Display device, module, and electronic device

Abstract

An embodiment of the present invention provides a high-definition liquid crystal display device. A liquid crystal display device with a high aperture ratio is provided. A liquid crystal display device with a high contrast ratio and display quality is provided. A liquid crystal display device capable of low-voltage driving is provided. The display device includes a pixel electrode, a first common electrode, a second common electrode, and a liquid crystal layer between a pair of substrates. The pixel electrode and the first common electrode are between one of the substrates and the liquid crystal layer. The second common electrode is between the other of the substrates and the liquid crystal layer. The same potential is supplied to the first common electrode and the second common electrode. The first common electrode includes a portion overlapping the second common electrode between display regions of two adjacent sub-pixels that exhibit different colors. At least one of the pixel electrode and the first common electrode includes a portion that does not overlap the second common electrode in the display region of the sub-pixel.

Description

[0001] This application is a divisional application of the application filed on March 6, 2017, with international application number PCT / IB2017 / 051278, which entered the Chinese national phase on September 13, 2018, entitled "Display Device, Module and Electronic Device", with national application number 201780017003.8. Technical Field

[0002] One embodiment of the present invention relates to a liquid crystal display device, module, and electronic device.

[0003] Note that one embodiment of the present invention is not limited to the above-described technical fields. Examples of technical fields for one embodiment of the present invention include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting devices, input devices (touch sensors, etc.), input / output devices (touch panels, etc.), methods for driving them, and methods for manufacturing them. Background Technology

[0004] Most transistors used in flat panel displays, such as liquid crystal displays and light-emitting displays, are formed using silicon semiconductors such as amorphous silicon, monocrystalline silicon, and polycrystalline silicon, which are disposed on a glass substrate. Transistors using the aforementioned silicon semiconductors are used in integrated circuits (ICs), etc.

[0005] In recent years, the technology of using metal oxides exhibiting semiconductor properties instead of silicon semiconductors in transistors has attracted attention. Note that in this specification, metal oxides exhibiting semiconductor properties are referred to as oxide semiconductors. For example, Patent Documents 1 and 2 disclose technologies for manufacturing transistors using zinc oxide or In-Ga-Zn type oxides as oxide semiconductors and using such transistors as switching elements in pixels of display devices.

[0006] [References]

[0007] [Patent Literature]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2007-123861

[0009] [Patent Document 2] Japanese Patent Application Publication No. 2007-096055 Summary of the Invention

[0010] One objective of this invention is to provide a high-definition liquid crystal display device. Another objective of one embodiment of this invention is to provide a liquid crystal display device with a high aperture ratio. Another objective of one embodiment of this invention is to provide a liquid crystal display device with high contrast and display quality. Another objective of one embodiment of this invention is to provide a liquid crystal display device capable of low-voltage driving. Another objective of one embodiment of this invention is to provide a liquid crystal display device with low power consumption. Another objective of one embodiment of this invention is to provide a highly reliable liquid crystal display device. Another objective of one embodiment of this invention is to provide a novel liquid crystal display device.

[0011] Note that the description of the above objectives does not preclude the existence of other objectives. In one embodiment of the invention, it is not necessary to achieve all of the above objectives. Objectives other than those described above can be extracted from the description, drawings, claims, etc.

[0012] A display device according to one embodiment of the present invention includes a pixel electrode, a first common electrode, a second common electrode, and a liquid crystal layer between a pair of substrates. The pixel electrode and the first common electrode are located between one of the substrates and the liquid crystal layer. The second common electrode is located between the other of the substrates and the liquid crystal layer. The first and second common electrodes are supplied with the same potential. The first common electrode includes a portion overlapping the second common electrode between the display areas of two adjacent sub-pixels displaying different colors. At least one of the pixel electrode and the first common electrode includes a portion in the display area of ​​a sub-pixel that does not overlap with the second common electrode.

[0013] The second common electrode preferably includes an opening in the display area of ​​the sub-pixel. When the thickness of the liquid crystal layer is represented by d, the width of the opening is preferably d / 6 or more and narrower than the width of the sub-pixel. When the thickness of the liquid crystal layer is represented by d, the spacing between the openings is preferably d or more and 2.5d or less. The thickness d of the liquid crystal layer is preferably 1 μm or more and 3 μm or less.

[0014] The first common electrode can be electrically connected to the second common electrode. Alternatively, the first and second common electrodes can be supplied with potential independently. For example, the first and second common electrodes can be electrically connected to different power lines.

[0015] The liquid crystal contained in the liquid crystal layer preferably has negative dielectric anisotropy.

[0016] The aforementioned display device preferably includes a transistor comprising an oxide semiconductor in its channel formation region. This transistor is electrically connected to a pixel electrode. The semiconductor layer of the transistor preferably comprises, for example, one of aluminum, gallium, yttrium, and tin, indium, and zinc.

[0017] Preferably, the above-mentioned display device includes scan lines and signal lines, the extension direction of the scan lines intersects the extension direction of the signal lines, and the arrangement direction of multiple sub-pixels of the same color intersects the extension direction of the signal lines.

[0018] One embodiment of the present invention is a module comprising any of the above-described display devices, wherein an IC is mounted by connecting a flexible printed circuit board (FPC) board or a cable tray package (TCP) or by a method such as chip-on-glass (COG) or chip-on-film (COF).

[0019] In one embodiment of the present invention, the above structure can also be applied to an input / output device (touch panel, etc.) but not to a display device.

[0020] One embodiment of the present invention is an electronic device including the above-described module and at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and operation buttons.

[0021] According to one embodiment of the present invention, a high-definition liquid crystal display device can be provided. According to other embodiments of the present invention, a liquid crystal display device with a high aperture ratio can be provided. According to other embodiments of the present invention, a liquid crystal display device with high contrast and display quality can be provided. According to other embodiments of the present invention, a liquid crystal display device capable of low-voltage driving can be provided. According to other embodiments of the present invention, a liquid crystal display device with low power consumption can be provided. According to other embodiments of the present invention, a liquid crystal display device with high reliability can be provided. According to other embodiments of the present invention, a novel liquid crystal display device can be provided.

[0022] Note that the description of the above effects does not exclude the existence of other effects. In one embodiment of the invention, it is not necessary to achieve all of the above effects. Effects other than those described above can be extracted from the description, drawings, claims, etc. Attached Figure Description

[0023] In the attached diagram:

[0024] Figures 1A to 1D This is a cross-sectional view showing an example of a liquid crystal element;

[0025] Figures 2A to 2C This is a top view showing the layout of the second common electrode;

[0026] Figure 3A This is a perspective view showing an example of a display device. Figure 3B and Figure 3C This is a top view showing an example of a sub-pixel;

[0027] Figure 4A and Figure 4B This is a cross-sectional view showing an example of a display device;

[0028] Figure 5A and Figure 5B This shows an example of pixel configuration and structure;

[0029] Figure 6 This is a cross-sectional view showing an example of a display device;

[0030] Figure 7 This is a cross-sectional view showing an example of a display device;

[0031] Figures 8A to 8D This is a cross-sectional view showing an example of a display device;

[0032] Figure 9A and Figure 9B This is a cross-sectional view showing an example of a display device;

[0033] Figure 10 This is a cross-sectional view showing an example of a display device;

[0034] Figure 11A and Figure 11B This is a perspective view showing an example of a touch panel;

[0035] Figure 12 This is a cross-sectional view showing an example of a touch panel;

[0036] Figure 13A and Figure 13B Examples of input devices and methods for driving input devices are shown;

[0037] Figure 14A and Figure 14B This is a perspective view showing an example of a touch panel;

[0038] Figure 15 This is a cross-sectional view showing an example of a touch panel;

[0039] Figure 16 This is a cross-sectional view showing an example of a touch panel;

[0040] Figures 17A to 17D This is a top view showing an example of an input device;

[0041] Figures 18A to 18E This is a top view showing an example of an input device;

[0042] Figure 19 This is a cross-sectional view showing an example of a touch panel;

[0043] Figure 20A and Figure 20B Examples of sensor elements and pixels are shown;

[0044] Figures 21A to 21E This shows a working example of sensor elements and pixels;

[0045] Figures 22A to 22C This is a top view showing examples of sensor elements and pixels;

[0046] Figure 23 This is a block diagram illustrating an example of a touch panel module;

[0047] Figures 24A to 24C An example of a touch panel module is shown;

[0048] Figure 25A1 , Figure 25A2 , Figure 25B1 , Figure 25B2 , Figure 25C1 and Figure 25C2 This is a cross-sectional view showing an example of a transistor;

[0049] Figures 26A1 to 26A3 , Figure 26B1 and Figure 26B2 This is a cross-sectional view showing an example of a transistor;

[0050] Figures 27A1 to 27A3 , Figure 27B1 , Figure 27B2 , Figure 27C1 and Figure 27C2 This is a cross-sectional view showing an example of a transistor;

[0051] Figures 28A to 28C These are top views and cross-sectional views illustrating an example of a transistor;

[0052] Figures 29A to 29C These are top views and cross-sectional views illustrating an example of a transistor;

[0053] Figures 30A to 30C These are top views and cross-sectional views illustrating an example of a transistor;

[0054] Figure 31A and Figure 31B These are top views and cross-sectional views illustrating an example of a transistor;

[0055] Figure 32A and Figure 32B These are top views and cross-sectional views illustrating an example of a transistor;

[0056] Figures 33A to 33C These are top views and cross-sectional views illustrating an example of a transistor;

[0057] Figures 34A to 34C These are top views and cross-sectional views illustrating an example of a transistor;

[0058] Figures 35A to 35CThese are top views and cross-sectional views illustrating an example of a transistor;

[0059] Figure 36 An example of a touch panel module is shown;

[0060] Figures 37A to 37H Examples of electronic devices are shown;

[0061] Figure 38A and Figure 38B Examples of electronic devices are shown;

[0062] Figure 39A and Figure 39B The pixel layout in Example 1 is shown;

[0063] Figure 40A and Figure 40B The orientation simulation results in Example 1 are shown;

[0064] Figure 41A and Figure 41B The orientation simulation results in Example 1 are shown;

[0065] Figure 42A and Figure 42B The orientation simulation results in Example 1 are shown;

[0066] Figure 43A and Figure 43B The orientation simulation results in Example 1 are shown;

[0067] Figure 44 The simulation results from Example 1 are shown;

[0068] Figure 45A This is a photograph showing the display result of the display device in Embodiment 1. Figure 45B and Figure 45C These are optical microscope photographs of the display section;

[0069] Figure 46A and Figure 46B The simulation results in Example 2 are shown; and

[0070] Figure 47A and Figure 47B The simulation results from Example 2 are shown. Detailed Implementation

[0071] The embodiments will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and those skilled in the art will readily understand that its methods and details can be varied in many ways without departing from the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited to the descriptions in the following embodiments.

[0072] Note that in the invention structure described below, the same reference numerals are used in different figures to denote the same parts or parts with the same function, and repeated descriptions of such parts are omitted. Furthermore, sometimes the same shading lines are used for parts with the same function without additional reference numerals.

[0073] For ease of understanding, the positions, dimensions, or extents of the structures shown in the accompanying drawings are sometimes not accurately represented. Therefore, the disclosed invention is not necessarily limited to the positions, dimensions, or extents disclosed in the accompanying drawings.

[0074] Note that the terms "film" and "layer" can be interchanged depending on the context or situation. For example, "conductive layer" can be replaced with "conductive film." Similarly, "insulating film" can be replaced with "insulating layer."

[0075] (Implementation Method 1)

[0076] In this embodiment, refer to Figures 1A to 24C A display device according to one embodiment of the present invention will be described.

[0077] A display device according to one embodiment of the present invention includes a pixel electrode, a first common electrode, a second common electrode, and a liquid crystal layer. The pixel electrode and the first common electrode are positioned opposite the second common electrode across the liquid crystal layer in the thickness direction of the display device. The first common electrode and the second common electrode are supplied with the same potential. The first common electrode includes a portion overlapping the second common electrode between the display areas of two adjacent sub-pixels displaying different colors. At least one of the pixel electrode and the first common electrode includes a portion in the display area of ​​a sub-pixel that does not overlap with the second common electrode.

[0078] The display device includes multiple pixels and has the function of displaying images.

[0079] A pixel comprises multiple subpixels. For example, a subpixel that displays red, a subpixel that displays green, and a subpixel that displays blue form a single pixel, thus enabling full-color display in a display unit. Note that the colors displayed by a subpixel are not limited to red, green, and blue. For example, subpixels that display white, yellow, magenta, or cyan can also be used in a pixel. Note that in this specification, etc., a subpixel is sometimes simply referred to as a pixel.

[0080] Examples of driving methods for liquid crystal display devices include: frame inversion driving, where the positive and negative electrodes are inverted frame by frame (i.e., signal polarity is inverted); gate line inversion driving, where the positive and negative electrodes are inverted row by row; source line inversion driving, where the positive and negative electrodes are inverted column by column; and dot line inversion driving, where the positive and negative electrodes are inverted row by row and column by column. By inverting the signal polarity through these driving methods, screen burn-in can be prevented. From a power consumption perspective, source line inversion driving is preferred.

[0081] As liquid crystal display (LCD) devices achieve higher resolution, the width (spacing) between pixels and between sub-pixels decreases. Therefore, for example, when the source line is inverted and driven in an LCD device using a horizontal electric field, a horizontal electric field is generated between adjacent sub-pixels, potentially leading to misalignment of the liquid crystal and light leakage into adjacent sub-pixels. Light leakage degrades the display quality. While covering areas prone to light leakage with a light-shielding layer can suppress this degradation, it may reduce the aperture ratio.

[0082] Therefore, in one embodiment of the present invention, a liquid crystal layer is sandwiched between a pair of electrodes (a first common electrode and a second common electrode) supplied with the same potential between the display areas of two sub-pixels that display different colors from each other. This prevents the generation of a horizontal electric field between two adjacent sub-pixels. As a result, misalignment of the liquid crystal can be prevented to reduce light leakage, thereby improving the contrast of the display device.

[0083] In one embodiment of the invention, at least one of the pixel electrode and the first common electrode includes a portion in the display area of ​​the sub-pixel that does not overlap with the second common electrode. As a result, even if the second common electrode is provided, the driving voltage of the liquid crystal element does not easily increase.

[0084] <1-1. Example 1 of the structure of a display device>

[0085] Figures 1A to 1D A cross-sectional view of a display device according to one embodiment of the present invention is shown.

[0086] Figure 1A The display device shown includes a substrate 119a, a substrate 119b, a pixel electrode 111a, a pixel electrode 111b, a first common electrode 112, a liquid crystal layer 113, a second common electrode 244, and an insulating layer 220.

[0087] Figure 1A The display device shown includes display areas 68a and 68b. Display areas 68a and 68b are display areas (i.e., openings in the subpixels) of subpixels that display different colors from each other.

[0088] Pixel electrodes 111a and 111b and a first common electrode 112 are located between the liquid crystal layer 113 and the substrate 119a. A second common electrode 244 is located between the liquid crystal layer 113 and the substrate 119b. The first common electrode 112 and the second common electrode 244 are supplied with the same potential.

[0089] exist Figure 1A In the display device shown, a first common electrode 112 is located on a substrate 119a, an insulating layer 220 is located on the first common electrode 112, and island-shaped pixel electrodes 111a and 111b are located on the insulating layer 220. Pixel electrodes are disposed in each sub-pixel. In the display area, the pixel electrodes have openings or gaps (also referred to as slits, etc.).

[0090] Figure 1B The display device shown is with Figure 1A The difference lies in the stacking order of the pixel electrode and the first common electrode.

[0091] exist Figure 1B In the display device shown, island-shaped pixel electrodes 111a and 111b are located on substrate 119a, insulating layer 220 is located on pixel electrodes 111a and 111b, and first common electrode 112 is located on insulating layer 220. In the display area, the first common electrode 112 has an opening or gap (also referred to as a slit, etc.).

[0092] In each of the display areas 68a and 68b, a voltage can be applied between the pixel electrode and the first common electrode 112 (see reference). Figure 1A and Figure 1B (See the arrow shown). On the other hand, between display areas 68a and 68b, the liquid crystal layer 113 is sandwiched between a first common electrode 112 and a second common electrode 244, both supplied with the same potential (constant potential, common potential). The common potential of the electrodes supplied to the substrate 119b side prevents the electric field from diffusing from the pixel electrodes to the electrodes of adjacent sub-pixels. Therefore, misalignment of the liquid crystal can be prevented to reduce light leakage, thereby improving the contrast of the display device.

[0093] exist Figure 1A In this configuration, the first common electrode 112 has a portion in each of the display areas 68a and 68b that does not overlap with the second common electrode 244. Figure 1B In the display area 68a, pixel electrode 111a has a portion that does not overlap with the second common electrode 244, and pixel electrode 111b has a portion that does not overlap with the second common electrode 244 in the display area 68b. Compared to the case where the second common electrode 244 is disposed entirely in the display area of ​​the sub-pixel, the rise in the driving voltage of the liquid crystal element can be suppressed when the second common electrode 244 is disposed only partially.

[0094] exist Figure 1A and Figure 1B In the diagram, L1 represents the length of the display area of ​​the sub-pixel without the second common electrode 244, and L2 represents the length of the second common electrode 244 spanning between two sub-pixels. Figure 1A In this context, the thickness of the liquid crystal layer 113 between the pixel electrode and the second common electrode 244 is represented by d. Figure 1B In this diagram, the thickness of the liquid crystal layer 113 between the first common electrode 112 and the second common electrode 244 is represented by d. The thickness d of the liquid crystal layer is the thickness of the liquid crystal layer 113 between the second common electrode 244 and the pixel electrode or the first common electrode 112 that is closer to the second common electrode 244 in the thickness direction of the liquid crystal layer 113. The thickness d of the liquid crystal layer can also be described as the cell gap or the shortest distance between the second common electrode 244 and one of the pixel electrode or the first common electrode 112.

[0095] Figures 2A to 2C An example of the layout of the second common electrode 244 is shown.

[0096] In the example shown here, a pixel is composed of three sub-pixels: a red sub-pixel (R), a green sub-pixel (G), and a blue sub-pixel (B). The area outside the display area 68 of the sub-pixel is represented by the non-display area 66.

[0097] Figure 2A An example of a second common electrode 244 having an opening is shown. The opening is located in at least a portion of the display area 68. The opening may also extend into the non-display area 66.

[0098] exist Figure 2A In this context, length L1 is equal to the width of the opening. In other words, length L1 is the length of the shorter side of the opening or the length of the opening in the direction of the arrangement of subpixels of different colors.

[0099] exist Figure 2A In this context, length L2 equals the spacing between openings. In other words, length L2 is the spacing between openings in the arrangement direction of subpixels that represent different colors.

[0100] Figure 2B An example is shown where multiple second common electrodes 244 are arranged in a stripe pattern. The arrangement direction of the second common electrodes 244 intersects the arrangement direction of the sub-pixels that are of the same color.

[0101] One of the second common electrodes 244 spans between two adjacent sub-pixels that are different colors. For example, the second common electrode 244a spans between a red sub-pixel (R) and a green sub-pixel (G).

[0102] exist Figure 2BIn this context, the length L1 is equal to the interval between two adjacent second common electrodes.

[0103] exist Figure 2B In this context, length L2 is equal to the width of the second common electrode. In other words, length L2 is the length of the short side of the second common electrode or the length of the second common electrode in the direction of the arrangement of sub-pixels of different colors, etc.

[0104] Note that you can Figure 2B The second common electrode 244 shown is considered a comb-shaped electrode. In this case, Figure 2B In the portion not shown, the second common electrodes 244a, 244b, and 244c are continuous with each other. Length L1 can be considered as the spacing between the comb teeth, and length L2 can be considered as the width of the comb teeth.

[0105] Figure 2C An example is shown where an opening in the second common electrode 244 spans between two adjacent sub-pixels that are the same color. The opening may also be located in display area 68 among multiple sub-pixels that are the same color.

[0106] Preferably, the second common electrode 244 is set large to give it low resistance. For example, with Figure 2B and Figure 2C Compared to the structure, in Figure 2A In the structure shown, the resistance of the second common electrode 244 can be reduced.

[0107] Below, on Figures 1A to 1D The second common electrode 244 in the middle has Figure 2A The layout shown will be explained. Figures 1A to 1D In this configuration, the second common electrode 244 has an opening in the display area 68. Figures 1B to 1D In the display area 68, the first common electrode 112 has an opening.

[0108] Figure 1C and Figure 1D and Figure 1B The difference lies in the shape of the second common electrode 244.

[0109] like Figure 1C As shown, the first common electrode 112 may also have a portion in each of the display areas 68a and 68b that does not overlap with the second common electrode 244.

