Display device, display module and electronic device

Abstract

The present invention provides a display device, a display module, and an electronic device. The liquid crystal element includes a pixel electrode, a liquid crystal layer, and a common electrode. The scanning line and the signal line are both electrically connected to the transistor. The scanning line and the signal line both include a metal layer. The transistor is electrically connected to the pixel electrode. The semiconductor layer of the transistor includes a stack of a first metal oxide layer and a second metal oxide layer. The first metal oxide layer includes a region having a lower crystallinity than the second metal oxide layer. The transistor includes a first region connected to the pixel electrode. The pixel electrode, the common electrode, and the first region all have a function of transmitting visible light. The visible light passes through the first region and the liquid crystal element and is emitted from the display device.

Description

[0001] This divisional application is a divisional application of a Chinese patent application with the application number 201711231700.1, the filing date of November 30, 2017, and the invention title of "Display Device, Display Module, and Electronic Device". Technical Field

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

[0003] Note that one aspect of the present invention is not limited to the above technical field. As an example of the technical field of one aspect of the present invention, semiconductor devices, display devices, light-emitting devices, power storage devices, storage devices, electronic devices, lighting devices, input devices (e.g., touch sensors, etc.), input / output devices (e.g., touchscreens, etc.), and driving methods or manufacturing methods of the above devices can be cited. Background Art

[0004] Most flat panel displays for liquid crystal display devices and light-emitting display devices are composed of transistors using silicon semiconductors such as amorphous silicon, single-crystalline silicon, or polycrystalline silicon provided on a glass substrate. In addition, transistors using such silicon semiconductors are also used for integrated circuits (ICs) and the like.

[0005] In recent years, a technique of using a metal oxide exhibiting semiconductor characteristics in place of a silicon semiconductor for a transistor has attracted attention. Note that in this specification, a metal oxide exhibiting semiconductor characteristics is referred to as an oxide semiconductor. For example, Patent Document 1 and Patent Document 2 have disclosed techniques of manufacturing a transistor using zinc oxide or In-Ga-Zn oxide as an oxide semiconductor and using the transistor as a switching element of a pixel of a display device.

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-123861

[0007] [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-96055 Summary of the Invention

[0008] One of the objects of one aspect of the present invention is to provide a liquid crystal display device with a high aperture ratio. In addition, one of the objects of one aspect of the present invention is to provide a liquid crystal display device with low power consumption. In addition, one of the objects of one aspect of the present invention is to provide a liquid crystal display device with high resolution. In addition, one of the objects of one aspect of the present invention is to provide a liquid crystal display device with high reliability.

[0009] Note that the description of these objectives does not preclude the existence of other objectives. One embodiment of the present invention does not need to achieve all of the above objectives. Objectives other than the above can be extracted from the descriptions in the specification, drawings, and claims.

[0010] One embodiment of the present invention is a display device including a liquid crystal element, a transistor, a scanning line, and a signal line. The liquid crystal element includes a pixel electrode, a liquid crystal layer, and a common electrode. Both the scanning line and the signal line are electrically connected to the transistor. Both the scanning line and the signal line include a metal layer. The transistor is electrically connected to the pixel electrode. The semiconductor layer of the transistor includes a stack of a first metal oxide layer and a second metal oxide layer. The first metal oxide layer includes a region with lower crystallinity than the second metal oxide layer. The transistor includes a first region connected to the pixel electrode. The pixel electrode, the common electrode, and the first region all have a function of transmitting visible light. The visible light passes through the first region and the liquid crystal element and is emitted from the display device.

[0011] One embodiment of the present invention is a display device including a liquid crystal element, a transistor, a scanning line, and a signal line. The liquid crystal element includes a pixel electrode, a liquid crystal layer, and a common electrode. Both the scanning line and the signal line are electrically connected to the transistor. Both the scanning line and the signal line include a metal layer. The transistor is electrically connected to the pixel electrode. The transistor includes: a gate electrode; an insulating layer on the gate electrode; a semiconductor layer on the insulating layer; and a pair of electrodes on the semiconductor layer. The semiconductor layer includes a first metal oxide layer and a second metal oxide layer on the first metal oxide layer. The first metal oxide layer includes a region with lower crystallinity than the second metal oxide layer. The transistor includes a first region connected to the pixel electrode. The pixel electrode, the common electrode, and the first region all have a function of transmitting visible light. The visible light passes through the first region and the liquid crystal element and is emitted from the display device.

[0012] Preferably, the first metal oxide layer and the second metal oxide layer each independently contain indium, metal M (M is aluminum, gallium, yttrium, or tin), and zinc. For example, when the atomic ratio of indium, metal M, and zinc is In:M:Zn = 4:x:y, x is 1.5 or more and 2.5 or less, and y is 2 or more and 4 or less. For example, when the atomic ratio of indium, metal M, and zinc is In:M:Zn = 5:x:y, x is 0.5 or more and 1.5 or less, and y is 5 or more and 7 or less.

[0013] The second metal oxide layer preferably includes a crystalline portion having a c-axis orientation.

[0014] The display device having the above structure may further include a touch sensor. The touch sensor is closer to the display surface side than the liquid crystal element and the transistor.

[0015] The scanning line preferably has a portion overlapping with the semiconductor layer.

[0016] Visible light can also pass through the first region and the liquid crystal element in sequence and then be emitted from the display device. In addition, visible light can also pass through the liquid crystal element and the first region in sequence and then be emitted from the display device.

[0017] The extending direction of the scanning line preferably intersects with the extending direction of the signal line. The direction in which a plurality of pixels presenting the same color are arranged preferably intersects with the extending direction of the signal line.

[0018] One embodiment of the present invention is a display module including a display device having any one of the above structures. The display module is mounted with connectors such as a flexible printed circuit (hereinafter referred to as FPC) or a TCP (Tape Carrier Package), or an IC is mounted by a method such as a COG (Chip On Glass) method or a COF (Chip On Film) method.

[0019] One embodiment of the present invention is an electronic device, including: the above display module; and at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operation button.

[0020] According to one embodiment of the present invention, a liquid crystal display device with a high aperture ratio can be provided. In addition, according to one embodiment of the present invention, a liquid crystal display device with low power consumption can be provided. In addition, according to one embodiment of the present invention, a liquid crystal display device with high resolution can be provided. In addition, according to one embodiment of the present invention, a liquid crystal display device with high reliability can be provided.

[0021] Note that the description of these effects does not prevent the existence of other effects. One embodiment of the present invention does not necessarily achieve all of the above effects. Effects other than the above can be extracted from the description of the specification, drawings, and claims. Description of the Drawings

[0022] Figure 1 is a perspective view showing an example of the display device;

[0023] Figures 2A to 2C is a cross-sectional view showing an example of the display device;

[0024] Figure 3A and Figure 3B is a cross-sectional view showing an example of the display device;

[0025] Figure 4A and Figure 4B is a top view showing an example of a sub-pixel;

[0026] Figure 5A andFigure 5B is a top view showing an example of a sub-pixel;

[0027] Figure 6 is a cross-sectional view showing an example of a display device;

[0028] Figure 7 is a cross-sectional view showing an example of a display device;

[0029] Figures 8A to 8D is a cross-sectional view showing an example of a display device;

[0030] Figure 9A and Figure 9B is a diagram showing an example of the pixel configuration and a structural example;

[0031] Figure 10A and Figure 10B is a perspective view showing an example of a display device;

[0032] Figure 11A and Figure 11B is a perspective view showing an example of a display device;

[0033] Figures 12A to 12C is a diagram showing an example of an operation mode;

[0034] Figure 13A and Figure 13B is a block diagram and a timing diagram of a touch sensor;

[0035] Figure 14A and Figure 14B is a block diagram and a timing diagram of a display device;

[0036] Figures 15A to 15D is a diagram explaining the operations of the display unit and the touch sensor;

[0037] Figures 16A to 16D is a diagram explaining the operations of the display unit and the touch sensor;

[0038] Figures 17A to 17C is a diagram showing an example of an electronic device;

[0039] Figures 18A to 18C is a diagram showing an example of an electronic device;

[0040] Figure 19 is a cross-sectional view explaining the display device of Example 1;

[0041] Figure 20 is a diagram showing the light transmittance of the stacked structure of the display device of Example 1;

[0042] Figure 21A1 、 Figure 21A2 、 Figure 21B1, Figure 21B2 , Figure 21C1 and Figure 21C2 are diagrams illustrating the manufacturing method of the display device of Example 2;

[0043] Figure 22A1 , Figure 22A2 , Figure 22B1 , Figure 22B2 , Figure 22C1 , Figure 22C2 , Figure 22D1 and Figure 22D2 are diagrams illustrating the manufacturing method of the display device of Example 2;

[0044] Figure 23 is a diagram showing the light transmittance of the stacked structure of the display device of Example 2.

[0045] The selected diagram of the present invention is Figures 2A to 2C . Detailed Embodiments

[0046] 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 it is easily understandable for those of ordinary skill in the art that the manner and details can be changed into various forms without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited only to the content described in the following embodiments.

[0047] Note that in the inventive structures described below, the same reference numerals are used in different drawings to denote the same parts or parts having the same functions, and repeated descriptions are omitted. In addition, when denoting parts having the same functions, the same hatching is sometimes used without particularly attaching reference numerals.

[0048] In addition, for ease of understanding, the positions, sizes, and ranges of the respective components shown in the drawings do not necessarily represent their actual positions, sizes, and ranges, etc. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and ranges disclosed in the drawings.

[0049] In addition, depending on the situation or state, "film" and "layer" can be interchanged with each other. For example, sometimes "conductive layer" can be changed to "conductive film". In addition, sometimes "insulating film" can be changed to "insulating layer".

[0050] In this specification and the like, a metal oxide refers to an oxide of a metal in a broad sense. Metal oxides are classified into oxide insulators, oxide conductors (including transparent oxide conductors), and oxide semiconductors (Oxide Semiconductor, which may also be abbreviated as OS), etc. For example, when a metal oxide is used for the semiconductor layer of a transistor, the metal oxide is sometimes referred to as an oxide semiconductor. In other words, an OS FET can be called a transistor including a metal oxide or an oxide semiconductor.

[0051] In this specification and the like, a metal oxide containing nitrogen is sometimes referred to as a metal oxide. In addition, a metal oxide containing nitrogen can also be referred to as a metal oxynitride.

[0052] Embodiment 1

[0053] In this embodiment, refer to Figures 1 to 11B A display device according to one aspect of the present invention will be described.

[0054] 〈1. Structural example 1 of the display device〉

[0055] First, refer to Figures 1 to 5B A display device according to this embodiment will be described.

[0056] The display device according to this embodiment includes a liquid crystal element and a transistor. The liquid crystal element includes a pixel electrode, a liquid crystal layer, and a common electrode. The transistor is electrically connected to the pixel electrode. The semiconductor layer of the transistor includes a stack of a first metal oxide layer and a second metal oxide layer. The first metal oxide layer includes a region with lower crystallinity than the second metal oxide layer. The transistor includes a first region connected to the pixel electrode. The pixel electrode, the common electrode, and the first region all have a function of transmitting visible light. Visible light passes through the first region and the liquid crystal element and is emitted from the display device.

[0057] In addition, the display device according to this embodiment includes a liquid crystal element and a transistor. The liquid crystal element includes a pixel electrode, a liquid crystal layer, and a common electrode. The transistor is electrically connected to the pixel electrode. The transistor includes: a gate electrode; an insulating layer on the gate electrode; a semiconductor layer on the insulating layer; and a pair of electrodes on the semiconductor layer. The semiconductor layer includes a first metal oxide layer and a second metal oxide layer on the first metal oxide layer. The first metal oxide layer includes a region with lower crystallinity than the second metal oxide layer. The transistor includes a first region connected to the pixel electrode. The pixel electrode, the common electrode, and the first region all have a function of transmitting visible light. Visible light passes through the first region and the liquid crystal element and is emitted from the display device.

[0058] In the display device of the present embodiment, the contact portion between the transistor and the pixel electrode allows visible light to pass through, so this contact portion can be provided in the display area. As a result, the aperture ratio of the pixel can be increased. The higher the aperture ratio, the higher the light extraction efficiency. When the light extraction efficiency is improved, the brightness of the backlight unit is also reduced. Therefore, the power consumption of the display device can be reduced. In addition, high resolution of the display device can be achieved.

[0059] The display device of the present embodiment further includes a scan line and a signal line. Both the scan line and the signal line are electrically connected to the transistor. Both the scan line and the signal line include a metal layer. By using the metal layer for the scan line and the signal line, the resistance values of the scan line and the signal line can be reduced.

[0060] In addition, the scan line preferably has a portion overlapping with the channel region of the transistor. Depending on the material used for the channel region of the transistor, when irradiated with light, the characteristics of the transistor may sometimes change. When the scan line has a portion overlapping with the channel region of the transistor, it is possible to suppress the irradiation of external light or light from the backlight to the channel region. As a result, the reliability of the transistor can be improved. In addition, a single conductive film can also function as both the scan line and the gate (or back gate).

[0061] In one aspect of the present invention, the following transparent semiconductor materials and conductive materials can be used for transistors, wirings, capacitors, etc.

[0062] The semiconductor film included in the transistor can be formed using a transparent semiconductor material. Examples of the transparent semiconductor material include metal oxides, oxide semiconductors, etc. The oxide semiconductor preferably contains at least indium (In). In particular, it preferably contains indium (In) and zinc (Zn). In addition, in addition to this, it may also contain one or more selected from aluminum (Al), gallium (G), yttrium (Y), tin (Sn), copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium, etc.

[0063] The conductive film included in the transistor can be formed using a transparent conductive material. The transparent conductive material preferably contains one or more selected from indium, zinc, and tin. Specifically, indium oxide, indium-tin oxide (also known as ITO: Indium Tin Oxide), indium-zinc oxide, indium-tungsten oxide, indium-tungsten-zinc oxide, indium-titanium oxide, indium-tin-titanium oxide, indium-tin-silicon oxide, zinc oxide, gallium-zinc oxide, etc. can be cited.

[0064] In addition, the conductive film included in the transistor may also be formed of an oxide semiconductor that has been made to have a low resistance by containing an impurity element or the like. This oxide semiconductor that has been made to have a low resistance may be referred to as an oxide conductor (OC: Oxide Conductor).

[0065] For example, the oxide conductor is obtained by the following steps: oxygen defects are formed in the oxide semiconductor, and hydrogen is added to the oxygen defects, thereby forming donor energy levels near the conduction band. Since donor energy levels are formed in the oxide semiconductor, the oxide semiconductor has high conductivity and becomes a conductor.

[0066] Note that the oxide semiconductor has a large energy gap (for example, the energy gap is 2.5 eV or more), and thus is transparent to visible light. In addition, as described above, the oxide conductor is an oxide semiconductor having donor energy levels near the conduction band. Therefore, the influence of absorption due to the donor energy levels of the oxide conductor is small, and it has the same degree of light transmittance to visible light as the oxide semiconductor.

[0067] In addition, the oxide conductor preferably contains one or more metal elements included in the semiconductor film of the transistor. By using oxide semiconductors containing the same metal element for two or more of the layers constituting the transistor, manufacturing apparatuses (for example, a film forming apparatus, a processing apparatus, etc.) can be used in common in two or more processes, so that the manufacturing cost can be suppressed.

