display of the liquid crystal display element 20 is white.

At this time, as shown in FIG.
Since the FT element 42 is also in the ON state, the current supplied from the current supply line 2b causes the organic EL light emitting element 40 to be in the light emitting state as shown in FIG. 14 (b).

Here, as shown in FIG.
The anode 43 forming the light emitting element 40 is made of a reflective metal and always reflects light regardless of a display signal. Therefore, when the organic EL display is mounted on a product that is often used outdoors such as a mobile phone, it is necessary to attach the circularly polarizing plate to the observer side. However, in the present embodiment, the display of the liquid crystal layer 26 is displayed. The polarizing plate 32 and the retardation plate 31 having a phase difference of λ / 4 wavelength, which are necessary for the above, have a function of making such reflection of the external light 4 almost zero.

In addition, the organic EL light emitting device 40 and the polarizing plate 32
There is a liquid crystal layer 26 between the transparent region 12 and
In the liquid crystal layer 26, the electrode is formed only on the side of the insulating substrate 29 like the counter electrode 27. For this reason, as shown in FIGS. 12 and 13, the liquid crystal layer 26 is always in the OFF state regardless of the applied voltage and maintains the vertical alignment property, so that the reflection of the external light 4 is not adversely affected.

In this embodiment, the example in which the liquid crystal layer 26 and the organic EL light emitting element 40 are simultaneously driven has been described.
When the external light 4 is strong, the current supply to the organic EL light emitting element 40 is cut off to display only the liquid crystal layer 26 and reduce the power consumption.

Also in the present embodiment, as in the case of the first embodiment, the transparent insulating layer 24 is formed so as to cover the entire surface of the organic EL light emitting element 40, so that the liquid crystal layer 2 is formed.
The liquid crystal of No. 6 does not penetrate into the organic EL light emitting element 40 and does not interfere with the liquid crystal display element 20.
The reliability of the L light emitting element 40 can be improved.

As described above, in the display device 1 of the present embodiment, the organic EL light emitting element 40 and the liquid crystal display element 20 are driven independently of each other. Therefore, the organic EL light emitting device 40 and the liquid crystal display device 20 can be driven individually. The organic EL light emitting element 40 and the liquid crystal display element 2
As a configuration for driving 0 and 0 independently of each other, for example, each of the organic EL light emitting element 40 and the liquid crystal display element 20 has a source bus line 2a ... And a gate bus line 3 ..., or , Source bus line 2a ...
May be provided respectively, but the gate bus lines 3 ... May be shared.

Further, in the display device 1 of the present embodiment, the liquid crystal display element 20 is normally black.
Therefore, the liquid crystal display element 20 and the organic EL light emitting element 40
When the liquid crystal display element 20 is not driven and only the organic EL light-emitting element 40 is driven when driving and, the light is reflected around the transmissive area 12 which is the display area of the organic EL light-emitting element 40. Not displayed in black.

Therefore, it is possible to prevent a reduction in contrast when only the organic EL light emitting element 40 is driven to emit light.

The present embodiment has the same structure and function as those of the first embodiment except that the liquid crystal display element 20 is normally black.

[0115]

As described above, in the display device of the present invention, the light-emitting element and the first display area which is the non-light-emitting display element in which the light modulation element reflects the external light to perform display are provided in the display area. A second display area including a light emitting display element that directly modulates and displays is provided side by side, and a first substrate and a second substrate that face each other are provided, and both the light modulation element and the light emitting element are the above. It is provided between the first substrate and the second substrate, and in the second display region, the light emitting element and the light modulation layer of the light modulation element are sequentially laminated on the first substrate. is there.

Therefore, the light emitting element emits light itself toward the display surface side to directly display, and thus the light emitting element is not used as a backlight or a front light as in the conventional case. As a result, the light utilization efficiency of the light emitting element can be improved, and the thickness of the display device can be reduced.

Further, since the backlight, the polarizing plate, and the retardation plate are unnecessary, the number of members is reduced. For this reason,
Not only the material cost but also the assembly man-hour and the cost required for inspecting each member can be reduced, so that the manufacturing cost of the entire display device can be reduced.