[0110] exist Figure 1B In this configuration, the width of the opening of the first common electrode 112 is equal to the width of the opening of the second common electrode 244.

[0111] exist Figure 1CIn this process, the width of the opening of the second common electrode 244 is wider than the width of the opening of the first common electrode 112.

[0112] exist Figure 1D In this process, the width of the opening of the second common electrode 244 is narrower than the width of the opening of the first common electrode 112.

[0113] When viewed from a direction perpendicular to the thickness of the liquid crystal layer 113, the length from the end of the opening in the second common electrode 244 to the end of the opening in the first common electrode 112 is... Figure 1C L3 represents the middle, in Figure 1D L4 represents the middle.

[0114] When the second common electrode 244 is set large in the sub-pixel, the diffusion of the electric field from the pixel electrode to the electrodes of adjacent sub-pixels can be further suppressed. In other words, the shorter the length L1 or the longer the length L2, the less light leakage can be achieved. Furthermore, Figure 1C The shorter the length L3 shown, the less light leakage can be reduced, and Figure 1D The longer the length L4 shown, the less light leakage can be reduced.

[0115] When the second common electrode 244 is set small in the display area of ​​the sub-pixel, the rise in the driving voltage of the liquid crystal element caused by the second common electrode 244 can be suppressed. In other words, the longer the length L1 or the shorter the length L2, the more effectively the rise in the driving voltage of the liquid crystal element can be suppressed. Furthermore, Figure 1C The longer the length L3 shown, the better it can suppress the rise of the driving voltage of the liquid crystal element, and Figure 1D The shorter the length L4 shown, the better the rise in the driving voltage of the liquid crystal element can be suppressed.

[0116] A smaller thickness d of the liquid crystal layer increases the influence of the second common electrode 244 and suppresses the horizontal electric field generated between the two sub-pixels. By reducing the thickness d of the liquid crystal layer, the length L1 can be increased (and the length L2 shortened). This prevents light leakage and the rise of the driving voltage.

[0117] From the above perspective, when the thickness of the liquid crystal layer is represented by d, the length L1 is preferably d / 6 or more, and more preferably d / 2 or more.

[0118] When the thickness of the liquid crystal layer is represented by d, the length L2 is preferably d or more and 2.5d or less, more preferably 1.2d or more and 2.4d or less. The length L2 affects the contrast ratio of the display device. The length L1 affects the driving voltage of the display device. Therefore, in the manufacturing of the display device, it is preferable to prioritize determining the length L2 condition that affects the display quality.

[0119] The thickness d of the liquid crystal layer is preferably 1 μm or more and 3 μm or less, more preferably 1.5 μm or more and 3 μm or less.

[0120] According to one embodiment of the present invention, light leakage between adjacent sub-pixels can be prevented, thus reducing the spacing between sub-pixels. Therefore, the aperture ratio of the sub-pixels is increased, the sharpness of the display device is improved, the display quality of the display device is enhanced, and the rise in driving voltage is suppressed. Furthermore, by increasing the aperture ratio, the light extraction efficiency can be improved. This, in turn, reduces the power consumption of the display device.

[0121] <1-2. Example 2 of the structure of a display device>

[0122] Figure 3A and Figure 4A An example of a display device is shown. Figure 3A This is a 3D view of display device 100A. Figure 4A This is a cross-sectional view of display device 100A. For clarity, in Figure 3A The constituent elements such as the polarizer 130 are not shown in the diagram. Figure 3A In the image, substrate 61 is shown by a dashed line.

[0123] Display device 100A includes a display section 62 and a driving circuit section 64. FPC 72 and IC 73 are mounted on display device 100A.

[0124] The display unit 62 includes multiple pixels and has the function of displaying images.

[0125] The display device 100A may include one or both of a scan line driving circuit and a signal line driving circuit. The display device 100A may also not include either a scan line driving circuit or a signal line driving circuit. When the display device 100A includes a sensor such as a touch sensor, it may also include a sensor driving circuit. In this embodiment, a driving circuit section 64 is shown as an example including a scan line driving circuit. The scan line driving circuit has the function of outputting scan signals to the scan lines included in the display section 62.

[0126] In the display device 100A, IC73 is mounted on substrate 51 in a COG manner or the like. IC73 includes, for example, one or more of signal line driving circuits, scan line driving circuits, and sensor driving circuits.

[0127] The FPC72 is electrically connected to the display device 100A. Signals or power are supplied to the IC73 and drive circuit section 64 from the outside via the FPC72. Additionally, signals can be output from the IC73 to the outside via the FPC72.

[0128] The FPC72 can be fitted with ICs. For example, the FPC72 can be fitted with one or more ICs, including signal line driver circuits, scan line driver circuits, and sensor driver circuits.

[0129] Wiring 65 supplies signals and power to the display unit 62 and the driving circuit unit 64. These signals and power are input to wiring 65 from the outside or from IC 73 via FPC 72.

[0130] Figure 3B and Figure 3C This is a top view of the sub-pixels included in the display device 100A.

[0131] Figure 4A It is a cross-sectional view including the display unit 62, the driving circuit unit 64, and the wiring 65. Figure 4A Including along Figure 3B A cross-sectional view between the dashed lines X1 and X2. Figure 4A In subsequent cross-sectional views of the display device, the display unit 62 includes a display area 68 in a sub-pixel and a non-display area 66 surrounding the display area 68.

[0132] Figure 3B This is a top view taken from the side of the first common electrode 112, showing the stacked structure in the sub-pixel from the gate 223 to the first common electrode 112 (see reference). Figure 4A ).exist Figure 3B In the text, the display area 68 within the sub-pixel is described by a thick dashed line. Figure 3C yes Figure 3B A top view of the stacked structure excluding the first common electrode 112.

[0133] Display device 100A is an example of a transmissive liquid crystal display device that includes a liquid crystal element in the manner of a horizontal electric field.

[0134] like Figure 4A As shown, the display device 100A includes a substrate 51, a transistor 201, a transistor 206, a liquid crystal element 40, auxiliary wiring 139, alignment films 133a and 133b, a connector 204, an adhesive layer 141, a coloring layer 131, a light-shielding layer 132, a protective layer 121, a substrate 61, and a polarizer 130.

[0135] Liquid crystal element 40 is disposed in display area 68. Liquid crystal element 40 is an FFS (Fringe Field Switching) mode liquid crystal element.

[0136] The liquid crystal element 40 includes a pixel electrode 111, a first common electrode 112, a second common electrode 244, and a liquid crystal layer 113. The orientation of the liquid crystal layer 113 can be controlled by the electric field generated between the pixel electrode 111 and the first common electrode 112. The liquid crystal layer 113 is located between alignment films 133a and 133b.

[0137] In the connection portion 69, the second common electrode 244 is electrically connected to the conductive layer on one side of the substrate 51. Therefore, a potential can be supplied to the second common electrode 244 via the FPC 72. Since it eliminates the need to connect an FPC or the like on the substrate 61 side, and further simplifies the structure of the display device, this is preferred.

[0138] The connecting part 69 may also be part of the display part 62. Alternatively, the connecting part 69 may be located outside the display part 62, for example, it may be provided between the display part 62 and the drive circuit part 64.

[0139] The same potential can be supplied to the first common electrode 112 and the second common electrode 244. For example, when the first common electrode 112 and the conductive layer 284 are electrically connected to each other or are composed of a single film, the second common electrode 244 is electrically connected to the first common electrode 112.

[0140] Note that the second common electrode 244 does not necessarily have to be electrically connected to the first common electrode 112. When the first common electrode 112 and the second common electrode 244 are electrically connected to different power lines, the same potential can be supplied to both power lines.

[0141] In the connection portion 69, conductive layer 281 is connected to conductive layer 282, conductive layer 282 is connected to conductive layer 283, conductive layer 283 is connected to conductive layer 284, conductive layer 284 is connected to connector 243, and connector 243 is connected to the second common electrode 244. Conductive layers 281, 282, and 283 can be formed using the same materials and manufacturing processes as the transistor gate 223, transistor gate 221, and conductive layers 222a and 222b. Manufacturing the conductive layers in the connection portion 69 in this manner (i.e., using the same materials and processes as the conductive layers in the display portion 62 and drive circuit portion 64) does not increase the number of processes, which is therefore preferable.

[0142] As the connector 243, conductive particles can be used, for example. The conductive particles can be organic resin or silica particles coated with a metallic material. Nickel or gold is preferred as the metallic material because this reduces contact resistance. Using particles coated with layers of two or more metallic materials is also preferred; for example, particles coated with nickel and also coated with gold. As the connector 243, a material capable of elastic or plastic deformation is preferably used. Figure 4A As shown, conductive particles sometimes have a vertically flattened shape. When they have a flattened shape, the contact area between the connector 243 and the conductive layer electrically connected to the connector 243 can be increased, thereby reducing contact resistance and reducing problems such as poor connection.

[0143] The connector 243 is preferably arranged to be covered by the adhesive layer 141. For example, the connector 243 may also be dispersed in the adhesive layer 141 before it hardens.

[0144] exist Figure 4A In the middle, the pixel electrode 111 is electrically connected to the low resistance region 231b through the conductive layer 222b.

[0145] like Figure 4B As shown, pixel electrode 111 can also be directly connected to low-resistance region 231b. In this case, the semiconductor layer (channel region 231a and low-resistance region 231b) preferably contains a material that transmits visible light, such as oxide semiconductor. Therefore, the connection between pixel electrode 111 and transistor can be provided in display area 68, thereby improving the aperture ratio of sub-pixels and the clarity of the display device. Note that low-resistance region 231b can be electrically connected to conductive layer 222b. Conductive layer 222b can be used as an auxiliary electrode for low-resistance region 231b. Transistor does not necessarily have to include conductive layer 222b.

[0146] The first common electrode 112 may have a comb-shaped top surface (also known as a planar shape) or a top surface shape with slits. Figure 3B and Figure 3C and Figure 4A An example is shown where an opening is provided in the first common electrode 112 within the display area 68 of a sub-pixel. As display devices become increasingly high-resolution, the area of ​​the display area 68 within a sub-pixel decreases. Therefore, the number of openings provided in the first common electrode 112 is not limited to multiple; a single opening can also be provided. In other words, in high-resolution display devices, the area of ​​the pixel (sub-pixel) is small, so even if there is only one opening in the first common electrode 112, a sufficient electric field for liquid crystal alignment can be generated across the entire display area of ​​the sub-pixel.

[0147] An insulating layer 220 is provided between the pixel electrode 111 and the first common electrode 112. The pixel electrode 111 includes a portion that overlaps with the first common electrode 112 across the insulating layer 220. Furthermore, in some regions where the pixel electrode 111 overlaps with the color layer 131, the first common electrode 112 is not provided on the pixel electrode 111. An auxiliary wiring 139 is provided on the first common electrode 112. The resistance of the auxiliary wiring 139 is preferably lower than the resistance of the first common electrode 112. By providing auxiliary wiring electrically connected to the common electrode, voltage drops caused by the resistance of the common electrode can be suppressed. Additionally, when using a stacked structure of a conductive layer containing a metal oxide and a conductive layer containing a metal, it is preferable to form these conductive layers using a patterning technique employing a halftone mask, thereby simplifying the manufacturing process.

[0148] The auxiliary wiring 139 is a film with a lower resistance than the first common electrode 112. For example, the auxiliary wiring 139 can be formed in a single-layer or multi-layer structure using any of the following metal materials: molybdenum, titanium, chromium, tantalum, tungsten, aluminum, copper, silver, neodymium, scandium, and alloy materials containing the above elements.

[0149] The auxiliary wiring 139 is preferably positioned at a location that overlaps with the light-shielding layer 132, so that the auxiliary wiring 139 is not visible to the user of the display device.

[0150] The alignment film is preferably disposed in contact with the liquid crystal layer 113. The alignment film can control the alignment of the liquid crystal layer 113. In the display device 100A, the alignment film 133a is located between the first common electrode 112 (or insulating layer 220) and the liquid crystal layer 113, and the alignment film 133b is located between the second common electrode 244 (or protective layer 121) and the liquid crystal layer 113.

[0151] Liquid crystal materials are classified into positive liquid crystal materials with positive dielectric anisotropy (Δε) and negative liquid crystal materials with negative dielectric anisotropy. In one embodiment of the present invention, both materials can be used, and an appropriate liquid crystal material can be selected according to the mode and design adopted.

[0152] In one embodiment of the present invention, a negative liquid crystal material is preferably used. Negative liquid crystal materials are less susceptible to the flexural effect caused by the polarization of liquid crystal molecules; therefore, the polarity of the voltage applied to the liquid crystal layer has almost no effect on transmittance. Thus, flicker can be suppressed for users of the display device. The flexural effect refers to a phenomenon primarily caused by molecular shape and polarization due to orientation distortion. Negative liquid crystal materials are less prone to deformation such as bending and twisting.

[0153] Note that the liquid crystal element 40 here is an element using FFS mode; however, one embodiment of the present invention is not limited to this, and liquid crystal elements using various modes can be used. For example, liquid crystal elements using VA (Vertical Alignment), TN (Twisted Nematic), IPS (In-Plane-Switching), ASM (Axially Symmetric Aligned Micro-cell), OCB (Optically Compensated Birefringence), FLC (Ferroelectric Liquid Crystal), AFLC (Antiferroelectric Liquid Crystal), etc., can be used.

[0154] Alternatively, the display device 100A can also be a normally black liquid crystal display device, such as a transmissive liquid crystal display device in vertical alignment (VA) mode. Examples of vertical alignment modes include MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode, and ASV (Advanced Super View) mode.

[0155] Liquid crystal elements (LCDs) are devices that utilize the optical modulation properties of liquid crystals to control the transmission and non-transmission of light. The optical modulation property of liquid crystals is controlled by the electric field (including horizontal, vertical, and tilting electric fields) applied to them. Liquid crystals used in LCD elements can be thermotropic liquid crystals, low-molecular-weight liquid crystals, high-molecular-weight liquid crystals, polymer-dispersed liquid crystals (PDLCs), ferroelectric liquid crystals, and antiferroelectric liquid crystals. These liquid crystal materials exhibit cholesteric, smectic, cubic, chiral, and isotropic phases depending on the conditions.

[0156] When using a horizontal electric field, a blue-phase liquid crystal can be used without an alignment film. The blue phase is one of the liquid crystal phases, referring to the phase that appears just before the cholesteric liquid crystal transitions to a homogeneous phase when the temperature is raised. Because the blue phase only appears within a narrow temperature range, a liquid crystal composition containing at least 5 wt% chiral reagent is used in the liquid crystal layer 113 to improve the temperature range. Liquid crystal compositions containing both the blue-phase liquid crystal and the chiral reagent have a fast response speed and exhibit optical isotropy, making alignment processing unnecessary. Furthermore, liquid crystal compositions containing both the blue-phase liquid crystal and the chiral reagent have low viewing angle dependence. Additionally, since no alignment film is required and friction processing is unnecessary, electrostatic damage caused by friction processing can be prevented, and defects or breakage of the liquid crystal display device during the manufacturing process can be reduced.

[0157] Since the display device 100A is a transmissive liquid crystal display device, a conductive material that transmits visible light is used for both the pixel electrode 111 and the first common electrode 112. When the second common electrode 244 is located in the display area 68, the conductive material that transmits visible light is also used for the second common electrode 244.

[0158] As a conductive material that transmits visible light, materials containing one or more of indium (In), zinc (Zn), and tin (Sn) are preferably used. Specifically, examples include indium oxide, indium tin oxide (ITO), indium zinc oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium tin oxide containing silicon oxide (ITSO), zinc oxide, and zinc oxide containing gallium. Note that films containing graphene can also be used. Graphene-containing films can be formed, for example, by reducing a film containing graphene oxide.

[0159] Preferably, at least one of the pixel electrode 111 and the first common electrode 112 comprises an oxide conductive layer. The oxide conductive layer preferably comprises one or more metal elements found in the semiconductor layers of the transistor 206. For example, the pixel electrode 111 preferably comprises indium, more preferably an In-M-Zn oxide film (M is Al, Ti, Ga, Ge, Y, Zr, La, Ce, Nd, Sn, or Hf). Similarly, the first common electrode 112 preferably comprises indium, more preferably an In-M-Zn oxide film.

[0160] At least one of the pixel electrode 111 and the first common electrode 112 can also be formed using an oxide semiconductor. When two or more layers constituting the display device are formed using an oxide semiconductor containing the same metal element, the manufacturing apparatus (e.g., a film deposition apparatus or a processing apparatus, etc.) can be used in two or more processes, thus reducing manufacturing costs.

[0161] Oxide semiconductors are semiconductor materials whose resistance can be controlled by the concentration of oxygen vacancies and / or impurities such as hydrogen or water in the semiconductor film. Therefore, by selectively increasing or decreasing the concentration of oxygen vacancies and / or impurities in the oxide semiconductor layer, the resistivity of the oxide conductive layer can be controlled.

[0162] Note that the oxide conductive layer formed using the oxide semiconductor layer described above can also be referred to as an oxide semiconductor layer with high carrier density and low resistance, an oxide semiconductor layer with conductivity, or an oxide semiconductor layer with high conductivity.

[0163] Furthermore, manufacturing costs can be reduced by using the same metal elements to form both the oxide semiconductor layer and the oxide conductive layer. For example, using metal oxide targets with the same metal composition can reduce manufacturing costs. By using metal oxide targets with the same metal composition, the etching gases or etchants used in the processing of the oxide semiconductor layer can be used for the processing of the oxide conductive layer. Note that even if the oxide semiconductor layer and the oxide conductive layer have the same metal elements, sometimes the composition of the metal elements may differ. For example, in the manufacturing process of display devices, sometimes metal elements in the film may detach, causing a change in the metal composition.

[0164] For example, when a silicon nitride film containing hydrogen is used for the insulating layer 220 and an oxide semiconductor is used for the pixel electrode 111, the conductivity of the oxide semiconductor can be improved due to the hydrogen supplied from the insulating layer 220.

[0165] Transistor 206 is provided in the non-display area 66.

[0166] Transistor 206 includes a gate 221, a gate 223, an insulating layer 211, an insulating layer 213, and a semiconductor layer (channel region 231a and a pair of low-resistance regions 231b). The resistance of the low-resistance region 231b is lower than the resistance of the channel region 231a. In this embodiment, as an example, an oxide semiconductor layer is used as the semiconductor layer. The oxide semiconductor layer preferably contains indium, and more preferably is an In-M-Zn oxide film (M is Al, Ti, Ga, Ge, Y, Zr, La, Ce, Nd, Sn, or Hf). Details of the oxide semiconductor layer will be described later.

[0167] Gate 221 is superimposed on channel region 231a through insulating layer 213. Gate 223 is superimposed on channel region 231a through insulating layer 211. Insulating layers 211 and 213 serve as gate insulating layers. Through openings provided in insulating layers 212 and 214, conductive layer 222a is connected to one of low-resistance regions 231b, and conductive layer 222b is connected to the other of low-resistance regions 231b.

[0168] Figure 4A The transistor 206 shown is a transistor with gates disposed above and below the channel.

[0169] exist Figure 3C In the contact portion Q1 shown, gate 221 and gate 223 are electrically connected. Compared to other transistors, a transistor with two electrically connected gates can have a high field-effect mobility, thereby achieving a high on-state current. Therefore, a circuit capable of high-speed operation can be obtained. Furthermore, the footprint of the circuit section can be reduced. By using a transistor with high on-state current, even in display devices where the number of wirings increases due to larger size or higher resolution, signal delay of wiring can be reduced, and display non-uniformity can be suppressed. Additionally, by employing this structure, highly reliable transistors can be manufactured.

[0170] exist Figure 3C In the contact portion Q2 shown, the conductive layer 222b is connected to the pixel electrode 111.

[0171] In other words, in Figure 3B and Figure 3C In this configuration, a conductive layer is used as both the scan line 228 and the gate 223. Preferably, the gate 221 and gate 223, which have low resistance, are also used as the conductive layer for the scan line.

[0172] In other words, in Figure 3B and Figure 3C In this configuration, a conductive layer is used as signal line 229 and conductive layer 222a.

[0173] Both gate 221 and gate 223 can comprise a single layer of one of a metal material and an oxide conductor, or a stack of both a metal material and an oxide conductor. For example, one of gate 221 and gate 223 can also comprise an oxide conductor, and the other of gate 221 and gate 223 can also comprise a metal material.

[0174] Transistor 206 can be formed to include an oxide semiconductor layer as the semiconductor layer and an oxide conductive layer as at least one of gate 221 and gate 223. In this case, it is preferable to use oxide semiconductor for both the oxide semiconductor layer and the oxide conductive layer.

