JP2022121424A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device with high visibility.

SOLUTION: A display device includes a first substrate, a second substrate, a first display element, a second display element, and an input device. The first substrate includes a part of the first display element and the second display element. The second substrate includes the input device. The first display element and the second display element are provided between a first surface of the first substrate and a first surface of the second substrate. The first display element has a function of reflecting visible light. The second display element has a function of emitting visible light. A second surface of the second substrate, which is opposite to the first surface, includes an anti-reflection layer.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

There is an application for exception to loss of novelty

The present invention relates to an article, method or method of manufacture. Alternatively, the invention relates to a process, machine, manufacture or composition of matter. In particular, one embodiment of the present invention relates to semiconductor devices, light-emitting devices, display devices, electronic devices, lighting devices, driving methods thereof, or manufacturing methods 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, which includes a display device capable of displaying images on a curved surface.

Note that in this specification and the like, a semiconductor device refers to all devices that can function by utilizing semiconductor characteristics. A transistor, a semiconductor circuit, an arithmetic device, a memory device, or the like is one mode of a semiconductor device. Light-emitting devices, display devices, electronic devices, lighting devices, and electronic devices may include semiconductor devices.

In recent years, electronic devices such as smart phones and tablet terminals have become widely used, and opportunities to use information communication outdoors are increasing. In addition, in the field of display devices provided in electronic devices, there is competition for the development of low power consumption technology that enables long-term operation with a battery of limited capacity. For example, Patent Document 1 discloses a low power consumption liquid crystal display device in which an image signal is held for a long time by using a transistor including an oxide semiconductor with low off-state current for a pixel.

JP 2011-141522 A

2. Description of the Related Art Transmissive liquid crystal elements using a backlight as a light source, self-luminous organic EL elements, and the like are often used in display devices provided in electronic devices. These display elements have good visibility indoors, but under strong light such as outdoors on a clear day, the reflection of external light on the display surface is strong. diminished sexuality.

Therefore, it is preferable to use a reflective display element that utilizes reflection of external light under strong light. For example, in a display device using a reflective liquid crystal element, visibility improves as the intensity of outside light increases. However, since the display surface of the display device uses a glass substrate or a resin substrate having a reflectance of several percent, reflection of external light affects the display.

In addition, the reflective display element does not have sufficient visibility indoors where the intensity of outside light is weak.

Therefore, an object of one embodiment of the present invention is to provide a display device with good visibility even under strong light. Another object is to provide a display device including a display element having a function of emitting visible light and a display element having a function of reflecting visible light. Another object is to provide a display system with low power consumption. Another object is to provide a novel display device. Another object is to provide a novel electronic device.

The description of these problems does not preclude the existence of other problems. One aspect of the present invention does not need to solve all of these problems. Further, problems other than the above are naturally clarified from the description of the specification or the like, and it is possible to extract problems other than the above from the description of the specification or the like.

One embodiment of the present invention relates to a display device having a function of emitting visible light, a display device having a function of reflecting visible light, or a display device having a function of emitting visible light and a function of reflecting visible light. The present invention also relates to an electronic device having the display device. More details are as follows.

One embodiment of the present invention is a display device including a first substrate, a second substrate, a first display element, a second display element, and an input device, wherein the first substrate , a portion of the first display element, and a second display element, the second substrate having an input device, the first display element and the second display element being a portion of the first substrate. Provided between the first surface and the first surface of the second substrate, the first display element has a function of reflecting visible light, and the second display element has a function of emitting visible light has
The display device includes an antireflection layer provided on a second surface of the second substrate that faces the first surface.

In the above aspect, the first display element and the second display element are preferably provided in the same pixel unit.

Further, in the above aspect, a driver circuit is further provided, and the driver circuit is provided for driving the first display element and the second display element.
and a function to drive the display element and the input device.

Further, in the above aspect, the first display element has a liquid crystal material, and the second display element has an E
It is preferred to have the L material and the liquid crystal material to have a dichroic dye.

Moreover, in the above aspect, the antireflection layer preferably has a convex portion.

Further, in the above mode, it is preferable to have one or more selected from a light diffusion plate, a polarizing plate, and a colored film between the first display element and the input device.

Further, in the above aspect, the first display element and the second display element are each independently
A semiconductor layer in which a channel is formed is preferably electrically connected to a transistor including a metal oxide.

Another aspect of the present invention is an electronic device including any one of the display devices described above, a housing, and a hinge, wherein the housing and the hinge can accommodate the display device. It is an electronic device having a region.

In this specification, a connector such as FPC (Flexible
printed circuit) or TCP (Tape Carrier Pa
ckage), a module with a printed wiring board on top of the TCP, or a module with an IC (integrated circuit) mounted directly on a board with a display element formed by the COG (Chip On Glass) method. It may be included in the display device.

By using one embodiment of the present invention, a display device with good visibility even under strong light can be provided. Alternatively, a display device including a display element having a function of emitting visible light and a display element having a function of reflecting visible light can be provided. Alternatively, a display system with low power consumption can be provided. Alternatively, a novel display device can be provided. Alternatively, a novel electronic device can be provided.

Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Effects other than these are self-evident from the descriptions of the specification, drawings, claims, etc., and it is possible to extract effects other than these from the descriptions of the specification, drawings, claims, etc. is.

4A and 4B illustrate a display device; The figure explaining an antireflection layer. 4A and 4B illustrate a display device; 4A and 4B are diagrams for explaining a configuration of a touch sensor; FIG. 4A and 4B are diagrams for explaining a configuration of a touch sensor; FIG. FIG. 4 is a diagram for explaining an example of connection between a driver circuit and an FPC; The figure explaining an idling stop drive. 4A and 4B illustrate a method for manufacturing a display device; 4A and 4B illustrate a method for manufacturing a display device; 4A and 4B illustrate a method for manufacturing a display device; 4A and 4B illustrate a method for manufacturing a display device; 4A and 4B illustrate a method for manufacturing a display device; 4A and 4B illustrate a method for manufacturing a display device; 4A and 4B illustrate a method for manufacturing a display device; 4A and 4B illustrate a method for manufacturing a display device; 4A and 4B are diagrams for explaining a pixel unit; FIG. 4A and 4B are diagrams for explaining a pixel unit; FIG. 1A and 1B are a diagram illustrating a circuit of a display device and a top view of a pixel; 4A and 4B illustrate a circuit of a display device; 1A and 1B are a diagram illustrating a circuit of a display device and a top view of a pixel; 4A and 4B illustrate the structure of a display device; 4A and 4B illustrate the structure of a display device; Schematic diagram of the structure of a metal oxide. FIG. 4 is a diagram for explaining measurement results of XRD spectra of samples; 4A and 4B are TEM images of samples and diagrams for explaining electron beam diffraction patterns; FIG. The figure explaining the EDX mapping of a sample. 4A and 4B are diagrams for explaining the operation of a liquid crystal element; 4A and 4B illustrate a transistor; 4A and 4B illustrate a transistor; 4A and 4B illustrate a transistor; 4A and 4B illustrate a transistor; 4A and 4B illustrate a transistor; 4A and 4B illustrate a transistor; 4A and 4B illustrate a transistor; 4A and 4B are diagrams for explaining a configuration example of a display module; FIG. 1A and 1B are diagrams for explaining an electronic device; 1A and 1B are diagrams for explaining an electronic device; 1A and 1B are diagrams for explaining an electronic device; 1A and 1B are diagrams for explaining an electronic device; 1A and 1B are diagrams for explaining an electronic device;

Embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and those skilled in the art will readily understand that various changes can be made in form and detail without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the descriptions of the embodiments shown below.

In the configuration of the invention described below, the same reference numerals are used in common for the same parts or parts having similar functions in different drawings, and repeated description thereof will be omitted. Moreover, when referring to similar functions, the hatch patterns may be the same and no particular reference numerals may be attached.

In each drawing described in this specification, the size, layer thickness, or region of each configuration is
May be exaggerated for clarity. Therefore, it is not necessarily limited to that scale.

Note that ordinal numbers such as “first” and “second” in this specification and the like are used to avoid confusion of constituent elements, and are not numerically limited.

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

<1-1. Configuration Example 1 of Display Device>
A display device of one embodiment of the present invention includes a first substrate, a second substrate, a first display element, and a second substrate.
, an input device, and a drive circuit.

The first display element has a function of reflecting visible light, and the second display element has a function of emitting visible light. Therefore, display with low power consumption and good visibility can be performed by operating the first display element under strong light and operating the second display element under weak light.

A first display element, a second display element and an input device are provided between the first surface of the first substrate and the first surface of the second substrate. An antireflection layer is provided on the second surface of the second substrate, which faces the first surface. Therefore, the external light reflection on the display surface can be sufficiently suppressed under strong light,
Furthermore, visibility can be improved.

FIG. 1A illustrates a display device of one embodiment of the present invention. A display device 10 illustrated in FIG. 1A includes a first substrate 11, a second substrate 12, a layer 20, a driver circuit 30, and an FPC.
31 and FPC 32 .

A glass substrate, for example, can be used for the first substrate 11 and the second substrate 12 .
Alternatively, a flexible resin substrate may be used. In addition, in the display device 10, the second substrate 1
Since the second side is the display side (visible side), at least the second substrate 12 is made of a material having translucency.

Moreover, both the first surface and the second surface of the second substrate 12, or on the second surface, the antireflection layer 1
3 is provided. The antireflection layer 13 can have a structure shown in FIGS. 2A to 2F, for example.

FIG. 2A shows an example in which a light-transmitting dielectric layer 13a is provided on the second surface of the second substrate 12, which is the top surface of the display device 10. FIG. By providing a multilayer dielectric layer having an appropriate thickness as the dielectric layer 13a, it is possible to suppress reflected light due to the light interference effect. The reflectance of one side of the glass substrate is about 4 to 5%, but the second side of the second substrate 12 has a dielectric layer 13a having translucency.
is provided, the reflectance can be suppressed to about 0.05 to 0.5%.

Further, as shown in FIG. 2B, by providing a dielectric layer 13b having a light-transmitting property also on the first surface of the second substrate 12, the reflectance on the back side of the glass substrate can be suppressed. . in this case,
The reflectance on the front and back of the second substrate 12 can be suppressed to about 0.1 to 1.0%. Therefore, reflection of external light can be suppressed, and visibility of display can be improved.

Alternatively, as shown in FIG. 2C, an anti-glare pattern 13 formed of fine projections
c may be provided on the second surface of the second substrate 12 . Reflected light can be scattered by the anti-glare pattern 13c, and display by the reflective display element can be made easier to see. In addition, dirt such as fingerprints can be made less likely to adhere. In addition, in FIG. 2C, the second substrate 1
2 shows an example in which the second surface of 2 is processed to provide an anti-glare pattern 13c.
), a film 13d having an antiglare pattern formed thereon may be attached to the second surface of the second substrate 12. As shown in FIG.

The fine projections provided on the anti-glare pattern 13c include, for example, silicon,
Silica particles containing oxygen may be used. The particle size of the silica particles is 1 μm or more and 100 μm or less, preferably 3 μm or more and 50 μm or less.

Alternatively, as shown in FIG. 2E, the anti-glare pattern 13c and the dielectric layer 13b may be combined. Alternatively, as shown in FIG. 2(F), a film 13d having an anti-glare pattern and a dielectric layer 13b may be combined.

Returning to the description of FIGS. 1A and 1B. Between the first substrate 11 and the second substrate 12,
A layer 20 is provided. The layer 20 will be described with reference to FIG. 1(B). FIG. 1(B) corresponds to an enlarged cross-sectional view taken along line X1-X2 shown in FIG. 1(A). Layer 20 includes device layer 21 , device layer 22 , input device 25 and adhesion layer 26 .

The device layer 21 has an FET layer 21a, an LC layer 21b, an LC layer 21b_LC and an OLED layer 21c. The FET layer 21a has transistors and the like that constitute a pixel circuit. LC
The layer 21b comprises part of the first display element and the LC layer 21b_LC comprises the other part of the first display element. Note that the first display element is composed of the LC layer 21b and the LC layer 21b_LC. The OLED layer 21c has a second display element. the first display element and the second
is electrically connected to a transistor included in the FET layer 21a.

As the first display element, for example, a reflective liquid crystal element can be used. Also, the second
As the display element, for example, a light emitting element can be used. A reflective liquid crystal element consumes less power and can display images with high visibility even under sunlight on a sunny day. The light-emitting element can perform display with high visibility under indoor light or outdoors in cloudy weather.

Further, as a reflective liquid crystal element, it is preferable to drive using a guest-host liquid crystal mode. By using the guest-host liquid crystal mode, a reflective display element can be provided without using a polarizing plate. Since no polarizing plate is used, the display of the liquid crystal device can be brightened. However, the reflective liquid crystal element of one embodiment of the present invention is not limited to the guest-host liquid crystal mode, and may be a TN (Twisted Nematic) mode, an OCB (Optical
fully compensated birefringence) mode, vertical alignment (V
It may be driven using a driving method such as A) mode.

Note that with the structures shown in FIGS. 1A and 1B, a display device capable of displaying images with high visibility can be provided regardless of the intensity of external light. In particular, the display device has good visibility even under strong light and can be operated with low power consumption.

Further, the display device 10 shown in FIGS. 1A and 1B includes an antireflection layer 13 and
It has a configuration in which an input device 25 and an element layer 22 are provided. With this structure, the second substrate 12 can be manufactured through relatively simple steps. Therefore, manufacturing costs can be reduced. Further, by using a thin film substrate (for example, less than 0.7 mm, preferably 0.1 mm or more and 0.5 mm or less, more preferably 0.1 mm or more and 0.3 mm or less) as the second substrate 12, the second substrate 12 A step of thinning the substrate 12, typically a polishing step, can be eliminated. By reducing the polishing process, the yield of the display device 10 can be increased.

As the input device 25, for example, a capacitive touch sensor can be used. The input device 25 is provided so as to overlap the display section, and has a function of converting a user's touch operation on the display section into an electric signal and outputting the electric signal.

The input device 25 can be provided on the first surface of the second substrate 12 . Alternatively, it may be provided on the dielectric layer 13b described above. As a capacitive touch sensor, a light-transmitting conductive film can be used as wiring and electrodes, but it is preferable to use a metal mesh that has a lower resistance and can be applied to a large display device. Although metal is generally a material with high reflectance, it can be made darker by subjecting it to an oxidation treatment or the like. Therefore, even when the display device is viewed from the second substrate side, deterioration in visibility due to reflection of external light can be suppressed.

FIG. 4 is a diagram showing an example of a capacitive touch sensor provided on a substrate, with a part thereof being enlarged. FIG. 5A is a top view of the touch sensor, which includes a proximity sensor. FIG. 5B is a cross-sectional view taken along the line X3-X4 shown in FIG. 5A. Note that the substrate provided with the touch sensor can be the second substrate 12 shown in FIG. 1 and the like.

An insulating film 501B shown in FIG. 5B corresponds to the adhesive layer 26 shown in FIG. 1 and the like. Also, the insulating film 572 has a region sandwiched between the insulating film 501B and the proximity sensor 575 .

Detect changes in capacitance, illuminance, magnetic force, radio waves, pressure, etc. caused by nearby objects,
A sensing element that provides a signal based on a sensed physical quantity can be used in the proximity sensor 575 .

For example, a conductive film, a photoelectric conversion element, a magnetic sensing element, a piezoelectric element, a resonator, or the like can be used as the sensing element.

For example, the proximity sensor 575 can be a sensing circuit capable of providing a signal that varies based on the parasitic capacitance of the conductive film. A control signal can be supplied to the first electrode, and the potential or current of the second electrode, which changes based on the supplied control signal and capacitance, can be sensed and supplied as a sensing signal. Accordingly, it is possible to detect a finger or the like that is close to the conductive film in the air by using the change in capacitance.

For example, the first electrode C1(g) and the second electrode C2(h) can be used for the proximity sensor 575 (see FIGS. 4 and 5A). Note that the second electrode C2(h) has a portion that does not overlap with the first electrode C1(g). Also, g and h are natural numbers of 1 or more.

Specifically, a first electrode C1(g) electrically connected to a control line CL(g) extending in the row direction (the direction of an arrow indicated by R in the drawing) and a first electrode C1(g) intersecting the row direction. a second electrode C2(h) electrically connected to the signal line ML(h) extending in the column direction (the direction of the arrow indicated by C in the figure),
It can be used for proximity sensor 575 .

For example, a conductive film having a light-transmitting region in a region overlapping with a pixel is formed on the first electrode C1 (g).
Alternatively, it can be used for the second electrode C2(h).

For example, a mesh-like conductive film having openings 576 in regions overlapping with pixels may be used as the first electrode C.
1(g) or second electrode C2(h).

The control line CL(g) has a wiring BR(g,h). The control line CL(g) is connected to the wiring BR(g
, h) cross the signal line ML(h) (see FIG. 5B).

For example, the laminated film is formed of a first electrode C1(g), a second electrode C2(h), a control line CL(g),
It can be used for the signal line ML(h) and the wiring BR(g, h). For example, the conductive film C
A laminated film in which a conductive film CL(g)A and a dark film CL(g)B are laminated such that L(g)A is sandwiched between the dark film CL(g)B and the pixel can be used.

Here, a film having a lower reflectance to visible light than the conductive film CL(g)A is referred to as a dark film CL(g).
B is preferred.

In addition, a conductive film BR(g, h)A and a dark film BR(g, h) are connected to the wiring BR(g, h).
A laminated film in which B is laminated can be used. The reflectance for visible light is the conductive film BR (g, h
) A is preferably used for the dark film BR(g,h)B.

Thereby, the reflection of visible light from the first electrode C1(g), the second electrode C2(h), the control line CL(g), the signal line ML(h), and the wiring BR(g, h) can be weakened. can be done. As a result, the display on the display section can be highlighted and a good display can be obtained.

For example, the following materials can be used for the conductive film CL(g)A and the conductive film BR(g,h)A.