[0068] Figure 1 is a perspective view of the display device 100A. In Figure 1 for clarity, components such as the polarizing plate 130 are omitted. In Figure 1 the substrate 61 is indicated by a dashed line. Figure 2A and Figure 3A are cross-sectional views of the display device 100A. Figure 2B is an enlarged view of the transistor 201 included in the display device 100A, Figure 2C is an enlarged view of the transistor 206 included in the display device 100A. Figure 3B is a modified example of the transistor 206 included in the display device 100A.

[0069] The display device 100A includes a display unit 62 and a drive circuit unit 64. An FPC 72 and an IC 73 are mounted on the display device 100A.

[0070] The display unit 62 includes a plurality of pixels and has a function of displaying an image.

[0071] A pixel includes a plurality of sub-pixels. For example, by using a sub-pixel that presents red, a sub-pixel that presents green, and a sub-pixel that presents blue to form a pixel, the display unit 62 can perform full-color display. Note that the colors presented by the sub-pixels are not limited to red, green, and blue. In a pixel, for example, sub-pixels that present colors such as white, yellow, magenta, and cyan can also be used. In this specification and the like, the sub-pixels are sometimes simply referred to as pixels.

[0072] The display device 100A may include either or both of a scan line driving circuit and a signal line driving circuit, or may not include both of the scan line driving circuit and the signal line driving circuit. In the case where the display device 100A includes a sensor such as a touch sensor, the display device 100A may also include a sensor driving circuit. In the present embodiment, an example of including a scan line driving circuit as the driving circuit unit 64 is shown. The scan line driving circuit has a function of outputting a scan signal to the scan lines included in the display unit 62.

[0073] In the display device 100A, the IC 73 is mounted on the substrate 51 by a mounting method such as the COG method. The IC 73 includes, for example, one or more of a signal line driving circuit, a scan line driving circuit, and a sensor driving circuit.

[0074] The FPC 72 is electrically connected to the display device 100A. Signals and power are supplied from the outside to the IC 73 and the driving circuit unit 64 through the FPC 72. In addition, signals can be output from the IC 73 to the outside through the FPC 72.

[0075] In addition, an IC may be mounted on the FPC 72. For example, an IC including one or more of a signal line driving circuit, a scan line driving circuit, and a sensor driving circuit may be mounted on the FPC 72.

[0076] Signals and power are supplied from the wiring 65 to the display unit 62 and the driving circuit unit 64. The signals and power are input to the wiring 65 from the IC 73 or from the outside through the FPC 72.

[0077] Figure 2A and Figure 3A is a cross-sectional view including the display unit 62, the driving circuit unit 64, and the wiring 65. In Figure 2A subsequent cross-sectional views of the display device, as the display unit 62, a display region 68 of one sub-pixel and a non-display region 66 located around it are shown.

[0078] In Figure 2AIn [Example], an example is shown in which the polarizer 130 is located on one side of the substrate 61 and the backlight unit (not shown) is located on one side of the substrate 51. First, the light 45 from the backlight unit is incident on the substrate 51, and successively passes through the contact portion between the transistor 206 and the pixel electrode 111, the liquid crystal element 40, the coloring layer 131, the substrate 61, and the polarizer 130 and is emitted to the outside of the display device 100A.

[0079] In Figure 3A In [Example], an example is shown in which the polarizer 130 is located on one side of the substrate 51 and the backlight unit (not shown) is located on one side of the substrate 61. First, the light 45 from the backlight unit is incident on the substrate 61, and successively passes through the coloring layer 131, the liquid crystal element 40, the contact portion between the transistor 206 and the pixel electrode 111, the substrate 51, and the polarizer 130 and is emitted to the outside of the display device 100A.

[0080] Thus, in the display device of the present embodiment, without changing the structure between the substrate 51 and the substrate 61, either the surface on the side of the substrate 51 or the surface on the side of the substrate 61 can be used as the display surface. Which of the above surfaces is used as the display surface can be appropriately determined according to the configurations of the backlight unit, the polarizer, the touch sensor, etc.

[0081] Although hereinafter [Example] Figure 2A is taken as an example for description, Figure 3A it is the same here.

[0082] The display device 100A is an example of a transmissive liquid crystal display device using a liquid crystal element of the in-plane switching (IPS) mode.

[0083] As Figure 2A shown, the display device 100A includes the substrate 51, the transistor 201, the transistor 206, the liquid crystal element 40, the alignment film 133a, the alignment film 133b, the connection portion 204, the adhesive layer 141, the coloring layer 131, the light-shielding layer 132, the protective layer 121, the substrate 61, the polarizer 130, etc.

[0084] The transistor 206 is provided in the non-display area 66. Figure 2C An enlarged view of the transistor 206 is shown.

[0085] The transistor 206 includes a gate 221, an insulating layer 213, a conductive layer 222a, a conductive layer 222c, and a semiconductor layer 231.

[0086] The gate 221 overlaps with the semiconductor layer 231 with the insulating layer 213 therebetween. The insulating layer 213 is used as a gate insulating layer. Both the conductive layer 222a and the conductive layer 222c are connected to the semiconductor layer 231.

[0087] In Figure 2AIn this case, the pixel electrode 111 included in the liquid crystal element 40 is electrically connected to the semiconductor layer 231 through the conductive layer 222c.

[0088] The conductive layer 222c is formed of a material that transmits visible light. Thereby, the contact portion between the pixel electrode 111 and the transistor can be provided in the display region 68. Therefore, the aperture ratio of the sub-pixel can be increased. In addition, the power consumption of the display device can be reduced.

[0089] As Figure 2C shown, the semiconductor layer 231 includes a first metal oxide layer 231a and a second metal oxide layer 231b on the first metal oxide layer 231a.

[0090] Preferably, both the first metal oxide layer 231a and the second metal oxide layer 231b contain In, M (M is Ga, Al, Y or Sn), and Zn.

[0091] When the regions where the atomic ratio of In in the first metal oxide layer 231a and the second metal oxide layer 231b is greater than the atomic ratio of M are included, the field-effect mobility of the transistor can be increased, so it is preferred. As an example, the atomic ratios of In, M, and Zn in the first metal oxide layer 231a and the second metal oxide layer 231b are preferably In:M:Zn = 4:2:3 or around it, or In:M:Zn = 5:1:7 or around it. Here, "around" includes the following cases: when In is 4, M is 1.5 or more and 2.5 or less, and Zn is 2 or more and 4 or less; and when In is 5, M is 0.5 or more and 1.5 or less, and Zn is 5 or more and 7 or less. In this way, by making the first metal oxide layer 231a and the second metal oxide layer 231b have substantially the same composition, the same sputtering target can be used, so the manufacturing cost can be suppressed.

[0092] The first metal oxide layer 231a and the second metal oxide layer 231b can also be formed of films using targets with different compositions, but it is particularly preferred to use a stacked film continuously formed using a target with the same composition in a manner that does not expose to the atmosphere. Thereby, in addition to being able to perform processing in one film-forming apparatus, the remaining impurities between the first metal oxide layer 231a and the second metal oxide layer 231b can be suppressed.

[0093] Preferably, the second metal oxide layer 231b includes a region with higher crystallinity than the first metal oxide layer 231a. Thereby, the second metal oxide layer 231b can be a film with higher etching resistance than the first metal oxide layer 231a. Therefore, it is possible to prevent the second metal oxide layer 231b from disappearing due to etching when processing the conductive layer 222a and the conductive layer 222c. Therefore, it is possible to achieve as Figure 2A 、Figure 2B A transistor with the channel etching structure shown. Furthermore, by using a film with high crystallinity for the second metal oxide layer 231b on the back channel side of the transistor, impurities that may diffuse into the first metal oxide layer 231a on the gate 221 side can be reduced, so a highly reliable transistor can be achieved.

[0094] By using a film for the first metal oxide layer 231a that includes a region with lower crystallinity than the second metal oxide layer 231b, oxygen can easily diffuse in the first metal oxide layer 231a, and thus the ratio of oxygen vacancies in the first metal oxide layer 231a can be reduced. In particular, the first metal oxide layer 231a is closer to the gate 221 side and is the layer where a channel is mainly likely to be formed. By using the above-mentioned film, a highly reliable transistor can be achieved.

[0095] The first metal oxide layer 231a and the second metal oxide layer 231b can be formed separately, for example, by making the film-forming conditions different. For example, the flow rate of oxygen gas in the film-forming gas for the first metal oxide layer 231a and the second metal oxide layer 231b can be made different.

[0096] At this time, as the film-forming condition for the first metal oxide layer 231a, the ratio of the flow rate of oxygen gas in the total gas flow rate (also called the oxygen flow ratio) is set to be 0% or more and 30% or less, preferably 5% or more and 15% or less. By adopting the oxygen flow ratio within the above range, the crystallinity of the first metal oxide layer 231a can be reduced.

[0097] On the other hand, as the film-forming condition for the second metal oxide layer 231b, the oxygen flow ratio is set to be greater than 30% and 100% or less, preferably 50% or more and 100% or less, more preferably 70% or more and 100% or less. By adopting the oxygen flow ratio within the above range, the crystallinity of the second metal oxide layer 231b can be increased.

[0098] The substrate temperature when forming the first metal oxide layer 231a and the second metal oxide layer 231b is preferably 25°C (room temperature) or more and 200°C or less, more preferably room temperature or more and 130°C or less. By adopting the substrate temperature within the above range, when using a large-area glass substrate, bending or distortion of the substrate can be suppressed. Here, by making the substrate temperature the same when forming the first metal oxide layer 231a and the second metal oxide layer 231b, productivity can be improved. In addition, for example, when the substrate temperatures when forming the first metal oxide layer 231a and the second metal oxide layer 231b are different, by increasing the substrate temperature when forming the second metal oxide layer 231b, the crystallinity of the second metal oxide layer 231b can be further increased.

[0099] For example, preferably, a CAC-OS (Cloud-Aligned Composite oxide semiconductor) film is used as the first metal oxide layer 231a, and a CAAC-OS (c-axis-aligned crystalline oxide semiconductor) film is used to form the second metal oxide layer 231b.

[0100] The conductive layer for the gate 221 can also function as a scanning line. In other words, a single conductive layer can also function as both a scanning line and the gate 221. Additionally, the conductive layer for the conductive layer 222a can also function as a signal line. In other words, a single conductive layer can also function as both a signal line and the conductive layer 222a. The resistance of the conductive layer used as a scanning line or a signal line is preferably low enough. Therefore, the conductive layer used as a scanning line or a signal line is preferably formed of a metal, an alloy, or the like. The conductive layer used as a scanning line or a signal line can also be formed of a material having a function of blocking visible light.

[0101] Specifically, the resistivity of a conductive material that transmits visible light is sometimes higher than that of a conductive material that blocks visible light, such as copper or aluminum. Therefore, in order to prevent signal delay, the buses such as scanning lines and signal lines are preferably formed of a conductive material (metal material) having a low resistivity and blocking visible light. However, depending on the size of the pixel, the width of the bus, the thickness of the bus, etc., the bus can be formed of a conductive material that transmits visible light.

[0102] By using a conductive layer that blocks visible light for the gate 221, the light from the backlight can be prevented from irradiating the semiconductor layer 231. Thus, by overlapping the semiconductor layer 231 with a conductive layer that blocks visible light, the characteristic variation of the transistor caused by light can be suppressed. Thereby, the reliability of the transistor can be improved.

[0103] Since a light-shielding layer 132 is provided on the substrate 61 side of the semiconductor layer 231 and a gate 221 that blocks visible light is provided on the substrate 51 side of the semiconductor layer 231, the external light and the light from the backlight can be prevented from irradiating the semiconductor layer 231.

[0104] Here, Figure 3B A modified example of the transistor 206 is shown. Figure 3BAn example is shown in which a part of the semiconductor layer 231 of the transistor 206 is located in the display region 68. In the case where silicon (typically amorphous silicon or low-temperature polycrystalline silicon, etc.) is used for the semiconductor layer of the transistor, since the semiconductor layer absorbs a part of visible light, it is difficult to extract light through the semiconductor layer. In addition, when impurities such as phosphorus and boron are contained in silicon, the light transmittance may be further reduced. Therefore, it is sometimes difficult to extract light through the low-resistance region formed in silicon. However, in one mode of the present invention, both the oxide semiconductor (OS) and the oxide conductor (OC) are transparent to visible light, so the aperture ratio of the pixel or sub-pixel can be increased.

[0105] The transistor 206 is covered with the insulating layer 212, the insulating layer 214, and the insulating layer 215. In addition, the insulating layer 212 and the insulating layer 214 can also be regarded as constituent elements of the transistor 206. The transistor is preferably covered with an insulating layer having an effect of suppressing the diffusion of impurities into the semiconductor constituting the transistor. The insulating layer 215 can be used as a planarization layer.

[0106] Both the insulating layer 212 and the insulating layer 213 preferably include an excess oxygen region. When the insulating layer 212 and the insulating layer 213 include an excess oxygen region, excess oxygen can be supplied to the semiconductor layer 231. Since the oxygen defects that may be formed in the semiconductor layer 231 can be filled with the excess oxygen, a highly reliable transistor can be provided.

[0107] As the insulating layer 212, an oxide insulating film such as a silicon oxide film or a silicon oxynitride film formed in an oxygen-containing atmosphere is preferably used. Furthermore, as the insulating layer 214, an insulating film such as a silicon nitride film that does not easily allow oxygen to diffuse and permeate is preferably formed on the silicon oxide film or the silicon oxynitride film. The oxide insulating film formed in an oxygen-containing atmosphere can be an insulating film that easily releases a large amount of oxygen by heating. By performing a heat treatment in a state where such an oxygen-releasing oxide insulating film and an insulating film that does not easily allow oxygen to diffuse and permeate are laminated, oxygen can be supplied to the semiconductor layer 231. As a result, the oxygen defects in the semiconductor layer 231 and the defects at the interface between the semiconductor layer 231 and the insulating layer 212 can be filled, and the defect state density can be reduced. Thereby, a display device with extremely high reliability can be realized.

[0108] A liquid crystal element 40 is provided in the display region 68. The liquid crystal element 40 is a liquid crystal element adopting the FFS (Fringe Field Switching) mode.

[0109] The liquid crystal element 40 includes a pixel electrode 111, a common electrode 112, and a liquid crystal layer 113. By generating an electric field between the pixel electrode 111 and the common electrode 112, the orientation of the liquid crystal layer 113 can be controlled. The liquid crystal layer 113 is located between the alignment film 133a and the alignment film 133b.

[0110] The common electrode 112 may have a comb-shaped top surface shape (also referred to as a planar shape) or a top surface shape formed with slits. Figure 2A and Figure 3A An example is shown in which an opening of a common electrode 112 is formed in the display region 68 of one sub-pixel. One or more openings may be formed in the common electrode 112. As the display device becomes higher in resolution, the area of the display region 68 of one sub-pixel becomes smaller. Therefore, the number of openings formed in the common electrode 112 is not limited to multiple, and may also be one. That is, in a high-resolution display device, since the area of a pixel (sub-pixel) is small, even if there is only one opening in the common electrode 112, an electric field required for aligning liquid crystal can be generated over the entire display region of the sub-pixel.

[0111] An insulating layer 220 is provided between the pixel electrode 111 and the common electrode 112. The pixel electrode 111 has a portion overlapping the common electrode 112 with the insulating layer 220 therebetween. In addition, in the region where the pixel electrode 111 overlaps with the coloring layer 131, there is a portion where the common electrode 112 is not provided on the pixel electrode 111.

[0112] Preferably, an alignment film in contact with the liquid crystal layer 113 is provided. 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 common electrode 112 and the insulating layer 220 and the liquid crystal layer 113, and the alignment film 133b is located between the protective layer 121 and the liquid crystal layer 113.