[0175] When a conductive layer that blocks visible light is used for the gate 223, light from the backlight source can be suppressed from entering the channel region 231a, thereby further improving the reliability of the transistor.

[0176] Transistor 206 is covered by insulating layers 212, 214, 215, and 216. Note that insulating layers 212, 214, and 216 can also be considered as constituent elements of transistor 206. The transistor is preferably covered by insulating layers that reduce impurity diffusion in the semiconductor constituting the transistor. Insulating layer 215 can be used as a planarization layer.

[0177] Both insulating layers 211 and 213 preferably include excess oxygen regions. When the gate insulating layer includes excess oxygen regions, excess oxygen can be supplied to the channel region 231a. Because excess oxygen can fill oxygen vacancies that may form in the channel region 231a, a highly reliable transistor can be provided.

[0178] The insulating layer 212 preferably contains nitrogen or hydrogen. When the insulating layer 212 comes into contact with the low-resistance region 231b, the nitrogen or hydrogen in the insulating layer 212 is added to the low-resistance region 231b. When nitrogen or hydrogen is added to the low-resistance region 231b, the carrier density of the low-resistance region 231b becomes higher. Furthermore, when the insulating layer 214 contains nitrogen or hydrogen and the insulating layer 212 allows nitrogen or hydrogen to permeate, nitrogen or hydrogen can also be added to the low-resistance region 231b.

[0179] In display device 100A, a coloring layer 131 and a light-shielding layer 132 are disposed closer to the substrate 61 than the liquid crystal layer 113. The coloring layer 131 is located in a region that overlaps at least with the display area 68 of a sub-pixel. The light-shielding layer 132 is disposed 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.

[0180] Preferably, a protective layer 121 is provided between the coloring layer 131 or the light-shielding layer 132 and the liquid crystal layer 113. The protective layer 121 can suppress the diffusion of impurities contained in the coloring layer 131 and the light-shielding layer 132 into the liquid crystal layer 113. Figure 4A In this process, a second common electrode 244 is provided between the protective layer 121 and the alignment film 133b.

[0181] The substrate 51 and the substrate 61 are bonded together using an adhesive layer 141. A liquid crystal layer 113 is sealed in the area surrounded by the substrate 51, the substrate 61 and the adhesive layer 141.

[0182] When the display device 100A is used as a transmissive liquid crystal display device, two polarizers are arranged to sandwich the display unit 62. Figure 4AA polarizer 130 is shown on one side of the substrate 61. Light 45 from a backlight source located outside the polarizer on one side of the substrate 51 enters the display device 100A after passing through the polarizer. At this time, the orientation of the liquid crystal layer 113 can be controlled by the voltage applied between the pixel electrode 111 and the first common electrode 112, thereby controlling the optical modulation of the light. That is, the intensity of the light emitted after passing through the polarizer 130 can be controlled. In addition, the color layer 131 absorbs light of wavelengths outside the specified wavelength range of the incident light. Therefore, the emitted light may appear red, blue, or green, for example.

[0183] Besides polarizers, circular polarizers can also be used, for example. Examples of circular polarizers include those formed by stacking linear polarizers and quarter-wave phase détravisors. Using circular polarizers can reduce the viewing angle dependence of display quality in a display device.

[0184] The drive circuit section 64 includes transistor 201.

[0185] Transistor 201 includes a gate 221, a gate 223, an insulating layer 211, an insulating layer 213, a semiconductor layer (channel region 231a and a pair of low-resistance regions 231b), a conductive layer 222a, and a conductive layer 222b. One of the conductive layers 222a and 222b is used as the source, and the other is used as the drain. Conductive layer 222a is electrically connected to one of the low-resistance regions 231b, and conductive layer 222b is connected to the other low-resistance region 231b.

[0186] In the connection portion 204, the wiring 65 is connected to the conductive layer 251, and the conductive layer 251 is connected to the connector 242. In other words, in the connection portion 204, the wiring 65 is electrically connected to the FPC 72 through the conductive layer 251 and the connector 242. By adopting the above structure, signals and power can be supplied from the FPC 72 to the wiring 65.

[0187] Wiring 65 can be formed using the same material and the same manufacturing process as the conductive layers 222a and 222b included in transistor 206. Conductive layer 251 can be formed using the same material and the same manufacturing process as the pixel electrode 111 included in liquid crystal element 40. By manufacturing the conductive layer constituting the connection portion 204 in the above manner (i.e., using the same material and the same manufacturing process as the conductive layer constituting the display portion 62 and the driving circuit portion 64), the number of processes is not increased, which is therefore preferred.

[0188] Transistors 201 and 206 may have the same structure or different structures. That is, the transistors included in the driving circuit section 64 and the transistors included in the display section 62 may have the same structure or different structures. Furthermore, the driving circuit section 64 may include multiple transistors with different structures, and the display section 62 may include multiple transistors with different structures. For example, it is preferable to use a transistor with two gates electrically connected to each other for one or more of the shift register circuit, buffer circuit, and protection circuit included in the scan line driving circuit.

[0189] Figure 5A and Figure 5B This shows an example of pixel configuration. Figure 5A and Figure 5B This illustrates an example where a pixel is composed of a red sub-pixel R, a green sub-pixel G, and a blue sub-pixel B. Figure 5A and Figure 5B In the diagram, multiple scan lines 81 extend in the x-direction, and multiple signal lines 82 extend in the y-direction. The scan lines 81 and signal lines 82 intersect.

[0190] like Figure 5A As shown by the double-dotted line, the sub-pixel includes a transistor 206, a capacitor 34, and a liquid crystal element 40. The gate of transistor 206 is electrically connected to scan line 81. One of the source and drain of transistor 206 is electrically connected to signal line 82, and the other is electrically connected to one electrode of capacitor 34 and one electrode of liquid crystal element 40. The other electrode of capacitor 34 and the other electrode of liquid crystal element 40 are both supplied with a constant potential.

[0191] Figure 5A and Figure 5B This illustrates an example using source line inversion drive. Signals A1 and A2 have the same polarity. Signals B1 and B2 have the same polarity. Signals A1 and B1 have different polarities. Signals A2 and B2 have different polarities.

[0192] As display devices become increasingly high-resolution, the spacing between sub-pixels becomes narrower. Therefore, as... Figure 5A As shown in the dashed box, in the subpixel receiving input signal A1, near signal line 82 of input signal B1, the liquid crystal is easily affected by the potentials of both signals A1 and B1. This can easily lead to misalignment of the liquid crystal.

[0193] exist Figure 5A In this context, multiple sub-pixels displaying the same color are arranged in the y-direction, roughly parallel to the extension direction of signal line 82. For example... Figure 5A As shown in the dotted-line box, when subpixels are facing each other on their long sides, subpixels of different colors are adjacent.

[0194] exist Figure 5B In the image, multiple sub-pixels of the same color are arranged in the x-direction, intersecting the extension direction of signal line 82. For example... Figure 5B As shown in the dashed box, subpixels of the same color are adjacent when their short sides are opposite each other.

[0195] like Figure 5B As shown, when one side of the sub-pixel that is approximately parallel to the extension direction of signal line 82 is the short side of the sub-pixel, the case where the long side of the sub-pixel is approximately parallel to the extension direction of signal line 82 (see reference). Figure 5A Compared to [previous method], this allows for a narrower area where misalignment of liquid crystals is prone to occur. For example... Figure 5B As shown, when a region prone to misalignment of liquid crystals is located between subpixels displaying the same color, the situation differs from when that region is located between subpixels displaying different colors (see reference). Figure 5A Compared to other display devices, users of the display device are less likely to notice display defects. In one embodiment of the invention, the arrangement direction of the plurality of sub-pixels displaying the same color is preferably intersecting the extension direction of the signal line 82.

[0196] In a display device according to one embodiment of the present invention, the second common electrode 244 helps to prevent misalignment of the liquid crystal. Therefore, one embodiment of the present invention can employ... Figure 5A The structure shown is formed by the arrangement of multiple sub-pixels of different colors intersecting the extension direction of signal line 82.

[0197] Figure 6 A cross-sectional view of the display device 100B is shown. Note that the perspective view of the display device 100B is different from that of the display device 100B. Figure 3A The display device shown is the same as 100A, so the description is omitted.

[0198] Display device 100A shows an example where the transistor includes two gates. In display device 100B, transistors 201 and 206 each include only a gate 221. Additionally, display device 100B includes a spacer 117. Detailed descriptions of the same components in display device 100B as those in display device 100A are omitted.

[0199] Transistors 201 and 206 are disposed on insulating layer 211. Insulating layer 211 serves as a base film. Transistor 206 includes a gate 221, insulating layer 213, and a semiconductor layer (channel region 231a and a pair of low-resistance regions 231b). Through openings in insulating layers 212 and 214, conductive layer 222a is connected to one of the low-resistance regions 231b, and conductive layer 222b is connected to the other of the low-resistance regions 231b. Insulating layer 215 serves as a planarization layer.

[0200] In the connection portion 69, conductive layer 281 is connected to conductive layer 282, conductive layer 282 is connected to conductive layer 283, conductive layer 283 is connected to connector 243, and connector 243 is connected to the second common electrode 244. Conductive layers 281 and 282 can be formed using the same materials and manufacturing processes as the gate 221, conductive layers 222a, and conductive layers 222b, respectively. Manufacturing the conductive layers in the connection portion 69 in this manner (i.e., using the same materials and processes as the conductive layers in the display portion 62 and the driving circuit portion 64) does not increase the number of processes, which is therefore preferable.

[0201] The spacer 117 has the function of maintaining a certain distance between the substrate 51 and the substrate 61.

[0202] exist Figure 6 In the example shown, the bottom surface of the spacer 117 is in contact with the protective layer 121, but one embodiment of the invention is not limited to this. The spacer 117 may be disposed on one side of the substrate 51 or on one side of the substrate 61.

[0203] exist Figure 6 In the example shown, alignment films 133a and 133b do not contact each other in the region where they overlap with spacer 117, although they may also contact each other. Furthermore, spacer 117 disposed on one substrate may or may not contact a structure disposed on another substrate. For example, liquid crystal layer 113 may also be located between spacer 117 and the structure.

[0204] Particulate spacers can also be used as spacers 117. Materials such as silica can be used as particulate spacers. The spacers are preferably made of elastic materials such as resin or rubber. In this case, the particulate spacers sometimes have a vertically flattened shape.

[0205] Next, detailed descriptions of the materials, etc., of each component of the display device that can be used in this embodiment will be provided. Note that descriptions of components that have already been described may sometimes be omitted. Furthermore, the following materials may also be appropriately used in the display device, touch panel, and their components shown later.

[0206] Substrate 51, 61

[0207] There are no particular limitations on the material of the substrate used in the display device according to one embodiment of the present invention, and various substrates can be used. For example, glass substrates, quartz substrates, sapphire substrates, semiconductor substrates, ceramic substrates, metal substrates, or plastic substrates can be used.

[0208] By using a thin substrate, the weight and thickness of the display device can be reduced. Furthermore, by using a substrate whose thickness allows for flexibility, a flexible display device can be obtained.

[0209] One embodiment of the present invention discloses a display device manufactured by forming transistors or the like on a manufacturing substrate and then transferring the transistors or the like onto another substrate. By using a manufacturing substrate, transistors with good characteristics can be formed, transistors with low power consumption can be formed, display devices that are not easily damaged can be manufactured, display devices can be given heat resistance, lightweight display devices can be manufactured, and thin display devices can be manufactured. Examples of substrates for transferring transistors include, in addition to substrates capable of forming transistors, paper substrates, cellophane substrates, stone substrates, wood substrates, cloth substrates (including natural fibers (silk, cotton, hemp), synthetic fibers (nylon, polyurethane, polyester), recycled fibers (acetate fiber, cuprammonium fiber, synthetic fiber, recycled polyester), leather substrates, and rubber substrates.

[0210] Transistors 201 and 206

[0211] The display device according to one embodiment of the present invention includes transistors that can have either a top-gate or a bottom-gate structure. Gate electrodes can be disposed above and below the channel. There are no particular limitations on the semiconductor material used for the transistors; for example, oxide semiconductors, silicon, germanium, etc., can be used.

[0212] There are no particular restrictions on the crystallinity of the semiconductor material used in transistors; amorphous semiconductors or crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors with a portion of crystalline regions) can be used. Crystalline semiconductors are preferred because they can suppress transistor performance degradation.

[0213] For example, Group 14 elements, compound semiconductors, or oxide semiconductors can be used as semiconductor layers. Typically, semiconductors containing silicon, semiconductors containing gallium arsenide, or oxide semiconductors containing indium can be used as semiconductor layers.

[0214] Oxide semiconductors are preferably used for forming the channels of transistors. In particular, oxide semiconductors with a larger band gap than silicon are preferred. By using a semiconductor material with a wider band gap and lower carrier density compared to silicon, the off-state current of the transistor can be reduced, which is why it is preferred.

[0215] The oxide semiconductor preferably contains at least indium (In) or zinc (Zn). More preferably, the oxide semiconductor contains In-M-Zn oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, La, Ce, Nd, Sn or Hf).

[0216] As a semiconductor layer, an oxide semiconductor layer having a plurality of crystal portions having a c-axis oriented in a direction substantially perpendicular to the surface of the semiconductor layer or the top surface of the semiconductor layer, and having no grain boundaries between adjacent crystal portions is particularly preferred.

[0217] By using this oxide semiconductor as a semiconductor layer, highly reliable transistors with reduced variations in electrical characteristics can be provided.

[0218] Because the transistors described above have low off-state current, they can retain the charge stored in the capacitor for extended periods. By using such transistors in pixels, it is possible to stop the driving circuit while maintaining the grayscale of the displayed image. As a result, a display device with extremely low power consumption can be obtained.

[0219] Transistors 201 and 206 preferably include an oxide semiconductor layer that has been highly purified to suppress the formation of oxygen vacancies. This reduces the off-state current of the transistor. Consequently, electrical signals such as image signals can be maintained for longer periods, and the write interval can be extended in the on-state. Therefore, the refresh frequency can be reduced, thereby suppressing power consumption.

[0220] High field-effect mobility can be achieved in transistors 201 and 206, enabling high-speed driving. By using such high-speed driven transistors in a display device, both the display transistors and the driving circuit transistors can be fabricated on the same substrate. This means that since a separate semiconductor device formed from silicon wafers or the like is not required for the driving circuit, the number of components in the display device can be reduced. Furthermore, by using high-speed driven transistors in the display section, high-quality images can also be provided.

[0221] Oxide Semiconductor Layer

[0222] The oxide semiconductor layer preferably comprises a film represented as In-M-Zn oxide containing at least indium (In), zinc (Zn), and M (metals such as Al, Ti, Ga, Ge, Y, Zr, La, Ce, Nd, Sn, or Hf). To reduce electrical characteristic inhomogeneities in transistors containing this oxide semiconductor, the oxide semiconductor preferably contains not only the In-M-Zn oxide but also a stabilizer.

[0223] Stabilizers include metals that can be used as M, such as gallium (Ga), tin (Sn), hafnium (Hf), aluminum (Al), and zirconium (Zr). Other lanthanide elements such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), or lutetium (Lu) can be used as stabilizers.

[0224] The oxide semiconductor included as the oxide semiconductor layer can be, for example, In-Ga oxide, In-Zn oxide, In-Ga-Zn oxide, In-Al-Zn oxide, In-Sn-Zn oxide, In-Hf-Zn oxide, In-La-Zn oxide, In-Ce-Zn oxide, In-Pr-Zn oxide, In-Nd-Zn oxide, In-Sm-Zn oxide, In-Eu-Zn oxide, and In-Gd-Zn oxide. In-Tb-Zn oxides, In-Dy-Zn oxides, In-Ho-Zn oxides, In-Er-Zn oxides, In-Tm-Zn oxides, In-Yb-Zn oxides, In-Lu-Zn ​​oxides, In-Sn-Ga-Zn oxides, In-Hf-Ga-Zn oxides, In-Al-Ga-Zn oxides, In-Sn-Al-Zn oxides, In-Sn-Hf-Zn oxides, and In-Hf-Al-Zn oxides.

[0225] Note that, for example, "In-Ga-Zn oxides" here refers to oxides with In, Ga, and Zn as their main components, and there is no restriction on the proportion of In, Ga, and Zn. Furthermore, it may also contain metallic elements other than In, Ga, and Zn.

[0226] Note that when the oxide semiconductor layer contains In-M-Zn oxide, assuming the sum of In and M is 100 atomic%, it is preferred that the atomic percentage of In is greater than 25 atomic% and the atomic percentage of M is less than 75 atomic%, and more preferably that the atomic percentage of In is greater than 34 atomic% and the atomic percentage of M is less than 66 atomic%.

[0227] The bandgap of the oxide semiconductor layer is 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more. By using an oxide semiconductor with such a wide bandgap, the off-state current of the transistor can be reduced.

[0228] The thickness of the oxide semiconductor layer is 3 nm or more and 200 nm or less, preferably 3 nm or more and 100 nm or less, and more preferably 3 nm or more and 50 nm or less.

[0229] When the oxide semiconductor layer comprises In-M-Zn oxide (M is Al, Ti, Ga, Ge, Y, Zr, La, Ce, Nd, Sn, or Hf), it is preferable that the atomic ratio of the metal elements in the sputtering target used to form the In-M-Zn oxide film satisfies In ≥ M and Zn ≥ M. Examples of such atomic ratios for the metal elements in the sputtering target include In:M:Zn = 1:1:1, In:M:Zn = 1:1:1.2, In:M:Zn = 3:1:2, In:M:Zn = 1:3:4, and In:M:Zn = 1:3:6. Note that the atomic ratio of the metal elements in the formed oxide semiconductor layer deviates from the aforementioned atomic ratio of the metal elements in the sputtering target within an error range of ±40%.

[0230] As an oxide semiconductor layer, an oxide semiconductor layer with a low carrier density can be used. For example, as an oxide semiconductor layer, a carrier density of 1×10⁻⁶ can be used. 17 / cm 3 The following is preferred: 1×10 15 / cm 3 Hereinafter, 1×10 is more preferred. 13 / cm 3 Hereinafter, 1×10 is further preferred. 11 / cm 3 The following are oxide semiconductor layers with the following carrier density.

[0231] Note that, not limited to the above description, materials with appropriate compositions can be used according to the semiconductor and electrical properties (field-effect mobility, threshold voltage, etc.) of the required transistor.

[0232] When the oxide semiconductor layer contains silicon or carbon, one of the Group 14 elements, the number of oxygen vacancies in the oxide semiconductor layer increases, and the oxide semiconductor layer becomes n-type. Therefore, the concentration of silicon or carbon in the oxide semiconductor layer (measured by SIMS) is 2 × 10⁻⁶. 18 atoms / cm 3 The following is preferred: 2×10 17 atoms / cm 3 the following.

[0233] In addition, the concentration of alkali metals or alkaline earth metals in the oxide semiconductor layer, as measured by SIMS, is 1 × 10¹ 8 atoms / cm 3 The following is preferred: 2×10 16 atoms / cm 3The following applies. Sometimes, when alkali metals and alkaline earth metals bond with oxide semiconductors, charge carriers are generated, increasing the off-state current of the transistor. Therefore, it is preferable to reduce the concentration of alkali metals or alkaline earth metals in the oxide semiconductor layer.

[0234] When an oxide semiconductor layer contains nitrogen, electrons are generated as charge carriers, increasing the charge carrier density and making the oxide semiconductor layer more prone to n-type configuration. As a result, transistors containing nitrogen-containing oxide semiconductors tend to become always-on. Therefore, it is preferable to minimize nitrogen in this oxide semiconductor layer; for example, the nitrogen concentration measured using SIMS is preferably set to 5 × 10⁻⁶. 18 atoms / cm 3 the following.

[0235] Oxide semiconductor layers can also have non-single-crystal structures. Non-single-crystal structures include, for example, CAAC-OS (CAxis Aligned Crystalline Oxide Semiconductor), polycrystalline structures, microcrystalline structures, or amorphous structures. Among non-single-crystal structures, amorphous structures have the highest defect state density, while CAAC-OS has the lowest.

[0236] Oxide semiconductor layers can also have an amorphous structure, for example. An amorphous oxide semiconductor layer has, for example, a disordered atomic arrangement and no crystalline components. Alternatively, an amorphous oxide film can be, for example, a completely amorphous structure and have no crystalline portions.

