Display device

Abstract

This invention provides a display device capable of reducing power consumption. The invention increases the aperture ratio of the display device. The display device includes pixels having a first sub-pixel and a second sub-pixel. The first sub-pixel includes a first color layer and a first transistor, and the second sub-pixel includes a second color layer and a second transistor. The portions of the semiconductor layers comprising the first and second transistors that form channels are arranged at least overlapping the first color layer. The first color layer absorbs light with a wavelength shorter than that absorbed by the second color layer, while the semiconductor layers, electrodes, and wiring constituting the transistor transmit visible light.

Description

Technical Field

[0001] One embodiment of the present invention relates to a display device.

[0002] One embodiment of the present invention is not limited to the above-described technical fields. As an example of the technical field of one embodiment of the present invention disclosed in this specification, etc., semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting equipment, input devices, input / output devices, driving methods thereof, or manufacturing methods thereof may be cited.

[0003] Note that in this specification, etc., a semiconductor device refers to any device capable of operating by utilizing the characteristics of semiconductors. Transistors, semiconductor circuits, arithmetic processing devices, and memory devices are all embodiments of semiconductor devices. In addition, imaging devices, electro-optical devices, power generation devices (including thin-film solar cells, organic thin-film solar cells, etc.), and electronic devices sometimes include semiconductor devices. Prior Technology

[0004] There is a demand for low-power electronic devices. In particular, since portable electronic devices such as smartphones or tablets rely on batteries for power, high power consumption will shorten the lifespan of a single charge.

[0005] Liquid crystal displays (LCDs) are known as one type of display device installed in electronic devices. Transmissive liquid crystal displays represent contrast by controlling the amount of light transmitted from the backlight using the optical modulation of liquid crystals, thereby displaying images.

[0006] For example, there are known active matrix liquid crystal display devices that use transistors with metal oxide as channel regions as switching elements connected to the electrodes of each pixel (Patent Document 1 and Patent Document 2).

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2007-123861 [Patent Document 2] Japanese Patent Application Publication No. 2007-96055 Summary of the Invention

[0008] One method to reduce the power consumption of a liquid crystal display device (LCD panel) is to efficiently extract light from the backlight.

[0009] One objective of one embodiment of the present invention is to provide a display device capable of reducing power consumption. Another objective of one embodiment of the present invention is to increase the aperture ratio of the display device. Another objective of one embodiment of the present invention is to provide a display device with both high aperture ratio and high reliability. Finally, another objective of one embodiment of the present invention is to provide a novel display device.

[0010] 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. Furthermore, objectives other than those described above can be derived from the description in the specification, drawings, claims, etc.

[0011] One embodiment of the present invention is a display device, including a first color layer; a second color layer; a first transistor; a second transistor; a first display element; and a second display element. The first display element is electrically connected to the first transistor and overlaps with the first color layer. The second display element is electrically connected to the second transistor and overlaps with the second color layer. The first transistor includes a first semiconductor layer. The second transistor includes a second semiconductor layer. Both the first semiconductor layer and the second semiconductor layer include portions overlapping the first color layer.

[0012] Another embodiment of the present invention is a display device, comprising: a first color layer; a second color layer; a third color layer; a first transistor; a second transistor; a third transistor; a first display element; a second display element; and a third display element. The first display element is electrically connected to the first transistor and overlaps with the first color layer. The second display element is electrically connected to the second transistor and overlaps with the second color layer. The third display element is electrically connected to the third transistor and overlaps with the third color layer. The first transistor includes a first semiconductor layer. The second transistor includes a second semiconductor layer. The third transistor includes a third semiconductor layer. The first semiconductor layer, the second semiconductor layer, and the third semiconductor layer all include portions overlapping the first color layer.

[0013] In the above structure, preferably, the first color layer transmits light with a wavelength longer than that transmitted by the second color layer. Alternatively, the first color layer preferably transmits red light.

[0014] In the above structure, it is preferable to include a light source that emits white light. In this case, the first color layer is preferably located between the light source and the first semiconductor layer, and between the light source and the second semiconductor layer.

[0015] In the above structure, the first transistor preferably includes a first gate electrode and a first electrode and a second electrode connected to the first semiconductor layer. The second transistor preferably includes a second gate electrode and a third electrode and a fourth electrode connected to the second semiconductor layer. In this case, the first electrode, the second electrode, the third electrode, and the fourth electrode all include portions that transmit visible light and overlap with the first color layer. Preferably, both the first gate electrode and the second gate electrode include portions that transmit visible light and overlap with the first color layer. Alternatively, both the first gate electrode and the second gate electrode preferably block visible light.

[0016] In the above structure, it is preferable to include a first wiring and a second wiring. Preferably, the first electrode is electrically connected to the first wiring, the second electrode is electrically connected to the first display element, the third electrode is electrically connected to the second wiring, and the fourth electrode is electrically connected to the second display element. The fourth electrode preferably intersects with the second wiring. Alternatively, the fourth electrode preferably intersects with both the first and second wirings. Alternatively, the fourth electrode preferably does not intersect with either the first or second wiring.

[0017] In the above structure, it is preferable to include a first wiring and a second wiring. In this case, the first transistor includes a first gate electrode, and the second transistor includes a second gate electrode. In this case, the first semiconductor layer includes a portion overlapping with the first gate electrode and a portion connected to the first wiring. The second semiconductor layer includes a portion overlapping with the second gate electrode and a portion connected to the second wiring. Preferably, the second semiconductor layer intersects with the second wiring. Alternatively, the second semiconductor layer preferably intersects with both the second wiring and the first wiring. Alternatively, the second semiconductor layer preferably does not intersect with either the first wiring or the second wiring.

[0018] In the above structure, both the first semiconductor layer and the second semiconductor layer preferably contain metal oxides.

[0019] In the above structure, the first display element preferably includes a fifth electrode, a sixth electrode, and a liquid crystal. Preferably, the fifth electrode is electrically connected to the first transistor, and both the fifth and sixth electrodes are transparent to visible light.

[0020] According to one embodiment of the present invention, a display device capable of reducing power consumption can be provided. According to one embodiment of the present invention, the aperture ratio of the display device can be increased. According to one embodiment of the present invention, a display device having a high aperture ratio and high reliability can be provided. According to one embodiment of the present invention, a novel display device can be provided.

[0021] Note that the description of these effects does not preclude the existence of other effects. Furthermore, one embodiment of the present invention does not necessarily require all of the aforementioned effects. Additionally, effects other than those described above can be derived from the description in the specification, drawings, claims, etc. Simple Explanation of the Diagram

[0022] In the diagram: Figures 1A to 1C are examples of the structure of the display device; Figure 2 is a structural example of a display device; Figures 3A and 3B are examples of the structure of a display device; Figure 4 is a structural example of a display device; Figure 5 shows a structural example of a display device; Figure 6 is a structural example of a display device; Figure 7 is a structural example of a display device; Figure 8 is a structural example of a display device; Figure 9 is a structural example of a display device; Figures 10A and 10B are structural examples of the display device; Figure 11 is a structural example of a display device; Figure 12 is a structural example of a display device; Figures 13A and 13B are structural examples of the display device; Figures 14A and 14B are structural examples of the display device; Figures 15A and 15B are structural examples of the display device; Figures 16A and 16B are structural examples of the display device; Figures 17A to 17D are structural examples of the input device; Figures 18A to 18D are structural examples of the input device; Figures 19A and 19B are examples of the structure of a touch panel; Figures 20A to 20C are circuit diagrams and timing diagrams; Figures 21A and 21B are examples of the structure of the display module; Figures 22A to 22D are examples of the structure of electronic devices; Figures 23A to 23C are examples of the structure of electronic devices. Implementation

[0023] The embodiments will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and those skilled in the art will readily understand that its methods and details can be varied in many ways without departing from the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited solely to the description of the embodiments shown below.

[0024] In the inventive structures described below, the same element symbols are used in different figures to represent the same parts or parts with the same function, and repeated descriptions are omitted. In addition, when parts with the same function are represented, the same shading lines are sometimes used, without additional element symbols.

[0025] In the various drawings described in this specification, the size of the structures, the thickness of the layers, and the area are sometimes exaggerated for clarity. Therefore, the invention is not necessarily limited to the dimensions shown in the drawings.

[0026] The ordinal numbers such as "first" and "second" used in this specification are appended to avoid confusion of components, and are not intended to limit the number of components.

[0027] A transistor is a type of semiconductor device that can amplify current or voltage, control the switching between conduction and non-conduction, etc. The transistors in this specification include IGFET (Insulated Gate Field Effect Transistor) and thin film transistor (TFT).

[0028] In this specification and the like, the display panel of one embodiment of the display device refers to a panel capable of displaying (outputting) images, etc., on a display surface. Therefore, the display panel is one embodiment of the output device.