A film containing copper oxide, a film containing copper chloride, tellurium chloride, or nickel oxide is treated as a dark film CL (
g) Can be used for B and dark film BR(g,h)B. Also, the dark film CL(g)B
and the dark film BR(g,h)B is composed of Ag particles, Ag fibers, metal fine particles such as Cu particles, carbon nanotubes (CNT), nano carbon particles such as graphene, or PEDOT,
It may be formed using a conductive polymer such as polyaniline or polypyrrole.

The proximity sensor 575 also includes an insulating film 571 between the wiring BR(g,h) and the signal line ML(h). This can prevent a short circuit between the wiring BR(g,h) and the signal line ML(h).

Returning to the description of FIGS. 1A and 1B. The input device 25 is configured to overlap the first display element and the second display element. Since the input device 25 can be manufactured in processes different from those of the transistor, the first display element, and the second display element, the yield of each element can be improved.

The drive circuit 30 may have a function of controlling the input device 25 in addition to functioning as a source driver for supplying image data to the first display element and the second display element.
The drive circuit 30 can be provided by mounting an IC chip formed using a silicon wafer, for example. Alternatively, the driver circuit 30 may be formed using transistors provided over the first substrate 11 .

1(A) and 1(B) illustrate a form in which a bare chip is mounted by COG as the drive circuit 30, but it may be provided by using TCP or COF (Chip on Film).

The driving circuit 30 is electrically connected through the FPC 31 to a circuit for supplying image data and the like. Also, the input device 25 is electrically connected to the drive circuit 30 via the FPC 32 .

FIGS. 6A to 6D are diagrams for explaining electrical connections among the drive circuit 30, FPC 31 and FPC 32. FIG.

FIG. 6A shows an example in which the drive circuit 30 has a function as a source driver for supplying image data to the first display element and the second display element and a function for controlling the input device 25. FIG. At this time, the drive circuit 30 can be electrically connected to the FPC 31 through the wiring 33a. Also, the drive circuit 30 can be electrically connected to the FPC 32 via the wiring 33b.

FIG. 6B shows an example in which the drive circuit 30 is divided into two. Here, drive circuit 3
0a functions as a source driver that supplies image data to the first display element and the second display element. Further, the drive circuit 30b has a function of controlling the input device 25. FIG. At this time, the drive circuit 30a can be electrically connected to the FPC 31 through the wiring 33a. Also, the drive circuit 30b can be electrically connected to the FPC 32 via the wiring 33b.

Note that, as shown in FIG. 6C, the driving circuit 30a and the driving circuit 30b are connected to a wiring 33c.
may be electrically connected via Also, as shown in FIG. 6D, the FPC 31 and the FPC 32 may be electrically connected via a wiring 33d. With such a structure, wiring for supplying power supply voltage and signals can be reduced.

Returning to the description of FIGS. 1A and 1B. A transistor including a metal oxide in a channel region (hereinafter referred to as an OS transistor) is preferably used as the transistor provided in the FET layer 21a. An OS transistor has extremely low off-state current and can hold a potential written as image data for a long time. Therefore, so-called idling stop driving, in which image display can be maintained without newly writing image data in a plurality of frame periods, is possible.

In idling stop driving, image data written in pixels can be held for two frames or more. As a result, the frequency of rewriting image data can be reduced, and power consumption can be reduced.

Since a reflective liquid crystal element that can be used as the first display element does not require a backlight, the power consumption of the pixel portion is equal to the power consumption of circuit operation. Therefore, it is particularly preferable to drive the pixel having the first display element in idling stop mode, and the power consumption of the pixel portion can be reduced in proportion to the frequency of rewriting.

An example of the idling stop driving described above will be described with reference to FIGS.

FIG. 7A shows a circuit diagram of a pixel composed of a liquid crystal element 35 and a pixel circuit 36. FIG. In FIG. 7A, the transistor M1 connected to the signal line SL and the gate line GL,
A capacitive element Cs _LC and a liquid crystal element LC are shown.

FIG. 7B shows the signal line S in the normal drive mode that is not the idling stop drive.
4 is a timing chart showing waveforms of signals respectively applied to L and gate lines GL; In normal drive mode, it can be operated at a normal frame frequency (eg, 60 Hz).

Assuming that the periods of successive frames at the frame frequency _are T1, T2 _, and T3, scanning signals are applied to the gate lines in _each frame period, and the operation of writing the data _D1 of the signal line to the pixels is performed. This operation is even when writing the same data D ₁ in T ₁ , T ₂ and T ₃ .
The same is true even when writing different data.

FIG. 7C is a timing chart showing waveforms of signals respectively applied to the signal line SL and the gate line GL in idling stop driving. The idling stop drive can be operated at a low frame frequency (eg, 1 Hz).

In FIG. 7C, the frame period at the frame frequency is T ₁ , the data writing period is T _W , and the data holding period is T _RET . In the idling stop driving, a scanning signal is applied to the gate line during the period _{TW, the data D1 of the signal line is written in the pixel, and the gate line is fixed at a low level voltage during the period TRET , and} the transistor M1 is turned off. An operation of holding the _once written data D1 in the pixel is performed.

Here, by using an OS transistor as the transistor M1, the data D1 can be held for _a long time due to its low off-state current. Also, although FIGS. 7A to 7C show an example using the liquid crystal element LC, the idling stop driving can be similarly performed by using a light emitting element such as an organic EL element.

Note that in the circuit diagram shown in FIG. 7A, the liquid crystal element LC is _a leak path for the data D1. Therefore, it is preferable that the resistivity of the liquid crystal element LC is set to 1.0×10 ¹⁴ Ω·cm or more in order to perform idling stop driving appropriately.

Examples of metal oxides used in the above-described transistors include CAC-OS (
Cloud-Aligned Composite-Oxide Semiconductor
tor) and the like can be used.

In particular, it is preferable to use an oxide semiconductor having a wider bandgap than silicon.
A semiconductor material with a wider bandgap and lower carrier density than silicon can reduce the current in the off-state of a transistor.

In addition, due to the low off-state current, charge accumulated in the capacitor through the transistor can be held for a long time. By applying such a transistor to a pixel, it is possible to stop the driving circuit 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.

Further, a polycrystalline semiconductor may be used for the above-described pixel and a semiconductor device such as a transistor used in a circuit for driving the pixel. For example, it is preferable to use polycrystalline silicon or the like. Polycrystalline silicon can be formed at a lower temperature than monocrystalline 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. Moreover, even when an extremely large number of pixels are provided, the gate driver circuit and the source driver circuit can be formed on the same substrate as the pixels, so that the number of parts constituting the electronic device can be reduced.

By using the above structure, it is possible to provide a display device capable of displaying images with high visibility regardless of the intensity of external light. In particular, the display device has favorable visibility even under strong light and can operate with low power consumption.

<1-2. Configuration Example 2 of Display Device>
In addition, in the display device 10 shown in FIGS. 1A and 1B, one mode of the layer 20 provided between the first substrate 11 and the second substrate 12 is illustrated, but the present invention is not limited to this. For example, layer 20 may be configured as shown in FIG.

FIG. 3 corresponds to an enlarged cross-sectional view taken along line X1-X2 shown in FIG. 1(A), which is different from the enlarged view shown in FIG. 1(B).

The layer 20 shown in FIG. 3 has an element layer 21, an element layer 22, a light diffusion plate 23, an input device 25, and adhesive layers 26 and 26a. Note that the structure of the layer 20 shown in FIG. 1B, the light diffusion plate 23,
The configuration of the input device 25 is different from that of the adhesive layer 26a. For other configurations, see Fig. 1(B).
is the same as the configuration shown in , and the same effect is achieved.

The light diffusion plate 23 has a function of diffusing light reflected by the reflective electrode of the liquid crystal element. This function enables natural color development even in a reflective liquid crystal element. In addition, it is possible to display a white color close to white paper.

Further, the input device 25 shown in FIG. 3 has an input device 25a and a polarizing plate 25b. The input device 25a may have the same configuration as the input device 25 described above.

A circularly polarizing plate, for example, can be used as the polarizing plate 25b. Display using reflected light can be performed by using a circularly polarizing plate and a change in deflection angle by the liquid crystal.

Note that the position where the polarizing plate 25b is provided is not limited to the configuration shown in FIG. For example, it may be provided between the input device 25 a and the light diffusion plate 23 or between the light diffusion plate 23 and the element layer 22 .

The adhesive layer 26 a may have the same configuration as the adhesive layer 26 .

This embodiment can be implemented by appropriately combining at least part of it with other embodiments described herein.

(Embodiment 2)
In this embodiment, a method for manufacturing an input device included in a display device of one embodiment of the present invention is described.
Description will be made with reference to FIGS. 8 to 15. FIG. Here, a case where a capacitive touch sensor is applied as an input device will be described.

<2-1. Production method 1>
First, an example of a manufacturing method of one embodiment of the present invention is described with reference to FIGS.

First, substrate 161 is prepared. Substrate 161 preferably has a relatively flat surface. As the substrate 161, in addition to a glass substrate or a resin substrate, a non-light-transmitting substrate such as a metal substrate or a ceramic substrate can be used. Next, a separation layer 162, a layer to be separated 163, and an insulating layer 164 are stacked over the substrate 161 (see FIG. 8A).

For the peeling layer 162 and the layer to be peeled 163, a combination of materials that can be peeled at their interface is used. It is preferable to use a metal or a metal oxide as the peeling layer 162 and use a resin material such as polyimide as the layer 163 to be peeled. By changing the adhesiveness between the two, it is possible to make a configuration in which they can be peeled off.

Examples of materials that can be used for the release layer 162 include various metals such as titanium, molybdenum, aluminum, tungsten, and tantalum, or alloys.

As a material that can be used for the separation layer 162, oxides of various metals can be used. Examples include titanium oxide, molybdenum oxide, aluminum oxide, tungsten oxide, indium tin oxide, indium zinc oxide, and In--Ga--Zn oxide. In particular, it is preferable to use titanium or titanium oxide as the separation layer 162 .

Alternatively, a metal such as tungsten is used as the separation layer 162 and an oxide such as silicon oxide is used as the layer 163 to be separated. At this time, the surface of the metal is oxidized by contact with the oxide to form an oxide of the metal (eg, tungsten oxide). Note that heat treatment may be performed after the layer 163 to be peeled is formed to accelerate the oxidation reaction. Here, by applying an external force that physically separates the separation layer 162 , separation can be performed at the interface between the separation layer 162 and the layer to be separated 163 .

In this embodiment mode, titanium oxide is used as the separation layer 162 and polyimide is used as the layer 163 to be separated. The thickness of the layer 163 to be peeled is preferably 10 μm or less, more preferably 0.1 μm or more and 5 μm or less, and still more preferably 0.5 μm or more and 3 μm or less.
By setting the thickness of the layer to be peeled 163 within the above range, the layer to be peeled 163 can be preferably removed after separation at the interface between the layer 162 and the layer to be peeled 163 . Note that the removal includes, for example, an oxygen plasma treatment, a wet etching treatment using a chemical solution, or the like.

An insulating film having a property of transmitting visible light can be used for the insulating layer 164 . For example, in addition to inorganic insulating films such as silicon oxide, silicon nitride, and aluminum oxide, organic insulating films such as resin can also be used.

Next, an opening 165 reaching the layer 163 to be peeled is formed in the insulating layer 164 (see FIG. 8B).

By providing the opening 165, a connection portion for electrically connecting the touch sensor to the outside can be provided.

Next, over the insulating layer 164, a conductive layer 179a, a conductive layer 179b, an insulating layer 180, and a light shielding layer 18 are formed.
1. A colored layer 182, an insulating layer 183, and a conductive layer 170 are formed (see FIG. 8C).

Note that the conductive layer 179a, the conductive layer 179b, the insulating layer 180, the light-blocking layer 181, and the colored layer 182
, and the insulating layer 183 correspond to the element layer 22 shown in FIG.

The conductive layer 179a functions as a pixel electrode, and the conductive layer 179b functions as a connection electrode. As the conductive layers 179a and 179b, a conductive film that transmits visible light, such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and In--Sn--Si oxide, may be used.

The insulating layer 180 is made of an inorganic material, an organic material, or the like. Examples of inorganic materials include silicon oxide, silicon oxynitride, and silicon nitride. Examples of organic materials include acrylic resins and polyimides.

As the light shielding layer 181, a material that suppresses transmission of light can be used. This will
A light shielding layer 181 can be used for a black matrix. Specifically, a resin containing pigments or dyes can be used for the light shielding layer 181 . For example, a resin in which carbon black is dispersed can be used for the light shielding film. Alternatively, an inorganic compound, an inorganic oxide, a composite oxide containing a solid solution of a plurality of inorganic oxides, or the like can be used for the light shielding layer 181 . Specifically, a black chromium film, a film containing cupric oxide, or a film containing copper chloride or tellurium chloride can be used as the light shielding layer 181 .

A material that transmits light of a predetermined color can be used for the colored layer 182 . Accordingly, the colored layer 182 can be used as a color filter.

For example, a material that transmits blue light, a material that transmits green light, or a material that transmits red light can be used for the colored layer 182 . As a result, the width of the spectrum of light transmitted through the colored layer 182 can be narrowed, and the display can be made vivid.

Further, for example, a material that absorbs blue light, a material that absorbs green light, or a material that absorbs red light can be used for the colored layer 182 . Specifically, a material that transmits yellow light, a material that transmits magenta light, or a material that transmits cyan light is used as the colored layer 182 .
can be used for Thereby, the width of the spectrum of light absorbed by the colored layer 182 can be narrowed, and the display can be brightened.

A material similar to that of the insulating layer 180 may be used for the insulating layer 183 .

A metal layer such as copper or nickel is preferably used as the conductive layer 170 . After a conductive film is formed, the conductive layer 170 is processed to form a vertical wiring and a horizontal wiring to form an island shape. Part of the conductive layer 170 is provided so as to extend and be in contact with the conductive layer 179b.

Next, the surface of the conductive layer 170 is oxidized to form a dark layer 171b, a dark layer 172b, and a dark layer 173b (see FIG. 8D).

Oxygen plasma treatment or the like can be used for the oxidation treatment. By forming the dark layer 171b, the dark layer 172b, and the dark layer 173b, the reflectance of the conductive layer 170 can be reduced. The dark layer 171b, the dark layer 172b, and the dark layer 173b are
In some cases, it does not exhibit sufficient conductivity. In addition, the conductive layer 17 is not oxidized by the oxidation treatment.
The conductive layers 171a, 172a, and 173a are the regions where the conductivity equal to 0 is left.

Note that a conductive layer including the conductive layer 171 a and the dark layer 171 b is the wiring 171 . A conductive layer including the conductive layer 172 a and the dark layer 172 b is used as the wiring 172 . A conductive layer including the conductive layer 173 a and the dark layer 173 b is used as the wiring 173 .

Next, an insulating layer 166 is formed over the wirings 171 , 172 and 173 . The insulating layer 166 can be formed using the same material as the layer 163 to be separated. After that, a wiring 174 that electrically connects the wiring 171 and the wiring 173 is formed (see FIG. 8E).

Note that the wirings 171, 172, 173, the insulating layer 166, and the wiring 174 correspond to the input device 25 shown in FIG.

The wiring 174 can be formed through a step of providing a conductive layer in openings provided in the insulating layer 166, the dark layers 171b, and 173b, a process of processing into a desired shape, and a process of oxidation treatment. Similarly to the wiring 171 and the like, the wiring 174 has a conductive layer 174a and a conductive layer 174b provided by oxidation treatment. By providing the opening in the dark layer 171b, the conductive layer 174a and the conductive layer 171a can be electrically connected. Further, by providing an opening in the dark layer 173b, the conductive layer 174a and the conductive layer 173a can be electrically connected.

Next, a substrate 168 is attached over the insulating layer 166 and the wiring 174 with an adhesive layer 187 interposed therebetween (see FIG. 9A).

Here, the substrate 168 corresponds to the second substrate 12 shown in FIGS.

Next, the processing region (the region including the peeling layer 162 and the layer to be peeled 163) is irradiated with light from the substrate 161 side (see FIG. 9B).

The light irradiation heats the peeling layer 162, the layer to be peeled 163, and the interface between them, which causes structural changes, which can reduce adhesion between them.

For example, short-wavelength laser light can be used as the light to be irradiated here. Typically, an excimer laser capable of emitting light with a wavelength of 351 nm to 353 nm (XeF), 308 nm (XeCl), or the like can be used. Alternatively, double wave (515 nm, 532 nm, etc.) or triple wave (343 nm, 355 nm, etc.) of solid-state laser (YAG laser, fiber laser, etc.)
nm, etc.) may be used.

Here, it is preferable that the laser light be a linear beam. By moving the workpiece horizontally in the minor axis direction of the linear beam while irradiating the linear beam, the entire surface of the workpiece can be efficiently irradiated with the laser.

Next, separation is performed at or near the interface between the separation layer 162 and the layer to be separated 163 (FIG. 9 (
C)).

For example, the separation can be performed by fixing the substrate 161 with a suction stage or the like and applying a physical force to move the substrate 168 side upward.

Next, the layer to be peeled 163 is removed by ashing, and the insulating layer 164 and the opening 1 are removed.
The conductive layer 179b formed in 65 is exposed (see FIG. 9D).

Through the above steps, the element layer 22 and the input device 25 can be formed on one surface of the substrate 168 .

Next, a process of bonding the element layer 21, the element layer 22, and the input device 25 shown in FIGS. 1A and 1B will be described with reference to FIGS. In addition, FIG.
1A to 1C correspond to cross-sectional process diagrams taken along line X1-X2 in FIG. 1A.

First, the element layer 21 is provided over the first substrate 11 (see FIG. 10A).

A wiring 33 b is provided on the first substrate 11 .

Next, the element layer 21 and the substrate 168 provided with the element layer 22 and the input device 25 are bonded together. Also, the substrate 11 and the insulating layer 164 formed below the substrate 168 are sealed using the adhesive layer 26 . After that, an LC layer 21b_LC is formed between the LC layer 21b and the insulating layer 164.
is formed (see FIG. 10(B)).