[0113] As liquid crystal materials, there are positive liquid crystal materials having a positive dielectric anisotropy (Δε) and negative liquid crystal materials having a negative anisotropy. In one embodiment of the present invention, any of positive and negative materials can be used, and an appropriate liquid crystal material can be used according to the adopted mode and design.

[0114] In one embodiment of the present invention, it is preferable to use a negative liquid crystal material. When using a negative liquid crystal material, the influence of the flexoelectric effect can be suppressed, and the polarity of the voltage applied to the liquid crystal layer hardly affects the transmittance. Therefore, it is possible to suppress a user of the display device from seeing flicker. The flexoelectric effect is a phenomenon mainly caused by the molecular shape and polarization due to alignment distortion. In a negative liquid crystal material, alignment distortion such as splay deformation or bend deformation is not easily generated.

[0115] Here, a liquid crystal element 40 using the FFS mode is employed, but one aspect of the present invention is not limited thereto, and liquid crystal elements using various modes can be adopted. For example, a liquid crystal element using a VA (Vertical Alignment) mode, a TN (Twisted Nematic) mode, an IPS (In-Plane-Switching) mode, an ASM (Axially Symmetric Aligned Micro-cell) mode, an OCB (Optically Compensated Birefringence) mode, an FLC (Ferroelectric Liquid Crystal) mode, an AFLC (AntiFerroelectric Liquid Crystal) mode, an ECB (Electrically Controlled Birefringence) mode, a VA-IPS (Vertical Alignment In-Plane-Switching) mode, a guest-host mode, etc. can be used.

[0116] In addition, a normally black liquid crystal display device can be used for the display device 100A, for example, a transmissive liquid crystal display device using a vertical alignment (VA) mode. As the vertical alignment mode, an MVA (Multi-Domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, an ASV (Advanced Super View) mode, etc. can be used.

[0117] A liquid crystal element is an element that controls the transmission or non-transmission of light by utilizing the optical modulation effect of liquid crystal. The optical modulation effect of liquid crystal is controlled by an electric field (horizontal electric field, vertical electric field, or inclined direction electric field) applied to the liquid crystal. As the liquid crystal used for the liquid crystal element, thermotropic liquid crystal, low molecular liquid crystal, high molecular liquid crystal, polymer dispersed liquid crystal (PDLC: Polymer Dispersed Liquid Crystal), ferroelectric liquid crystal, antiferroelectric liquid crystal, etc. can be used. These liquid crystal materials exhibit a cholesteric phase, a smectic phase, a cubic phase, a chiral nematic phase, an isotropic phase, etc. according to conditions.

[0118] In addition, in the case of adopting a horizontal electric field method, a liquid crystal exhibiting a blue phase without using an alignment film can also be used. The blue phase is a kind of liquid crystal phase, which refers to the phase that appears just before the cholesteric liquid crystal changes from the cholesteric phase to the homogeneous phase when the temperature of the cholesteric liquid crystal is increased. Since the blue phase appears only in a narrow temperature range, a liquid crystal composition in which more than 5 wt% of a chiral reagent is mixed is used for the liquid crystal layer 113 to widen the temperature range. Since the liquid crystal composition containing the liquid crystal exhibiting the blue phase and the chiral reagent has a fast response speed and is optically isotropic. In addition, the liquid crystal composition containing the liquid crystal exhibiting the blue phase and the chiral reagent does not require an alignment treatment and has little viewing angle dependence. In addition, since there is no need to provide an alignment film, there is no need for a rubbing treatment, so electrostatic damage caused by the rubbing treatment can be prevented, and defects and breakages of the liquid crystal display device in the manufacturing process can be reduced.

[0119] Since the display device 100A is a transmissive liquid crystal display device, a conductive material that transmits visible light is used for the pixel electrode 111 and the common electrode 112. In addition, a conductive material that transmits visible light is used for one or more of the conductive layers included in the transistor 206. Thereby, at least a part of the transistor 206 can be provided in the display area 68. In Figure 2A and Figure 2B an example of using a semiconductor material that transmits visible light for the conductive layer 222c is shown.

[0120] As the conductive material that transmits visible light, for example, a material containing one or more selected from indium (In), zinc (Zn), and tin (Sn) is preferably used. Specifically, 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, zinc oxide containing gallium, etc. can be cited. In addition, a film containing graphene can also be used. The film containing graphene can be formed, for example, by reducing a film containing graphene oxide.

[0121] Preferably, an oxide conductive layer is used for one or more of the conductive layer 222c, the pixel electrode 111, and the common electrode 112. The oxide conductive layer preferably contains one or more metal elements contained in the semiconductor layer 231 of the transistor 206. For example, the conductive layer 222c preferably contains indium, and more preferably an oxide film containing In, M (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn, or Hf), and Zn. Similarly, the pixel electrode 111 and the common electrode 112 preferably both contain indium, and more preferably an oxide film containing In, M (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn, or Hf), and Zn.

[0122] In addition, an oxide semiconductor may be used to form one or more of the conductive layer 222c, the pixel electrode 111, and the common electrode 112. By using an oxide semiconductor containing the same metal element for two or more of the layers constituting the display device, manufacturing apparatuses (e.g., a film forming apparatus, a processing apparatus, etc.) can be used in common in two or more processes, so that the manufacturing cost can be suppressed.

[0123] An oxide semiconductor is a semiconductor material whose resistance can be controlled by at least one of oxygen deficiency in the film and the concentration of impurities such as hydrogen and water in the film. Accordingly, by selecting a process for increasing at least one of oxygen deficiency and impurity concentration in the oxide semiconductor layer or a process for decreasing at least one of oxygen deficiency and impurity concentration, the resistivity of the oxide conductive layer can be controlled.

[0124] In addition, as such, an oxide conductive layer formed using an oxide semiconductor layer may also be referred to as an oxide semiconductor layer having a high carrier density and a low resistance, an oxide semiconductor layer having conductivity, or an oxide semiconductor layer having high conductivity.

[0125] In addition, by forming the oxide semiconductor layer and the oxide conductive layer using the same metal element, the manufacturing cost can be reduced. For example, by using a metal oxide target composed of the same metal, the manufacturing cost can be reduced. In addition, by using a metal oxide target having the same metal composition, an etching gas or an etching liquid used for processing the oxide semiconductor layer can also be used in common. However, even if the oxide semiconductor layer and the oxide conductive layer have the same metal element, their compositions may sometimes be different from each other. For example, in the manufacturing process of the display device, the metal element in the film may sometimes be detached and the metal composition may change.

[0126] For example, in the case where a silicon nitride film containing hydrogen is used for the insulating layer 212 and an oxide semiconductor is used for the conductive layer 222c, the conductivity of the oxide semiconductor can be increased due to the hydrogen supplied from the insulating layer 212. For example, in the case where 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 increased due to the hydrogen supplied from the insulating layer 220.

[0127] On the side of the display device 100A closer to the substrate 61 than the liquid crystal layer 113, a coloring layer 131 and a light shielding layer 132 are provided. The coloring layer 131 is located at least in a portion overlapping with the display region 68 of the sub-pixel. In a non-display region 66 included in the pixel (sub-pixel), a light shielding layer 132 is provided. The light shielding layer 132 overlaps at least a part of the transistor 206.

[0128] Preferably, a protective layer 121 is provided between the coloring layer 131 and the light-shielding layer 132 and the liquid crystal layer 113. The protective layer 121 can suppress impurities contained in the coloring layer 131 and the light-shielding layer 132 from diffusing into the liquid crystal layer 113.

[0129] The substrate 51 and the substrate 61 are bonded together using an adhesive layer 141. The liquid crystal layer 113 is sealed in the region surrounded by the substrate 51, the substrate 61, and the adhesive layer 141.

[0130] When the display device 100A is used as a transmissive liquid crystal display device, two polarizers are arranged with the display unit 62 interposed therebetween. Figure 2A The polarizer 130 on the side of the substrate 61 is shown. Light 45 from a backlight on the outside of the polarizer on the side of the substrate 51 enters 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 common electrode 112 to control the optical modulation of the light. That is, the intensity of the light emitted through the polarizer 130 can be controlled. In addition, since light outside the specified wavelength range of the incident light is absorbed by the coloring layer 131, the emitted light becomes, for example, light presenting red, blue, or green.

[0131] In addition, in addition to the polarizer, for example, a circular polarizer can also be used. As the circular polarizer, for example, a polarizer formed by laminating a linear polarizer and a quarter-wave retardation plate can be used. The viewing angle dependence of the display of the display device can be reduced by the circular polarizer.

[0132] The drive circuit unit 64 includes a transistor 201. Figure 2B An enlarged view of the transistor 201 is shown.

[0133] The transistor 201 includes a gate 221, an insulating layer 213, a semiconductor layer 231, a conductive layer 222a, and a conductive layer 222b. One of the conductive layer 222a and the conductive layer 222b is used as the source electrode, and the other is used as the drain electrode. The conductive layer 222a and the conductive layer 222b are both electrically connected to the semiconductor layer 231.

[0134] As Figure 2B shown, the semiconductor layer 231 includes a first metal oxide layer 231a and a second metal oxide layer 231b on the first metal oxide layer 231a. Details of the semiconductor layer 231 can be referred to the description of the transistor 206.

[0135] The transistor provided in the drive circuit unit 64 may not have the function of transmitting visible light. Therefore, the conductive layer 222a and the conductive layer 222b can be formed using the same process and the same material (preferably a material with low resistivity such as metal).

[0136] In the connection portion 204, the wiring 65 and the conductive layer 251 are connected to each other, and the conductive layer 251 and the connection body 242 are connected to each other. 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 connection body 242. By adopting the above structure, signals and power can be supplied from the FPC 72 to the wiring 65.

[0137] The wiring 65 can be formed of the same material and by the same process as the conductive layers 222a and 222b included in the transistor 201 and the conductive layer 222a included in the transistor 206. The conductive layer 251 can be formed of the same material and by the same process as the pixel electrode 111 included in the liquid crystal element 40. Thus, when the conductive layers constituting the connection portion 204 are manufactured of the same material and by the same process as the conductive layers for the display portion 62 or the drive circuit portion 64, an increase in the number of processes can be suppressed, which is preferable.

[0138] The transistors 201 and 206 may have the same structure or different structures. That is to say, the transistors included in the drive circuit portion 64 and the transistors included in the display portion 62 may also have the same structure or different structures. In addition, the drive circuit portion 64 may include transistors having a plurality of structures, and the display portion 62 may also include transistors having a plurality of structures. For example, preferably, a transistor having a structure in which two gates are electrically connected is used as one or more of the shift register circuit, buffer circuit, and protection circuit included in the scan line drive circuit.

[0139] [Structural example of sub-pixel]

[0140] Figure 4A and Figure 4B are top views of sub-pixels according to one embodiment of the present invention. Figure 5A and Figure 5B are top views of sub-pixels for comparison.

[0141] Although some parts have been described, first, the characteristics of the pixel (sub-pixel) according to one embodiment of the present invention will be described.

[0142] Pixels are composed of transistors, capacitors, scan lines, signal lines, etc. In many cases, the above components are formed of a metal film with low resistivity. Since the metal film does not transmit light, the portions formed of the metal film are excluded from the display area, and as a result, the aperture ratio of the pixel becomes low. In particular, as the resolution increases, the aperture ratio decreases significantly. In a liquid crystal display device, when the aperture ratio decreases, in order to increase the brightness and contrast, it is necessary to increase the amount of light from the backlight, resulting in an increase in the power consumption of the backlight.

[0143] Thus, in one aspect of the present invention, one or more of the transistor, capacitor, wiring, and contact portion provided in the pixel have a structure that allows visible light to pass through. Specifically, the above-described components are formed using a material that allows visible light to pass through, such as an oxide semiconductor or an oxide conductor. Since the components provided in the pixel allow visible light to pass through, it is possible to increase the aperture ratio and reduce the power consumption of the backlight. In addition, in order to achieve low resistance, the scan line, signal line, power supply line, and peripheral circuit are formed using a metal material. Thus, preferably, each conductive film is formed using a different material according to its function.

[0144] By using a material that allows visible light to pass through, such as an oxide semiconductor or an oxide conductor, transistors having various structures can be manufactured. Different from silicon, an oxide semiconductor has the characteristic of being transparent to visible light even when doped with impurities to achieve low resistance.

[0145] Figures 4A to 5B It is a top view of a sub-pixel of a liquid crystal element including a vertical electric field mode such as TN mode or VA mode. Figure 4A and Figure 4B It is a top view of a sub-pixel adopting one aspect of the present invention. Figure 5A and Figure 5B It is a top view of a sub-pixel for comparison.

[0146] Figure 4A and Figure 5A It is a top view of the stacked structure from the gate 223 to the pixel electrode 111 in the sub-pixel as seen from the pixel electrode 111 side. Figure 4A and Figure 5A The display area 68 of the sub-pixel is indicated by a thick dashed box. Figure 4B and Figure 5B are respectively from Figure 4A and Figure 5A The top view of the stacked structure excluding the pixel electrode 111.

[0147] Figures 4A to 5B The transistor shown has gates provided above and below the channel.

[0148] The gate 221 is electrically connected to the gate 223. Compared with other transistors, a transistor having such a structure with two electrically connected gates can improve the field-effect mobility and increase the on-state current. As a result, a circuit capable of operating at high speed can be manufactured. Furthermore, the occupied area of the circuit portion can be reduced. By using a transistor with a large on-state current, even when the number of wirings increases due to the enlargement or high resolution of the display device, the signal delay of each wiring can be reduced, and display unevenness can be suppressed. In addition, by adopting such a structure, a highly reliable transistor can be realized.

[0149] InFigures 4A to 5B Among them, it can also be said that a conductive layer has the functions of the scanning line 228 and the gate 223. Among the gates 221 and 223, the one with lower resistance is preferably the conductive layer that is also used as the scanning line. The resistance of the conductive layer used as the scanning line 228 is preferably low enough. Therefore, the conductive layer used as the scanning line 228 is preferably formed of a metal, an alloy, etc. The conductive layer used as the scanning line 228 can also be formed of a material having a function of shielding visible light.

[0150] In Figures 4A to 5B Among them, it can also be said that a conductive layer has the functions of the signal line 229 and the conductive layer 222a. The resistance of the conductive layer used as the signal line 229 is preferably low enough. Therefore, the conductive layer used as the signal line 229 is preferably formed of a metal, an alloy, etc. The conductive layer used as the signal line 229 can also be formed of a material having a function of shielding visible light.

[0151] Both the gates 221 and 223 can be formed of a single layer of one of a metal material and an oxide conductor or a laminate of the two. For example, an oxide conductor can be used for one of the gates 221 and 223, and a metal material can be used for the other.

[0152] The transistor can have the following structure: an oxide semiconductor layer is used as the semiconductor layer, and an oxide conductive layer is used as at least one of the gates 221 and 223. At this time, it is preferable to use an oxide semiconductor to form the oxide semiconductor layer and the oxide conductive layer.

[0153] Figures 4A to 5B An example in which a capacitor line 244 is provided in the sub-pixel is shown. The capacitor line 244 is electrically connected to a conductive layer formed of the same material and in the same process as the conductive layer (for example, the gate 221) included in the transistor. In Figure 4A and Figure 4B Among them, a conductive layer 222c that transmits visible light is provided so as to overlap with the capacitor line 244. In Figure 5A and Figure 5B Among them, a conductive layer 222b that shields visible light is provided so as to overlap with the capacitor line 244. In Figure 4A and Figure 4B Among them, the conductive layer 222c is connected to the pixel electrode 111. In Figure 5A and Figure 5B Among them, the conductive layer 222b is connected to the pixel electrode 111.