[0029] In this specification, etc., a structure in which connectors such as FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) are mounted on the substrate of a display panel, or a structure in which ICs are directly mounted on the substrate in the form of COG (Chip On Glass) is referred to as a display panel module or display module, or simply as a display panel, etc.

[0030] Furthermore, in this specification, a touch sensor refers to a sensor capable of detecting the contact, pressure, or proximity of a detected object such as a finger or stylus. It may also have the function of detecting its position information. Therefore, a touch sensor is one embodiment of an input device. For example, a touch sensor may have a structure having more than one sensor element.

[0031] Furthermore, in this specification, the substrate including the touch sensor is sometimes referred to as a touch sensor panel, or simply as a touch sensor. Additionally, in this specification, a structure on which connectors such as FPCs or TCPs are mounted on the substrate of the touch sensor panel, or a structure on which an IC is mounted on the substrate in a COG manner, is sometimes referred to as a touch sensor panel module, touch sensor module, sensor module, or simply as a touch sensor.

[0032] Note that, in this specification and the like, the touch panel of one embodiment of the display device has the following functions: displaying (outputting) images on the display surface; and functioning as a touch sensor to detect when a detected object such as a finger or stylus touches, is pressed, or approaches the display surface. Therefore, the touch panel is one embodiment of an input / output device.

[0033] A touch panel can also be referred to as a display panel (or display device) with a touch sensor, or a display panel (or display device) with touch sensor functionality.

[0034] The touch panel may also include a display panel and a touch sensor panel. Alternatively, it may have a structure that incorporates touch sensors inside or on the surface of the display panel.

[0035] In addition, in this specification, structures with connectors such as FPC or TCP mounted on the substrate of a touch panel, or structures with ICs mounted on the substrate in a COG manner, are sometimes referred to as touch panel modules, display modules, or simply touch panels.

[0036] Implementation Method 1 In this embodiment, a display device according to one embodiment of the present invention will be described.

[0037] One embodiment of the present invention is a display device comprising a plurality of transmissive liquid crystal elements and transistors electrically connected to the liquid crystal elements.

[0038] A liquid crystal element includes a pair of electrodes and liquid crystal. Both electrodes are visible light luminescent. One of the electrodes is used as a pixel electrode and is electrically connected to a transistor. The other electrode is used as a common electrode and is supplied with the same potential as the other pixels.

[0039] The display area of ​​the display device has a matrix structure of multiple pixels. Each pixel includes two or more sub-pixels. Each sub-pixel includes a pixel electrode, a transistor used as a selection transistor, and a color layer.

[0040] For example, a pixel includes a first sub-pixel and a second sub-pixel. The first sub-pixel includes a first color layer and a first transistor, and the second sub-pixel includes a second color layer and a second transistor. In this case, the first transistor and the second transistor are arranged to overlap with the first color layer. More specifically, the portion of the semiconductor layer of the first transistor and the second transistor in which a channel is formed is arranged to overlap with the first color layer at least once.

[0041] Therefore, the light illuminating both the first and second transistors is transmitted through the first color layer. This ensures that the first transistor is affected by light exposure to the same degree as the second transistor. Consequently, contrast discrepancies between adjacent sub-pixels can be prevented.

[0042] Furthermore, it is preferable that the first color layer readily absorbs light whose wavelength is shorter than that absorbed by the second color layer. Particularly preferable is that the first color layer transmits light whose wavelength is longer than that transmitted by the second color layer and absorbs other visible light. Therefore, since the light obtained by removing short-wavelength light from the incident light through the first color layer illuminates the first and second transistors, the influence of light on these transistors can be reduced. Alternatively, the light transmitted through the first color layer can be made to have no effect on the individual transistors. Thus, a display device with extremely high reliability can be realized.

[0043] Here, when setting the backlight, it is preferable to arrange the backlight by distributing a first color layer between the first transistor and the second transistor and the backlight. This can suppress the influence of light emanating from the backlight onto the first transistor and the second transistor.

[0044] Alternatively, the first color layer can be sandwiched between the transistors on the side opposite to the backlight (the display side). In this case, the influence of external light incident on the display device from the display side on the transistors can be suppressed.

[0045] The semiconductor layer forming the channel for the first and second transistors is preferably a metal oxide (also known as an oxide semiconductor (OS)) exhibiting semiconductor properties. Furthermore, the semiconductor layer preferably includes a pair of low-resistance regions sandwiching the channel forming region. These low-resistance regions are those with higher conductivity than the channel forming region, and can also be described as oxide conductors (OC). Therefore, since the region where the semiconductor layer is disposed is used as a region that transmits visible light (also known as a transmission region), the aperture ratio of the display device can be increased.

[0046] The electrodes and wiring constituting the first and second transistors are preferably made of materials that transmit visible light. Metal oxides are particularly preferred. For example, the gate, source, and drain electrodes of the first and second transistors can be made of conductive materials that are transparent to light. This further improves the aperture ratio of the display device.

[0047] Since the low-resistance region, source electrode, and drain electrode of the semiconductor layer are transparent, their contacts can be used in the transmission region, thereby further improving the aperture ratio.

[0048] As described above, since the channel forming region of the semiconductor layer is configured to overlap with the first color layer, even if the gate electrode is transparent and light is irradiated through the first color layer into the channel forming region, the influence on each transistor can be suppressed.

[0049] For example, the first sub-pixel may have a structure in which the pixel electrode overlaps with a transparent semiconductor layer, gate electrode, source electrode, drain electrode, etc.

[0050] Each sub-pixel may also include a capacitor used as a storage capacitor. In this case, it is preferable to use a light-transmitting conductive material for the pair of electrodes constituting the capacitor and the wiring electrically connected to the capacitor. Since each capacitor is not easily affected by light, it can be arranged to overlap with the color layer of each sub-pixel.

[0051] Here, the source and drain electrodes can be made of transparent materials, and the gate electrode can be made of a light-shielding material. Preferably, the light-shielding gate electrode is positioned on one side of the display surface, and the first color layer is positioned closer to the backlight side than the transistors. Thus, the first color layer can suppress the influence of light from the backlight, and the light-shielding gate electrode can suppress the influence of external light incident from the display surface.

[0052] The wiring used to supply signals or potentials to each sub-pixel (also known as bus lines) can also be made of light-transmitting materials. Using light-shielding materials such as metals can reduce wiring resistance, making it preferable. Examples of bus lines include wiring supplied with gate signals (also known as gate lines), wiring supplied with source signals (also known as source lines or signal lines), and wiring supplied with common potentials or power potentials (also known as power lines). In this case, all parts except the bus line can be made transparent, thereby achieving a very high aperture ratio.

[0053] A pixel can also have three or more sub-pixels with different colors. In this case, the transistor can be placed in the region overlapping with the color layer that transmits the shortest wavelength of light, instead of the transistor itself, but rather in a manner that overlaps with other color layers. It is particularly preferred that the transistor of the sub-pixel be placed in a manner that overlaps with the color layer that transmits the longest wavelength of light.

[0054] For example, when a pixel includes sub-pixels corresponding to the three colors of red, green, and blue, the transistors included in each sub-pixel can be configured to overlap with a color layer other than blue, i.e., a red or green color layer. It is particularly preferred that the three transistors are configured to overlap with a red color layer.

[0055] The following diagram illustrates a more specific example.

[0056] [Structure Example 1] Figure 1A shows a perspective view of the display device 10. The display device 10 has a structure that attaches a substrate 11 and a substrate 12. In Figure 1A, the substrate 12 is shown in dashed lines. Furthermore, Figure 1A corresponds to a perspective view viewed from the side opposite to the display surface. In other words, in the display device 10, the side of the substrate 11 is the display surface side.

[0057] The display device 10 includes a display section 13, circuitry 14, and wiring 15. For example, a conductive layer 21, circuitry 14, and wiring 15, which are included in the display section 13 and serve as pixel electrodes, are provided on the substrate 11. Furthermore, FIG. 1A shows an example where an IC 17 and an FPC 16 are mounted on the substrate 11. Therefore, the structure shown in FIG. 1A can also be referred to as a display module.

[0058] Circuit 14 can, for example, use a circuit that is used as a scan line drive circuit.

[0059] Wiring 15 has the function of supplying signals or power to the display unit 13 and circuit 14. The signals or power are supplied to wiring 15 from the outside via FPC 16 or from IC 17.

[0060] Figure 1A shows an example of IC 17 being disposed on substrate 11 using COG (Chip On Glass) or similar methods. For example, IC 17 is used as an IC for signal line driving circuits, etc. Alternatively, IC 17 may not be disposed. Furthermore, IC 17 may also be mounted on FPC 16 using COF (Chip On Film) or similar methods.