Next, the drive circuit 30 is mounted so as to be electrically connected to the wiring 33b provided on the substrate 11. Next, as shown in FIG. After that, the conductive layer 173 of the wiring 173 of the touch sensor functioning as the input device 25 is formed.
The conductive layer 179b electrically connected to a and the wiring 33b are electrically connected using the FPC 32 (see FIG. 10C).

Through the above steps, the display device 10 shown in FIGS. 1A and 1B can be formed.

Note that although the structure in which the opening 165 reaching the layer 163 to be peeled is provided in the steps shown in FIGS. FIG. 11 shows an example of a configuration in which the opening 165 is not provided.

FIG. 11 is a cross-sectional view of a modification of the display device 10 shown in FIG. 10(C). In FIG. 11, conductive layers 179 a and 179 a and 179 a are formed on the layer 163 to be peeled without providing the insulating layer 164 and the opening 165 .
79b is provided. After that, the separation layer 162 and the layer 163 to be separated are separated, and the layer 163 to be separated is removed, whereby the display device 10 can be formed. In the case of the structure shown in FIG. 11, the LC layer 21b and the conductive layer 179a functioning as a pixel electrode are in contact with each other.

<2-2. Production method 2>
Next, <2-1. 12 to 1 for a mode different from the manufacturing method shown in Manufacturing Method 1>
5 will be used for explanation. 12 to 15 are cross-sectional views explaining a method of manufacturing the display device 10 shown in FIG.

First, the substrate 161a is prepared. Next, a separation layer 162a, a layer to be separated 163a, and an insulating layer 164a are formed over the substrate 161a (see FIG. 12A).

The substrate 161a, the separation layer 162a, the layer to be separated 163a, and the insulating layer 164a can be formed by a method similar to that of the substrate 161, the separation layer 162, the layer to be separated 163, and the insulating layer 164 described above.

Next, a conductive layer 179, an insulating layer 180a, a light shielding layer 181a, and a colored layer 1 are formed on the insulating layer 164a.
82a and an insulating layer 183a are formed (see FIG. 12B).

Note that the conductive layer 179, the insulating layer 180a, the light-shielding layer 181a, and the colored layer 1 over the insulating layer 164a
82a and the insulating layer 183a correspond to the element layer 22 shown in FIG.

A conductive layer 179, an insulating layer 180a, a light shielding layer 181a, a colored layer 182a, and an insulating layer 183
a can be formed by the same method as the conductive layers 179a and 179b, the insulating layer 180, the light shielding layer 181, the colored layer 182, and the insulating layer 183 described above.

Next, an adhesive layer 184 and a light diffusion plate 185 are formed on the insulating layer 183a. The light diffusion plate 185 corresponds to the light diffusion plate 23 shown in FIG. 3, and the adhesive layer 184 corresponds to the adhesive layer 2 shown in FIG.
6a.

Next, the peeling layer 162a and the layer to be peeled 163a are separated (see FIGS. 12D and 12E).

The step of separating the peeling layer 162a and the layer to be peeled 163a can be performed by the same method as the step of separating the peeling layer 162a and the layer to be peeled 163a described above.

In addition, as shown in FIG. 12E, the element layer 22, the adhesive layer 26a, and the light diffusion plate 23 are formed in order.

Next, a substrate 161b is prepared. After that, a separation layer 162b, a layer to be separated 163b, and an insulating layer 164 are formed over the substrate 161b (see FIG. 13A).

Next, an opening 165 is formed in the insulating layer 164 (see FIG. 13B).

Next, a conductive layer 170, a wiring 171, a wiring 172, a wiring 173, an insulating layer 166, and a wiring 174 are formed over the insulating layer 164 (see FIGS. 13C, 13D, and 13E).

Note that the conductive layer 170, the wiring 171, the wiring 172, the wiring 173, the insulating layer 166, and the wiring 174 correspond to the input device 25a shown in FIG.

Next, the polarizing plate 167, the adhesive layer 169, and the substrate 16 are formed over the insulating layer 166 and the wiring 174.
8 is formed (see FIG. 14(A)).

The polarizing plate 167 corresponds to the polarizing plate 25b shown in FIG. As the polarizing plate 167, for example, a linear polarizing plate or a circular polarizing plate may be used. Especially in the case of a reflective liquid crystal element, a circularly polarizing plate can be preferably used. As a circularly polarizing plate, for example, a linearly polarizing plate and 1
A laminate of /4 wavelength retardation plates can be used. By using a circularly polarizing plate,
An effect of suitably suppressing external light reflection can be added.

Further, as the polarizing plate 167, an organic layer having a dichroic dye whose molecular long axes are aligned in a predetermined direction may be used. The organic layer has a function as a polarizer. In addition, it is preferable to use a liquid crystal material in order to align the major axes of the molecules of the dichroic dye in one predetermined direction. After aligning the long axes of the molecules in one predetermined direction with the liquid crystal material, the monomer added together with the dichroic dye may be cured and polymerized.

As the adhesive layer 169, various curable adhesives such as a photocurable adhesive such as an ultraviolet curable adhesive, a reactive curable adhesive, a thermosetting adhesive, and an anaerobic adhesive can be used. Details of materials that can be used for the adhesive layer 169 will be described later.

As the substrate 168, a thin film substrate to which antireflection treatment or antiglare treatment is applied may be used. Note that the substrate 168 corresponds to the second substrate 12 shown in FIGS.

Next, the peeling layer 162b and the layer to be peeled 163b are separated (see FIGS. 14B, 14C, and 14D).
reference).

The peeling layer 162b and the layer to be peeled 163b are separated by separating the peeling layer 162 described above,
It can be the same as the layer to be peeled 163 .

Elements corresponding to the input device 25 shown in FIG. 3 are formed below the substrate 168 shown in FIG. 14(D). In addition, as shown in FIG. 14D, a part of the input device 25 may include an adhesive layer 169 .

Next, the substrate 168 and the element layer 22 are bonded together using an adhesive layer 186 (FIG. 15 (
A)).

Note that the adhesive layer 186 is provided between the light diffusion plate 185 and the insulating layer 164 .

Next, the element layer 21 and the substrate 168 provided with the input device 25 and the element layer 22 are bonded together. Also, the substrate 11 and the insulating layer 164 formed below the substrate 168 form the adhesive layer 26 .
is sealed using After that, the LC layer 21b_L is formed between the LC layer 21b and the conductive layer 179.
C is formed (see FIG. 15B).

Next, the drive circuit 30 is mounted so as to be electrically connected to the wiring 33b provided on the substrate 11. Next, as shown in FIG. After that, the conductive layer 173 of the wiring 173 of the touch sensor functioning as the input device 25 is formed.
a and the wiring 33b are electrically connected using the FPC 32 (see FIG. 15C).

Through the above steps, the display device 10 shown in FIG. 3 can be formed.

This embodiment can be implemented by appropriately combining at least part of it with other embodiments described herein.

(Embodiment 3)
In this embodiment, a display device of one embodiment of the present invention and a method for driving the display device will be described.

<3-1. About the concept of the display device>
For example, a hybrid display can be preferably used as a display device of one embodiment of the present invention. Note that the hybrid display can perform hybrid display.

Hybrid display is a method of displaying characters or images on a single panel by using both reflected light and self-luminous light to complement each other in color tone or light intensity. Alternatively, the hybrid display is a method of displaying characters and/or images from a plurality of display elements in the same pixel or the same sub-pixel using respective lights. However, when looking locally at a hybrid display that performs hybrid display, a pixel or sub-pixel displayed using any one of a plurality of display elements and a display using two or more of the plurality of display elements pixels or sub-pixels.

In this specification and the like, a display that satisfies any one or more of the above configurations is referred to as a hybrid display.

Also, a hybrid display has a plurality of display elements in the same pixel or the same sub-pixel. Note that examples of the plurality of display elements include a reflective element that reflects light and a self-luminous element that emits light. Note that the reflective element and the self-luminous element can be controlled independently. A hybrid display has a function of displaying characters and/or images using either one or both of reflected light and self-luminescence in a display section.

A 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 can be provided with a second display element that emits visible light. Alternatively, it can have a pixel provided with a first display element and a second 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.

A display device has a function of displaying an image using one or both of first light reflected by a first display element and second light emitted by a second display element. Alternatively, the display device has a function of expressing 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. have

In addition, the display device includes a first pixel that expresses gradation by controlling the amount of reflected light from the first display element, and a second pixel that expresses gradation by controlling the amount of light emitted from the second display element. It is preferable to have a configuration having a second pixel to express. A plurality of the first pixels and the second pixels are arranged in a matrix, for example, and form a display section.

Moreover, it is preferable that the first pixels and the second pixels are arranged in the display area in the same number and at the same pitch. At this time, a combination of adjacent first pixels and second pixels can be called a pixel unit. Accordingly, as described later, an image displayed only with a plurality of first pixels, an image displayed only with a 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.

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

A reflective liquid crystal element can be typically used for the first display element. Alternatively, a shutter-type MEMS (Micro Electro Mechanism) is used as the first display element.
hanical Systems) elements, light interference type MEMS elements, and elements using microcapsule, electrophoresis, electrowetting, electronic liquid powder (registered trademark) methods, and the like can be used.

A second display element included in the second pixel has a light source, and an element that uses light from the light source for display can be used. In particular, it is preferable to use an electroluminescent element that can extract light from a light-emitting substance by applying an electric field. Since the brightness and chromaticity of the light emitted by such pixels are not affected by external light, they have high color reproducibility (wide color gamut) and high contrast, that is, vivid display. be able to.

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

The first pixel is, for example, a sub-pixel exhibiting white (W), or red (R), green (G
) and blue (B). Similarly, the second pixel is a sub-pixel exhibiting, for example, white (W), or red (R), for example.
A structure having sub-pixels emitting three colors of green (G) and blue (B) can be employed. Note that the sub-pixels included in each of the first pixel and the second pixel may have four or more colors. As the number of sub-pixel types increases, power consumption can be reduced and color reproducibility can be improved.

One aspect of the present invention provides a first mode of displaying an image with first pixels, a second mode of displaying an image with second pixels, and a mode of displaying an image with first pixels and second pixels. A third mode can be switched. Further, as shown in Embodiment 1, the first pixel and the second
It is also possible to display a composite image by inputting different image signals to each of the pixels.

A first mode is a mode in which an image is displayed using light reflected by the first display element.
Since the first mode does not require a light source, it is a drive mode with extremely low power consumption. for example,
This 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 reflected light is used, display that is easy on the eyes can be performed, and there is an effect that the eyes are less tired.

The second mode is a mode in which an image is displayed using light emitted by the second display element. Therefore, 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 low, such as at night or in a dark room. In addition, when the outside light is dark, the user may feel dazzled by bright display. In order to prevent this, it is preferable to perform display with suppressed luminance in the second mode. In addition to suppressing glare, power consumption can also be reduced. The second mode is suitable for displaying vivid images, smooth moving images, and the like.

The third mode is a mode in which display is performed using both reflected light from the first display element and light emission from the second display element. Specifically, the light emitted by the first pixel and the light emitted by the second pixel adjacent to the first pixel are mixed to drive to express one color. Power consumption can be suppressed more than in the second mode while displaying more vividly than in the first mode. For example, it is effective under indoor lighting, when the illuminance of outside light is relatively low, such as in the morning or evening, or when the chromaticity of outside light is not white.

<3-2. Configuration example of display device>
A more specific example of one embodiment of the present invention will be described below with reference to the drawings.

FIG. 16 illustrates the pixel array 40 included in the display device of one embodiment of the present invention. The pixel array 40 has a plurality of pixel units 45 arranged in a matrix. Pixel unit 45 has pixels 46 and pixels 47 .

In FIG. 16, pixels 46 and 47 are red (R), green (G), and blue (B), respectively.
) has display elements corresponding to three colors.

The pixel 46 includes a display element 46R corresponding to red (R) and a display element 46R corresponding to green (G).
It has a display element 46B corresponding to 6G and blue (B). Display elements 46R, 46G, 46B
are first display elements using light from a light source.

The pixel 47 includes a display element 47R corresponding to red (R) and a display element 47R corresponding to green (G).
7G and a display element 47B corresponding to blue (B). Display elements 47R, 47G, 47B
are second display elements utilizing reflection of external light.

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

<3-3. Configuration Example of Pixel Unit>
Next, the pixel unit 45 will be described with reference to FIGS. 17(A), (B), and (C).
17A, 17B, and 17C are schematic diagrams showing configuration examples of the pixel unit 45. FIG.

The pixel 46 has a display element 46R, a display element 46G, and a display element 46B. Display element 4
6R has a light source and emits red light R2 having a brightness corresponding to a gradation value corresponding to red included in the second gradation value input to the pixel 46 to the display surface side. Display element 46G, display element 46
Similarly, B emits green light G2 or blue light B2 to the display surface side.

The pixel 47 has a display element 47R, a display element 47G, and a display element 47B. Display element 4
7R reflects external light and emits red light R1 having luminance corresponding to a gradation value corresponding to red included in the first gradation value input to the pixel 47 to the display surface side. Display element 47G, display element 4
7B similarly emits green light G1 or blue light B1 to the display surface side.

[First Mode]
FIG. 17A shows an example of an operation mode in which an image is displayed by driving the display elements 47R, 47G, and 47B that reflect external light. As shown in FIG. 17A, the pixel unit 45 does not drive the pixel 46 when, for example, the illuminance of the outside light is sufficiently high. By mixing only B1), light 55 of a predetermined color can be emitted to the display surface side. As a result, driving with extremely low power consumption can be performed.

[Second mode]
FIG. 17B shows an example of an operation mode in which an image is displayed by driving the display elements 46R, 46G, and 46B. As shown in FIG. 17B, the pixel unit 45 does not drive the pixel 47 when, for example, the illuminance of the outside light is extremely low, and the light from the pixel 46 (light R2, light G2, and light B2) is not driven. ), the predetermined color light 5
5 can also be projected to the display surface side. This enables vivid display. In addition, by lowering the brightness when the illuminance of the outside light is low, it is possible to suppress glare felt by the user and reduce power consumption.

[Third mode]
FIG. 17C shows an operation of driving both the display element 47R, the display element 47G, and the display element 47B that reflect external light and the display element 46R, the display element 46G, and the display element 46B that emit light to display an image. Examples of modes are shown. As shown in FIG. 17C, the pixel unit 45 mixes six lights of light R1, light G1, light B1, light R2, light G2, and light B2 to produce light 55 of a predetermined color. It can be ejected to the display surface side.

The above is the description of the configuration example of the pixel unit 45 .

This embodiment can be implemented by appropriately combining at least part of it with other embodiments described herein.

(Embodiment 4)
Examples of the display panel that can be used for the display device of one embodiment of the present invention are described below. A display panel exemplified below has both a reflective liquid crystal element and a light-emitting element and is capable of displaying in both a transmissive mode and a reflective mode.

<4-1. Configuration example of display device>
FIG. 18A is a block diagram showing an example of the configuration of the display device 400. As shown in FIG. Display device 40
0 has a plurality of pixels 410 arranged in a matrix in the display portion 362 . The display device 400 also includes a circuit GD and a circuit SD. Also, a plurality of pixels 410 arranged in the direction R,
It has a plurality of wirings G1, a plurality of wirings G2, a plurality of wirings ANO, and a plurality of wirings CSCOM electrically connected to the circuit GD. Also, a plurality of pixels 410 arranged in the direction C, the circuit SD
and a plurality of wirings S1 and a plurality of wirings S2 electrically connected to each other.

For the sake of simplicity, the configuration having one circuit GD and one circuit SD is shown here.
and D may be provided separately.

The pixel 410 has a reflective liquid crystal element and a light emitting element. In the pixel 410, the liquid crystal element and the light emitting element overlap with each other.

FIG. 18B1 shows a structural example of the conductive layer 311b included in the pixel 410. FIG. Conductive layer 311
b functions as a reflective electrode of the liquid crystal element in the pixel 410 . An opening 451 is provided in the conductive layer 311b.

In FIG. 18B1, the light-emitting element 360 located in a region overlapping with the conductive layer 311b is indicated by a dashed line. The light-emitting element 360 overlaps with the opening 451 of the conductive layer 311b. Thereby, the light emitted by the light emitting element 360 is emitted to the display surface side through the opening 451 .

In FIG. 18B1, pixels 410 adjacent in the direction R are pixels corresponding to different colors.
At this time, as shown in FIG.
51 are preferably provided at different positions on the conductive layer 311b so that they are not arranged in a line. Accordingly, the two light-emitting elements 360 can be separated, and a phenomenon (also referred to as crosstalk) in which light emitted from the light-emitting elements 360 is incident on the colored layers of the adjacent pixels 410 can be suppressed. In addition, since two adjacent light emitting elements 360 can be arranged apart from each other, a high-definition display device can be realized even when the EL layers of the light emitting elements 360 are separately formed using a shielding mask or the like.

Alternatively, an arrangement as shown in FIG. 18B2 may be used.

If the ratio of the total area of the apertures 451 to the total area of the non-apertures is too large, the display using the liquid crystal element will be dark. Also, if the ratio of the total area of the apertures 451 to the total area of the non-apertures is too small, the display using the light emitting element 360 will be dark.

Further, if the area of the opening 451 provided in the conductive layer 311b functioning as a reflective electrode is too small, the efficiency of light extracted from the light emitted from the light emitting element 360 is reduced.

The shape of the opening 451 can be, for example, polygonal, rectangular, elliptical, circular, or cross-shaped. Further, it may be elongated strip-like, slit-like, or checkered. again,
Apertures 451 may be arranged closer to adjacent pixels. Preferably, apertures 451 are placed close to other pixels displaying the same color. Thereby, crosstalk can be suppressed.

<4-2. Circuit Configuration Example of Pixel>
FIG. 19 is a circuit diagram showing a configuration example of the pixel 410. As shown in FIG. FIG. 19 shows two adjacent pixels 410 .