[0154] In Figure 4A and Figure 4B In the structure shown, at least a part of the capacitor and the contact portion of the conductive layer 222c with the pixel electrode 111 can be provided in the display area 68. Therefore, compared with Figure 5A and Figure 5BCompared with the structure shown, Figure 4A and Figure 4B the structure shown can improve the aperture ratio of sub-pixels. In addition, the power consumption of the display device can be reduced.

[0155] In one aspect of the present invention, by disposing the contact portion of the pixel electrode 111 with the transistor and the capacitor in the display area 68, the aperture ratio can be increased by more than 10% or more than 20%. Thereby, the power consumption of the backlight can be reduced by more than 10% or more than 20%.

[0156] Next, the change amounts of the aperture ratio and the power consumption of the backlight when changing the structure shown by Figure 5A and Figure 5B to the structure shown by Figure 4A and Figure 4B are estimated.

[0157] Here, a display for a large TV is assumed, and the case where the sub-pixel layout shown by Figure 4A and Figure 4B and Figures 5A to 5B is applied to a TN-mode liquid crystal display device with a resolution of 136 ppi, a diagonal size of the display area of 65 inches, and a definition of 8K is described.

[0158] The size of the sub-pixel is 62.5 μm × 187.5 μm. The liquid crystal element adopts a vertical electric field mode, and the storage capacitor can be formed between the gate wiring and the source wiring or the drain wiring. In addition, since 120 Hz driving is assumed, two signal lines are provided in one sub-pixel. In addition, the transistor has a BGTC-type channel etching structure.

[0159] Figure 5A The aperture ratio of the pixel layout shown is 37.3%. Figure 4A The aperture ratio of the pixel layout shown is 47.1%. By making the contact portion of the storage capacitor and the transistor with the pixel electrode have a structure that allows visible light to pass through, the aperture ratio can be increased by 1.26 times, and it is estimated that the power consumption of the backlight can be reduced by about 21%.

[0160] [Materials]

[0161] Next, the details of the materials and the like of the respective components that can be used in the display device of the present embodiment are described. Note that the description of the components that have already been described may sometimes be omitted. In addition, the following materials can also be appropriately used for the display device, the touch screen, and their components shown later.

[0162] 《Substrates 51, 61》

[0163] There are no particular limitations on the material of the substrate included in the display device according to one embodiment of the present invention, and various substrates can be used. For example, a glass substrate, a quartz substrate, a sapphire substrate, a semiconductor substrate, a ceramic substrate, a metal substrate, or a plastic substrate can be used.

[0164] By using a thin substrate, the weight reduction and thinning of the display device can be achieved. Furthermore, by using a substrate whose thickness allows it to have flexibility, a flexible display device can be achieved.

[0165] The display device according to one embodiment of the present invention is manufactured by forming transistors and the like on a manufacturing substrate and then transferring the transistors and the like to another substrate. By using the manufacturing substrate, transistors with good characteristics can be formed, transistors with low power consumption can be formed, a display device that is not easily damaged can be manufactured, heat resistance can be imparted to the display device, and the weight reduction or thinning of the display device can be achieved. The substrate to which the transistors are transferred is not limited to a substrate capable of forming transistors. For example, a paper substrate, a cellophane substrate, a stone substrate, a wood substrate, a cloth substrate (including natural fibers (silk, cotton, linen), synthetic fibers (nylon, polyurethane, polyester), or regenerated fibers (acetate fiber, cuprammonium fiber, rayon, recycled polyester), etc.), a leather substrate, or a rubber substrate can be used.

[0166] "Transistors 201, 206"

[0167] The transistors included in the display device according to one embodiment of the present invention have either a top-gate type or a bottom-gate type structure. In addition, gate electrodes can be provided above and below the channel. The semiconductor material used for the transistors is not limited to this. For example, an oxide semiconductor, silicon, germanium, etc. can be cited.

[0168] There are no particular limitations on the crystallinity of the semiconductor material used for the transistors, and an amorphous semiconductor or a crystalline semiconductor (microcrystalline semiconductor, polycrystalline semiconductor, single-crystalline semiconductor, or a semiconductor having a crystalline region in a part thereof) can be used. When a crystalline semiconductor is used, deterioration of the transistor characteristics can be suppressed, so it is preferable.

[0169] For example, a Group 14 element, a compound semiconductor, or an oxide semiconductor can be used for the semiconductor layer. Typically, a semiconductor containing silicon, a semiconductor containing gallium arsenide, or an indium-containing oxide semiconductor, etc. can be used for the semiconductor layer.

[0170] It is preferable to use an oxide semiconductor for the semiconductor forming the channel of the transistor. In particular, it is preferable to use an oxide semiconductor having a larger bandgap than silicon. By using a semiconductor material having a wider bandgap and a smaller carrier density than silicon as the semiconductor included in the semiconductor layer, the current (off-state current) in the off-state of the transistor can be reduced, so it is preferable.

[0171] The oxide semiconductor can be referred to the above description and the description of Embodiment 4 etc.

[0172] By using the oxide semiconductor, a transistor with suppressed electrical property variations and high reliability can be realized.

[0173] In addition, since its off-state current is low, the charge stored in the capacitor through the transistor can be maintained for a long period. By using such a transistor for a pixel, the driving circuit can be stopped while maintaining the gray scale of the displayed image. As a result, a display device with extremely low power consumption can be realized.

[0174] Transistors 201 and 206 preferably include an oxide semiconductor layer that is highly purified and has suppressed formation of oxygen defects. Thereby, the off-state current of the transistor can be reduced. Therefore, the holding time of an electrical signal such as an image signal can be extended, and the writing interval can also be extended in the on state. Therefore, the frequency of the refresh operation can be reduced, and the effect of suppressing power consumption can be exerted.

[0175] In addition, in transistors 201 and 206, a high field-effect mobility can be obtained, so high-speed driving can be performed. By using such a transistor capable of high-speed driving for a display device, transistors for a display portion and transistors for a driving circuit portion can be formed on the same substrate. That is, since a semiconductor device formed of a silicon wafer etc. does not need to be separately used as a driving circuit, the number of components of the display device can be reduced. In addition, by also using a transistor capable of high-speed driving in the display portion, a high-quality image can be provided.

[0176] 《Insulating Layer》

[0177] As the insulating material that can be used for each insulating layer, protective layer, spacer, etc. included in the display device, an organic insulating material or an inorganic insulating material can be used. As the organic insulating material, for example, acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyamide-imide resin, silicone resin, benzocyclobutene resin, phenolic resin, etc. can be cited. As the inorganic insulating layer, silicon oxide film, silicon oxynitride film, silicon nitride oxide film, silicon nitride film, aluminum oxide film, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, and neodymium oxide film, etc. can be cited.

[0178] 《Conductive Layer》

[0179] In addition to the gate, source, and drain of a transistor, as the conductive layers such as various wirings and electrodes included in a display device, a single-layer structure or a laminated structure of an alloy mainly composed of metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten can be used. For example, a two-layer structure in which a titanium film is laminated on an aluminum film, a two-layer structure in which a titanium film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a molybdenum film, a two-layer structure in which a copper film is laminated on an alloy film containing molybdenum and tungsten, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a three-layer structure in which an aluminum film or a copper film is laminated on a titanium film or a titanium nitride film and then a titanium film or a titanium nitride film is formed thereon, a three-layer structure in which an aluminum film or a copper film is laminated on a molybdenum film or a molybdenum nitride film and then a molybdenum film or a molybdenum nitride film is formed thereon, etc. can be cited. For example, when the conductive layer has a three-layer structure, preferably, as the first layer and the third layer, a film formed of titanium, titanium nitride, molybdenum, tungsten, an alloy containing molybdenum and tungsten, an alloy containing molybdenum and zirconium, or molybdenum nitride is formed, and as the second layer, a film formed of a low-resistance material such as copper, aluminum, gold, silver, or an alloy of copper and manganese is formed. In addition, a light-transmissive conductive material 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, or ITSO can also be used.

[0180] In addition, an oxide conductive layer can also be formed by suppressing the resistivity of an oxide semiconductor.

[0181] 《Adhesive layer 141》

[0182] As the adhesive layer 141, a curable resin such as a thermosetting resin, a photocurable resin, or a two-component curable resin can be used. For example, an acrylic resin, a polyurethane resin, an epoxy resin, or a silicone resin can be used.

[0183] 《Connector 242》

[0184] As the connector 242, for example, an anisotropic conductive film (ACF: Anisotropic Conductive Film) or an anisotropic conductive paste (ACP: Anisotropic Conductive Paste) can be used.

[0185] 《Coloring layer 131》

[0186] The coloring layer 131 is a colored layer that transmits light in a specified wavelength range. As the material that can be used for the coloring layer 131, a metal material, a resin material, a resin material containing a pigment or a dye, etc. can be cited.

[0187] 《Light-shielding layer 132》

[0188] For example, the light-shielding layer 132 is disposed between adjacent color filter layers 131 of different colors. For example, a black matrix formed of a metal material or a resin material containing a pigment or a dye can be used as the light-shielding layer 132. In addition, by disposing the light-shielding layer 132 in a region outside the display unit 62 such as the driving circuit unit 64, light leakage caused by waveguide light or the like can be suppressed, which is preferable.

[0189] The thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can all be formed by sputtering, chemical vapor deposition (CVD: Chemical Vapor Deposition), vacuum evaporation, pulsed laser deposition (PLD: Pulsed Laser Deposition), atomic layer deposition (ALD: Atomic Layer Deposition), etc. As an example of the CVD method, plasma-enhanced chemical vapor deposition (PECVD) and thermal CVD can also be cited. As an example of the thermal CVD method, metal organic chemical vapor deposition (MOCVD) can be cited.

[0190] The thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can all be formed by spin coating, dipping, spraying, inkjet printing, dispenser method, screen printing, offset printing, doctor knife method, slot coating method, roll coating method, curtain coating method, knife-over-edge coating method, etc.

[0191] When processing the thin films constituting the display device, photolithography or the like can be used. In addition, an island-shaped thin film can be formed by a film formation method using a masking mask. In addition, the thin film can be processed by nanoimprinting, sandblasting, lift-off, etc. In photolithography, there are the following methods: a method of forming a resist mask on the thin film to be processed, processing the thin film by etching or the like, and removing the resist mask; a method of exposing and developing after forming a photosensitive thin film to process the thin film into a desired shape.

[0192] In photolithography, examples of the light used for exposure include i-line (wavelength: 365 nm), g-line (wavelength: 436 nm), h-line (wavelength: 405 nm), or light obtained by mixing these lights. Additionally, ultraviolet light, KrF laser, ArF laser, etc. can also be used. Further, immersion exposure technology can be utilized for exposure. Examples of the light used for exposure also include extreme ultraviolet light (EUV) and X-rays. Moreover, an electron beam can be used instead of the light for exposure. When using extreme ultraviolet light, X-rays, or an electron beam, extremely fine processing can be performed, so it is preferred. Additionally, when exposure is performed by scanning with an electron beam or the like, a photomask is not required.

[0193] As methods for etching a thin film, dry etching, wet etching, sandblasting, etc. can be utilized.

[0194] 〈2. Structural Example 2 of Display Device〉

[0195] Figures 6 to 8D Examples of a display device are shown respectively. Figure 6 It is a cross-sectional view of display device 100B. Figure 7 It is a cross-sectional view of display device 100C. Figure 8A It is a cross-sectional view of display device 100D. Note that the perspective views of display device 100B, display device 100C, and display device 100D are the same as those of Figure 1 the display device 100A shown, so the description thereof is omitted here.

[0196] Figure 6 The difference between the display device 100B shown and the above-mentioned display device 100A lies in the structure of the transistor.

[0197] Specifically, although the transistor of display device 100A includes one gate, the transistors 201 and 206 of display device 100B include two gates. As described above, the two gates are preferably electrically connected to each other. Thereby, the field-effect mobility of the transistor can be improved.

[0198] The structure other than this is the same as that of display device 100A, so the detailed description thereof is omitted.

[0199] Figure 7 The display device 100C shown is an example of a transmissive liquid crystal display device using a liquid crystal element of the longitudinal electric field type.

[0200] As Figure 7As shown, the display device 100C includes a substrate 51, a transistor 201, a transistor 206, a liquid crystal element 40, a capacitor 219, an orientation film 133a, an orientation film 133b, a connecting portion 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, etc.

[0201] The display unit 62 includes a transistor 206 , a liquid crystal element 40 , and a capacitor 219 .

[0202] The transistor 206 includes a gate 221 , an insulating layer 213 , a conductive layer 222 a , a conductive layer 222 c , and a semiconductor layer 231 .

[0203] The conductive layer 222 a and the conductive layer 222 c are both connected to the semiconductor layer 231 .

[0204] The liquid crystal element 40 is a liquid crystal element using a VA mode and includes a pixel electrode 111 , a common electrode 112 and a liquid crystal layer 113 . The liquid crystal layer 113 is located between the pixel electrode 111 and the common electrode 112 .

[0205] The pixel electrode 111 is electrically connected to the semiconductor layer 231 included in the transistor 206 through the conductive layer 222 c .

[0206] Capacitor 219 includes conductive layer 217 and conductive layer 218. Conductive layer 217 and conductive layer 218 overlap with each other via insulating layer 213.

[0207] Here, a conductive material that allows visible light to pass is used as the semiconductor layer 231, the conductive layer 222c, the conductive layer 217, and the conductive layer 218. The conductive layer 218 and the conductive layer 222c can be formed using the same process and the same material. Therefore, the contact portion between the pixel electrode 111 and the transistor 206 and the capacitor 219 can be arranged on the display region 68. As a result, the aperture ratio can be increased.

[0208] When the protective layer 121 has a planarization function, the common electrode 112 can be formed to be planar. Therefore, uneven thickness of the liquid crystal layer 113 can be suppressed.

[0209] right Figure 7 An example of a material for each layer of the transistor 206 and an example of a formation method are described below.

[0210] First, a conductive film that transmits visible light is formed as one electrode of the capacitor (conductive layer 217), and then a metal film such as a Cu film is formed by sputtering as a gate electrode 221. This metal film is also used as a scanning line. In addition, the gate wiring of a transistor of a peripheral circuit can be formed by using this metal film and the same process as the gate electrode 221.

[0211] Next, as the gate insulating layer, the insulating layer 213 is formed as a stack of a silicon nitride film and a silicon oxynitride film. Next, as the semiconductor layer 231, a stack of a CAC-OS film and a CAAC-OS film is formed by sputtering. By forming a CAAC-OS film with high chemical solution resistance and plasma resistance on the CAC-OS film, the semiconductor layer 231 is not easily damaged during the transistor manufacturing process. Next, as the conductive layer 222c serving as the source electrode or the drain electrode, an indium zinc oxide film is formed by sputtering. Both the semiconductor layer 231 and the conductive layer 222c can be formed by wet etching. When forming the conductive layer 222c, in order to improve the selectivity to prevent the semiconductor layer 231 from being etched, the conductive layer 222c is preferably formed using an etching solution different from the etching solution used when forming the semiconductor layer 231. In addition, this indium zinc oxide film can also be used to form the other electrode (conductive layer 218) of the capacitor in the same process as the conductive layer 222c.

