JP2018022038A - Display device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device with low power consumption.SOLUTION: A display device has a first cabinet, a second cabinet, a first display area, and a second display area. The first display area has a region overlapping the first cabinet, the second display area has a region overlapping the second cabinet, the first cabinet is connected to the second cabinet through a hinge part, the first display area and the second display area each have a first display element, and the second display area further has a second display element. The first display element is configured to reflect visible light, and the second display element is configured to emit visible light.SELECTED DRAWING: Figure 1

Description

The present invention relates to an object, a method, or a manufacturing method. Or this invention relates to a process, a machine, a manufacture, or a composition (composition of matter). In particular, one embodiment of the present invention relates to a semiconductor device, a light-emitting device, a display device, an electronic device, a lighting device, a driving method thereof, or a manufacturing method thereof. In particular, the present invention relates to a display device (display panel) capable of displaying on a curved surface. Alternatively, the present invention relates to an electronic device, a light-emitting device, a lighting device, or a manufacturing method thereof including a display device capable of displaying on a curved surface.

Note that in this specification and the like, a semiconductor device refers to any device that can function by utilizing semiconductor characteristics. A transistor, a semiconductor circuit, an arithmetic device, a memory device, or the like is one embodiment of a semiconductor device. In addition, the imaging light emitting device, the display device, the electronic device, the lighting device, and the electronic device may include a semiconductor device.

Active matrix liquid crystal display devices are roughly classified into two types, a transmission type and a reflection type.

The transmissive liquid crystal display device uses a backlight such as a cold cathode fluorescent lamp or an LED (Light Emitting Diode), and the light from the backlight transmits the liquid crystal by utilizing the optical modulation action of the liquid crystal. A state that is output to the outside and a state that is not output are selected, bright and dark display is performed, and further, they are combined to perform image display.

In addition, the reflective liquid crystal display device utilizes the optical modulation action of the liquid crystal, and the external light, that is, the incident light is reflected by the pixel electrode and output to the outside of the device, and the incident light is not output to the outside of the device. An image is displayed by selecting a state, displaying bright and dark, and combining them. The reflective liquid crystal display device has an advantage of low power consumption because it does not use a backlight as compared with the transmissive liquid crystal display device.

Patent Document 1 discloses a flexible active matrix light-emitting device including a transistor and an organic EL element on a film substrate.

JP 2003-174153 A

In an electronic device having a display device, the power consumption of the display device accounts for a large proportion of the power consumption of the entire electronic device.

In addition, portable electronic devices are desired to have a display device capable of highly recognizable display both indoors and outdoors.

An object of one embodiment of the present invention is to provide a display device with low power consumption. Another object is to provide a highly recognizable display device. Another object is to provide a novel display device. Another object is to provide an electronic device including the display device. Another object is to provide a new electronic device.

Note that the description of these problems does not disturb the existence of other problems. In one embodiment of the present invention, it is not necessary to solve all of these problems. Problems other than those described above are naturally clarified from the description of the specification and the like, and problems other than the above can be extracted from the description of the specification and the like.

One embodiment of the present invention includes a display device having a function of emitting visible light, a display device having a function of reflecting visible light, a display device having a function of emitting visible light, and a function of reflecting visible light, and any of the above The present invention relates to an electronic device having a display device.

One embodiment of the present invention is a display device including a first housing, a second housing, a first display region, and a second display region, and the first display region is the first display region. The second display area has an area overlapping with the second casing, and the first casing is connected to the second casing through the hinge portion. The first display area and the second display area each have a first display element, the second display area further has a second display element, and the first display element emits visible light. The second display element has a function of reflecting, and the second display element is a display device having a function of emitting visible light.

Another embodiment of the present invention is a display device including a first housing, a second housing, a first display region, a second display region, and a sensor. The display area has an area overlapping with the first casing, the second display area has an area overlapping with the second casing, and the first casing is connected to the second casing via the hinge portion. The sensor has a function of outputting the first signal, the first display area and the second display area each have a first display element and a second display element, The first display element has a function of reflecting visible light, the second display element has a function of emitting visible light, and when the sensor outputs a first signal, the first display area or the second display element One of the display areas is a display device that performs display on the first display element.

The sensor can output a first signal when an angle formed between the first housing and the second housing is a first angle or a second angle.

The first display panel is provided in the first housing, the second display panel is provided in the second housing, the first display panel is used as the first display area, and the second display panel is used as the second display panel. It can be a display area.

Alternatively, the first housing and the second housing have the first region and the second region, and a flexible display panel is provided, and the first region of the flexible display panel is provided. May be the first display area, and the second area of the flexible display panel may be the second display area.

Another embodiment of the present invention is a display device including a housing, a first display region, a second display region, and a sensor, the housing having flexibility, The display area and the second display area are provided in the housing, the sensor has a function of outputting a first signal, and each of the first display area and the second display area is a first display element. And the second display element, the first display element has a function of reflecting visible light, the second display element has a function of emitting visible light, and the sensor outputs the first signal. In some cases, one of the first display area and the second display area is a display device that performs display on the first display element.

The sensor can output the first signal when the angle formed by the first side of the housing is the first angle or the second angle.

The housing can be provided with a first display panel and a second display panel, the first display panel can be a first display area, and the second display panel can be a second display area.

Alternatively, a flexible display panel having a first region and a second region is provided in the housing, and the first region of the flexible display panel is used as the first display region. The second area of the display panel having flexibility can be used as the second display area.

The first display element is preferably a reflective liquid crystal element. The second display element is preferably a light emitting element.

The first display region and the second display region preferably include a transistor including a metal oxide in a semiconductor layer in which a channel is formed.

Another embodiment of the present invention is an electronic device that includes the above display device and includes a touch sensor at a position overlapping with at least one of the first display region and the second display region.

In this specification, a module in which a connector, for example, an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) is attached to a display device (display panel), a module in which a printed wiring board is provided at the end of TCP, Alternatively, a module in which an IC (Integrated Circuit) is directly mounted on a substrate over which a display element is formed by a COG (Chip On Glass) method may include a display device.

By using one embodiment of the present invention, a display device with low power consumption can be provided. Alternatively, a highly recognizable display device can be provided. Alternatively, a novel display device can be provided. Alternatively, an electronic device including the display device can be provided. Alternatively, a novel electronic device can be provided.

Note that the description of these effects does not disturb the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. It should be noted that the effects other than these are naturally obvious from the description of the specification, drawings, claims, etc., and it is possible to extract the other effects from the descriptions of the specification, drawings, claims, etc. It is.

FIG. 6 illustrates a structure of an electronic device. FIG. 6 illustrates a structure of an electronic device. FIG. 6 illustrates a structure of an electronic device. FIG. 6 illustrates a structure of an electronic device. 8A and 8B illustrate examples of usage states of electronic devices. The figure explaining a pixel unit. The figure explaining a pixel unit. 4A and 4B each illustrate a circuit of a display device and a top view of a pixel. FIG. 6 illustrates a circuit of a display device. 4A and 4B each illustrate a circuit of a display device and a top view of a pixel. FIG. 6 illustrates a structure of a display device. FIG. 6 illustrates a structure of a display device.

Embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

Note that in structures of the invention described below, the same portions or portions having similar functions are denoted by the same reference numerals in different drawings, and description thereof is not repeated. In addition, in the case where the same function is indicated, the hatch pattern is the same, and there is a case where no reference numeral is given.

Note that in each drawing described in this specification, the size, the layer thickness, or the region of each component is exaggerated for simplicity in some cases. Therefore, it is not necessarily limited to the scale.

In the present specification and the like, ordinal numbers such as “first” and “second” are used for avoiding confusion between components, and are not limited numerically.

(Embodiment 1)
In this embodiment, a display device and an electronic device of one embodiment of the present invention will be described with reference to drawings.

The display device of one embodiment of the present invention includes a first display region and a second display region. Each of the first display area and the second display area has a first display element, the second display area further has a second display element, and the first display element reflects visible light. The second display element has a function of emitting visible light.

The first display element can operate with low power consumption, and the second display element can perform display with high visibility. That is, display can be performed using different display elements in the first display region and the second display region in accordance with the application, and a display device with high visibility and low power consumption can be provided.

[Example of electronic equipment]
FIG. 1 illustrates an electronic device including the display device of one embodiment of the present invention.

The electronic device 10 shown in FIG. 1 can be used as a portable terminal or a notebook computer, and includes a housing 11a, a housing 11b, a display area 12a, and a display area 12b. One or both of the display area 12a and the display area 12b includes a touch sensor as an input unit.

The display area 12a is provided in the housing 11a, and the display area 12b is provided in the housing 11b. Moreover, the housing | casing 11a is connected with the housing | casing 11b via the hinge part 13, and the angle which the housing | casing 11a and the housing | casing 11b comprise can be changed by using the hinge part 13 as a fulcrum.

The display area 12a and the display area 12b each have a first display element. One of the display region 12a and the display region 12b further includes a second display element.

That is, one of the display area 12a and the display area 12b can perform display with the first display element, the second display element, or the first display element and the second display element. The other of the display area 12a and the display area 12b can perform display with the first display element.

Specifically, the display area 12a is a display area of the first display panel provided in the casing 11a, and the display area 12b is a display area of the second display panel provided in the casing 11b.

Note that in this embodiment, a structure in which the first display element is provided in the display region 12a and the first display element and the second display element are provided in the display region 12b is described. A configuration in which the first display element and the second display element are provided in both the configuration and the display regions 12a and 12b may be employed. In addition, at least the display area 12a is configured to include a touch sensor, but the touch sensors may be provided to both the display areas 12a and 12b.

Although details will be described later, for example, a reflective liquid crystal element can be used as the first display element. As the second display element, for example, a light emitting element can be used. A reflective liquid crystal element can operate with low power consumption, and a light-emitting element can perform display with high visibility.

In an electronic device having two display areas, the role of each display area is often different in actual use. For example, when one display area is used as a main screen and the other display area is used as a secondary screen, high visibility is not necessarily required for both. Therefore, it is preferable to use a display area capable of displaying with high visibility as the main screen, and use a display area capable of displaying with low power consumption even as a display with relatively poor visibility as the secondary screen. By performing such display, power consumption can be reduced without any problem in actual use.

FIG. 2A illustrates an example in which the angle formed by the first surface of the housing 11a and the first surface of the housing 11b is an obtuse angle and the display regions 12a and 12b are vertically oriented. 2A includes a terminal for reading an electronic book, use as a textbook, and the like.

