Display device

Abstract

To provide a liquid crystal display with a high aperture ratio, and to provide a liquid crystal display with low power consumption.SOLUTION: A display has a liquid crystal element, a transistor, scan lines, and signal lines. The liquid crystal element has a pixel electrode, a liquid crystal layer, and a common electrode. The scan line and signal line are each electrically connected with the transistor. The scan line and signal line each have a metal layer. The transistor is electrically connected with the pixel electrode. A semiconductor layer of the transistor has a first metal oxide layer and a second metal oxide layer laminated thereon. The first metal oxide layer has an area with lower crystallinity than that of the second metal oxide layer. The transistor has a first area connected with the pixel electrode. The pixel electrode, common electrode, and first area have a function to transmit visible light. The visible light is transmitted through the first area and liquid crystal element and emitted to the outside of the display.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] One embodiment of the present invention relates to a liquid crystal display device, a display module, and an electronic device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the semiconductor device include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, Input devices (e.g., touch sensors, etc.), input / output devices (e.g., touch panels, etc.), These driving methods and manufacturing methods can be given as examples. [Background technology]

[0003] It is used in many flat panel displays such as liquid crystal displays and light emitting displays. The transistors are made of amorphous silicon, single crystal silicon, or The semiconductor device is made of silicon semiconductor such as polycrystalline silicon. Transistors that use conductors are also used in integrated circuits (ICs).

[0004] In recent years, metal oxides that exhibit semiconducting properties have been used in transistors instead of silicon semiconductors. In this specification, metal oxides that exhibit semiconducting properties are referred to as oxide semiconductors. For example, Patent Documents 1 and 2 describe the following as oxide semiconductors: A transistor using zinc oxide or In-Ga-Zn oxide is manufactured. A technique for using a transistor as a switching element for a pixel of a display device has been disclosed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2007-123861 A [Patent Document 2] JP 2007-96055 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of one embodiment of the present invention is to provide a liquid crystal display device with a high aperture ratio. An object of one embodiment of the present invention is to provide a liquid crystal display device with low power consumption. Another object of one embodiment of the present invention is to provide a high-definition liquid crystal display device. An object of one embodiment of the present invention is to provide a highly reliable liquid crystal display device.

[0007] Note that the description of these problems does not preclude the existence of other problems. However, it is not necessary to solve all of these problems. It is possible to extract other issues from the description in the section. [Means for solving the problem]

[0008] One embodiment of the present invention is a display device including a liquid crystal element, a transistor, a scan line, and a signal line. The liquid crystal element has a pixel electrode, a liquid crystal layer, and a common electrode. The scanning lines and the signal lines are The scanning lines and the signal lines are each electrically connected to a transistor. The transistor is electrically connected to the pixel electrode. The first metal oxide layer and the second metal oxide layer are laminated. The metal oxide layer 2 has a region having a lower crystallinity than the metal oxide layer 2. The transistor is connected to a pixel electrode. The pixel electrode, the common electrode, and the first region have a function of transmitting visible light. Visible light is transmitted through the first region and the liquid crystal element and emitted to the outside of the display device. do.

[0009] One embodiment of the present invention is a display device including a liquid crystal element, a transistor, a scan line, and a signal line. The liquid crystal element has a pixel electrode, a liquid crystal layer, and a common electrode. The scanning lines and the signal lines are The scanning lines and the signal lines are each electrically connected to a transistor. The transistor is electrically connected to the pixel electrode. The transistor has a gate electrode and The semiconductor device has an insulating layer on a gate electrode, a semiconductor layer on the insulating layer, and a pair of electrodes on the semiconductor layer. The semiconductor layer includes a first metal oxide layer and a second metal oxide layer on the first metal oxide layer. The first metal oxide layer has a region having lower crystallinity than the second metal oxide layer. The transistor has a first region connected to the pixel electrode. The first region has a function of transmitting visible light. Visible light is transmitted through the first region and the liquid crystal element. The light is then emitted to the outside of the display device.

[0010] The first metal oxide layer and the second metal oxide layer each independently contain indium and a metal M( M is aluminum, gallium, yttrium, or tin) and zinc; For example, the ratio of the number of atoms of indium, metal M, and zinc is In:M:Zn=4. For :x:y, x is between 1.5 and 2.5, and y is between 2 and 4. For example, For example, when the ratio of the numbers of atoms of indium, metal M, and zinc is In:M:Zn=5:x:y, x is 0.5 or more and 1.5 or less, and y is 5 or more and 7 or less.

[0011] The second metal oxide layer preferably has a crystal portion having c-axis orientation.

[0012] The display device having the above configuration may further include a touch sensor. It is located closer to the display surface than the crystal element and the transistor.

[0013] The scanning lines preferably have portions overlapping the semiconductor layer.

[0014] Visible light may be transmitted through the first region and then through the liquid crystal element, and then emitted to the outside of the display device. Alternatively, the visible light is transmitted through the liquid crystal element and the first region in this order, and is emitted to the outside of the display device. Good too.

[0015] The direction in which the scanning lines extend is preferably intersecting with the direction in which the signal lines extend. It is preferable that the direction in which the pixels are arranged crosses the direction in which the signal lines extend. .

[0016] One aspect of the present invention is a display device having any one of the above configurations, Flexible printed circuit (hereinafter referred to as FPC) or is equipped with a TCP (Tape Carrier Package) or other connector. Display module, or COG (Chip On Glass) or COF (C Display modules with ICs mounted using the "hip on film" method, etc. It is a rule.

[0017] One aspect of the present invention is a display device including the above-mentioned display module, an antenna, a battery, a housing, a camera, a speaker, and the like. The electronic device has at least one of a speaker, a microphone, and an operation button. Effect of the Invention

[0018] According to one embodiment of the present invention, a liquid crystal display device with a high aperture ratio can be provided. According to one embodiment of the present invention, a liquid crystal display device with low power consumption can be provided. According to one embodiment of the present invention, a high-definition liquid crystal display device can be provided. According to one embodiment, a highly reliable liquid crystal display device can be provided.

[0019] The description of these effects does not preclude the existence of other effects. However, it is not necessary to have all of these effects. However, it is possible to extract effects other than these. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view showing an example of a display device. [Diagram 2] FIG. 1 is a cross-sectional view showing an example of a display device. [Diagram 3] FIG. 1 is a cross-sectional view showing an example of a display device. [Figure 4] FIG. 2 is a top view illustrating an example of a subpixel. [Diagram 5] FIG. 2 is a top view illustrating an example of a subpixel. [Figure 6] FIG. 1 is a cross-sectional view showing an example of a display device. [Figure 7] FIG. 1 is a cross-sectional view showing an example of a display device. [Figure 8] FIG. 1 is a cross-sectional view showing an example of a display device. [Figure 9] 1A and 1B are diagrams showing examples of pixel arrangement and configuration; [Figure 10] FIG. 1 is a perspective view showing an example of a display device. [Figure 11] FIG. 1 is a perspective view showing an example of a display device. [Figure 12] FIG. 4 is a diagram showing an example of an operation mode. [Figure 13] 3A and 3B are a block diagram and a timing chart of a touch sensor. [Figure 14] 1A and 1B are a block diagram and a timing chart of a display device. [Figure 15] 4A to 4C are diagrams illustrating the operation of a display unit and a touch sensor. [Figure 16] 4A to 4C are diagrams illustrating the operation of a display unit and a touch sensor. [Figure 17] 1A and 1B are diagrams illustrating examples of electronic devices. [Figure 18] 1A and 1B are diagrams illustrating examples of electronic devices. [Figure 19] FIG. 2 is a cross-sectional view illustrating the display device of the first embodiment. [Figure 20] FIG. 4 is a graph showing the light transmittance of a stacked structure included in the display device of Example 1. [Figure 21] 4A to 4C illustrate a method for manufacturing a display device according to Example 2. [Figure 22] 4A to 4C illustrate a method for manufacturing a display device according to Example 2. [Diagram 23] FIG. 11 is a graph showing the light transmittance of a stacked structure included in the display device of Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The embodiment will be described in detail with reference to the drawings. However, the present invention is not limited to the following description. The present invention is not limited to the above embodiment, and various changes and modifications may be made in the form and details without departing from the spirit and scope of the present invention. It will be easily understood by those skilled in the art that the above-mentioned invention can be obtained by the following embodiments. It should not be construed as being limited to the contents described.

[0022] In the configuration of the invention described below, the same parts or parts having similar functions are referred to as the same parts. The same reference numerals are used in common among different drawings, and the repeated explanations are omitted. When referring to a function, the same hatch pattern may be used and no particular reference number may be given.

[0023] In addition, the position, size, range, etc. of each component shown in the drawings are not necessarily the same as in the actual embodiment, in order to facilitate understanding. Therefore, the disclosed invention may not necessarily represent the position, size, range, etc. Furthermore, the present invention is not limited to the position, size, range, etc. disclosed in the drawings.

[0024] The words "film" and "layer" may be interchangeable depending on the circumstances. For example, the term "conductive layer" can be replaced with "conductive film" Alternatively, for example, the term "insulating film" can be changed to " The term "insulating layer" may be changed to "insulating layer."

[0025] In this specification, the term "metal oxide" refers to a metal oxide in a broad sense. Metal oxides are oxide insulators and oxide conductors (including transparent oxide conductors). , oxide semiconductor (also called OS) For example, when a metal oxide is used for the semiconductor layer of a transistor, the metal An oxide may be called an oxide semiconductor. In other words, the transistor can be a transistor including a metal oxide or an oxide semiconductor.

[0026] In the present specification and the like, metal oxides having nitrogen are also referred to as metal oxides. Nitrogen-containing metal oxides are also called metal oxynitrides (met de). It may also be called tetrahydrofuran (tetrahydrofuran) oxynitride.

[0027] (Embodiment 1) In this embodiment, a display device according to one embodiment of the present invention will be described with reference to FIGS.

[0028] <1. Display device configuration example 1> First, the display device of the present embodiment will be described with reference to FIGS.

[0029] The display device of this embodiment mode includes a liquid crystal element and a transistor. The pixel electrode is electrically connected to the liquid crystal layer. The semiconductor layer of the transistor has a first metal oxide layer and a second metal oxide layer stacked together. The first metal oxide layer has a region that is less crystalline than the second metal oxide layer. The transistor has a first region connected to the pixel electrode. The region has a function of transmitting visible light. Visible light is transmitted through the first region and the liquid crystal element. , and is emitted to the outside of the display device.

[0030] Alternatively, the display device of this embodiment includes a liquid crystal element and a transistor. The pixel electrode, the liquid crystal layer, and the common electrode are electrically connected to the transistor. The transistor includes a gate electrode, an insulating layer on the gate electrode, and a semiconductor layer on the insulating layer. and a pair of electrodes on the semiconductor layer. The semiconductor layer includes a first metal oxide layer and a first gold and a second metal oxide layer on the first metal oxide layer. The first metal oxide layer is The transistor has a first region connected to the pixel electrode. The pixel electrode, the common electrode, and the first region have a function of transmitting visible light. The visible light passes through the first region and the liquid crystal element and is emitted to the outside of the display device.

[0031] In the display device of the present embodiment, the contact portion between the transistor and the pixel electrode transmits visible light. In order to achieve this, the contact portion can be provided in the display area. The higher the aperture ratio, the higher the light extraction efficiency. If the light output efficiency can be increased, the brightness of the backlight unit can be reduced. Therefore, the power consumption of the display device can be reduced. This can be achieved.

[0032] The display device of this embodiment further includes scanning lines and signal lines. The scanning lines and the signal lines are electrically connected to the transistors. By using a metal layer for the scanning lines and signal lines, the resistance value of the scanning lines and signal lines can be reduced. It is possible.

[0033] In addition, it is preferable that the scan line has a portion overlapping with a channel region of the transistor. Depending on the material used in the channel region of a transistor, it may become a transistor when irradiated with light. The characteristics of the transistor may vary. This prevents external light or backlight from irradiating the channel area. This can improve the reliability of the transistor. However, it has both the function of a scanning line and the function of a gate (or back gate). It's fine.

[0034] In one embodiment of the present invention, a transistor, a wiring, a capacitor, or the like is formed using a light-transmitting semiconductor Conductive and electrically conductive materials may be used.

[0035] The semiconductor film of the transistor can be formed using a light-transmitting semiconductor material. As the light-transmitting semiconductor material, a metal oxide or an oxide semiconductor (Oxid The oxide semiconductor is at least indium. It is preferable that the alloy contains indium (In). In particular, it is preferable that the alloy contains indium (In) and zinc (Zn). In addition to these, aluminum (Al), gallium (G), yttrium (Y) and the like are preferable. Lithium (Y), Tin (Sn), Copper, Vanadium, Beryllium, Boron, Silicon, Titanium , Iron, Nickel, Germanium, Zirconium, Molybdenum, Lanthanum, Cerium, Neo One selected from zinc, hafnium, tantalum, tungsten, or magnesium Or, multiple types may be included.

[0036] The conductive film of the transistor can be formed using a light-transmitting conductive material. The light-transmitting conductive material is one selected from the group consisting of indium, zinc, and tin, or It is preferable to include a plurality of types. Specifically, In oxide, In-Sn oxide (ITO:I Indium Tin Oxide), In-Zn oxide, In-W oxide, In -W-Zn oxide, In-Ti oxide, In-Sn-Ti oxide, In-Sn-Si oxide Examples of oxides include Zn oxide, Ga-Zn oxide, etc.

[0037] In addition, a conductive film of a transistor may be formed by adding an impurity element to the conductive film to reduce the resistance. The oxide semiconductor having a low resistance may be an oxide conductor (OC: It can be called a ferroelectric material.

[0038] For example, an oxide conductor is formed by forming oxygen vacancies in an oxide semiconductor and adding hydrogen to the oxygen vacancies. By this, a donor level is formed near the conduction band. As a result, the oxide semiconductor becomes highly conductive and becomes a conductor.

[0039] In addition, oxide semiconductors have a large energy gap (for example, an energy gap of 2 0.5 eV or more), it is transparent to visible light. The material conductor is an oxide semiconductor having a donor level near the conduction band. Conductors are less affected by absorption due to donor levels, and exhibit the same level of absorption as oxide semiconductors for visible light. It has a light transmittance of .

[0040] In addition, the oxide conductor may include at least one metal element contained in the semiconductor film of the transistor. It is preferable that the oxide semiconductors constituting the transistors each have the same metal element. By using this material for two or more layers, the manufacturing equipment (e.g., deposition equipment, processing equipment, etc.) can be reduced by two or more Since it can be commonly used in the above steps, the manufacturing cost can be reduced.