[0212] Next, as the signal line and the conductive layer 222a, a metal film such as a Cu film is formed by sputtering. In addition, this metal film can also be used to form the source wiring and the drain wiring of the transistor in the peripheral circuit in the same process as the signal line and the conductive layer 222a.

[0213] Next, as the insulating layers 212 and 214 serving as the passivation film, a stack of a silicon oxynitride film and a silicon nitride film is formed using a PECVD apparatus. Then, an acrylic resin is applied as the insulating layer 215 having a planarization function to form an opening (contact hole). Then, an ITO film is formed as the pixel electrode 111.

[0214] In addition, as the gate electrode of the transistor included in the pixel, a metal film such as a Cu film formed as the scan line is preferably used. Thereby, light from the backlight can be suppressed from irradiating the channel formation region. In Figure 7 the contact portion between the transistor 206 and the pixel electrode 111 and the capacitor 219 can transmit visible light.

[0215] Figure 8A The display device 100D shown is different from the above-described display device 100C in the arrangement and shape of the pixel electrode 111 and the common electrode 112.

[0216] Both the pixel electrode 111 and the common electrode 112 can have a comb-tooth-shaped top surface shape (also referred to as a planar shape) or a top surface shape formed with a slit.

[0217] In Figure 8A the display device 100D shown, the pixel electrode 111 and the common electrode 112 are provided on the same plane.

[0218] In addition, when viewed from the top surface, the ends of the slits of one electrode may also be aligned with the ends of the slits of the other electrode. Figure 8B The cross-sectional view at this time is shown.

[0219] In addition, when viewed from the top surface, the pixel electrode 111 and the common electrode 112 may also have overlapping portions with each other. Figure 8C The cross-sectional view at this time is shown.

[0220] In addition, when viewed from the top surface, the display unit 62 may also have a portion where neither the pixel electrode 111 nor the common electrode 112 is provided. Figure 8D The cross-sectional view at this time is shown.

[0221] As described above, the display device according to one embodiment of the present invention can use transistors and liquid crystal elements of various shapes.

[0222] 〈3. Pixel arrangement example〉

[0223] Figure 9A and Figure 9B The pixel arrangement example is shown. Figure 9A and Figure 9B An example in which one pixel is composed of a red sub-pixel R, a green sub-pixel G, and a blue sub-pixel B is shown. In Figure 9A and Figure 9B A plurality of scan lines 81 extend in the x direction, a plurality of signal lines 82 extend in the y direction, and the scan lines 81 intersect the signal lines 82.

[0224] As Figure 9A shown within the double-dot dash frame of, the sub-pixel includes a transistor 206, a capacitor 34, and a liquid crystal element 40. The gate of the transistor 206 is electrically connected to the scan line 81. One of the source and drain of the transistor 206 is electrically connected to the signal line 82, and the other is electrically connected to one electrode of the capacitor 34 and one electrode of the liquid crystal element 40. The other electrode of the capacitor 34 and the other electrode of the liquid crystal element 40 are each supplied with a constant potential.

[0225] Figure 9A and Figure 9B An example of driving with source line inversion is shown. The polarities of signal A1 and signal A2 are the same. The polarities of signal B1 and signal B2 are the same. The polarities of signal A1 and signal B1 are different. The polarities of signal A2 and signal B2 are different.

[0226] As the display device becomes higher definition, the distance between sub-pixels becomes narrower. Therefore, for example, as Figure 9A shown within the dash frame of, near the signal line 82 of the sub-pixel to which signal A1 is input and to which signal B1 is input, the liquid crystal is likely to be affected by the potentials of both signal A1 and signal B1. As a result, poor alignment of the liquid crystal is likely to occur.

[0227] In Figure 9A , the direction in which a plurality of sub-pixels presenting the same color are arranged is the y-direction, which is substantially parallel to the extending direction of the signal line 82. As Figure 9A shown within the dotted-line frame of

[0228] In Figure 9B , the direction in which a plurality of sub-pixels presenting the same color are arranged is the x-direction, which intersects the extending direction of the signal line 82. As Figure 9B shown within the dotted-line frame of

[0229] As Figure 9B shown, when the side of the sub-pixel that is substantially parallel to the extending direction of the signal line 82 is the short side, compared with the case where this side is the long side (refer to Figure 9A ), the region where the alignment defect of the liquid crystal is likely to occur can be made narrower. As Figure 9B shown, when the region where the alignment defect of the liquid crystal is likely to occur is between sub-pixels presenting the same color, compared with the case where this region is between sub-pixels presenting different colors (refer to Figure 9A ), it is less likely for the user of the display device to notice the display defect. In one aspect of the present invention, the arrangement direction of the plurality of sub-pixels presenting the same color preferably intersects the extending direction of the signal line 82.

[0230] 〈4. Structural Example 3 of the Display Device〉

[0231] One aspect of the present invention can be used for a display device (also referred to as an input / output device or a touch screen) equipped with a touch sensor. The structures of the above-mentioned display devices can be used for the touch screen. In the present embodiment, an example of mounting the touch sensor in the display device 100A will be mainly described.

[0232] There is no particular limitation on the detection element (also referred to as a sensor element) included in the touch screen of one aspect of the present invention. Various sensors capable of detecting the approach or contact of a detection object such as a finger or a stylus can also be used as the detection element.

[0233] For example, as a sensor method, various methods such as capacitive, resistive film, surface acoustic wave, infrared, optical, and piezoresistive can be utilized.

[0234] In the present embodiment, a touch screen including a capacitive detection element will be described as an example.

[0235] As a capacitive type, there are a surface capacitive type, a projected capacitive type, etc. Further, as the projected capacitive type, there are a self-capacitive type, a mutual-capacitive type, etc. When the mutual-capacitive type is used, multi-point sensing can be performed simultaneously, so it is preferable.

[0236] The touch panel according to one embodiment of the present invention can adopt various structures such as a structure in which a separately formed display device and a detection element are bonded, and a structure in which electrodes constituting the detection element are provided on one or both of a substrate supporting the display element and a counter substrate.

[0237] Figure 10A and Figure 10B An example of the touch panel is shown. Figure 10A FIG. is a perspective view of a touch panel 350A according to one embodiment of the present invention. Figure 10B is to Figure 10A A perspective schematic view when expanded. Note that, for clarity, Figures 10A to 10B only typical components are shown. In Figure 10B the substrate 61 and the substrate 162 are shown only by their outlines in dashed lines.

[0238] The touch panel 350A has a structure in which a separately formed display device and a detection element are bonded.

[0239] The touch panel 350A includes an input device 375 and a display device 370 which are overlapped and arranged.

[0240] The input device 375 includes a substrate 162, electrodes 127, electrodes 128, a plurality of wirings 137, and a plurality of wirings 138. The FPC 72b is electrically connected to the plurality of wirings 137 and the plurality of wirings 138. The IC 73b is provided on the FPC 72b.

[0241] The display device 370 includes substrates 51 and 61 which are arranged to face each other. The display device 370 includes a display unit 62 and a drive circuit unit 64. Wirings 65 etc. are provided on the substrate 51. The FPC 72a is electrically connected to the wiring 65. The IC 73a is provided on the FPC 72a.

[0242] Signals and power are supplied from the wiring 65 to the display unit 62 and the drive circuit unit 64. The signals and power are input from the outside or from the IC 73a through the FPC 72a to the wiring 65.

[0243] As Figure 10A and Figure 10B shown in Figure 2A the display device 370 shown in

[0244] 〈5. Structural Example 4 of Display Device〉

[0245] Figure 11AAnd Figure 11B An example of a touch screen is shown. Figure 11A It is a perspective view of a touch screen 350B according to one aspect of the present invention. Figure 11B It is Figure 11A A perspective schematic view when unfolded. Note that, for clarity, Figure 11A and Figure 11B only typical components are shown. In Figure 11B the substrate 61 is shown only by a dashed line for its outline.

[0246] The touch screen 350B is an In-Cell type touch screen having a function of displaying an image and a function of a touch sensor.

[0247] The touch screen 350B has a structure in which electrodes and the like constituting a sensing element are provided only on the counter substrate. By adopting this structure, compared with a structure in which a separately manufactured display device and a sensing element are bonded, thinning or lightening of the touch screen can be achieved, or the number of components of the touch screen can be reduced.

[0248] In Figure 11A and Figure 11B the input device 376 is provided on the substrate 61. In addition, wirings 137 and 138 of the input device 376 are electrically connected to an FPC 72 provided on the display device 379. For example, in the connection portion 63, one of the wirings 137 (or the wiring 138) is electrically connected to a conductive layer provided on one side of the substrate 51 through a connection body.

[0249] By adopting the above structure, the FPC connected to the touch screen 350B can be arranged only on one side of one substrate (here, one side of the substrate 51). In addition, although a structure in which two or more FPCs are provided for the touch screen 350B can also be adopted, when, as Figure 11A and Figure 11B shown, a structure in which one FPC 72 is provided for the touch screen 350B and signals are supplied to both the display device 379 and the input device 376 by this FPC 72 is adopted, the structure can be simplified, so it is preferable. Compared with the case where the FPC is connected to both one side of the substrate 51 and one side of the substrate 61, the touch screen 350B can be easily mounted in an electronic device, and the number of components can be reduced.

[0250] The IC 73 can have a function of driving the input device 376. In addition, an IC for driving the input device 376 can also be provided separately on the FPC 72. In addition, an IC for driving the input device 376 can also be mounted on the substrate 51.

[0251] As the conductive layer included in the input device that overlaps with the display area 68, a material that allows visible light to pass through is used. Additionally, the conductive layer included in the input device may be disposed only in the non-display area 66. When adopting a structure in which the conductive layer included in the input device does not overlap with the display area 68, there is no limitation on the visible light transmittance of the material of the conductive layer included in the input device. As the conductive layer included in the input device, a material with low resistivity such as metal can be used. For example, as the wiring and electrodes of the touch sensor, a metal mesh is preferably used. Thereby, the resistance of the wiring and electrodes of the touch sensor can be reduced. In addition, it is suitable for the touch sensor of a large display device. Generally, metal is a material with a large reflectivity, but it can be made dark by oxidation treatment or the like. Thereby, even when viewed from the display surface side, the visibility degradation caused by external light reflection can be suppressed.

[0252] In addition, the wiring and the electrodes may also be a laminate of a metal layer and a layer with a low reflectivity (also referred to as a "dark layer"). As an example of the dark layer, there is a layer containing copper oxide, a layer containing copper chloride or tellurium chloride, etc. In addition, the dark layer can also be formed using metal fine particles such as Ag particles, Ag fibers, Cu particles, carbon nanotubes (CNT), nano-carbon particles such as graphene, and conductive polymers such as PEDOT, polyaniline, and polypyrrole.

[0253] In the display device of the present embodiment, since the transistor includes a region that allows visible light to pass through, the aperture ratio of the pixel can be increased. Thereby, the power consumption of the display device can be reduced.

[0254] The present embodiment can be appropriately combined with other embodiments. Additionally, in this specification, when multiple structural examples are shown in one embodiment, the structural examples can be appropriately combined.

[0255] Embodiment 2

[0256] In the present embodiment, with reference to Figures 12A to 12C the operating modes that the display device of one aspect of the present invention can perform will be described.

[0257] Hereinafter, a normal operating mode (Normal mode) that operates at a normal frame rate (typically 60 Hz or more and 240 Hz or less) and an idling stop (IDS) drive mode that operates at a low frame rate will be exemplified and described.

[0258] The IDS driving mode refers to a driving method in which the rewriting of image data is stopped after the writing process of image data. By extending the interval between the writing of image data and the next writing of image data, the power consumption required for the writing of image data during this period can be saved. The frame frequency of the IDS driving mode can be, for example, about 1 / 100 to 1 / 10 of the normal operating mode. A static image has the same video signal between consecutive frames. Therefore, the IDS driving mode is particularly effective when displaying static images. By using IDS driving to display images, power consumption can be reduced, image flicker can be suppressed, and eye fatigue can be reduced.

[0259] Figures 12A to 12C is a timing diagram of an image circuit and illustrates the normal driving mode and the IDS driving mode. In Figure 12A it shows the first display element 501 (here, a reflective liquid crystal element), and the pixel circuit 506 electrically connected to the first display element 501. In Figure 12A the pixel circuit 506 shown, it shows the signal line SL, the gate line GL, the transistor M1 connected to the signal line SL and the gate line GL, and the capacitor Cs connected to the transistor M1 LC .

[0260] The transistor M1 may become a leakage path for the data D 1 . Therefore, the smaller the off-state current of the transistor M1, the better. As the transistor M1, a transistor including a metal oxide in the semiconductor layer forming the channel is preferably used. When the metal oxide has at least one of an amplification function, a rectification function, and a switching function, the metal oxide can be referred to as a metal oxide semiconductor, or it can be referred to as an oxide semiconductor, abbreviated as OS. Hereinafter, as a typical example of a transistor, a transistor using an oxide semiconductor in the semiconductor layer forming the channel (also referred to as an "OS transistor") will be described. Compared with a transistor using polysilicon or the like, the leakage current (off-state current) of the OS transistor in the non-conducting state is extremely small. By adopting the OS transistor as the transistor M1, the charge supplied to the node ND1 can be maintained for a long period.

[0261] In Figure 12A the circuit diagram shown, the liquid crystal element LC is a leakage path for the data D 1 . Therefore, in order to perform IDS driving appropriately, it is preferable to set the resistivity of the liquid crystal element LC to 1.0×10 14 Ω·cm or more.

[0262] For example, an oxide containing In, Ga and Zn, an oxide containing In and Zn, etc. may be applied to the channel region of the OS transistor. The composition of the oxide containing In, Ga and Zn may be typically around In:Ga:Zn=4:2:4.1 [atomic ratio].

[0263] Figure 12B 1 is a timing chart showing waveforms of signals supplied to the signal line SL and the gate line GL in the normal drive mode. In the normal drive mode, the operation is performed at a normal frame frequency (for example, 60 Hz). Figure 12B Show period T 1 To T 3 In each frame period, a scanning signal is supplied to the gate line GL, and data D is written from the signal line SL to the node ND1. 1 work. Regardless of the period T 1 To T 3 Write the same data D 1 Whether writing different data or not, the above work is performed.

[0264] on the other hand, Figure 12C 1 is a timing chart showing the waveform of the signal supplied to the signal line SL and the gate line GL in the IDS driving mode. In the IDS driving, the operation is performed at a low frame rate (for example, 1 Hz). 1 Represents a frame period, where the period T W Indicates the data writing period, with period T RET Indicates the data retention period. In the IDS drive mode, during the period T W The gate line GL is supplied with a scanning signal, and the data D of the signal line SL is 1 Write pixel, during T RET The gate line GL is fixed to a low level voltage, so that the transistor M1 is in a non-conductive state to write the written data D 1 The low frame rate may be, for example, above 0.1 Hz and below 60 Hz.

[0265] This embodiment mode can be combined with other embodiment modes as appropriate.

[0266] Implementation 3

[0267] In this embodiment, an example of a method of driving a touch sensor is described with reference to the drawings.

[0268] <Examples of sensor sensing methods>

[0269] Figure 13A is a block diagram showing the structure of a mutual capacitance touch sensor. Figure 13Ashows a pulse voltage output circuit 551 and a current detection circuit 552. Additionally, in Figure 13A the electrodes 521 to which a pulse voltage is applied and the electrodes 522 for sensing current changes are shown by six wirings X1 to X6 and Y1 to Y6, respectively. Further, in Figure 13A a capacitance 553 formed by overlapping the electrode 521 and the electrode 522 is illustrated. Note that the functions of the electrode 521 and the electrode 522 can be interchanged with each other.