[0061] Figure 1A shows an enlarged view of a portion of the display unit 13. Multiple conductive layers 21, including those for display elements, are arranged in a matrix within the display unit 13. The conductive layers 21 are used, for example, as pixel electrodes.

[0062] [Example of cross-sectional structure] Figure 1B shows an example of a cross-section along the cut line A1-A2 in Figure 1A. Figure 1B shows a cross-section including a region containing three adjacent pixels (subpixels). Here, an example is shown where a transmissive liquid crystal element 20 is used as a display element. In Figure 1B, the substrate 11 side is the display surface side.

[0063] The display device 10 has a structure in which liquid crystal 22 is sandwiched between substrate 11 and substrate 12. The liquid crystal element 20 includes a conductive layer 21 disposed on one side of substrate 11, a conductive layer 23 disposed on one side of substrate 12, and liquid crystal 22 therebetween. Furthermore, an alignment film 24a is disposed between liquid crystal 22 and conductive layer 21, and an alignment film 24b is disposed between liquid crystal 22 and conductive layer 23.

[0064] The conductive layer 21 is used as a pixel electrode. Furthermore, the conductive layer 23 is used as a common electrode, etc. Both the conductive layer 21 and the conductive layer 23 are capable of transmitting visible light. Therefore, the liquid crystal element 20 is a transmissive liquid crystal element.

[0065] Figure 1B shows three liquid crystal elements 20. The liquid crystal elements 20 overlap with color layers 41R, 41G, or 41B. Furthermore, a light-shielding layer 42 is provided between two color layers. An insulating layer 26 is provided to cover each color layer and the light-shielding layer 42, and a conductive layer 23 is provided to cover the insulating layer 26. Preferably, the light-shielding layer 42 is arranged to overlap with the contact portion of the transistor 30R and the conductive layer 21.

[0066] For example, color layer 41R transmits red light and absorbs other wavelengths of visible light. Color layer 41G transmits green light and absorbs other wavelengths of visible light. Color layer 41B transmits blue light and absorbs other wavelengths of light. Light 25R, light 25G, and light 25B transmitted through color layers 41R, 41G, or 41B can each have two or more peaks in the visible light region, preferably one peak in the visible light region. Here, color layer 41R transmits the longest wavelength of light among the three color layers and absorbs other wavelengths of light.

[0067] The colors of the light transmitted through color layers 41R, 41G, and 41B are not limited to these.

[0068] In Figure 1B, the area with color layer 41R is the display area 13R, the area with color layer 41G is the display area 13G, and the area with color layer 41B is the display area 13B. Furthermore, it is preferable to include a light-shielding area with a light-shielding layer 42 between the display areas of different colors.

[0069] A polarizing plate 39a is disposed on the outer side of substrate 11, and a polarizing plate 39b is disposed on the outer side of substrate 12. Furthermore, a backlight unit 90 is disposed on the outer side of polarizing plate 39b. In the display device 10 shown in FIG. 1B, one side of substrate 11 is the display surface side.

[0070] Transistors 30R, 30G, and 30B are disposed on substrate 11. Each transistor is used, for example, as a selection transistor for a sub-pixel. Transistor 30R is electrically connected to conductive layer 21 overlapping color layer 41R. Transistor 30G is electrically connected to conductive layer 21 overlapping color layer 41G. Transistor 30B is electrically connected to conductive layer 21 overlapping color layer 41B.

[0071] Figure 1C shows an enlarged view of a transistor 30 applicable to transistors 30R, 30G, and 30B. The transistor 30 shown in Figure 1C is a transistor with a so-called bottom-gate channel etch structure. The transistor 30 includes a conductive layer 31 serving as a gate electrode, an insulating layer 34 serving as a gate insulating layer, a semiconductor layer 32, and a pair of conductive layers 33 serving as source and drain electrodes. The portion of the semiconductor layer 32 overlapping the conductive layer 31 is used as a channel formation region. The semiconductor layer 32 and the conductive layer 33 are disposed in contact.

[0072] A conductive layer 21, used as a pixel electrode, is disposed on an insulating layer 81 and is electrically connected to a conductive layer 33 through an opening in the insulating layer 81. The insulating layer 81 is preferably used as a planarization layer.

[0073] Here, the conductive layer 31, semiconductor layer 32, conductive layer 33, and insulating layer 34 are all transparent to visible light. Therefore, as shown in Figures 1B and 1C, light 25R can pass through the transistor 30. By overlapping the transistor 30, liquid crystal element 20, and color layer 41R, the area where the transistor 30 is disposed is used as the transmission area 40t and is also used as part of the display area. Thus, a display device with a high aperture ratio (in other words, the ratio of the area of ​​the transmission area to the area of ​​the display area per unit area) can be realized.

[0074] As shown in Figure 1B, multiple transistors constituting a pixel are arranged overlapping a color layer 41R, and each transistor is illuminated with light 25R of the same wavelength and intensity. Therefore, when the electrical characteristics of each transistor are affected by the illumination of light 25R, the effect on each transistor can be made equal. This prevents differences in contrast between sub-pixels.

[0075] The light 25R that passes through the color layer 41R has the longest wavelength (in other words, lower energy) compared to other light. Since it does not include light with a shorter wavelength compared to red, it can also be said to be the light that is least easily absorbed by semiconductor layers 32, etc. Therefore, even with a structure in which light 25R passes through the semiconductor layers 32 of each transistor, a display device with high reliability can be realized.

[0076] As shown in Figure 2, similar to the transistor 30a, a conductive layer 31a that blocks visible light can also be used for the conductive layer used as the gate electrode. In this way, by shielding the display surface side of the semiconductor layer 32, external light incident from the display surface side can be prevented from reaching the semiconductor layer 32, thereby achieving a display device with higher reliability. On the other hand, since the portion where the conductive layer 31a is provided is used as the light-shielding region 40s, the aperture ratio of the structure shown in Figure 1C can be increased compared to the structure in Figure 2.

[0077] The above is an explanation of structure example 1.

[0078] [Structure Example 2] The following provides a more specific example of a display device.

[0079] [Pixel Structure Example 2-1] Figure 3A shows a top view of a pixel 40 viewed from the side opposite to the display surface (in other words, the side opposite to the backlight unit 90). Pixel 40 includes sub-pixels 40G, 40R, and 40B. Pixel 40 is connected to wiring 51, which is used as a gate line; wiring 52G, 52R, and 52B, which are used as source lines; and wiring 53, which is used as a power line.

[0080] Sub-pixels 40G, 40R, and 40B are respectively provided with color layers 41G, 41R, and 41B. Here, each color layer is indicated by dashed lines. In addition, components that represent only a portion (such as conductive layer 21) are omitted in Figure 3A.

[0081] In sub-pixel 40R, transistors 30G, 30R, 30B, and capacitor 60R are disposed in the area overlapping with color layer 41R. The conductive or semiconductor layer constituting each transistor and capacitor 60R is preferably made of a material that transmits visible light.

[0082] Figure 3A shows an example of a transistor with a bottom gate structure, which is included as a pixel 40, including transistors 30G, 30R, and 30B.

[0083] Sub-pixels 40G and 40B are respectively provided with capacitors 60G and 60B. Each capacitor is located in a region overlapping with color layer 41G or color layer 41B. Like capacitor 60R in sub-pixel 40R, each capacitor is preferably transparent to visible light. Furthermore, at least one of capacitors 60G and 60B may also be located in a region overlapping with color layer 41R of sub-pixel 40R. Capacitor 60R may also be located in a region overlapping with at least one of color layers 41G and 41B.

[0084] In pixel 40, wiring 51, wiring 52R, wiring 52G, wiring 52B, and wiring 53 can use materials that block visible light, while other layers use materials that transmit visible light. Figure 4 shows an example where pixel 40 is divided into a light-blocking region 40s that blocks visible light and a light-transmitting region 40t that transmits visible light. Thus, since almost all areas except the area where the busbar is located can be made into a light-transmitting region 40t, the aperture ratio can be improved compared to conventional display devices.

[0085] Figure 3B is a circuit diagram of pixel 40 shown in Figure 3A. In addition to the above-described structure, Figure 3B also shows liquid crystal element 20R, liquid crystal element 20G, and liquid crystal element 20B.

[0086] In transistor 30R, the gate is electrically connected to wiring 51, one of the source and drain is electrically connected to wiring 52R, and the other of the source and drain is electrically connected to one electrode of capacitor 60R and one electrode (pixel electrode) of liquid crystal element 20R.

[0087] In transistor 30G, the gate is electrically connected to wiring 51, one of the source and drain terminals crosses wiring 52R and is electrically connected to wiring 52G, and the other of the source and drain terminals crosses wiring 52R and wiring 52G and is electrically connected to one electrode of capacitor 60G and pixel electrode of liquid crystal element 20G.