[0041] FIG 1 is a perspective view of a display device 100A. For clarity, FIG 1 does not show a polarizing plate 130 and other components. In FIG. 1, the substrate 61 is indicated by a dashed line. FIG. 3A is a cross-sectional view of the display device 100A. FIG. 2C is an enlarged view of a transistor 201 included in the display device 100A. FIG. 3B is an enlarged view of the transistor 206 included in the display device 100A. This is a variation of 206.

[0042] The display device 100A includes a display unit 62 and a drive circuit unit 64. FPC72 and IC73 are implemented.

[0043] The display unit 62 has a plurality of pixels and has a function of displaying an image.

[0044] A pixel has a plurality of sub-pixels. For example, a sub-pixel that exhibits red, a sub-pixel that exhibits green, and A single pixel is formed by a sub-pixel that exhibits blue and a sub-pixel that exhibits blue, so that the display unit 62 displays full color. The colors of the sub-pixels are not limited to red, green, and blue. A pixel may include sub-pixels of colors such as white, yellow, magenta, or cyan. In this specification and the like, a sub-pixel may be simply referred to as a pixel.

[0045] The display device 100A includes a scanning line driving circuit and / or a signal line driving circuit. Alternatively, both the scanning line driver circuit and the signal line driver circuit may not be provided. When the display device 100A has a sensor such as a touch sensor, the display device 100A In the present embodiment, the driving circuit section 64 includes a scanning line The display unit 62 includes a scanning line driver circuit that applies a scanning signal to the scanning lines of the display unit 62. It has the function of outputting.

[0046] In the display device 100A, the IC 73 is mounted on the substrate 51 by a mounting method such as the COG method. The IC 73 includes, for example, a signal line driving circuit, a scanning line driving circuit, and a sensor driving circuit. It has one or more of the following paths.

[0047] The display device 100A is electrically connected to an FPC 72. Signals and power are supplied from the outside to the C73 and the drive circuit section 64. A signal can be output from IC73 to the outside via this pin.

[0048] An IC may be mounted on the FPC 72. For example, the FPC 72 may include a signal line drive circuit. An IC having one or more of a scanning line driver circuit, a scanning line driver circuit, and a sensor driver circuit is mounted. It may be possible.

[0049] Signals and power are supplied to the display unit 62 and the drive circuit unit 64 through wiring 65. Signals and power are input to the wiring 65 from the IC 73 or from the outside via the FPC 72. do.

[0050] 2A and 3A are cross-sectional views including a display section 62, a driving circuit section 64, and wiring 65. In the cross-sectional views of the display device shown in FIG. 2A and subsequent figures, the display unit 62 is a single subpixel. The display area 68 and the non-display area 66 located around it are shown.

[0051] In FIG. 2A, the polarizing plate 130 is located on the substrate 61 side, and the backlight unit 131 is located on the substrate 51 side. In this example, a light 45 from the backlight unit is first incident on the substrate. The light is incident on the plate 51, and passes through the contact portion between the transistor 206 and the pixel electrode 111, the liquid crystal element 40, The light is transmitted through the colored layer 131, the substrate 61, and the polarizing plate 130 in that order and is taken out of the display device 100A. It is served.

[0052] In FIG. 3A, the polarizing plate 130 is located on the substrate 51 side, and the backlight unit 130 is located on the substrate 61 side. In this example, a light 45 from the backlight unit is first incident on the substrate. The light is incident on the plate 61 and passes through the colored layer 131, the liquid crystal element 40, the transistor 206 and the pixel electrode 111. The light is transmitted through the contact portion, the substrate 51, and the polarizing plate 130 in that order and is taken out of the display device 100A. It is served.

[0053] In this manner, the display device of the present embodiment can be realized without changing the structure between the substrate 51 and the substrate 61. Either the substrate 51 side or the substrate 61 side can be the display surface side. The decision on which to use will be made based on the layout of the backlight unit, polarizing plate, touch sensor, etc. It is possible.

[0054] In the following, the description will be given taking FIG. 2(A) as an example, but the same applies to FIG. 3(A).

[0055] The display device 100A is an example of a transmissive liquid crystal display device using a lateral electric field type liquid crystal element. .

[0056] As shown in FIG. 2A, the display device 100A includes a substrate 51, a transistor 201, a transistor A resistor 206, a liquid crystal element 40, an alignment film 133a, an alignment film 133b, a connection portion 204, and an adhesive layer. 141, colored layer 131, light-shielding layer 132, overcoat 121, substrate 61, and polarizing plate 1 30 etc.

[0057] The non-display area 66 is provided with a transistor 206. 2 shows an enlarged view of the rotor 206.

[0058] The transistor 206 includes a gate 221, an insulating layer 213, a conductive layer 222a, and a conductive layer 222c. , and a semiconductor layer 231.

[0059] The gate 221 overlaps with the semiconductor layer 231 via the insulating layer 213. The conductive layer 222a and the conductive layer 222c function as a second insulating layer. It is connected to 31.

[0060] In FIG. 2A, the pixel electrode 111 of the liquid crystal element 40 is connected to the conductive layer 222c via the conductive layer 222c. , and is electrically connected to the semiconductor layer 231.

[0061] The conductive layer 222c is formed using a material that transmits visible light. The contact portion between the transistor and the display area 68 can be provided. This makes it possible to increase the aperture ratio of the sub-pixel and reduce the power consumption of the display device. Cut.

[0062] As shown in FIG. 2C, the semiconductor layer 231 is made of a first metal oxide layer 231a and a first metal and a second metal oxide layer 231b on the metal oxide layer 231a.

[0063] The first metal oxide layer 231a and the second metal oxide layer 231b are made of In and M (M It is preferable that the metal oxide comprises Ga, Al, Y, or Sn) and Zn.

[0064] The first metal oxide layer 231a and the second metal oxide layer 231b each have an atomic ratio of In When the atomic ratio of M is larger than that of M, the field effect mobility of the transistor can be increased. As an example, the first metal oxide layer 231a and the second metal oxide layer 23 The ratio of the number of In, M, and Zn atoms in 1b is In:M:Zn=4:2:3, respectively. It is preferable that the ratio is In:M:Zn=5:1:7 or in the vicinity thereof. Here, the vicinity means that when In is 4, M is 1.5 or more and 2.5 or less, and Zn is 2 or more. When In is 5, M is 0.5 to 1.5 and Zn is 5 to 7. In this way, the first metal oxide layer 231a and the second metal oxide layer 231b are By making the composition roughly the same, the same sputtering target can be used for formation, so This reduces manufacturing costs.

[0065] The first metal oxide layer 231a and the second metal oxide layer 231b are made of metals having different compositions. Although a film formed using a target having the same composition may be used, it is particularly preferable to use a target having the same composition and a large It is preferable to use a laminated film that is deposited in succession without exposure to air. In addition, the first metal oxide layer 231a and the second metal oxide layer 23 This can prevent impurities from remaining between 1b.

[0066] The second metal oxide layer 231b is a region having a higher crystallinity than the first metal oxide layer 231a. It is preferable that the second metal oxide layer 231b contains the first metal oxide. Therefore, the conductive layer 2 can be a film having higher etching resistance than the conductive layer 231a. When processing the conductive layer 222a and the conductive layer 222c, the second metal oxide layer 231b is etched. Therefore, as shown in Fig. 2(A) and (B), It is possible to realize a transistor having a channel etch structure. The second metal oxide layer 231b located on the back channel side is made of a highly crystalline film. Therefore, impurities that may diffuse into the first metal oxide layer 231a on the gate 221 side can be reduced. This makes it possible to realize a highly reliable transistor.

[0067] In addition, the first metal oxide layer 231a has a lower crystallinity than the second metal oxide layer 231b. By using a film including the region, oxygen is easily diffused into the first metal oxide layer 231a. In this way, the rate of oxygen vacancies in the first metal oxide layer 231a can be reduced. The first metal oxide layer 231a is located on the side close to the gate 221, and is mainly used for forming a channel. Since this layer is easily damaged, the use of such a film makes it possible to realize highly reliable transistors. can.

[0068] The first metal oxide layer 231a and the second metal oxide layer 231b are formed, for example, under different film forming conditions. For example, the first metal oxide layer 231a and the second metal oxide layer 231b are The flow rate of oxygen gas in the deposition gas can be made different between the metal oxide layer 231a and the metal oxide layer 231b.

[0069] At this time, the deposition conditions for the first metal oxide layer 231a were as follows: total gas flow rate of oxygen gas: The ratio of the oxygen flow rate to the total oxygen (also called the oxygen flow rate ratio) is set to 0% or more and 30% or less, preferably 5% or more and 15% or less. By setting the oxygen flow rate ratio as described above, the crystallinity of the first metal oxide layer 231a can be improved. It can be lowered.

[0070] On the other hand, the second metal oxide layer 231b is formed under the following conditions: the oxygen flow rate is set to be greater than 30%; 100% or less, preferably 50% or more and 100% or less, and more preferably 70% or more and 100% or less. By setting the oxygen flow rate ratio as described above, the crystallinity of the second metal oxide layer 231b can be improved. It can be made higher.

[0071] The substrate temperature during the formation of the first metal oxide layer 231a and the second metal oxide layer 231b is The temperature is preferably from room temperature (25°C) to 200°C, and more preferably from room temperature to 130°C. By setting the substrate temperature within the above range, when a large-area glass substrate is used, the substrate is prevented from bending or cracking. Here, the first metal oxide layer 231a and the second metal oxide layer 231b can suppress the distortion. By setting the substrate temperature during film formation for the layer 231b and the layer 231c at the same temperature, productivity can be improved. In addition, for example, when the first metal oxide layer 231a and the second metal oxide layer 231b are formed, When the substrate temperatures are made different, the substrate temperature during the deposition of the second metal oxide layer 231b is set higher. This can further improve the crystallinity of the second metal oxide layer 231b.

[0072] For example, the first metal oxide layer 231a may be formed of a cloud-aligned ion-stimulated optical crystal (CAC-OS). A composite oxide semiconductor (composite oxide semiconductor) film is used, and a second metal CAAC-OS (c-axis-aligned crystal It is preferable to use a thin film of semiconductor line oxide.

[0073] The conductive layer used for the gate 221 may function as a scanning line. The conductive layer may have a function as a scanning line and a function as a gate 221. In addition, the conductive layer used for the conductive layer 222a may have a function as a signal line. Even if one conductive layer has a function as a signal line and a function as the conductive layer 222a, It is preferable that the resistance of the conductive layer functioning as the scanning line or the signal line is sufficiently low. Therefore, the conductive layer functioning as the scanning line or the signal line is formed using a metal, an alloy, etc. It is preferable that the conductive layer functioning as the scanning line or the signal line has a function of blocking visible light. Materials that can achieve this may also be used.

[0074] Specifically, conductive materials that transmit visible light are different from conductive materials that block visible light, such as copper and aluminum. Therefore, the resistivity of the bus lines such as the scanning lines and the signal lines may be higher than that of the conductive materials. In order to prevent signal delay, the OLED uses conductive materials (metallic materials) that have low resistivity and block visible light. However, depending on the size of the pixel, the width and thickness of the bus line, Depending on the thickness, a conductive material that transmits visible light may be used for the bus line.

[0075] By using a conductive layer that blocks visible light for the gate 221, the light from the backlight is reflected by the semiconductor layer 231. In this way, the semiconductor layer 231 can be used as a conductive layer that blocks visible light. By overlapping the two layers, it is possible to suppress the fluctuation in the transistor characteristics caused by light. Reliability can be improved.

[0076] A light-shielding layer 132 is provided on the substrate 61 side of the semiconductor layer 231, and a light-shielding layer 132 is provided on the substrate 51 side of the semiconductor layer 231. A gate 221 that blocks visible light is provided on the screen, so that external light and backlight light are blocked. The conductor layer 231 can be prevented from being irradiated with the light.

[0077] Here, FIG. 3B shows a modified example of the transistor 206. 2 shows an example in which a part of the semiconductor layer 231 of the transistor 206 is located in the display area 68. The semiconductor layer is made of silicon, typically amorphous silicon or low-temperature polysilicon. When using a semiconductor layer, the semiconductor layer absorbs part of the visible light, so the light is transmitted through the semiconductor layer. In addition, if impurities such as phosphorus or boron are present in silicon, the Therefore, the low resistance region formed in the silicon may be transparent. However, in one aspect of the present invention, Both oxide semiconductors (OS) and oxide conductors (OC) have transparency to visible light. Therefore, the aperture ratio of the pixel or sub-pixel can be improved.

[0078] The transistor 206 is covered with an insulating layer 212, an insulating layer 214, and an insulating layer 215. Note that the insulating layer 212 and the insulating layer 214 can be regarded as components of the transistor 206. The transistor can also suppress the diffusion of impurities into the semiconductor that constitutes the transistor. Preferably, the insulating layer 215 functions as a planarization layer. It can be done.

[0079] Each of the insulating layers 212 and 213 preferably has an excess oxygen region. The edge layer 212 and the insulating layer 213 have an excess oxygen region, so that the excess oxygen is not formed in the semiconductor layer 231. The oxygen vacancies that may be formed in the semiconductor layer 231 are compensated for by the excess oxygen. Since the filling can be performed, a highly reliable transistor can be provided.

[0080] The insulating layer 212 is a silicon oxide film or a silicon oxynitride film formed in an atmosphere containing oxygen. It is preferable to use an oxide insulating film such as a silicon oxide film or a silicon oxynitride film. As the insulating layer 214 on the silicon film, an insulating film that is difficult for oxygen to diffuse and penetrate, such as a silicon nitride film, is used. It is preferable to form an oxide insulating film in an atmosphere containing oxygen. This makes it possible to make an insulating film that can release more oxygen. By performing heat treatment on an insulating film and an insulating film that does not easily diffuse or penetrate oxygen, As a result, oxygen can be supplied to the semiconductor layer 231. The defects at the interface between the semiconductor layer 231 and the insulating layer 212 are repaired to reduce the defect level density. This makes it possible to realize a display device with extremely high reliability.

[0081] The display area 68 is provided with a liquid crystal element 40. The liquid crystal element 40 is a FFS (Frin This is a liquid crystal element to which the GE Field Switching (GE Field Switching) mode is applied.