[0270] The pulse voltage output circuit 551 is a circuit for sequentially applying a pulse voltage to the wirings X1 to X6. By applying a pulse voltage to the wirings X1 to X6, an electric field is generated between the electrode 521 and the electrode 522 forming the capacitance 553. By utilizing the change in the mutual capacitance of the capacitance 553 due to shielding or the like in the electric field generated between the electrodes, the approach or contact of the sensing object can be detected.

[0271] The current detection circuit 552 is a circuit for detecting the current changes in the wirings Y1 to Y6 based on the change in the mutual capacitance of the capacitance 553. In the wirings Y1 to Y6, if there is no approach or contact of the sensing object, the detected current value does not change. On the other hand, when the mutual capacitance decreases due to the approach or contact of the detected sensing object, a change in the decrease of the current value is detected. Additionally, the current can be detected by an integration circuit or the like.

[0272] Alternatively, one or both of the pulse voltage output circuit 551 and the current detection circuit 552 can be formed on Figure 1 the substrate 51 or the substrate 61 shown, etc. For example, when forming the display unit 62 and the drive circuit unit 64, etc. at the same time, not only can the process be simplified, but also the number of components for driving the touch screen can be reduced, so it is preferable. Alternatively, one or both of the pulse voltage output circuit 551 and the current detection circuit 552 can be mounted in the IC 73.

[0273] In particular, when crystalline silicon such as polysilicon or single crystal silicon is used as the semiconductor layer for forming the channel in the transistor formed on the substrate 51, the circuit driving ability of the pulse voltage output circuit 551 or the current detection circuit 552, etc. is improved, thereby improving the sensitivity of the touch sensor.

[0274] Figure 13B shows Figure 13A the timing chart of the input / output waveforms in the mutual capacitance type touch sensor shown. In Figure 13B each row and column, the detection of the sensing object is performed during one frame period. Additionally, in Figure 13BIn this, two cases of not detecting (not touching) the sensing object and detecting (touching) the sensing object are shown. In addition, regarding the wirings of Y1 to Y6, waveforms of voltage values corresponding to the detected current values are shown.

[0275] A pulse voltage is sequentially applied to the wirings of X1 to X6, and the waveforms in the wirings of Y1 to Y6 change according to this pulse voltage. When there is no approach or contact of the sensing object, the waveforms of Y1 to Y6 change according to the change in the voltage of the wirings of X1 to X6. On the other hand, at the part where the sensing object approaches or contacts, the current value decreases, and thus the waveforms of the corresponding voltage values also change.

[0276] In this way, by detecting the change in the mutual capacitance, the approach or contact of the sensing object can be sensed.

[0277] <Example of the driving method of the display device>

[0278] Figure 14A It is a block diagram showing a structural example of the display device. Figure 14A It shows a display unit including a gate driving circuit GD (scan line driving circuit), a source driving circuit SD (signal line driving circuit), and a plurality of pixels pix. Note that in Figure 14A corresponding to the gate lines x_1 to x_m (m is a natural number) electrically connected to the gate driving circuit GD and the source lines y_1 to y_n (n is a natural number) electrically connected to the source driving circuit SD, each pixel pix is attached with symbols of (1, 1) to (n, m).

[0279] Figure 14B It is for Figure 14A the timing chart of the signals applied to the gate lines and source lines in the display device shown. In Figure 14B it shows the cases of rewriting the data signal and not rewriting the data signal during each frame period, respectively. Note that in Figure 14B the periods such as the flyback period are not considered.

[0280] In the case of rewriting the data signal during each frame period, a scan signal is sequentially applied to the gate lines x_1 to x_m. During the horizontal scan period 1H when the scan signal is at the H level, data signals D are applied to the source lines y_1 to y_n of each column.

[0281] In the case of not rewriting the data signal during each frame period, applying the scan signal to the gate lines x_1 to x_m is stopped. In addition, during the horizontal scan period 1H, applying the data signal to the source lines y_1 to y_n of each column is stopped.

[0282] A driving method that does not rewrite the data signal during each frame period is particularly effective in the case where an oxide semiconductor is used for the semiconductor layer forming the channel of the transistor in the pixel pix. Compared with a transistor using a semiconductor such as silicon, a transistor using an oxide semiconductor can reduce the off-state current to an extremely low level. Therefore, the data signal written in the previous period can be maintained without rewriting the data signal during each frame period. For example, the gray scale of the pixel can also be maintained for more than 1 second, preferably more than 5 seconds.

[0283] In addition, when polysilicon or the like is used for the semiconductor layer forming the channel of the transistor in the pixel pix, it is preferable to set the storage capacitor of the pixel to be large in advance. The larger the storage capacitor, the longer the gray scale of the pixel can be maintained. The size of the storage capacitor can be set according to the leakage current of the transistor or the display element electrically connected to the storage capacitor. For example, when the storage capacitor of each pixel is 5 fF or more and 5 pF or less, preferably 10 fF or more and 5 pF or less, and more preferably 20 fF or more and 1 pF or less, the data signal written in the previous period can be maintained without rewriting the data signal during each frame period. For example, the gray scale of the pixel can be maintained for several frames or dozens of frames.

[0284] <Example of driving method for display unit and touch sensor>

[0285] Figures 15A to 15D This is an example to illustrate the driving Figure 13A and Figure 13B the touch sensor described Figure 14A and Figure 14B the diagram of the operation during consecutive frame periods in the case of the display unit described for 1 sec. (1 second). In addition, Figure 15A It shows the case where one frame period of the display unit is set to 16.7 ms (frame frequency: 60 Hz), and one frame period of the touch sensor is set to 16.7 ms (frame frequency: 60 Hz).

[0286] In the display device according to one embodiment of the present invention, the operations of the display unit and the touch sensor are independent of each other, and the touch sensing period can be set in parallel with the display period. Therefore, as Figure 15A shown, one frame period of both the display unit and the touch sensor can be set to 16.7 ms (frame frequency: 60 Hz). In addition, the frame frequency of the touch sensor can be different from that of the display unit. For example, as Figure 15B shown, one frame period of the display unit can be set to 8.3 ms (frame frequency: 120 Hz), and one frame period of the touch sensor can be set to 16.7 ms (frame frequency: 60 Hz). In addition, although not shown, the frame frequency of the display unit can also be set to 33.3 ms (frame frequency: 30 Hz).

[0287] In addition, by adopting a structure in which the frame frequency of the display unit can be switched, and increasing the frame frequency (e.g., above 60 Hz or above 120 Hz) when displaying a moving image, and decreasing the frame frequency (e.g., below 60 Hz, below 30 Hz, or below 1 Hz) when displaying a still image, the power consumption of the display device can be reduced. Alternatively, the frame frequency of the touch sensor can be set to a switchable structure, and the frame frequency during standby can be made different from that when a touch is detected.

[0288] In addition, in the display device according to one aspect of the present invention, by not rewriting the data signal in the display unit and maintaining the data signal rewritten in the previous period, a frame period of the display unit can be set to a period longer than 16.7 ms. Therefore, as Figure 15C shown, a frame period of the display unit can be set to 1 sec. (frame frequency: 1 Hz), and a frame period of the touch sensor can be set to 16.7 ms (frame frequency: 60 Hz).

[0289] In addition, regarding the structure of not rewriting the data signal in the display unit and maintaining the data signal rewritten in the previous period, the IDS driving mode described above can be referred to. The IDS driving mode can also be a partial IDS driving mode in which the data signal is rewritten only in a specific area of the display unit. The partial IDS driving mode refers to the following mode: the data signal is rewritten only in a specific area of the display unit, and the data signal rewritten in the previous period is maintained in the other areas.

[0290] In addition, according to the driving method of the touch sensor shown in the present embodiment, when performing the Figure 15C shown driving, the driving of the touch sensor can be continuously performed. Therefore, as Figure 15D shown, when the approach or contact of the sensing object in the touch sensor is sensed, the data signal of the display unit can also be rewritten.

[0291] Here, if the data signal of the display unit is rewritten during the sensing period of the touch sensor, since the noise generated when rewriting the data signal is transmitted to the touch sensor, the sensitivity of the touch sensor may be decreased. Therefore, it is preferable that the rewriting of the data signal of the display unit and the sensing of the touch sensor are performed in different periods.

[0292] Figure 16A Examples of alternately performing the rewriting of the data signal of the display unit and the sensing of the touch sensor are shown. In addition, Figure 16B Examples of performing the sensing of the touch sensor once every two rewritings of the data signal of the display unit are shown. Note that it is not limited thereto, and the sensing of the touch sensor can also be performed once every three or more rewritings.

[0293] In addition, when an oxide semiconductor is used for the semiconductor layer forming the channel of the transistor in pixel pix, the off-state current can be reduced to an extremely low level, so that the rewrite frequency of data signals can be sufficiently reduced. Specifically, a sufficiently long stop period can be set between the rewrite of data signals and the next rewrite of data signals. The stop period can be, for example, 0.5 seconds or more, 1 second or more, or 5 seconds or more. The upper limit of the stop period is limited by the leakage current of the capacitor connected to the transistor, the display element, etc., and can be, for example, 1 minute or less, 10 minutes or less, 1 hour or less, or 1 day or less, etc.

[0294] Figure 16C An example of rewriting the data signal of the display unit at a frequency of once every 5 seconds is shown. In Figure 16C 's display unit, a stop period for stopping the rewrite operation is provided during the period from the rewrite of the data signal to the next rewrite operation of the data signal. During the stop period, the touch sensor can be driven at a frame frequency of i Hz (i is equal to or higher than the frame frequency of the display device, and here is 0.2 Hz or higher). Or, as Figure 16C shown, by sensing the touch sensor during the stop period and not sensing the touch sensor during the rewrite period of the data signal of the display unit, the sensitivity of the touch sensor can be improved, so it is preferable. In addition, as Figure 16D shown, by simultaneously rewriting the data signal of the display unit and sensing the touch sensor, the signals for driving can be simplified.

[0295] In addition, during the stop period when the rewrite operation of the data signal of the display unit is not performed, the supply of the data signal to the display unit can be stopped and the operation of one or both of the gate drive circuit GD and the source drive circuit SD can be stopped. Furthermore, the power supply to one or both of the gate drive circuit GD and the source drive circuit SD can also be stopped. Thereby, the noise can be further reduced and the sensitivity of the touch sensor can be further improved. In addition, the power consumption of the display device can be further reduced.

[0296] A display device according to one embodiment of the present invention has a structure in which a display unit and a touch sensor are sandwiched between two substrates. Therefore, the distance between the display unit and the touch sensor can be minimized. At this time, the noise during the driving of the display unit is likely to be transmitted to the touch sensor, which may reduce the sensitivity of the touch sensor. By using the driving method exemplified in this embodiment, a display device including a touch screen that simultaneously achieves thinning and high detection sensitivity can be obtained.

[0297] This embodiment can be appropriately combined with other embodiments.

[0298] Embodiment 4

[0299] In this embodiment, the metal oxide of the semiconductor layer of the transistor that can be used in one aspect of the present invention will be described. Note that when the metal oxide is used for the semiconductor layer of the transistor, the metal oxide may also be referred to as an oxide semiconductor.

[0300] Oxide semiconductors are classified into single-crystalline oxide semiconductors and non-single-crystalline oxide semiconductors. As non-single-crystalline oxide semiconductors, there are CAAC-OS (c-axis-aligned crystalline oxide semiconductor), polycrystalline oxide semiconductors, nc-OS (nanocrystalline oxide semiconductor), a-like OS (amorphous-like oxide semiconductor), and amorphous oxide semiconductors, etc.

[0301] As the semiconductor layer of the transistor disclosed in one aspect of the present invention, CAC-OS (Cloud-Aligned Composite oxide semiconductor) can also be used.

[0302] The semiconductor layer of the transistor disclosed in one aspect of the present invention can use the above non-single-crystalline oxide semiconductor or CAC-OS. In addition, as the non-single-crystalline oxide semiconductor, nc-OS or CAAC-OS is preferably used.

[0303] In one aspect of the present invention, CAC-OS is preferably used as the semiconductor layer of the transistor. By using CAC-OS, high electrical characteristics or high reliability can be imparted to the transistor.

[0304] Hereinafter, the details of CAC-OS will be described.

[0305] CAC-OS or CAC-metal oxide has a conductive function in a part of the material and an insulating function in another part of the material, and has a semiconductor function as a whole. In addition, when CAC-OS or CAC-metal oxide is used for the channel formation region of the transistor, the conductive function is a function that allows electrons (or holes) used as carriers to flow, and the insulating function is a function that does not allow electrons used as carriers to flow. Through the complementary action of the conductive function and the insulating function, CAC-OS or CAC-metal oxide can have a switching function (on / off function). By separating each function in CAC-OS or CAC-metal oxide, each function can be maximized.

[0306] In addition, CAC-OS or CAC-metal oxide includes a conductive region and an insulating region. The conductive region has the function of the above-mentioned conductivity, and the insulating region has the function of the above-mentioned insulation. In addition, in the material, the conductive region and the insulating region are sometimes separated at a nanoparticle level. In addition, the conductive region and the insulating region are sometimes unevenly distributed in the material. In addition, sometimes the conductive region is observed to be fuzzy at its edge and connected in a cloud shape.

[0307] In CAC-OS or CAC-metal oxide, the conductive region and the insulating region may be dispersed in the material with a size of 0.5 nm to 10 nm, preferably 0.5 nm to 3 nm.

[0308] In addition, CAC-OS or CAC-metal oxide is composed of components with different band gaps. For example, CAC-OS or CAC-metal oxide is composed of a component with a wide gap caused by an insulating region and a component with a narrow gap caused by a conductive region. In this structure, when carriers are allowed to flow through, the carriers mainly flow through the component with the narrow gap. In addition, the component with a narrow gap complements the component with a wide gap, and the carriers flow through the component with the wide gap in conjunction with the component with the narrow gap. Therefore, when the above-mentioned CAC-OS or CAC-metal oxide is used in the channel formation region of a transistor, a high current driving force, that is, a large on-state current and a high field effect mobility can be obtained in the on-state of the transistor.

[0309] That is, CAC-OS or CAC-metal oxide may also be referred to as a matrix composite material (matrix composite) or a metal matrix composite material (metal matrix composite).

[0310] CAC-OS refers to, for example, a structure in which elements contained in a metal oxide are unevenly distributed, wherein the size of the material containing the unevenly distributed elements is greater than or equal to 0.5 nm and less than or equal to 10 nm, preferably greater than or equal to 1 nm and less than or equal to 2 nm, or a similar size. Note that in the following, a state in which one or more metal elements are unevenly distributed in a metal oxide and regions containing the metal elements are mixed is also referred to as a mosaic or patch shape, and the size of the region is greater than or equal to 0.5 nm and less than or equal to 10 nm, preferably greater than or equal to 1 nm and less than or equal to 2 nm, or a similar size.

[0311] The metal oxide preferably contains at least indium. In particular, it preferably contains indium and zinc. In addition, it may also contain one or more selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc.