In a book, two pages are in the field of view due to the structure spread, but when actually reading a character or looking at a figure or photograph, one page is intensively viewed. Therefore, in the usage example of FIG. 2A, the display area 12b capable of displaying with high visibility may be used as the main screen.

At this time, since the display of the display area 12a serving as the secondary screen is often the next page or an image that is temporarily referred to, the problem hardly occurs even if the visibility is relatively poor. . In addition, when it is desired to check the characters and images displayed in the display area 12a with high visibility, an operation for displaying them in the display area 12b may be performed.

FIG. 2B illustrates an example in which the angle formed by the first surface of the housing 11a and the first surface of the housing 11b is an obtuse angle and the display regions 12a and 12b are used in a landscape orientation. As an example of use in FIG. 2B, use as a notebook computer can be cited.

Keyboards and mice are known and widely used as input devices to computers. The input operation function using a mouse or the like can be omitted if the display area 12b has a touch sensor. Moreover, if the display area 12a has a touch sensor, a character input etc. can be performed by touching the key image displayed on the display area 12a.

For example, as shown in FIG. 2B, a keyboard image can be displayed in the display area 12a, and an input operation to the computer can be performed by touching the key image. At this time, the display area 12b is used as a main screen, and the display area 12a is used as a sub-screen. Keyboard input may be performed by blind touch, and problems are unlikely to occur even if the visibility of the display area 12a is low.

Moreover, since the angle which the housing | casing 11a and the housing | casing 11b comprise can be changed by using the hinge part 13 as a fulcrum, it can be used in various other forms. FIG. 3A shows an enlarged view of an example of the hinge portion 13. The hinge portion 13 includes a shaft 13a, a shaft 13b, a bearing 13c, and a jig 13d. Both ends of the shaft 13a are fixed to the housing 11a, and both ends of the shaft 13b are fixed to the housing 11b. Further, since the shaft 13a and the shaft 13b are fixed to the bearing 13c fixed to the jig 13d, the shaft 13a and the shaft 13b can rotate. Therefore, the angle formed by the housing 11a and the housing 11b with the hinge portion 13 as a fulcrum can be changed.

FIG. 3A shows an example of use when display is performed only in the display area 12b. At this time, the display area 12a can be turned off to save power. The display may be performed only in the display area 12a. By setting the surface opposite to the first surface of the housing 11a and the surface opposite to the first surface of the housing 11b to face each other, an operation like a tablet terminal can be performed.

In FIG. 3B, an angle formed by a surface opposite to the first surface of the housing 11a and a surface opposite to the first surface of the housing 11b is an acute angle, and the display regions 12a and 12b are outward and horizontally long. The example used with the form which becomes is illustrated. In this case, display may be performed on one of the display areas 12a and 12b, or display may be performed on both. When displaying both, the image can be visually recognized by the second viewer even on the side facing the electronic device 10 of the first viewer.

FIG. 3C shows an example of use such as when carrying and storing. By adopting a form in which the first surface of the housing 11a and the first surface of the housing 11b are closed to face each other, damage to the display areas 12a and 12b can be prevented.

The electronic device 10 is preferably provided with a sensor 14. For example, as the sensor 14, an angle sensor, an illuminance sensor, or the like can be used.

The angle sensor is a sensor that detects the spatial orientation of the electronic device 10, and can determine the orientation of the images displayed in the display areas 12a and 12b. Further, by using the illuminance sensor, it is possible to detect the external light intensity and switch to a display mode suitable for the use environment. Note that the electronic device 10 may include both an angle sensor and an illuminance sensor.

In the above description, the display area 12a used as the sub screen may be inferior in visibility. However, the first display element (reflection liquid crystal element) that can be used in the display area 12a is external light. When the strength is high, the visibility is superior to the second display element (light emitting element) that can be used for the display region 12b. Therefore, it is preferable to switch the display mode of the display area 12b according to the external light intensity.

For example, a mode in which display is performed with the second display element is selected in a dark room or outdoors at night, and a mode in which the first display element and the second display element are used together or the second display is selected in a bright room. It is preferable to select a mode in which display is performed by the element and to select a mode in which display is performed by the first display element when outdoors with strong external light. Therefore, depending on the selected display mode, the visibility of the display area 12a and the display area 12b may be equivalent.

In addition, the electronic device of one embodiment of the present invention may include a display device different from the electronic device 10 as illustrated in FIGS.

The electronic device 20 shown in FIGS. 4A and 4B can be used for the same application as the electronic device 10, and includes a housing 21a, a housing 21b, a display area 22a, and a display area 22b. One or both of the display area 22a and the display area 22b includes a touch sensor as input means.

The display area 22a has an area overlapping with the casing 21a, and the display area 22b has an area overlapping with the casing 21b. Moreover, the housing | casing 21a is connected with the housing | casing 21b via the hinge part 23, and the angle which the housing | casing 21a and the housing | casing 21b comprise can be changed by using the hinge part 23 as a fulcrum.

Each of the display area 22a and the display area 22b includes a first display element. In addition, one or both of the display area 22a and the display area 22b further includes a second display element.

That is, one of the display region 22a and the display region 22b can perform display with the first display element, the second display element, or the first display element and the second display element.

In addition, the other of the display region 22a and the display region 22b can perform display with at least the first display element. Further, when the second display element is provided, display can be performed using the second display element or the first display element and the second display element.

Specifically, the display area 22a is a first display area of the display panel 22 provided in the casing 21a and the casing 21b, and the display area 22b is a second display area of the display panel 22. The display panel 22 has flexibility. That is, the first display area and the second display area of the display panel 22 can be provided with the first display element, and the second display area can be provided with the second display element. . Alternatively, the first display area and the second display area of the display panel 22 may be provided with a first display element and a second display element, respectively.

For example, when the display area 22a is provided with the first display element and the display area 22b is provided with the first display element and the second display element, the display area 22a can be used as the sub-screen described above, The display area 22b can be used as a main screen. Further, when the display area 22a includes the first display element and the second display element, the display areas 22a and 22b can be used by appropriately switching between the main and sub screens.

The electronic device 20 is preferably provided with a sensor 24. For example, as the sensor 24, an angle sensor, an illuminance sensor, or the like can be used similarly to the sensor 14. Further, the sensor 24 may have a function of recognizing an angle formed by the housing 21a and the housing 21b. For example, when the angle is 90 ° to 120 ° C., that is, as shown in FIG. 4B, the sensor 24 outputs a signal and the display area 22a is displayed on the first display element. It can be. The form as shown in FIG. 4B is a form that is assumed to be input with the keys displayed in the display area 22a as in FIG. 2B, so that the display of the display area 22a is displayed on the first display element. It is preferable to reduce power consumption.

In order to recognize the angle formed by the housing 21a and the housing 21b, a switch that is turned on or off at a certain angle may be provided. A signal when the switch is on or off may be detected to switch the display of the display area 22a.

5A and 5B is a modified example of FIGS. 4A and 4B, and a display region 32a and a display region 32b are provided in a flexible casing 31. FIG. This is an example in which a display panel 32 is provided. The display area 32 a and the display area 32 b included in the display panel 32 can have the same configuration as the display area 22 a and the display area 22 b included in the display panel 22. 5A and 5B show an example in which the size of the display area 32a used as the secondary screen is small and the display area 32b used as the main screen is large. Both are the same size. May be.

In addition, the display area 32a and the display area 32b are display areas of the first display panel provided in the housing 31 as the display area 32a included in the display panel 32, as in the electronic device 10 illustrated in FIG. May be the display area of the second display panel provided in the housing 31.

For example, the housing 31 is mainly formed of a resin, a rubber-based resin, or the like, and may include a metal or the like if used within the elastic limit.

FIG. 5A illustrates an example in which the display panel 32 is used in a portrait orientation without bending the housing 31. For example, the lower part of the display panel 32 can be used like a tablet terminal with the display area 32a and the upper part as the display area 32b.

At least the display area 32a is provided with a touch sensor, and a character or the like can be input using the stylus 35 or the like.

Further, when the flexible casing 31 is bent, it can be used in the form of a notebook computer as shown in FIG. In addition, although the hinge part may be provided in the inside of the housing | casing 31, the housing | casing 31 may serve as the role of a hinge part.

The electronic device 30 includes a sensor 34 similar to the sensor 24, and can detect a bending angle of the housing 31 and change a display element used in the display region 32a.

Further, when the display area 32a is displayed using the first display element (reflection type liquid crystal element), the display area 32a may be extremely difficult to visually recognize in an environment with low illuminance. In such a case, as shown in FIG. 5C, the second display element in the region 36 that is a part of the display region 32b may emit light in white or the like to improve the visibility of the display region 32a. . In FIG. 5C, the area 36 is illustrated as being positioned at the lower end of the display area 32b, but may be positioned at the lower end of the display area 32b. Further, the function of causing part of the display area 32b to emit light can also include the electronic devices 10 and 20 described above.

A metal oxide is preferably used for a semiconductor layer in a semiconductor device such as a pixel included in each display region described above or a transistor used in a circuit for driving the pixel. As the metal oxide, for example, a CAC-OS (Cloud Aligned Complementary-Oxide Semiconductor) described later can be used.

In particular, an oxide semiconductor having a larger band gap than silicon is preferably used. When a semiconductor material having a wider band gap and lower carrier density than silicon is used, current in an off state of the transistor can be reduced.

In addition, due to the low off-state current, the charge accumulated in the capacitor through the transistor can be held for a long time. By applying such a transistor to a pixel, the driving circuit can be stopped while maintaining the gradation of an image displayed in each display region. As a result, an electronic device with extremely low power consumption can be realized.

A polycrystalline semiconductor may be used for a semiconductor device such as a pixel included in each display region described above or a transistor used in a circuit for driving the pixel. For example, it is preferable to use polycrystalline silicon. Polycrystalline silicon can be formed at a lower temperature than single crystal silicon, and has higher field effect mobility and higher reliability than amorphous silicon. By applying such a polycrystalline semiconductor to a pixel, the aperture ratio of the pixel can be improved. In addition, even when a large number of pixels are included, the gate driver circuit and the source driver circuit can be formed over the same substrate as the pixel, and the number of components included in the electronic device can be reduced.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

(Embodiment 2)
In this embodiment, a display device that can be used for one embodiment of the present invention and a method for driving the display device will be described.

The display device of one embodiment of the present invention can include a pixel provided with a first display element that reflects visible light. Alternatively, a pixel provided with a second display element that emits visible light can be provided. Alternatively, the pixel can include a third display element that transmits visible light. Alternatively, the pixel can include a first display element and a second display element or a third display element.