In the pixel division type display device as in the present invention, the ratio of the first display region to the second display region can be designed to some extent. For this reason, for example, when 80% of the pixel area of the display pixel is the reflective area, the second display area, which is the light emitting area, is 20%, so that the light emitting area of the light emitting element is 5 at most of the pixel area. One-third.

Therefore, there is an effect that it is possible to provide a display device excellent in visibility from outdoors to indoors while achieving downsizing and cost reduction.

Further, in the display device of the present invention, in the display device described above, the light emitting element has an area which is substantially the same as or smaller than the area of the second display region.

Therefore, the power consumption of the light emitting element can be further reduced.

The display device of the present invention is the display device described above, wherein the light emitting element is an organic electroluminescent element.

Therefore, the light modulation element and the organic electroluminescence element can be easily incorporated between the first substrate and the second substrate.

By using a current drive type organic electroluminescence element as the light emitting element,
Since the power consumption of the light emitting element is proportional to the light emitting area, the power consumption of the display device according to the present invention is lower than that when the organic electroluminescent element is used as a backlight.
The power consumption is, for example, 1/5. Therefore, it is possible to reliably reduce the power consumption.

Further, in the display device of the present invention, in the display device described above, the light modulation element is a liquid crystal display element.

Therefore, when the light modulating element and the light emitting element are formed in the display area, it is possible to easily provide a display device excellent in visibility from outdoors to indoors while achieving downsizing and cost reduction. It has the effect of being able to.

Further, in the display device of the present invention, in the display device described above, the light emitting element and the light modulation element are driven independently of each other.

Therefore, it is possible to individually drive the light emitting element and the light modulation element.

The display device of the present invention is the display device described above, wherein the light emitting element and the light modulation element are driven by sharing a signal line.

Therefore, it is possible to provide a display device which can prevent the structure of the drive circuit for the light emitting element and the light modulation element from becoming complicated, and can surely reduce the thickness of the display device and the member cost. There is an effect that can be.

Further, in the display device of the present invention, in the display device described above, the liquid crystal layer which is the light modulation layer of the liquid crystal display element is in the horizontal alignment mode in the first display region, and
The display region is in the vertical alignment mode.

Therefore, in the state where no voltage is applied to the light modulation element, the first display area is white display, while when a voltage is applied to the light modulation element, the reflectance becomes zero and the first display area is displayed. Is displayed in black.

Therefore, according to the present invention, when the light emitting element and the light modulation element are driven at the same time, black is displayed around the second display area, which is the display area of the light emitting element, so that the light emitting element is driven to emit light. It is possible to prevent a decrease in contrast.

The liquid crystal layer laminated on the light emitting element has a vertical alignment, and the liquid crystal layer in the first display region has a horizontal alignment. Therefore, when only the light emitting element emits light without driving the light modulation element, it is possible to prevent deterioration of contrast and adverse effects on display quality due to superposition of reflected light of external light in the second display region. Produce an effect.

[Brief description of drawings]

FIG. 1 illustrates an embodiment of a display device according to the present invention, and shows one pixel in the display device, which is indicated by A in FIG.
FIG.

FIG. 2 is a graph showing a concept of the present invention and showing a relationship between a display environment and power consumption.

FIG. 3 is a graph showing a concept of the present invention and showing a relationship between a display environment and brightness.

FIG. 4 is a plan view showing one pixel in the display device.

FIG. 5 is an overall configuration diagram showing the display device.

FIG. 6 is a drive circuit diagram showing one pixel of the display device.

FIG. 7 is another drive circuit diagram showing one pixel of the display device.

FIG. 8 is a signal waveform diagram when the display device is driven.

FIG. 9 shows a case where the display device is in a normally white mode and the drain voltage Vd is the threshold voltage V for liquid crystal.
It is explanatory drawing which shows the display state of a liquid crystal display element and an organic EL light emitting element when it is smaller than th (LC).

FIG. 10 shows a case in which the drain voltage Vd is higher than the liquid crystal threshold voltage Vth (LC) and the EL threshold voltage Vth when the display device is in the normally white mode.
It is explanatory drawing which shows the display state of a liquid crystal display element and an organic EL light emitting element when it is smaller than (OLED).

FIG. 11 is a diagram illustrating a case where the display device is in a normally white mode, in which a drain voltage Vd is higher than a liquid crystal threshold voltage Vth (LC) and an EL threshold voltage Vth.
It is explanatory drawing which shows the display state of a liquid crystal display element and an organic EL light emitting element when it is larger than (OLED).