[0082] The liquid crystal element 40 includes a pixel electrode 111, a common electrode 112, and a liquid crystal layer 113. The alignment of the liquid crystal layer 113 is controlled by the electric field generated between the electrode 111 and the common electrode 112. The liquid crystal layer 113 is located between an alignment film 133a and an alignment film 133b.

[0083] The common electrode 112 has a comb-like upper surface shape (also called a planar shape) or has slits. In FIG. 2(A) and FIG. 3(A), the display area of ​​one sub-pixel is In this example, one opening of the common electrode 112 is provided in the region 68. As the resolution of display devices increases, the number of subpixels per subpixel increases. Therefore, the number of openings provided in the common electrode 112 is limited to a plurality of openings. In other words, in a high-definition display device, the number of pixels (sub-pixels) can be reduced to one. Since the area of ​​the common electrode 112 is small, even if there is only one opening in the common electrode 112, the entire display area of ​​the sub-pixels is covered. A sufficient electric field can be generated across the body to orient the liquid crystals.

[0084] An insulating layer 220 is provided between the pixel electrode 111 and the common electrode 112. The pixel electrode 11 has a portion overlapping with the common electrode 112 via the insulating layer 220. In the region where the pixel electrode 111 and the colored layer 131 overlap, a common electrode 112 is disposed on the pixel electrode 111. It has some parts that are not included.

[0085] It is preferable to provide an alignment film in contact with the liquid crystal layer 113. The alignment film adjusts the alignment of the liquid crystal layer 113. In the display device 100A, the common electrode 112, the insulating layer 220, and the liquid crystal An alignment film 133a is disposed between the overcoat 121 and the liquid crystal layer 113. An alignment film 133b is located on the substrate 133a.

[0086] There are two types of liquid crystal materials: positive type, in which the anisotropy of the dielectric constant (Δε) is positive, and negative type, in which the anisotropy is negative. In one embodiment of the present invention, either material can be used, and the applied model The optimum liquid crystal material can be used depending on the mode and design.

[0087] In one embodiment of the present invention, it is preferable to use a negative type liquid crystal material. The influence of the quasielectric effect can be suppressed, and the transmittance according to the polarity of the voltage applied to the liquid crystal layer Therefore, the flicker is hardly noticeable to the user of the display device. The flexoelectric effect is mainly caused by the molecular shape, and can be suppressed by orientation distortion. This is a phenomenon in which polarization occurs. Negative liquid crystal materials have orientation distortions such as spreading and bending deformation. It's difficult.

[0088] In this embodiment, an element to which the FFS mode is applied is used as the liquid crystal element 40. It is possible to use liquid crystal elements with various modes. For example, VA (Ver (Twisted Nematic) mode, mode, IPS (In-Plane-Switching) mode, ASM (Axiall y Symmetric aligned Micro-cell) mode, OCB(O (Fptically Compensated Birefringence) mode, LC (Ferroelectric Liquid Crystal) mode, AFLC (AntiFerroelectric Liquid Crystal) mode, EC B(Electrically Controlled Birefringence) Uses liquid crystal elements that use mode, VA-IPS mode, guest host mode, etc. can be done.

[0089] In addition, the display device 100A is a normally black type liquid crystal display device, for example, a vertical alignment (VA A transmissive liquid crystal display device using a vertical alignment mode may be used. MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode, ASV (Advanced Super View) mode, etc. can be used.

[0090] A liquid crystal element is an element that controls the transmission or non-transmission of light by the optical modulation action of liquid crystal. The optical modulation of liquid crystals is achieved by applying an electric field (horizontal electric field, vertical electric field, or The liquid crystal used in the liquid crystal element is thermoplastic. ropic liquid crystal, low molecular liquid crystal, polymer liquid crystal, polymer dispersed liquid crystal (PDLC) Dispersed Liquid Crystal, Ferroelectric Liquid Crystal, Antiferroelectric Liquid Crystal These liquid crystal materials can exhibit a cholesteric phase, a smectic phase, etc., depending on the conditions. These phases include cubic phase, chiral nematic phase, isotropic phase, etc.

[0091] In addition, when the in-plane switching system is adopted, liquid crystal that exhibits a blue phase without using an alignment film may be used. The blue phase is one of the liquid crystal phases. When the temperature of a cholesteric liquid crystal is increased, the cholesteric The blue phase appears just before the transition from the crystalline phase to the isotropic phase. In order to improve the temperature range, a liquid crystal composition containing 5% by weight or more of chiral agent is used. The liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent is used for the liquid crystal layer 113. The response speed is short and the liquid crystal exhibits optical isotropy. The crystal composition does not require alignment treatment and has little viewing angle dependency. Since the rubbing process is unnecessary, electrostatic damage caused by the rubbing process is eliminated. This can prevent defects or damage to the liquid crystal display device during the manufacturing process. Cut.

[0092] Since the display device 100A is a transmissive liquid crystal display device, the pixel electrode 111 and the common electrode 1 A conductive material that transmits visible light is used for both the transistor 206 and the transistor 12. A conductive material that transmits visible light is used for one or more of the conductive layers. At least a part of the transistor 206 can be provided in the region 68. In (B), a semiconductor material that transmits visible light is used for the conductive layer 222c. explain.

[0093] Examples of conductive materials that transmit visible light include indium (In), zinc (Zn), and tin. It is preferable to use a material containing one or more selected from the group consisting of indium oxide, tin, and tin. Indium, indium tin oxide (ITO), indium zinc oxide, tungsten oxide Indium oxide, indium zinc oxide with tungsten oxide, indium zinc oxide with titanium oxide Indium oxide, indium tin oxide with titanium oxide, indium with silicon oxide Examples include tin oxide (ITSO), zinc oxide, and zinc oxide containing gallium. A graphene-containing film can also be used. The graphene-containing film can be, for example, graphene oxide. The film can be formed by reducing a film containing

[0094] The conductive layer 222c, the pixel electrode 111, and the common electrode 112 are each formed of an oxide. A conductive layer is preferably used. The oxide conductive layer is a semiconductor layer 231 of the transistor 206. For example, the conductive layer 222c preferably contains one or more of the metal elements contained in It is preferable that the material contains indium, and In, M (M is Al, Ti, Ga, Y, Zr, La, C More preferably, the oxide film contains Zn, Nd, Sn or Hf. Similarly, the pixel electrode 111 and the common electrode 112 each preferably contain indium. In, M (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf) It is more preferable that the oxide film contains Zn.

[0095] One or more of the conductive layer 222c, the pixel electrode 111, and the common electrode 112 are oxidized. The display device may be formed using an oxide semiconductor having the same metal element. By using it for two or more of the constituent layers, manufacturing equipment (e.g., film formation equipment, processing equipment, etc.) Since it is possible to use the same compound in two or more processes, the manufacturing cost can be reduced. do.

[0096] The oxide semiconductor has at least one of oxygen vacancies and impurity concentrations such as hydrogen and water in the film. On the other hand, oxide semiconductors are semiconductor materials whose resistance can be controlled. A process that increases at least one of oxygen deficiency and impurity concentration in a layer, or By selecting a treatment that reduces at least one of the concentrations of the oxide conductive layer, The resistivity can be controlled.

[0097] Note that the oxide conductive layer formed using the oxide semiconductor layer has a carrier density of A high-resistance and low-resistance oxide semiconductor layer, a conductive oxide semiconductor layer, or a highly conductive oxide semiconductor layer It can also be called a solid semiconductor layer.

[0098] In addition, by forming the oxide semiconductor layer and the oxide conductive layer using the same metal element, the manufacturing cost can be reduced. For example, by using a metal oxide target of the same metal composition, In addition, the manufacturing cost can be reduced by using a metal oxide target having the same metal composition. By using the above-mentioned gas, the etching gas or the etching However, the oxide semiconductor layer and the oxide conductive layer may be formed in the same manner. Even if the metal elements are included, the composition may be different. For example, In some cases, metal elements in the film may be released, resulting in a different metal composition.

[0099] For example, the insulating layer 212 is made of a silicon nitride film containing hydrogen, and the conductive layer 222c is made of an oxide semiconductor. When the insulating layer 212 is used, the conductivity of the oxide semiconductor is increased by hydrogen supplied from the insulating layer 212. For example, the insulating layer 220 may be a silicon nitride film containing hydrogen, and the pixel electrode 1 may be a silicon nitride film. When an oxide semiconductor is used for the insulating layer 220, the oxide semiconductor is heated by hydrogen supplied from the insulating layer 220. It can increase the body's electrical conductivity.

[0100] In the display device 100A, a colored layer 131 and a light-shielding layer 13 are provided on the substrate 61 side of the liquid crystal layer 113. The colored layer 131 is provided at least in a portion overlapping with the display region 68 of the sub-pixel. A light-shielding layer 132 is provided in the non-display area 66 of the pixel (sub-pixel). The light-shielding layer 132 overlaps at least a portion of the transistor 206.

[0101] An overcoat 121 is provided between the colored layer 131 and the light-shielding layer 132 and the liquid crystal layer 113. It is preferable to provide the overcoat 121 in the form of a colored layer 131, a light-shielding layer 132, etc. This can prevent impurities contained in the liquid crystal layer 113 from diffusing into the liquid crystal layer 113 .

[0102] The substrate 51 and the substrate 61 are bonded together by an adhesive layer 141. A liquid crystal layer 113 is sealed in the area surrounded by the adhesive layer 141 and the insulating layer 142 .

[0103] When the display device 100A is made to function as a transmissive liquid crystal display device, the polarizing plate is In FIG. 2A, the polarizing plate 130 on the substrate 61 side is shown. The light 45 from the backlight arranged on the outer side of the polarizing plate provided on the substrate 51 side is The light is incident through a polarizing plate. At this time, a voltage is applied between the pixel electrode 111 and the common electrode 112. By controlling the alignment of the liquid crystal layer 113, the optical modulation of light can be controlled. In addition, the intensity of the light emitted through the polarizing plate 130 can be controlled. Since the color layer 131 absorbs light outside a specific wavelength range, the emitted light is, for example, red. The resulting light will be colored blue or green.

[0104] In addition to the polarizing plate, for example, a circular polarizing plate can be used. For example, a linear polarizing plate and a quarter-wave retardation plate can be laminated. This makes it possible to reduce the viewing angle dependency of the display device.

[0105] The driver circuit portion 64 includes a transistor 201. An enlarged view is shown.

[0106] The transistor 201 includes a gate 221, an insulating layer 213, a semiconductor layer 231, a conductive layer 222a, and a One of the conductive layer 222a and the conductive layer 222b is a solenoid. The conductive layer 222a and the conductive layer 222b function as a source and a drain, respectively. , are electrically connected to the semiconductor layer 231, respectively.

[0107] As shown in FIG. 2B, the semiconductor layer 231 includes a first metal oxide layer 231a and a first metal and a second metal oxide layer 231b on the metal oxide layer 231a. For details, see the description of transistor 206.

[0108] The transistors provided in the driver circuit portion 64 do not need to have a function of transmitting visible light. Therefore, the conductive layer 222a and the conductive layer 222b are formed in the same process using the same material (preferably The insulating layer 11 can be formed by using a material having a low resistivity, such as a metal.

[0109] In the connection portion 204, the wiring 65 and the conductive layer 251 are connected to each other, and the conductive layer 251 and the connection body 24 2 are connected to each other. That is, in the connection portion 204, the wiring 65 is connected to the conductive layer 251. The connector 242 is electrically connected to the FPC 72. Signals and power can be supplied to the wiring 65 from the FPC 72 .

[0110] The wiring 65 is connected to the conductive layers 222a and 222b of the transistor 201 and the The conductive layer 222a of the conductive layer 206 can be formed using the same material and process. The layer 251 is formed of the same material and in the same process as the pixel electrode 111 of the liquid crystal element 40. In this way, the conductive layer constituting the connection section 204 can be formed on the display section 62 and the drive circuit section. If the conductive layer is made of the same material and in the same process as that used in 64, the number of processes can be prevented from increasing. This is preferable.

[0111] The transistors 201 and 206 may have the same structure or different structures. The transistors in the driver circuit section 64 and the transistors in the display section 62 are the same. The driving circuit section 64 may have a plurality of structures. The display unit 62 may have a transistor having a plurality of structures. For example, a shift register circuit, a buffer circuit, and a storage circuit included in the scanning line driver circuit may be A transistor having two gates electrically connected to one or more of the protection circuits. It is preferable to use a stencil.

[0112] [Sub-pixel configuration example] 4 is a top view of a subpixel to which one embodiment of the present invention is applied. FIG. 5 is a top view of a comparative subpixel. FIG.

[0113] Although some of the points may be repeated, first, the characteristics of a pixel (sub-pixel) in one embodiment of the present invention will be described. I will explain this in more detail.

[0114] A pixel is composed of a transistor, a capacitor, a scanning line, a signal line, etc. These components are They are often made of metal films with low resistivity. Metal films do not transmit light, so The portion formed using the film is excluded from the display area, and as a result, the aperture ratio of the pixel is small. In particular, as the resolution increases, the aperture ratio decreases significantly. As the amount of light decreases, more light is needed to achieve higher brightness and contrast. This leads to an increase in the power consumption of the backlight.

[0115] In view of the above, in one embodiment of the present invention, a transistor, a capacitor, a wiring, and a capacitor provided in a pixel are One or more of the contact parts are configured to transmit visible light. These components are formed using materials that transmit visible light, such as semiconductors and oxide conductors. Since the components in the pixels transmit visible light, the aperture ratio can be improved and the backlight can be used more efficiently. It is possible to reduce power consumption. Regarding the scanning lines, signal lines, power supply lines, and peripheral circuits, In order to reduce resistance, metal materials are used. In this way, materials are selected according to function, and conductive films are It is preferable to separately prepare the above.

[0116] By using materials that transmit visible light, such as oxide semiconductors and oxide conductors, Unlike silicon, oxide semiconductors can be doped with impurities. Even if the resistance is reduced by applying a pressure, the film has the characteristic of being transparent to visible light.

[0117] 4 and 5 show a sub-LCD device having a liquid crystal element of a vertical electric field mode such as a TN mode or a VA mode. 4 is a top view of a subpixel to which one embodiment of the present invention is applied. 1A and 1B are top views of a comparative subpixel.

[0118] 4A and 5A show a stacked structure from the gate 223 to the pixel electrode 111 of the subpixel. The structure is a top view seen from the pixel electrode 111 side. The display area 68 of FIG. 4(A) is indicated by a thick dotted frame. 5(B) or a top view of the laminated structure of FIG. 5(A) from which the pixel electrode 111 is removed.