In this embodiment mode, a display device including a first display element that reflects visible light and a second display element that emits visible light will be described.

The display device has a function of displaying an image with one or both of first light reflected by the first display element and second light emitted by the second display element. Alternatively, the display device functions to express gradation by controlling the amount of first light reflected by the first display element and the amount of second light emitted by the second display element, respectively. Have

In addition, the display device controls the first pixel that expresses gradation by controlling the amount of reflected light from the first display element, and the gradation by controlling the amount of light emitted from the second display element. A structure including the second pixel to be expressed is preferable. A plurality of first pixels and second pixels are arranged in a matrix, for example, and constitute a display unit.

In addition, it is preferable that the first pixels and the second pixels are arranged in the display area with the same number and the same pitch. At this time, the adjacent first pixel and second pixel can be collectively referred to as a pixel unit. Thereby, as will be described later, an image displayed with only the plurality of first pixels, an image displayed with only the plurality of second pixels, and both the plurality of first pixels and the plurality of second pixels. Each of the images displayed in can be displayed in the same display area.

As the first display element included in the first pixel, an element that reflects external light for display can be used. Since such an element does not have a light source, power consumption during display can be extremely reduced.

As the first display element, a reflective liquid crystal element can be typically used. Alternatively, as a first display element, in addition to a shutter-type MEMS (Micro Electro Mechanical System) element, an optical interference-type MEMS element, a microcapsule type, an electrophoretic method, an electrowetting method, and an electronic powder fluid (registered trademark) An element to which a method or the like is applied can be used.

The second display element included in the second pixel includes a light source, and an element that performs display using light from the light source can be used. In particular, an electroluminescent element that can extract light emitted from a light-emitting substance by applying an electric field is preferably used. The light emitted from such a pixel is not affected by the brightness or chromaticity of the light, and therefore has high color reproducibility (wide color gamut) and high contrast, that is, vivid display. be able to.

As the second display element, for example, a self-luminous light emitting element such as an OLED (Organic Light Emitting Diode), an LED (Light Emitting Diode), a QLED (Quantum-Dot Light Emitting Diode), or a semiconductor laser can be used. Alternatively, as the display element included in the second pixel, a combination of a backlight that is a light source and a transmissive liquid crystal element that controls the amount of light transmitted through the backlight may be used.

The first pixel can include a sub-pixel that exhibits, for example, white (W), or a sub-pixel that exhibits three colors of light, for example, red (R), green (G), and blue (B). . Similarly, the second pixel has a sub-pixel that exhibits, for example, white (W), or a sub-pixel that exhibits light of three colors, for example, red (R), green (G), and blue (B). can do. Note that the subpixels included in each of the first pixel and the second pixel may have four or more colors. As the number of subpixels increases, power consumption can be reduced and color reproducibility can be improved.

According to one embodiment of the present invention, a first mode in which an image is displayed with a first pixel, a second mode in which an image is displayed with a second pixel, and an image is displayed with the first pixel and the second pixel. The third mode can be switched.

The first mode is a mode in which an image is displayed using reflected light from the first display element. The first mode is a driving mode with extremely low power consumption because no light source is required. For example, it is effective when the illuminance of outside light is sufficiently high and the outside light is white light or light in the vicinity thereof. The first mode is a display mode suitable for displaying character information such as books and documents. In addition, since the reflected light is used, it is possible to perform display that is kind to the eyes, and the effect that the eyes are less tired is achieved.

In the second mode, an image is displayed using light emitted from the second display element. Therefore, an extremely vivid display (high contrast and high color reproducibility) can be performed regardless of the illuminance and chromaticity of external light. For example, it is effective when the illuminance of outside light is extremely small, such as at night or in a dark room. Further, when the outside light is dark, the user may feel dazzled when performing bright display. In order to prevent this, it is preferable to perform display with reduced luminance in the second mode. Thereby, in addition to suppressing glare, power consumption can also be reduced. The second mode is a mode suitable for displaying a vivid image or a smooth moving image.

In the third mode, display is performed using both reflected light from the first display element and light emission from the second display element. Specifically, driving is performed so as to express one color by mixing light emitted by the first pixel and light emitted by the second pixel adjacent to the first pixel. While displaying more vividly than in the first mode, it is possible to suppress power consumption as compared with the second mode. For example, it is effective when the illuminance of outside light is relatively low, such as under room lighting or in the morning or evening hours, or when the chromaticity of outside light is not white. Further, by using light in which reflected light and light emission are mixed, it is possible to display an image that makes it feel as if the user is looking at a painting.

Hereinafter, more specific examples of one embodiment of the present invention will be described with reference to the drawings.

[Configuration example of display device]
6A illustrates the display panel 32 illustrated in FIGS. 5A to 5C. The display panel 32 has a display area 32a and a display area 32b.

The display area 32a has a plurality of pixel units 45a arranged in a matrix. The pixel unit 45 a includes a first pixel 46 and a second pixel 47.

The display area 32b has a plurality of pixel units 45b arranged in a matrix. The pixel unit 45 b includes a second pixel 47.

FIG. 6A illustrates an example in which the first pixel 46 and the second pixel 47 each include display elements corresponding to three colors of red (R), green (G), and blue (B). ing.

The first pixel 46 includes a display element 46R corresponding to red (R), a display element 46G corresponding to green (G), and a display element 46B corresponding to blue (B). Each of the display elements 46R, 46G, and 46B is a first display element that utilizes reflection of external light.

The second pixel 47 includes a display element 47R corresponding to red (R), a display element 47G corresponding to green (G), and a display element 47B corresponding to blue (B). Each of the display elements 47R, 47G, and 47B is a second display element that uses light from a light source.

Note that as shown in FIG. 6B, the display region 32b can also have a pixel unit 45a.

The above is the description of the configuration example of the display device.

[Configuration example of pixel unit]
Subsequently, the pixel unit 45a will be described with reference to FIGS. 7A, 7B, and 7C. FIGS. 7A, 7B, and 7C are schematic views illustrating a configuration example of the pixel unit 45a.

The first pixel 46 includes a display element 46R, a display element 46G, and a display element 46B. The display element 46 </ b> R reflects external light and emits red light R <b> 1 having a luminance corresponding to a gradation value corresponding to red included in the first gradation value input to the first pixel 46 on the display surface side. To ejaculate. Similarly, the display element 46G and the display element 46B respectively emit green light G1 or blue light B1 to the display surface side.

The second pixel 47 includes a display element 47R, a display element 47G, and a display element 47B. The display element 47R has a light source and emits red light R2 having a luminance corresponding to the gradation value corresponding to red included in the second gradation value input to the second pixel 47 on the display surface side. Eject. Similarly, the display element 47G and the display element 47B respectively emit green light G2 or blue light B2 to the display surface side.

[Third mode]
FIG. 7A illustrates an operation in which an image is displayed by driving both the display element 46R, the display element 46G, and the display element 46B that reflect external light, and the display element 47R, the display element 47G, and the display element 47B that emit light. An example of the mode is shown. As shown in FIG. 7A, the pixel unit 45a mixes six lights of light R1, light G1, light B1, light R2, light G2, and light B2 to mix light 55 of a predetermined color. It can be emitted to the display surface side.

At this time, it is preferable to suppress the luminance of each of the display element 47R, the display element 47G, and the display element 47B. For example, when the maximum value of the luminance of light that can be emitted from each of the display element 47R, the display element 47G, and the display element 47B (also referred to as the maximum luminance) is 100%, the display element 47R and the display in the third mode are displayed. It is preferable that the maximum value of the luminance of light emitted from each of the element 47G and the display element 47B is 5% to 50%, preferably 1% to 60% of the maximum luminance. As a result, it is possible to display with low power consumption, and the displayed image becomes more pictorial, and it is possible to perform display friendly to the eyes.

[First mode]
FIG. 7B illustrates an example of an operation mode in which an image is displayed by driving the display element 46R, the display element 46G, and the display element 46B that reflect external light. As shown in FIG. 7B, the pixel unit 45a does not drive the second pixel 47, for example, when the illuminance of outside light is sufficiently high, and does not drive the light (light R1) from the first pixel 46. By mixing only the light G1 and the light B1), it is possible to emit light 55 of a predetermined color to the display surface side. Thereby, driving with extremely low power consumption can be performed.

[Second mode]
FIG. 7C illustrates an example of an operation mode in which the display element 47R, the display element 47G, and the display element 47B are driven to display an image. As shown in FIG. 7C, the pixel unit 45a does not drive the first pixel 46, for example, when the illuminance of outside light is extremely small, and does not drive the light from the second pixel 47 (light R2,. By mixing only the light G2 and the light B2), the light 55 having a predetermined color can be emitted to the display surface side. Thereby, a vivid display can be performed. Further, by reducing the luminance when the illuminance of outside light is small, it is possible to suppress glare that the user feels and to reduce power consumption.

At this time, it is preferable to increase the luminance of the display element that emits visible light, as compared with the third mode. For example, the maximum value of the luminance of light emitted from each of the display element 47R, the display element 47G, and the display element 47B in the second mode is set to 100% of the maximum luminance, or 50% or more and 100% or less, preferably 60 % Or more and 100% or less. Thereby, a vivid image can be displayed even in a place where the outside light is bright.

Here, the maximum value of the luminance of light emitted from each of the display element 47R, the display element 47G, and the display element 47B can be replaced with a dynamic range. That is, in the third mode, the dynamic ranges of the display element 47R, the display element 47G, and the display element 47B can be set narrower than in the second mode. For example, the dynamic range of the third mode in the display element 47R, the display element 47G, or the display element 47B is set to 5% to 50%, preferably 1% to 60% of the dynamic range of the second mode. Can do.

The above is the description of the configuration example of the pixel unit 45a. Note that in the structure illustrated in FIG. 6A, since the pixel unit 45b does not include the first pixel 47, display can be performed only in the first mode with low power consumption.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

(Embodiment 3)
Examples of display panels that can be used for the display device of one embodiment of the present invention are described below. The display panel exemplified below is a display panel that includes both a reflective liquid crystal element and a light-emitting element and can perform both transmission mode and reflection mode displays.

[Configuration example]
FIG. 8A is a block diagram illustrating an example of a structure of the display device 400. The display device 400 includes a plurality of pixels 410 arranged in a matrix on the display portion 362. The display device 400 includes a circuit GD and a circuit SD. In addition, a plurality of pixels 410 arranged in the direction R, a plurality of wirings G1 electrically connected to the circuit GD, a plurality of wirings G2, a plurality of wirings ANO, and a plurality of wirings CSCOM are provided. In addition, a plurality of pixels 410 arranged in the direction C, a plurality of wirings S1 electrically connected to the circuit SD, and a plurality of wirings S2 are provided.