[0088] In transistor 30B, the gate is electrically connected to wiring 51, one of the source and drain is electrically connected to wiring 52B, and the other of the source and drain is electrically connected to one electrode of capacitor 60B and the pixel electrode of liquid crystal element 20B.

[0089] The other electrode of capacitors 60R, 60G, and 60B is electrically connected to wiring 53.

[0090] [Example 2-1 of cross-sectional structure] Figure 5 shows cross-sections along cut lines B1-B2 and C1-C2 as shown in Figure 3A. Cut lines B1-B2 are lines passing through wiring 52R, transistor 30R, capacitor 60R, and wiring 53, etc., while cut lines C1-C2 are lines passing through transistor 30G, intersection 55, capacitor 60G, and wiring 53, etc.

[0091] In the following descriptions, the parts of the above-described structural example 1 and Figure 1B will be omitted. Furthermore, unless otherwise specified, the same element symbols will be used to describe layers obtained by processing the same film.

[0092] Transistors 30R and 30G are bottom-gate transistors. Furthermore, capacitors such as 60R are composed of a conductive layer 31, a conductive layer 33, and a portion of an insulating layer 34 between the conductive layers 31 and 33.

[0093] There is no insulating layer between the conductive layer 33 constituting the source or drain electrode of each transistor and the conductive layer constituting the wiring 52R, etc. Therefore, for example, the wiring 52R contacts the top surface and side surface of one of the source and drain electrodes of the transistor 30R to be electrically connected to the transistor 30R.

[0094] There is no insulating layer between the conductive layer 31 constituting the gate electrode of each transistor and the conductive layers such as wiring 51 (not shown) and wiring 53. For example, wiring 53 is in contact with the top and side surfaces of the conductive layer 31 constituting capacitor 60R, so as to be electrically connected to capacitor 60R.

[0095] In Figure 5, an insulating layer 82 is provided to cover the transistor 30R, etc., and an insulating layer 81, which serves as a planarization film, is provided on the insulating layer 82. The insulating layer 82 is preferably used as a protective film to inhibit the diffusion of impurities, etc., to the transistor 30R, etc. For example, the insulating layer 82 can be made of an inorganic insulating material, and the insulating layer 81 can be made of an organic insulating material.

[0096] The conductive layer 21 is electrically connected to the conductive layer 33 in the area overlapping with the capacitor 60R through openings provided in the insulating layers 81 and 82. By making the connection between the conductive layer 21 and the conductive layer 33 overlap with the capacitor 60R, the pixel area can be reduced, and a display device with higher resolution can be realized.

[0097] Sometimes, the cell gap of the liquid crystal element 20 is larger in the portion overlapping the connection between the conductive layer 21 and the conductive layer 33 than in other portions. Furthermore, since uneven shapes are easily formed on the top surface of the conductive layer 21 at the connection, the initial alignment of the liquid crystal 22 differs from other portions, sometimes causing light leakage. Because light leakage leads to a decrease in contrast, as shown in FIG5, it is preferable to place a light-shielding layer 42 in the area overlapping the connection. Moreover, when the liquid crystal can be sufficiently driven at the connection, it is preferable not to place the light-shielding layer 42 in that portion and instead utilize it as part of the display area, thus increasing the aperture ratio.

[0098] Here, since there is no insulating layer between the conductive layers 33 constituting wiring 52G and wiring 52R, a short circuit will occur when these conductive layers cross. Therefore, at the crossing portion 55, the two conductive layers 33 sandwiching wiring 52G and wiring 52R are electrically connected to conductive layer 31 through openings provided in insulating layer 34. Conductive layer 31 partially overlaps with wiring 52G and wiring 52R through insulating layer 34. In other words, the crossing portion 55 can also be described as having a bridge structure.

[0099] Sometimes, at the intersection 55, electrical noise from wirings 52G and 52R, overlapping with the conductive layer 31, can affect the display of the liquid crystal element 20G. However, since pixel 40 has a structure in which transistors 30G are not disposed in sub-pixels 40G, the area of ​​capacitor 60G can be larger than that of capacitor 60R. As a result, a structure less susceptible to noise can be achieved. Furthermore, since capacitor 60G transmits visible light, a high aperture ratio can be maintained even with an increased area of ​​capacitor 60G. In addition, as a method to reduce the impact of noise, it is preferable to minimize the area of ​​the intersection between wirings 52G or 52R and the conductive layer 31, thereby reducing the capacitance between them.

[0100] The above is an explanation of example 2-1 of the cross-sectional structure.

[0101] [Pixel Structure Example 2-2] Figure 6 shows a top view that differs from Figure 3A. Furthermore, Figure 3B can be used as a reference for the circuit diagram.

[0102] Figure 6 shows an example of a transistor with a top-gate structure for transistors 30R, 30G, and 30B.

[0103] [Example 2-2 of cross-sectional structure] Figure 7 shows a cross-sectional view along cut lines B3-B4 and C3-C4 in Figure 6.

[0104] For example, transistor 30R has an insulating layer 34 serving as a gate insulating layer and a conductive layer 31 serving as a gate electrode stacked on semiconductor layer 32. Furthermore, an insulating layer 82 is provided to cover the insulating layer 34 and the conductive layer 31, and a conductive layer 33 serving as a source electrode and a drain electrode is provided on the insulating layer 82. Semiconductor layer 32 includes a low-resistance region 32a in a region that does not overlap with conductive layer 31. Conductive layer 33 is electrically connected to low-resistance region 32a through an opening provided in insulating layer 82.

[0105] At the intersection 55, a pair of conductive layers 33 clamping wires 52G and 52R are electrically connected to a conductive layer 31 that intersects with wires 52G and 52R across an insulating layer 82.

[0106] The region of the semiconductor layer 32 that overlaps with the conductive layer 31 is used as a channel formation region. A pair of low-resistance regions 32a are formed sandwiching this channel formation region. The carrier concentration or impurity concentration of the low-resistance regions 32a is higher than that of the channel formation region. When an oxide semiconductor (OS) is used as the semiconductor layer 32, the low-resistance regions 32a can also be referred to as oxide conductors (OC).

[0107] [Pixel Structure Examples 2-3] Figure 8 shows a top view of a portion of its structure that differs from that of Figure 6. Furthermore, Figure 3B can be used as a reference for the circuit diagram.

[0108] The structure shown in Figure 8 differs from that shown in Figure 6 in that a portion of the low-resistance region 32a is used as wiring in the sub-pixel.

[0109] [Example 2-3 of cross-sectional structure] Figure 9 shows a cross-sectional view along cut lines B5-B6 and C5-C6 in Figure 8.

[0110] For example, focusing on transistor 30R, a portion of the low-resistance region 32a is electrically connected to wiring 52R without the help of conductive layer 33.

[0111] Focusing on transistor 30G, a portion of low-resistance region 32a intersects with wiring 52R and wiring 52G, and is electrically connected to conductive layer 33, which forms an electrode of capacitor 60G.

[0112] Thus, by using a portion of the low-resistance region 32a of the semiconductor layer 32 as wiring in the pixel, the number of contacts can be reduced, for example, compared to the structures shown in FIG6 and FIG7. Therefore, a display device with higher resolution can be realized.

[0113] [Variation Example] The above example shows a liquid crystal element with a pair of electrodes arranged in a vertical electric field above and below the liquid crystal. However, the structure of the liquid crystal element is not limited to this, and various types of liquid crystal elements can be used.

[0114] Figure 10A shows a cross-sectional schematic diagram of a display device including a liquid crystal element using FFS (Fringe Field Switching) mode.

[0115] The liquid crystal element 20R includes a conductive layer 21 used as a pixel electrode and a conductive layer 23 that overlaps the conductive layer 21 with an insulating layer 83. The conductive layer 21 has a slit-like or comb-like top surface shape.

[0116] In this structure, the overlapping portion of conductive layer 21 and conductive layer 23 forms a capacitor, which can be used as a storage capacitor. Therefore, by omitting the capacitor 60R, the area occupied by pixel 40 can be reduced, thus enabling a high-resolution display device.

[0117] In Figure 10A, the conductive layer 21 used as a pixel electrode is located on one side of the liquid crystal 22, but as shown in Figure 10B, the conductive layer 23 used as a common electrode can also be located on one side of the liquid crystal 22.

[0118] The structures of transistors 30R, 30G, and cross section 55 are not limited to these, and the structures shown above can be appropriately interchanged.