[0119] The transistors shown in FIGS. 4 and 5 have gates above and below the channel.

[0120] The gate 221 and the gate 223 are electrically connected. Electrically connected transistors have a higher field effect transition than other transistors. This makes it possible to increase the mobility and on-current. Furthermore, the area occupied by the circuit portion can be reduced. By using a transistor with a large on-state current, it is possible to increase the size of a display device or Even if the number of wiring increases with increasing resolution, it is possible to reduce signal delays in each wiring. This makes it possible to suppress display unevenness. As a result, a highly reliable transistor can be realized.

[0121] In FIG. 4 and FIG. 5, one conductive layer functions as the scan line 228 and the gate 223. It can be said that the gate 221 and the gate 223 have the same function as the gate 222. It is preferable that the conductive layer also functions as a scan line. The resistance of the layer is preferably sufficiently low so that the conductive layer that functions as the scan line 228 is It is preferable that the conductive layer functioning as the scan line 228 is formed using a metal, an alloy, etc. A material having a function of blocking visible light may be used for the light-shielding layer.

[0122] In FIG. 4 and FIG. 5, one conductive layer functions as the signal line 229 and the conductive layer 222a. The resistance of the conductive layer functioning as the signal line 229 is sufficiently low. Therefore, it is preferable that the conductive layer functioning as the signal line 229 is made of a metal, an alloy, or the like. The conductive layer functioning as the signal line 229 is preferably formed of a material having a function of blocking visible light. Materials having such properties may also be used.

[0123] The gates 221 and 223 are each provided with a single layer of either a metal material or an oxide conductor. For example, the gate 221 and the gate 223 may be stacked together. An oxide conductor may be used for one and a metal material may be used for the other.

[0124] The transistor uses an oxide semiconductor layer as a semiconductor layer, and has a gate 221 and a gate 223. At least one of the insulating layers may be an oxide conductive layer. The oxide semiconductor layer and the oxide conductive layer are preferably formed using an oxide semiconductor.

[0125] 4 and 5 show an example in which a capacitance line 244 is provided in the subpixel. , formed of the same material and in the same process as the conductive layer (e.g., gate 221) of the transistor. In FIG. 4, the capacitor line 244 is overlapped with the conductive layer 245, and the conductive layer 245 is electrically connected to the conductive layer 245. In FIG. 5, a conductive layer 222c is provided. In FIG. 4, the conductive layer 222c is connected to the pixel electrode 111. In FIG. 5, the conductive layer 222b is connected to the pixel electrode 111.

[0126] In the structure shown in FIG. 4, at least a part of the capacitor element, the conductive layer 222c, and the pixel electrode 111 are The contact portion can be provided in the display area 68. Therefore, compared to the configuration shown in FIG. Therefore, the configuration shown in FIG. 4 can increase the aperture ratio of the sub-pixel. The force can be reduced.

[0127] In one embodiment of the present invention, a contact portion between the pixel electrode 111 and the transistor and a capacitor By providing the element in the display region 68, the aperture ratio can be increased by 10% or more, and even 20% or more. This can reduce the power consumption of the backlight by 10% or more, or even 20% or more. It can be reduced.

[0128] How much does the aperture ratio and backlight power consumption change when the configuration of Figure 5 is changed to the configuration of Figure 4? The estimate of how much the system will cost is as follows:

[0129] Here, assuming a large TV display, the sub-pixel layouts in Figs. 4 and 5 are as follows: A TN model with a resolution of 136ppi, a diagonal dimension of the display area of ​​65 inches, and a resolution of 8K. The case where the present invention is applied to a liquid crystal display device of this type will be described.

[0130] The size of the sub-pixel is 62.5 μm × 187.5 μm. The liquid crystal element is in a vertical electric field mode. The storage capacitor is formed between the gate wiring and the source wiring or the drain wiring. In addition, since it is assumed that the display will operate at 120Hz, two signal lines are arranged for each sub-pixel. The transistor has a BGTC type channel etch structure.

[0131] The aperture ratio of the pixel layout in FIG. 5(A) is 37.3%. The aperture ratio of the pixel electrode is 47.1%. By making the part transparent to visible light, the aperture ratio can be increased by 1.26 times. It is expected that the power consumption of the Cryto will be reduced by approximately 21%.

[0132] [About materials] Next, details of materials that can be used for each component of the display device of this embodiment will be described. In addition, the description of components that have already been described may be omitted. The following materials are also used for the display device and touch panel described below, as well as their components. It can be used as appropriate.

[0133] <Substrates 51 and 61> There is no particular limitation on the material of the substrate of the display device of one embodiment of the present invention, and various substrates can be used. For example, a glass substrate, a quartz substrate, a sapphire substrate, a semiconductor substrate, a ceramic substrate, A composite substrate, a metal substrate, a plastic substrate, or the like can be used.

[0134] By using a thin substrate, the display device can be made lighter and thinner. In addition, by using a substrate with a thickness that allows flexibility, a flexible display device can be realized. Cut.

[0135] In the display device of one embodiment of the present invention, a transistor or the like is formed over a formation substrate, and then a By using a fabrication substrate, the characteristics of Formation of good transistors, formation of transistors with low power consumption, and durable display devices To manufacture, impart heat resistance to a display device, and to reduce the weight or thickness of the display device. The substrate on which the transistor is transferred is a substrate on which a transistor can be formed. Not limited to substrates, paper substrates, cellophane substrates, stone substrates, wood substrates, cloth substrates (natural fibers (silk , cotton, linen), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (a acetate, cupra, rayon, recycled polyester, etc.), leather substrate, or rubber A substrate such as a rubber substrate can be used.

[0136] <Transistors 201, 206> The transistor included in the display device of one embodiment of the present invention is a top-gate or bottom-gate transistor. Alternatively, gate electrodes are provided above and below the channel. The semiconductor material used for the transistor is not particularly limited, and examples thereof include an oxide semiconductor, a silicon semiconductor, and the like. Examples of such materials include silicon and germanium.

[0137] The crystallinity of the semiconductor material used in the transistor is not particularly limited. A semiconductor having crystallinity (microcrystalline semiconductor, polycrystalline semiconductor, single crystal semiconductor, or semiconductor with partially crystalline regions) If a semiconductor having crystallinity is used, the This is preferable because it is possible to suppress deterioration of the resistor characteristics.

[0138] For example, Group 14 elements, compound semiconductors, or oxide semiconductors can be used for the semiconductor layer. Typically, a semiconductor containing silicon, a semiconductor containing gallium arsenide, or an indium An oxide semiconductor containing the above-mentioned compound can be used for the semiconductor layer.

[0139] An oxide semiconductor is preferably used as a semiconductor in which a channel of a transistor is formed. In particular, it is preferable to use an oxide semiconductor having a band gap larger than that of silicon. If a semiconductor material with a wider band gap and lower carrier density than silicon is used, This is preferable because the current in an off state of the transistor (off-state current) can be reduced.

[0140] For the oxide semiconductor, the above description and Embodiment 4 can be referred to.

[0141] By using an oxide semiconductor, fluctuations in electrical characteristics can be suppressed, resulting in highly reliable transistors. It can be achieved.

[0142] In addition, due to its low off-state current, the charge stored in the capacitance can be released through the transistor for a long period of time. By applying such transistors to pixels, It is also possible to stop the driving circuit while maintaining the gradation of the image displayed. A display device with reduced power consumption can be realized.

[0143] The transistors 201 and 206 are made of a highly purified oxide semiconductor layer in which the formation of oxygen vacancies is suppressed. This can reduce the off-state current of the transistor. This allows the retention time of electrical signals such as image signals to be extended, and writing is possible while the power is on. The write interval can also be set longer, which reduces the frequency of refresh operations. This has the effect of reducing power consumption.

[0144] In addition, the transistors 201 and 206 have a relatively high field effect mobility, and therefore can operate at high speed. By using such a transistor capable of high-speed driving in a display device, In addition, the transistors in the display section and the transistors in the driver circuit section can be formed on the same substrate. That is, a semiconductor device formed of a silicon wafer or the like can be used as a driving circuit. Since it is not necessary to use a display device, the number of parts of the display device can be reduced. By using transistors that can be driven at high speed, it is possible to provide high-quality images. can be done.

[0145] <Insulating layer> Insulating material that can be used for various insulating layers, overcoats, spacers, etc. in display devices As the insulating material, an organic insulating material or an inorganic insulating material can be used. For example, acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyamide Examples include diimide resins, siloxane resins, benzocyclobutene resins, and phenol resins. The inorganic insulating layer may be a silicon oxide film, a silicon oxynitride film, or a silicon nitride oxide film. silicon nitride film, aluminum oxide film, hafnium oxide film, yttrium oxide film, Zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film Examples of the thin film include a tungsten film, a cerium oxide film, and a neodymium oxide film.

[0146] Conductive layer In addition to the gate, source, and drain of a transistor, various wirings and electrodes of a display device The conductive layer is made of aluminum, titanium, chromium, nickel, copper, yttrium, and zirconium. Metals such as aluminum, molybdenum, silver, tantalum, or tungsten, or those mainly composed of these The alloy may be used as a single layer or a multilayer structure. A two-layer structure in which a titanium film is laminated on a tungsten film, a two-layer structure in which a titanium film is laminated on a tungsten film, A two-layer structure with a copper film laminated on a molybdenum film, and an alloy film containing molybdenum and tungsten A two-layer structure with a copper film laminated on top of a copper-magnesium-aluminum alloy film. A layer structure, a titanium film or a titanium nitride film, and an alumina layer on the titanium film or the titanium nitride film. An aluminum film or a copper film is laminated, and then a titanium film or a titanium nitride film is formed on the aluminum film or a copper film. A three-layer structure consisting of a molybdenum film or molybdenum nitride film and a molybdenum film or molybdenum nitride film. An aluminum or copper film is layered on top of the molybdenum film, and then a molybdenum film or For example, when the conductive layer has a three-layer structure, In this case, the first and third layers are titanium, titanium nitride, molybdenum, tungsten, molybdenum, alloys containing tungsten and tungsten, alloys containing molybdenum and zirconium, or molybdenum nitride The first layer is made of copper, aluminum, gold or silver, or copper and manganese. It is preferable to form a film made of a low resistance material such as an alloy of tungsten. Indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, titanium oxide Indium oxide containing tungsten, indium tin oxide containing titanium oxide, indium zinc oxide Alternatively, a conductive material having light transmitting properties, such as an oxide or ITSO, may be used.

[0147] Note that the oxide conductive layer may be formed by controlling the resistivity of the oxide semiconductor.

[0148] ≪Adhesive layer 141≫ The adhesive layer 141 may be made of a thermosetting resin, a photocurable resin, or a two-liquid mixed curable resin. Curable resins can be used, such as acrylic resins, urethane resins, and epoxy resins. , or siloxane resin, etc. can be used.

[0149] <Connector 242> The connector 242 may be, for example, an anisotropic conductive film (ACF). Conductive Film), or Anisotropic Conductive Paste (ACP) For example, a tropic conductive paste can be used.

[0150] ≪Colored layer 131≫ The colored layer 131 is a colored layer that transmits light in a specific wavelength range. Possible materials include metal materials, resin materials, and resin materials containing pigments or dyes. Examples include:

[0151] ≪Light blocking layer 132≫ The light-shielding layer 132 is provided, for example, between adjacent colored layers 131 of different colors. For example, A black matrix formed using a metal material or a resin material containing a pigment or dye. The light-shielding layer 132 may be made of a material other than the driving circuit section 64. It is preferable to provide the above-mentioned in an area other than the display unit 62, since this can suppress light leakage due to guided light, etc. I wish.

[0152] The thin films (insulating film, semiconductor film, conductive film, etc.) that make up the display device are each formed by sputtering. Chemical Vapor Deposition (CVD) method , vacuum evaporation, pulsed laser deposition (PLD) tion) method, Atomic Layer Deposition (ALD) method ) method, etc. As an example of the CVD method, plasma chemical vapor deposition (P Examples of thermal CVD include metal organic chemical vapor deposition (EMCVD) and thermal CVD. deposition (MOCVD: Metal Organic CVD) method.

[0153] The thin films (insulating films, semiconductor films, conductive films, etc.) that make up the display device are formed by spin coating, Dip, spray application, inkjet printing, dispensing, screen printing, offset Printing, doctor knife, slit coat, roll coat, curtain coat, knife coat The film can be formed by a method such as a coating method.

[0154] The thin films constituting the display device can be processed using a photolithography method or the like. Alternatively, an island-shaped thin film may be formed by a film formation method using a shielding mask. Even if the thin film is processed by imprinting, sandblasting, or lift-off, The photolithography method involves forming a resist mask on the thin film to be processed, The thin film is processed by etching or the like, and the resist mask is removed. a method of forming a thin film by exposure and development, and then processing the thin film into a desired shape; There is.

[0155] In the photolithography method, the light used for exposure is, for example, i-line (wavelength 365 nm) ), g-line (wavelength 436 nm), h-line (wavelength 405 nm), and a mixture of these. In addition, ultraviolet light, KrF laser light, ArF laser light, etc. can also be used. Exposure may also be performed by immersion lithography. Ultraviolet light (EUV: Extreme Ultraviolet) and X-rays In addition, electron beams can be used instead of light for exposure. Extreme ultraviolet light, X-rays Alternatively, the use of an electron beam is preferable because it enables extremely fine processing. When the exposure is performed by scanning a beam such as a photodiode, a photomask is not required. do.

[0156] For etching thin films, there are dry etching, wet etching, and sandblasting methods. etc. can be used.

[0157] <2. Display device configuration example 2> 6 to 8 show examples of the display device. FIG. 6 is a cross-sectional view of the display device 100B. FIG. 7 is a cross-sectional view of the display device 100C. FIG. 8(A) is a cross-sectional view of the display device 100D. 1 is a perspective view of the display device 100B, the display device 100C, and the display device 100D. 1A. Since this is the same as the display device 100A shown in FIG. 1, the description thereof will be omitted here.

[0158] The display device 100B shown in FIG. 6 has a transistor structure different from that of the display device 100A shown above. different.

[0159] Specifically, in the display device 100A, an example in which a transistor has one gate has been shown. In the display device 100B, the transistor 201 and the transistor 206 have two gates. As mentioned above, it is preferable that the two gates are electrically connected. , the field effect mobility of the transistor can be increased.