Here, for the sake of simplicity, a configuration having one circuit GD and one circuit SD is shown, but the circuit GD and the circuit SD that drive the liquid crystal element and the circuit GD and the circuit SD that drive the light emitting element are separately provided. May be provided.

The pixel 410 includes a reflective liquid crystal element and a light-emitting element. In the pixel 410, the liquid crystal element and the light-emitting element have portions that overlap each other.

FIG. 8B1 illustrates a configuration example of the conductive layer 311b included in the pixel 410. The conductive layer 311b functions as a reflective electrode of the liquid crystal element in the pixel 410. In addition, an opening 451 is provided in the conductive layer 311b.

In FIG. 8B1, the light-emitting element 360 located in a region overlapping with the conductive layer 311b is indicated by a broken line. The light-emitting element 360 is disposed so as to overlap with the opening 451 included in the conductive layer 311b. Thereby, the light emitted from the light emitting element 360 is emitted to the display surface side through the opening 451.

In FIG. 8B1, the pixels 410 adjacent in the direction R are pixels corresponding to different colors. At this time, as illustrated in FIG. 8B1, it is preferable that the openings 451 are provided at different positions in the conductive layer 311b so that the two pixels adjacent to each other in the direction R are not arranged in a line. Accordingly, the two light-emitting elements 360 can be separated from each other, and a phenomenon (also referred to as crosstalk) in which light emitted from the light-emitting elements 360 enters the colored layer of the adjacent pixel 410 can be suppressed. In addition, since the two adjacent light emitting elements 360 can be arranged apart from each other, a display device with high definition can be realized even when the EL layer of the light emitting element 360 is separately formed using a shadow mask or the like.

Alternatively, an arrangement as shown in FIG.

If the ratio of the total area of the openings 451 to the total area of the non-openings is too large, the display using the liquid crystal element becomes dark. If the ratio of the total area of the openings 451 to the total area of the non-openings is too small, the display using the light emitting element 360 is darkened.

In addition, when the area of the opening 451 provided in the conductive layer 311b functioning as the reflective electrode is too small, the efficiency of light that can be extracted from the light emitted from the light-emitting element 360 is reduced.

The shape of the opening 451 can be, for example, a polygon, a rectangle, an ellipse, a circle, a cross, or the like. Moreover, it is good also as an elongated streak shape, a slit shape, and a checkered shape. Further, the opening 451 may be arranged close to adjacent pixels. Preferably, the opening 451 is arranged close to other pixels displaying the same color. Thereby, crosstalk can be suppressed.

[Circuit configuration example]
FIG. 9 is a circuit diagram illustrating a configuration example of the pixel 410. In FIG. 9, two adjacent pixels 410 are shown.

The pixel 410 includes a switch SW1, a capacitor C1, a liquid crystal element 340, a switch SW2, a transistor M, a capacitor C2, a light emitting element 360, and the like. In addition, the pixel 410 is electrically connected to a wiring G1, a wiring G2, a wiring ANO, a wiring CSCOM, a wiring S1, and a wiring S2. In FIG. 9, a wiring VCOM1 electrically connected to the liquid crystal element 340 and a wiring VCOM2 electrically connected to the light-emitting element 360 are illustrated.

FIG. 9 shows an example in which transistors are used for the switch SW1 and the switch SW2.

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

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

FIG. 9 shows an example in which the transistor M has two gates sandwiching a semiconductor and these are connected. As a result, the current that can be passed by the transistor M can be increased.

A signal for controlling the switch SW1 to be in a conductive state or a non-conductive state can be supplied to the wiring G1. A predetermined potential can be applied to the wiring VCOM1. A signal for controlling the alignment state of the liquid crystal included in the liquid crystal element 340 can be supplied to the wiring S1. A predetermined potential can be applied to the wiring CSCOM.

A signal for controlling the switch SW2 to be in a conductive state or a non-conductive state can be supplied to the wiring G2. The wiring VCOM2 and the wiring ANO can each be supplied with a potential at which a potential difference generated by the light emitting element 360 emits light. A signal for controlling the conduction state of the transistor M can be supplied to the wiring S2.

For example, in the case of performing reflection mode display, the pixel 410 illustrated in FIG. 9 can be driven by a signal supplied to the wiring G1 and the wiring S1 and can display using optical modulation by the liquid crystal element 340. Further, in the case where display is performed in the transmissive mode, display can be performed by driving the light-emitting element 360 to emit light by driving with signals given to the wiring G2 and the wiring S2. In the case of driving in both modes, the driving can be performed by signals given to the wiring G1, the wiring G2, the wiring S1, and the wiring S2.

Note that although FIG. 10 illustrates an example in which one pixel 410 includes one liquid crystal element 340 and one light emitting element 360, the present invention is not limited thereto. FIG. 10A illustrates an example in which one pixel 410 includes one liquid crystal element 340 and four light-emitting elements 360 (light-emitting elements 360r, 360g, 360b, and 360w).

In FIG. 10A, in addition to the example of FIG. 9, a wiring G3 and a wiring S3 are connected to the pixel 410.

In the example illustrated in FIG. 10A, for example, as the four light-emitting elements 360, light-emitting elements that exhibit red (R), green (G), blue (B), and white (W) can be used. As the liquid crystal element 340, a reflective liquid crystal element exhibiting white can be used. Thereby, when displaying in reflection mode, white display with high reflectance can be performed. In addition, when display is performed in the transmissive mode, display with high color rendering properties can be performed with low power.

FIG. 10B illustrates a configuration example of the pixel 410. The pixel 410 includes a light-emitting element 360 w that overlaps with an opening included in the electrode 311, and a light-emitting element 360 r, a light-emitting element 360 g, and a light-emitting element 360 b that are disposed around the electrode 311. The light emitting element 360r, the light emitting element 360g, and the light emitting element 360b preferably have substantially the same light emitting area.

[Display panel configuration example]
FIG. 11 is a schematic perspective view of a display panel 300 of one embodiment of the present invention. The display panel 300 has a structure in which a substrate 351 and a substrate 361 are attached to each other. In FIG. 11, the substrate 361 is indicated by a broken line.

The display panel 300 includes a display portion 362, a circuit 364, a wiring 365, and the like. The substrate 351 is provided with, for example, a circuit 364, a wiring 365, a conductive layer 311b functioning as a pixel electrode, and the like. FIG. 11 shows an example in which an IC 373 and an FPC 372 are mounted on a substrate 351. Therefore, the structure illustrated in FIG. 11 can also be referred to as a display module including the display panel 300, the FPC 372, and the IC 373.

As the circuit 364, for example, a circuit functioning as a scan line driver circuit can be used.

The wiring 365 has a function of supplying a signal and power to the display portion and the circuit 364. The signal and power are input to the wiring 365 from the outside or the IC 373 via the FPC 372.

FIG. 11 illustrates an example in which the IC 373 is provided on the substrate 351 by a COG (Chip On Glass) method or the like. As the IC 373, for example, an IC having a function as a scan line driver circuit, a signal line driver circuit, or the like can be used. Note that in the case where the display panel 300 includes a circuit that functions as a scanning line driver circuit and a signal line driver circuit, or a circuit that functions as a scanning line driver circuit or a signal line driver circuit is provided outside, and the display panel 300 is driven through the FPC 372. For example, the IC 373 may not be provided in the case of inputting a signal to do so. Further, the IC 373 may be mounted on the FPC 372 by a COF (Chip On Film) method or the like.

FIG. 11 shows an enlarged view of a part of the display unit 362. In the display portion 362, conductive layers 311b included in the plurality of display elements are arranged in a matrix. The conductive layer 311b has a function of reflecting visible light, and functions as a reflective electrode of a liquid crystal element 340 described later.

In addition, as illustrated in FIG. 11, the conductive layer 311b has an opening. Further, the light-emitting element 360 is provided on the substrate 351 side of the conductive layer 311b. Light from the light-emitting element 360 is emitted to the substrate 361 side through the opening of the conductive layer 311b.

Further, a touch sensor can be provided over the substrate 361. For example, a structure may be employed in which a sheet-like capacitive touch sensor 366 is provided over the display portion 362. Alternatively, a touch sensor may be provided between the substrate 361 and the substrate 351. In the case where a touch sensor is provided between the substrate 361 and the substrate 351, an optical touch sensor using a photoelectric conversion element may be used in addition to the capacitive touch sensor.
[Section configuration example]
FIG. 12 illustrates an example of a cross section of the display panel illustrated in FIG. 11 when a part of the region including the FPC 372, a part of the region including the circuit 364, and a part of the region including the display portion 362 are cut. Show. Note that the touch sensor 366 is not included.

The display panel includes an insulating layer 220 between the substrate 351 and the substrate 361. In addition, the light-emitting element 360, the transistor 201, the transistor 205, the transistor 206, the coloring layer 134, and the like are provided between the substrate 351 and the insulating layer 220. In addition, a liquid crystal element 340, a coloring layer 131, and the like are provided between the insulating layer 220 and the substrate 361. In addition, the substrate 361 and the insulating layer 220 are bonded through an adhesive layer 141, and the substrate 351 and the insulating layer 220 are bonded through an adhesive layer 142.

The transistor 206 is electrically connected to the liquid crystal element 340, and the transistor 205 is electrically connected to the light-emitting element 360. Since both the transistor 205 and the transistor 206 are formed over the surface of the insulating layer 220 on the substrate 351 side, they can be manufactured using the same process.

The substrate 361 is provided with a coloring layer 131, a light shielding layer 132, an insulating layer 121, a conductive layer 113 functioning as a common electrode of the liquid crystal element 340, an alignment film 133b, an insulating layer 117, and the like. The insulating layer 117 functions as a spacer for maintaining the cell gap of the liquid crystal element 340.

On the substrate 351 side of the insulating layer 220, insulating layers such as an insulating layer 211, an insulating layer 212, an insulating layer 213, an insulating layer 214, and an insulating layer 215 are provided. A part of the insulating layer 211 functions as a gate insulating layer of each transistor. The insulating layer 212, the insulating layer 213, and the insulating layer 214 are provided so as to cover each transistor. An insulating layer 215 is provided to cover the insulating layer 214. The insulating layer 214 and the insulating layer 215 function as a planarization layer. Note that although the case where the insulating layer covering the transistor and the like has three layers of the insulating layer 212, the insulating layer 213, and the insulating layer 214 is described here, the number of layers is not limited to this, and four or more layers may be used. It may be a layer or two layers. The insulating layer 214 functioning as a planarization layer is not necessarily provided if not necessary.