The pixel 410 includes a switch SW1, a capacitor C1, a liquid crystal element 340, a switch SW2, a transistor M, a capacitor C2, a light emitting element 360, and the like. The pixel 410 is electrically connected to the wiring G1, the wiring G2, the wiring ANO, the wiring CSCOM, the wiring S1, and the wiring S2. In addition, in FIG. 19, a wiring VCO electrically connected to the liquid crystal element 340
A wiring VCOM2 electrically connected to M1 and the light emitting element 360 is shown.

FIG. 19 shows an example in which transistors are used for the switches SW1 and SW2.

The switch SW1 has a gate connected to the wiring G1, one of the source and the drain connected to the wiring S1, and the other of the source and the drain connected to one electrode of the capacitive element C1 and one electrode of the liquid crystal element 340. there is The capacitive element C1 has the other electrode connected to the wiring CSCO.
connected to M. 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 capacitive element C2 and the gate of the transistor M. . The capacitive element C2 has the other electrode connected to the transistor M
, and the wiring ANO. The transistor M has the other of its source and drain 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. 19 shows an example in which the transistor M has two gates sandwiching a semiconductor and these are connected. Thereby, the current that the transistor M can flow can be increased.

A signal for controlling the switch SW1 to be on or off can be applied 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 of the liquid crystal element 340 can be applied to the wiring S1. Wiring CSC
A predetermined potential can be applied to OM.

A signal for controlling the switch SW2 to be on or off can be applied to the wiring G2. The wiring VCOM2 and the wiring ANO can be supplied with potentials that cause a potential difference at which the light emitting element 360 emits light. A signal for controlling the on state of the transistor M can be applied to the wiring S2.

The pixels 410 shown in FIG. 19 can be driven by signals applied to the wirings G1 and S1 and can be displayed using optical modulation by the liquid crystal element 340, for example, when displaying in the reflection mode. Further, in the case of performing display in a transmissive mode, the light emitting element 360 can be driven by a signal given to the wiring G2 and the wiring S2 to emit light for display. In the case of driving in both modes, driving can be performed by signals given to the wiring G1, the wiring G2, the wiring S1, and the wiring S2.

Note that in FIG. 19, one liquid crystal element 340 and one light emitting element 360 are included in one pixel 410 .
Although the example which has and was shown, it is not restricted to this. In FIG. 20A, one pixel 410 includes one liquid crystal element 340 and four light emitting elements 360 (light emitting elements 360r, 360g, 360b, and 360b).
60w).

In FIG. 20A, a wiring G3 and a wiring S3 are connected to the pixel 410 in addition to the example in FIG.

In the example shown in FIG. 20A, for example, the four light emitting elements 360 can be red (R), green (G), blue (B), and white (W) light emitting elements. Alternatively, a reflective liquid crystal element exhibiting white color can be used as the liquid crystal element 340 . As a result, when performing display in the reflective mode, it is possible to perform white display with high reflectance. In addition, in the case of performing display in the transmissive mode, display with high color rendering can be performed with low power.

In addition, FIG. 20B shows a configuration example of the pixel 410 . The pixel 410 is the electrode 31
and a light-emitting element 360r, a light-emitting element 360g, and a light-emitting element 360b arranged around the electrode 311 . light emitting element 360r,
It is preferable that the light emitting element 360g and the light emitting element 360b have substantially the same light emitting area.

<4-3. Configuration example of display panel>
FIG. 21 is a schematic perspective view of a display panel 300 of one embodiment of the present invention. display panel 300
has a configuration in which a substrate 351 and a substrate 361 are bonded together. In FIG. 21, substrate 361
is indicated by a dashed line.

The display panel 300 includes a display portion 362, a circuit 364, wirings 365, and the like. 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. Also, FIG. 21 shows an example in which an IC 373 and an FPC 372 are mounted on the substrate 351 . Therefore, the configuration shown in FIG. 21 can also be said to be a display module having the display panel 300, the FPC 372 and the IC 373. FIG.

For the circuit 364, for example, a circuit functioning as a scanning line driver circuit can be used.

The wiring 365 has a function of supplying signals and power to the display portion 362 and the circuit 364 . The signal and power are input to the wiring 365 from the outside through the FPC 372 or from the IC 373 .

Further, in FIG. 21, the substrate 351 is formed by a COG (Chip On Glass) method or the like.
shows an example in which an IC 373 is provided in . The IC 373 is, for example, a scanning line driving circuit,
Alternatively, an IC having a function as a signal line driver circuit or the like can be applied. Note that the display panel 30
0 includes a circuit functioning as a scanning line driving circuit and a signal line driving circuit, or a circuit functioning as a scanning line driving circuit and a signal line driving circuit is provided externally to drive the display panel 300 via the FPC 372. In the case of inputting a signal, the IC 373 may be omitted. In addition, IC373, by the COF (Chip On Film) method, etc.
It may be mounted on the FPC 372 .

FIG. 21 shows an enlarged view of part of the display section 362. As shown in FIG. In the display portion 362, conductive layers 311b included in a plurality of display elements are arranged in matrix. The conductive layer 311b has a function of reflecting visible light and functions as a reflective electrode of the liquid crystal element 340, which will be described later.

Also, as shown in FIG. 21, the conductive layer 311b has an opening. Further, a light-emitting element 360 is provided on the substrate 351 side of the conductive layer 311b. Light from the light emitting element 360 passes through the conductive layer 311b.
is injected to the substrate 361 side through the opening of .

A touch sensor can be provided over the substrate 361 . For example, a sheet-like capacitive touch sensor 366 may be provided so as to overlap the display portion 362 . Alternatively, a touch sensor may be provided between the substrate 361 and the substrate 351 . Substrate 361 and substrate 35
1, an optical touch sensor using a photoelectric conversion element may be applied in addition to the capacitive touch sensor.

<4-4. Example of cross-sectional configuration>
FIG. 22 shows part of the region including the FPC 372 of the display panel illustrated in FIG.
4, a part of the region including the display unit 362, and the touch sensor 366 are cut.

The display panel has an insulating layer 220 between substrates 351 and 560 . Also the substrate 35
1 and the insulating layer 220, the light emitting element 360, the transistor 201, the transistor 205,
It has a transistor 206, a coloring layer 134, and the like. Also, between the insulating layer 220 and the substrate 560,
It has a liquid crystal element 340, an insulating layer 180, a colored layer 131, an insulating layer 121, a touch sensor 366, and the like. Also, the touch sensor 366 and the insulating layer 121 are adhered via the adhesive layer 176 , and the substrate 351 and the light emitting element 360 are adhered via the 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 the transistors 205 and 206 are both formed over the surface of the insulating layer 220 on the substrate 351 side, they can be manufactured using the same process.

The substrate 560 includes the touch sensor 366, the colored layer 131, the light shielding layer 132, the insulating layer 121,
The insulating layer 180, the conductive layer 313 functioning as a common electrode for the liquid crystal element 340, and the alignment film 133b
, an insulating layer 117 and the like are provided. The insulating layer 117 functions as a spacer for holding the cell gap of the liquid crystal element 340 .

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 on the substrate 351 side of the insulating layer 220 . Part of the insulating layer 211 functions as a gate insulating layer of each transistor. An insulating layer 212, an insulating layer 213, and an insulating layer 214 are provided over each transistor. In addition, insulating layer 2 covers insulating layer 214 .
15 are provided. The insulating layer 214 and the insulating layer 215 function as planarization layers. Note that here, the insulating layers 212 and 213 are used as the insulating layers that cover the transistors and the like.
, and the insulating layer 214 are shown, but the present invention is not limited to this, and may have four or more layers, a single layer, or two layers. Insulating layer 2 that also functions as a planarization layer
14 may be omitted if unnecessary.

The transistors 201 , 205 , and 206 each include a conductive layer 221 partly functioning as a gate, a conductive layer 222 partly functioning as a source or a drain, and a semiconductor layer 231 . Here, the same hatching pattern is applied 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 312, and a conductive layer 313 are stacked. Moreover, the substrate 35 of the conductive layer 311a
A conductive layer 311b that reflects visible light is provided in contact with the first side. Conductive layer 311b has opening 251 . In addition, the conductive layers 311a and 313 contain a material that transmits visible light. Further, an alignment film 133a is provided between the liquid crystal 312 and the conductive layer 311a so that the liquid crystal 312
and the conductive layer 313, an alignment film 133b is provided.

In the liquid crystal element 340, the conductive layer 311b has a function of reflecting visible light, and the conductive layer 311b has a function of reflecting visible light.
3 has a function of transmitting visible light. Light incident from the substrate 560 side passes through the conductive layer 313 and the liquid crystal 312 and is reflected by the conductive layer 311b. Then, liquid crystal 312 and conductive layer 313
again to reach the substrate 560 . At this time, the orientation of the liquid crystal 312 can be controlled by a voltage applied between the conductive layer 311b and the conductive layer 313, so that the optical modulation of light can be controlled.
That is, the intensity of light emitted through substrate 560 can be controlled. In addition, the colored layer 131 absorbs light other than the light in the specific wavelength range, so that the extracted light becomes, 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 a conductive layer 191, an EL layer 192, and a 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 contains a material that reflects visible light, and the conductive layers 191 and 193a contain a material that transmits visible light. Light emitted by the light emitting element 360 is emitted to the substrate 560 side through the colored layer 134, the insulating layer 220, the opening 251, the conductive layer 313, and the like.

Here, as shown in FIG. 22, the opening 251 is preferably provided with a conductive layer 311a that transmits visible light. As a result, the liquid crystal 312 is oriented in the region overlapping the opening 251 in the same manner as in the other regions, so that it is possible to prevent the liquid crystal from being oriented poorly at the boundary between these regions and causing unintended leakage of light.

A film 13d having an anti-glare pattern is disposed on the outer surface of the substrate 560. As shown in FIG. Reflected light can be scattered by the film 13d on which the anti-glare pattern is formed, and the display by the reflective display element can be made easier to see. In addition, dirt such as fingerprints can be made less likely to adhere.

An insulating layer 217 is provided over the insulating layer 216 covering the end portion of the conductive layer 191 . The insulating layer 217 functions as a spacer that prevents the insulating layer 220 and the substrate 351 from approaching each other more than necessary. In addition, the EL layer 192 and the conductive layer 193a are covered with a shielding mask (metal mask).
may have a function of preventing the shielding mask from coming into contact with the formation surface. Note that the insulating layer 217 may be omitted if unnecessary.

One of the source and the 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 the source and the drain of the transistor 206 is connected to the conductive layer 3 through the connection portion 207.
11b are electrically connected. The conductive layer 311b and the conductive layer 311a are provided in contact,
These are electrically connected. Here, the connecting portion 207 is a portion that connects the conductive layers provided on both surfaces of the insulating layer 220 through an opening provided in the insulating layer 220 .

A connection portion 204 is provided in a region where the substrate 351 and the substrate 560 do not overlap. The connecting portion 204 has a configuration similar to that of the connecting portion 207 . The upper surface of the connecting portion 204 is the conductive layer 31
A conductive layer obtained by processing the same conductive film as 1a is exposed. As a result, the connecting portion 20
4 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. Connection part 2
In 52, a conductive layer obtained by processing the same conductive film as the conductive layer 311a, and the conductive layer 311a.
3 are electrically connected by a connector 243 . Therefore, a signal or potential input from the FPC 372 connected to the substrate 351 side can be supplied to the conductive layer 313 formed on the substrate 560 side through the connection portion 252 .

As the connector 243, for example, conductive particles can be used. As the conductive particles, particles such as organic resin or silica whose surface is coated 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 coated with two or more kinds of metal materials in layers, such as coating nickel with gold. Further, it is preferable to use a material that is elastically deformable or plastically deformable as the connecting body 243 . At this time, the connector 243, which is a conductive particle, may have a vertically crushed shape as shown in FIG. By doing so, the contact area between the connector 243 and the conductive layer electrically connected thereto is increased, the contact resistance can be reduced, and the occurrence of defects such as poor connection can be suppressed.

The connection body 243 is preferably arranged so as to be covered with the adhesive layer 141 . For example, the connecting members 243 may be dispersed in the adhesive layer 141 before curing.

FIG. 22 shows an example in which the transistor 201 is provided as an example of the circuit 364 .

In FIG. 22, as an example of the transistor 201 and the transistor 205, a structure in which a semiconductor layer 231 in which a channel is formed is sandwiched between two gates is applied. One gate is composed of the conductive layer 221, and the other gate is composed of the conductive layer 223 overlapping with the semiconductor layer 231 with the 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 to them. Such a transistor can increase field-effect mobility and increase on-current compared to other transistors. As a result, a circuit that can be driven at high speed can be manufactured. Furthermore, it is possible to reduce the area occupied by the circuit section. By using a transistor with a large on-current, it is possible to reduce the signal delay in each wiring even if the number of wiring increases when the display panel becomes larger or has higher definition, thereby suppressing display unevenness. 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. Further, the plurality of transistors included in the circuit 364 may all have the same structure, or transistors with different structures may be used in combination. Further, the plurality of transistors included in the display portion 362 may all have the same structure, or transistors with different structures may be used in combination.

At least one of the insulating layer 212 and the insulating layer 213 covering each transistor is preferably made of a material into which impurities such as water and hydrogen are difficult to diffuse. That is, the insulating layer 212 or the insulating layer 213 can function as a barrier film. By adopting such a structure, it is possible to effectively suppress the diffusion of impurities from the outside into the transistor, and a highly reliable display panel can be realized.

<4-5. About each component>
Below, each component shown above is demonstrated.

[substrate]
A material having a flat surface can be used for a substrate included in the display panel. A material that transmits the light is used for the substrate on the side from which the light from the display element is extracted. For example, glass, quartz,
Materials such as ceramics, sapphire, and organic resins can be used.

By using a thin substrate, the weight and thickness of the display panel can be reduced. Furthermore, a flexible display panel can be realized by using a substrate that is thick enough to be flexible.

In addition, since the substrate on the side from which emitted light is not extracted does not need to have a light-transmitting property, a metal substrate or the like can be used in addition to the above substrates. Since the metal substrate has high thermal conductivity and can easily conduct heat to the entire substrate, local temperature rise in the display panel can be suppressed.
preferable. In order to obtain flexibility and bendability, the thickness of the metal substrate should be between 10 μm and 200 μm.
The following is preferable, and 20 μm or more and 50 μm or less is more preferable.

The material constituting the metal substrate is not particularly limited, but metals such as aluminum, copper, and nickel, or alloys such as aluminum alloys and stainless steel can be preferably used.

Alternatively, a substrate subjected to an insulating treatment such as by oxidizing the surface of a metal substrate or forming an insulating film on the surface thereof may be used. For example, coating methods such as spin coating and dipping,
An insulating film may be formed using an electrodeposition method, a vapor deposition method, a sputtering method, or the like, or an oxide film may be formed on the surface of the substrate by leaving or heating in an oxygen atmosphere, or by an anodic oxidation method or the like. good too.

Materials having flexibility and transparency to visible light include, for example, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN);
Polyacrylonitrile resin, polyimide resin, polymethylmethacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyvinyl chloride resin, polytetrafluoroethylene ( PTFE) resin and the like. In particular, it is preferable to use a material with a low coefficient of thermal expansion. For example, polyamideimide resin, polyimide resin, PET, etc., having a coefficient of thermal expansion of 30×10 ⁻⁶ /K or less can be preferably used. A substrate obtained by impregnating glass fibers with an organic resin, or a substrate obtained by mixing an inorganic filler with an organic resin to reduce the coefficient of thermal expansion can also be used. Since a substrate using such a material is light in weight, a display panel using the substrate can also be light in weight.

When a fibrous body is included in the material, the fibrous body uses high-strength fibers of an organic compound or an inorganic compound. High-strength fibers specifically refer to fibers having a high tensile modulus or Young's modulus, and representative examples include polyvinyl alcohol fibers, polyester fibers, polyamide fibers, polyethylene fibers, aramid fibers, Polyparaphenylenebenzobisoxazole fibers, glass fibers, or carbon fibers may be mentioned. Examples of glass fibers include glass fibers using E glass, S glass, D glass, Q glass, and the like. These may be used in the form of woven fabric or non-woven fabric, and a structure obtained by impregnating this fibrous body with a resin and curing the resin may be used as a flexible substrate. It is preferable to use a structure made of a fibrous body and a resin as the substrate having flexibility, because the reliability against damage due to bending or local pressure is improved.

Alternatively, a thin glass, metal, or the like having flexibility can be used for the substrate. Alternatively, a composite material in which glass and a resin material are bonded together by an adhesive layer may be used.

A flexible substrate has a hard coat layer (for example, silicon nitride, aluminum oxide, etc.) that protects the surface of the display panel from scratches, and a layer made of a material that can disperse pressure (for example, aramid resin). It may be laminated. In addition, an insulating film with low water permeability may be laminated on a flexible substrate in order to suppress deterioration in the life of the display element due to moisture or the like. 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 also be used by laminating a plurality of layers. In particular, when a structure including a glass layer is employed, barrier properties against water and oxygen can be improved, and a highly reliable display panel can be obtained.

[Transistor]
A transistor includes a conductive layer functioning as a gate electrode, a semiconductor layer, a conductive layer functioning as a source electrode, a conductive layer functioning as a drain electrode, and an insulating layer functioning as a gate insulating layer. The above description shows a case where a transistor with a bottom-gate structure 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, the transistor structure may be either a top-gate type or a bottom-gate type. Alternatively, gate electrodes may be provided above and below the channel.

The crystallinity of the semiconductor material used for the transistor is not particularly limited, and amorphous semiconductors,
Any crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single-crystal semiconductor, or a semiconductor partially including a crystal region) may be used. It is preferable to use a crystalline semiconductor because deterioration of transistor characteristics can be suppressed.

In addition, semiconductor materials used for transistors have an energy gap of 2 eV or more,
Metal oxides with a voltage of preferably 2.5 eV or higher, more preferably 3 eV or higher can be used. Typically, it is an oxide semiconductor containing indium or the like.
C-OS or the like can be used.

A transistor including an oxide semiconductor, which has a wider bandgap and a lower carrier density than silicon, can retain charge accumulated in a capacitor connected in series with the transistor for a long time due to low off-state current. is possible.