[0312] For example, CAC-OS in In-Ga-Zn oxide (in CAC-OS, In-Ga-Zn oxide can be particularly referred to as CAC-IGZO) means that the material is divided into indium oxide (hereinafter referred to as InO X1 (X1 is a real number greater than 0)) or indium zinc oxide (hereinafter referred to as In X2 Zn Y2 O Z2 (X2, Y2, and Z2 are real numbers greater than 0)) and gallium oxide (hereinafter referred to as GaO X3 (X3 is a real number greater than 0)) or gallium zinc oxide (hereinafter referred to as Ga X4 Zn Y4 O Z4 (X4, Y4, and Z4 are real numbers greater than 0)) and the like to form a mosaic shape, and the mosaic-shaped InO X1 or In X2 Zn Y2 O Z2 is uniformly distributed in the film structure (hereinafter also referred to as cloud-like).

[0313] In other words, CAC-OS is a composite metal oxide having a structure in which regions mainly composed of GaO X3 and regions mainly composed of In X2 Zn Y2 O Z2 or InO X1 are mixed together. In this specification, for example, when the atomic ratio of In to element M in the first region is greater than the atomic ratio of In to element M in the second region, the In concentration in the first region is higher than that in the second region.

[0314] Note that IGZO is a general term and sometimes refers to a compound containing In, Ga, Zn, and O. As a typical example, there can be cited InGaO 3 (ZnO) m1 (m1 is a natural number) or In (1+x0) Ga (1-x0) O 3 (ZnO) m0 (-1 ≤ x0 ≤ 1, m0 is an arbitrary number) represents a crystalline compound.

[0315] The above crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC (c-axis aligned crystal) structure. The CAAC structure is a crystalline structure in which a plurality of nanocrystals of IGZO have c-axis orientation and are connected in a non-oriented manner on the a-b plane.

[0316] On the other hand, CAC-OS is related to the material composition of the metal oxide. CAC-OS refers to the following composition: in a material composition containing In, Ga, Zn, and O, nanoparticle-like regions mainly composed of Ga and nanoparticle-like regions mainly composed of In are observed to be randomly dispersed in a mosaic pattern in some parts. Therefore, in CAC-OS, the crystal structure is a secondary factor.

[0317] CAC-OS does not include a stacked structure of two or more films with different compositions. For example, it does not include a structure composed of two layers of a film mainly composed of In and a film mainly composed of Ga.

[0318] Note that sometimes no clear boundary can be observed between the region mainly composed of GaO X3 and the region mainly composed of In X2 Zn Y2 O Z2 or InO X1 and the region mainly composed of InO.

[0319] When one or more elements selected from aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc. are included in CAC-OS to replace gallium, CAC-OS refers to the following composition: nanoparticle-like regions mainly composed of this element and nanoparticle-like regions mainly composed of In are observed to be randomly dispersed in a mosaic pattern in some parts.

[0320] CAC-OS can be formed, for example, by a sputtering method under the condition of not intentionally heating the substrate. When forming CAC-OS by a sputtering method, as the film-forming gas, one or more gases selected from inert gases (typically argon), oxygen gas, and nitrogen gas can be used. In addition, the lower the flow ratio of oxygen gas in the total flow rate of the film-forming gas during film formation, the better. For example, the flow ratio of oxygen gas is set to be 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0321] CAC-OS has the following characteristics: When measured by θ / 2θ scanning using the out-of-plane method, which is one of the X-ray diffraction (XRD) measurement methods, no distinct peak is observed. That is, according to X-ray diffraction, it can be known that there is no orientation in the a-b plane direction and the c-axis direction in the measurement region.

[0322] In addition, in the electron diffraction pattern of CAC-OS obtained by irradiating an electron beam with a beam diameter of 1 nm (also called a nano-beam), a bright annular region and multiple bright spots within the annular region are observed. Thus, from the electron diffraction pattern, it can be known that the crystal structure of CAC-OS has an nc (nano-crystal) structure without orientation in the plane direction and the cross-sectional direction.

[0323] In addition, for example, in the CAC-OS of In-Ga-Zn oxide, from the EDX surface analysis image obtained by energy dispersive X-ray spectroscopy (EDX), it can be confirmed that there are regions mainly composed of GaO X3 and regions mainly composed of In X2 Zn Y2 O Z2 or InO X1 distributed unevenly and mixed.

[0324] The structure of CAC-OS is different from that of the IGZO compound in which metal elements are uniformly distributed, and it has properties different from those of the IGZO compound. In other words, CAC-OS has regions mainly composed of GaO X3 etc. and regions mainly composed of In X2 Zn Y2 O Z2 or InO X1 separated from each other and a mosaic-like structure with regions mainly composed of each element.

[0325] Here, the conductivity of the region mainly composed of In X2 Zn Y2 O Z2 or InO X1 is higher than that of the region mainly composed of GaO X3 etc. In other words, when carriers flow through the region mainly composed of In X2 Zn Y2 O Z2 or InO X1 it exhibits the conductivity of an oxide semiconductor. Therefore, when carriers flow through the region mainly composed of In X2 Zn Y2 OZ2 or InO X1 When a region mainly composed of Z2 or InO is distributed in a cloud shape in an oxide semiconductor, a high field-effect mobility (μ) can be achieved.

[0326] On the other hand, the insulating property of a region mainly composed of GaO X3 etc. is higher than that of a region mainly composed of In X2 Zn Y2 O Z2 or InO X1 That is, when a region mainly composed of GaO X3 etc. is distributed in an oxide semiconductor, leakage current can be suppressed and good switching operation can be achieved.

[0327] Therefore, when CAC-OS is used for a semiconductor element, high on-state current (I X3 ) and high field-effect mobility (μ) can be achieved through the complementary action of the insulating property caused by GaO X2 etc. and the conductivity caused by In Y2 O Z2 or InO X1 . on

[0328] In addition, a semiconductor element using CAC-OS has high reliability. Therefore, CAC-OS is suitable for various semiconductor devices such as displays.

[0329] This embodiment can be appropriately combined with other embodiments.

[0330] Embodiment 5

[0331] In this embodiment, an electronic device of one aspect of the present invention will be described.

[0332] Examples of the electronic device include: a television device; a desktop or notebook personal computer; a display for a computer, etc.; a digital camera; a digital video camera; a digital photo frame; a mobile phone; a portable game console; a portable information terminal; a sound reproduction device; a large game machine such as a pachinko machine, etc.

[0333] Figures 17A to 17C A portable information terminal is shown. The portable information terminal of this embodiment has, for example, one or more functions selected from a telephone, a notebook, an information reading device, etc. Specifically, the portable information terminal of this embodiment can be used as a smartphone or a smartwatch. The portable information terminal of this embodiment can execute various application programs such as a mobile phone, an email, reading and editing of articles, music playback, video playback, network communication, and computer games, for example. Figures 17A to 17CThe portable information terminal shown can have various functions. For example, it can have the following functions: displaying various information (such as still images, moving images, text images, etc.) on the display unit; a touch screen; displaying a calendar, date, or time, etc.; controlling processing by using various software (programs); performing wireless communication; connecting to various computer networks by using the wireless communication function; sending or receiving various data by using the wireless communication function; reading out programs or data stored in a recording medium and displaying them on the display unit, etc. Note that Figures 17A to 17C The functions of the portable information terminal shown are not limited to the above functions, but can also have other functions.

[0334] Figures 17A to 17C The portable information terminal shown can execute various application programs such as mobile phones, e-mails, reading and editing of articles, music playback, network communication, computer games, etc. In addition, Figures 17A to 17C The portable information terminal shown can perform short-range wireless communication based on a communication standard. For example, by communicating with a wireless communication-enabled headset, Figure 17C The watch-type portable information terminal 820 shown can perform hands-free calls.

[0335] Figure 17A The portable information terminal 800 shown includes a housing 811, a display unit 812, operation buttons 813, an external connection port 814, a speaker 815, a microphone 816, etc. The display unit 812 of the portable information terminal 800 has a flat surface.

[0336] Figure 17B The portable information terminal 810 shown includes a housing 811, a display unit 812, operation buttons 813, an external connection port 814, a speaker 815, a microphone 816, a camera 817, etc. The display unit 812 of the portable information terminal 810 has a curved surface.

[0337] Figure 17C A watch-type portable information terminal 820 is shown. The portable information terminal 820 includes a housing 811, a display unit 812, a speaker 815, operation keys 818 (including a power switch or an operation switch), etc. The outer shape of the display unit 812 of the portable information terminal 820 is circular. The display unit 812 of the portable information terminal 820 has a flat surface.

[0338] The display device of one aspect of the present invention can be used for the display unit 812. Thus, a portable information terminal including a display unit with a high aperture ratio can be manufactured.

[0339] In the portable information terminal according to this embodiment, the display unit 812 is provided with a touch sensor. By touching the display unit 812 with a finger or a stylus, various operations such as making a call or inputting text can be performed.

[0340] In addition, by operating the operation button 813, the power can be turned on and off, or the type of the image displayed on the display unit 812 can be switched. For example, the screen for writing an email can be switched to the main menu screen.

[0341] In addition, by providing a detection device such as a gyro sensor or an acceleration sensor inside the portable information terminal, the orientation (portrait or landscape) of the portable information terminal can be determined, and the screen display orientation of the display unit 812 can be automatically switched. In addition, the switching of the screen display orientation can also be performed by touching the display unit 812, operating the operation button 813, or inputting sound using the microphone 816.

[0342] In Figure 18A In the television device 7100 shown, a display unit 7102 is assembled in a housing 7101. An image can be displayed by the display unit 7102. The display device according to one aspect of the present invention can be used for the display unit 7102. Thus, a television device including a display unit with a high aperture ratio can be manufactured. A structure in which the housing 7101 is supported by a bracket 7103 is shown here.

[0343] The operation of the television device 7100 can be performed by using the operation switch provided in the housing 7101 or an additional remote control unit 7111. By using the operation keys provided in the remote control unit 7111, the channel and volume can be operated, and the image displayed on the display unit 7102 can be operated. In addition, a structure in which a display unit for displaying the information output from the remote control unit 7111 is provided in the remote control unit 7111 can also be adopted.

[0344] The television device 7100 is configured to include a receiver, a modem, etc. General television broadcasts can be received by the receiver. Furthermore, by connecting to a communication network in a wired or wireless manner through the modem, one-way (from the sender to the receiver) or two-way (between the sender and the receiver or between the receivers, etc.) information communication can be performed.

[0345] Figure 18B The computer 7200 shown includes a main body 7201, a housing 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. This computer is manufactured by using the display device according to one aspect of the present invention for its display unit 7203. Thus, a computer including a display unit with a high aperture ratio can be manufactured.

[0346] Figure 18CThe shown camera 7300 includes a housing 7301, a display unit 7302, operation buttons 7303, a shutter button 7304, etc. Additionally, the camera 7300 is equipped with a detachable lens 7306.

[0347] The display device of one embodiment of the present invention can be used for the display unit 7302. Thus, a camera including a display unit with a high aperture ratio can be manufactured.

[0348] Here, although the camera 7300 has a structure that allows the lens 7306 to be detached from the housing 7301 for replacement, the lens 7306 and the housing 7301 can also be formed integrally.

[0349] By pressing the shutter button 7304, the camera 7300 can capture still images or moving images. Additionally, the display unit 7302 can also have the function of a touch screen, and imaging can be performed by touching the display unit 7302.

[0350] Furthermore, the camera 7300 can also be equipped with an additional flash device and a viewfinder, etc. Additionally, these components can also be assembled in the housing 7301.

[0351] This embodiment can be appropriately combined with other embodiments.

[0352] Example 1

[0353] In this example, the cross-sectional structures of the display unit and the scan line driver circuit unit of the display device of one embodiment of the present invention are examined, and the evaluation results of the light transmittance of the contact portion between the transistor and the pixel electrode provided in the display area are described.

[0354] Figure 19 The cross-sectional structures of the display unit and the scan line driver circuit unit of the display device of this example are shown.

[0355] Figure 19 The shown display device is an example of a transmissive liquid crystal display device using a vertical electric field mode liquid crystal element.

[0356] As Figure 19 shown, the display device includes a substrate 51, transistors 201, 206, a liquid crystal element 40, a capacitor 219, alignment films 133a, 133b, a connection portion 204, an adhesive layer 141, a coloring layer 131, a light-shielding layer 132, a protective layer 121, a substrate 61, a polarizer 130, etc.

[0357] The display unit 62 includes transistors 206, a liquid crystal element 40, and a capacitor 219.

[0358] The transistor 206 includes a gate 221, an insulating layer 213, a conductive layer 222a, a conductive layer 222c, and a semiconductor layer 231.

[0359] Both the conductive layer 222a and the conductive layer 222c are connected to the semiconductor layer 231.

[0360] The liquid crystal element 40 is a liquid crystal element adopting the VA mode. The liquid crystal element 40 includes a pixel electrode 111, a common electrode 112, and a liquid crystal layer 113. The liquid crystal layer 113 is located between the pixel electrode 111 and the common electrode 112.

[0361] The pixel electrode 111 is electrically connected to the semiconductor layer 231 included in the transistor 206 through the conductive layer 222c.

[0362] The conductive layer 222c is used as one of a pair of electrodes included in the capacitor 219. The conductive layer 217a is used as the other of a pair of electrodes included in the capacitor 219. The conductive layer 222c and the conductive layer 217a overlap with each other with the insulating layer 213 therebetween. The conductive layer 217b is connected to the conductive layer 218.

[0363] Here, a conductive material that allows visible light to pass through is used for the semiconductor layer 231, the conductive layer 222c, the conductive layer 217a, the conductive layer 217b, and the conductive layer 218. The conductive layer 217a and the conductive layer 217b can be formed using the same process and the same material. The conductive layer 218 and the conductive layer 222c can be formed using the same process and the same material. Thus, the contact portion between the pixel electrode 111 and the transistor 206, the contact portion between the conductive layer 217b and the conductive layer 218, and the capacitor 219 can be provided in the display area 68. Therefore, the aperture ratio can be increased.

[0364] Next, Figure 19 an example of the material of each layer of the transistor 206 shown and an example of the forming method will be described.

[0365] First, as the conductive layer 217a and the conductive layer 217b, a conductive film that allows visible light to pass through (for example, ITSO) is formed. Then, as the gate 221, a metal film such as a Cu film is formed by sputtering. This metal film is also used as a scanning line. In addition, this metal film can be used and the gate wiring of the transistor in the peripheral circuit can be formed using the same process as that for the gate 221.

[0366] Next, as the gate insulating layer 213, a stacked layer of a silicon nitride film and a silicon oxynitride film is formed. Next, as the semiconductor layer 231, a stacked layer of a CAC-OS film and a CAAC-OS film is formed by sputtering. By forming a CAAC-OS film with high chemical solution resistance and plasma resistance on the CAC-OS film, the semiconductor layer 231 is not easily damaged in the transistor manufacturing process. Next, as the conductive layer 222c serving as a source electrode or a drain electrode, an indium zinc oxide film is formed by sputtering. Both the semiconductor layer 231 and the conductive layer 222c can be formed by wet etching. When forming the conductive layer 222c, in order to improve the selectivity to prevent the semiconductor layer 231 from being etched, the conductive layer 222c is preferably formed using an etching solution different from the etching solution used when forming the semiconductor layer 231. In addition, the indium zinc oxide film can also be used to form the conductive layer 218 in the same process as the conductive layer 222c.

[0367] Next, as the signal line and the conductive layer 222a, a metal film such as a Cu film is formed by sputtering. In addition, the source wiring and the drain wiring of the transistor in the peripheral circuit can also be formed using the metal film in the same process as the signal line and the conductive layer 222a.

[0368] Next, as the passivation films, the insulating layer 212 and the insulating layer 214, a stacked layer of a silicon oxynitride film and a silicon nitride film is formed using a PECVD apparatus. Then, an acrylic resin is applied as the insulating layer 215 having a planarization function to form an opening (contact hole). Then, an ITO film is formed as the pixel electrode 111.