The transistor 201, the transistor 205, and the transistor 206 include a conductive layer 221 that partially functions as a gate, a conductive layer 222 that partially functions as a source or a drain, and a semiconductor layer 231. Here, the same hatching pattern is given to a plurality of layers obtained by processing the same conductive film.

The liquid crystal element 340 is a reflective liquid crystal element. The liquid crystal element 340 has a stacked structure in which a conductive layer 311a, a liquid crystal 112, and a conductive layer 113 are stacked. In addition, a conductive layer 311b that reflects visible light is provided in contact with the conductive layer 311a on the substrate 351 side. The conductive layer 311b has an opening 251. The conductive layer 311a and the conductive layer 113 include a material that transmits visible light. An alignment film 133 a is provided between the liquid crystal 112 and the conductive layer 311 a, and an alignment film 133 b is provided between the liquid crystal 112 and the conductive layer 113. In addition, a polarizing plate 130 is provided on the outer surface of the substrate 361.

In the liquid crystal element 340, the conductive layer 311b has a function of reflecting visible light, and the conductive layer 113 has a function of transmitting visible light. Light incident from the substrate 361 side is polarized by the polarizing plate 130, passes through the conductive layer 113 and the liquid crystal 112, and is reflected by the conductive layer 311b. Then, the light passes through the liquid crystal 112 and the conductive layer 113 again and reaches the polarizing plate 130. At this time, alignment of liquid crystal can be controlled by a voltage applied between the conductive layer 311b and the conductive layer 113, and optical modulation of light can be controlled. That is, the intensity of light emitted through the polarizing plate 130 can be controlled. In addition, light that is not in a specific wavelength region is absorbed by the colored layer 131, so that the extracted light is, for example, red light.

The light emitting element 360 is a bottom emission type light emitting element. The light-emitting element 360 has a stacked structure in which the conductive layer 191, the EL layer 192, and the conductive layer 193b are stacked in this order from the insulating layer 220 side. A conductive layer 193a is provided to cover the conductive layer 193b. The conductive layer 193b includes a material that reflects visible light, and the conductive layer 191 and the conductive layer 193a include a material that transmits visible light. Light emitted from the light-emitting element 360 is emitted to the substrate 361 side through the coloring layer 134, the insulating layer 220, the opening 251, the conductive layer 113, and the like.

Here, as illustrated in FIG. 12, the opening 251 is preferably provided with a conductive layer 311 a that transmits visible light. Accordingly, since the liquid crystal 112 is aligned in the region overlapping with the opening 251 similarly to the other regions, alignment failure of the liquid crystal occurs at the boundary portion between these regions, and unintended light leakage can be suppressed.

Here, a linear polarizing plate may be used as the polarizing plate 130 disposed on the outer surface of the substrate 361, but a circular polarizing plate may also be used. As a circularly-polarizing plate, what laminated | stacked the linearly-polarizing plate and the quarter wavelength phase difference plate, for example can be used. Thereby, external light reflection can be suppressed. In addition, a desired contrast may be realized by adjusting a cell gap, an alignment, a driving voltage, and the like of the liquid crystal element used for the liquid crystal element 340 depending on the type of the polarizing plate.

An insulating layer 217 is provided over the insulating layer 216 that covers the end portion of the conductive layer 191. The insulating layer 217 has a function as a spacer for suppressing the insulating layer 220 and the substrate 351 from approaching more than necessary. In the case where the EL layer 192 or the conductive layer 193a is formed using a shielding mask (metal mask), the EL layer 192 or the conductive layer 193a may function as a mask gapper for suppressing contact of the shielding mask with a formation surface. Good. Note that the insulating layer 217 is not necessarily provided if not necessary.

One of a source and a drain of the transistor 205 is electrically connected to the conductive layer 191 of the light-emitting element 360 through the conductive layer 224.

One of a source and a drain of the transistor 206 is electrically connected to the conductive layer 311b through the connection portion 207. The conductive layer 311b and the conductive layer 311a are provided in contact with each other and are electrically connected. Here, the connection portion 207 is a portion that connects the conductive layers provided on both surfaces of the insulating layer 220 through openings provided in the insulating layer 220.

A connection portion 204 is provided in a region of the substrate 351 that does not overlap with the substrate 361. The connection portion 204 is electrically connected to the FPC 372 through the connection layer 242. The connection unit 204 has the same configuration as the connection unit 207. A conductive layer obtained by processing the same conductive film as the conductive layer 311a is exposed on the upper surface of the connection portion 204. Accordingly, the connection unit 204 and the FPC 372 can be electrically connected via the connection layer 242.

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

As the connection body 243, for example, conductive particles can be used. As the conductive particles, those obtained by coating the surface of particles such as organic resin or silica with a metal material can be used. It is preferable to use nickel or gold as the metal material because the contact resistance can be reduced. In addition, it is preferable to use particles in which two or more kinds of metal materials are coated in layers, such as further coating nickel with gold. Further, it is preferable to use a material that is elastically deformed or plastically deformed as the connection body 243. At this time, the connection body 243, which is a conductive particle, may have a shape crushed in the vertical direction as shown in FIG. By doing so, the contact area between the connection body 243 and the conductive layer electrically connected to the connection body 243 can be increased, the contact resistance can be reduced, and the occurrence of problems such as connection failure can be suppressed.

The connection body 243 is preferably disposed so as to be covered with the adhesive layer 141. For example, the connection body 243 may be sprayed after applying a paste or the like to be the adhesive layer 141.

FIG. 12 illustrates an example in which the transistor 201 is provided as an example of the circuit 364.

In FIG. 12, as an example of the transistor 201 and the transistor 205, a structure in which a semiconductor layer 231 where a channel is formed is sandwiched between two gates is applied. One gate is formed of a conductive layer 221, and the other gate is formed of a conductive layer 223 that overlaps with the semiconductor layer 231 with an insulating layer 212 interposed therebetween. With such a structure, the threshold voltage of the transistor can be controlled. At this time, the transistor may be driven by connecting two gates and supplying the same signal thereto. Such a transistor can have higher field-effect mobility than other transistors, and can increase on-state current. As a result, a circuit that can be driven at high speed can be manufactured. Furthermore, the area occupied by the circuit portion can be reduced. By applying a transistor with a large on-state current, signal delay in each wiring can be reduced and display unevenness can be suppressed even if the number of wirings increases when the display panel is increased in size or definition. can do.

Note that the transistor included in the circuit 364 and the transistor included in the display portion 362 may have the same structure. In addition, the plurality of transistors included in the circuit 364 may have the same structure or may be combined with different structures. In addition, the plurality of transistors included in the display portion 362 may have the same structure or may be combined with transistors having different structures.

At least one of the insulating layer 212 and the insulating layer 213 that covers each transistor is preferably formed using a material in which impurities such as water and hydrogen hardly diffuse. That is, the insulating layer 212 or the insulating layer 213 can function as a barrier film. With such a structure, it is possible to effectively prevent impurities from diffusing from the outside to the transistor, and a highly reliable display panel can be realized.

On the substrate 361 side, the insulating layer 121 is provided so as to cover the colored layer 131 and the light-shielding layer 132. The insulating layer 121 may function as a planarization layer. Since the surface of the conductive layer 113 can be substantially flattened by the insulating layer 121, the alignment state of the liquid crystal 112 can be made uniform.

[About each component]
Below, each component shown above is demonstrated.

〔substrate〕
A substrate having a flat surface can be used for the substrate included in the display panel. For the substrate from which light from the display element is extracted, a material that transmits the light is used. For example, materials such as glass, quartz, ceramic, sapphire, and organic resin can be used.

By using a thin substrate, the display panel can be reduced in weight and thickness. Furthermore, a flexible display panel can be realized by using a flexible substrate.

Further, since the substrate on the side from which light emission is not extracted does not have to be translucent, a metal substrate or the like can be used in addition to the above-described substrates. A metal substrate is preferable because it has high thermal conductivity and can easily conduct heat to the entire substrate, which can suppress a local temperature increase of the display panel. In order to obtain flexibility and bendability, the thickness of the metal substrate is preferably 10 μm to 200 μm, and more preferably 20 μm to 50 μm.

Although there is no limitation in particular as a material which comprises a metal substrate, For example, metals, such as aluminum, copper, nickel, or alloys, such as aluminum alloy or stainless steel, can be used suitably.

Alternatively, a substrate that has been subjected to an insulating process by oxidizing the surface of the metal substrate or forming an insulating film on the surface may be used. For example, the insulating film may be formed by using a coating method such as a spin coating method or a dip method, an electrodeposition method, a vapor deposition method, or a sputtering method, or it is left in an oxygen atmosphere or heated, or an anodic oxidation method. For example, an oxide film may be formed on the surface of the substrate.

Examples of materials having flexibility and transparency to visible light include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resins, polyimide resins, polymethyl methacrylate resins, and polycarbonates. (PC) resin, polyethersulfone (PES) resin, polyamide resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyvinyl chloride resin, polytetrafluoroethylene (PTFE) resin, and the like. In particular, a material having a low thermal expansion coefficient is preferably used. For example, a polyamideimide resin, a polyimide resin, PET, or the like having a thermal expansion coefficient of 30 × 10 ⁻⁶ / K or less can be suitably used. Further, a substrate in which glass fiber is impregnated with an organic resin, or a substrate in which an inorganic filler is mixed with an organic resin to reduce the thermal expansion coefficient can be used. Since a substrate using such a material is light in weight, a display panel using the substrate can be lightweight.

When a fibrous body is included in the material, a high-strength fiber of an organic compound or an inorganic compound is used for the fibrous body. The high-strength fiber specifically refers to a fiber having a high tensile modulus or Young's modulus, and representative examples include polyvinyl alcohol fiber, polyester fiber, polyamide fiber, polyethylene fiber, aramid fiber, Examples include polyparaphenylene benzobisoxazole fibers, glass fibers, and carbon fibers. Examples of the glass fiber include glass fibers using E glass, S glass, D glass, Q glass, and the like. These may be used in the form of a woven fabric or a non-woven fabric, and a structure obtained by impregnating the fiber body with a resin and curing the resin may be used as a flexible substrate. When a structure made of a fibrous body and a resin is used as the flexible substrate, it is preferable because reliability against breakage due to bending or local pressing is improved.

Alternatively, glass, metal, or the like thin enough to have flexibility can be used for the substrate. Alternatively, a composite material in which glass and a resin material are bonded to each other with an adhesive layer may be used.