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

When the oxide semiconductor constituting the semiconductor layer is an In--M--Zn oxide, the atomic ratio of the metal elements in the sputtering target used for forming the In--M--Zn oxide is In≧
It is preferable to satisfy M, Zn≧M. The atomic ratios of the metal elements in such a sputtering target are In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, I
n: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 and the like are preferred. It should be noted that the atomic ratio of the metal elements in the semiconductor layer to be deposited includes a variation of plus or minus 40% of the atomic ratio of the metal elements contained in the sputtering target.

The bottom-gate transistor described as an example in this embodiment is preferable because the number of manufacturing steps can be reduced. In addition, by using an oxide semiconductor at this time, it can be formed at a lower temperature than polycrystalline silicon, and a material with low heat resistance can be used as a material for wiring and electrodes in a layer below the semiconductor layer and a material for the substrate. , the range of material selection can be expanded. 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 or less. ³ or less,
More preferably, it is less than 1×10 ¹⁰ /cm ³ , and an oxide semiconductor with 1×10 ⁻⁹ /cm ³ or more can be used. Such an oxide semiconductor is called a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Accordingly, the oxide semiconductor has a low impurity concentration and a low defect state density, and thus has stable characteristics.

Note that the material is not limited to these, and a material having an appropriate composition may be used according to the required semiconductor characteristics and electrical characteristics (field effect mobility, threshold voltage, etc.) of the transistor. In addition, in order to obtain the required semiconductor characteristics of the transistor, it is preferable to appropriately set the carrier density, impurity concentration, defect density, atomic ratio of metal elements and oxygen, interatomic distance, density, etc. of the semiconductor layer. .

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

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

Further, when nitrogen is contained in the oxide semiconductor forming the semiconductor layer, electrons as carriers are generated, the carrier density increases, and the oxide semiconductor tends to be n-type. As a result, a transistor including an oxide semiconductor containing nitrogen tends to have normally-on characteristics. Therefore, the nitrogen concentration in the semiconductor layer obtained by secondary ion mass spectrometry is 5×10 ¹⁸ atoms/cm ³ .
It is preferable to:

The semiconductor layer may also have a non-single-crystal structure, for example. The non-single-crystal structure is, for example, CAAC-OS (C-Axis Aligned Crystalline
ine Oxide Semiconductor), polycrystalline, microcrystalline, or amorphous structures. Among the non-single-crystal structures, the amorphous structure has the highest density of defect states, CA
AC-OS has the lowest defect level density.

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

Note that the semiconductor layer includes a region having an amorphous structure, a region having a microcrystalline structure, a region having a polycrystalline structure, and a CAA region.
A mixed film containing two or more of the C—OS region and the single crystal structure region may be used. The mixed film may have, for example, a single-layer structure or a laminated structure containing two or more of the above-described regions.

[Configuration of CAC-OS]
Details of the metal oxide having a CAC structure that can be used for the semiconductor layer of the transistor disclosed in one embodiment of the present invention are described below with reference to FIGS. Here, CA
A CAC-OS formed over the insulating film 106 will be described as a representative example of the metal oxide having the C structure.

That is, the CAC-OS is, for example, uneven distribution of elements constituting a metal oxide to form a region 101 and a region 102 containing each element as a main component, and the regions are mixed and arranged in a mosaic shape. formed or dispersed. That is, the element that constitutes the metal oxide has a thickness of 0.5 nm or more.
This is one configuration of a material unevenly distributed with a size of 0 nm or less, preferably 0.5 nm or more and 3 nm or less, or in the vicinity thereof.

The physical properties of a region where a specific element is unevenly distributed are determined by the properties of the element. For example, a region in which an element that tends to be an insulator relatively among elements constituting a metal oxide is unevenly distributed becomes a dielectric region. On the other hand, among the elements constituting the metal oxide, a region in which elements relatively tend to be conductors are unevenly distributed becomes a conductor region. In addition, the conductor region and the dielectric region are mixed in a mosaic shape, and the material functions as a semiconductor.

That is, the metal oxide in one aspect of the present invention is a kind of matrix composite or metal matrix composite in which materials with different physical properties are mixed.

Note that the oxide semiconductor preferably contains at least indium. Indium and zinc are particularly preferred. In addition to them, element M (M is gallium, aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium,
one selected from iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc.;
or multiple species) may be included.

For example, CAC-OS in In--Ga--Zn oxide (In--
Ga--Zn oxide may be specifically referred to as CAC-IGZO. ) refers to indium oxide (hereinafter, InO _X1 (X1 is a real number greater than 0)) or indium zinc oxide (hereinafter, In _X2 Zn _Y2 O _Z2 (X2, Y2, and Z2 are greater than 0). ), gallium oxide (hereinafter referred to as GaO _X3 (X3 is a real number greater than 0)), or gallium zinc oxide (hereinafter referred to as Ga _X4 Zn _Y4 O _Z4 (X4, Y4 , and Z4 is a real number greater than 0.) and so on, and the material is separated into a mosaic shape, and the mosaic InO _X1 or In _X2 Zn _Y2 O _Z2 is uniformly distributed in the film. It is a configuration (hereinafter also referred to as a cloud shape).

That is, CAC-OS has a region mainly composed of GaO _X3 and a region containing In _X2 Zn _Y2 O _Z2
, or a region containing InO _X1 as its main component. In this specification, for example, the first region means that the atomic ratio of In to the element M in the first region is greater than the atomic ratio of In to the element M in the second region.
Assume that the In concentration is higher than that of the second region.

Note that IGZO is a common name, and may refer to one compound of In, Ga, Zn, and O. As a representative 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).

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 the material composition of oxide semiconductors. CAC-OS is In,
In the material structure containing Ga, Zn, and O, nanoparticulate regions containing Ga as the main component are partially observed, and nanoparticulate regions containing In as the main component are partially observed, each in a mosaic pattern. Refers to a randomly distributed configuration. Therefore, in CAC-OS the crystal structure is a secondary factor.

Note that CAC-OS does not include a stacked structure of two or more films with different compositions. For example, it does not include a structure consisting of two layers, a film containing In as a main component and a film containing Ga as a main component.

Note that a region containing GaO _X3 as a main component and In _X2 Zn _Y2 O _Z2 or InO _X1
In some cases, a clear boundary cannot be observed with the region where is the main component.

Instead of gallium, aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc. When one or more of these elements are included, the CAC-OS has a nanoparticulate region containing the element as a main component in part and a nanoparticulate region containing In as a main component in part. are observed, and are randomly dispersed in a mosaic pattern.

[Analysis of CAC-OS]
Next, measurement results of an oxide semiconductor deposited over a substrate using various measurement methods are described.

[Sample structure and preparation method]
Nine samples according to one embodiment of the present invention are described below. Each sample, respectively,
The substrate temperature and the oxygen gas flow ratio are different when the oxide semiconductor is deposited.
Note that the sample has a structure including a substrate and an oxide semiconductor over the substrate.

A method for manufacturing each sample will be described.

First, a glass substrate is used as a substrate. Subsequently, a 100-nm-thick In--Ga--Zn oxide is formed as an oxide semiconductor over the glass substrate using a sputtering apparatus.
The film formation conditions are such that the pressure in the chamber is 0.6 Pa, and an oxide target (In:Ga:Zn=4:2:4.1 [atomic ratio]) is used as the target. Also, AC power of 2500 W is supplied to the oxide target installed in the sputtering apparatus.

Note that, as conditions for forming the oxide film, the substrate temperature was set to a temperature that is not intentionally heated (hereinafter, also referred to as room temperature or R.T.), 130° C., or 170° C. In addition, the flow rate ratio of oxygen gas to the mixed gas of Ar and oxygen (hereinafter also referred to as oxygen gas flow rate ratio) was 10%.
, 30%, or 100% to make 9 samples.

[Analysis by X-ray diffraction]
In this item, X-ray diffraction (XRD: X-ray diffracti
on) Describe the results of the measurement. In addition, D8 ADVANCE by Bruker was used as an XRD apparatus. In addition, the conditions are θ/
In 2θ scanning, the scanning range is 15 degrees. to 50deg. , a step width of 0.02d
eg. , a scanning speed of 3.0 deg. / minutes.

FIG. 24 shows the results of XRD spectrum measurement using the out-of-plane method. In FIG. 24, the upper part shows the measurement results of the sample with a substrate temperature condition of 170° C. during film formation, the middle part shows the measurement results of the sample with a substrate temperature condition of 130° C. during film formation, and the lower part shows the measurement results during film formation. The substrate temperature condition of R.I. T. shows the measurement results for the sample. In addition, the left column shows the measurement results of the sample with an oxygen gas flow rate ratio of 10%, the middle column shows the measurement results of the sample with an oxygen gas flow rate ratio of 30%, and the right column shows the oxygen gas flow rate. Measurement results for a sample with a ratio condition of 100% are shown.

The XRD spectrum shown in FIG. 24 increases the peak intensity near 2θ=31° by increasing the substrate temperature during film formation or increasing the ratio of the oxygen gas flow rate during film formation. The peak near 2θ=31° is that of a crystalline IGZO compound (CAAC (c-axis aligned crystal
line)-IGZO. ).

Further, in the XRD spectrum shown in FIG. 24, a clear peak did not appear as the substrate temperature during film formation was lower or as the oxygen gas flow ratio was smaller. Therefore, it can be seen that no orientation in the ab plane direction and the c-axis direction of the measurement region is observed in the sample with a low substrate temperature or a low oxygen gas flow rate during film formation.

[Analysis by electron microscope]
In this item, the substrate temperature R.O.D. T. , and a sample prepared with an oxygen gas flow rate ratio of 10%, HAADF (High-Angle Annular Dark Field)-S
TEM (Scanning Transmission Electron Microscope)
scope) will explain the results of observation and analysis (hereinafter referred to as HAADF-
An image acquired by STEM is also called a TEM image. ).

The result of image analysis of a planar image (hereinafter also referred to as a planar TEM image) and a cross-sectional image (hereinafter also referred to as a cross-sectional TEM image) obtained by HAADF-STEM will be described. The TEM image was observed using a spherical aberration correction function. In addition, HAADF-STEM
The images were taken using an atomic resolution analytical electron microscope JEM-ARM200F manufactured by JEOL Ltd. with an accelerating voltage of 200 kV and an electron beam with a beam diameter of about 0.1 nmφ.

FIG. 25A shows the substrate temperature R.D. during film formation. T. , and a planar TEM image of a sample produced with an oxygen gas flow ratio of 10%. FIG. 25B shows the substrate temperature R.D. during film formation. T. , and a cross-sectional TEM image of a sample produced with an oxygen gas flow ratio of 10%.

[Analysis of electron beam diffraction pattern]
In this item, the substrate temperature R.O.D. T. , and an oxygen gas flow ratio of 10%, and an electron beam with a probe diameter of 1 nm (also referred to as a nanobeam electron beam) to obtain an electron beam diffraction pattern.

As shown in FIG. 25(A), the substrate temperature R.D. T. , and an electron beam diffraction pattern indicated by black point a1, black point a2, black point a3, black point a4, and black point a5 in the planar TEM images of the samples produced at an oxygen gas flow ratio of 10%. The observation of the electron beam diffraction pattern is performed while moving at a constant speed from the position of 0 seconds to the position of 35 seconds while irradiating the electron beam. FIG. 25(C) shows the result of black point a1, FIG. 25(D) shows the result of black point a2, and FIG. 25 shows the result of black point a3.
(E), the result of black point a4 is shown in FIG. 25(F), and the result of black point a5 is shown in FIG. 25(G).

25(C), 25(D), 25(E), 25(F), and 25(G), a circular (ring-like) region with high brightness can be observed. Also, a plurality of spots can be observed in a ring-shaped area.

Also, the substrate temperature R.D. during film formation shown in FIG. T. , and an oxygen gas flow rate ratio of 10%
In the cross-sectional TEM image of the sample prepared in 1., electron beam diffraction patterns indicated by black points b1, black points b2, black points b3, black points b4, and black points b5 are observed. FIG. 25(H) shows the result of black point b1, FIG. 25(I) shows the result of black point b2, FIG. 25(J) shows the result of black point b3, and FIG. 25 shows the result of black point b4.
(K) and the result of black point b5 are shown in FIG. 25(L).

25(H), 25(I), 25(J), 25(K), and 25(L), a ring-shaped region with high brightness can be observed. Also, a plurality of spots can be observed in a ring-shaped area.

Here, for example, when an electron beam with a probe diameter of 300 nm is incident parallel to the sample surface to a CAAC _{-OS having an InGaZnO 4 crystal} , the (00
9) A diffraction pattern is seen that contains spots due to the surface. In other words, CAAC-OS
has c-axis orientation, and the c-axis is oriented in a direction substantially perpendicular to the formation surface or upper surface. On the other hand, when an electron beam with a probe diameter of 300 nm is incident on the same sample perpendicularly to the sample surface, a ring-shaped diffraction pattern is confirmed. In other words, it can be seen that the CAAC-OS has no orientation along the a-axis and the b-axis.

In addition, an oxide semiconductor having microcrystals (nano crystalline oxide
semiconductor. Hereinafter, it will be referred to as nc-OS. ), a diffraction pattern like a halo pattern is observed when electron beam diffraction is performed using an electron beam with a large probe diameter (for example, 50 nm or more). Also, when nanobeam electron diffraction using an electron beam with a small probe diameter (for example, less than 50 nm) is performed on the nc-OS, bright points (spots) are observed. In addition, when nanobeam electron diffraction is performed on the nc-OS, a circular (ring-like) region with high brightness may be observed. Furthermore, a plurality of bright spots may be observed in the ring-shaped area.

Substrate temperature R.D. during film formation T. , and an oxygen gas flow ratio of 10%, the electron beam diffraction pattern has a ring-shaped region of high brightness and a plurality of bright spots in the ring region. Therefore, the substrate temperature R.D. T. , and an oxygen gas flow ratio of 10%, the electron beam diffraction pattern is nc-OS, and does not have orientation in the planar direction and the cross-sectional direction.

As described above, an oxide semiconductor with a low substrate temperature or a low oxygen gas flow rate during deposition has properties that are clearly different from those of an oxide semiconductor film with an amorphous structure and an oxide semiconductor film with a single crystal structure. can be estimated.

[Elemental analysis]
In this item, energy dispersive X-ray spectroscopy (EDX: Energy Dispersi
EDX mapping was acquired and evaluated using X-ray spectroscopy) to determine the substrate temperature during film formation. T. , and the results of elemental analysis of the samples produced at an oxygen gas flow ratio of 10% will be described. For the EDX measurement, an energy dispersive X-ray analyzer JED-2300T manufactured by JEOL Ltd. is used as an elemental analyzer.
A Si drift detector is used to detect X-rays emitted from the sample.

In the EDX measurement, an electron beam is irradiated to each point in the region to be analyzed of the sample, and the energy and the number of occurrences of characteristic X-rays generated from the sample are measured to obtain an EDX spectrum corresponding to each point. In this embodiment, the peaks of the EDX spectrum at each point are defined as the electronic transition to the L shell of the In atom, the electronic transition to the K shell of the Ga atom, the electronic transition to the K shell of the Zn atom, and the K shell of the O atom. and calculate the ratio of each atom at each point. By performing this on the analysis target region of the sample, EDX mapping showing the distribution of the ratio of each atom can be obtained.

FIG. 26 shows the substrate temperature R.D. during film formation. T. , and an EDX mapping of a cross-section of a sample produced at an oxygen gas flow rate of 10%. FIG. 26A is EDX mapping of Ga atoms (the ratio of Ga atoms to all atoms is in the range of 1.18 to 18.64 [atomic %]). FIG. 26B is EDX mapping of In atoms (the ratio of In atoms to all atoms is in the range of 9.28 to 33.74 [atomic %]). Figure 26
(C) is EDX mapping of Zn atoms (the ratio of Zn atoms to all atoms is in the range of 6.69 to 24.99 [atomic %]). 26(A) and 26(
B) and FIG. 26C show the substrate temperature R.D. during film formation. T. , and an oxygen gas flow rate ratio of 10%
The same area is shown in the cross section of the sample prepared in . The EDX mapping shows the ratio of elements by light and dark so that the more elements measured in the range, the brighter the area, and the less elements measured, the darker the area. Also, the EDX mapping magnification shown in FIG.
Ten thousand times.

In the EDX mapping shown in FIGS. 26(A), 26(B), and 26(C), a distribution of relative light and dark can be seen in the image, and the substrate temperature R.F. T. , and oxygen gas flow ratio 10
It can be confirmed that each atom is present with a distribution in the sample prepared by %. 26A, 26B, and 26C, attention is paid to the range surrounded by solid lines and the range surrounded by broken lines.

In FIG. 26A, the range surrounded by solid lines includes many relatively dark areas, and the range surrounded by dashed lines includes many relatively bright areas. In FIG. 26B, the range surrounded by solid lines includes many relatively bright areas, and the range surrounded by broken lines includes many relatively dark areas.

In other words, the area surrounded by the solid line is the area with relatively many In atoms, and the area surrounded by the dashed line is the area of In atoms.
It is a region with relatively few atoms. Here, in FIG. 26C, in the range enclosed by the solid line, the right side is a relatively bright area and the left side is a relatively dark area. Therefore, the range surrounded by the solid line is a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component.

In addition, the range surrounded by the solid line is a region with relatively few Ga atoms, and the range surrounded by the dashed line is a region of Ga atoms.
It is a region with a relatively large number of atoms. In FIG. 26C, in the range enclosed by the dashed line, the upper left area is a relatively bright area, and the lower right area is a relatively dark area. Therefore, the range enclosed by the dashed line is a region where the main component is GaO _X3 or Ga _X4 Zn _Y4 O _Z4 .

26(A), 26(B), and 26(C), the distribution of In atoms is
_{InX _
2ZnY2OZ2} appears to be connected to each other via a region _{containing 2ZnY2OZ2 as} a main component. Thus, the region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component is
It is formed spreading like a cloud.

In—Ga—Z having a structure in which a region containing GaO _X3 or the like as a main component and a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component are unevenly distributed and mixed.
The n-oxide can be called CAC-OS.