[0160] The rest of the configuration is similar to that of the display device 100A, so a detailed description will be omitted.

[0161] The display device 100C shown in FIG. 7 is a transmissive liquid crystal display device using a vertical electric field type liquid crystal element. Here is one example.

[0162] As shown in FIG. 7, the display device 100C includes a substrate 51, a transistor 201, a transistor 206, liquid crystal element 40, capacitance element 219, alignment film 133a, alignment film 133b, connection portion 20 4, adhesive layer 141, colored layer 131, light-shielding layer 132, overcoat 121, substrate 61, and and a polarizing plate 130.

[0163] The display portion 62 includes a transistor 206 , a liquid crystal element 40 , and a capacitor 219 .

[0164] The transistor 206 includes a gate 221, an insulating layer 213, a conductive layer 222a, and a conductive layer 222c. , and a semiconductor layer 231.

[0165] The conductive layer 222a and the conductive layer 222c are each connected to the semiconductor layer 231.

[0166] The liquid crystal element 40 is a liquid crystal element to which the VA mode is applied. The liquid crystal layer 113 has a pixel electrode 111, a common electrode 112, and a liquid crystal layer 113. It is located between the common electrodes 112 .

[0167] The pixel electrode 111 is connected to the semiconductor layer 23 of the transistor 206 through the conductive layer 222c. 1 is electrically connected to

[0168] The capacitor 219 includes a conductive layer 217 and a conductive layer 218. 8 overlaps with an insulating layer 213 interposed therebetween.

[0169] Here, the semiconductor layer 231, the conductive layer 222c, the conductive layer 217, and the conductive layer 218 have a visible A conductive material that transmits light is used. The conductive layer 218 and the conductive layer 222c are formed in the same process and in the same manner. This allows the pixel electrode 111 and the transistor 206 to be formed of the same material. The contact portion and the capacitive element 219 can be disposed in the display area 68. , the aperture ratio can be increased.

[0170] If the overcoat 121 has a planarizing function, the common electrode 112 can be formed flat. This makes it possible to suppress variations in the thickness of the liquid crystal layer 113.

[0171] An example of a material and a method for forming each layer of the transistor 206 shown in FIG. 7 will be described. .

[0172] First, a conductive film that transmits visible light is used as one electrode (conductive layer 217) of the capacitor. Then, a metal film such as a Cu film is formed as a gate 221 by sputtering. The metal film also functions as a scanning line. In the same process, gate wiring for transistors in the peripheral circuits can also be formed.

[0173] Next, a silicon nitride film and a silicon oxynitride film are formed as an insulating layer 213, which is a gate insulating layer. Next, a semiconductor layer 231 is formed by laminating CAC The CAC-OS film is then laminated with a CAAC-OS film. By forming a CAAC-OS film with high plasma resistance, Next, the conductive layer 231, which is a source electrode or a drain electrode, is As the conductive layer 222c, an indium zinc oxide film is formed by sputtering. The semiconductor layer 231 and the conductive layer 222c are each formed by wet etching. In order to prevent the semiconductor layer 231 from being etched when the conductive layer 222c is formed, In order to increase the selection ratio, a material different from that used for forming the semiconductor layer 231 is used in the etching solution. It is preferable to use the indium zinc oxide film in the same process. The other electrode of the element (conductive layer 218) can also be formed.

[0174] Next, a metal film such as a Cu film is formed as the signal line and the conductive layer 222a by sputtering. In addition, the metal film is used to form a transistor in a peripheral circuit in the same process. Source and drain wiring may also be formed.

[0175] Next, the insulating layer 212 and the insulating layer 214, which are passivation films, are deposited by a PECVD apparatus. A silicon oxynitride film and a silicon nitride film are laminated using a silicon nitride film. As the functional insulating layer 215, acrylic resin is applied and an opening (contact opening) is formed. Then, an ITO film is formed as the pixel electrode 111.

[0176] The gate electrode of the transistor in the pixel is made of a gold film such as a Cu film formed as a scan line. It is preferable to use a metal film. This allows the light from the backlight to reach the channel formation region. In FIG. 7, the transistor 206 and the pixel electrode 111 are The contact portion and the capacitance element 219 are configured to be transparent to visible light.

[0177] The display device 100D shown in FIG. 8A is the same as the display device 100C shown above, except that the pixel electrode 111 The arrangement and shape of the common electrode 112 are different from those of the first embodiment.

[0178] Both the pixel electrode 111 and the common electrode 112 have a comb-like top surface shape (also called a planar shape). Alternatively, the upper surface may have a slit.

[0179] In the display device 100D shown in FIG. 8A, the pixel electrode 111 and the common electrode 112 are disposed on the same plane. is provided on the surface.

[0180] Or, when viewed from above, the end of the slit of one electrode and the end of the slit of the other electrode The cross-sectional view of this case is shown in Figure 8(B).

[0181] Alternatively, when viewed from above, the pixel electrode 111 and the common electrode 112 have a portion where they overlap each other. A cross-sectional view of this case is shown in FIG.

[0182] Alternatively, the display unit 62 may be provided with both the pixel electrode 111 and the common electrode 112 when viewed from above. The cross-sectional view of this case is shown in Figure 8(D).

[0183] As described above, the display device of one embodiment of the present invention includes transistors and liquid crystal elements having various shapes. can be applied.

[0184] <3. Example of pixel arrangement> 9(A) and (B) show examples of pixel arrangement. In FIG. 9(A) and (B), An example is shown in which one pixel is composed of a green subpixel G and a blue subpixel B. In A) and B), a plurality of scanning lines 81 extend in the x direction, and a plurality of signal lines 82 extend in the y direction. The scanning lines 81 and the signal lines 82 extend in the same direction.

[0185] As shown in the double-dashed line frame in FIG. 9A, the subpixel includes a transistor 206, a capacitor element 3 4, and a liquid crystal element 40. The gate of the transistor 206 is electrically connected to the scan line 81. One of the source and drain of the transistor 206 is connected to the signal line 82. The other end is electrically connected to one electrode of the capacitance element 34 and one electrode of the liquid crystal element 40. The other electrode of the capacitance element 34 and the other electrode of the liquid crystal element 40 are electrically connected to each other. A constant potential is applied to each.

[0186] 9A and 9B show an example of applying source line inversion driving. Signals B1 and B2 are signals of the same polarity. Signal A1 and Signal B2 are signals of the same polarity. Signal A2 and signal B2 are signals with opposite polarities. It is.

[0187] As the resolution of a display device increases, the distance between sub-pixels becomes narrower. As shown in the dashed line frame, in the sub-pixel to which the signal A1 is input, In the vicinity of the signal line 82, the liquid crystal is easily affected by the potentials of both the signal A1 and the signal B1. This makes the liquid crystal alignment more likely to be poor.

[0188] In FIG. 9A, the direction in which a plurality of sub-pixels exhibiting the same color are arranged is the y direction. As shown in the dashed line frame in FIG. A subpixel having a different color is adjacent to the long side of the subpixel.

[0189] In FIG. 9B, the direction in which a plurality of sub-pixels exhibiting the same color are arranged is the x direction. As shown in the dashed line frame in FIG. 9B, the subpixel On the short side of each pixel, sub-pixels exhibiting the same color are adjacent to each other.

[0190] As shown in FIG. 9B, in the subpixel, a side that is approximately parallel to the direction in which the signal line 82 extends is In the case of the short side, the alignment of the liquid crystal is more likely to be poor than in the case of the long side (FIG. 9(A)). As shown in FIG. 9B, the area where the alignment defect of the liquid crystal is likely to occur can be narrowed. When the area is located between sub-pixels that exhibit the same color, and when it is located between sub-pixels that exhibit different colors, Compared to FIG. 9(A), display defects are less likely to be visually recognized by the user of the display device. In one embodiment, the direction in which the sub-pixels exhibiting the same color are arranged is the direction in which the signal line 82 extends. It is preferable that the direction of the wire be perpendicular to the longitudinal direction.

[0191] <4. Display device configuration example 3> One embodiment of the present invention is a display device (an input / output device or a touch panel) equipped with a touch sensor. The configuration of each of the above-mentioned display devices can be applied to a touch panel. In the present embodiment, the display device 100A is mainly provided with a touch sensor. will explain.

[0192] There is no limitation on a detection element (also referred to as a sensor element) included in a touch panel of one embodiment of the present invention. We offer a variety of sensors that can detect the proximity or contact of a finger, stylus, or other object. , can be applied as a sensing element.

[0193] The sensor type may be, for example, a capacitance type, a resistive film type, a surface acoustic wave type, or an infrared type. Various methods can be used, such as a pressure-sensitive method, an optical method, or a pressure-sensitive method.

[0194] In this embodiment, a touch panel having a capacitance type sensing element will be described as an example. .

[0195] The capacitive touch sensor includes a surface capacitive touch sensor and a projected capacitive touch sensor. The electrostatic capacitance type includes the self-capacitance type and the mutual capacitance type. This is preferable because it enables simultaneous multi-point detection.

[0196] The touch panel according to one embodiment of the present invention is formed by bonding a display device and a sensing element that are separately manufactured. A structure in which a substrate supporting a display element and / or an opposing substrate are provided with electrodes constituting a sensing element. Various configurations can be applied, such as a configuration in which a pole or the like is provided.

[0197] An example of a touch panel is shown in FIG. 10. FIG. 10(A) is a perspective view of a touch panel 350A. FIG. 10(B) is a perspective schematic view of FIG. 10(A). In FIG. 10B, the substrate 61 and the substrate 162 are shown. Only the outline is indicated by a dashed line.

[0198] The touch panel 350A is constructed by bonding a display device and a sensing element that are separately manufactured. be.

[0199] The touch panel 350A has an input device 375 and a display device 370, which are overlapped. It is provided.

[0200] The input device 375 includes a substrate 162, an electrode 127, an electrode 128, a plurality of wirings 137, and a plurality of The FPC 72b has the plurality of wirings 137 and the plurality of wirings 138. The FPC 72b is electrically connected to the IC 73b.

[0201] The display device 370 has a substrate 51 and a substrate 61 disposed opposite each other. The substrate 51 includes a display section 62 and a driving circuit section 64. Wiring 65 and the like are provided on the substrate 51. The FPC 72a is electrically connected to the wiring 65. The FPC 72a includes an IC 73a. It is provided.

[0202] Signals and power are supplied to the display unit 62 and the drive circuit unit 64 through wiring 65. The signal and power are input to the wiring 65 from the outside or IC 73a via the FPC 72a. .

[0203] The display device 100A shown in FIG. 2(A) can be applied to the display device 370 shown in FIG. can.

[0204] <5. Display device configuration example 4> An example of a touch panel is shown in Fig. 11. Fig. 11(A) is a perspective view of a touch panel 350B. FIG. 11(B) is a perspective schematic view of FIG. 11(A). In FIG. 11B, only the outline of the substrate 61 is shown by a dashed line. It is clearly stated.

[0205] The touch panel 350B has a function of displaying an image and a function as a touch sensor. It is an in-cell type touch panel.

[0206] The touch panel 350B has a configuration in which electrodes constituting sensing elements are provided only on the opposing substrate. This structure is advantageous compared to a structure in which a display device and a detector element are fabricated separately and then bonded together. In all cases, the touch panel can be made thinner or lighter, or the The number of parts can be reduced.

[0207] 11(A) and (B), the input device 376 is provided on the substrate 61. The wiring 137 and the wiring 138 of the input device 376 are connected to an FPC 7 provided on the display device 379. For example, in the connection portion 63, one of the wirings 137 (or the wiring 138) is electrically connected to the The conductive layer provided on the substrate 51 side is electrically connected to the conductive layer via a connector.

[0208] With this configuration, the FPC connected to the touch panel 350B is located on one board side ( In this case, it can be arranged only on the substrate 51 side. The FPC may be attached to the upper part of the board, but as shown in Figures 11(A) and (B), The switch panel 350B is provided with one FPC 72, and the FPC 72 is connected to a display device 379 and an input device. It is preferable to provide a signal to both the device 376 because this can simplify the configuration. Compared to connecting FPCs to both the board 51 and the board 61, This makes it easier to manufacture and reduces the number of parts.

[0209] The IC 73 may have a function to drive the input device 376. An IC for driving the input device 376 may be provided on the FPC 72. It may be mounted on a substrate 51 .

[0210] The conductive layer of the input device that overlaps the display area 68 is made of a material that transmits visible light. The conductive layer of the input device may be disposed only in the non-display area 66. By configuring the conductive layer of the input device so as not to overlap the display area 68, The visible light transmittance of the conductive layer material is not limited. For example, metals with low thermal conductivity can be used as wiring and electrodes for touch sensors. It is preferable to use a mesh wire. This reduces the resistance of the wiring and electrodes of the touch sensor. This is also suitable for use as a touch sensor for a large display device. Generally, metals are highly reflective materials, but they can be made darker by oxidation treatment, etc. Therefore, even when viewed from the display surface side, the image is not visible due to the reflection of external light. This can prevent a decline in sexual function.

[0211] The wiring and the electrodes are made of a metal layer and a layer with low reflectivity (also called a "dark layer"). The dark layer may be formed by laminating layers. An example of the dark layer is a layer containing copper oxide, copper chloride or tertiary chloride. The dark layer is made of Ag particles, Ag fibers, Cu particles, and other metals. Nanocarbon particles such as fine particles, carbon nanotubes (CNTs), graphene, etc., as well as PE It may be formed by using a conductive polymer such as DOT, polyaniline, or polypyrrole.

[0212] In the display device of this embodiment, since the transistor has a region through which visible light passes, The aperture ratio can be increased, which reduces the power consumption of the display device. do.

[0213] This embodiment mode can be appropriately combined with other embodiment modes. In the case where a plurality of configuration examples are shown in one embodiment, the configuration examples may be appropriately combined. It is possible to do this.

[0214] (Embodiment 2) In this embodiment, operation modes that can be performed in a display device according to one embodiment of the present invention will be described. This will be explained using 12.

[0215] In the following, we will assume that the device operates at a normal frame frequency (typically 60 Hz or higher and 240 Hz or lower). There are two operating modes: Normal mode, which operates at a slower frame rate, and Low mode, which operates at a slower frame rate. The idle stop (IDS) driving mode will be explained as an example.