[0237] Note that the oxide semiconductor layer can also be a hybrid film having two or more of the following regions: amorphous, microcrystalline, polycrystalline, CAAC-OS, and single-crystal. Hybrid films sometimes have, for example, two or more monolayer structures including regions of amorphous, microcrystalline, polycrystalline, CAAC-OS, and single-crystal. Additionally, hybrid films sometimes have, for example, two or more stacked structures including regions of amorphous, microcrystalline, polycrystalline, CAAC-OS, and single-crystal.

[0238] Insulation Layer

[0239] As insulating materials that can be used in various insulating layers, protective layers, spacers, etc., included in a display device, both organic and inorganic insulating materials can be used. Examples of organic insulating materials include acrylic resins, epoxy resins, polyimide resins, polyamide resins, polyamide-imide resins, siloxane resins, benzocyclobutene resins, and phenolic resins. Examples of inorganic insulating films include silicon oxide films, silicon oxynitride films, silicon oxynitride films, silicon nitride films, aluminum oxide films, hafnium oxide films, yttrium oxide films, zirconium oxide films, gallium oxide films, tantalum oxide films, magnesium oxide films, lanthanum oxide films, cerium oxide films, and neodymium oxide films.

[0240] Conductive Layer

[0241] As conductive layers for the gate, source, and drain of transistors, as well as wiring and electrodes in display devices, single-layer or multi-layer structures of metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, or alloys with these metals as the main components, can be used. Examples include: a two-layer structure with a titanium film stacked on an aluminum film; a two-layer structure with a titanium film stacked on a tungsten film; a two-layer structure with a copper film stacked on a molybdenum film; a two-layer structure with a copper film stacked on an alloy film containing molybdenum and tungsten; a two-layer structure with a copper film stacked on a copper-magnesium-aluminum alloy film; a three-layer structure consisting of sequentially stacked titanium or titanium nitride films; a three-layer structure consisting of sequentially stacked molybdenum or molybdenum nitride films; and a three-layer structure consisting of sequentially stacked molybdenum or molybdenum nitride films. For example, when the conductive layer has a three-layer structure, it is preferable that each of the first and third layers is preferably a film formed of titanium, titanium nitride, molybdenum, tungsten, an alloy containing molybdenum and tungsten, an alloy containing molybdenum and zirconium, or molybdenum nitride, and the second layer is preferably a film formed of a low-resistance material such as copper, aluminum, gold, silver, or an alloy containing copper and manganese. Note that transparent conductive materials such as ITO, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, and ITSO can also be used.

[0242] An oxide conductive layer can be formed by controlling the resistivity of oxide semiconductors.

[0243] Adhesive Layer 141

[0244] As the adhesive layer 141, a thermosetting resin, a UV-curing resin, a two-component curing resin, or other curing resin can be used. For example, acrylic resin, polyurethane resin, epoxy resin, or silicone resin can be used.

[0245] Connector 242

[0246] As connectors 242 and 243, for example, anisotropic conductive film (ACF) or anisotropic conductive paste (ACP) can be used.

[0247] Coloring Layer 131

[0248] Colored layer 131 is a colored layer that allows light within a specified wavelength range to pass through. Examples of materials that can be used for colored layer 131 include metallic materials, resin materials, and resin materials containing pigments or dyes.

[0249] Light-blocking layer 132

[0250] For example, the light-shielding layer 132 is disposed between adjacent coloring layers 131 of different colors. For example, a black matrix formed using a metallic material or a resin material containing pigments or dyes can be used as the light-shielding layer 132. Note that by disposing the light-shielding layer 132 in an area outside the display section 62, such as the drive circuit section 64, unintentional light leakage, such as waveguide light, can be suppressed, which is therefore preferable.

[0251] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting display devices can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), and atomic layer deposition (ALD). Examples of CVD methods include plasma-enhanced chemical vapor deposition (PECVD) and thermal CVD. An example of a thermal CVD method is metal-organic chemical vapor deposition (MOCVD).

[0252] Alternatively, the thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed using methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife coating, slot coating, roller coating, curtain coating, and doctor knife coating.

[0253] Thin films constituting display devices can be processed using methods such as photolithography. Additionally, island-shaped thin films can be formed using film deposition methods employing masking masks. Furthermore, thin films can be processed using nanoimprint lithography, sandblasting, and lift-off methods. Examples of photolithography include methods such as forming a resist mask on the thin film to be processed, processing the thin film by etching or the like, and then removing the resist mask; and forming a photosensitive thin film and processing it into a desired shape by exposure and development.

[0254] In photolithography, examples of light used for exposure include i-line light (wavelength 365 nm), g-line light (wavelength 436 nm), h-line light (wavelength 405 nm), and light composed of a mixture of i-line, g-line, and h-line light. Additionally, ultraviolet light, KrF lasers, or ArF lasers can also be used. Immersion exposure techniques can be employed. Examples of light used for exposure include extreme ultraviolet (EUV) light or X-rays. Electron beams can be used instead of the light used for exposure. Extremely fine processing can be achieved using EUV light, X-rays, or electron beams, making them preferred methods. Note that when exposure is performed by scanning with an electron beam, a photomask is not required.

[0255] As a method for etching thin films, dry etching, wet etching, or sandblasting can be used.

[0256] <1-3. Structural Example 3 of a Display Device>

[0257] Figures 7 to 10 An example of a display device is shown. Figure 7 This is a cross-sectional view of the display device 100C. Figure 8A This is a cross-sectional view of the display device 100D. Figure 9A This is a cross-sectional view of the display device 100E. Figure 10 This is a cross-sectional view of display device 100F. Note that the perspective views of display devices 100C, 100D, 100E, and 100F are different from those of display devices 100F. Figure 3A The perspective view of the display device 100A shown is the same, so it will not be described here.

[0258] Figure 7 The difference between the display device 100C shown and the display device 100A described above is the position of the pixel electrode 111 and the first common electrode 112.

[0259] exist Figure 4A In the display device 100A shown, the alignment film 133a is in contact with the first common electrode 112. On the other hand, in Figure 7In the display device 100C shown, the alignment film 133a is in contact with the pixel electrode 111.

[0260] Figures 8A to 8D The display device 100D shown differs from the display device 100A in the shape of the pixel electrode 111 and the first common electrode 112.

[0261] Both the pixel electrode 111 and the first common electrode 112 can have a comb-shaped top surface (also known as a planar shape) or a top surface shape with slits.

[0262] exist Figures 8A to 8D In the display device 100D shown, the pixel electrode 111 and the first common electrode 112 are disposed on the same plane.

[0263] In addition, the electrodes may have a shape in which the end of a slit in one electrode is aligned with the end of a slit in another electrode. Figure 8B The cross-sectional view at this point is shown.

[0264] Furthermore, viewed from the top, the pixel electrode 111 and the first common electrode 112 may also have overlapping portions. Figure 8C The cross-sectional view at this point is shown.

[0265] Furthermore, viewed from the top, the display unit 62 may also have a portion where neither the pixel electrode 111 nor the first common electrode 112 is disposed. Figure 8D The cross-sectional view at this point is shown.

[0266] Figure 9A The display device 100E shown and Figure 10 The difference between each of the display devices 100F shown and the display device 100A lies in the shape of the transistors.

[0267] exist Figure 9A In the transistor, transistors 201 and 206 each include a gate 221, an insulating layer 213, a conductive layer 222a, a conductive layer 222b, and a semiconductor layer 231.

[0268] Gate 221 overlaps with semiconductor layer 231 via insulating layer 213. Insulating layer 213 serves as gate insulating layer. Conductive layers 222a and 222b each have portions connected to semiconductor layer 231. One of conductive layers 222a and 222b serves as source electrode, and the other as drain electrode. Transistors 201 and 206 are covered by insulating layers 212 and 214.

[0269] exist Figure 9A In this configuration, pixel electrode 111 is connected to conductive layer 222b. Additionally, as... Figure 9BAs shown, the pixel electrode 111 can be connected to the semiconductor layer 231. In this case, the semiconductor layer 231 is preferably made of a material that transmits visible light, such as an oxide semiconductor. This allows the connection between the pixel electrode 111 and the transistor to be provided in the display area 68, thereby improving the aperture ratio of the sub-pixels and the clarity of the display device. Note that the semiconductor layer 231 can be electrically connected to the conductive layer 222b. The conductive layer 222b can be used as an auxiliary electrode of the semiconductor layer 231. The transistor does not necessarily need to include the conductive layer 222b.

[0270] exist Figure 10 In the transistor, each of transistors 201 and 206 includes a gate 221, a gate 223, an insulating layer 212, an insulating layer 213, an insulating layer 214, a conductive layer 222a, a conductive layer 222b, and a semiconductor layer 231.

[0271] Gate 221 overlaps with semiconductor layer 231 via insulating layer 213. Gate 223 overlaps with semiconductor layer 231 via insulating layers 212 and 214. Insulating layers 212 to 214 are all used as gate insulating layers. Conductive layers 222a and 222b each include a portion connected to semiconductor layer 231. One of conductive layers 222a and 222b is used as a source electrode, and the other is used as a drain electrode. Transistors 201 and 206 are covered by insulating layer 215. Conductive layer 222b is connected to pixel electrode 111.

[0272] As described above, a display device according to one embodiment of the present invention may include transistors and liquid crystal elements of various shapes.

[0273] <1-4. Structural Example 4 of a Display Device>

[0274] One embodiment of the present invention can be used in a display device equipped with a touch sensor, which is also referred to as an input / output device or a touch panel. The structures of the aforementioned display devices can be used in touch panels. In this embodiment, an example of mounting a touch sensor in a display device 100A will be mainly described.

[0275] There are no limitations on the sensing elements (also referred to as sensor elements) included in the touch panel of one embodiment of the present invention. Various sensors capable of sensing the proximity or contact of objects such as fingers or styluses can be used as sensor elements.

[0276] For example, various methods can be used as sensors, such as capacitive, resistive, surface acoustic wave, infrared, optical, and pressure-sensitive sensors.

[0277] In this embodiment, a touch panel including a capacitive sensor element will be used as an example for explanation.

[0278] Examples of capacitive touch sensor elements include surface-type capacitive touch sensor elements and projection-type capacitive touch sensor elements. Examples of projection-type capacitive touch sensor elements include self-capacitance touch sensor elements and mutual-capacitance touch sensor elements. When using a mutual-capacitance touch sensor element, multi-point sensing can be performed simultaneously, so it is preferred.

[0279] The touch panel of one embodiment of the present invention can adopt various structures: a structure in which a display device and a sensor element are bonded together, a structure in which electrodes including the sensor element are provided on one or both of the substrate supporting the display element and the opposing substrate.

[0280] Figure 11A and Figure 11B as well as Figure 12 An example of a touch panel is shown. Figure 11A This is a 3D model of the 350A touch panel. Figure 11B yes Figure 11A The unfolded diagram of the 3D schematic diagram. Note that, for clarity, Figure 11A and Figure 11B Only the main components are shown. Figure 11B In the image, substrates 61 and 162 are shown only in outline using dashed lines. Figure 12 This is a cross-sectional view of the 350A touch panel.

[0281] The touch panel 350A has a structure that integrates separately manufactured display devices and sensor elements.

[0282] The touch panel 350A includes an input device 375 and a display device 370 arranged in an overlapping manner.

[0283] The input device 375 includes a substrate 162, electrodes 127 and 128, a plurality of wirings 137 and a plurality of wirings 138. The FPC 72b is electrically connected to each of the plurality of wirings 137 and 138. An IC 73b is disposed on the FPC 72b.

[0284] The display device 370 includes substrates 51 and 61 arranged opposite to each other. The display device 370 includes a display section 62 and a driving circuit section 64. Wiring 65 and the like are provided on substrate 51. FPC 72a is electrically connected to wiring 65. IC 73a is provided on FPC 72a.

[0285] Wiring 65 supplies signals and power to the display unit 62 and the drive circuit unit 64. These signals and power are input to wiring 65 from the outside or from IC 73a via FPC 72a.

[0286] Figure 12This is a cross-sectional view of the display unit 62, the driving circuit unit 64, the area including FPC72a, and the area including FPC72b.

[0287] Substrate 51 and substrate 61 are bonded together by adhesive layer 141. Substrate 61 and substrate 162 are bonded together by adhesive layer 169. Here, each layer from substrate 51 to substrate 61 corresponds to display device 370. Each layer from substrate 162 to electrode 124 corresponds to input device 375. That is, adhesive layer 169 bonds display device 370 and input device 375 together.

[0288] Figure 12 The structure of the display device 370 shown is similar to Figure 4A The display device shown is the same as 100A, and detailed descriptions are omitted here.

[0289] Polarizer 165 is attached to substrate 51 using adhesive layer 167. Backlight 161 is attached to polarizer 165 using adhesive layer 163.

[0290] Polarizer 166 is attached to substrate 162 using adhesive layer 168. Protective substrate 160 is attached to polarizer 166 using adhesive layer 164. When touch panel 350A is installed in electronic device, protective substrate 160 can also be used as a substrate that is in direct contact with objects such as fingers or styluses. As protective substrate 160, substrates that can be used as substrate 51 and substrate 61, etc. are acceptable. Preferably, a structure in which a protective layer is formed on the surface of a substrate that can be used as substrate 51 and substrate 61, etc., is used to protect substrate 160. Alternatively, tempered glass or the like is preferable as protective substrate 160. This protective layer can be formed using a ceramic coating. This protective layer can be formed using inorganic insulating materials such as silicon oxide, aluminum oxide, yttrium oxide, yttrium oxide-stabilized zirconium oxide (YSZ).

[0291] A polarizer 166 can be disposed between the input device 375 and the display device 370. In this case, it is not necessary to set it. Figure 12 The protective substrate 160, adhesive layer 164, and adhesive layer 168 are shown. That is, the substrate 162 can be located on the outermost side of the touch panel 350A. As the substrate 162, the material described above that can be used to protect the substrate 160 is preferably used.

[0292] Electrodes 127 and 128 are disposed on the surface of substrate 162 opposite to substrate 61. Electrodes 127 and 128 are formed on the same plane. An insulating layer 125 is disposed to cover electrodes 127 and 128. Electrode 124 is electrically connected to the two electrodes 128 disposed on both sides of electrode 127 through an opening provided in the insulating layer 125.

[0293] In the conductive layer included in the input device 375, the conductive layer (electrodes 127, 128, etc.) that overlaps with the display area 68 is formed using a material that allows visible light to pass through.

[0294] Wiring 137, obtained by processing the same conductive layer as electrodes 127 and 128, is connected to conductive layer 126, obtained by processing the same conductive layer as electrode 124. Conductive layer 126 is electrically connected to FPC 72b via connector 242b.

[0295] Next, refer to Figure 13A and Figure 13B An example of a driving method for an input device (touch sensor) of a display device that can be used in one embodiment of the present invention will be described.

[0296] Figure 13A This is a block diagram showing the structure of a mutual capacitance touch sensor. Figure 13A The pulse voltage output circuit 601 and the current sensing circuit 602 are shown. Figure 13A In this example, six wirings X1 to X6 represent electrodes 621 to which pulses are applied, and six wirings Y1 to Y6 represent electrodes 622 to which changes in current are sensed. The number of such electrodes is not limited to this example. Figure 13A A capacitor 603 is also shown, formed by overlapping electrodes 621 and 622 or by arranging electrodes 621 and 622 in close proximity. Note that the functions of electrodes 621 and 622 can be interchanged.

[0297] For example, electrode 127 corresponds to one of electrode 621 or electrode 622, and electrode 128 corresponds to the other of electrode 621 or electrode 622.

[0298] The pulse voltage output circuit 601 is, for example, a circuit that sequentially inputs pulse voltages to wirings X1 to X6. The current sensing circuit 602 is, for example, a circuit that senses the current flowing through each wiring Y1 to Y6.

[0299] When a pulse voltage is applied to one of the wirings X1 to X6, an electric field is generated between electrodes 621 and 622 of capacitor 603, causing current to flow through electrode 622. A portion of the electric field generated between the electrodes is blocked when an object such as a finger or stylus approaches or touches the device, thereby changing the strength of the electric field between the electrodes. As a result, the amount of current flowing through electrode 622 changes.

[0300] For example, when no object is near or in contact with the conductor, the amount of current flowing through each of the wirings Y1 to Y6 depends on the capacitance of capacitor 603. When a portion of the electric field is blocked due to the proximity or contact of an object, a decrease in the amount of current flowing through wirings Y1 to Y6 is sensed. This change can be used to detect the proximity or contact of an object.

[0301] The current sensing circuit 602 can also sense the integral value (time integral value) of the current flowing through the wiring. In this case, for example, an integrator circuit can be used. Alternatively, the peak value of the current can be sensed. In this case, for example, the current can be converted into a voltage and the peak value of the voltage can be sensed.

[0302] Figure 13B It is shown Figure 13A The example shown is a timing diagram of the input and output waveforms in a mutual capacitance touch sensor. Figure 13B In the process, sensing is performed on each row and each column during the first sensing period. Figure 13B The diagram shows the periods during which no object is detected approaching or touching (when the touch sensor is not touched) and the periods during which an object is detected approaching or touching (when the touch sensor is touched). Here, wiring Y1 to Y6 each show the voltage waveform corresponding to the sensed current.

[0303] like Figure 13B As shown, pulse voltages are supplied sequentially to wirings X1 to X6. Therefore, current flows through wirings Y1 to Y6. When the touch sensor is not touched, approximately the same current flows through wirings Y1 to Y6 according to the voltage changes in wirings X1 to X6, thus wirings Y1 to Y6 have the same output waveform. On the other hand, when the touch sensor is touched, the current flowing through the wirings at the locations in wirings Y1 to Y6 where the object is in contact or near decreases, so... Figure 13B As shown, the output waveform changes.

[0304] Figure 13B Examples are shown where an object comes into contact with or is near the intersection of wiring X3 and wiring Y3 or in the vicinity of it.

[0305] Mutual capacitance touch sensors sense changes in current caused by the obstruction of the electric field generated between a pair of electrodes. This allows them to obtain the position information of an object. When the sensing sensitivity is high, the coordinates of the object can be detected even if it is far from the detection surface (e.g., the surface of a touch panel).

[0306] By driving the touch panel in a way that the display period of the display unit and the sensing period of the touch sensor do not overlap, the detection sensitivity of the touch sensor can be improved. For example, the display period and the sensing period can be set separately within a single display frame. In this case, it is preferable to set two or more sensing periods within one frame. Increasing the sensing frequency can further improve the detection sensitivity.

[0307] The pulse voltage output circuit 601 and the current sensing circuit 602 are preferably formed in a single IC. This IC is preferably mounted on a substrate within the housing of the touch panel or electronic device. When the touch panel is flexible, the parasitic capacitance of the curved portion of the touch panel may increase, potentially amplifying the impact of noise. From this perspective, it is preferable to use an IC employing a driving method that is less susceptible to noise. For example, it is preferable to use an IC employing a driving method that improves the signal-to-noise ratio (S / N ratio).

[0308] <1-5. Structural Example 5 of a Display Device>

[0309] Figures 14A to 14B and Figure 15 An example of a touch panel is shown. Figure 14A This is a 3D view of the 350B touch panel. Figure 14B yes Figure 14A The unfolded diagram of the 3D schematic diagram. Note that, for clarity, Figure 14A and Figure 14B Only the main components are shown. Figure 14B In the image, substrate 61 is shown only by dashed lines, indicating its outline. Figure 15 This is a cross-sectional view of the 350B touch panel.

[0310] The 350B touch panel is an In-Cell type touch panel that has the function of displaying images and is used as a touch sensor.

[0311] The touch panel 350B has a structure in which electrodes constituting sensor elements are provided only on an opposing substrate. By adopting this structure, compared with a structure in which the display device and sensor elements are manufactured separately and bonded together, the touch panel can be made thinner and lighter, or the number of components in the touch panel can be reduced.

[0312] exist Figure 14A and Figure 14B In this embodiment, the input device 376 is disposed on the substrate 61. In addition, the wiring 137 and wiring 138 of the input device 376 are electrically connected to the FPC 72 included in the display device 379.

[0313] By adopting the above structure, the FPC connected to the touch panel 350B can be disposed on only one side of the substrate (in this embodiment, on the substrate 51 side). Although two or more FPCs can also be bonded to the touch panel 350B, from the viewpoint of structural simplification, as... Figure 14A and Figure 14B As shown, it is preferable to provide an FPC72 for the touch panel 350B, which has the function of supplying signals to both the display device 379 and the input device 376.

[0314] IC73 can function as a driver for input device 376. Another IC driving input device 376 can be mounted on FPC72. Alternatively, the IC driving input device 376 can also be mounted on substrate 51.

[0315] Figure 15 It includes a region, which includes Figure 14A The diagram shown includes the area of ​​FPC72, the connection part 63, the drive circuit part 64, and the display part 62.