In addition, the crystal structure of CAC-OS has an nc structure. n that CAC-OS has
The c structure is an IGZO containing a single crystal, polycrystal, or CAAC structure in the electron diffraction pattern.
In addition to the luminescent spots (spots) caused by , there are several luminescent spots (spots). Alternatively, the crystal structure is defined as a ring-shaped region of high brightness appearing in addition to several or more bright points (spots).

26(A), 26(B), and 26(C), a region containing GaO _X3 or the like as a main component and a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component Sizes are observed between 0.5 nm and 10 nm, or between 1 nm and 3 nm. In EDX mapping, the diameter of the region containing each element as a main component is preferably 1 nm or more and 2 nm or less.

As described above, the CAC-OS has a structure different from that of the IGZO compound in which the metal element is uniformly distributed, and has properties different from those of the IGZO compound. That is, the CAC-OS is phase-separated into a region containing GaO 2 _X3 or the like as a main component and a region containing In _X2 Zn _Y2 O _Z2 or InO 2 _X1 as a main component, and a region containing each element as a main component. has a mosaic structure.

Here, the region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component is GaO _X
3 or the like as the main component, the region has high conductivity. In other words, In _X2 Zn
When carriers flow through a region _{containing Y2OZ2} or _InO2X1 as a main component, conductivity as an oxide semiconductor is developed. Therefore, In _X2 Zn _Y2 O _Z2 , or I
A high field-effect mobility (μ) can be realized by distributing the regions containing nO _X1 as a main component in the form of clouds in the oxide semiconductor.

On the other hand, a region containing GaO _X3 or the like as a main component is In _X2 Zn _Y2 O _Z2 or InO
This region has a higher insulating property than the region _{containing X1} as the main component. That is, by distributing a region containing _GaOx3 or the like as a main component in the oxide semiconductor, leakage current can be suppressed and favorable switching operation can be realized.

Therefore, when the CAC-OS is used for a semiconductor element, the insulating properties caused by GaO _X3 and the like and the conductivity caused by In _X2 Zn _Y2 O _Z2 or InO _X1 act in a complementary manner. On-current (I _on ) and high field effect mobility (μ) can be achieved.

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

Alternatively, silicon may be used for a semiconductor in which a channel of a transistor is formed. Although amorphous silicon may be used as silicon, it is particularly preferable to use crystalline silicon. 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 monocrystalline silicon, and has higher field effect mobility and higher reliability than amorphous silicon.

The bottom-gate transistor described as an example in this embodiment is preferable because the number of manufacturing steps can be reduced. In addition, by using amorphous silicon at this time, since it can be formed at a lower temperature than polycrystalline silicon, it is possible to use a material with low heat resistance as a material for wiring and electrodes in a layer below the semiconductor layer and a material for the substrate. , the range of material selection can be expanded. 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-aligned manner and variations in characteristics can be reduced. At this time, it is particularly suitable when using polycrystalline silicon, single crystal silicon, or the like.

[Conductive layer]
In addition to the gate, source and drain of transistors, materials that can be used for conductive layers such as various wirings and electrodes that constitute display devices include aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, A metal such as tantalum or tungsten, or an alloy containing this as a main component can be used. Also, a film containing these materials can be used as a single layer or as a laminated structure. For example, a single-layer structure of an aluminum film containing silicon, a two-layer structure in which an aluminum film is stacked over a titanium film, a two-layer structure in which an aluminum film is stacked over a tungsten film, and a copper film over a copper-magnesium-aluminum alloy film. A two-layer structure, a two-layer structure in which a copper film is laminated on a titanium film, a two-layer structure in which a copper film is laminated on a tungsten film, a titanium film or a titanium nitride film, and an aluminum film or a copper film overlaid thereon and further a titanium film or a titanium nitride film is formed thereon, a molybdenum film or a molybdenum nitride film is laminated thereon, an aluminum film or a copper film is laminated thereon, and a molybdenum film or a There is a three-layer structure that forms a molybdenum nitride film, and the like. 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, a conductive oxide such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide to which gallium is added, or graphene can be used. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or alloy materials containing such metal materials can be used. Alternatively, a nitride of the metal material (eg, titanium nitride) or the like may be used. Note that when a metal material or an alloy material (or a nitride thereof) is used, it may be thin enough to have translucency. Alternatively, a stacked film of any of the above materials can be used as the conductive layer. For example, it is preferable to use a laminated film of a silver-magnesium alloy and indium tin oxide, because the conductivity can be increased.
These can also be used for conductive layers such as various wirings and electrodes that constitute a display device, and conductive layers of display elements (conductive layers functioning as pixel electrodes and common electrodes).

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

Further, the light-emitting element is preferably provided between a pair of insulating films with low water permeability.
As a result, it is possible to prevent impurities such as water from entering the light-emitting element, and to prevent deterioration of the reliability of the device.

Examples of the insulating film with low water permeability include a film containing nitrogen and silicon such as a silicon nitride film and a silicon nitride oxide film, a film containing nitrogen and aluminum such as an aluminum nitride film, and the like. again,
A silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or the like may be used.

For example, the water vapor permeation amount 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 1×1
0 ⁻⁷ [g/(m ² ·day)] or less, more preferably 1×10 ⁻⁸ [g/(m ² ·d
ay)] below.

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

Liquid crystal elements to which various modes are applied can be used as the liquid crystal element. For example, in addition to VA mode, TN (Twisted Nematic) mode, IPS (In
-Plane-Switching) mode, FFS (Fringe Field Sw
etching) mode, ASM (Axially Symmetric alignment)
d Micro-cell) mode, OCB (Optically Compensated)
ed Birefringence) mode, FLC (Ferroelectric L
Liquid Crystal) mode, AFLC (Anti-Ferroelectric
A liquid crystal element to which a Liquid Crystal mode or the like is applied can be used.

Note that the liquid crystal element is an element that controls transmission or non-transmission of light by the 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). Liquid crystals used in liquid crystal elements include thermotropic liquid crystals, low-molecular-weight liquid crystals, polymer liquid crystals, and polymer-dispersed liquid crystals (PDLC).
: Polymer Dispersed Liquid Crystal), ferroelectric liquid crystal, antiferroelectric liquid crystal, and the like can be used. These liquid crystal materials exhibit a cholesteric phase, a smectic phase, a cubic phase, a chiral nematic phase, an isotropic phase, etc., depending on conditions.

As the liquid crystal material, either positive liquid crystal or negative liquid crystal may be used, and an optimum liquid crystal material may be used according to the mode and design to be applied.

In addition, an alignment film can be provided to control the alignment of liquid crystals. Note that when the horizontal electric field method is employed, liquid crystal exhibiting a blue phase without using an alignment film may be used. The blue phase is one of the liquid crystal phases, and is a phase that appears immediately before the cholesteric phase transitions to the isotropic phase when the temperature of the cholesteric liquid crystal is increased. Since the blue phase is expressed only in a narrow temperature range, a liquid crystal composition mixed with a chiral agent of several weight % or more 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. Further, a liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent does not require alignment treatment and has a small viewing angle dependency. In addition, rubbing treatment is not required because an alignment film is not required, so that electrostatic damage caused by rubbing treatment can be prevented, and defects and 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, in particular, 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. As a backlight
It may be a direct type backlight or an edge light type backlight. It is preferable to use a direct type backlight equipped with LEDs (Light Emitting Diodes) because local dimming can be facilitated and contrast can be increased. Further, it is preferable to use an edge-light type backlight because the thickness of the module including the backlight can be reduced.

When a reflective liquid crystal element is used, a polarizing plate is provided on the display surface side. Apart from this,
Placing a light diffusion plate on the display surface side is preferable because visibility can be improved.

Further, when a reflective or transflective liquid crystal element is used, a front light may be provided outside the polarizing plate. As the front light, it is preferable to use an edge light type front light. It is preferable to use a front light equipped with an LED (Light Emitting Diode) because power consumption can be reduced.

In one embodiment of the present invention, the liquid crystal material preferably contains a dichroic dye. note that,
A liquid crystal material containing a dichroic dye is called a guest-host liquid crystal. Specifically, the dichroic dye includes a material having a large absorbance in the long axis direction of the molecule and a material having a small absorbance in the short axis direction orthogonal to the long axis direction. Preferably, a material having a dichroic ratio of 10 or more can be used for the dichroic dye, more preferably a material having a dichroic ratio of 20 or more can be used for the dichroic dye.

For example, azo dyes, anthraquinone dyes, dioxazine dyes, and the like can be used as dichroic dyes. Alternatively, two liquid crystal layers containing homogeneously aligned dichroic dyes,
A structure in which the alignment directions are perpendicular to each other can be used for the layer containing the liquid crystal material. Thereby, light can be easily absorbed in all directions. Alternatively, contrast can be enhanced.

Further, a phase transition type guest/host liquid crystal or a polymer liquid crystal obtained by dispersing droplets containing a guest/host liquid crystal in a polymer may be used as the liquid crystal material.

Here, a structure in which a liquid crystal material of a liquid crystal element contains a dichroic dye will be described with reference to FIG.

27A and 27B are diagrams illustrating the operation of the liquid crystal element 780 of one embodiment of the present invention.

A liquid crystal element 780 shown in FIGS. 27A and 27B includes a pair of electrodes (an electrode 781 and an electrode 782).
), a liquid crystal layer 783 and alignment films 785a and 785b are provided. Also, the liquid crystal layer 78
3 comprises a liquid crystal material LC and a dichroic dye DD. Note that here, the electrode 781 is assumed to be a reflective electrode, and the electrode 782 is assumed to be a translucent electrode.

Note that FIG. 27A is a diagram for explaining the operating state of the liquid crystal layer 783, and FIG. 27B is a diagram for explaining an operating state different from FIG. 27A.

As shown in FIG. 27A, the dichroic dye DD is oriented so as to absorb less light 784 traveling in the thickness direction. For example, an electric field is used to align the liquid crystal material LC used as host material and to control the alignment of the dichroic dye used as guest material. Thereby, the transmitted light can be reflected by the electrode 781 . Therefore, a reflective liquid crystal element can be formed without using a polarizing plate.

Note that when the hybrid display described above is assumed, a light-emitting element is provided below the liquid crystal element 780 . In the case of this structure, the attenuation of the light emitted from the light emitting element can be suppressed by orienting the dichroic dye DD so that the absorption thereof is reduced. Therefore, since the light emitted from the light emitting element is not blocked by the polarizing plate or the like, it is possible to use much of the light emitted from the light emitting element.

Further, as shown in FIG. 27B, the dichroic dye DD is oriented so as to absorb more light 784 traveling in the thickness direction. For example, an electric field is used to align the liquid crystal material LC used as host material and to control the alignment of the dichroic dye used as guest material. As a result, the transmitted light can be absorbed by the dichroic dye DD, and the light incident on the electrode 781 can be weakened. Therefore, a reflective liquid crystal element can be formed without using a polarizing plate.

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

Light-emitting elements include top emission type, bottom emission type, dual emission type, and the like. A conductive film that transmits visible light is used for the electrode on the light extraction side. A conductive film that reflects visible light is preferably used for the electrode on the side 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, which includes a substance with a high hole-injection property, a substance with a high hole-transport property, a hole-blocking material, a substance with a high electron-transport property, a substance with a high electron-injection property, or a bipolar material. A layer containing a substance (a substance having a high electron-transport property and a high hole-transport property) or the like may be further included.

Either a low-molecular-weight compound or a high-molecular-weight compound can be used in the EL layer, and an inorganic compound may be included. Each of the layers constituting the EL layer can be formed by a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, a coating method, or the like.

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 recombine in the EL layer, and the light-emitting substance contained in the EL layer emits light.

When a light-emitting element emitting white light is used as the light-emitting element, the EL layer preferably contains two or more kinds of light-emitting substances. For example, white light emission can be obtained by selecting light-emitting substances such that the light emitted from each of two or more light-emitting substances has a complementary color relationship. for example,
Luminous substances that emit light such as R (red), G (green), B (blue), Y (yellow), O (orange), etc.
or among luminescent substances that emit light containing spectral components of two or more colors selected from among R, G, and B,
It preferably contains two or more. Further, it is preferable to use a light-emitting element in which the spectrum of light emitted from the light-emitting element has two or more peaks within the wavelength range of visible light (eg, 350 nm to 750 nm). Moreover, 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 as well.

The EL layer preferably has a structure in which a light-emitting layer containing a light-emitting material that emits light of one color and a light-emitting layer containing a light-emitting material that emits light of another color are stacked. For example, a plurality of light-emitting layers in the EL layer may be laminated in contact with each other, or may be laminated via a region that does not contain any light-emitting material. For example, a configuration in which a region is provided between a fluorescent-emitting layer and a phosphorescent-emitting layer and contains the same material as the fluorescent-emitting layer or the phosphorescent-emitting layer (e.g., host material, assist material) and does not contain any of the emitting materials. good too. This facilitates fabrication of the light-emitting element and reduces the driving voltage.

Further, the light emitting element may be a single element having one EL layer, or may be a tandem element in which a plurality of EL layers are laminated via a charge generation layer.

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

For the conductive film that reflects visible light, metal materials such as aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or alloys containing these metal materials are used. can be done. Further, lanthanum, neodymium, germanium, or the like may be added to the metal material or alloy. Alternatively, an alloy containing titanium, nickel, or neodymium and aluminum (aluminum alloy) may be used. An alloy containing copper, palladium, magnesium, and silver may also be used. An alloy containing silver and copper is preferred because of its high heat resistance. Furthermore, by stacking a metal film or metal oxide film in contact with the aluminum film or aluminum alloy film, oxidation can be suppressed. Examples of materials for such metal films and metal oxide films include titanium and titanium oxide. Alternatively, a 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. In addition, it can be formed using an ejection method such as an inkjet method, a printing method such as a screen printing method, or a plating method.

In addition, the layer containing the above-described light-emitting layer, a substance with high hole-injection property, a substance with high hole-transport property, a substance with high electron-transport property, a substance with high electron-injection property, a bipolar substance, etc.
Each may have an inorganic compound such as a quantum dot, or a polymer compound (oligomer, dendrimer, polymer, etc.). For example, by using quantum dots in the light-emitting layer, it can function as a light-emitting material.

The quantum dot materials include colloidal quantum dot materials, alloy quantum dot materials,
A core-shell quantum dot material, a core quantum dot material, or the like can be used. Also, materials containing element groups of groups 12 and 16, 13 and 15, or 14 and 16 may be used. or cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium,
Quantum dot materials containing elements such as lead, gallium, arsenic, and aluminum may also be used.

[Adhesion layer]
As the adhesive layer, various curable adhesives such as photocurable adhesives such as ultraviolet curable adhesives, reaction curable adhesives, thermosetting adhesives, and anaerobic adhesives can be used. These adhesives include epoxy resin, acrylic resin, silicone resin, phenol resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, E
VA (ethylene vinyl acetate) resin and the like. In particular, a material with low moisture permeability such as epoxy resin is preferable. Also, a two-liquid mixed type resin may be used. Alternatively, an adhesive sheet or the like may be used.

Moreover, the resin may contain a desiccant. For example, a substance that adsorbs moisture by chemisorption, such as oxides of alkaline earth metals (calcium oxide, barium oxide, etc.) can be used. Alternatively, a substance that adsorbs moisture by physical adsorption, such as zeolite or silica gel, may be used. If a desiccant is contained, it is possible to prevent impurities such as moisture from entering the element, and the reliability of the display panel is improved, which is preferable.

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

[Connection layer]
As the connection layer, an anisotropic conductive film (ACF: Anisotropic Condu
Active Film) and anisotropic conductive paste (ACP: Anisotropic C
conductive paste) or the like can be used.

[Colored layer]
Materials that can be used for the colored layer include metal materials, resin materials, and resin materials containing pigments or dyes.

[Light shielding layer]
Materials that can be used as the light shielding layer include carbon black, titanium black,
Examples include metals, metal oxides, composite oxides containing solid solutions of multiple metal oxides, and the like. The light shielding layer may be a film containing a resin material, or a thin film of an inorganic material such as metal. Alternatively, a laminated film of films containing a material for the colored layer can be used as the light shielding layer. For example, a layered structure of a film containing a material used for a colored layer that transmits light of a certain color and a film containing a material used for a colored layer that transmits light of another color can be used. By using a common material for the colored layer and the light-shielding layer, it is possible to use a common apparatus and to simplify the process, which is preferable.

This embodiment can be implemented by appropriately combining at least part of it with other embodiments described herein.

(Embodiment 5)
In this embodiment, examples of transistors that can be used in place of the transistors described in the above embodiments will be described with reference to drawings.

A display device of one embodiment of the present invention can be manufactured using various types of transistors such as a bottom-gate transistor and a top-gate transistor. Therefore, it is possible to easily replace the material of the semiconductor layer and the transistor structure to be used in accordance with the existing manufacturing line.

<5-1. Bottom-gate transistor>
FIG. 28A1 is a cross-sectional view of a channel-protective transistor 810, which is a type of bottom-gate transistor, in the channel length direction. 28 (A2) (B1) (B2)
) (C1) and (C2) are cross-sectional views of the bottom-gate transistor in the channel length direction.

The transistor 810 is formed over the substrate 771 in FIG. The transistor 810 also has an electrode 746 over the substrate 771 with an insulating layer 772 interposed therebetween. In addition, a semiconductor layer 742 is provided over the electrode 746 with the insulating layer 726 interposed therebetween. Electrode 746 can function as a gate electrode. The insulating layer 726 can function as a gate insulating layer.

In addition, an insulating layer 741 is provided over the channel formation region of the semiconductor layer 742 . Further, an electrode 744 a and an electrode 744 b are provided over the insulating layer 726 in contact with part of the semiconductor layer 742 . Electrode 744a can function as either a source electrode or a drain electrode. Electrode 744b can function as the other of a source electrode or a drain electrode. A portion of the electrode 744 a and a portion of the electrode 744 b are formed over the insulating layer 741 .