[0119] [Structure Example 3] The above shows an example where the color layer and the like are disposed on one side of the substrate 12. However, by disposing the color layer and the like on one side of the substrate 11, the structure on the side of the substrate 12 can be simplified. Furthermore, since high-position alignment is not required when bonding the substrate 11 and the substrate 12, production volume can be increased.

[0120] [Cross-sectional structure example 3-1] Figure 11 shows a cross-sectional schematic diagram. The structure shown in Figure 11 differs from the structure shown in Figure 5 in that the color layer 41R and color layer 41G are disposed on one side of the substrate 11.

[0121] In Figure 11, color layers 41R and 41G are located between insulating layers 82 and 81. Color layer 41R is configured to cover transistors 30G, 30R, 30B (not shown), and capacitor 60R. Furthermore, color layer 41G is configured to cover capacitor 60G.

[0122] A conductive layer 23 and an alignment film 24b are provided on one side of the substrate 11 of the substrate 12. Since the conductive layer 23 and the alignment film 24b can be provided throughout the display area without the need for fine processing, the structure can be simplified compared to the case of forming a color layer 41R, etc.

[0123] As described above, since the contact area between the conductive layer 21 used as a pixel electrode and other conductive layers causes light leakage, it is preferable to cover the contact area with a light-shielding layer. However, as shown in FIG5, when a light-shielding layer is provided on one side of the substrate 12, high-position alignment is required when bonding the substrate 11 and the substrate 12, thus reducing the effectiveness of providing a color layer on the substrate 11 side. Therefore, it is preferable to provide a light-shielding layer on the substrate 11 side.

[0124] In Figure 11, a light-shielding layer 57 with light-shielding properties is disposed at a position overlapping the contact portion. Since the light-shielding layer 57 is formed by processing, for example, the same conductive film as wiring 53 or wiring 51, it can be formed without increasing the manufacturing process.

[0125] When the light-shielding layer 57 is conductive, it can be formed into an island shape and electrically insulated from other wiring or electrodes. In other words, the light-shielding layer 57 can be in an electrically floating state. Alternatively, for example, the light-shielding layer 57 can be used as an electrode of the capacitor 60R. Alternatively, by overlapping a portion of the contact with a portion of the wiring 51, a portion of the wiring 51 can also serve as the light-shielding layer 57.

[0126] Figure 12 shows an example in which a light-shielding layer 58 is used instead of the light-shielding layer 57 shown in Figure 11.

[0127] A light-shielding layer 58 is disposed on the upper part of the contact portion of the conductive layer 21. The light-shielding layer 58 has the function of blocking visible light or absorbing at least a portion of visible light.

[0128] The light-shielding layer 58 can also be used as a gap spacer to maintain the distance between the substrate 11 and the substrate 12. Therefore, when an external force is applied, such as pressing the display surface or bending the display device, or when the display device is vibrated, the cell gap of the liquid crystal element 20R and the like is not easily changed, and thus interference or color change caused by the change in cell gap is not easily generated.

[0129] Preferably, the top surface of the light-shielding layer 58 is at least insulating in order to prevent short circuit between the conductive layer 21 and the conductive layer 23.

[0130] For example, the light-shielding layer 58 can be made of a resin containing pigments, dyes, or carbon black. Furthermore, when the resin is conductive, a two-layer structure can be used, in which an insulating film covers the resin after its formation. When the alignment film 24a has sufficiently high insulation and sufficiently covers the light-shielding layer 58, the top surface of the light-shielding layer 58 can also be conductive.

[0131] Alternatively, a light-shielding layer 58 can be provided on one side of the substrate 12, but in this case, a high alignment is required when bonding the substrate 11 and the substrate 12. Therefore, as shown in Figure 12, the light-shielding layer 58 is preferably provided on one side of the substrate 11.

[0132] [Structure Example 4] Figures 3A and 3B show the structure of pixel 40 connected to one gate line and three source lines, but are not limited to this. Below, examples of structures where pixel 40 is connected to three gate lines are shown.

[0133] [Pixel Structure Example 4] The pixel 40 shown in Figure 13A is connected to wiring 51G, wiring 51R and wiring 51B used as gate lines, wiring 52 used as source lines and wiring 53 used as power lines.

[0134] Figure 13A shows an example of a transistor using a bottom gate structure, similar to that in Figure 3A.

[0135] Transistor 30R, transistor 30G, transistor 30B, and capacitor 60R are arranged to overlap with color layer 41R. Capacitor 60G and capacitor 60B are arranged to overlap with color layer 41G and color layer 41B, respectively.

[0136] Figure 13B is the circuit diagram of pixel 40 shown in Figure 13A.

[0137] In transistor 30R, the gate is electrically connected to wiring 51R, one of the source and drain is electrically connected to wiring 52, and the other is electrically connected to one electrode of capacitor 60R and one electrode (pixel electrode) of liquid crystal element 20R.

[0138] In transistor 30G, the gate crosses with wiring 51R and is electrically connected to wiring 51G. One of the source and drain is electrically connected to wiring 52. The other of the source and drain crosses with wiring 51R and wiring 51G and is electrically connected to one electrode of capacitor 60G and the pixel electrode of liquid crystal element 20G.

[0139] In transistor 30B, the gate is electrically connected to wiring 51B, one of the source and drain is electrically connected to wiring 52, and the other of the source and drain is electrically connected to one electrode of capacitor 60B and the pixel electrode of liquid crystal element 20B.

[0140] The other electrode of capacitors 60R, 60G, and 60B is electrically connected to wiring 53.

[0141] [Structure Example 5] The above shows an example where one of the source and drain electrodes or the gate of transistor 30G includes a cross-section that intersects with wiring. Since electrical noise from the wiring at this cross-section affects the display, it is preferable not to include the cross-section.

[0142] [Pixel Structure Example 5-1] The structure shown in Figure 14A differs from that shown in Figure 3A in that wiring 52R is provided between transistor 30G and transistor 30B; and there is no crossover 55.

[0143] In Figure 14A, transistors 30R and 30B are disposed between wiring 52R and wiring 52B, and transistor 30G is disposed between wiring 52R and wiring 52G. Furthermore, wiring 52R includes a portion that overlaps with the color layer 41R.

[0144] In Figure 14A, wiring 52R is located along the longitudinal direction of the area where the color layer 41R is disposed. When wiring 52R has a light-shielding property, the display area of ​​sub-pixel 40R includes a non-display area (light-shielding area) extending in the longitudinal direction. Therefore, it is preferable to increase the width of the color layer 41R in the lateral direction, taking into account the width of wiring 52R.

[0145] With the above structure, except that the intersection is not required, compared with Figure 3A, the wiring 52G, wiring 52R, and wiring 52B can be arranged to be separated from each other. As a result, since the parasitic capacitance between the wirings can be reduced, it can be further applied to displays with high frame frequency.

[0146] Figure 14B is the circuit diagram of pixel 40 shown in Figure 14A.

[0147] In transistor 30R, the gate is electrically connected to wiring 51, one of the source and drain is electrically connected to wiring 52R, and the other of the source and drain is electrically connected to one electrode of capacitor 60R and one electrode (pixel electrode) of liquid crystal element 20R.

[0148] In transistor 30G, the gate is electrically connected to wiring 51, one of the source and drain is electrically connected to wiring 52G, and the other of the source and drain is electrically connected to one electrode of capacitor 60G and the pixel electrode of liquid crystal element 20G.

[0149] In transistor 30B, the gate is electrically connected to wiring 51, one of the source and drain is electrically connected to wiring 52B, and the other of the source and drain is electrically connected to one electrode of capacitor 60B and the pixel electrode of liquid crystal element 20B.

[0150] [Pixel Structure Example 5-2] Figure 15A shows a circuit diagram of the structure described below. Figure 15A shows a pixel unit 40U comprising six sub-pixels. By arranging the pixel units 40U in a matrix, a display area can be formed.

[0151] As shown in Figure 15A, a pixel unit 40U has a sub-pixel 40R and a sub-pixel 40G arranged between a wiring 52R and a wiring 52G from the left side. A wiring 52B is arranged adjacent to the wiring 52G. A sub-pixel 40B and a sub-pixel 40R are arranged between the wiring 52B and the wiring 52R. A wiring 52G is arranged adjacent to the wiring 52R. A sub-pixel 40G and a sub-pixel 40B are arranged between the wiring 52G and the wiring 52B.

[0152] Each of two adjacent sub-pixels includes at least one transistor. These two transistors are configured to overlap with one of the two color layers included in the two sub-pixels. Preferably, the transistors are configured to overlap with the color layer that absorbs shorter wavelengths of light.

[0153] For example, suppose color layer 41R transmits red, color layer 41G transmits green, and color layer 41B transmits blue. When sub-pixel 40R and sub-pixel 40G are combined, and when sub-pixel 40R and sub-pixel 40B are combined, the two transistors are arranged to overlap with the red color layer 41R. On the other hand, when sub-pixel 40G and sub-pixel 40B are combined, the two transistors are arranged to overlap with the green color layer 41G.