[0316] In the connection portion 63, a wiring 137 (or wiring 138) is electrically connected to one of the conductive layers disposed on one side of the substrate 51 via a connector 243.

[0317] A light-shielding layer 132 is provided in contact with the substrate 61, thereby preventing the conductive layer used in the touch sensor from being seen by the user. The light-shielding layer 132 is covered by an insulating layer 122. An electrode 127 is provided between the insulating layers 122 and 125. An electrode 128 is provided between the insulating layers 125 and 123. Electrodes 127 and 128 can be formed of metal or alloy. A coloring layer 131 is provided in contact with the insulating layer 123. Note that, as Figure 16 As shown, in addition to the light-shielding layer 132b that contacts the substrate 61, a light-shielding layer 132a that contacts the insulating layer 123 may also be provided.

[0318] Wiring 137, obtained by processing the same conductive layer as electrode 127, is connected to conductive layer 285, obtained by processing the same conductive layer as electrode 128. Conductive layer 285 is connected to conductive layer 286, obtained by processing the same conductive layer as the second common electrode 244. Conductive layer 286 is electrically connected to conductive layer 284 via connector 243.

[0319] The touch panel 350B is supplied with signals from an FPC to drive the pixels and signals to drive the sensor elements. This allows the touch panel 350B to be easily installed in electronic devices and reduces the number of components.

[0320] <1-6. Examples of Touch Sensor Structures>

[0321] Below, we will describe a structural example of an input device (touch sensor).

[0322] Figure 17A A top view of the input device 415 is shown. The input device 415 includes a plurality of electrodes 471, a plurality of electrodes 472, a plurality of wirings 476, and a plurality of wirings 477 on a substrate 416. The substrate 416 is provided with an FPC 450 electrically connected to each of the plurality of wirings 476 and the plurality of wirings 477. Figure 17A This shows an example of an FPC450 with an IC449.

[0323] Figure 17B yes Figure 17A An enlarged view of the area enclosed by the dotted line. Electrode 471 has a shape in which columns of diamond-shaped electrode patterns are arranged in the transverse direction. The columns of diamond-shaped electrode patterns are electrically connected to each other. Electrode 472 also has a shape in which columns of diamond-shaped electrode patterns are arranged in the longitudinal direction, and the columns of diamond-shaped electrode patterns are electrically connected to each other. Electrodes 471 and 472 partially overlap and intersect each other. At the intersection, an insulator is sandwiched between electrodes 471 and 472 to prevent short circuits between these electrodes.

[0324] like Figure 17C As shown, electrode 472 can also have multiple island-shaped rhomboid electrodes 473 and bridging electrodes 474. The island-shaped rhomboid electrodes 473 are arranged in the longitudinal direction, and adjacent electrodes 473 are electrically connected to each other through bridging electrodes 474. By adopting the above structure, electrodes 473 and 471 can be formed in one step by processing the same conductive film. This suppresses thickness variations in these electrodes, and suppresses variations in resistance and light transmittance of each electrode due to their different locations. Note that although electrode 472 has bridging electrodes 474 here, electrode 471 can also have this structure.

[0325] like Figure 17D As shown, it is also possible to use... Figure 17B The diamond-shaped electrode patterns of electrodes 471 and 472 shown are cut out on the inside, leaving only the ends. In this case, when the width of electrodes 471 and 472 is so narrow that their thickness is not visible to the user, as described later, electrodes 471 and 472 can also be formed using light-shielding materials such as metal or alloy. Additionally, Figure 17D The electrode 471 or electrode 472 shown may also include the aforementioned bridging electrode 474.

[0326] One of electrodes 471 is electrically connected to one of wiring 476. One of electrodes 472 is electrically connected to one of wiring 477. Here, one of electrodes 471 and 472 corresponds to a row wiring and the other corresponds to a column wiring.

[0327] IC449 functions to drive a touch sensor. The signal output from IC449 is supplied to electrode 471 or electrode 472 via wiring 476 or 477. The current (or potential) flowing through electrode 471 or electrode 472 is input to IC449 via wiring 476 or 477. In this example, IC449 is mounted on FPC450, but it can also be mounted on substrate 416.

[0328] When the input device 415 overlaps with the display surface of the display panel, it is preferable to use a light-transmitting conductive material as electrodes 471 and 472. When a light-transmitting conductive material is used as electrodes 471 and 472 and light from the display panel is extracted through electrodes 471 or 472, it is preferable to arrange a conductive film containing the same conductive material as a dummy pattern between electrodes 471 and 472. By filling a portion of the gap between electrodes 471 and 472 with a dummy pattern, deviations in light transmittance can be reduced. As a result, brightness deviations of the light transmitted through the input device 415 can be reduced.

[0329] As a transparent and conductive material, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and gallium-containing zinc oxide can be used. Note that graphene-containing films can also be used. Graphene-containing films can be formed, for example, by reducing a film containing graphene oxide. As a reduction method, heating methods can be employed.

[0330] Alternatively, a metal or alloy film thinned to a thickness that allows light to pass through can be used. For example, metals such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or alloys containing such metals, can be used. Alternatively, nitrides of the metal or alloy (e.g., titanium nitride) can also be used. Furthermore, two or more laminated conductive films containing the aforementioned materials can be used.

[0331] Electrodes 471 and 472 can also be made of conductive films processed to a degree so fine that they are invisible to the user. For example, by processing such conductive films into a grid pattern (mesh pattern), both high conductivity and high visibility of the display device can be achieved. Preferably, the conductive film has a width of 30 nm or more and 100 μm or less, more preferably 50 nm or more and 50 μm or less, and more preferably 50 nm or more and 20 μm or less. In particular, conductive films with a pattern width of 10 μm or less are difficult for the user to see, and are therefore preferred.

[0332] exist Figures 18A to 18D As an example, the following is shown Figure 17B The diagram shows an enlarged view of region 460.

[0333] Figure 18A An example is shown using a grid-like conductive film 461. It is preferable that the conductive film 461 is arranged so as not to overlap with the display elements included in the display device, thus preventing light from the display elements from being blocked. In this case, it is preferable that the orientation of the grid is consistent with the orientation of the arrangement of the display elements, and that the spacing of the grid is an integer multiple of the spacing of the arrangement of the display elements.

[0334] Figure 18BAn example is shown of a lattice-shaped conductive film 462 processed in a manner forming triangular openings. By employing the above structure, with Figure 18A Compared to the structure shown, the resistance can be further reduced.

[0335] Or, such as Figure 18C As shown, a conductive film 463 with a non-periodic pattern shape can also be used. By adopting the above structure, moire patterns generated when overlapping with the display section of the display device can be suppressed.

[0336] Conductive nanowires can also be used as electrodes 471 and 472. Figure 18D An example of using nanowires 464 is shown. By dispersing nanowires 464 at an appropriate density to contact adjacent nanowires, a two-dimensional network can be formed, thereby allowing nanowires 464 to be used as a conductive film with extremely high light transmittance. For example, nanowires with an average diameter of 1 nm or more and 100 nm or less, preferably 5 nm or more and 50 nm or less, and more preferably 5 nm or more and 25 nm or less can be used. Metal nanowires such as Ag nanowires, Cu nanowires, and Al nanowires, or carbon nanotubes, can be used as nanowires 464. When using Ag nanowires, a light transmittance of 89% or more and a thin film resistance of 40 Ω / □ or more and 100 Ω / □ or less can be achieved.

[0337] Figure 18E Show Figure 17B More detailed structural examples of electrodes 471 and 472 are shown. Figure 18E This is an example of using a lattice-shaped conductive film for each of electrodes 471 and 472.

[0338] Although Figure 17A The example shown above illustrates the top surface shape of electrodes 471 and 472, where multiple rhombuses are arranged in one direction. However, the shapes of electrodes 471 and 472 are not limited to this; various top surface shapes, such as strips (rectangular shapes), curved strips, or serrated shapes, can also be used. Furthermore, while the above description shows an arrangement where electrodes 471 and 472 are orthogonal, this is not mandatory; the angle between the two electrodes can be less than 90 degrees.

[0339] <1-7. Structural Examples of Display Devices 6>

[0340] Figure 19 An example of a touch panel is shown. Figure 19 This is a cross-sectional view of the 350D touch panel.

[0341] The 350D touch panel is an In-Cell type touch panel that has the function of displaying images and is used as a touch sensor.

[0342] The touch panel 350D has a structure in which electrodes constituting sensor elements are disposed only on the substrate supporting the display elements. By adopting this structure, compared with a structure in which the display device and sensor elements are manufactured separately and bonded together, or a structure in which the sensor elements are manufactured on one side of the opposing substrate, the touch panel can be made thinner and lighter, or the number of components in the touch panel can be reduced.

[0343] Figure 19 The touch panel 350D shown differs from the display device 100A described above in the layout of the common electrode and auxiliary wiring 139.

[0344] Multiple auxiliary wirings 139 are electrically connected to the first common electrode 112a or the first common electrode 112b.

[0345] Figure 19 The touch panel 350D shown can sense the proximity or contact of an object by utilizing the capacitance formed between the first common electrode 112a and the first common electrode 112b. In other words, in the touch panel 350D, the first common electrodes 112a and 112b serve as both the common electrode of the liquid crystal element and the electrode of the sensor element.

[0346] Thus, in a touch panel according to one embodiment of the present invention, the electrodes of the liquid crystal element also serve as electrodes of the sensor element, thereby simplifying the manufacturing process and reducing manufacturing costs. Furthermore, it enables the touch panel to be thinner and lighter.

[0347] The common electrode is electrically connected to the auxiliary wiring 139. By setting up the auxiliary wiring 139, the resistance of the sensor element's electrodes can be reduced. Because the resistance of the sensor element's electrodes is reduced, the time constant of the sensor element's electrodes can be reduced. The smaller the time constant of the sensor element's electrodes, the higher the detection sensitivity and the higher the detection accuracy.

[0348] For example, the time constant of the electrodes of the sensor element is greater than 0 seconds and 1×10 -4 Less than 1 second, preferably greater than 0 seconds and 5×10 -5 Less than 0 seconds, more preferably greater than 0 seconds and 5×10 -6 For seconds or less, a further preference is given to values ​​greater than 0 seconds and 5×10. -7 For seconds less than 0 seconds, a further preference is given to greater than 0 seconds and 2×10 -7 Less than a second. Especially when the time constant is set to 1×10. -6 When the time is less than a second, high detection sensitivity can be achieved while suppressing the influence of noise.

[0349] The touch panel 350D is supplied with signals from an FPC to drive the pixels and signals to drive the sensor elements. This allows the touch panel 350D to be easily installed in electronic devices and reduces the number of components.

[0350] Below are examples of how the touch panel 350D works.

[0351] Figure 20A It is an equivalent circuit diagram of a part of the pixel circuit in the display section 62 of the touch panel 350D.

[0352] Each pixel (sub-pixel) includes at least a transistor 206 and a liquid crystal element 40. The gate of transistor 206 is electrically connected to wiring 3501. One of the source and drain of transistor 206 is electrically connected to wiring 3502.

[0353] The pixel circuit includes multiple wirings extending in the X direction (e.g., wiring 3510_1, wiring 3510_2) and multiple wirings extending in the Y direction (e.g., wiring 3511_1). The aforementioned wirings are arranged in a manner that intersects each other and form a capacitor therebetween.

[0354] In a pixel circuit, the electrodes of liquid crystal elements in adjacent pixels are electrically connected to each other to form a block. This block is of two types: island-shaped blocks (e.g., blocks 3515_1, blocks 3515_2) and line-shaped blocks extending in the X or Y direction (e.g., block 3516 extending in the Y direction). Note that although... Figure 20A Only a portion of the pixel circuitry is shown, but in reality, these two types of blocks are repeatedly arranged in the X and Y directions. One electrode of the liquid crystal element is, for example, a common electrode. The other electrode of the liquid crystal element is, for example, a pixel electrode.

[0355] The wiring 3510_1 (or wiring 3510_2) extending in the X direction is electrically connected to the island block 3515_1 (or block 3515_2). Although not shown, the wiring 3510_1 extending in the X direction electrically connects multiple island blocks 3515_1 arranged discontinuously along the X direction via the linear blocks. Additionally, the wiring 3511_1 extending in the Y direction is electrically connected to the linear block 3516.

[0356] Figure 20BThis is an equivalent circuit diagram showing the connection relationship of multiple wirings (wirings 3510_1 to 3510_6, collectively referred to as wiring 3510) extending in the X direction and multiple wirings (wirings 3511_1 to 3511_6, collectively referred to as wiring 3511) extending in the Y direction. A common potential can be input to each of the wirings 3510 extending in the X direction and each of the wirings 3511 extending in the Y direction. A pulse voltage can be input from a pulse voltage output circuit to each of the wirings 3510 extending in the X direction. Furthermore, each of the wirings 3511 extending in the Y direction can be electrically connected to a detection circuit. Note that wirings 3510 and 3511 can also be interchanged.

[0357] Below, refer to Figure 21A and Figure 21B An example illustrating how the touch panel 350D works is provided.

[0358] Here, a frame period is divided into a write period and a sensing period. The write period is the period during which image data is written to the pixels, and wiring 3501 (also known as gate lines or scan lines) is selected sequentially. The sensing period is the period during which sensing is performed using sensor elements.

[0359] Figure 21A This is the equivalent circuit diagram during the write operation. During the write operation, both the wiring 3510 extending in the X direction and the wiring 3511 extending in the Y direction are input to a common potential.

[0360] Figure 21B This is the equivalent circuit diagram during the sensing period. During the sensing period, each wiring 3511 extending in the Y direction is electrically connected to the detection circuit. Additionally, the wiring 3510 extending in the X direction is input with a pulse voltage from the pulse voltage output circuit.

[0361] Figure 21C This is an example of a timing diagram of the input and output waveforms of a mutual capacitance sensor element.

[0362] exist Figure 21C In this process, objects in each row and column are sensed within a single frame. Figure 21C The diagram illustrates two scenarios during the sensing process: when no object is detected (not touched) and when an object is detected (touched).

[0363] A pulse voltage is supplied from the pulse voltage output circuit to wirings 3510_1 to 3510_6. When a pulse voltage is applied to wirings 3510_1 to 3510_6, an electric field is generated between a pair of electrodes forming a capacitor, causing current to flow through the capacitor. This electric field generated between the electrodes changes due to touch, such as being blocked by a finger or stylus. That is, the capacitance value of the capacitor changes due to touch, etc. By utilizing this situation, the proximity or contact of an object can be sensed.

[0364] Wiring 3511_1 to 3511_6 is connected to a detection circuit for detecting current changes in wiring 3511_1 to 3511_6 caused by changes in the capacitance of the capacitor. The detected current value in wiring 3511_1 to 3511_6 does not change when no object is near or in contact with it, but decreases when the capacitance decreases due to the proximity or contact of an object. To detect current changes, the sum of current quantities can be detected. In this case, an integrating circuit or the like can be used to detect the sum of current quantities. Alternatively, the peak value of the current can be detected. In this case, the current can be converted into a voltage and the peak value of the voltage can be detected.

[0365] Note that in Figure 21C In the diagram, the waveforms of wirings 3511_1 to 3511_6 show the voltage values ​​corresponding to the detected current values. For example... Figure 21C As shown, it is preferable to synchronize the timing of the display operation with the timing of the sensing operation.

[0366] The waveforms of wires 3511_1 to 3511_6 change according to the pulse voltage applied to wires 3510_1 to 3510_6. When no object is near or in contact with them, the waveforms of wires 3511_1 to 3511_6 change uniformly according to the voltage changes of wires 3510_1 to 3510_6. On the other hand, when an object is near or in contact with them, the current value decreases, and therefore the waveform of the voltage value changes.

[0367] By detecting changes in capacitance in the manner described above, the proximity or contact of an object can be detected. Sometimes, a signal can be detected even when an object such as a finger or stylus is only close to the touch panel without actually touching it.

[0368] Note that, although Figure 21C An example is shown in which a common potential supplied during writing in wiring 3510 is equal to a low potential supplied during sensing; however, one embodiment of the invention is not limited to this. The common potential may also be different from the low potential.

[0369] The pulse voltage output circuit and detection circuit are preferably formed in a single IC. This IC is preferably mounted on a substrate within the housing of the touch panel or electronic device. When the touch panel is flexible, the parasitic capacitance of the curved portion of the touch panel may increase, potentially amplifying the impact of noise. From this perspective, it is preferable to use an IC employing a driving method that is less susceptible to noise. For example, it is preferable to use an IC employing a driving method that improves the signal-to-noise ratio (S / N ratio).

[0370] In this way, it is preferable to set the image writing period and the sensing period using the sensor element independently. This can prevent the sensor element's sensitivity from being reduced due to noise generated when writing data to pixels.

[0371] In one embodiment of the present invention, such as Figure 21D As shown, a frame contains one write period and one sensing period. Or, as... Figure 21E As shown, there can also be two sensing periods within a single frame. Having multiple sensing periods within a single frame can further improve detection sensitivity. For example, there can also be two to four sensing periods within a single frame.

[0372] Below, refer to Figures 22A to 22C An example of the top surface structure of the sensor elements included in the touch panel 350D is described.

[0373] Figure 22A A top view of the sensor element is shown. The sensor element includes conductive layers 56a and 56b. Conductive layer 56a serves as one electrode of the sensor element, and conductive layer 56b serves as the other electrode. The sensor element can sense the proximity or contact of an object by utilizing the capacitance formed between conductive layers 56a and 56b. Although not shown, conductive layers 56a and 56b may also have a comb-like top surface shape or a top surface shape with slits.

[0374] In one embodiment of the present invention, conductive layers 56a and 56b are also used as common electrodes of the liquid crystal element.

[0375] Multiple conductive layers 56a are disposed in the Y direction and extend in the X direction. Multiple conductive layers 56b disposed in the Y direction are electrically connected to each other through conductive layers 58 extending in the Y direction. Figure 22A An example is shown with m conductive layers 56a and n conductive layers 58.

[0376] Note that multiple conductive layers 56a can also be disposed in the X direction, in which case they can also extend in the Y direction. Multiple conductive layers 56b disposed in the X direction can also be electrically connected to each other through conductive layers 58 extending in the X direction.

[0377] like Figure 22B As shown, a conductive layer 56, serving as electrodes for sensor elements, is disposed on a plurality of pixels 60. The conductive layer 56 is equivalent to... Figure 22A Each of the conductive layers 56a and 56b. Pixel 60 is composed of multiple sub-pixels that present different colors. Figure 22B An example is shown where pixel 60 is composed of three sub-pixels (i.e., sub-pixels 60a, 60b, and 60c).

[0378] Preferably, both electrodes of the sensor element are electrically connected to the auxiliary wiring. For example... Figure 22C As shown, conductive layer 56 can also be electrically connected to auxiliary wiring 57. Note that, although Figure 22C An example is shown where auxiliary wiring is stacked on a conductive layer, but the conductive layer can also be stacked on the auxiliary wiring. Multiple conductive layers 56 arranged in the X direction can also be electrically connected to the conductive layer 58 via auxiliary wiring 57.

[0379] The resistivity of the conductive layer that allows visible light to pass through is sometimes high. Therefore, it is preferable to reduce the resistance of the pair of electrodes of the sensor element by electrically connecting the pair of electrodes of the sensor element to the auxiliary wiring.

[0380] Reducing the resistance of a pair of electrodes in a sensor element decreases the time constant of that pair of electrodes. This improves the detection sensitivity and accuracy of the sensor element.

[0381] <1-8. Touch Panel Module>

[0382] Below, refer to Figure 23 and Figures 24A to 24C The description includes an input / output device and a touch panel module of an IC according to one embodiment of the present invention.

[0383] Figure 23 A block diagram of a touch panel module 6500 is shown. The touch panel module 6500 includes a touch panel 6510 and an IC 6520. An input / output device according to one embodiment of the present invention can be adapted to the touch panel 6510.

[0384] The touch panel 6510 includes a display unit 6511, an input unit 6512, and a scan line driving circuit 6513. The display unit 6511 includes multiple pixels, multiple signal lines, and multiple scan lines, and has the function of displaying images. The input unit 6512 is used as a touch sensor by including multiple sensor elements capable of sensing the contact or proximity of a sensing object to the touch panel 6510. The scan line driving circuit 6513 has the function of outputting scan signals to the scan lines included in the display unit 6511.

[0385] Here, although for ease of explanation, the display unit 6511 and the input unit 6512 are shown separately as components of the touch panel 6510, a so-called In-Cell type touch panel that has the function of displaying images and is used as a touch sensor is preferred.