The insulating layer 741 can function as a channel protective layer. An insulating layer 74 on the channel forming region
By providing 1, the semiconductor layer 742 can be prevented from being exposed when the electrodes 744a and 744b are formed. Therefore, the channel formation region of the semiconductor layer 742 can be prevented from being etched when the electrodes 744a and 744b are formed. According to one embodiment of the present invention, a transistor with favorable electrical characteristics can be obtained.

In addition, the transistor 810 has an insulating layer 728 over the electrodes 744 a and 744 b and the insulating layer 741 and an insulating layer 729 over the insulating layer 728 .

In the case where an oxide semiconductor is used for the semiconductor layer 742, a material capable of depriving oxygen from part of the semiconductor layer 742 to cause oxygen vacancies is used for at least portions of the electrodes 744a and 744b which are in contact with the semiconductor layer 742. is preferred. A region in which oxygen deficiency occurs in the semiconductor layer 742 has an increased carrier concentration, the region becomes n-type, and becomes an n-type region (n ⁺ layer). Therefore, the region can function as a source region or a drain region.
In the case where an oxide semiconductor is used for the semiconductor layer 742, examples of materials that can deprive the semiconductor layer 742 of oxygen and cause oxygen vacancies include tungsten, titanium, and the like.

An electrode 744 is formed by forming a source region and a drain region in the semiconductor layer 742 .
a and the contact resistance between the electrode 744b and the semiconductor layer 742 can be reduced. Therefore, electrical characteristics of the transistor such as field-effect mobility and threshold voltage can be improved.

In the case of using a semiconductor such as silicon for the semiconductor layer 742 , the semiconductor layer 742 and the electrode 744
A layer functioning as an n-type semiconductor or a p-type semiconductor is preferably provided between a and between the semiconductor layer 742 and the electrode 744b. A layer that functions as an n-type semiconductor or a p-type semiconductor can function as the source or drain region of a transistor.

The insulating layer 729 is preferably formed using a material that has a function of preventing or reducing diffusion of impurities from the outside into the transistor. Note that the insulating layer 729 can be omitted as necessary.

A transistor 811 illustrated in FIG. 28A2 is different from the transistor 810 in that an electrode 723 that can function as a back gate electrode is provided over an insulating layer 729 . Electrode 723 can be formed with a material and method similar to electrode 746 .

In general, the back gate electrode is formed of a conductive layer and arranged so as to sandwich a channel formation region of a semiconductor layer between the gate electrode and the back gate electrode. Therefore, the back gate electrode can function similarly to the gate electrode. The potential of the back gate electrode may be the same as that of the gate electrode, the ground potential (GND potential), or any other potential. In addition, by changing the potential of the back gate electrode independently of the potential of the gate electrode, the threshold voltage of the transistor can be changed.

29A1 shows a cross-sectional view of the transistor 810 in the channel width direction, FIG. 29A2 shows a cross-sectional view of the transistor 811 in the channel width direction, and FIG. 29A shows a cross-sectional view of the transistor 820 in the channel width direction. B1), a cross-sectional view of the transistor 821 in the channel width direction is shown in FIG. 29B2, a cross-sectional view of the transistor 825 in the channel width direction is shown in FIG.
FIG. 29C2 shows a cross-sectional view of the transistor 826 in the channel width direction.

In the structures shown in FIGS. 29B2 and 29C2, the gate electrode and the back gate electrode are connected and have the same potential.

29B2 and 29C2, the semiconductor layer 742 is sandwiched between the gate electrode and the back gate electrode. In addition, the length of each of the gate electrode and the back gate electrode in the channel width direction is longer than the length of the semiconductor layer 742 in the channel width direction. It is covered with a gate electrode or a back gate electrode with 729 interposed therebetween. With this configuration,
A semiconductor layer 742 included in the transistor can be electrically surrounded by electric fields of the gate electrode and the back gate electrode.

A device structure of a transistor that electrically surrounds a semiconductor layer 742 in which a channel region is formed by an electric field of a gate electrode and a back gate electrode, such as the transistor 821 or the transistor 826, is called a surrounded channel (S-channel).
) structure.

With the S-channel structure, an electric field for inducing a channel can be effectively applied to the semiconductor layer 742 by one or both of the gate electrode and the back gate electrode, so that the current driving capability of the transistor is improved. , it is possible to obtain high on-current characteristics. In addition, since the on current can be increased, the transistor can be miniaturized. In addition, the S-channel structure can increase the mechanical strength of the transistor.

Both the electrode 746 and the electrode 723 can function as gate electrodes. Thus, each of the insulating layers 726, 728, and 729 can function as a gate insulating layer. Note that the electrode 723 may be provided between the insulating layer 728 and the insulating layer 729 .

Note that when one of the electrode 746 and the electrode 723 is called a "gate electrode", the other is called a "back gate electrode". For example, in the transistor 811, when the electrode 723 is called the "gate electrode", the electrode 746 is called the "back gate electrode". Further, when the electrode 723 is used as a "gate electrode," the transistor 811 can be considered to be a type of top-gate transistor. Further, one of the electrode 746 and the electrode 723 is sometimes referred to as a "first gate electrode" and the other is referred to as a "second gate electrode".

By providing the electrode 746 and the electrode 723 with the semiconductor layer 742 interposed therebetween, the electrode 7
46 and the electrode 723 are set at the same potential, the area through which carriers flow in the semiconductor layer 742 becomes larger in the film thickness direction, so that the movement amount of carriers increases. As a result,
As the on current of the transistor 811 increases, the field effect mobility increases.

Therefore, the transistor 811 is a transistor having a large on-current with respect to its occupied area. That is, the area occupied by the transistor 811 can be reduced with respect to the required on-current. According to one embodiment of the present invention, the area occupied by the transistor can be reduced. Therefore, according to one embodiment of the present invention, a highly integrated semiconductor device can be achieved.

In addition, since the gate electrode and the back gate electrode are formed of conductive layers, they have a function of preventing an electric field generated outside the transistor from acting on the semiconductor layer in which the channel is formed (particularly an electric field shielding function against static electricity). . By forming the back gate electrode larger than the semiconductor layer and covering the semiconductor layer with the back gate electrode, the electric field shielding function can be enhanced.

In addition, by forming the back gate electrode using a light-blocking conductive film, light can be prevented from entering the semiconductor layer from the back gate electrode side. Therefore, photodegradation of the semiconductor layer can be prevented, and deterioration of electrical characteristics such as shift of the threshold voltage of the transistor can be prevented.

According to one embodiment of the present invention, a highly reliable transistor can be achieved. Moreover, a highly reliable semiconductor device can be realized.

FIG. 28B1 shows a cross-sectional view of a channel-protective transistor 820 which is one of bottom-gate transistors. The transistor 820 has almost the same structure as the transistor 810 except that the insulating layer 741 covers the edge of the semiconductor layer 742 .
In addition, the semiconductor layer 742 and the electrode 744a are electrically connected to each other through an opening formed by selectively removing a part of the insulating layer 741 overlapping with the semiconductor layer 742 . Also, the semiconductor layer 742
In another opening formed by selectively removing a part of the insulating layer 741 overlapping with the semiconductor layer 741
42 and the electrode 744b are electrically connected. A region of the insulating layer 741 overlapping with the channel formation region can function as a channel protective layer.

A transistor 821 illustrated in FIG. 28B2 is different from the transistor 820 in that an electrode 723 that can function as a back gate electrode is provided over an insulating layer 729 .

By providing the insulating layer 741, the semiconductor layer 742 can be prevented from being exposed when the electrodes 744a and 744b are formed. Therefore, thinning of the semiconductor layer 742 can be prevented when the electrodes 744a and 744b are formed.

In the transistors 820 and 821 , the distance between the electrodes 744 a and 746 and the distance between the electrodes 744 b and 746 are longer than those of the transistors 810 and 811 . Therefore, parasitic capacitance generated between the electrode 744a and the electrode 746 can be reduced. In addition, parasitic capacitance generated between the electrodes 744b and 746 can be reduced. According to one embodiment of the present invention, a transistor with favorable electrical characteristics can be realized.

A transistor 825 illustrated in FIG. 28C1 is a channel-etched transistor which is one of bottom-gate transistors. Transistor 825 is isolated from insulating layer 741
Electrodes 744a and 744b are formed without using . Therefore, part of the semiconductor layer 742 that is exposed when the electrodes 744a and 744b are formed may be etched.
On the other hand, since the insulating layer 741 is not provided, the productivity of transistors can be improved.

A transistor 826 illustrated in FIG. 28C2 is different from the transistor 825 in that an electrode 723 that can function as a back gate electrode is provided over an insulating layer 729 .

<5-2. Top-gate transistor>
FIG. 30A1 shows a cross-sectional view of a transistor 830, which is a type of top-gate transistor, in the channel length direction. The transistor 830 has the semiconductor layer 7 over the insulating layer 772 .
42 , and has an electrode 744 a in contact with part of the semiconductor layer 742 and an electrode 744 b in contact with part of the semiconductor layer 742 over the semiconductor layer 742 and the insulating layer 772 .
, an electrode 744a, and an insulating layer 726 on the electrode 744b, and an electrode 726 on the insulating layer 726.
46. 30A2, 30A3, 30B1, and 30B2 are cross-sectional views of top-gate transistors in the channel length direction.

Transistor 830 reduces parasitic capacitance between electrodes 746 and 744a and between electrodes 746 and 744b because electrodes 746 and 744a and electrodes 746 and 744b do not overlap. be able to.
Further, after the electrode 746 is formed, impurity regions 755 can be introduced into the semiconductor layer 742 using the electrode 746 as a mask, so that impurity regions can be formed in the semiconductor layer 742 in a self-aligned manner ( See FIG. 30 (A3)). According to one aspect of the invention,
A transistor with favorable electrical characteristics can be realized.

Note that the impurity 755 can be introduced using an ion implantation apparatus, an ion doping apparatus, or a plasma treatment apparatus.

As the impurity 755, for example, at least one element selected from group 13 elements and group 15 elements can be used. In the case where an oxide semiconductor is used for the semiconductor layer 742, at least one element selected from a rare gas, hydrogen, and nitrogen can be used as the impurity 755. FIG.

A transistor 831 illustrated in FIG. 30A2 is different from the transistor 830 in that an electrode 723 and an insulating layer 727 are included. The transistor 831 has an electrode 723 formed over the insulating layer 772 and an insulating layer 727 formed over the electrode 723 . The electrode 723 is
It can function as a back gate electrode. Therefore, the insulating layer 727 can function as a gate insulating layer. The insulating layer 727 can be formed using a material and a method similar to those of the insulating layer 726 .

Similar to transistor 811, transistor 831 is a transistor that has a large on-current relative to its area of occupation. That is, the area occupied by the transistor 831 can be reduced with respect to the required on-current. According to one embodiment of the present invention, the area occupied by the transistor can be reduced. Therefore, according to one embodiment of the present invention, a highly integrated semiconductor device can be achieved.

A transistor 840 illustrated in FIG. 30B1 is a top-gate transistor.
is one. The transistor 840 is different from the transistor 830 in that the semiconductor layer 742 is formed after the electrodes 744a and 744b are formed. A transistor 841 illustrated in FIG. 30B2 is different from the transistor 840 in that an electrode 723 and an insulating layer 727 are included. In the transistors 840 and 841, the semiconductor layer 74
2 is formed over electrode 744a and another portion of semiconductor layer 742 is formed over electrode 744b.

Similar to transistor 811, transistor 841 is a transistor that has a large on-current relative to its area of occupation. That is, the area occupied by the transistor 841 can be reduced with respect to the required on-current. According to one embodiment of the present invention, the area occupied by the transistor can be reduced. Therefore, according to one embodiment of the present invention, a highly integrated semiconductor device can be achieved.

A cross-sectional view of the transistor 830 shown in FIG. 30A1 in the channel width direction is shown in FIG.
A1) shows a cross-sectional view in the channel width direction of the transistor 831 shown in FIG.
3A2 is a cross-sectional view in the channel width direction of the transistor 840 illustrated in FIG. 30B1.
1B1, and FIG. 31B2 shows a cross-sectional view of the transistor 841 shown in FIG. 30B2 in the channel width direction.

Note that the transistors 831 and 841 are the S-ch transistors described above.
It is an channel structure. However, the present invention is not limited to this, and the transistors 831 and 841 do not have to have an S-channel structure.

Next, FIGS. 32 and 33 show top-gate transistors that are different from the transistors shown in FIGS.

FIG. 32A1 is a cross-sectional view of the transistor 842 in the channel length direction.
2) is a cross-sectional view of the transistor 843 in the channel length direction, FIG. 32B1 is a cross-sectional view of the transistor 844 in the channel length direction, and FIG.
32C1 is a cross-sectional view of the transistor 846 in the channel length direction, and FIG. 32C2 is a cross-sectional view of the transistor 847 in the channel length direction.

FIG. 32A3 is a cross-sectional view illustrating a manufacturing process of the transistor 842 in the channel length direction.

In the transistor 842 illustrated in FIG. 32A1, the electrode 744 is formed after the insulating layer 729 is formed.
It differs from the transistor 830 and the transistor 840 in that a and an electrode 744b are formed. The electrodes 744 a and 744 b are electrically connected to the semiconductor layer 742 through openings formed in the insulating layers 728 and 729 .

In addition, a part of the insulating layer 726 that does not overlap with the electrode 746 is removed, and an impurity 755 is introduced into the semiconductor layer 742 using the electrode 746 and the remaining insulating layer 726 as a mask, so that the semiconductor layer 742 is self-aligned ( Impurity regions can be formed in a self-aligned manner (
See FIG. 32 (A3)). Transistor 842 has regions where insulating layer 726 extends beyond the edge of electrode 746 . When introducing the impurity 755 into the semiconductor layer 742 , the semiconductor layer 74
The impurity concentration of the region into which the impurity 755 is introduced through the insulating layer 726 of No. 2 is equal to that of the insulating layer 726
becomes smaller than the region into which the impurity 755 is introduced without intervening. Therefore, the semiconductor layer 742 has an LDD (Lightly Doped Drain) in a region that does not overlap with the electrode 746 .
A region is formed.

A transistor 843 illustrated in FIG.
42 different. Transistor 843 has electrode 723 formed over substrate 771,
It overlaps with the semiconductor layer 742 with the insulating layer 772 interposed therebetween. The electrode 723 can function as a back gate electrode.

Alternatively, the insulating layer 726 may be removed from a region that does not overlap with the electrode 746, like the transistor 844 in FIG. 32B1 and the transistor 845 in FIG. 32B2. Alternatively, the insulating layer 726 may be left as in the transistor 846 in FIG. 32C1 and the transistor 847 in FIG. 32C2.

For the transistors 842 to 847 as well, the electrode 74 is formed after the electrode 746 is formed.
6 as a mask, an impurity 755 is introduced into the semiconductor layer 742 to form the semiconductor layer 74
Impurity regions can be formed in 2 in a self-aligned manner. According to one embodiment of the present invention, a transistor with favorable electrical characteristics can be obtained. Further, according to one embodiment of the present invention, a highly integrated semiconductor device can be achieved.

A cross-sectional view in the channel width direction of the transistor 842 shown in FIG. 32A1 is shown in FIG.
A1) shows a cross-sectional view in the channel width direction of the transistor 843 shown in FIG.
(A2) is a cross-sectional view of the transistor 844 in the channel width direction shown in FIG.
3B1 is a cross-sectional view of the transistor 845 illustrated in FIG. 32B2 in the channel width direction, and FIG. 33C is a cross-sectional view of the transistor 846 illustrated in FIG. C1) and FIG. 33C2 show cross-sectional views of the transistor 847 shown in FIG. 32C2 in the channel width direction.

Note that the transistors 843, 845, and 847 each have the S-channel structure described above. However, the present invention is not limited to this, and the transistors 843, 845, and 847 do not have to have an S-channel structure.

A modification of the transistor 845 shown in FIGS. 32B2 and 33B2 is shown in FIG.
(A1) and (A2). FIG. 34A1 is a cross-sectional view of the transistor 845A in the channel length direction, and FIG. 34A2 is a cross-sectional view of the transistor 845A in the channel width direction.

A transistor 845A illustrated in FIGS.
is different from that of the transistor 845, and the position of the transistor 845 is otherwise the same.
is the same as

This embodiment can be implemented by appropriately combining at least part of it with other embodiments described herein.

(Embodiment 6)
In this embodiment, a display module that can be manufactured using one embodiment of the present invention will be described.

<6. Display module>
A display module 6000 shown in FIG. 35A includes an upper cover 6001 and a lower cover 60
02, a display panel 6006 connected to the FPC 6005, a frame 6009, a printed circuit board 6010, and a battery 6011 are provided.

For example, a display device manufactured using one embodiment of the present invention can be used for the display panel 6006 . Thereby, the display module can be manufactured with a high yield.

The shape and dimensions of the upper cover 6001 and the lower cover 6002 can be appropriately changed according to the size of the display panel 6006 .

The frame 6009 has a function of protecting the display panel 6006 as well as a function as an electromagnetic shield for blocking electromagnetic waves generated by the operation of the printed circuit board 6010 . The frame 6009 may also function as a heat sink.

The printed circuit board 6010 has a power supply circuit, a signal processing circuit for outputting a video signal and a clock signal. A power supply for supplying power to the power supply circuit may be an external commercial power supply, or may be a power supply using a separately provided battery 6011 . The battery 6011 can be omitted when a commercial power source is used.

Further, the display module 6000 may be additionally provided with members such as a polarizing plate, a retardation plate, and a prism sheet.

Further, the display panel 6006 has a touch sensor as an input device as described in Embodiment 1. FIG. As the touch sensor, a resistive film type or a capacitive type may be used.

Alternatively, the structure shown in FIG. 35B may be employed without providing the touch sensor on the display panel 6006 . FIG. 35B is a schematic cross-sectional view of a display module 6000 including an optical touch sensor. Also, although not shown, a capacitive touch sensor and an optical touch sensor may be used in combination.