[0216] In the IDS drive mode, the image data is written and then the image data is written. This is a driving method that stops switching of the image data. By extending the interval between writing the image data, the time required to write the image data during that time is reduced. The IDS drive mode can reduce the power consumption by the amount of power consumed by the IDS. The frame frequency can be set to about 1 / 100 to 1 / 10 of the normal frame rate. The video signal is the same between frames. Therefore, the IDS driving mode can display still images. This is particularly effective when displaying images using IDS driving, which reduces power consumption. This reduces noise and screen flicker, helping to reduce eye strain.

[0217] 12(A) to 12(C) show a pixel circuit and a normal driving mode and an IDS driving mode. 12A is a timing chart for explaining the operation of the first display element 501 ( Here, a reflective liquid crystal element) and a pixel circuit 5 electrically connected to a first display element 501. 12A, the pixel circuit 506 includes a signal line SL and A gate line GL, a transistor M1 connected to the signal line SL and the gate line GL, Capacitor Cs connected to resistor M1 LC This shows that:

[0218] The transistor M1 can be a leakage path for the data D1. The off-state current is preferably as small as possible. It is preferable to use a transistor having a metal oxide in the semiconductor layer. In the case where the metal oxide has at least one of a rectifying function and a switching function, Metal oxide semiconductor or oxide It can be called oxide semiconductor, or OS for short. As a typical example of a transistor, The following description will be given using a transistor (also referred to as an OS transistor) that is used in the present invention. A transistor that uses polycrystalline silicon has a lower leakage current ( The use of an OS transistor for the transistor M1 makes it possible to achieve extremely low off-state current. This allows the charge supplied to the node ND1 to be held for a long period of time.

[0219] In the circuit diagram shown in FIG. 12A, the liquid crystal element LC serves as a leak path for the data D1. Therefore, to perform the IDS drive properly, the resistivity of the liquid crystal element LC must be set to 1.0×10 1 4 It is preferable to set the resistance at Ω·cm or more.

[0220] Note that the channel region of the OS transistor contains, for example, In, Ga, and Zn. In, oxides, oxides containing In and Zn, etc. can be suitably used. A typical example of an oxide containing Ga and Zn is In:Ga:Zn=4:2:4.1. Compositions in the vicinity of [atomic ratio] can be used.

[0221] FIG. 12B shows signals applied to the signal line SL and the gate line GL in the normal drive mode. In the normal drive mode, the normal frame frequency (e.g. For example, 60 Hz. Fig. 12(B) shows periods T1 to T3. A scanning signal is applied to the gate line GL between the gate lines GL and data D1 is written to the node ND1 from the signal line SL. This operation is performed when the same data D1 is written from the period T1 to T3. The same applies when writing different data.

[0222] On the other hand, FIG. 12C shows that the signal line SL and the gate line GL in the IDS drive mode are 1 is a timing chart showing the waveform of a signal to be applied. One frame period is represented as period T1, during which data is written. The writing period is period T W , the data retention period is period T RET The IDS driving mode is Period T W A scanning signal is applied to the gate line GL, data D1 is written to the signal line SL, and during the period T RET The gate line GL is fixed to a low level voltage, and the transistor M1 is put into a non-conducting state. The data D1 that was written once is held. For example, the frequency may be set to be equal to or higher than 0.1 Hz and lower than 60 Hz.

[0223] This embodiment mode can be combined with other embodiment modes as appropriate.

[0224] (Embodiment 3) In this embodiment, an example of a method for driving a touch sensor will be described with reference to the drawings.

[0225] <Example of sensor detection method> FIG. 13A is a block diagram showing the configuration of a mutual capacitance type touch sensor. In FIG. 13A, a pulse voltage output circuit 551 and a current detection circuit 552 are shown. In A), an electrode 521 to which a pulse voltage is applied and an electrode 522 to which a change in current is detected are arranged. Each of these is shown as six wires, X1 to X6 and Y1 to Y6. FIG. 5A illustrates a capacitance 553 formed by overlapping an electrode 521 and an electrode 522. The functions of the electrodes 521 and 522 may be interchangeable.

[0226] The pulse voltage output circuit 551 is a circuit for applying a pulse voltage to the wirings X1 to X6 in order. A pulse voltage is applied to the wirings X1 to X6 to form a capacitance 553. An electric field is generated between the electrodes 521 and 522. The electric field generated between the electrodes is prevented by shielding or the like. The proximity or contact of the object to be detected is detected by causing a change in the mutual capacitance of the capacitance 553. It can be put out.

[0227] The current detection circuit 552 detects the current in the wirings Y1 to Y6 due to a change in mutual capacitance in the capacitor 553. This is a circuit for detecting changes in current. The wiring from Y1 to Y6 detects the proximity or When there is no contact, the detected current value does not change, but when the object to be detected approaches or comes into contact with the object, When the mutual capacitance decreases, the change in the current value is detected. This can be achieved by using an integrating circuit or the like.

[0228] In addition, one or both of the pulse voltage output circuit 551 and the current detection circuit 552 may be For example, the display unit 62 and the driving circuit unit 6 4, etc., can be formed simultaneously to simplify the process, and the This is preferable because it is possible to reduce the number of components required. One or both of the flow detection circuits 552 may be implemented in IC 73.

[0229] In particular, as a transistor formed on the substrate 51, a multi-layer structure is formed on a semiconductor layer in which a channel is formed. When crystalline silicon such as crystalline silicon or single crystal silicon is used, the pulse voltage output circuit 55 1 and the current detection circuit 552, etc., and improve the sensitivity of the touch sensor. It is possible.

[0230] FIG. 13B shows input / output waveforms in the mutual capacitance type touch sensor shown in FIG. 13A. FIG. 13B shows a timing chart of the detection of the object in each row and column during one frame period. In FIG. 13(B), the detection of the object to be detected is performed. The two cases shown are when detecting the object (touch) and when detecting the object (sensor). For the wiring to Y6, a waveform is shown in which the voltage value corresponds to the detected current value.

[0231] A pulse voltage is applied to the wires X1-X6 in sequence, and Y1 through The waveform on the Y6 wire changes. When there is no proximity or contact of the object to be detected, the waveform on the Y6 wire changes. The waveforms of Y1 to Y6 change uniformly in response to the change in the voltage of the wire 6. In areas where they are close to each other or in contact, the current value decreases, and the corresponding voltage waveform also changes. To become.

[0232] In this way, the proximity or contact of a sensing object can be detected by detecting the change in mutual capacitance. It is possible.

[0233] <Example of a method for driving a display device> FIG. 14A is a block diagram showing a configuration example of a display device. A driving circuit GD (scanning line driving circuit), a source driving circuit SD (signal line driving circuit), a plurality of pixels p ix. In FIG. 14A, the gate drive circuit GD is electrically The gate lines x_1 to x_m (m is a natural number) connected to the source driver circuit SD are electrically connected to the In the pixel pix, corresponding to the connected source lines y_1 to y_n (n is a natural number), They are numbered (1,1) through (n,m).

[0234] FIG. 14B shows the signals applied to the gate lines and source lines in the display device shown in FIG. FIG. 14B is a timing chart of a data signal for each frame period. The diagram shows two cases: when the data signal is rewritten and when it is not rewritten. 4(B) does not take into account periods such as blanking periods.

[0235] When the data signal is rewritten every frame period, the gate lines x_1 to x_m are In the horizontal scanning period 1H during which the scanning signal is at H level, A data signal D is applied to the column source lines y_1 to y_n.

[0236] When the data signal is not rewritten every frame period, the gate lines x_1 to x_m are In the horizontal scanning period 1H, the scanning signal to the source lines y_1 to y_n of each column is stopped. Stop giving data signals.

[0237] The driving method in which the data signal is not rewritten every frame period is particularly Effective when using an oxide semiconductor in the semiconductor layer in which a channel is formed as a transistor A transistor using an oxide semiconductor is different from a transistor using a semiconductor such as silicon. It is possible to reduce the off-state current significantly compared to that of a conventional transistor. The data signal written in the previous period is retained without rewriting the data signal for each period. For example, the gradation of a pixel can be maintained for 1 second or more, preferably 5 seconds or more. It is also possible.

[0238] In addition, a polycrystalline silicon is used as a semiconductor layer in which a channel is formed as a transistor of the pixel pix. When applying a recon, the size of the storage capacitance of the pixel is increased in advance. The larger the storage capacitance, the longer the pixel gray level can be maintained. The size of the storage capacitor can be determined by the size of the transistor and the display element electrically connected to the storage capacitor. It can be set according to the leakage current. For example, the retention capacitance per pixel should be set to 5 fF or more. pF or less, preferably 10 fF to 5 pF, more preferably 20 fF to 1 pF In this case, the data signal is not rewritten every frame period, but is written in the previous period. The data signal can be held, for example, for a period of several frames or several tens of frames. This makes it possible to maintain the gradation of the pixel.

[0239] <Example of how to drive the display and touch sensor> 15(A) to (D) show an example of the touch sensor described in FIG. 13(A) and (B). When the display unit described in FIG. 14(A) and (B) is driven for 1 second, FIG. 15(A) is a diagram for explaining the operation during a frame period in which one of the display units Frame period is 16.7 ms (frame frequency: 60 Hz), one frame of the touch sensor The period is shown to be 16.7 ms (frame frequency: 60 Hz).

[0240] In the display device according to one embodiment of the present invention, the operation of the display unit and the operation of the touch sensor are independent of each other. In this case, a touch detection period can be provided in parallel with a display period. As shown in the figure, the frame period of both the display and touch sensor is set to 16.7 ms (frame frequency The frame frequency of the touch sensor and the display can be set to 60Hz. For example, as shown in FIG. 15(B), one frame period of the display section may be set to 8. 3 ms (frame frequency: 120 Hz), and the frame period of the touch sensor is set to 16 It is also possible to set the frame rate to 0.7ms (frame frequency: 60Hz). The frame frequency of the portion may be set to 33.3 ms (frame frequency: 30 Hz).

[0241] The frame frequency of the display unit is switchable, and when displaying moving images, the frame Increase the frequency (for example, 60Hz or more or 120Hz or more) when displaying a still image. reduce the frame frequency (for example, 60Hz or less, 30Hz or less, or 1Hz or less). By doing so, the power consumption of the display device can be reduced. The frame frequency can be switched between standby and when a touch is detected. It is okay to do so.

[0242] In addition, the display device of one embodiment of the present invention can display the previous image without rewriting a data signal in a display portion. By holding the rewritten data signal for the period, one frame period of the display is extended to 16.7ms. Therefore, as shown in FIG. 15(C), The frame period is set to 1 sec. (frame frequency: 1 Hz), and the touch sensor The frame period can also be set to 16.7 ms (frame frequency: 60 Hz).

[0243] In addition, the data signal rewritten in the previous period is not rewritten in the display unit. For the configuration to hold the signal, refer to the IDS drive mode described above. In the IDS drive mode, the rewriting of data signals in the display is limited to a specific area. A partial IDS driving mode may be used in which only the display part is driven. The data signal that is to be written is rewritten only in a specific area, and in other areas, the data signal is written to the previous period. This is a configuration for holding the rewritten data signal.

[0244] According to the touch sensor driving method disclosed in the present embodiment, the driving method shown in FIG. When the touch sensor is operated continuously, the touch sensor can be driven continuously. ) at the timing when the touch sensor detects the proximity or contact of the object to be detected. It is also possible to rewrite the data signals on the display unit.

[0245] Here, if a data signal rewrite operation is performed on the display unit during the sensing period of the touch sensor, Noise generated when rewriting data signals is transmitted to the touch sensor, causing the Therefore, the rewriting period of the data signal on the display unit and It is preferable to drive the touch sensor so that the sensing period of the touch sensor is shifted from the sensing period of the touch sensor.

[0246] In FIG. 16A, the rewriting of the data signal of the display unit and the sensing of the touch sensor are interchanged. FIG. 16B shows an example in which the rewriting operation of the data signal on the display unit is performed. This shows an example in which the touch sensor is sensed once for every two times. A configuration in which the touch sensor is sensed once for every three or more rewrite operations. It is also possible to use the following.

[0247] In addition, the transistor applied to the pixel pix has an oxide in the semiconductor layer in which the channel is formed. When using semiconductors, it is possible to reduce the off-current significantly, making it possible to rewrite data signals. Specifically, after the data signal is rewritten, Therefore, it is possible to provide a sufficiently long pause before the data signal is rewritten next time. The pause period can be, for example, 0.5 seconds or more, 1 second or more, or 5 seconds or more. The upper limit of the pause period is limited by the capacitance connected to the transistor and the leakage current of the display element, etc. For example, the duration may be limited to 1 minute or less, 10 minutes or less, 1 hour or less, or 1 day or less. can be done.

[0248] FIG. 16C shows an example in which the data signal of the display is rewritten once every 5 seconds. In FIG. 16(C), the display unit rewrites the data signal and then writes the next data signal. Before the rewrite operation, a pause period is provided during which the rewrite operation is stopped. So, the touch sensor operates at a frame frequency of iHz (i is the frame frequency of the display device or higher, In addition, as shown in Figure 16(C), the touch panel can be driven at a frequency of 0.2 Hz or more. The sensor performs sensing during the rest period, and does not perform sensing during the period when the data signal of the display is being rewritten. This is preferable because it is possible to improve the sensitivity of the touch sensor. As shown in Fig. 1, the data signal of the display unit is rewritten and the touch sensor is sensed at the same time. This allows the driving signals to be simplified.

[0249] In addition, during the pause period when the data signal of the display unit is not rewritten, the data signal to the display unit is In addition to stopping the supply of the signal, either one of the gate driver GD and the source driver SD is In addition, the gate driver GD and the source driver SD may both be stopped. You can also stop the power supply to one or both of them. This will reduce noise. This reduces the power consumption of the display device and improves the sensitivity of the touch sensor. Power consumption can be further reduced.

[0250] The display device according to one embodiment of the present invention has a structure in which a display unit and a touch sensor are sandwiched between two substrates. Therefore, the distance between the display unit and the touch sensor can be made extremely short. Noise generated when the display is in operation is easily transmitted to the touch sensor, reducing the sensitivity of the touch sensor. By applying the driving method exemplified in this embodiment, it is possible to achieve a thin and high It is therefore possible to realize a display device having a touch sensor that achieves both high detection sensitivity and high image quality.

[0251] This embodiment mode can be combined with other embodiment modes as appropriate.

[0252] (Embodiment 4) In this embodiment, the present invention can be used for a semiconductor layer of a transistor disclosed in one embodiment of the present invention. In addition, a metal oxide is used for the semiconductor layer of a transistor. In this case, the metal oxide may be interpreted as an oxide semiconductor.