[0386] The display unit 6511 preferably has a high resolution, such as HD (1280×720 pixels), FHD (1920×1080 pixels), WQHD (2560×1440 pixels), WQXGA (2560×1600 pixels), 4K (3840×2160 pixels), or 8K (7680×4320 pixels). 4K, 8K, or higher resolutions are particularly preferred. The pixel density (resolution) of the pixels in the display unit 6511 is 300 ppi or higher, preferably 500 ppi or higher, more preferably 800 ppi or higher, further preferably 1000 ppi or higher, and even more preferably 1200 ppi or higher. Such a high-resolution and high-definition display unit 6511 can improve the realism and depth perception in personal applications such as portable and home use.

[0387] IC6520 includes circuit unit 6501, signal line driving circuit 6502, sensor driving circuit 6503, and detection circuit 6504. Circuit unit 6501 includes timing controller 6505 and image processing circuit 6506, etc.

[0388] The signal line driving circuit 6502 has the function of outputting image signals (also known as video signals) as analog signals to the signal lines included in the display unit 6511. For example, the signal line driving circuit 6502 may have a structure that combines a shift register circuit and a buffer circuit. The touch panel 6510 may include a demultiplexer circuit connected to the signal lines.

[0389] The sensor drive circuit 6503 has the function of outputting a signal for driving the sensor element included in the input section 6512. The sensor drive circuit 6503 can, for example, be a structure combining a shift register circuit and a buffer circuit.

[0390] The detection circuit 6504 has the function of outputting the output signal from the sensor element included in the input section 6512 to the circuit unit 6501. For example, the detection circuit 6504 may include an amplifier circuit and an analog-to-digital converter (ADC). In this case, the detection circuit 6504 converts the analog signal output from the input section 6512 into a digital signal and outputs it to the circuit unit 6501.

[0391] The image processing circuit 6506 included in the circuit unit 6501 has the following functions: generating and outputting signals that drive the display unit 6511 of the touch panel 6510; generating and outputting signals that drive the input unit 6512; and analyzing the signals output from the input unit 6512 and outputting the signals to the CPU 6540.

[0392] Specifically, the image processing circuit 6506 has, for example, the following functions: generating video signals according to the instructions of the CPU 6540; processing the video signals according to the specifications of the display unit 6511, converting the signals into analog video signals, and supplying the converted signals to the signal line drive circuit 6502; generating drive signals according to the instructions of the CPU 6540 and outputting them to the sensor drive circuit 6503; and analyzing the signals input from the detection circuit 6504 and outputting the analyzed signals as position information to the CPU 6540.

[0393] The timing controller 6505 has the function of generating a synchronization signal (e.g., a clock signal or a start pulse signal) included in the video signal processed by the image processing circuit 6506, and outputting the signal to the scan line drive circuit 6513 and the sensor drive circuit 6503. Furthermore, the timing controller 6505 may also have the function of generating a signal to determine the timing of the output signal of the detection circuit 6504 and outputting that signal. Here, the timing controller 6505 preferably outputs a signal synchronized with the signal output to the scan line drive circuit 6513 and a signal synchronized with the signal output to the sensor drive circuit 6503. In particular, it is preferable to separate the period for rewriting the pixel data of the display unit 6511 from the period for sensing using the input unit 6512. For example, the touch panel 6510 can be driven in such a way that a frame period is divided into a period for rewriting pixel data and a sensing period. Additionally, for example, by setting two or more sensing periods within a frame period, detection sensitivity and detection accuracy can be improved.

[0394] The image processing circuit 6506 may include, for example, a processor. For instance, a microprocessor such as a DSP (Digital Signal Processor) or GPU (Graphics Processing Unit) can be used. Such a microprocessor can also be derived from a PLD (Programmable Logic Device) such as a FPGA (Field Programmable Gate Array) or FPAA (Field Programmable Analog Array). The image processing circuit 6506 uses the processor to interpret and execute instructions from various programs, performing various data processing and program control. The programs executed by the processor can be stored in the memory area included in the processor or in a separately configured storage device.

[0395] Transistors containing oxide semiconductors in the channel formation region and having extremely small off-state currents can be used in the display section 6511 or scan line drive circuit 6513 in the touch panel 6510, circuit unit 6501 in IC 6520, signal line drive circuit 6502, sensor drive circuit 6503 or detection circuit 6504, or externally mounted CPU 6540, etc. By using transistors with extremely small off-state currents to maintain the charge (data) flowing into the capacitor used as a storage element, the long-term retention of data can be ensured. For example, by applying this characteristic to at least one of the registers and cache memory of the image processing circuit 6506, the image processing circuit 6506 can be operated only when necessary, while the previously processed data is stored in the storage element at other times, thereby achieving normally-off computing, which can reduce the power consumption of the touch panel module 6500 and the electronic device on which the touch panel module 6500 is installed.

[0396] In this example, circuit unit 6501 includes a timing controller 6505 and an image processing circuit 6506. Alternatively, the image processing circuit 6506 itself or a circuit having a portion of the functionality of the image processing circuit 6506 may be located externally. Alternatively, CPU 6540 may also have the functionality of the image processing circuit 6506 or a portion thereof. For example, circuit unit 6501 may also include a signal line driving circuit 6502, a sensor driving circuit 6503, a detection circuit 6504, and a timing controller 6505.

[0397] In this example, IC6520 includes circuit unit 6501, but circuit unit 6501 may not be included within IC6520. In this case, IC6520 may include signal line driving circuit 6502, sensor driving circuit 6503, and detection circuit 6504. For example, when the touch panel module 6500 includes multiple ICs, multiple ICs 6520 without circuit unit 6501 can be configured by setting circuit unit 6501 externally to the touch panel module 6500, or IC6520 can be configured by combining IC6520 with ICs that only include signal line driving circuit 6502.

[0398] Thus, when the IC has the function of driving the display section 6511 of the touch panel 6510 and the function of driving the input section 6512, the number of ICs installed on the touch panel module 6500 can be reduced, thereby reducing costs.

[0399] Figures 24A to 24C These are all schematic diagrams of the 6500 touch panel module equipped with IC6520.

[0400] exist Figure 24A In this design, the touch panel module 6500 includes a substrate 6531, a counter substrate 6532, multiple FPCs 6533, IC 6520, and IC 6530. The touch panel module 6500 includes a display section 6511, an input section 6512, and a scan line driving circuit 6513. IC 6520 and IC 6530 are mounted on the substrate 6531 using a COG (Copy-on-Glass) method.

[0401] IC6530 is an IC that includes only the signal line driver circuit 6502, or IC6520 that includes both the signal line driver circuit 6502 and circuit unit 6501. Signals are supplied to IC6520 and IC6530 from the outside via FPC6533. Additionally, signals can be output to the outside from at least one of IC6520 and IC6530 via FPC6533.

[0402] Figure 24A An example is shown where two scan line drive circuits 6513 are arranged to sandwich the display unit 6511. In addition to IC 6520, IC 6530 is also included. This structure is suitable for cases where the display unit 6511 has extremely high resolution.

[0403] Figure 24B An example is shown with one IC6520 and one FPC6533 installed. Thus, by concentrating functionality into a single IC6520, the number of components can be reduced, which is therefore preferable. Figure 24B In the example, the scan line drive circuit 6513 is configured along the edge of the display section 6511 that is close to the FPC 6533.

[0404] Figure 24C An example of a PCB (Printed Circuit Board) 6534 including an image processing circuit 6506 and the like is shown. ICs 6520 and 6530 on substrate 6531 are electrically connected to PCB 6534 by FPC 6533. Here, the structure described above, excluding the image processing circuit 6506, can be applied to IC 6520.

[0405] exist Figure 24A , Figure 24B and Figure 24C In the various figures, IC6520 and IC6530 may also be mounted on FPC6533 instead of on substrate 6531. For example, IC6520 and IC6530 may be mounted on FPC6533 in a COF or TAB manner.

[0406] like Figure 24A and Figure 24B As shown, the structure of arranging FPC6533 and IC6520 (and IC6530) on the short side of the display unit 6511 enables the display device to have a narrow bezel, and therefore this structure is suitable for electronic devices such as smartphones, mobile phones, or tablet terminals. Figure 24C The structure shown using PCB6534 is preferably used, for example, in television devices, monitors, tablet terminals, or notebook computers.

[0407] As described above, a display device according to one embodiment of the present invention includes a second common electrode on a substrate opposite to a substrate on which pixel electrodes and a first common electrode are disposed. By supplying the first common electrode and the second common electrode with the same potential, light leakage can be suppressed, thereby improving the display quality of the display device. Furthermore, the display device can have a high aperture ratio and high resolution. Additionally, when the second common electrode is disposed in a portion of the display area of ​​a pixel, even with the second common electrode disposed, an increase in the driving voltage of the liquid crystal element can be prevented.

[0408] This implementation method can be appropriately combined with other implementation methods.

[0409] (Implementation Method 2)

[0410] In this embodiment, refer to Figures 25A1 to 35C A transistor that can be used in a display device according to one embodiment of the present invention will be described.

[0411] The display device according to one embodiment of the present invention can be manufactured using various types of transistors, such as bottom-gate transistors or top-gate transistors. Therefore, the semiconductor layer material or transistor structure can be easily changed according to existing production lines.

[0412] Bottom-gate transistor

[0413] Figure 25A1 This is a cross-sectional view of a channel-protected transistor 410, a type of bottom-gate transistor. The transistor 410 includes an electrode 546 on a substrate 571 separated by an insulating layer 572. The transistor 410 also includes a semiconductor layer 542 on the electrode 546 separated by an insulating layer 526. The electrode 546 can serve as a gate electrode. The insulating layer 526 can serve as a gate insulating layer.

[0414] Transistor 410 includes an insulating layer 522 on the channel formation region of semiconductor layer 542. Transistor 410 includes electrodes 544a and 544b on insulating layer 526 in such a way that they are in contact with a portion of semiconductor layer 542. A portion of electrode 544a and a portion of electrode 544b are formed on insulating layer 522.

[0415] The insulating layer 522 can be used as a channel protection layer. By providing the insulating layer 522 on the channel formation region, the semiconductor layer 542 can be prevented from being exposed during the formation of electrodes 544a and 544b. This prevents the channel formation region of the semiconductor layer 542 from being etched during the formation of electrodes 544a and 544b. According to one embodiment of the present invention, a transistor with excellent electrical characteristics can be realized.

[0416] Transistor 410 includes an insulating layer 528 on electrodes 544a, 544b and insulating layer 522, and also includes an insulating layer 529 on insulating layer 528.

[0417] When an oxide semiconductor is used for semiconductor layer 542, it is preferable to use a material capable of abstracting oxygen from a portion of semiconductor layer 542 to generate oxygen vacancies in at least the regions of electrodes 544a and 544b that are in contact with semiconductor layer 542. The carrier concentration increases in the regions of semiconductor layer 542 where oxygen vacancies are generated, thereby making this region an n-type region (n... + (Layer). Therefore, this region can be used as both a source and a drain region. Examples of materials that can abstract oxygen from oxide semiconductors to create oxygen vacancies include tungsten and titanium.

[0418] By forming source and drain regions in semiconductor layer 542, the contact resistance between each of electrodes 544a and 544b and semiconductor layer 542 can be reduced. Therefore, the electrical characteristics of the transistor, such as field-effect mobility and threshold voltage, can be optimized.

[0419] When a semiconductor such as silicon is used for semiconductor layer 542, it is preferable to provide layers that are used as n-type or p-type semiconductors between semiconductor layer 542 and electrode 544a and between semiconductor layer 542 and electrode 544b. The layers used as n-type or p-type semiconductors can be used as source or drain regions in a transistor.

[0420] Insulating layers 528 and 529 are preferably formed using materials capable of preventing or reducing the diffusion of impurities from the outside into the transistor. Insulating layer 529 is not necessarily required.

[0421] When an oxide semiconductor is used for semiconductor layer 542, heat treatment can be performed once or multiple times before forming insulating layer 528, after forming insulating layer 528, or after forming insulating layer 529. By performing heat treatment, oxygen contained in insulating layers 528 and 529, or other insulating layers, can diffuse into semiconductor layer 542, thereby filling oxygen vacancies in semiconductor layer 542. Alternatively, oxygen vacancies in semiconductor layer 542 can be filled by forming one or both of insulating layers 528 and 529 while heating.

[0422] Figure 25A2 The transistor 411 shown differs from the transistor 410 in that it has an electrode 523, which can be used as a back gate, disposed on the insulating layer 529. The electrode 523 can be formed using the same material and method as the gate electrode 546.

[0423] <Back gate>

[0424] Generally, the back gate is formed using a conductive layer. The gate and back gate are configured with a channel formation region of the semiconductor layer located between them. The back gate can have the same function as the gate. The potential of the back gate can be the same as the gate electrode, or it can be GND or any other potential. By changing the potential of the back gate independently of the gate potential, the threshold voltage of the transistor can be changed.

[0425] Both electrode 546 and electrode 523 can be used as gate electrodes. Therefore, insulating layers 526, 528, and 529 can all be used as gate insulating layers. Alternatively, electrode 523 can be disposed between insulating layers 528 and 529.

[0426] When one of electrodes 546 and 523 is simply referred to as the "gate" or "gate electrode," the other can be referred to as the "back gate" or "back gate electrode." For example, in transistor 411, when electrode 523 is referred to as the "gate electrode," electrode 546 is referred to as the "back gate electrode." When electrode 523 is used as the "gate electrode," transistor 411 can be considered as a type of top-gate transistor. Furthermore, sometimes one of electrodes 546 and 523 is referred to as the "first gate" or "first gate electrode," and sometimes the other is referred to as the "second gate" or "second gate electrode."

[0427] By setting electrodes 546 and 523 with the semiconductor layer 542 in between and setting the potentials of electrodes 546 and 523 to be the same, the area through which charge carriers flow in the semiconductor layer 542 is expanded in the film thickness direction, thus increasing the amount of charge carrier movement. As a result, the on-state current and field-effect mobility of transistor 411 increase.

[0428] Therefore, transistor 411 has a large on-state current relative to its occupied area. That is, the occupied area of ​​transistor 411 relative to the required on-state current can be reduced. According to one embodiment of the invention, the occupied area of ​​the transistor can be reduced. Therefore, the display device can have a high aperture ratio or high resolution.

[0429] Furthermore, since both the gate and back gate are formed using conductive layers, they both have the function of preventing electric fields generated outside the transistor from affecting the semiconductor layer with the channel formed (especially the electric field shielding function against static electricity, etc.). When the back gate is formed to be larger than the semiconductor layer so that the semiconductor layer is covered by the back gate, the electric field shielding function can be improved.

[0430] Because both electrode 546 (gate) and electrode 523 (back gate) have the function of shielding from external electric fields, the charge generated by charged particles on the side of insulating layer 572 or above electrode 523 will not affect the channel formation region of semiconductor layer 542. As a result, degradation caused by stress testing (e.g., GBT (Gate Bias-Temperature) stress testing with a negative charge applied to the gate) can be suppressed. In addition, the variation of gate voltage (rising voltage) at which the on-state current begins to flow under different drain voltages can be mitigated. Note that this effect is obtained when electrodes 546 and 523 have the same potential or different potentials.

[0431] Note that GBT stress testing is an accelerated test that can assess changes in transistor characteristics (such as changes over time) caused by prolonged use in a short period of time. In particular, the change in the threshold voltage of the transistor before and after GBT stress testing is an important indicator for checking the reliability of the transistor. The smaller the change in threshold voltage, the higher the reliability of the transistor.

[0432] By setting electrodes 546 and 523 and ensuring their potentials are identical, the variation in threshold voltage is reduced. Consequently, the non-uniformity of electrical characteristics among multiple transistors is also reduced.

[0433] The threshold voltage variation caused by +GBT stress testing with a positive charge applied to the gate of a transistor with a back gate is also smaller than that of a transistor without a back gate.

[0434] When a light-shielding conductive film is used to form the back gate, light can be prevented from entering the semiconductor layer from the back gate side. This prevents light degradation of the semiconductor layer and degradation of electrical characteristics such as threshold voltage drift of the transistor.

[0435] Through one embodiment of the present invention, a transistor with high reliability can be realized. Furthermore, a display device with high reliability can be realized.

[0436] Figure 25B1 A cross-sectional view of a channel-protected transistor 420, one type of bottom-gate transistor, is shown. Transistor 420 has a structure substantially the same as transistor 410, but differs in that an insulating layer 522, including openings 531a and 531b, covers the semiconductor layer 542. Openings 531a and 531b are formed by selectively removing portions of the insulating layer 522 that overlap with the semiconductor layer 542.

[0437] Semiconductor layer 542 is electrically connected to electrode 544a in opening 531a. Semiconductor layer 542 is electrically connected to electrode 544b in opening 531b. By utilizing insulating layer 522, exposure of semiconductor layer 542 can be prevented during the formation of electrodes 544a and 544b. This prevents thinning of semiconductor layer 542 during the formation of electrodes 544a and 544b. The region of insulating layer 522 overlapping with the channel formation region is used as a channel protection layer.

[0438] Figure 25B2 The transistor 421 shown differs from the transistor 420 in that an electrode 523 capable of serving as a back gate is provided on the insulating layer 529.

[0439] Compared to transistors 410 and 411, transistors 420 and 421 have longer distances between electrodes 544a and 546, and between electrodes 544b and 546. Therefore, the parasitic capacitance generated between electrodes 544a and 546 can be reduced. Furthermore, the parasitic capacitance generated between electrodes 544b and 546 can also be reduced. According to one embodiment of the present invention, a transistor with excellent electrical characteristics can be realized.

[0440] Figure 25C1 The transistor 425 shown is a channel-etched transistor, a type of bottom-gate transistor. In transistor 425, electrodes 544a and 544b are formed in contact with the semiconductor layer 542 without an insulating layer 522. Therefore, portions of the semiconductor layer 542 exposed during the formation of electrodes 544a and 544b are sometimes etched. However, by not providing an insulating layer 522, transistor productivity can be improved.

[0441] Figure 25C2The transistor 426 shown differs from the transistor 425 in that an electrode 523, which can be used as a back gate, is provided on the insulating layer 529.

[0442] Top-gate transistor

[0443] Figure 26A1 This is a cross-sectional view of a transistor 430, which is a type of top-gate transistor. The transistor 430 has a semiconductor layer 542 disposed on a substrate 571 with an insulating layer 572 in between. Electrodes 544a and 544b are disposed on the semiconductor layer 542 and the insulating layer 572 and are connected to a portion of the semiconductor layer 542. An insulating layer 526 is disposed on the semiconductor layer 542, the electrodes 544a and 544b, and an electrode 546 is disposed on the insulating layer 526.

[0444] Because electrode 546 does not overlap with either electrode 544a or electrode 544b in transistor 430, the parasitic capacitance generated between electrode 546 and electrode 544a, as well as between electrode 546 and electrode 544b, can be reduced. After forming electrode 546, electrode 546 is used as a mask to introduce impurities 555 into semiconductor layer 542, thereby allowing impurity regions to be formed in semiconductor layer 542 in a self-aligned manner (see reference). Figure 26A3 According to one embodiment of the present invention, a transistor with good electrical characteristics can be realized.

[0445] Impurity 555 can be introduced using ion implantation devices, ion doping devices, or plasma processing devices.

[0446] As impurity 555, at least one element selected from Group 13 and Group 15 elements can be used, for example. When an oxide semiconductor is used as semiconductor layer 542, at least one element selected from rare gases, hydrogen, and nitrogen can also be used as impurity 555.

[0447] Figure 26A2 The difference between transistor 431 and transistor 430 is that transistor 431 has an electrode 523 and an insulating layer 527. Transistor 431 has an electrode 523 formed on an insulating layer 572 and an insulating layer 527 formed on the electrode 523. The electrode 523 can be used as a back gate. Therefore, the insulating layer 527 can be used as a gate insulating layer. The insulating layer 527 can be formed using the same material and method as the insulating layer 526.

[0448] Similar to transistor 411, transistor 431 has a large on-state current relative to its occupied area. That is, the occupied area of ​​transistor 431 relative to the required on-state current can be reduced. According to one embodiment of the invention, the occupied area of ​​the transistor can be reduced. Therefore, according to one embodiment of the invention, the display device can have a high aperture ratio or high resolution.

[0449] Figure 26B1 The transistor 440 shown is a type of top-gate transistor. The difference between transistor 440 and transistor 430 is that a semiconductor layer 542 is formed after electrodes 544a and 544b are formed. Figure 26B2 The difference between transistor 441 and transistor 440 is that transistor 441 has an electrode 523 and an insulating layer 527. Therefore, in transistors 440 and 441, a portion of the semiconductor layer 542 is formed on electrode 544a, and another portion of the semiconductor layer 542 is formed on electrode 544b.