A display module 6000 illustrated in FIG. 35B includes a light-emitting portion 6015 and a light-receiving portion 6016 provided over a printed circuit board 6010 . Also, the upper cover 6001 and the lower cover 60
02 has a pair of light guide portions (light guide portion 6017a, light guide portion 6017b).

For the upper cover 6001 and the lower cover 6002, for example, plastic or the like can be used. Also, the upper cover 6001 and the lower cover 6002 are each thin (for example, 0.
5 mm or more and 5 mm or less). Therefore, it is possible to make the display module 6000 extremely lightweight. Moreover, the upper cover 6001 and the lower cover 6 can be manufactured with a small amount of material.
002, the manufacturing cost can be reduced.

A display panel 6006 is provided so as to overlap a printed circuit board 6010 and a battery 6011 with a frame 6009 interposed therebetween. The display panel 6006 and the frame 6009 are fixed to the light guide portions 6017a and 6017b.

The light 6018 emitted from the light emitting portion 6015 is transmitted to the display panel 60 by the light guide portion 6017a.
06, and reaches the light receiving portion 6016 through the light guide portion 6017b. For example, a touch operation can be detected when the light 6018 is blocked by a sensing object such as a finger or a stylus.

A plurality of light emitting units 6015 are provided, for example, along two adjacent sides of the display panel 6006 . A plurality of light receiving portions 6016 and light emitting portions 6015 are provided at both ends of the display panel 6006 . Accordingly, it is possible to acquire information on the position where the touch operation is performed.

A light source such as an LED element can be used for the light emitting unit 6015, for example. In particular, as the light emitting unit 6015, it is preferable to use a light source that emits infrared rays that are invisible to the user and harmless to the user.

The light receiving unit 6016 can use a photoelectric element that receives light emitted by the light emitting unit 6015 and converts it into an electric signal. Preferably, a photodiode capable of receiving infrared rays can be used.

A member that transmits at least the light 6018 can be used as the light guide portion 6017a and the light guide portion 6017b. By using the light guide portion 6017a and the light guide portion 6017b, the light emitting portion 6015 and the light receiving portion 6016 can be arranged below the display panel 6006, and external light reaches the light receiving portion 6016, causing the touch sensor to malfunction. can be suppressed. In particular, it is preferable to use a resin that absorbs visible light and transmits infrared light. Thereby, malfunction of the touch sensor can be suppressed more effectively.

This embodiment can be implemented by appropriately combining at least part of it with other embodiments described herein.

(Embodiment 7)
In this embodiment, electronic devices to which the display device of one embodiment of the present invention can be applied are described in FIGS.
Description will be made with reference to FIG.

<7-1. Electronic device 1>
First, an example of an electronic device will be described with reference to FIGS. 36 and 37. FIG. The display device of one embodiment of the present invention can achieve high visibility regardless of the intensity of external light. Therefore, it can be suitably used for portable electronic devices, wearable electronic devices (wearable devices), electronic book terminals, television devices, digital signage, and the like.

36A and 36B show an example of a portable information terminal 1800. FIG. Portable information terminal 1800
includes a housing 1801, a housing 1802, a display portion 1803, a display portion 1804, and a hinge portion 18
05, etc.

The housing 1801 and the housing 1802 are connected by a hinge portion 1805 . Portable information terminal 1
800 can open housings 1801 and 1802 as shown in FIG. 36(B) from the folded state as shown in FIG. 36(A).

For example, document information can be displayed on the display units 1803 and 1804.
It can also be used as an electronic book terminal. Still images and moving images can also be displayed on the display portions 1803 and 1804 .

As described above, the portable information terminal 1800 can be folded when being carried.
Excellent versatility.

Note that the housing 1801 and the housing 1802 may have a power button, an operation button, an external connection port, a speaker, a microphone, and the like.

FIG. 36C shows an example of a portable information terminal. Portable information terminal 1810 shown in FIG.
includes a housing 1811, a display portion 1812, operation buttons 1813, an external connection port 1814, a speaker 1815, a microphone 1816, a camera 1817, and the like.

A display device of one embodiment of the present invention is provided in the display portion 1812 .

A mobile information terminal 1810 includes a touch sensor in a display portion 1812 . Any operation such as making a call or inputting characters can be performed by touching the display portion 1812 with a finger, a stylus, or the like.

In addition, by operating the operation button 1813, the power is turned on and off, and the display unit 1812 is turned on.
You can switch the type of image displayed in the . For example, it is possible to switch from the mail creation screen to the main menu screen.

In addition, by providing a detection device such as a gyro sensor or an acceleration sensor inside the mobile information terminal 1810, the orientation (vertical or horizontal) of the mobile information terminal 1810 is determined, and the display unit 181
2 can be automatically switched. In addition, switching of the screen display direction can be performed by touching the display portion 1812, operating the operation button 1813, voice input using the microphone 1816, or the like.

The mobile information terminal 1810 has one or more functions selected from, for example, a telephone, notebook, information viewing device, and the like. Specifically, it can be used as a smartphone.
Personal digital assistant 1810 is capable of executing various applications such as mobile phone, e-mail, text viewing and composition, music playback, video playback, Internet communication, and games, for example.

FIG. 36(D) shows an example of a camera. The camera 1820 includes a housing 1821, a display unit 18
22, an operation button 1823, a shutter button 1824, and the like. Also camera 1820
A detachable lens 1826 is attached to the .

The display portion 1822 includes the display device of one embodiment of the present invention.

Here, the camera 1820 has a configuration in which the lens 1826 can be removed from the housing 1821 and replaced, but the lens 1826 and the housing may be integrated.

The camera 1820 can capture still images or moving images by pressing the shutter button 1824 . Further, the display portion 1822 has a function as a touch panel, and an image can be captured by touching the display portion 1822 .

Note that the camera 1820 can be separately equipped with a strobe device, a viewfinder, and the like. Alternatively, these may be incorporated in housing 1821 .

FIG. 37A shows a television set 1830. FIG. A television set 1830 includes a display portion 1831, a housing 1832, speakers 1833, and the like. Furthermore, it can have an LED lamp, an operation key (including a power switch or an operation switch), connection terminals, various sensors, a microphone, and the like.

Also, the television device 1830 can be operated by a remote controller 1834 .

Broadcast radio waves that can be received by the television device 1830 include terrestrial waves and radio waves transmitted from satellites. Broadcast radio waves include analog broadcasting, digital broadcasting, and the like, as well as broadcasting of video and audio, or audio only. For example, UHF band (about 30
0 MHz to 3 GHz) or VHF band (30 MHz to 300 MHz). Also, for example, by using a plurality of data received in a plurality of frequency bands, the transfer rate can be increased and more information can be obtained. Accordingly, an image having a resolution higher than full high definition can be displayed on the display portion 1831 . For example, images having resolutions of 4K, 8K, 16K, or higher can be displayed.

In addition, the Internet, LAN (Local Area Network), Wi-F
An image to be displayed on the display unit 1831 may be generated using broadcast data transmitted by data transmission technology via a computer network such as i (registered trademark).
At this time, television device 1830 may not have a tuner.

FIG. 37(B) shows a digital signage 1840 attached to a cylindrical post 1842. FIG. The digital signage 1840 has a display section 1841 .

As the display portion 1841 is wider, the amount of information that can be provided at one time can be increased. Also, the wider the display portion 1841, the more conspicuous it is, and the more effective the advertisement can be, for example.

By applying a touch panel to the display portion 1841, not only an image or a moving image can be displayed on the display portion 1841 but also the user can intuitively operate the display portion 1841, which is preferable. Further, when used for providing information such as route information or traffic information, usability can be enhanced by intuitive operation.

FIG. 37C shows a notebook personal computer 1850 . A personal computer 1850 includes a display portion 1851, a housing 1852, a touch pad 1853, a connection port 1854, and the like.

A touch pad 1853 functions as a pointing device, an input means such as a pen tablet, and can be operated with a finger, a stylus, or the like.

A display element is incorporated in the touch pad 1853 . As shown in FIG. 37C, by displaying input keys 1855 on the surface of the touch pad 1853, the touch pad 1853 can be used as a keyboard. At this time, a vibration module may be incorporated in the touch pad 1853 in order to realize a tactile sensation by vibration when the input key 1855 is touched.

<7-2. Electronic device 2>
Next, an example of an electronic device will be described with reference to FIGS. 38 and 39. FIG. FIG. 38 shows a foldable electronic device.

An electronic device 920 shown in FIG.
A flexible display 922 is provided over 21b.

In FIG. 38, when the housings 921a and 921b are opened, the display unit 922 is held in a greatly curved form. For example, the display unit 922 can be held with a radius of curvature of 1 mm or more and 50 mm or less, preferably 5 mm or more and 30 mm or less.
In part of the display portion 922, pixels are arranged continuously from the housing 921a to the housing 921b, so that curved display can be performed.

Hinge 923 preferably has a locking mechanism so that when housing 921a and housing 921b are opened, these angles do not become larger than a predetermined angle.
For example, the angle at which the lock is applied (does not open further) is preferably 90 degrees or more and less than 180 degrees, typically 90 degrees, 120 degrees, 135 degrees, 160 degrees, or 175 degrees. be able to. This can improve convenience, safety, and reliability.

Since the hinge 923 has the locking mechanism described above, it is possible to prevent damage to the display section 922 without applying excessive force to the display section 922 . Therefore, a highly reliable electronic device can be realized.

39A and 39B show an electronic device 950 that functions as a portable game machine or a tablet information terminal. Note that the electronic device 950 can be folded in two to improve portability. FIG. 39A is a perspective view of the state in which it is folded in two, and FIG. 12 is a perspective view of the electronic device 950 when it is spread about 160° to 175°;

An electronic device 950 includes a housing 952a, a housing 952b, a display portion 954, a hinge portion 953, and the like. Note that the display area of the display portion 954 included in the electronic device 950 is not rectangular, but has a shape such that only the area where the hinge portion 953 is positioned has a smaller display area.

In addition, the display portion 954 has a convex portion on its surface. Further, the display portion 954 has a flat surface in a region overlapping with the housings 952a and 952b and a curved surface in a region overlapping with the hinge portion 953 .

FIG. 40A shows a perspective view of an electronic device 950 that is different from FIG. 39B. again,
FIG. 40B is a side view of the electronic device 950 shown in FIG. 40A.

FIG. 40A is a perspective view of a structure in which projections are provided on the surface of the display portion 954 of the electronic device 950 shown in FIG. 39B.

As shown in FIG. 40A, the display portion 954 has a plurality of convex portions 954a. Although FIG. 40A illustrates a configuration in which a plurality of protrusions 954a are arranged, the configuration is not limited to this, and a single protrusion 954a may be provided.

The convex portion 954a has a function of allowing the user to recognize the position. For example, since the display portion 954 includes a touch sensor, an operation such as an input can be performed on the electronic device 950 by operating the display portion 954 . However, in the case of a configuration in which the convex portion 954a is not provided, the operation location cannot be known unless the display portion 954 is viewed. On the other hand, the convex portion 9
54a, it is possible to recognize the operation place by simply touching the convex portion 954a provided on the display portion 954 without visually recognizing the display portion 954, and to easily perform operations such as input. can be done.

In other words, the electronic device 950 shown in FIG. 40A has a display portion 954 and a convex portion 954a provided on the display portion 954. By touching the convex portion 954a, an input is made to the display portion 954. It has a function that can

Note that the provision of the convex portion 954a eliminates the need to provide a physical button used for a game or the like, which is preferable because various materials used for the physical button can be reduced.

Moreover, it is preferable that the projections 954a also serve as projections of the anti-glare pattern 13c of the antireflection layer shown in FIGS. 2C and 2E, for example. For example, anti-glare pattern 1
Each projection 3c is formed with a grain size of 1 μm or more and 100 μm or less, and a plurality of projections of the anti-glare pattern 13c are densely packed in the region of the projection 954a, whereby the projection 954a can be formed. However, the configuration of the convex portion 954a is not limited to this, and a structural body may be formed of a resin material such as acrylic or polyimide and formed on the display portion 954 in a size that can be recognized by the user. Also, if the protrusions 954a can be formed without assembling a plurality of protrusions of the anti-glare pattern 13c, a single protrusion may be used. In this case, silica particles having a size that can be recognized by the user may be provided on the display portion 954 .

Further, as shown in FIG. 40B, the display portion 954 has a convex portion 954a and a curved surface.
FIG. 40B is a side view of the electronic device 950, in which a region 961 surrounded by dotted lines and a region 962 surrounded by dotted lines are enlarged.

A region 961 is an enlarged side view of the convex portion 954 a , and a region 962 is an enlarged view of the display portion 954 near the hinge portion 953 .

As shown in a region 961, it is preferable that the convex portion 954a protrudes more than the housing 952b because it improves the operability. Further, as shown in region 962 , display portion 954 preferably has a shape having a curved surface near hinge portion 953 . When the display portion 954 has a curved surface, the display portion 954 in the region overlapping with the housing 952a and the display portion 954 in the region overlapping with the housing 952b can be continuously viewed. In addition, since the display portion 954 has a curved surface, the display portion 954 is not bent, and the reliability of the display portion 954 can be improved.

Further, it is preferable that the housing 952a, the housing 952b, and the hinge section 953 have a configuration in which the curved surface portion of the display section 954 can be accommodated. In other words, it is preferable that the housing 952a, the housing 952b, and the hinge portion 953 have a region in which the display portion 954 can be accommodated.

This embodiment can be implemented by appropriately combining at least part of it with other embodiments described herein.

10 display device 11 substrate 12 substrate 13 antireflection layer 13a dielectric layer 13b dielectric layer 13c antiglare pattern 13d film 20 layer 21 element layer 21a FET layer 21b LC layer 21b_LC LC layer 21c OLED layer 22 element layer 23 light diffusion plate 25 input Device 25a Input device 25b Polarizing plate 26 Adhesive layer 26a Adhesive layer 30 Drive circuit 30a Drive circuit 30b Drive circuit 31 FPC
32 FPCs
33a Wiring 33b Wiring 33c Wiring 33d Wiring 35 Liquid crystal element 36 Pixel circuit 40 Pixel array 45 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 101 Region 102 Region 106 Insulation Film 117 Insulating layer 121 Insulating layer 131 Colored layer 132 Light shielding layer 133a Alignment film 133b Alignment film 134 Colored layer 141 Adhesive layer 142 Adhesive layer 161 Substrate 161a Substrate 161b Substrate 162 Separation layer 162a Separation layer 162b Separation layer 163 Layer to be peeled 163a To be peeled Layer 163b Layer to be separated 164 Insulating layer 164a Insulating layer 165 Opening 166 Insulating layer 167 Polarizing plate 168 Substrate 169 Adhesive layer 170 Conductive layer 171 Wiring 171a Conductive layer 171b Dark layer 172 Wiring 172a Conductive layer 172b Dark layer 173 Wiring 173a Conductive layer 173b Dark layer 174 Wiring 174a Conductive layer 174b Conductive layer 176 Adhesive layer 179 Conductive layer 179a Conductive layer 179b Conductive layer 180 Insulating layer 180a Insulating layer 181 Light shielding layer 181a Light shielding layer 182 Colored layer 182a Colored layer 183 Insulating layer 183a Insulating layer 184 Adhesive layer 185 Light diffusion plate 186 Adhesive layer 187 Adhesive layer 191 Conductive layer 192 EL layer 193a Conductive layer 193b Conductive layer 201 Transistor 204 Connection 205 Transistor 206 Transistor 207 Connection 211 Insulating layer 212 Insulating layer 213 Insulating layer 214 Insulating layer 215 Insulating layer 216 Insulation 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 Connector 251 Opening 252 Connection section 300 Display panel 311 Electrode 311a Conductive layer 311b Conductive layer 312 Liquid crystal 313 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 section 364 Circuit 365 Wiring 366 Touch sensor 372 FPC
373 IC
400 Display device 410 Pixel 451 Opening 501B Insulating film 560 Substrate 571 Insulating film 572 Insulating film 575 Proximity sensor 576 Opening 723 Electrode 726 Insulating layer 727 Insulating layer 728 Insulating layer 729 Insulating layer 741 Insulating layer 742 Semiconductor layer 744a Electrode 744b Electrode 746 Electrode 755 impurity 771 substrate 772 insulating layer 780 liquid crystal element 781 electrode 782 electrode 783 liquid crystal layer 784 light 785a alignment film 785b alignment film 810 transistor 811 transistor 820 transistor 821 transistor 825 transistor 826 transistor 830 transistor 831 transistor 840 transistor 841 transistor 842 transistor 843 transistor 844 Transistor 845 Transistor 845A Transistor 846 Transistor 847 Transistor 920 Electronic device 921a Housing 921b Housing 922 Display portion 923 Hinge 950 Electronic device 952a Housing 952b Housing 953 Hinge portion 954 Display portion 954a Projecting portion 961 Region 962 Region 1800 Portable information terminal 1801 Housing 1802 Housing 1803 Display 1804 Display 1805 Hinge 1810 Portable information terminal 1811 Housing 1812 Display 1813 Operation button 1814 External connection port 1815 Speaker 1816 Microphone 1817 Camera 1820 Camera 1821 Housing 1822 Display 1823 Operation button 1824 Shutter Button 1826 Lens 1830 Television device 1831 Display unit 1832 Housing 1833 Speaker 1834 Remote controller 1840 Digital signage 1841 Display unit 1842 Column 1850 Personal computer 1851 Display unit 1852 Housing 1853 Touch pad 1854 Connection port 1855 Input key 6000 Display module 6001 Top Cover 6002 Lower cover 6005 FPC
6006 display panel 6009 frame 6010 printed circuit board 6011 battery 6015 light emitting section 6016 light receiving section 6017a light guide section 6017b light guide section 6018 light

Claims (2)

A display device comprising a first substrate, a second substrate, a first display element, a second display element, and an input device,
The first substrate has a part of the first display element and the second display element,
The second substrate has the input device,
The first display element and the second display element are
provided between the first surface of the first substrate and the first surface of the second substrate;
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, wherein an antireflection layer is provided on a second surface of the second substrate that faces the first surface. In claim 1,
The display device, wherein the first display element and the second display element are provided in the same pixel unit.

Images