[0253] Oxide semiconductors are classified into single-crystal oxide semiconductors and non-single-crystal oxide semiconductors. As a crystalline oxide semiconductor, CAAC-OS (c-axis-aligned crystal-like oxide semiconductor) talline oxide semiconductor), polycrystalline oxide semiconductor, n c-OS(nanocrystalline oxide semiconductor ), pseudo-amorphous oxide semiconductor (a-like OS) xide semiconductor, and amorphous oxide semiconductor.

[0254] In addition, the semiconductor layer of the transistor disclosed in one embodiment of the present invention may include CAC-OS (Clo ud-Aligned Composite oxide semiconductor ) may also be used.

[0255] Note that the semiconductor layer of the transistor disclosed in one embodiment of the present invention is preferably a semiconductor layer formed of the above-described non-single-crystal oxide. In addition, a non-single-crystal oxide semiconductor or a CAC-OS can be preferably used. As the OS, nc-OS or CAAC-OS can be preferably used.

[0256] Note that in one embodiment of the present invention, CAC-OS is preferably used for a semiconductor layer of a transistor. By using CAC-OS, it is possible to provide transistors with high electrical characteristics and high reliability. It can be granted.

[0257] The following provides details about CAC-OS.

[0258] CAC-OS or CAC-metal oxide is a material that has the function of electrical conductivity. A part of the material has an insulating function, and the material as a whole has a semiconductor function. Note that CAC-OS or CAC-metal oxide is used as the channel of a transistor. When used in a forming region, the conductive function is to allow the flow of electrons (or holes) that serve as carriers. The insulating function is to prevent the flow of electrons, which act as carriers. The function of switching (O Add the function to turn the power on / off to CAC-OS or CAC-metal oxide. In the case of CAC-OS or CAC-metal oxide, By separating these functions, the functionality of both can be maximized.

[0259] In addition, CAC-OS or CAC-metal oxide has a conductive region and an insulating region. The conductive region has the above-mentioned conductive function, and the insulating region has the above-mentioned insulating function. In addition, the conductive and insulating regions in the material are formed at the nanoparticle level. In addition, the conductive and insulating regions may be separated by a metal. In addition, the conductive area may be observed as a cloud-like connected area with a blurred periphery. There may be cases where this occurs.

[0260] In addition, in the CAC-OS or CAC-metal oxide, the conductive region and the insulating region are The peripheral region is 0.5 nm to 10 nm, preferably 0.5 nm to 3 nm. The following sizes may be present in the material:

[0261] In addition, CAC-OS or CAC-metal oxide has different band gaps. For example, CAC-OS or CAC-metal oxi de is a component with a wide gap due to the insulating region and a component with a narrow gap due to the conductive region. In the case of this configuration, when a carrier flows, In the narrow gap component, carriers mainly flow. The component having a narrow gap acts complementary to the component having a wide gap. Carriers also flow to the wide gap component in conjunction with the component with a large gap. AC-OS or CAC-metal oxide is placed in the channel formation region of the transistor. When used, the transistor has a high current driving force in the on-state, i.e., a large on-current. And high field effect mobility can be obtained.

[0262] That is, CAC-OS or CAC-metal oxide is a matrix composite material. (matrix composite) or metal matrix composite (metal matrix It can also be called atrix composite.

[0263] For example, the elements constituting the metal oxide in CAC-OS are 0.5 nm or more and 10 nm or less. Preferably, the material is unevenly distributed in a size range of 1 nm to 2 nm or in the vicinity thereof. In the following, it is assumed that one or more metal elements are unevenly distributed in a metal oxide. The region having the metal element has a size of 0.5 nm to 10 nm, preferably 1 nm to 2 nm. A mixed state in which the size is less than or close to one m is also called a mosaic or patch pattern.

[0264] The metal oxide preferably contains at least indium. It is preferable that the metal contains zinc. In addition to the above, aluminum, gallium, yttrium, Aluminum, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium nium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum One or more of the following are included: tungsten, magnesium, etc. It's fine.

[0265] For example, CAC-OS made of In-Ga-Zn oxide (In-Ga-Zn oxide is one of the CAC-OS) a-Zn oxide may be specifically referred to as CAC-IGZO. (Hereinafter, InO X1 (X1 is a real number greater than 0.) or indium zinc oxide compound (hereinafter referred to as In X2 Zinc Y2 O Z2 (X2, Y2, and Z2 are real numbers greater than 0) ) and gallium oxide (GaO X3 (X3 is a real number greater than 0). ), or gallium zinc oxide (Ga X4 Zinc Y4 O Z4 (X4, Y4, and Z4 (is a real number greater than 0).) The material is separated into a mosaic shape, Mosaic InO X1 , or In X2 Zinc Y2 O Z2 is uniformly distributed in the film (Hereinafter, this will also be referred to as cloud-like.)

[0266] In other words, CAC-OS is X3 The region where In is the main component and X2 Zinc Y2 O Z2 , or InO X1 A composite metal oxide having a structure in which a region in which In this specification, for example, the atomic ratio of In to the element M in the first region is The first region has an atomic ratio of In to the element M in the second region that is greater than the atomic ratio of In in the second region. The concentration of In is higher than in the region

[0267] Note that IGZO is a common name and refers to a compound made of In, Ga, Zn, and O. A typical example is InGaO3(ZnO). m1 (m1 is a natural number), or In (1 +x0) Ga (1-x0) O3(ZnO) m0 (-1≦x0≦1, m0 is an arbitrary number) Examples of such crystalline compounds include those that are

[0268] The crystalline compounds may have a single crystal structure, a polycrystalline structure, or a c-axis aligned crystal structure (CAAC). The CAAC structure is a structure in which multiple IGZO The nanocrystals have a c-axis orientation and are connected in ab-plane without being oriented. do.

[0269] On the other hand, CAC-OS is a material structure of metal oxide. CAC-OS is a material structure of In, Ga In the material composition containing Zn, and O, nanoparticles mainly composed of Ga were observed in some parts. The regions where the In is mainly contained are observed as nanoparticles, and the regions where the In is mainly contained as nanoparticles are observed. Therefore, in the CAC-OS, the crystal structure is a secondary element.

[0270] It should be noted that the CAC-OS does not include a laminated structure of two or more films having different compositions. For example, a structure consisting of two layers, a film mainly made of In and a film mainly made of Ga, is not included. do not have.

[0271] In addition, GaO X3 The region where In is the main component and X2 Zinc Y2 O Z2 , or InO X1 but In some cases, a clear boundary between the region of the main component and the region of the main component may not be observed.

[0272] Instead of gallium, aluminum, yttrium, copper, vanadium, and beryllium can be used. , boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum , lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium If one or more selected types of sodium, etc. are included, CAC-OS will The region observed is a nanoparticle of the metal element as the main component, and the region observed is a nanoparticle of In as the main component. The nanoparticle-like regions are randomly distributed in a mosaic pattern. say.

[0273] CAC-OS is formed by sputtering without intentionally heating the substrate. In addition, when the CAC-OS is formed by a sputtering method, the deposition gas and The gas to be used should be selected from an inert gas (typically argon), oxygen gas, and nitrogen gas. In addition, the ratio of oxygen gas to the total flow rate of the deposition gas during deposition may be For example, the flow rate ratio of oxygen gas is preferably 0% or more and less than 30%. It is preferable that the content be 0% or more and 10% or less.

[0274] CAC-OS is a type of X-ray diffraction (XRD) measurement method. When measured using the θ / 2θ scan by the out-of-plane method, In other words, no clear peaks are observed in the measurement region from the X-ray diffraction. It can be seen that no orientation in the ab plane direction or the c-axis direction is observed.

[0275] In addition, the CAC-OS uses an electron beam with a probe diameter of 1 nm (also called a nano-beam electron beam). In the electron beam diffraction pattern obtained by irradiating the sample with electrons, a ring-shaped region of high brightness and the Therefore, the electron diffraction pattern indicates that the CAC-OS The crystal structure is nc (nano-crystal) which has no orientation in the planar direction and cross-sectional direction. It can be seen that it has a crystalline structure.

[0276] For example, in the case of CAC-OS made of In-Ga-Zn oxide, energy dispersive X-ray Spectroscopy (EDX: Energy Dispersive X-ray spectroscopy) The EDX mapping obtained using a GaO X3 The region where is the main component and , In X2 Zinc Y2 O Z2 , or InO X1 The areas where the main component is It can be confirmed that the compound has the structure shown in FIG.

[0277] CAC-OS has a structure different from that of IGZO compounds in which metal elements are uniformly distributed. It has different properties from ZO compounds. That is, CAC-OS is GaO X3 The main ingredients are In a certain area, X2 Zinc Y2 O Z2 , or InO X1 The region where is the main component and The phase is separated into two layers, and the regions each containing one element as a main component are arranged in a mosaic pattern.

[0278] Here, In X2 Zinc Y2 O Z2 , or InO X1 The area where GaO is the main component X3 This region has a higher electrical conductivity than the region where In is the main component. X2 Zinc Y 2O Z2 , or InO X1 The carriers flow through the area where the main component is oxidized. Therefore, the conductivity of In is expressed as a semiconductor. X2 Zinc Y2 O Z2 , or InO X The region where 1 is the main component is distributed in a cloud-like shape in the oxide semiconductor, which results in a high electric field effect. Mobility (μ) can be achieved.

[0279] On the other hand, GaO X3 The region where the main components are In X2 Zinc Y2 O Z2 , or InO X This region has higher insulating properties than the region where GaO X3 etc. The distribution of the main component in the oxide semiconductor suppresses leakage current and provides good switching performance. Switching operation can be achieved.

[0280] Therefore, when CAC-OS is used in a semiconductor device, GaO X3 Insulation caused by In X2 Zinc Y2 O Z2 , or InO X1 The conductivity caused by the This results in a high on-state current (I on ) and high field-effect mobility (μ) can be achieved. Cut.

[0281] In addition, semiconductor devices using CAC-OS have high reliability. It is ideal for a variety of semiconductor devices, including displays.

[0282] This embodiment mode can be combined with other embodiment modes as appropriate.

[0283] (Embodiment 5) In this embodiment, an electronic device according to one embodiment of the present invention will be described.

[0284] Examples of electronic devices include television sets, desktop or notebook PCs, etc. Computers, monitors for computers, digital cameras, digital video cameras Cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, audio playback Examples of such devices include large gaming machines such as pachinko machines.

[0285] 17(A) to (C) show a mobile information terminal. The mobile information terminal of this embodiment is, for example, The device has one or more functions selected from the group consisting of a telephone, a notebook, and an information viewing device. Specifically, it can be used as a smartphone or a smart watch. The mobile information terminals in this form can perform functions such as mobile phone calls, e-mail, text browsing and writing, music playback, It can run various applications such as video playback, Internet communication, and games. The portable information terminals shown in Figs. 17(A) to 17(C) can have various functions. For example, functions to display various information (still images, videos, text images, etc.) on the display, Touch panel function, calendar, date or time display function, various software (Program-based) processing control function, wireless communication function, and various Functions for connecting to computer networks and transmitting various data using wireless communication functions or receiving functions, reading out programs or data recorded on a recording medium The mobile phone shown in Fig. 17(A) to (C) may have a function of displaying information on a display unit. The functions of the portable information terminal are not limited to these, and the portable information terminal may have other functions.

[0286] The portable information terminals shown in Figs. 17(A) to (C) are used for mobile phone calls, e-mail, and text browsing and creation. It supports a variety of applications such as music playback, Internet communication, and computer games. In addition, the mobile information terminals shown in FIGS. 17(A) to 17(C) are compliant with the communication standard For example, a wristwatch-type wireless communication device as shown in FIG. The portable information terminal 820 communicates with a headset capable of wireless communication to You can also make calls nose-free.

[0287] The mobile information terminal 800 shown in FIG. 17A includes a housing 811, a display unit 812, and an operation button 81. 3, an external connection port 814, a speaker 815, a microphone 816, etc. The display unit 812 of the 00 has a flat surface.

[0288] A portable information terminal 810 shown in FIG. 17B includes a housing 811, a display unit 812, and an operation button 81. 3, an external connection port 814, a speaker 815, a microphone 816, a camera 817, etc. The display unit 812 of the portable information terminal 810 has a curved surface.

[0289] FIG. 17C shows a wristwatch-type mobile information terminal 820. The mobile information terminal 820 has a housing 8 11, a display unit 812, a speaker 815, an operation key 818 (power switch or operation switch The display unit 812 of the portable information terminal 820 has a circular outer shape. The display unit 812 of the information terminal 820 has a flat surface.

[0290] The display device of one embodiment of the present invention can be used for the display portion 812. It is possible to manufacture a portable information terminal having a display portion with high light transmission.

[0291] The mobile information terminal of this embodiment is provided with a touch sensor on the display unit 812. Any operation such as inputting characters is performed by touching the display unit 812 with a finger or a stylus. This can be done by

[0292] In addition, the operation button 813 is operated to turn the power on and off, and to display information on the display unit 812. For example, you can change the type of image displayed on the main screen from the email composition screen. You can switch to the menu screen.

[0293] In addition, a detection device such as a gyro sensor or an acceleration sensor is provided inside the portable information terminal. By doing so, the orientation of the portable information terminal (portrait or landscape) is determined, and the orientation of the screen display of the display unit 812 is adjusted. The screen display orientation can be switched automatically. The operation can be performed by touching, operating the operation button 813, or by voice input using the microphone 816. It is also possible.

[0294] A television set 7100 shown in FIG. 18A includes a housing 7101 and a display unit 7102. The display portion 7102 can display images. The display device can be used for the display portion 7102. In this embodiment, a television set having the above-mentioned structure can be manufactured. 7 shows a configuration in which the housing 7101 is supported by the bracket 7102.

[0295] The television device 7100 can be operated using an operation switch provided on the housing 7101 or a separate remote control. This can be done by the remote control operation device 7111. This allows you to control the channel and volume, and the image displayed on the display unit 7102 In addition, the remote control operation device 7111 can be operated. A display unit for displaying information output from the

[0296] The television device 7100 includes a receiver and a modem. It is possible to receive more general television broadcasts, and furthermore, to receive them by wire or wirelessly via a modem. By connecting to a communication network, It is also possible to communicate information between followers and recipients, or between recipients themselves.