[0450] Similar to transistor 411, transistor 441 has a large on-state current relative to its occupied area. That is, the occupied area of ​​transistor 441 relative to the required on-state current can be reduced. According to one embodiment of the invention, the occupied area of ​​the transistor can be reduced. Therefore, the display device can have a high aperture ratio or high resolution.

[0451] Figure 27A1 The transistor 442 shown is a type of top-gate transistor. The transistor 442 has electrodes 544a and 544b on the insulating layer 529. Electrodes 544a and 544b are electrically connected to the semiconductor layer 542 through openings formed in the insulating layers 528 and 529.

[0452] The portion of insulating layer 526 that does not overlap with electrode 546 is removed. A portion of insulating layer 526 included in transistor 442 extends beyond the end of electrode 546.

[0453] Using electrode 546 and insulating layer 526 as a mask, impurity 555 is introduced into semiconductor layer 542, thereby allowing impurity regions to be formed in semiconductor layer 542 in a self-aligned manner (see reference). Figure 27A3 ).

[0454] At this time, impurity 555 is not introduced into the region of semiconductor layer 542 that overlaps with electrode 546, but is introduced into the region of semiconductor layer 542 that does not overlap with electrode 546. The impurity concentration in the region of semiconductor layer 542 where impurity 555 is introduced through insulating layer 526 is lower than the impurity concentration in the region where impurity 555 is introduced without insulating layer 526. Therefore, an LDD (Lightly Doped Drain) region is formed in the region of semiconductor layer 542 adjacent to electrode 546.

[0455] Figure 27A2 The difference between transistor 443 and transistor 442 is that transistor 443 has an electrode 523 disposed below semiconductor layer 542. Electrode 523 overlaps semiconductor layer 542 through insulating layer 572. Electrode 523 can be used as a back gate electrode.

[0456] like Figure 27B1 The transistor 444 shown and Figure 27B2 As shown in transistor 445, the entire area of ​​insulating layer 526 that does not overlap with electrode 546 can be removed. Additionally, as... Figure 27C1 The transistor 446 shown and Figure 27C2 As with transistor 447 shown, the portion of insulating layer 526 other than the opening can also be left intact.

[0457] In transistors 444 to 447, after forming electrode 546, electrode 546 is used as a mask to introduce impurities 555 into semiconductor layer 542, thereby forming impurity regions in semiconductor layer 542 in a self-aligned manner.

[0458] [s-channel transistor]

[0459] Figures 28A to 28C An example of a transistor containing an oxide semiconductor is shown as semiconductor layer 542. Figure 28A This is a top view of transistor 451. Figure 28B It is along Figure 28A The cross-sectional view of the section with the dotted lines L1-L2 (cross-sectional view along the length of the channel). Figure 28C It is along Figure 28A The cross-sectional view of the section with the dotted lines W1-W2 (cross-sectional view in the direction of channel width).

[0460] Transistor 451 includes a semiconductor layer 542, an insulating layer 526, an insulating layer 572, an insulating layer 582, an insulating layer 574, an electrode 524, an electrode 543, an electrode 544a, and an electrode 544b. Electrode 543 can be used as a gate electrode, and electrode 524 can be used as a back gate electrode. Insulating layers 526, 572, 582, and 574 can all be used as gate insulating layers. Electrode 544a can be used as one of the source electrode and the drain electrode. Electrode 544b can be used as the other of the source electrode and the drain electrode.

[0461] An insulating layer 575 is disposed on a substrate 571, and an electrode 524 and an insulating layer 573 are disposed on the insulating layer 575. An insulating layer 574 is disposed on the electrode 524 and the insulating layer 573. An insulating layer 582 is disposed on the insulating layer 574, and an insulating layer 572 is disposed on the insulating layer 582.

[0462] A semiconductor layer 542a is formed on a protrusion in the insulating layer 572, and a semiconductor layer 542b is formed on the semiconductor layer 542a. Electrodes 544a and 544b are formed on the semiconductor layer 542b. The region of the semiconductor layer 542b that overlaps with electrode 544a can be used as one of the source and drain electrodes of transistor 451. The region of the semiconductor layer 542b that overlaps with electrode 544b can be used as the other of the source and drain electrodes of transistor 451.

[0463] Additionally, a semiconductor layer 542c is provided in contact with a portion of the semiconductor layer 542b. An insulating layer 526 is provided on the semiconductor layer 542c, and an electrode 543 is provided on the insulating layer 526.

[0464] Transistor 451 has the following structure: Figure 28C In this transistor, the top and side surfaces of semiconductor layer 542b, as well as the side surfaces of semiconductor layer 542a, are covered by semiconductor layer 542c. By providing semiconductor layer 542b on the protrusions of insulating layer 572, the side surfaces of semiconductor layer 542b can be covered by electrode 543. That is, transistor 451 has a structure in which the electric field of electrode 543 can electrically surround semiconductor layer 542b. This transistor structure in which a channeled semiconductor layer is electrically surrounded by the electric field of a conductive film is called a surrounded channel (S-channel) structure. A transistor with an S-channel structure is also called an "S-channel transistor".

[0465] In the s-channel structure, the channel can also be formed entirely (bulk) within the semiconductor layer 542b. The s-channel structure increases the transistor's leakage current, resulting in a larger on-state current. Furthermore, the electric field of electrode 543 can deplete the entire channel-forming region in the semiconductor layer 542b. Therefore, the s-channel structure can further reduce the transistor's off-state current.

[0466] Increasing the height of the protrusions in the insulating layer 572 and shortening the channel width can improve the effect of the s-channel structure, which increases the on-state current and reduces the off-state current. The exposed portion of the semiconductor layer 542a can be removed during the formation of the semiconductor layer 542b. In this case, the side surfaces of the semiconductor layer 542a and 542b are sometimes aligned.

[0467] An insulating layer 528 is disposed on transistor 451, and an insulating layer 529 is disposed on insulating layer 528. Electrodes 525a, 525b, and 525c are disposed on insulating layer 529. Electrode 525a is electrically connected to electrode 544a through a contact plug in an opening provided in insulating layers 529 and 528. Electrode 525b is electrically connected to electrode 544b through a contact plug in an opening provided in insulating layers 529 and 528. Electrode 525c is electrically connected to electrode 543 through a contact plug in an opening provided in insulating layers 529 and 528.

[0468] As a contact plug, for example, a highly conductive material with good embeddability such as tungsten or polycrystalline silicon can be used. The sides and bottom of the aforementioned material can be covered by a barrier layer (diffusion prevention layer) of titanium, titanium nitride, or a stack of these layers. In this case, the barrier layer is sometimes also used as part of the contact plug.

[0469] Note that when hafnium oxide, aluminum oxide, tantalum oxide, aluminum silicate, etc., are used to form the insulating layer 582, the insulating layer 582 can be used as a charge trapping layer. Injecting electrons into the insulating layer 582 can change the threshold voltage of the transistor. For example, electrons can be injected into the insulating layer 582 using the tunneling effect. Tunneling electrons can be injected into the insulating layer 582 by applying a positive voltage to the electrode 524.

[0470] Depending on the purpose, the electrode 524 that can be used as the back gate may sometimes be omitted. Figure 29A This is a top view of transistor 451a. Figure 29B It is along Figure 29A Cross-sectional view of the dashed line L1-L2 in the diagram. Figure 29C It is along Figure 29AThe cross-sectional view is shown along the dashed lines W1-W2. Transistor 451a has a structure that omits the electrodes 524, insulating layers 573, 574, and 582 found in transistor 451. By omitting these electrodes and insulating layers, the transistor's productivity can be improved. This, in turn, increases the productivity of the display device.

[0471] Figures 30A to 30C Other examples of s-channel transistors are shown. Figure 30A This is a top view of transistor 452. Figure 30B It is along Figure 30A The cross-sectional view of the dotted-dash line L1-L2. Figure 30C It is along Figure 30A The cross-sectional view of the dotted-dash line W1-W2.

[0472] Except for the side contacts between electrodes 544a and 544b and semiconductor layers 542a and 542b, transistor 452 has the same structure as transistor 451. As the insulating layer 528 covering transistor 452, an insulating layer with the same flat surface as transistor 451 can be used. Alternatively, electrodes 525a, 525b, and 525c can be disposed on the insulating layer 529.

[0473] Figure 31A and Figure 31B Other examples of s-channel transistors are shown. Figure 31A This is a top view of transistor 453. Figure 31B It is along Figure 31A The diagram shows cross-sectional views along the dashed lines L1-L2 and W1-W2. Similar to transistor 451, transistor 453 includes semiconductor layers 542a and 542b on the protrusions of insulating layer 572. Electrodes 544a and 544b are disposed on semiconductor layer 542b. The region of semiconductor layer 542b overlapping with electrode 544a can be used as one of the source and drain electrodes of transistor 453. The region of semiconductor layer 542b overlapping with electrode 544b can be used as the other of the source and drain electrodes of transistor 453. Therefore, the region 569 of semiconductor layer 542b between electrode 544a and electrode 544b can be used as a channel formation region.

[0474] In transistor 453, an opening is formed in the region overlapping with region 569 by removing a portion of insulating layer 528, and a semiconductor layer 542c is disposed along the side and bottom surfaces of the opening. An insulating layer 526 is disposed within the opening, separated from the semiconductor layer 542c, and along the side and bottom surfaces of the opening. Furthermore, an electrode 543 is disposed within the opening, separated from the semiconductor layer 542c and the insulating layer 526, and along the side and bottom surfaces of the opening.

[0475] Note that the opening is wider than semiconductor layers 542a and 542b in the cross-section along the channel width direction. Therefore, in region 569, the sides of semiconductor layers 542a and 542b are covered by semiconductor layer 542c.

[0476] An insulating layer 529 is disposed on insulating layer 528, and an insulating layer 577 is disposed on insulating layer 529. Electrodes 525a, 525b, and 525c are disposed on insulating layer 577. Electrode 525a is electrically connected to electrode 544a through a contact plug in an opening formed by removing a portion of insulating layers 577, 529, and 528. Electrode 525b is electrically connected to electrode 544b through a contact plug in an opening formed by removing a portion of insulating layers 577, 529, and 528. Electrode 525c is electrically connected to electrode 543 through a contact plug in an opening formed by removing a portion of insulating layers 577 and 529.

[0477] Depending on the purpose, the electrode 524 that can be used as the back gate may sometimes be omitted. Figure 32A This is a top view of transistor 453a. Figure 32B It is along Figure 32A The cross-sectional view is shown along the dashed lines L1-L2 and W1-W2. Transistor 453a has a structure that omits the electrodes 524, insulating layer 574, and insulating layer 582 found in transistor 453. By omitting these electrodes and insulating layers, the transistor's productivity can be improved. This, in turn, increases the productivity of the display device.

[0478] Figures 33A to 33C Other examples of s-channel transistors are shown. Figure 33A This is a top view of the transistor 454. Figure 33B It is along Figure 33A The cross-sectional view of the dotted-dash line L1-L2. Figure 33C It is along Figure 33A The cross-sectional view of the dotted-dash line W1-W2.

[0479] Transistor 454 is a type of bottom-gate transistor with a back gate electrode. In transistor 454, an electrode 543 is formed on an insulating layer 574, and an insulating layer 526 is disposed to cover the electrode 543. A semiconductor layer 542 is formed in the region of the insulating layer 526 that overlaps with the electrode 543. The semiconductor layer 542 of transistor 454 includes a stacked structure of semiconductor layers 542a and 542b.

[0480] Electrodes 544a and 544b are formed on insulating layer 526 in such a way that they contact a portion of semiconductor layer 542. An insulating layer 528 is formed on electrodes 544a and 544b in such a way that it contacts a portion of semiconductor layer 542. An insulating layer 529 is formed on insulating layer 528. An electrode 524 is formed on the region of insulating layer 529 that overlaps with semiconductor layer 542.

[0481] Electrode 524, disposed on insulating layer 529, is electrically connected to electrode 543 through openings 547a and 547b formed in insulating layers 529, 528, and 526. Thus, electrode 524 and electrode 543 are supplied with the same potential. Alternatively, one or both of openings 547a and 547b may be omitted. When both openings 547a and 547b are omitted, different potentials can be supplied to electrode 524 and electrode 543.

[0482] Depending on the purpose, the electrode 524 that can be used as the back gate may sometimes be omitted. Figure 34A This is a top view of transistor 454a. Figure 34B It is along Figure 34A The cross-sectional view of the dashed-dot line L1-L2 in the diagram. Figure 34C It is along Figure 34A The cross-sectional view is shown along the dotted lines W1-W2. Transistor 454a has a structure that omits the electrodes 524, openings 547a and 547b of transistor 454. By omitting these electrodes and openings, the transistor's productivity can be improved. Therefore, the productivity of the display device can be increased.

[0483] Figures 35A to 35C Other examples of transistors with an s-channel structure are shown. Figures 35A to 35C The transistor 448 shown has a structure that is substantially the same as that of the aforementioned transistor 447. Transistor 448 is a type of top-gate transistor with a back gate. Figure 35A This is a top view of transistor 448. Figure 35B It is along Figure 35A The cross-sectional view of the dotted-dash line L1-L2. Figure 35C It is along Figure 35A The cross-sectional view of the dotted-dash line W1-W2.

[0484] Figures 35A to 35C An example is shown where an inorganic semiconductor layer, such as a silicon layer, is used as the semiconductor layer 542 in transistor 448. Figures 35A to 35C In this structure, an electrode 524 is disposed on a substrate 571, and an insulating layer 572 is disposed on the electrode 524. In addition, a semiconductor layer 542 is formed on the protrusions of the insulating layer 572.

[0485] Semiconductor layer 542 includes semiconductor layer 542i, two semiconductor layers 542t, and two semiconductor layers 542u. Semiconductor layer 542i is disposed between the two semiconductor layers 542t. Additionally, semiconductor layer 542i and the two semiconductor layers 542t are disposed between the two semiconductor layers 542u. An electrode 543 is provided in the region overlapping with semiconductor layer 542i.

[0486] When transistor 448 is in the ON state, a channel is formed in semiconductor layer 542i. Therefore, semiconductor layer 542i is used as the channel formation region. Semiconductor layer 542t is used as the low-concentration impurity region (i.e., LDD region). Semiconductor layer 542u is used as the high-concentration impurity region. Note that one or both of the two semiconductor layers 542t may be omitted. One of the two semiconductor layers 542u is used as the source region, and the other semiconductor layer 542u is used as the drain region.

[0487] An electrode 544a disposed on insulating layer 529 is electrically connected to one of the semiconductor layers 542u through an opening 547c provided in insulating layers 526, 528, and 529. An electrode 544b disposed on insulating layer 529 is electrically connected to another of the semiconductor layers 542u through an opening 547d provided in insulating layers 526, 528, and 529.

[0488] Electrode 543, disposed on insulating layer 526, is electrically connected to electrode 524 through openings 547a and 547b in insulating layers 526 and 572. Therefore, electrodes 543 and 524 are supplied with the same potential. Alternatively, one or both of openings 547a and 547b may be omitted. When both openings 547a and 547b are omitted, electrodes 543 and 524 can be supplied with different potentials.

[0489] This implementation method can be appropriately combined with other implementation methods.

[0490] (Implementation Method 3)

[0491] In this embodiment, refer to Figure 36 , Figures 37A to 37H as well as Figure 38A and Figure 38B A touch panel module and an electronic device comprising an embodiment of the present invention will be described.

[0492] exist Figure 36 In the touch panel module 8000 shown, the touch panel 8004, frame 8009, printed circuit board 8010, and battery 8011 connected to FPC 8003 are disposed between the upper cover 8001 and the lower cover 8002.

[0493] For example, the display device of one embodiment of the present invention can be used in a touch panel 8004.

[0494] The top cover 8001 and the bottom cover 8002 can be appropriately changed in shape and size according to the size of the touch panel 8004.

[0495] The display device according to one embodiment of the present invention can be used as a touch panel. The touch panel 8004 can be a resistive touch panel or a capacitive touch panel, and can be formed to overlap with the display device according to one embodiment of the present invention. The opposing substrate (sealing substrate) of the touch panel 8004 can have the function of a touch panel. A light sensor can be provided within each pixel of the touch panel 8004, thus enabling an optical touch panel.

[0496] When using a transmissive liquid crystal element, it is also possible to... Figure 36 The backlight 8007 is configured as shown. The backlight 8007 has a light source 8008. Although in Figure 36 A light source 8008 is disposed on the backlight 8007, but one embodiment of the present invention is not limited to this structure. For example, a structure in which the light source 8008 is disposed at the end of the backlight 8007 and a light diffuser plate is provided may also be adopted. When a self-emissive light-emitting element such as an organic EL element is used, or when a reflective panel is used, the backlight 8007 may not be provided.

[0497] The bezel 8009 protects the touch panel 8004 and has electromagnetic shielding function to block electromagnetic waves generated by the operation of the printed circuit board 8010. The bezel 8009 may also function as a heat sink.

[0498] The printed circuit board 8010 includes a power supply circuit and a signal processing circuit for outputting video and clock signals. Power to the power supply circuit can be supplied by an external commercial power supply or by a separately installed battery 8011. When using a commercial power supply, the battery 8011 can be omitted.

[0499] The touch panel 8004 can also be equipped with components such as polarizers, phase difference plates, and prism sheets.

[0500] Figures 37A to 37H and Figure 38A and Figure 38BElectronic devices are shown. These electronic devices may include a housing 5000, a display unit 5001, a speaker 5003, an LED light 5004, operation keys 5005 (including a power switch or operation switch), connection terminals 5006, a sensor 5007 (which has the function of measuring factors such as force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, tilt, vibration, odor, or infrared radiation), a microphone 5008, etc.

[0501] Figure 37A A mobile computer is shown, which may include a switch 5009, an infrared port 5010, etc., in addition to the above-mentioned components. Figure 37B A portable image reproduction device (e.g., a DVD reproduction device) equipped with a recording medium is shown. In addition to the above-mentioned components, the portable image reproduction device may also include a second display unit 5002, a recording medium reading unit 5011, etc. Figure 37C A television device is shown, which may include a stand 5012, etc., in addition to the aforementioned components. The television device can be operated using the operation switch on the housing 5000 or a separately provided remote control 5013. Using the operation keys on the remote control 5013, channels and volume can be adjusted, and the image displayed on the display unit 5001 can be manipulated. A display unit can be provided in the remote control 5013 to display data output from it. Figure 37D A portable game console is shown, which may include, in addition to the aforementioned components, a recording media reading unit 5011, etc. Figure 37E A digital camera with television reception function is shown. In addition to the above, the digital camera may also include an antenna 5014, a shutter button 5015, an image receiving unit 5016, etc. Figure 37F A portable game console is shown, which may include a second display unit 5002, a recording media reading unit 5011, etc., in addition to the above-mentioned components. Figure 37G A portable television receiver is shown, which may include, in addition to the aforementioned components, a charger 5017 capable of transmitting and receiving signals. Figure 37H A watch-type information terminal is shown. In addition to the aforementioned components, this watch-type information terminal may also include a wristband 5018, a strap buckle 5019, etc. The display unit 5001, installed in a housing 5000 that also serves as a bezel, has a non-rectangular display area. The display unit 5001 can display a time icon 5020 and other icons 5021, etc. Figure 38A Display digital signage. Figure 38B The image shows a digital signboard mounted on a cylindrical column.

[0502] Figures 37A to 37H as well as Figure 38A and Figure 38B The electronic device shown can have various functions. For example, Figures 37A to 37H as well as Figure 38A and Figure 38B The electronic device shown may have the following functions: displaying various information (still images, moving images, text images, etc.) on a display unit; a touch panel; displaying calendars, dates, and times; controlling processing using various software (programs); wireless communication; connecting to various computer networks using wireless communication; sending and receiving various data using wireless communication; reading programs or data stored in a storage medium and displaying the program or data on the display unit; etc. Furthermore, an electronic device including multiple display units may have the function of displaying image information primarily on one display unit and text information on another, or the function of displaying three-dimensional images by displaying images taking parallax into account on multiple display units, etc. Moreover, an electronic device with an image receiving unit may have the following functions: capturing still images; capturing moving images; automatically or manually correcting captured images; storing captured images on a recording medium (external or built-in recording medium in the camera); displaying captured images on a display area; etc. Note that... Figures 37A to 37H as well as Figure 38A and Figure 38B The electronic device shown may have functions not limited to those described above, but may have various functions.

[0503] The electronic devices of this embodiment all have a display unit for displaying certain information. A touch panel from one embodiment of the present invention can be used for this display unit.