[0369] In addition, as the gate electrode of the transistor included in the pixel, a Cu film formed as the scanning line is preferably used. Thereby, light from the backlight can be suppressed from irradiating the channel formation region. In Figure 7 , the contact portion between the transistor 206 and the pixel electrode 111 and the capacitor 219 can transmit visible light.

[0370] Next, a stacked structure that can be used in the region 139 in Figure 19 is manufactured, and Figure 20 the measurement results of its light transmittance are shown. In addition, Figure 20 the light transmittance of the glass (substrate 51) is also shown. The light transmittance is measured using a spectrophotometer U-4100 (manufactured by Hitachi High-Tech Science Corporation).

[0371] It can be seen from Figure 20 that in one aspect of the present invention, the stacked structure formed to improve the aperture ratio transmits visible light. From this, it can be known that by forming the contact portion between the transistor 206 and the pixel electrode 111, the capacitor 219, etc. using a material that transmits visible light, the power consumption of the backlight can be reduced.

[0372] Example 2

[0373] In this example, the cross-sectional structures of the display unit and the scan line driver circuit unit of one embodiment of the present invention are examined, and the evaluation results of the light transmittance of the transistors provided in the display area are described.

[0374] Refer to Figure 21A1 、 Figure 21B1 and Figure 21C1 and also Figure 22A1 、 Figure 22B1 、 Figure 22C1 and Figure 22D1 The manufacturing method of the transistors included in the display unit of the display device of this example is described. Refer to Figure 21A2 、 Figure 21B2 and Figure 21C2 and also Figure 22A2 、 Figure 22B2 、 Figure 22C2 and Figure 22D2 The manufacturing method of the transistors included in the scan line driver circuit unit of the display device of this example is described.

[0375] First, a conductive layer 217s is formed on the substrate 51, and a conductive layer 224s is formed on the conductive layer 217s ( Figure 21A1 、 Figure 21A2 ). The conductive layer 217s is formed using a conductive material that allows visible light to pass through (for example, ITSO). The conductive layer 224s is preferably formed using a conductive material such as metal whose resistance is lower than that of the conductive layer 217s. For example, as the conductive layer 224s, a metal film such as a Cu film is formed by a sputtering method.

[0376] Next, the conductive layer 217s and the conductive layer 224s are processed to form gates ( Figure 21B1 and Figure 21B2 ). In the display unit, an island-shaped conductive layer 217 ( Figure 21B1 ) is formed, and in the scan line driver circuit unit, a stacked structure of the island-shaped conductive layer 217 and the island-shaped conductive layer 224 is formed ( Figure 21B2 ). When forming the gates, it is preferable to use a multi-gray scale mask (halftone mask, gray scale mask, etc.). When using a multi-gray scale mask, gates that allow visible light to pass through can be formed in the display unit without increasing the number of masks, and gates and gate wirings with low resistance can be formed in the scan line driver circuit unit.

[0377] Next, an insulating layer 213 used as a gate insulating layer is formed, and a semiconductor layer 231 is formed on the insulating layer 213 ( Figure 21C1 、 Figure 21C2)。In this embodiment, as the insulating layer 213, a stacked layer of a silicon nitride film and a silicon oxynitride film is formed. In this embodiment, as the semiconductor layer 231, a stacked layer of a CAC-OS film and a CAAC-OS film is formed by a sputtering method. By forming a CAAC-OS film having high chemical solution resistance and plasma resistance on the CAC-OS film, the semiconductor layer 231 is not easily damaged in the transistor manufacturing process. By using an oxide semiconductor, a semiconductor layer 231 that transmits visible light can be formed.

[0378] Next, a conductive layer 222s is formed, and a conductive layer 222t is formed on the conductive layer 222s ( Figure 22A1 、 Figure 22A2 ). The conductive layer 222s is formed of a conductive material that transmits visible light. In this embodiment, an indium zinc oxide film is formed as the conductive layer 222s. The conductive layer 222t is preferably formed of a conductive material such as a metal having a lower resistance than the conductive layer 222s.

[0379] Next, the conductive layer 222s and the conductive layer 222t are processed to form a source electrode and a drain electrode ( Figure 22B1 、 Figure 22B2 ). In the display portion and the scan line driver circuit portion, an island-shaped conductive layer 222b and an island-shaped conductive layer 222c connected to a part of the semiconductor layer 231 are formed ( Figure 22B1 、 Figure 22B2 ). In the display portion, only an island-shaped conductive layer 222a connected to a part of the island-shaped conductive layer 222b remains as the remaining portion of the conductive layer 222t, and many parts of the transistor transmit visible light ( Figure 22B1 ). On the other hand, in the scan line driver circuit portion, an island-shaped conductive layer 222a and an island-shaped conductive layer 222d formed by processing the conductive layer 222t are provided on the island-shaped conductive layer 222b and the island-shaped conductive layer 222c ( Figure 22B2 ). When forming the source electrode and the drain electrode, similar to when forming the gate electrode, it is preferable to use a multi-gray scale mask. When using a multi-gray scale mask, a source electrode and a drain electrode that transmit visible light can be formed in the display portion without increasing the number of masks, and a source electrode, a drain electrode, a source wiring, and a drain wiring having low resistance can be formed in the driver circuit portion. The semiconductor layer 231, the source electrode, and the drain electrode can all be formed by wet etching. When forming the source electrode and the drain electrode, in order to improve the selectivity to prevent the semiconductor layer 231 from being etched, the source electrode and the drain electrode are preferably formed using an etching solution different from the etching solution used when forming the semiconductor layer 231.

[0380] Next, an insulating layer 212 used as a gate insulating layer is formed, and a gate 223 is formed on the insulating layer 212. The gate 223 is formed of a conductive material that transmits visible light. In this embodiment, as the insulating layer 212, a stacked layer of a silicon oxynitride film and a silicon nitride film is formed using a PECVD apparatus. AsFigure 22C1 , Figure 22C2 As shown, the gate 223 may also be provided only in the scan line driving circuit section. In addition, as Figure 22D1 , Figure 22D2 shown, the gate 223 may also be provided in the display section and the scan line driving circuit section.

[0381] Thus, the transistors included in the display device of this embodiment can be manufactured.

[0382] Next, a stacked structure that can be used for the region 140 in Figure 22C1 is manufactured, and Figure 23 the measurement results of its light transmittance are shown. In addition, Figure 23 the light transmittance of glass (substrate 51) is also shown. The light transmittance is measured using a spectrophotometer U-4100 (manufactured by Hitachi High-Tech Science Corporation).

[0383] As Figure 23 is known, in one aspect of the present invention, the stacked structure formed to increase the aperture ratio transmits visible light. From this, it can be seen that by forming many parts of the transistors in the display section using a material that transmits visible light, the power consumption of the backlight can be reduced.

[0384] Symbol Description

[0385] 34 Capacitor

[0386] 40 Liquid crystal element

[0387] 45 Light

[0388] 51 Substrate

[0389] 61 Substrate

[0390] 62 Display section

[0391] 63 Connection section

[0392] 64 Driving circuit section

[0393] 65 Wiring

[0394] 66 Non-display area

[0395] 68 Display area

[0396] 72 FPC

[0397] 72a FPC

[0398] 72b FPC

[0399] 73 IC

[0400] 73a IC

[0401] 73b IC

[0402] 81 Scanning line

[0403] 82 Signal line

[0404] 100A Display device

[0405] 100B Display device

[0406] 100C Display device

[0407] 100D Display device

[0408] 111 Pixel electrode

[0409] 112 Common electrode

[0410] 113 Liquid crystal layer

[0411] 121 Protective layer

[0412] 127 Electrode

[0413] 128 Electrode

[0414] 130 Polarizer

[0415] 131 Coloring layer

[0416] 132 Light-shielding layer

[0417] 133a Alignment film

[0418] 133b Alignment film

[0419] 137 Wiring

[0420] 138 Wiring

[0421] 139 Area

[0422] 140 Area

[0423] 141 Adhesive layer

[0424] 162 Substrate

[0425] 201 Transistor

[0426] 204 Connection part

[0427] 206 Transistor

[0428] 212 Insulating layer

[0429] 213 Insulating layer

[0430] 214 Insulating layer

[0431] 215 Insulating layer

[0432] 217 Conductive layer

[0433] 217a Conductive layer

[0434] 217b Conductive layer

[0435] 217s Conductive layer

[0436] 218 Conductive layer

[0437] 219 Capacitor

[0438] 220 Insulating layer

[0439] 221 Gate

[0440] 222a Conductive layer

[0441] 222b Conductive layer

[0442] 222c Conductive layer

[0443] 222d Conductive layer

[0444] 222s Conductive layer

[0445] 222t Conductive layer

[0446] 223 Gate

[0447] 224 Conductive layer

[0448] 224s Conductive layer

[0449] 228 Scanning line

[0450] 229 Signal line

[0451] 231 Semiconductor layer

[0452] 231a First metal oxide layer

[0453] 231b Second metal oxide layer

[0454] 242 Connector

[0455] 244 Capacitance line

[0456] 251 Conductive layer

[0457] 350A Touch screen

[0458] 350B Touch screen

[0459] 370 Display device

[0460] 375 Input device

[0461] 376 Input device

[0462] 379 Display device

[0463] 501 Display element

[0464] 506 Pixel circuit

[0465] 521 Electrode

[0466] 522 Electrode

[0467] 551 Pulse voltage output circuit

[0468] 552 Current detection circuit

[0469] 553 Capacitor

[0470] 800 Portable information terminal

[0471] 810 Portable information terminal

[0472] 811 Housing

[0473] 812 Display unit

[0474] 813 Operation button

[0475] 814 External connection port

[0476] 815 Speaker

[0477] 816 Microphone

[0478] 817 Camera

[0479] 818 Operation key

[0480] 820 Portable information terminal

[0481] 7100 Television device

[0482] 7101 Housing

[0483] 7102 Display unit

[0484] 7103 Bracket

[0485] 7111 Remote operation unit

[0486] 7200 Computer

[0487] 7201 Main body

[0488] 7202 Housing

[0489] 7203 Display unit

[0490] 7204 Keyboard

[0491] 7205 External connection port

[0492] 7206 Pointing device

[0493] 7300 Camera

[0494] 7301 Housing

[0495] 7302 Display unit

[0496] 7303 Operation button

[0497] 7304 Shutter button

[0498] 7306 Lens

Claims

1. A display device, include: Liquid crystal element; transistor; Scan line; as well as Signal line, Wherein, the liquid crystal element comprises a pixel electrode, a liquid crystal layer and a common electrode. The scanning line and the signal line are both electrically connected to the transistor, The scanning line and the signal line both include a metal layer, The transistor comprises: A semiconductor layer including a stack of a first metal oxide layer and a second metal oxide layer; A first conductive layer connected to the semiconductor layer; and a second conductive layer connected to the semiconductor layer; and The pixel electrode is electrically connected to the semiconductor layer through the second conductive layer. The first metal oxide layer includes a region having lower crystallinity than the second metal oxide layer, The pixel electrode, the common electrode, and the second conductive layer all transmit visible light, and the visible light passes through the second conductive layer and the liquid crystal element and is emitted from the display device. The pixel electrode and the common electrode both contain at least one of indium, zinc and tin, the first conductive layer contains a metal film, and The second conductive layer includes an oxide conductive layer.

2. The display device according to claim 1, wherein the second conductive layer comprises indium, metal M and zinc, and wherein M represents aluminum, gallium, yttrium or tin. The display device according to claim 1 , wherein the second conductive layer comprises indium, zinc, and oxygen.

4. The display device according to claim 1, The scan line includes a portion overlapping the semiconductor layer.

5. A display device, include: Liquid crystal element; transistor; Scan line; as well as Signal line, Wherein, the liquid crystal element comprises a pixel electrode, a liquid crystal layer and a common electrode. The scanning line and the signal line are both electrically connected to the transistor, The scanning line and the signal line both include a metal layer, The transistor comprises: Gate; a semiconductor layer overlapping the gate via a gate insulating layer, the semiconductor layer comprising a stack of a first metal oxide layer and a second metal oxide layer; and a source electrode and a drain electrode, each connected to the semiconductor layer; and The pixel electrode is electrically connected to the semiconductor layer through one of the source electrode and the drain electrode. The first metal oxide layer includes a region having lower crystallinity than the second metal oxide layer, The pixel electrode, the common electrode, and one of the source electrode and the drain electrode all contain a material that transmits visible light. The visible light is emitted from the display device through the one of the source electrode and the drain electrode and the liquid crystal element, The other of the source electrode and the drain electrode includes a material having a function of shielding visible light, and The pixel electrode and the common electrode both contain at least one of indium, zinc and tin. The display device according to claim 5 , wherein the other of the source electrode and the drain electrode comprises a metal.

7. The display device according to claim 5, wherein the one of the source electrode and the drain electrode comprises indium, metal M and zinc, and wherein M represents aluminum, gallium, yttrium or tin.

8. A display device, include: Liquid crystal element; transistor; Scan line; as well as Signal line, Wherein, the liquid crystal element comprises a pixel electrode, a liquid crystal layer and a common electrode. The scanning line and the signal line are both electrically connected to the transistor, The scanning line and the signal line both include a metal layer, The transistor comprises: Gate; a gate insulating layer on the gate; a semiconductor layer overlapping the gate via the gate insulating layer, the semiconductor layer comprising a stack of a first metal oxide layer and a second metal oxide layer; A first conductive layer connected to the semiconductor layer; and a second conductive layer connected to the semiconductor layer; and The pixel electrode is electrically connected to the semiconductor layer through the second conductive layer. The first metal oxide layer includes a region having lower crystallinity than the second metal oxide layer, The pixel electrode, the common electrode and the second conductive layer all contain a material that allows visible light to pass through. The visible light passes through the second conductive layer and the liquid crystal element and is emitted from the display device. The pixel electrode and the common electrode both contain at least one of indium, zinc and tin, and The first conductive layer includes a material having a function of shielding visible light. The display device according to claim 8 , wherein the first conductive layer comprises metal.

10. The display device according to claim 8 or 9, wherein the second conductive layer comprises indium, metal M and zinc, and wherein M represents aluminum, gallium, yttrium or tin.

11. The display device according to claim 8 or 9, wherein the second conductive layer contains indium, zinc and oxygen. 12 . The display device according to claim 1 , wherein the second metal oxide layer is located on the first metal oxide layer.

13. The display device according to any one of claims 1, 5 and 8, wherein the first metal oxide layer and the second metal oxide layer each contain indium, metal M and zinc, and wherein M represents aluminum, gallium, yttrium or tin.

14. The display device according to claim 13, wherein in at least one of the first metal oxide layer and the second metal oxide layer, the atomic number ratio of the indium, the metal M and the zinc is 4:x:y, wherein x is greater than or equal to 1.5 and less than or equal to 2.5, and y is greater than or equal to 2 and less than or equal to 4.

15. The display device according to claim 13, wherein in at least one of the first metal oxide layer and the second metal oxide layer, the atomic number ratio of the indium, the metal M and the zinc is 5:x:y, wherein x is greater than 0.5 and less than 1.5, and y is greater than 5 and less than 7. 16 . The display device according to claim 1 , wherein the first metal oxide layer and the second metal oxide layer each contain indium, gallium, and zinc.

17. The display device according to any one of claims 1, 5 and 8, wherein the second metal oxide layer comprises a crystalline portion, and The crystal part has c-axis orientation.

Images