[0297] The computer 7200 shown in FIG. 18B includes a main body 7201, a housing 7202, a display unit 72 03, keyboard 7204, external connection port 7205, pointing device 7206 Note that the computer uses the display device of one embodiment of the present invention as the display portion 7203. This makes it possible to create a computer with a display with a high aperture ratio. It can be manufactured.

[0298] The camera 7300 shown in FIG. 18C includes a housing 7301, a display unit 7302, and an operation button 73. The camera 7300 also has a detachable lens. The 7306 is attached.

[0299] The display device of one embodiment of the present invention can be used for the display portion 7302. Cameras can be made with high efficiency displays.

[0300] Here, the camera 7300 and the lens 7306 are detached from the housing 7301 and replaced. However, the lens 7306 and the housing 7301 may be integrated together.

[0301] The camera 7300 takes still or moving images by pressing the shutter button 7304. In addition, the display portion 7302 has a function as a touch panel. It is also possible to capture an image by touching 7302.

[0302] In addition, the camera 7300 can be equipped with a strobe device, viewfinder, etc. Alternatively, these may be incorporated into the housing 7301.

[0303] This embodiment mode can be combined with other embodiment modes as appropriate. EXAMPLES

[0304] In this example, a cross-sectional structure of a display portion and a scanning line driver circuit portion of a display device according to one embodiment of the present invention was examined. The light transmittance of the contact area between the transistor and pixel electrode in the display area was evaluated. The results will be explained.

[0305] FIG. 19 shows a cross-sectional structure of a display section and a scanning line driving circuit section of the display device of this embodiment.

[0306] The display device shown in FIG. 19 is an example of a transmissive liquid crystal display device using a vertical electric field type liquid crystal element. be.

[0307] As shown in FIG. 19, the display device includes a substrate 51, a transistor 201, a transistor 206, and a , a liquid crystal element 40, a capacitance element 219, an alignment film 133a, an alignment film 133b, a connection portion 204, a connection The adhesive layer 141, the colored layer 131, the light-shielding layer 132, the overcoat 121, the substrate 61, and the polarizing The plate 130 and the like.

[0308] The display portion 62 includes a transistor 206 , a liquid crystal element 40 , and a capacitor 219 .

[0309] The transistor 206 includes a gate 221, an insulating layer 213, a conductive layer 222a, and a conductive layer 222c. , and a semiconductor layer 231.

[0310] The conductive layer 222a and the conductive layer 222c are each connected to the semiconductor layer 231.

[0311] The liquid crystal element 40 is a liquid crystal element to which the VA mode is applied. The liquid crystal layer 113 has a pixel electrode 111, a common electrode 112, and a liquid crystal layer 113. It is located between the common electrodes 112 .

[0312] The pixel electrode 111 is connected to the semiconductor layer 23 of the transistor 206 through the conductive layer 222c. 1 is electrically connected to

[0313] The conductive layer 222c functions as one of a pair of electrodes of the capacitor 219. The conductive layer 222c serves as the other of the pair of electrodes of the capacitor 219. The conductive layer 217a overlaps with the insulating layer 213. is connected.

[0314] Here, the semiconductor layer 231, the conductive layer 222c, the conductive layer 217a, the conductive layer 217b, and the conductive The layer 218 is made of a conductive material that transmits visible light. The conductive layer 218 and the conductive layer 222c can be formed in the same process and using the same material. The pixel electrode 111 and the transistor 112 can be formed in the same process and with the same material. A contact portion of the transistor 206, a contact portion between the conductive layer 217b and the conductive layer 218, and The capacitance element 219 can be disposed in the display region 68. Therefore, the aperture ratio can be increased. This can be done.

[0315] An example of a material and a method for forming each layer of the transistor 206 shown in FIG. 19 will be described. do.

[0316] First, a conductive film that transmits visible light (e.g., I TSO) is formed, and then a Cu film or the like is formed as a gate 221 by sputtering. The metal film also functions as a scanning line. Thus, gate wiring for transistors in the peripheral circuits can also be formed in the same process.

[0317] Next, a silicon nitride film and a silicon oxynitride film are formed as an insulating layer 213, which is a gate insulating layer. Next, a semiconductor layer 231 is formed by laminating CAC The CAC-OS film is then laminated with a CAAC-OS film. By forming a CAAC-OS film with high plasma resistance, Next, the conductive layer 231, which is a source electrode or a drain electrode, is As the conductive layer 222c, an indium zinc oxide film is formed by sputtering. The semiconductor layer 231 and the conductive layer 222c are each formed by wet etching. In order to prevent the semiconductor layer 231 from being etched when the conductive layer 222c is formed, In order to increase the selection ratio, a material different from that used for forming the semiconductor layer 231 is used in the etching solution. It is preferable to use the indium zinc oxide film in the same process. A layer 218 may also be formed.

[0318] Next, a metal film such as a Cu film is formed as the signal line and the conductive layer 222a by sputtering. In addition, the metal film is used to form a transistor in a peripheral circuit in the same process. Source and drain wiring may also be formed.

[0319] Next, the insulating layer 212 and the insulating layer 214, which are passivation films, are deposited by a PECVD apparatus. A silicon oxynitride film and a silicon nitride film are laminated using a silicon nitride film. As the functional insulating layer 215, acrylic resin is applied and an opening (contact opening) is formed. Then, an ITO film is formed as the pixel electrode 111.

[0320] The gate electrode of the transistor in the pixel is made of the Cu film formed as the scan line. This allows the light from the backlight to be irradiated onto the channel formation region. In FIG. 7, the contact between the transistor 206 and the pixel electrode 111 is The portion and the capacitor element 219 are configured to be able to transmit visible light.

[0321] A laminated structure that can be used for the region 139 in FIG. 19 is fabricated, and the light transmittance is measured. The results are shown in FIG. 20. Note that FIG. 20 also shows the light transmittance of glass (substrate 51). The transmittance was measured using a spectrophotometer U-4100 (Hitachi High-Tech Science Corporation). The measurements were performed using a meter (manufactured by the company).

[0322] As shown in FIG. 20, in one embodiment of the present invention, a laminated structure formed to increase the aperture ratio It was confirmed that the transistor 206 and the pixel electrode 1 transmit visible light. The contact portion with the semiconductor device 11 and the capacitance element 219 are formed using a material that transmits visible light. This suggests that the power consumption of the backlight can be reduced. EXAMPLES

[0323] In this example, a cross-sectional structure of a display portion and a scanning line driver circuit portion of a display device according to one embodiment of the present invention was examined. We will discuss the results of evaluating the light transmittance of the transistors arranged in the display area. do.

[0324] Figures 21(A1), (B1), (C1) and Figures 22(A1), (B1), (C1), (D1) ) will be used to describe a method for manufacturing a transistor included in a display portion of a display device of this embodiment. Figures 21(A2), (B2), (C2) and Figures 22(A2), (B2), (C2), (D2) ) to fabricate a transistor included in a scanning line driver circuit of a display device of this embodiment. explain.

[0325] First, a conductive layer 217s is formed on the substrate 51, and a conductive layer 224s is formed on the conductive layer 217s. (FIGS. 21(A1) and 21(A2)). The conductive layer 217s is made of a conductive material ( For example, the conductive layer 224s is formed using ITSO. The conductive layer 224s is formed using a material such as a metal, which is more preferable than the conductive layer 217s. For example, the conductive layer 224s is preferably formed of a conductive material having a lower resistance than the conductive layer 224b. Then, a metal film such as a Cu film is formed by using a sputtering method.

[0326] Next, the conductive layer 217s and the conductive layer 224s are processed to form a gate (FIG. 21(B1) In the display area, an island-shaped conductive layer 217 is formed (FIG. 21(B1)). In the moving circuit section, a laminated structure of an island-shaped conductive layer 217 and an island-shaped conductive layer 224 is formed (FIG. 2 1(B2)). A multi-tone mask (half-tone mask, gray-tone mask) is used to form the gate. It is preferable to use a multi-tone mask. A gate that transmits visible light is formed in the display section, and a gate with low resistance and a and gate wiring can be formed.

[0327] Next, an insulating layer 213 that functions as a gate insulating layer is formed, and a semiconductor layer 2 is formed on the insulating layer 213. In this embodiment, the insulating layer 213 is made of a nitride. In this embodiment, the semiconductor layer 23 is formed by stacking a silicon oxynitride film and a silicon oxynitride film. 1, a CAC-OS film and a CAAC-OS film were laminated by sputtering. A CAAC-OS film with high chemical and plasma resistance is formed on the CAC-OS film. This makes it possible for the semiconductor layer 231 to be less susceptible to damage during the process of manufacturing a transistor. By using an oxide semiconductor, the semiconductor layer 231 that transmits visible light can be formed.

[0328] Next, a conductive layer 222s is formed, and a conductive layer 222t is formed on the conductive layer 222s (FIG. 22 The conductive layer 222s is formed using a conductive material that transmits visible light. In this embodiment, an indium zinc oxide film is formed as the conductive layer 222s. The conductive layer 222t is formed using a conductive material, such as a metal, that has a lower resistance than the conductive layer 222s. is preferred.

[0329] Next, the conductive layer 222s and the conductive layer 222t are processed to form a source and a drain (FIG. 22(B1), (B2)). The display section and the scanning line driving circuit section each include a semiconductor layer 231. 22. The island-shaped conductive layer 222b and the island-shaped conductive layer 222c are formed so as to be connected to a part of the conductive layer 222b. In the display section, the conductive layer 222t remains in an island-shaped conductive layer. Only the island-shaped conductive layer 222a is connected to a part of the layer 222b, and most of the transistor On the other hand, the scanning line driving circuit section has a structure in which the visible light is transmitted through the pixel. A conductive layer 222t is processed on the island-shaped conductive layer 222b and the island-shaped conductive layer 222c. The island-shaped conductive layer 222a and the island-shaped conductive layer 222d are formed by the above steps (FIG. 22). (B2)) To form the source and drain, a multi-tone mask is used, just like to form the gate. It is preferable that the multi-tone mask is used. A source and a drain that transmit visible light are formed, and a source and a drain with low resistance are formed in the driving circuit part. The semiconductor layer 231, the source wiring, and the drain wiring can be formed. The source and drain can be formed by wet etching. In order to increase the selection ratio so that the semiconductor layer 231 is not etched when the etch is formed, It is preferable to use a different material for the mixing solution from that used for forming the semiconductor layer 231.

[0330] Next, an insulating layer 212 that functions as a gate insulating layer is formed, and a gate 22 is formed on the insulating layer 212. The gate 223 is formed using a conductive material that transmits visible light. In the example, the insulating layer 212 is formed by depositing a silicon oxynitride film and a silicon nitride film using a PECVD apparatus. As shown in Fig. 22(C1) and (C2), the gate 223 is Alternatively, the second pixel may be provided only in the scanning line driving circuit section. The gate 223 may be provided in both the display section and the scanning line driving circuit section.

[0331] Through the above steps, a transistor included in the display device of this embodiment can be manufactured.

[0332] A laminated structure that can be used in the region 140 in FIG. 22(C1) is fabricated, and the light transmission The results of measuring the optical efficiency are shown in FIG. 23. Note that FIG. 23 shows the optical efficiency of glass (substrate 51). The transmittance is also shown. The transmittance was measured using a spectrophotometer U-4100 (Hitachi High-Technologies Corporation). Measurements were performed using a fluoroscopy (manufactured by Jens).

[0333] As shown in FIG. 23, in one embodiment of the present invention, a laminated structure formed to increase the aperture ratio It was confirmed that visible light could be transmitted through the display. By forming the backlight using a material that transmits visible light, it is possible to reduce the power consumption of the backlight. It was suggested that this could be done. [Explanation of symbols]

[0334] 34 Capacitive element 40 Liquid crystal element 45 light 51 Substrate 61 Substrate 62 Display section 63 Connection 64 Drive circuit section 65 Wiring 66 Hidden area 68 Display area 72 FPC 72a FPC 72b FPC 73 IC 73a IC 73b IC 81 scan lines 82 Signal Line 100A display device 100B display device 100C display device 100D display device 111 Pixel electrode 112 Common electrode 113 Liquid crystal layer 121 Overcoat 127 Electrode 128 electrode 130 Polarizing Plate 131 Colored layer 132 Light blocking layer 133a Alignment film 133b Alignment film 137 Wiring 138 Wiring 139 areas 140 areas 141 Adhesive layer 162 Substrate 201 Transistor 204 Connection 206 Transistor 212 Insulating layer 213 Insulating Layer 214 Insulating layer 215 Insulating Layer 217 Conductive Layer 217a Conductive layer 217b Conductive layer 217s conductive layer 218 Conductive Layer 219 Capacitive element 220 Insulating layer Gate 221 222a conductive layer 222b Conductive layer 222c conductive layer 222d conductive layer 222s conductive layer 222t conductive layer Gate 223 224 Conductive Layer 224s conductive layer 228 scan lines 229 Signal Line 231 Semiconductor Layer 231a First metal oxide layer 231b Second metal oxide layer 242 Connectors 244 Capacitive Line 251 Conductive Layer 350A Touch Panel 350B Touch Panel 370 Display device 375 Input Device 376 Input Devices 379 Display device 501 Display element 506 Pixel Circuit 521 Electrode 522 Electrode 551 Pulse voltage output circuit 552 Current detection circuit 553 capacity 800 Mobile Information Terminals 810 Mobile Information Terminal 811 Case 812 Display section 813 Operation button 814 External connection port 815 Speaker 816 Mike 817 Camera 818 Operation Key 820 Mobile Information Terminal 7100 Television equipment 7101 Case 7102 Display section 7103 Stand 7111 Remote control device 7200 Computer 7201 Main unit 7202 Case 7203 Display section 7204 Keyboard 7205 External connection port 7206 Pointing Device 7300 Camera 7301 Case 7302 Display section 7303 Operation button 7304 Shutter button 7306 Lens

Claims

1. A pixel electrode electrically connected to a transistor, a semiconductor layer in which a channel of the transistor is formed includes an oxide semiconductor layer, one of a source electrode and a drain electrode of the transistor has a conductive layer having a function of transmitting visible light; the other of the source electrode and the drain electrode of the transistor has a conductive layer having a function of blocking visible light; the conductive layer having a function of transmitting visible light has a region in contact with the pixel electrode, the conductive layer having a function of blocking visible light has a function of inputting a data signal, The conductive film having a function of transmitting visible light contains hydrogen.

2. In claim 1, The display device, wherein the oxide semiconductor layer contains one or more of indium, aluminum, gallium, yttrium, tin, and zinc.

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