A hard coat layer (for example, silicon nitride, aluminum oxide) that protects the surface of the display panel from scratches, a layer of a material that can disperse the pressure (for example, aramid resin), etc. on a flexible substrate It may be laminated. In order to suppress a decrease in the lifetime of the display element due to moisture or the like, an insulating film with low water permeability may be stacked over a flexible substrate. For example, an inorganic insulating material such as silicon nitride, silicon oxynitride, silicon nitride oxide, aluminum oxide, or aluminum nitride can be used.

The substrate can be used by stacking a plurality of layers. In particular, when the glass layer is used, the barrier property against water and oxygen can be improved and a highly reliable display panel can be obtained.

[Transistor]
The transistor includes a conductive layer that functions as a gate electrode, a semiconductor layer, a conductive layer that functions as a source electrode, a conductive layer that functions as a drain electrode, and an insulating layer that functions as a gate insulating layer. The above shows the case where a bottom-gate transistor is applied.

Note that there is no particular limitation on the structure of the transistor included in the display device of one embodiment of the present invention. For example, a planar transistor, a staggered transistor, or an inverted staggered transistor may be used. Further, a top-gate or bottom-gate transistor structure may be employed. Alternatively, gate electrodes may be provided above and below the channel.

There is no particular limitation on the crystallinity of the semiconductor material used for the transistor, and either an amorphous semiconductor or a semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor partially including a crystal region) is used. May be used. It is preferable to use a crystalline semiconductor because deterioration of transistor characteristics can be suppressed.

As a semiconductor material used for the transistor, a metal oxide having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can be used. A typical example is an oxide semiconductor containing indium. For example, a CAC-OS described later can be used.

A transistor using an oxide semiconductor with a wider band gap and lower carrier density than silicon can hold charge accumulated in a capacitor connected in series with the transistor for a long time due to its low off-state current. Is possible.

The semiconductor layer is represented by an In-M-Zn-based oxide containing indium, zinc, and M (metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium). It can be a membrane.

In the case where the oxide semiconductor included in the semiconductor layer is an In-M-Zn-based oxide, the atomic ratio of the metal elements of the sputtering target used for forming the In-M-Zn oxide is In ≧ M, Zn It is preferable to satisfy ≧ M. As the atomic ratio of the metal elements of such a sputtering target, In: M: Zn = 1: 1: 1, In: M: Zn = 1: 1: 1.2, In: M: Zn = 3: 1: 2, In: M: Zn = 4: 2: 3, In: M: Zn = 4: 2: 4.1, In: M: Zn = 5: 1: 6, In: M: Zn = 5: 1: 7, In: M: Zn = 5: 1: 8 etc. are preferable. Note that the atomic ratio of the semiconductor layer to be formed includes a variation of plus or minus 40% of the atomic ratio of the metal element contained in the sputtering target.

The bottom-gate transistor described in this embodiment is preferable because the number of manufacturing steps can be reduced. In addition, by using an oxide semiconductor at this time, the wiring under the semiconductor layer can be formed at a temperature lower than that of polycrystalline silicon, and a material having low heat resistance can be used as an electrode material and a substrate material. Can widen the choice of materials. For example, a glass substrate having an extremely large area can be suitably used.

As the semiconductor layer, an oxide semiconductor film with low carrier density is used. For example, the semiconductor layer has a carrier density of 1 × 10 ¹⁷ / cm ³ or less, preferably 1 × 10 ¹⁵ / cm ³ or less, more preferably 1 × 10 ¹³ / cm ³ or less, more preferably 1 × 10 ¹¹ / cm 3. ³ or less, more preferably less than 1 × 10 ¹⁰ / cm ³ , and an oxide semiconductor having a carrier density of 1 × 10 ⁻⁹ / cm ³ or more can be used. Such an oxide semiconductor is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Accordingly, it can be said that the oxide semiconductor has stable characteristics because the impurity concentration is low and the density of defect states is low.

Note that the composition is not limited thereto, and a transistor having an appropriate composition may be used depending on required semiconductor characteristics and electrical characteristics (such as field-effect mobility and threshold voltage) of the transistor. In addition, in order to obtain the required semiconductor characteristics of the transistor, it is preferable that the semiconductor layer have appropriate carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, and the like. .

If an oxide semiconductor included in the semiconductor layer contains silicon or carbon which is one of Group 14 elements, oxygen vacancies increase in the semiconductor layer and the semiconductor layer becomes n-type. Therefore, the concentration of silicon or carbon in the semiconductor layer (concentration obtained by secondary ion mass spectrometry) is 2 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁷ atoms / cm ³ or less.

Further, when alkali metal and alkaline earth metal are combined with an oxide semiconductor, carriers may be generated, which may increase off-state current of the transistor. Therefore, the concentration of alkali metal or alkaline earth metal obtained by secondary ion mass spectrometry in the semiconductor layer is set to 1 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁶ atoms / cm ³ or less.

In addition, when nitrogen is contained in the oxide semiconductor included in the semiconductor layer, electrons serving as carriers are generated, the carrier density is increased, and the oxide semiconductor is likely to be n-type. As a result, a transistor including an oxide semiconductor containing nitrogen is likely to be normally on. For this reason, it is preferable that the nitrogen concentration obtained by secondary ion mass spectrometry in the semiconductor layer is 5 × 10 ¹⁸ atoms / cm ³ or less.

The semiconductor layer may have a non-single crystal structure, for example. The non-single-crystal structure includes, for example, a CAAC-OS (C-Axis Crystalline Oxide Semiconductor Semiconductor having a crystal oriented in the c-axis, or a C-Axis Aligned and A-B-Plane Annealed Crystal Oxide Crystal Structure, Includes a microcrystalline structure or an amorphous structure. In the non-single-crystal structure, the amorphous structure has the highest density of defect states, and the CAAC-OS has the lowest density of defect states.

An oxide semiconductor film having an amorphous structure has, for example, disordered atomic arrangement and no crystal component. Alternatively, an amorphous oxide film has, for example, a completely amorphous structure and does not have a crystal part.

Note that the semiconductor layer may be a mixed film including two or more of an amorphous structure region, a microcrystalline structure region, a polycrystalline structure region, a CAAC-OS region, and a single crystal structure region. Good. For example, the mixed film may have a single-layer structure or a stacked structure including any two or more of the above-described regions.
<Configuration of CAC-OS>
A structure of a CAC (Cloud Aligned Complementary) -OS that can be used for the transistor disclosed in one embodiment of the present invention is described below.

The CAC-OS is one structure of a material in which an element included in an oxide semiconductor is unevenly distributed with a size of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or the vicinity thereof. Note that in the following, in an oxide semiconductor, one or more metal elements are unevenly distributed, and a region including the metal element has a size of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or the vicinity thereof. The state mixed with is also referred to as a mosaic or patch.

Note that the oxide semiconductor preferably contains at least indium. In particular, it is preferable to contain indium and zinc. In addition, aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc. One kind selected from the above or a plurality of kinds may be included.

For example, a CAC-OS in In-Ga-Zn oxide (In-Ga-Zn oxide among CAC-OSs may be referred to as CAC-IGZO in particular) is an indium oxide (hereinafter referred to as InO). _X1 (X1 is greater real than 0) and.), or indium zinc oxide _{(hereinafter, in X2 Zn Y2 O Z2 (} X2, Y2, and Z2 is larger real than 0) and a.), gallium An oxide (hereinafter referred to as GaO _X3 (X3 is a real number greater than 0)) or a gallium zinc oxide (hereinafter referred to as Ga _X4 Zn _Y4 O _Z4 (where X4, Y4, and Z4 are greater than 0)) to.) and the like, the material becomes mosaic by separate into, mosaic _{InO X1} or _in X2 _Zn Y2 _{O Z2,} is a configuration in which uniformly distributed in the film (hereinafter Also referred to as a cloud-like.) A.

That, CAC-OS includes a region _{GaO X3} is the main _component, and In _{X2 Zn} Y2 _{O Z2,} or _{InO X1} is the main component region is a composite oxide semiconductor having a structure that is mixed. Note that in this specification, for example, the first region indicates that the atomic ratio of In to the element M in the first region is larger than the atomic ratio of In to the element M in the second region. It is assumed that the concentration of In is higher than that in the second region.

Note that IGZO is a common name and may refer to one compound of In, Ga, Zn, and O. As a typical example, InGaO ₃ (ZnO) _m1 (m1 is a natural number) or In _{(1 + x0)} Ga _(1-x0) O ₃ (ZnO) _m0 (−1 ≦ x0 ≦ 1, m0 is an arbitrary number) A crystalline compound may be mentioned.

The crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. The CAAC structure is a crystal structure in which a plurality of IGZO nanocrystals have c-axis orientation and are connected without being oriented in the ab plane.

On the other hand, CAC-OS relates to a material structure of an oxide semiconductor. CAC-OS refers to a region observed in the form of nanoparticles mainly composed of Ga in a material structure including In, Ga, Zn and O, and nanoparticles mainly composed of In. The region observed in a shape is a configuration in which the regions are randomly dispersed in a mosaic shape. Therefore, in the CAC-OS, the crystal structure is a secondary element.

Note that the CAC-OS does not include a stacked structure of two or more kinds of films having different compositions. For example, a structure composed of two layers of a film mainly containing In and a film mainly containing Ga is not included.

Incidentally, a region _{GaO X3} is the main _component, and In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component region, in some cases clear boundary can not be observed.

In place of gallium, aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium are selected. In the case where one or a plurality of types are included, the CAC-OS includes a region that is observed in a part of a nanoparticle mainly including the metal element and a nanoparticle mainly including In. The region observed in the form of particles refers to a configuration in which each region is randomly dispersed in a mosaic shape.

The CAC-OS can be formed by a sputtering method under a condition where the substrate is not intentionally heated, for example. In the case where a CAC-OS is formed by a sputtering method, any one or more selected from an inert gas (typically argon), an oxygen gas, and a nitrogen gas may be used as a deposition gas. Good. Further, the flow rate ratio of the oxygen gas to the total flow rate of the deposition gas during film formation is preferably as low as possible. .

The CAC-OS is characterized in that no clear peak is observed when it is measured using a θ / 2θ scan by the out-of-plane method, which is one of the X-ray diffraction (XRD) measurement methods. Have. That is, it can be seen from X-ray diffraction that no orientation in the ab plane direction and c-axis direction of the measurement region is observed.