[0154] For example, Figure 15B shows the arrangement of each color layer 41R, color layer 41G and color layer 41B in the circuit diagram shown in Figure 15A.

[0155] [Pixel Structure Example 5-3] The pixel 40 shown in Figure 16A includes four sub-pixels with sub-pixels 40W. Pixel 40 is connected to two gate lines (wiring 51a, wiring 51b), two source lines (wiring 52a, wiring 52b), and one power line (wiring 53). In pixel 40, the four sub-pixels are arranged in a 2×2 matrix in the area surrounded by wiring 51a, wiring 51b, wiring 52a, and wiring 52b.

[0156] Subpixel 40W is, for example, a subpixel that emits white light. Therefore, it is not necessary to set a color layer in subpixel 40W.

[0157] Pixel 40 includes at least four transistors. These four transistors are used as selection transistors for each sub-pixel. The four transistors are positioned to overlap with the color layer 41R.

[0158] For example, Figure 16B shows the arrangement of the color layers in the circuit diagram shown in Figure 16A. No color layer is set in the area of ​​sub-pixel 40W.

[0159] The above is a description of various structural examples of display devices.

[0160] [Components] The components described above will be explained below.

[0161] [Substrate] The substrate included in the display panel can be made of a material with a flat surface. As the side of the substrate that extracts light from the display element, a material that allows the light to pass through is used. For example, materials such as glass, quartz, ceramic, sapphire, or organic resin can be used.

[0162] By using a thin substrate, display panels can be made lighter and thinner. Furthermore, by using a substrate whose thickness allows for flexibility, flexible display panels can be achieved. Alternatively, glass thin enough to be flexible can be used as the substrate. Alternatively, composite materials combining glass and resin materials can be used with an adhesive layer.

[0163] [transistor] The transistor includes: a conductive layer serving as a gate electrode; a semiconductor layer; a conductive layer serving as a source electrode; a conductive layer serving as a drain electrode; and an insulating layer serving as a gate insulating layer.

[0164] There are no particular limitations on the structure of the transistors included in the display device according to one embodiment of the present invention. For example, planar transistors, interleaved transistors, or anti-interleaved transistors can be used. In addition, top-gate or bottom-gate transistor structures can also be used. Furthermore, gate electrodes can be provided above and below its channel.

[0165] There are no particular restrictions on the crystallinity of the semiconductor material used for transistors; amorphous semiconductors or crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors with crystalline regions in some of their components) can be used. Using crystalline semiconductors can suppress the degradation of transistor characteristics, making them preferable.

[0166] Furthermore, as the semiconductor material used for the transistor, a metal oxide with a bandgap of 2 eV or more, preferably 2.5 eV or more, and even more preferably 3 eV or more can be used. Typically, metal oxides containing indium can be used, such as CAC-OS, which will be described later.

[0167] In addition, transistors using metal oxides with wider band gaps and lower carrier densities than silicon can retain the charge stored in a capacitor connected in series with the transistor for a long period of time due to their low off-state current.

[0168] For example, a film labeled "In-M-Zn oxide" can be used as the semiconductor layer, containing indium, zinc, and M (metals such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium).

[0169] When the metal oxide constituting the semiconductor layer is an In-M-Zn type oxide, it is preferable that the atomic ratio of the metal elements in the sputtering target used to form the In-M-Zn oxide film satisfies In≥M and Zn≥M. Preferred atomic ratios of the metal elements in this sputtering target are In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=3:1:2, In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:6, In:M:Zn=5:1:7, In:M:Zn=5:1:8, etc. Note that the atomic ratio of the formed semiconductor layer can vary within ±40% of the atomic ratio of the metal elements in the sputtering target described above.

[0170] The bottom-gate structure transistor shown in this embodiment is preferable because it reduces the number of manufacturing processes. Furthermore, by using metal oxides, the metal oxides can be formed at a lower temperature than polycrystalline silicon, and materials with low heat resistance can be used as wiring or electrode materials below the semiconductor layer and as substrate materials, thereby expanding the range of material choices. For example, a very large area glass substrate can be appropriately used.

[0171] As a semiconductor layer, a metal oxide film with a low carrier density can be used. For example, a metal oxide with a carrier density of 1×10¹⁷ / cm³ or less, preferably 1×10¹⁵ / cm³ or less, more preferably 1×10¹³ / cm³ or less, further preferably 1×10¹¹ / cm³ or less, and even more preferably less than 1×10¹⁰ / cm³ or more than 1×10⁻⁹ / cm³ can be used as the semiconductor layer. Such a metal oxide is referred to as a high-purity or substantially high-purity metal oxide. Therefore, because of its low impurity concentration and defect energy level density, it can be said to have stable properties.

[0172] Note that the present invention is not limited to the above description, and materials with appropriate compositions can be used according to the desired semiconductor characteristics and electrical characteristics (field-effect mobility, critical voltage, etc.) of the transistor. Furthermore, it is preferable to appropriately set the carrier density, impurity concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc., of the semiconductor layer to obtain the desired semiconductor characteristics of the transistor.

[0173] When the metal oxide constituting the semiconductor layer contains silicon or carbon, which are elements of Group 14, the oxygen defects in the semiconductor layer increase, causing the semiconductor layer to become n-type. Therefore, the concentration of silicon or carbon in the semiconductor layer (measured by secondary ion mass spectrometry) is set to 2×10¹⁸ atoms / cm³ or less, preferably 2×10¹⁷ atoms / cm³ or less.

[0174] In addition, carriers are sometimes generated when alkali metals and alkaline earth metals bond with metal oxides, which increases the off-state current of the transistor. Therefore, the concentration of alkali metals or alkaline earth metals in the semiconductor layer, as measured by secondary ion mass spectrometry, is set to be below 1×10¹⁸ atoms / cm³, preferably below 2×10¹⁶ atoms / cm³.

[0175] In addition, when the metal oxide constituting the semiconductor layer contains nitrogen, electrons as carriers are generated, and the carrier density increases, making it easier to form an n-type. As a result, a transistor using a metal oxide containing nitrogen tends to have a normally-on characteristic. Therefore, the nitrogen concentration in the semiconductor layer measured by secondary ion mass spectrometry is preferably 5×1018 atoms / cm3 or less.

[0176] Oxide semiconductors are classified into single-crystalline oxide semiconductors and non-single-crystalline oxide semiconductors. Examples of non-single-crystalline oxide semiconductors include 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.

[0177] The semiconductor layer of the transistor disclosed as one embodiment of the present invention may also use CAC-OS (Cloud-Aligned Composite oxide semiconductor).

[0178] The semiconductor layer of the transistor disclosed as one embodiment of the present invention may use the above non-single-crystalline oxide semiconductor or CAC-OS. In addition, as the non-single-crystalline oxide semiconductor, it is preferable to use nc-OS or CAAC-OS.

[0179] In one embodiment of the present invention, it is preferable to use CAC-OS as the semiconductor layer of the transistor. By using CAC-OS, high electrical characteristics or high reliability can be imparted to the transistor.

[0180] The semiconductor layer may also be a mixed film of two or more of a region including CAAC-OS, a region of a polycrystalline oxide semiconductor, a region of nc-OS, a region of a-like OS, and a region of an amorphous oxide semiconductor. The mixed film sometimes has, for example, a single-layer structure or a stacked structure including two or more of the above regions.

[0181] <Configuration of CAC-OS> Hereinafter, the configuration of CAC (Cloud-Aligned Composite)-OS used in the transistor disclosed as one embodiment of the present invention will be described.

[0182] CAC-OS, for example, refers to a composition in which elements are non-uniformly distributed within a metal oxide, wherein the size of the material containing the non-uniformly distributed elements is 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or approximately. Note that below, the state in which one or more metal elements are non-uniformly distributed within a metal oxide and the regions containing those metal elements are mixed is also referred to as mosaic or patch-like, wherein the size of the region is 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or approximately.

[0183] The metal oxide preferably contains at least indium. In particular, it preferably contains both indium and zinc. In addition, it may also contain one or more of the following: aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium.

[0184] For example, CAC-OS in In-Ga-Zn oxide (in particular, In-Ga-Zn oxide can be referred to as CAC-IGZO) refers to a material composed of indium oxide (hereinafter referred to as InOX1 (X1 is a real number greater than 0)) or indium zinc oxide (hereinafter referred to as InX2ZnY2OZ2 (X2, Y2 and Z2 are real numbers greater than 0)) and gallium oxide (hereinafter referred to as GaOX3 (X3 is a real number greater than 0)) or gallium zinc oxide (hereinafter referred to as GaX4ZnY4OZ4 (X4, Y4 and Z4 are real numbers greater than 0)) etc., forming a mosaic pattern, and the mosaic-shaped InOX1 or InX2ZnY2OZ2 is uniformly distributed in the film (hereinafter also referred to as cloud-like).