FIG. 12 shows a case where the drain voltage Vd is the common threshold voltage V when the display device is in a normally black mode.
It is explanatory drawing which shows the display state of a liquid crystal display element and an organic EL light emitting element when it is smaller than th.

FIG. 13 shows a case where the drain voltage Vd is a common threshold voltage V when the display device is in a normally black mode.
It is explanatory drawing which shows the display state of a liquid crystal display element and an organic EL light emitting element when it is larger than th.

FIG. 14A is an explanatory diagram showing a luminance state of a liquid crystal display element when the display device is in a normally black mode, and FIG. 14B is an organic EL light emission when the display device is in a normally black mode. It is explanatory drawing which shows the brightness | luminance state of an element.

FIG. 15 is a cross-sectional view showing a conventional display device.

[Explanation of symbols]

1 Display Device 2a Source Bus Line 2b Current Supply Line 3 Gate Bus Line 4 External Light 5 Display Light 6 Source Driver 7 Gate Driver 10 Display Pixel (Display Area) 11 Reflection Area (First Display Area) 12 Transmission Area (Second Display) Area 20 Liquid crystal display element (light modulation element) 21 Insulating substrate (first substrate) 22 Liquid crystal TFT element 22a Drain electrode 24 Transparent insulating layer 25 Pixel electrode 25a Opening 26 Liquid crystal layer 27 Counter electrode 29 Insulating substrate (first) 2 substrate) 31 retardation plate 32 polarizing plate 40 organic EL light emitting element (light emitting element, organic electroluminescence element) 42 EL TFT element Vdd supply voltage Vth shared threshold voltage Vth (LC) liquid crystal threshold voltage Vth (OLED) for EL Threshold voltage Vs Data line signal

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09F 9/30 338 G09F 9/30 338 5C094 365 365Z 9/35 9/35 9/46 9/46 Z G09G 3/20 611 G09G 3/20 611A 624 624B 680 680D 680H 3/30 3/30 J 3/36 3/36 (72) Inventor Akito Jinda 22-22 Nagaikecho, Abeno-ku, Osaka, Osaka Prefecture F term (reference) 2H089 HA08 HA21 HA27 HA29 HA33 KA20 TA02 TA04 TA07 TA18 2H090 LA01 LA04 LA17 MA01 MA02 MA15 2H092 GA11 GA24 PA02 PA13 5C006 BB15 BB29 BC06 BC08 EB05 FA47 FA51 5C080 AA06 AA10 BB05 CC07 JJ060626 DD25 DD06 DD05 DD06 DD05 DD08 DD25 DD06 CC05 DD25 DD08 DD25 DD05 DD08 DD25 DD06 DD07 DD25 AA06 AA15 AA22 AA43 AA51 AA56 BA03 BA27 BA43 CA19 CA20 DA02 DA03 DB01 DB04 EA04 EA05 EA06 EB02 EB04 ED11 ED14 FA01 FA02 FB0 1 FB20 GA10 HA10

Claims (7)

[Claims] 1. A first display area comprising a non-light emitting display element in which a light modulation element reflects external light for display in the display area, and a light emitting display element in which the light emitting element directly modulates for display. Two display areas are provided side by side, and a first substrate and a second substrate facing each other are provided, and the light modulation element and the light emitting element are both the first substrate and the second substrate.
A display device, which is provided between a substrate and a second display region, wherein the light emitting element and a light modulation layer of a light modulation element are sequentially laminated on the first substrate. 2. The display device according to claim 1, wherein the light emitting element has an area which is substantially the same as or smaller than the area of the second display region. 3. The display device according to claim 1, wherein the light emitting element comprises an organic electroluminescence element. 4. The display device according to claim 1, wherein the light modulation element is a liquid crystal display element. 5. The display device according to claim 1, wherein the light emitting element and the light modulation element are driven independently of each other. 6. The display device according to claim 1, wherein the light emitting element and the light modulation element are driven by sharing a signal line. 7. A liquid crystal layer which is a light modulation layer of a liquid crystal display element,
7. The display device according to claim 6, wherein the first display region has a horizontal alignment mode and the second display region has a vertical alignment mode.