In addition, in the CAC-OS, in an electron beam diffraction pattern obtained by irradiating an electron beam with a probe diameter of 1 nm (also referred to as a nanobeam electron beam), a ring-shaped high luminance region and a plurality of regions in the ring region are provided. A bright spot is observed. Therefore, it can be seen from the electron beam diffraction pattern that the crystal structure of the CAC-OS has an nc (nano-crystal) structure having no orientation in the planar direction and the cross-sectional direction.

In addition, for example, in a CAC-OS in an In—Ga—Zn oxide, GaO _X3 is a main component by EDX mapping obtained by using energy dispersive X-ray spectroscopy (EDX: Energy Dispersive X-ray spectroscopy). It can be confirmed that the region and the region mainly composed of In _X2 Zn _Y2 O _Z2 or InO _X1 are unevenly distributed and mixed.

The CAC-OS has a structure different from that of the IGZO compound in which the metal element is uniformly distributed, and has a property different from that of the IGZO compound. That is, in the CAC-OS, a region in which GaO _X3 or the like is a main component and a region in which In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component are phase-separated from each other, and each region is mainly composed of each element. Has a mosaic structure.

Here, the region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component is a region having higher conductivity than a region containing GaO _X3 or the like as a main component. _That, In _{X2 Zn} Y2 _{O Z2} or _{InO X1,} is an area which is the main component, by carriers flow, expressed the conductivity of the oxide semiconductor. Accordingly, a region where In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component is distributed in a cloud shape in the oxide semiconductor, whereby high field-effect mobility (μ) can be realized.

On the other hand, areas such as _{GaO X3} is the main _component, as compared to the In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component area, it is highly regions insulating. That is, a region containing GaO _X3 or the like as a main component is distributed in the oxide semiconductor, whereby leakage current can be suppressed and good switching operation can be realized.

Therefore, when CAC-OS is used for a semiconductor element, the insulating property caused by GaO _{X3 and the} like and the conductivity caused by In _X2 Zn _Y2 O _Z2 or InO _X1 act complementarily, thereby increasing the An on-current (I _on ) and high field effect mobility (μ) can be realized.

In addition, a semiconductor element using a CAC-OS has high reliability. Therefore, the CAC-OS is optimal for various semiconductor devices including a display.

Alternatively, silicon may be used for the semiconductor in which the channel of the transistor is formed. Although amorphous silicon may be used as silicon, it is particularly preferable to use silicon having crystallinity. For example, microcrystalline silicon, polycrystalline silicon, single crystal silicon, or the like is preferably used. In particular, polycrystalline silicon can be formed at a lower temperature than single crystal silicon, and has higher field effect mobility and higher reliability than amorphous silicon.

The bottom-gate transistor described in this embodiment is preferable because the number of manufacturing steps can be reduced. At this time, since amorphous silicon can be used at a lower temperature than polycrystalline silicon, it is possible to use a material having low heat resistance as the electrode material and substrate material for the wiring below the semiconductor layer. Can widen the choice of materials. For example, a glass substrate having an extremely large area can be suitably used. On the other hand, a top-gate transistor is preferable because an impurity region can be easily formed in a self-aligning manner and variation in characteristics can be reduced. At this time, it is particularly suitable when polycrystalline silicon, single crystal silicon or the like is used.

[Conductive layer]
In addition to the gate, source, and drain of a transistor, materials that can be used for conductive layers such as various wirings and electrodes that constitute a display device include aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, A metal such as tantalum or tungsten, or an alloy containing the same as a main component can be given. A film containing any of these materials can be used as a single layer or a stacked structure. For example, a single layer structure of an aluminum film containing silicon, a two layer structure in which an aluminum film is stacked on a titanium film, a two layer structure in which an aluminum film is stacked on a tungsten film, and a copper film on a copper-magnesium-aluminum alloy film Two-layer structure to stack, two-layer structure to stack copper film on titanium film, two-layer structure to stack copper film on tungsten film, titanium film or titanium nitride film, and aluminum film or copper film on top of it A three-layer structure for forming a titanium film or a titanium nitride film thereon, a molybdenum film or a molybdenum nitride film, and an aluminum film or a copper film stacked thereon, and a molybdenum film or a There is a three-layer structure for forming a molybdenum nitride film. Note that an oxide such as indium oxide, tin oxide, or zinc oxide may be used. Further, it is preferable to use copper containing manganese because the controllability of the shape by etching is increased.

As the light-transmitting conductive material, conductive oxide such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, or zinc oxide to which gallium is added, or graphene can be used. Alternatively, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or an alloy material containing the metal material can be used. Alternatively, a nitride (eg, titanium nitride) of the metal material may be used. Note that in the case where a metal material or an alloy material (or a nitride thereof) is used, it may be thin enough to have a light-transmitting property. In addition, a stacked film of the above materials can be used as a conductive layer. For example, it is preferable to use a laminated film of an alloy of silver and magnesium and indium tin oxide because the conductivity can be increased. These can also be used for conductive layers such as various wirings and electrodes constituting the display device and conductive layers (conductive layers functioning as pixel electrodes and common electrodes) included in the display element.

[Insulation layer]
Insulating materials that can be used for each insulating layer include, for example, resins such as acrylic and epoxy, resins having a siloxane bond, and inorganic insulation such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide. Materials can also be used.

In addition, the light-emitting element is preferably provided between a pair of insulating films with low water permeability. Thereby, impurities such as water can be prevented from entering the light emitting element, and a decrease in reliability of the apparatus can be suppressed.

Examples of the low water-permeable insulating film include a film containing nitrogen and silicon such as a silicon nitride film and a silicon nitride oxide film, and a film containing nitrogen and aluminum such as an aluminum nitride film. Alternatively, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or the like may be used.

For example, the water vapor transmission rate of an insulating film with low water permeability is 1 × 10 ⁻⁵ [g / (m ² · day)] or less, preferably 1 × 10 ⁻⁶ [g / (m ² · day)] or less, More preferably, it is 1 × 10 ⁻⁷ [g / (m ² · day)] or less, and further preferably 1 × 10 ⁻⁸ [g / (m ² · day)] or less.

[Liquid crystal element]
As the liquid crystal element, for example, a liquid crystal element to which a vertical alignment (VA: Vertical Alignment) mode is applied can be used. As the vertical alignment mode, an MVA (Multi-Domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, an ASV (Advanced Super View) mode, or the like can be used.

As the liquid crystal element, liquid crystal elements to which various modes are applied can be used. For example, in addition to the VA mode, a TN (Twisted Nematic) mode, an IPS (In-Plane-Switching) mode, an FFS (Fringe Field Switching) mode, an ASM (Axially Symmetrical Aligned Micro-cell) mode Further, a liquid crystal element to which an FLC (Ferroelectric Liquid Crystal) mode, an AFLC (Antiferroelectric Liquid Crystal) mode, or the like is applied can be used.

Note that a liquid crystal element is an element that controls transmission or non-transmission of light by an optical modulation action of liquid crystal. Note that the optical modulation action of the liquid crystal is controlled by an electric field applied to the liquid crystal (including a horizontal electric field, a vertical electric field, or an oblique electric field). As the liquid crystal used in the liquid crystal element, a thermotropic liquid crystal, a low molecular liquid crystal, a polymer liquid crystal, a polymer dispersed liquid crystal (PDLC), a ferroelectric liquid crystal, an antiferroelectric liquid crystal, or the like is used. Can do. These liquid crystal materials exhibit a cholesteric phase, a smectic phase, a cubic phase, a chiral nematic phase, an isotropic phase, and the like depending on conditions.

Further, as the liquid crystal material, either a positive type liquid crystal or a negative type liquid crystal may be used, and an optimal liquid crystal material may be used according to an applied mode or design.

An alignment film can be provided to control the alignment of the liquid crystal. Note that in the case of employing a horizontal electric field mode, liquid crystal exhibiting a blue phase for which an alignment film is unnecessary may be used. The blue phase is one of the liquid crystal phases. When the temperature of the cholesteric liquid crystal is increased, the blue phase appears immediately before the transition from the cholesteric phase to the isotropic phase. Since the blue phase appears only in a narrow temperature range, a liquid crystal composition mixed with several percent by weight or more of a chiral agent is used for the liquid crystal layer in order to improve the temperature range. A liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent has a short response speed and is optically isotropic. In addition, a liquid crystal composition including a liquid crystal exhibiting a blue phase and a chiral agent does not require alignment treatment and has a small viewing angle dependency. Further, since it is not necessary to provide an alignment film, a rubbing process is not required, so that electrostatic breakdown caused by the rubbing process can be prevented, and defects or breakage of the liquid crystal display device during the manufacturing process can be reduced. .

As the liquid crystal element, a transmissive liquid crystal element, a reflective liquid crystal element, a transflective liquid crystal element, or the like can be used.

In one embodiment of the present invention, a reflective liquid crystal element can be used.

In the case of using a transmissive or transflective liquid crystal element, two polarizing plates are provided so as to sandwich a pair of substrates. A backlight is provided outside the polarizing plate. The backlight may be a direct type backlight or an edge light type backlight. It is preferable to use a direct-type backlight including an LED (Light Emitting Diode) because local dimming is facilitated and contrast can be increased. An edge light type backlight is preferably used because the thickness of the module including the backlight can be reduced.
Therefore, it is preferable.

In the case of using a reflective liquid crystal element, a polarizing plate is provided on the display surface side. Separately from this, it is preferable to arrange a light diffusing plate on the display surface side because the visibility can be improved.

In the case of using a reflective or transflective liquid crystal element, a front light may be provided outside the polarizing plate. As the front light, an edge light type front light is preferably used. It is preferable to use a front light including an LED (Light Emitting Diode) because power consumption can be reduced.

[Light emitting element]
As the light-emitting element, an element capable of self-emission can be used, and an element whose luminance is controlled by current or voltage is included in its category. For example, an LED, an organic EL element, an inorganic EL element, or the like can be used.

Light emitting elements include a top emission type, a bottom emission type, and a dual emission type. A conductive film that transmits visible light is used for the electrode from which light is extracted. In addition, a conductive film that reflects visible light is preferably used for the electrode from which light is not extracted.

The EL layer has at least a light emitting layer. The EL layer is a layer other than the light-emitting layer, such as a substance having a high hole-injecting property, a substance having a high hole-transporting property, a hole blocking material, a substance having a high electron-transporting property, a substance having a high electron-injecting property, A layer including a substance (a substance having a high electron transporting property and a high hole transporting property) or the like may be further included.