[0185] In other words, CAC-OS is a composite metal oxide consisting of regions with GaOX3 as the main component and regions with InX2ZnY2OZ2 or InOX1 as the main components. In this specification, for example, when the ratio of In atoms to element M in the first region is greater than that in the second region, the In concentration in the first region is higher than that in the second region.

[0186] Note that IGZO is a general term and sometimes refers to compounds containing In, Ga, Zn, and O. Typical examples include crystalline compounds represented as InGaO3(ZnO)m1 (m1 being a natural number) or In(1+x0)Ga(1-x0)O3(ZnO)m0 (-1≤x0≤1, m0 being any number).

[0187] The aforementioned crystalline compounds have single-crystal, polycrystalline, or CAAC structures. The CAAC structure is a crystalline structure in which multiple IGZO nanocrystals have c-axis orientation and are connected in a non-oriented manner on the ab plane.

[0188] On the other hand, CAC-OS is related to the material composition of metal oxides. CAC-OS refers to a material composition containing In, Ga, Zn, and O, in one part of which nanoparticle-like regions with Ga as the main component are observed, and in another part, nanoparticle-like regions with In as the main component are observed to be randomly dispersed in a mosaic pattern. Therefore, in CAC-OS, the crystal structure is a secondary factor.

[0189] CAC-OS does not contain stacked structures consisting of two or more different types of films. For example, it does not contain a structure consisting of two layers: one with In as the main component and the other with Ga as the main component.

[0190] Note that sometimes it is not possible to observe a clear boundary between regions where GaOX3 is the main component and regions where InX2ZnY2OZ2 or InOX1 is the main component.

[0191] In the case where CAC-OS contains one or more of the following elements to replace gallium: aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium, CAC-OS refers to a composition in which nanoparticle-like regions with the element as the main component are observed in one part, and nanoparticle-like regions with In as the main component are observed to be randomly dispersed in a mosaic pattern in another part.

[0192] CAC-OS can be formed, for example, by sputtering without intentionally heating the substrate. When forming CAC-OS by sputtering, one or more gases selected from inert gases (typically argon), oxygen gases, and nitrogen gases can be used as the deposition gas. Furthermore, the lower the oxygen gas flow rate in the total flow rate of the deposition gas during film formation, the better; for example, the oxygen gas flow rate ratio should be set to 0% or more and less than 30%, preferably 0% or more and less than 10%.

[0193] CAC-OS has the following characteristics: when measured using the out-of-plane method, one of the X-ray diffraction (XRD) methods, with θ / 2θ scanning, no clear peak is observed. In other words, based on X-ray diffraction, it can be determined that there is no alignment in the ab plane direction and the c-axis direction in the measurement region.

[0194] Furthermore, in the electron diffraction pattern of CAC-OS obtained by irradiating it with an electron beam with a diameter of 1 nm (also known as a nano-beam), a ring-shaped region of high brightness and multiple bright spots within this ring-shaped region were observed. Therefore, based on the electron diffraction pattern, it can be concluded that the crystal structure of CAC-OS possesses an nc (nano-crystal) structure without alignment in either the planar or cross-sectional directions.

[0195] Furthermore, for example, in CAC-OS of In-Ga-Zn oxides, based on EDX surface analysis images obtained by Energy Dispersive X-ray spectroscopy (EDX), it can be confirmed that there is a mixture of regions with GaOX3 as the main component and regions with InX2ZnY2OZ2 or InOX1 as the main components, which are unevenly distributed.

[0196] The structure of CAC-OS differs from that of IGZO compounds, where metallic elements are uniformly distributed, and thus exhibits different properties. In other words, CAC-OS has a mosaic-like structure where regions dominated by GaOX3 and InX2ZnY2OZ2 or InOX1 are separated, and the regions dominated by each element form a mosaic pattern.

[0197] Here, the conductivity of regions with InX2ZnY2OZ2 or InOX1 as the main components is higher than that of regions with GaOX3 as the main component. In other words, when carriers flow through regions with InX2ZnY2OZ2 or InOX1 as the main components, they exhibit the conductivity of metal oxides. Therefore, when regions with InX2ZnY2OZ2 or InOX1 as the main components are distributed in a cloud-like pattern within the metal oxide, a high field mobility (µ) can be achieved.

[0198] On the other hand, regions with GaOX3 as the main component have higher insulation properties than regions with InX2ZnY2OZ2 or InOX1 as the main components. In other words, when regions with GaOX3 as the main component are distributed in metal oxides, leakage current can be suppressed and good switching operation can be achieved.

[0199] Therefore, when CAC-OS is used in semiconductor devices, high on-state current (Ion) and high field-effect mobility (µ) can be achieved through the complementary effect of the insulation caused by GaOX3 and the conductivity caused by InX2ZnY2OZ2 or InOX1.

[0200] Furthermore, semiconductor components using CAC-OS exhibit high reliability. Therefore, CAC-OS is suitable for various semiconductor devices such as displays.

[0201] Because transistors with CAC-OS in the semiconductor layer have high field-effect mobility and high driving energy, using such transistors in driving circuits, typically scan line driving circuits that generate gate signals, can provide display devices with narrow bezel widths (also known as narrow bezels). Furthermore, using such transistors in signal line driving circuits that supply signals from signal lines included in the display device (especially in demultiplexers connected to the output terminals of shift registers included in the signal line driving circuits) can provide display devices with fewer wiring connections to the display device.

[0202] Furthermore, transistors with CAC-OS in the semiconductor layer do not require a laser crystallization process, unlike transistors using low-temperature polycrystalline silicon. This reduces manufacturing costs even for display devices using large-area substrates. Moreover, in large-scale display devices with high resolution, such as Ultra High Definition (also known as "4K resolution," "4K2K," or "4K") and Ultra High Definition (also known as "8K resolution," "8K4K," or "8K"), using transistors with CAC-OS in the semiconductor layer for the driving circuitry and display section allows for faster writing and reduces display defects, making it a superior option.

[0203] Alternatively, silicon can be used in semiconductors to form channels with transistors. Amorphous silicon can be used as silicon, but crystalline silicon is particularly preferred. For example, microcrystalline silicon, polycrystalline silicon, and monocrystalline silicon are preferred. In particular, polycrystalline silicon can be formed at lower temperatures than monocrystalline silicon, and its field-effect mobility is higher than that of amorphous silicon, thus polycrystalline silicon has higher reliability.

[0204] The bottom-gate transistor illustrated in this embodiment is preferable because it reduces the number of manufacturing processes. Furthermore, by using amorphous silicon, it can be formed at a lower temperature compared to polycrystalline silicon. Therefore, materials with low heat resistance can be used as materials for wiring or electrodes below the semiconductor layer and as substrate materials, thereby expanding the range of material choices. For example, a very large area glass substrate can be appropriately used. On the other hand, top-gate transistors are preferable because they easily form impurity regions in a self-aligned manner, thereby reducing characteristic inhomogeneities. In this case, polycrystalline silicon or monocrystalline silicon is particularly preferred.

[0205] [Conductive layer] Materials used as gates, sources, and drains of light-shielding transistors, and as conductive layers for various wiring and electrodes in display devices, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or alloys with the aforementioned metals as the main component. Furthermore, films containing these materials can be used in single-layer or multi-layer structures. Examples include a single-layer structure of an aluminum film containing silicon; a two-layer structure of an aluminum film stacked on a titanium film; a two-layer structure of an aluminum film stacked on a tungsten film; a two-layer structure of a copper film stacked on a copper-magnesium-aluminum alloy film; a two-layer structure of a copper film stacked on a titanium film; a two-layer structure of a copper film stacked on a tungsten film; a three-layer structure of a titanium film or titanium nitride film, an aluminum film or a copper film, and a titanium film or titanium nitride film stacked sequentially; and a three-layer structure of a molybdenum film or molybdenum nitride film, an aluminum film or a copper film, and a molybdenum film or molybdenum nitride film stacked sequentially. Additionally, oxides such as indium oxide, tin oxide, or zinc oxide can be used. In addition, using copper containing manganese can improve the control of the shape during etching, so it is better.