[0504] This implementation method can be appropriately combined with other implementation methods.

[0505] [Example 1]

[0506] In this embodiment, a liquid crystal display device according to one embodiment of the present invention will be described.

[0507] <Discussion on Semiconductor Materials>

[0508] In this embodiment, an oxide semiconductor is used as the semiconductor layer of the transistor; specifically, CAAC-OS is used.

[0509] The off-state current of a transistor using CAAC-OS (CAAC-OS FET) is lower than that of a transistor using Low Temperature Poly-Silicon (LTPS FET).

[0510] During the non-selection period after data is written, the charge gradually decreases as the off-state current flows between the source and drain of the select transistor in the pixel. This causes a change in the voltage applied to the liquid crystal molecules, making the change in optical properties visible. Therefore, display devices with high off-state currents require continuous data writing, leading to increased power consumption. The off-state current of a CAAC-OS FET is lower than that of an LTPS FET, so the charge hardly moves during the non-selection period, and the voltage applied to the liquid crystal remains unchanged. Therefore, the increase in power consumption corresponding to the number of write cycles can be prevented.

[0511]

[0512] In this embodiment, two pixel layouts with a pixel density of 1058 ppi are fabricated in FFS mode. One uses a bottom-gate top-contact (BGTC) transistor, and the other uses a top-gate self-aligned (TGSA) transistor. Orientation simulations are performed on both structures in FFS mode.

[0513] Figure 39A and Figure 39B The pixel layout using BGTC transistors is shown. Figure 39A The transistor, pixel electrode 111, and first common electrode 112 are shown. The BGTC transistor includes a gate 221, a semiconductor layer 231, and conductive layers 222a and 222b that serve as source and drain electrodes, respectively. Figure 39B From Figure 39A The top view of the common electrode 112 is omitted in the stacked structure.

[0514] exist Figure 39A and Figure 39B In this context, a conductive layer can be considered as both the scan line 228 and the gate 221. Figure 39A and Figure 39B In this context, it can also be considered as a conductive layer used as both sides of signal line 229 and conductive layer 222a.

[0515] Pixel layout using TGSA transistors and Figure 3B and Figure 3C same.

[0516] In this embodiment, a liquid crystal display device design simulator (LCDMaster 3D Full set FEM mode) manufactured by Shintech, Inc. is used, and periodic boundary conditions are employed to simulate a structure including two adjacent sub-pixels. Figure 3B or Figure 39A The subpixels shown are arranged side by side. The subpixel on the left is white (a voltage of 0V to 6V is applied to pixel electrode 111), and the subpixel on the right is black (a voltage of 0V is applied to pixel electrode 111). The size of each subpixel is 8μm × 24μm.

[0517] The simulation was conducted under the following conditions: a negative liquid crystal material (Δε=-3), a cell gap of 3.5μm, and a voltage of 0V applied to the first common electrode 112.

[0518] Figure 40A The results of orientation simulations using BGTC transistors are shown. Figure 40B The results of orientation simulations using TGSA transistors are shown. Figure 40A and Figure 40B The in-plane distribution at maximum transmittance is shown for each.

[0519] As shown in the orientation simulation results, the TGSA structure achieves higher aperture ratio, liquid crystal transmittance, and effective transmittance compared to the BGTC structure. Specifically, the aperture ratio of the TGSA structure is 37.0%, which is 1.016 times that of the BGTC structure (36.4%). The liquid crystal transmittance of the TGSA structure is 1.030 times that of the BGTC structure, and the effective transmittance of the TGSA structure is 1.044 times that of the BGTC structure.

[0520] Considering the above results, TGSA transistors will be used in subsequent discussions. In later simulations of this embodiment, two... Figure 3B The subpixels shown are arranged side by side, with the left subpixel displaying white and the right subpixel displaying black.

[0521]

[0522] Next, the orientation states of the positive liquid crystal material (Δε=3.8) and the negative liquid crystal material (Δε=-3) were compared by performing orientation simulation.

[0523] Figure 41A The results of orientation simulations using positive liquid crystal materials are shown. Figure 41B The results of orientation simulations using negative liquid crystal materials are shown. Figure 41A and Figure 41B The in-plane distribution at maximum transmittance is shown for each.

[0524] The simulations were conducted under conditions of a 3.5 μm intercellular gap, applied positive polarity, and flexural effect. Flexural effect refers to the phenomenon of polarization primarily caused by molecular shape and due to orientation distortion. Compared to positive liquid crystal materials, negative liquid crystal materials can reduce the distortion that causes flexural effect. Subsequent simulations in this embodiment were all conducted under conditions that induce flexural effect.

[0525] like Figure 41A As shown, when using positive liquid crystal material, areas where the transmittance is reduced due to alignment defects were identified within the white sub-pixels. Additionally, light leakage occurs in adjacent sub-pixels (those displaying black).

[0526] like Figure 41B As shown, when using negative liquid crystal material, the entire white sub-pixel is covered by the transmittance area. Furthermore, the light leakage observed at the edges of adjacent sub-pixels (black sub-pixels) is less compared to the case when using positive liquid crystal material.

[0527] Considering the above results, negative liquid crystal materials will be used in future discussions.

[0528] Next, the results of orientation simulations were compared when using negative liquid crystal material and applying positive or negative polarity. When applying positive polarity, simulations were performed under the condition that a voltage of 0V to 6V was applied to the pixel electrode 111 of the white sub-pixel (the left sub-pixel), and when applying negative polarity, simulations were performed under the condition that a voltage of 0V to -6V was applied to the pixel electrode 111 of the white sub-pixel.

[0529] In this embodiment, orientation simulation was performed under two conditions: in the first condition, the cell gap was 3.5 μm; in the second condition, the cell gap was 2.5 μm and a second common electrode was used (with a 0V voltage applied). The layout of the second common electrode is similar to... Figure 3B The first common electrode 112 has the same layout. In other words, the first common electrode 112 and the second common electrode have openings of the same size and located in the same position. The width of the opening ( Figure 3B The horizontal length of the opening in the first common electrode 112 shown is 3 μm.

[0530] Figure 42A and Figure 42B The results of orientation simulation are shown when the inter-cell spacing is 3.5 μm. Figure 43A and Figure 43B The results of orientation simulations are shown with a cell gap of 2.5 μm and a second common electrode (with a voltage of 0 V applied). Figures 42A to 43B The in-plane distribution at maximum transmittance is shown for each. Figure 42A and Figure 43AThis is the result when a positive voltage is applied. Figure 42B and Figure 43B The results are shown when a negative voltage is applied.

[0531] like Figure 43A and Figure 43B As shown, by reducing the inter-pixel gap to 2.5 μm and employing a second common electrode, misalignment of adjacent pixels can be reduced. Furthermore, the difference in polarity does not affect the transmittance distribution of the white-displaying sub-pixels or the degree of light leakage between adjacent pixels. Since the deviation in optical characteristics due to polarity is small, flicker in the display device is suppressed. Additionally, due to the low amount of light leakage, a large light-blocking area is not required, thus achieving a high aperture ratio.

[0532] In this embodiment, Figure 39A The pixel layout (without a second common electrode) has an aperture ratio of 36.4%. Figure 3B The pixel layout (without a second common electrode) has an aperture ratio of 37.0%. This is achieved through... Figure 3B The pixel layout employs a second common electrode, increasing the aperture ratio to 41.0%.

[0533] Next, the voltage-transmittance (VT) characteristics of the pixels were simulated. The dielectric anisotropy (Δε) was -3, -5, and -7. Figure 44 The simulation results are shown.

[0534] like Figure 44 As shown, as the absolute value of Δε increases, the saturation voltage decreases, and the curve with Δε = -7 has a maximum transmittance of about 4V.

[0535] <Manufacturing of Liquid Crystal Display Devices>

[0536] Based on the simulation results above, a transmissive liquid crystal display device is manufactured by combining a pixel layout with a second common electrode and a negative liquid crystal material.

[0537] The specifications of the display device are as follows: The diagonal size of the display section is 4.16 inches, the effective number of pixels is 3840(H)×RGB×2160(V), the resolution is 1058ppi, and the subpixel size is 8μm(H)×24μm(V).

[0538] As a display element, an FFS-mode liquid crystal element is used. A negative liquid crystal material is used. For colorization, a CF (color filter) method is used. The driving frequency is 60Hz. For video signal processing, an analog line sequential (ACS) video signal method is used. The gate driver is built-in. The analog switch is built into the source driver, using a COG (Choose-O-Gate).

[0539] The cell gap is approximately 2.5 μm by incorporating spacers with a height of approximately 2.5 μm in the display device. The dielectric anisotropy (Δε) of the liquid crystal is -8, and the refractive index anisotropy (Δn) of the liquid crystal is 0.118. The width of the opening in the second common electrode is approximately 3 μm, and the spacing between the openings in the second common electrode is approximately 5 μm.

[0540] Figure 45A This is a photograph of the display device manufactured in this embodiment displaying an image. Figure 45B and Figure 45C This is an optical microscope photograph of the display section. Figure 45B The middle is white, in Figure 45C It is displayed in green.

[0541] like Figure 45B As shown, the orientation was confirmed to be good when the pixel displays white. Figure 45C As shown, it was confirmed that when a pixel displays green, light leakage from subpixels other than the subpixel emitting green is reduced.

[0542] By combining negative liquid crystal materials with advantages of good orientation and low voltage driving with top-gate CAAC-OS FETs with advantages of low power consumption, high aperture ratio and high transmittance, a high-definition 4K liquid crystal display device with a pixel density of over 1000ppi is manufactured.

[0543] [Example 2]

[0544] In Example 1, as a condition for simulating orientation when using a negative liquid crystal material and applying positive or negative polarity, the cell gap was set to 2.5 μm and a second common electrode (applying a voltage of 0 V) ​​was used.

[0545] This embodiment shows the results of an orientation simulation focusing on the width of the opening for the cell gap and the second common electrode.

[0546] In this embodiment, a liquid crystal display device design simulator (LCDMaster 3D Full set FEM mode) manufactured by Shintech, Inc. is used, and periodic boundary conditions are employed to simulate a structure including two adjacent sub-pixels. Figure 3B The subpixels shown are arranged side-by-side. The left subpixel displays white (with a voltage of 0V to 6V applied to pixel electrode 111), and the right subpixel displays black (with a voltage of 0V applied to pixel electrode 111). Each subpixel has a size of 8μm × 24μm. The width of the opening (…) Figure 3B The horizontal length of the opening of the first common electrode 112 shown is 3 μm.

[0547] The simulation was conducted under the following conditions: using a negative liquid crystal material (Δε=-3), a voltage of 0V was applied to the first common electrode 112 and the second common electrode.

[0548] First, orientation simulations were performed under the following five conditions: the width of the opening in the second common electrode was 2 μm, 3 μm, 4 μm, 5 μm, and 8 μm. The width of the opening in the second common electrode was equal to... Figure 1A and Figure 1B The length L1 of the region where the second common electrode 244 is not located is shown. As mentioned above, the size of each sub-pixel is 8μm × 24μm. The condition of length L1 = 8μm is equivalent to the condition of not setting the second common electrode in the sub-pixel. When the length L1 = 3μm, the layout of the second common electrode can be considered as... Figure 3B The first common electrode 112 is the same. Note that the unit cell spacing is 3 μm.

[0549] In this embodiment, transmittance and contrast are calculated through orientation simulation. Here, transmittance refers to the average transmittance of the sub-pixels displaying white. Contrast is obtained by dividing the average transmittance of the sub-pixels displaying white by the average transmittance of the sub-pixels displaying black.

[0550] Figure 46A The simulation results of the voltage-transmittance characteristics are shown. Figure 46B The simulation results of the transmittance-contrast characteristics are shown. These results indicate that, for the same transmittance, the smaller the opening width of the second common electrode, the higher the contrast. Furthermore, it is shown that the larger the opening width of the second common electrode, the lower the voltage at maximum transmittance.

[0551] Next, orientation simulations were performed under the following three conditions: cell gaps of 2.5 μm, 2.75 μm, and 3 μm. Note that the opening widths of both the first and second common electrodes are 3 μm.

[0552] Figure 47A The simulation results of the voltage-transmittance characteristics are shown. Figure 47B The simulation results of transmittance-contrast characteristics are shown. These results show that the smaller the cell gap, the higher the contrast, and the larger the cell gap, the higher the transmittance.

[0553] This application is based on Japanese Patent Application No. 2016-050824, filed with the Japan Patent Office on March 15, 2016, and Japanese Patent Application No. 2016-101543, filed with the Japan Patent Office on May 20, 2016, the entire contents of which are incorporated herein by reference.

[0554] Symbol Explanation

[0555] 34: Capacitor; 40: Liquid Crystal Element; 45: Light; 51: Substrate; 56: Conductive Layer; 56a: Conductive Layer; 56b: Conductive Layer; 57: Auxiliary Wiring; 58: Conductive Layer; 60: Pixel; 60a: Subpixel; 60b: Subpixel; 60c: Subpixel; 61: Substrate; 62: Display Unit; 63: Connecting Unit; 64: Driving Circuit Unit; 65: Wiring; 66: Non-Display Area; 68: Display Area; 68a: Display Area; 68b: Display Area; 69: Connecting Unit; 72: FPC; 72a: FPC; 72b: FPC; 73: IC; 73a: IC; 73b: IC 81: Scan line; 82: Signal line; 100A: Display device; 100B: Display device; 100C: Display device; 100D: Display device; 100E: Display device; 100F: Display device; 111: Pixel electrode; 111a: Pixel electrode; 111b: Pixel electrode; 112: First common electrode; 112a: First common electrode; 112b: First common electrode; 113: Liquid crystal layer; 117: Spacer; 119a: Substrate; 119b: Substrate; 121: Protective layer; 122: Insulating layer; 123: Insulating layer; 124: Electrode 125: Insulating layer 126: Conductive layer 127: Electrode 128: Electrode 130: Polarizer 131: Coloring layer 132: Light-shielding layer 132a: Light-shielding layer 132b: Light-shielding layer 133a: Alignment film 133b: Alignment film 137: Wiring 138: Wiring 139: Auxiliary wiring 141: Adhesive layer 160: Protective substrate 161: Backlight 162: Substrate 163: Adhesive layer 164: Adhesive layer 165: Polarizer 166: Polarizer 167: Adhesive layer 168: Adhesive layer 169: Adhesive layer Layer 201: Transistor 204: Connector 206: Transistor 211: Insulating layer 212: Insulating layer 213: Insulating layer 214: Insulating layer 215: Insulating layer 216: Insulating layer 220: Insulating layer 221: Gate 222a: Conductive layer 222b: Conductive layer 223: Gate 228: Scan line 229: Signal line 231: Semiconductor layer 231a: Channel region 231b: Low resistance region 242: Connector 242b: Connector 243: Connector 244: Second common electrode 244a: Second common electrode 244b: Second common electrode 244c: Second common electrode 251: Conductive layer 281: Conductive layer 282: Conductive layer 283: Conductive layer 284: Conductive layer 285: Conductive layer 286: Conductive layer 350A: Touch panel 350B: Touch panel 350D: Touch panel 360: Area 370: Display device 375: Input device 376: Input device 379: Display device 410: Transistor 411: Transistor 415: Input device 416: Substrate 420: Transistor421: Transistor 425: Transistor 426: Transistor 430: Transistor 431: Transistor 440: Transistor 441: Transistor 442: Transistor 443: Transistor 444: Transistor 445: Transistor 446: Transistor 447: Transistor 448: Transistor 449: IC 450: FPC 451: Transistor 451a: Transistor 452: Transistor 453: Transistor 453a: Transistor 454: Transistor 454a: Transistor 461: Conductive Film 462: Conductive Film 463: Conductive Film 464: Nanowire 471: Electrode 472: Electrode 473: Electrode 474: Bridged Electrode 476: Wiring 477: Wiring 522: Insulating Layer 523: Electrode 524: Electrode 524a: Electrode 524b: Electrode 525a: Electrode 525b: Electrode 525c: Electrode 526: Insulating Layer 527: Insulating Layer 528: Insulating Layer 529: Insulating layer; 531a: Opening; 531b: Opening; 542: Semiconductor layer; 542a: Semiconductor layer; 542b: Semiconductor layer; 542c: Semiconductor layer; 542i: Semiconductor layer; 542t: Semiconductor layer; 542u: Semiconductor layer; 543: Electrode; 544a: Electrode; 544b: Electrode; 546: Electrode; 547a: Opening; 547b: Opening; 547c: Opening; 547d: Opening; 555: Impurity; 569: Region; 571: Substrate; 572: Insulating layer; 573: Insulating layer; 574: Insulating layer; 575: Insulating layer; 577: Insulating layer; 582: Insulating layer 601: Pulse voltage output circuit 602: Current sensing circuit 603: Capacitor 621: Electrode 622: Electrode 3501: Wiring 3502: Wiring 3510: Wiring 3511: Wiring 3515_1: Block 3515_2: Block 3516: Block 5000: Housing 5001: Display unit 5002: Display unit 5003: Speaker 5004: LED light 5005: Operation key 5006: Connection terminal 5007: Sensor 5008: Microphone 5009: Switch 5010: Infrared port 5011: Recording medium 5012: Image Reading Unit; 5013: Stand; 5014: Remote Control Unit; 5015: Shutter Button; 5016: Image Receiver; 5017: Charger; 5018: Wristband; 5019: Watch Strap Buckle; 5020: Icon; 5021: Icon; 6500: Touch Panel Module; 6501: Circuit Unit; 6502: Signal Line Drive Circuit; 6503: Sensor Drive Circuit; 6504: Detection Circuit; 6505: Timing Controller; 6506: Image Processing Circuit; 6510: Touch Panel; 6511: Display Unit; 6512: Input Unit; 6513: Scan Line Drive Circuit6520: IC; 6530: IC; 6531: Substrate; 6532: Opposite Substrate; 6533: FPC; 6534: PCB; 6540: CPU; 8000: Touch Panel Module; 8001: Top Cover; 8002: Bottom Cover; 8003: FPC; 8004: Touch Panel; 8007: Backlight; 8008: Light Source; 8009: Bezel; 8010: Printed Circuit Board; 8011: Battery

Claims

1. A display device comprising pixels, in, The pixel includes multiple sub-pixels. Each of the multiple sub-pixels includes a display area. The display device includes a first common electrode, a second common electrode, pixel electrodes, and a liquid crystal layer. The liquid crystal layer is sandwiched between the first common electrode and the second common electrode, which are supplied with the same potential. The first common electrode includes a portion overlapping the second common electrode between the display areas of two adjacent sub-pixels that display different colors. The second common electrode includes an opening in the display area of ​​the sub-pixel. Either the first common electrode or the pixel electrode includes a portion in the display area of ​​the sub-pixel that does not overlap with the second common electrode. When the thickness of the liquid crystal layer is represented by d, the width of the opening is greater than or equal to d / 2 and narrower than the width of the sub-pixel. When the thickness of the liquid crystal layer is represented by d, the spacing between the openings of two adjacent sub-pixels is more than 1.2d and less than 2.4d. Furthermore, the thickness of the liquid crystal layer is 1.5 μm or more and 3 μm or less.

2. The display device according to claim 1, The first common electrode is electrically connected to the second common electrode.

3. The display device according to claim 1, The liquid crystal contained in the liquid crystal layer has negative dielectric anisotropy.

4. The display device according to claim 1, further comprising a transistor, The transistor includes a semiconductor layer. The semiconductor layer includes an oxide semiconductor in the channel formation region. Furthermore, the pixel electrode is electrically connected to the transistor.

5. The display device according to claim 4, The semiconductor layer includes: One of aluminum, gallium, yttrium, and tin; indium; and zinc.

6. The display device according to claim 1 further includes scan lines and signal lines. The extension direction of the scan line intersects the extension direction of the signal line. Furthermore, the arrangement direction of the plurality of sub-pixels that present the same color intersects with the extension direction of the signal line.

7. The display device according to claim 1, The first common electrode includes an opening in the display area of ​​the sub-pixel. Furthermore, in the cross-sectional view of the display device, the width of the opening of the second common electrode is equal to the width of the opening of the first common electrode.

8. The display device according to claim 7, In the cross-sectional view of the display device, the width of the opening in the second common electrode is greater than the width of the opening in the first common electrode.

9. The display device according to claim 7, In the cross-sectional view of the display device, the width of the opening in the second common electrode is smaller than the width of the opening in the first common electrode.

10. A module comprising: The display device according to claim 1; as well as Flexible printed circuit boards or integrated circuits.

11. An electronic device, comprising: The module according to claim 10; as well as Antenna, battery, casing, camera, speaker, microphone, or operation buttons.

Images