In the EL layer, either a low molecular compound or a high molecular compound can be used, and an inorganic compound may be included. The layers constituting the EL layer can be formed by a method such as a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an ink jet method, or a coating method.

When a voltage higher than the threshold voltage of the light emitting element is applied between the cathode and the anode, holes are injected into the EL layer from the anode side and electrons are injected from the cathode side. The injected electrons and holes are recombined in the EL layer, and the light-emitting substance contained in the EL layer emits light.

In the case where a white light-emitting element is used as the light-emitting element, the EL layer preferably includes two or more light-emitting substances. For example, white light emission can be obtained by selecting the light emitting material so that the light emission of each of the two or more light emitting materials has a complementary color relationship. For example, a light emitting material that emits light such as R (red), G (green), B (blue), Y (yellow), and O (orange), or spectral components of two or more colors of R, G, and B It is preferable that 2 or more are included among the luminescent substances which show light emission containing. In addition, it is preferable to apply a light-emitting element whose emission spectrum from the light-emitting element has two or more peaks in a wavelength range of visible light (for example, 350 nm to 750 nm). The emission spectrum of the material having a peak in the yellow wavelength region is preferably a material having spectral components in the green and red wavelength regions.

The EL layer preferably has a structure in which a light-emitting layer including a light-emitting material that emits one color and a light-emitting layer including a light-emitting material that emits another color are stacked. For example, the plurality of light emitting layers in the EL layer may be stacked in contact with each other, or may be stacked through a region not including any light emitting material. For example, a region including the same material (for example, a host material or an assist material) as the fluorescent light emitting layer or the phosphorescent light emitting layer and not including any light emitting material is provided between the fluorescent light emitting layer and the phosphorescent light emitting layer. Also good. This facilitates the production of the light emitting element and reduces the driving voltage.

The light-emitting element may be a single element having one EL layer or a tandem element in which a plurality of EL layers are stacked with a charge generation layer interposed therebetween.

The conductive film that transmits visible light can be formed using, for example, indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide to which gallium is added, or the like. In addition, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, an alloy containing these metal materials, or a nitride of these metal materials (for example, Titanium nitride) can also be used by forming it thin enough to have translucency. In addition, a stacked film of the above materials can be used as a conductive layer. For example, it is preferable to use a stacked film of an alloy of silver and magnesium and indium tin oxide because the conductivity can be increased. Further, graphene or the like may be used.

For the conductive film that reflects visible light, for example, a metal material such as aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or an alloy including these metal materials is used. Can do. In addition, lanthanum, neodymium, germanium, or the like may be added to the metal material or alloy. Alternatively, titanium, nickel, or neodymium and an alloy containing aluminum (aluminum alloy) may be used. Alternatively, an alloy containing copper, palladium, magnesium, and silver may be used. An alloy containing silver and copper is preferable because of its high heat resistance. Furthermore, oxidation can be suppressed by stacking a metal film or a metal oxide film in contact with the aluminum film or the aluminum alloy film. Examples of materials for such metal films and metal oxide films include titanium and titanium oxide. Alternatively, the conductive film that transmits visible light and a film made of a metal material may be stacked. For example, a laminated film of silver and indium tin oxide, a laminated film of an alloy of silver and magnesium and indium tin oxide, or the like can be used.

The electrodes may be formed using a vapor deposition method or a sputtering method, respectively. In addition, it can be formed using a discharge method such as an inkjet method, a printing method such as a screen printing method, or a plating method.

Note that the above-described light-emitting layer and a layer containing a substance having a high hole-injecting property, a substance having a high hole-transporting property, a substance having a high electron-transporting property, a substance having a high electron-injecting property, a bipolar substance, Each may have an inorganic compound such as a quantum dot or a polymer compound (oligomer, dendrimer, polymer, etc.). For example, a quantum dot can be used for a light emitting layer to function as a light emitting material.

As the quantum dot material, a colloidal quantum dot material, an alloy type quantum dot material, a core / shell type quantum dot material, a core type quantum dot material, or the like can be used. Alternatively, a material including an element group of Group 12 and Group 16, Group 13 and Group 15, or Group 14 and Group 16 may be used. Alternatively, a quantum dot material containing an element such as cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium, lead, gallium, arsenic, or aluminum may be used.

[Adhesive layer]
As the adhesive layer, various curable adhesives such as an ultraviolet curable photocurable adhesive, a reactive curable adhesive, a thermosetting adhesive, and an anaerobic adhesive can be used. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenol resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, EVA (ethylene vinyl acetate) resins, and the like. In particular, a material with low moisture permeability such as an epoxy resin is preferable. Alternatively, a two-component mixed resin may be used. Further, an adhesive sheet or the like may be used.

Further, the resin may contain a desiccant. For example, a substance that adsorbs moisture by chemical adsorption, such as an alkaline earth metal oxide (such as calcium oxide or barium oxide), can be used. Alternatively, a substance that adsorbs moisture by physical adsorption, such as zeolite or silica gel, may be used. The inclusion of a desiccant is preferable because impurities such as moisture can be prevented from entering the element and the reliability of the display panel is improved.

In addition, light extraction efficiency can be improved by mixing a filler having a high refractive index or a light scattering member with the resin. For example, titanium oxide, barium oxide, zeolite, zirconium, or the like can be used.

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

(Colored layer)
Examples of materials that can be used for the colored layer include metal materials, resin materials, resin materials containing pigments or dyes, and the like.

[Light shielding layer]
Examples of the material that can be used for the light-shielding layer include carbon black, titanium black, metal, metal oxide, and composite oxide containing a solid solution of a plurality of metal oxides. The light shielding layer may be a film containing a resin material or a thin film of an inorganic material such as a metal. Alternatively, a stacked film of a film containing a material for the colored layer can be used for the light shielding layer. For example, a stacked structure of a film including a material used for a colored layer that transmits light of a certain color and a film including a material used for a colored layer that transmits light of another color can be used. It is preferable to use a common material for the coloring layer and the light-shielding layer because the apparatus can be shared and the process can be simplified.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

DESCRIPTION OF SYMBOLS 10 Electronic device 11a Case 11b Case 12a Display area 12b Display area 13 Hinge part 13a Shaft 13b Shaft 13c Bearing 13d Jig 14 Sensor 20 Electronic equipment 21a Case 21b Case 22 Display panel 22a Display area 22b Display area 23 Hinge part 24 sensor 30 electronic device 31 housing 32 display panel 32a display area 32b display area 34 sensor 35 stylus 36 area 45a pixel unit 45b pixel unit 46 pixel 46B display element 46G display element 46R display element 47 pixel 47B display element 47G display element 47R display Element 55 Light 112 Liquid crystal 113 Conductive layer 117 Insulating layer 121 Insulating layer 130 Polarizing plate 131 Colored layer 132 Light shielding layer 133a Oriented film 133b Oriented film 134 Colored layer 141 Adhesive layer 142 Adhesive layer 191 Conductive layer 192 EL layer 193a Conductive Layer 193b conductive layer 201 transistor 204 connection portion 205 transistor 206 transistor 207 connection portion 211 insulating layer 212 insulating layer 213 insulating layer 214 insulating layer 215 insulating layer 216 insulating layer 217 insulating layer 220 insulating layer 221 conductive layer 222 conductive layer 223 conductive layer 224 Conductive layer 231 Semiconductor layer 242 Connection layer 243 Connection body 251 Opening 252 Connection portion 300 Display panel 311 Electrode 311a Conductive layer 311b Conductive layer 340 Liquid crystal element 351 Substrate 360 Light emitting element 360b Light emitting element 360g Light emitting element 360r Light emitting element 360w Light emitting element 361 Substrate 362 Display unit 364 Circuit 365 Wiring 366 Touch sensor 372 FPC
373 IC
400 Display 410 Pixel 451 Opening

Claims (13)

A display device having a first housing, a second housing, a first display area, and a second display area,
The first display area has an area overlapping the first housing;
The second display area has an area overlapping the second housing;
The first casing is connected to the second casing via a hinge portion,
Each of the first display area and the second display area has a first display element,
The second display area further includes a second display element,
The first display element has a function of reflecting visible light;
The second display element is a display device having a function of emitting visible light. A display device having a first housing, a second housing, a first display area, a second display area, and a sensor,
The first display area has an area overlapping the first housing;
The second display area has an area overlapping the second housing;
The first casing is connected to the second casing via a hinge portion,
The sensor has a function of outputting a first signal;
The first display area and the second display area have a first display element and a second display element, respectively.
The first display element has a function of reflecting visible light;
The second display element has a function of emitting visible light;
A display device in which one of the first display area and the second display area displays on a first display element when the sensor outputs the first signal. 3. The display device according to claim 2, wherein the sensor has a function of outputting the first signal when an angle formed between the first housing and the second housing is equal to or smaller than the first angle. . In any one of Claims 1 thru | or 3,
The first casing is provided with a first display panel,
The second housing is provided with a second display panel,
The first display panel is the first display area;
The display device in which the second display panel is the second display area. In any one of Claims 1 thru | or 3,
The first housing and the second housing are provided with flexible display panels,
The flexible display panel has a first region and a second region;
The first area of the flexible display panel is the first display area,
A display device in which a second region of the flexible display panel is the second display region. A display device having a housing, a first display area, a second display area, and a sensor,
The housing has flexibility,
The first display area and the second display area are provided in the housing,
The sensor has a function of outputting a first signal;
The first display area and the second display area have a first display element and a second display element, respectively.
The first display element has a function of reflecting visible light;
The second display element has a function of emitting visible light;
A display device in which one of the first display area and the second display area displays on a first display element when the sensor outputs the first signal. The display device according to claim 6, wherein the sensor has a function of outputting the first signal when an angle formed by the first side of the housing is equal to or smaller than the first angle. In claim 6 or 7,
The housing is provided with a first display panel and a second display panel,
The first display panel is the first display area;
The display device in which the second display panel is the second display area. In any one of Claims 6 thru | or 8,
The housing is provided with a flexible display panel,
The flexible display panel has a first region and a second region;
The first area of the flexible display panel is the first display area,
A display device in which a second region of the flexible display panel is the second display region. In any one of Claims 1 thru | or 9,
The display device in which the first display element is a reflective liquid crystal element. In any one of Claims 1 thru | or 10,
The display device, wherein the second display element is a light emitting element. In any one of Claims 1 thru | or 11,
The display device in which the first display region and the second display region include a transistor including a metal oxide in a semiconductor layer in which a channel is formed. A display device according to any one of claims 1 to 12, comprising:
An electronic device including a touch sensor at a position overlapping at least one of the first display area and the second display area.

Images