[0206] Furthermore, as a transparent conductive material that can be used for the gate, source, and drain of a transparent transistor, as well as for conductive layers such as wiring and electrodes constituting a display device, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and gallium-added zinc oxide, or graphene, can be used. Alternatively, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or alloy materials containing such metallic materials, can be used. Alternatively, nitrides of the metallic materials (e.g., titanium nitride) can also be used. When using metallic materials or alloy materials (or their nitrides), it is sufficient to form them thin enough to be transparent. Furthermore, a laminate of the above materials can be used as a conductive layer. For example, using a laminate of an alloy of silver and magnesium with indium tin oxide is preferred as it improves conductivity. The above materials can also be used as conductive layers constituting various wiring and electrodes of a display device, and as conductive layers included in display elements (conductive layers used as pixel electrodes and common electrodes).

[0207] As a transparent conductive material, it is preferable to use an oxide semiconductor (oxide conductor (OC)) with low resistance by including impurity elements.

[0208] [Insulating layer] As an insulating material that can be used in various insulating layers, it can be resins such as acrylic resin or epoxy resin, resins with siloxane bonds, inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, or aluminum oxide.

[0209] Examples of insulating membranes with low water permeability include silicon nitride membranes, silicon oxynitride membranes, and aluminum nitride membranes, which contain nitrogen and silicon. Silicon oxide membranes, silicon oxynitride membranes, and aluminum oxide membranes can also be used.

[0210] [Liquid Crystal Components] As liquid crystal elements, elements using the VA (Vertical Alignment) mode can be used. As vertical alignment modes, MVA (Multi-Domain Vertical Alignment), PVA (Patterned Vertical Alignment), and ASV (Advanced Super View) modes can be used.

[0211] Furthermore, various liquid crystal elements using different modes can be used as liquid crystal elements. For example, in addition to the VA mode, liquid crystal elements using TN (Twisted Nematic), IPS (In-Plane-Switching), FFS (Fringe Field Switching), ASM (Axially Symmetric Aligned Micro-cell), OCB (Optically Compensated Birefringence), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroelectric Liquid Crystal), ECB (Electrically Controlled Birefringence), guest-host modes, etc., can be used.

[0212] Furthermore, liquid crystal elements are devices that utilize the optical modulation effect of liquid crystals to control the transmission or blocking of light. The optical modulation effect of liquid crystals is controlled by the electric field applied to the liquid crystal (including transverse, longitudinal, or tilting electric fields). Liquid crystals used in liquid crystal elements can be thermotropic liquid crystals, low-molecular-weight liquid crystals, high-molecular-weight liquid crystals, polymer-dispersed liquid crystals (PDLCs), polymer network liquid crystals (PNLCs), ferroelectric liquid crystals, antiferroelectric liquid crystals, etc. These liquid crystal materials exhibit cholesteric phases, lamellae phases, cubic phases, chiral nematic phases, isotropic phases, etc., depending on the conditions.

[0213] In addition, either positive liquid crystal or negative liquid crystal can be used as the liquid crystal material, and the appropriate liquid crystal material can be selected according to the mode or design used.

[0214] Furthermore, alignment films can be applied to control the alignment of the liquid crystal. When using a lateral electric field, liquid crystals exhibiting a blue phase can also be used without an alignment film. The blue phase is a type of liquid crystal phase, referring to the phase that appears just before the cholesterol phase transforms into a homogeneous phase when the temperature of the cholesterol liquid crystal is raised. Because the blue phase only appears within a narrow temperature range, a liquid crystal composition containing several wt% or more of a chiral reagent is used in the liquid crystal layer to broaden the temperature range. Liquid crystal compositions containing a blue-phase liquid crystal and a chiral reagent have a fast response speed and are optically isotropic. Moreover, liquid crystal compositions containing a blue-phase liquid crystal and a chiral reagent do not require alignment treatment and have low viewing angle dependence. Additionally, since no alignment film is required and friction treatment is unnecessary, electrostatic damage caused by friction treatment can be prevented, and defects and breakage of the liquid crystal display device during the manufacturing process can be reduced.

[0215] In addition, transmissive liquid crystal elements, reflective liquid crystal elements, or semi-transmissive liquid crystal elements can be used as liquid crystal elements.

[0216] In one embodiment of the present invention, a transmissive liquid crystal element is particularly preferred.

[0217] When using transmissive or transflective liquid crystal elements, two polarizing plates are arranged with a pair of substrates sandwiched between them. A backlight is then positioned outside the polarizing plates. The backlight can be a direct-lit backlight or an edge-illuminated backlight. Using a direct-lit backlight with LEDs (Light Emitting Diodes) facilitates local dimming, thereby improving contrast, making it preferable. Conversely, using an edge-illuminated backlight allows for a thinner module including the backlight, which is also preferable.

[0218] When the edge-illuminated backlight is turned off, one embodiment of the present invention can be used in a transparent display.

[0219] [Color Layer] Materials that can be used for colored layers include metallic materials, resin materials, and resin materials containing pigments or dyes.

[0220] [Light-shielding layer] Examples of materials suitable for use in light-shielding layers include carbon black, titanium black, metals, metal oxides, or composite oxides containing solid solutions of multiple metal oxides. The light-shielding layer can also be a film containing resin materials or a thin film containing inorganic materials such as metals. Alternatively, a laminated film containing a colored layer can be used for the light-shielding layer. For example, a laminated structure can be used consisting of a film containing a colored layer for transmitting a certain color of light and a film containing a colored layer for transmitting other colors of light. Using the same materials for the colored layer and the light-shielding layer allows for the use of the same equipment and simplifies the manufacturing process, making it preferable.

[0221] The above is a description of the components.

[0222] At least a portion of this embodiment can be implemented in combination with other embodiments described in this specification.

[0223] Implementation Method 2 Hereinafter, structural examples of an input device (touch sensor) applicable to a display device according to one embodiment of the present invention and an input / output device (touch panel) as an example of a display device according to one embodiment of the present invention will be described.

[0224] [Structure example of a touch sensor] Below, we will describe a structural example of an input device (touch sensor) with reference to the diagram.

[0225] Figure 17A shows a top view of the input device 550. The input device 550 includes multiple conductive layers 551, multiple conductive layers 552, multiple wirings 555, and multiple wirings 556 on a substrate 560. Additionally, an FPC (Flexible Printed Circuit) 557 electrically connected to each of the multiple conductive layers 551 and 552 is disposed on the substrate 560. Figure 17A also shows an example of an IC 558 disposed on the FPC 557.

[0226] Figure 17B shows an enlarged view of the area enclosed by the dotted line in Figure 17A. Conductive layer 551 has a shape in which multiple rhomboid electrode patterns are arranged in the transverse direction of the paper. The rhomboid electrode patterns arranged in a row are electrically connected to each other. Conductive layer 552 also has a shape in which multiple rhomboid electrode patterns are arranged in the longitudinal direction of the paper, and the rhomboid electrode patterns arranged in a row are electrically connected to each other. Conductive layers 551 and 552 partially overlap and intersect each other. The intersecting portions are insulated to prevent short circuits between conductive layers 551 and 552.

[0227] As shown in Figure 17C, multiple conductive layers 552 with a rhomboid shape can also be formed by connecting conductive layers 553. Island-shaped conductive layers 552 are arranged in a longitudinal direction, and adjacent conductive layers 552 are electrically connected. By adopting the above structure, conductive layers 551 and 552 can be formed in one step by processing the same conductive film. This suppresses deviations in the film thickness of these conductive layers, and suppresses deviations in the resistance and light transmittance of each electrode due to their different locations. Here, conductive layer 552 has conductive layer 553, and conductive layer 551 may also have conductive layer 553.

[0228] As shown in Figure 17D, the inner side of the rhomboid electrode pattern of conductive layers 551 and 552 shown in Figure 17B can also be cut out, leaving only the outline shape. In this case, when the width of conductive layers 551 and 552 is so narrow that the user cannot see them, conductive layers 551 and 552 can also be formed using light-shielding materials such as metal or alloy, as described later. Additionally, conductive layers 551 or 552 shown in Figure 17D can also include the aforementioned conductive layer 553.

[0229] A conductive layer 551 is electrically connected to a wiring 555. Additionally, a conductive layer 552 is electrically connected to a wiring 556. Here, one of the conductive layers 551 and 552 corresponds to the row wiring described above, and the other corresponds to the column wiring described above.

[0230] IC558 has the function of driving a touch sensor. Therefore, the signal output from IC558 is supplied to conductive layer 551 or conductive layer 552 through wiring 555 or wiring 556. In addition, the current (or potential) flowing through conductive layer 551 or conductive layer 552 is input to IC558 through wiring 555 or wiring 556.

[0231] Here, when the touch panel is constructed such that the input device 550 overlaps with the display surface of the display panel, it is preferable to use a light-transmitting conductive material as the conductive layer 551 and conductive layer 552. Furthermore, when a light-transmitting conductive material is used as the conductive layer 551 and conductive layer 552, and light from the display panel is extracted through the conductive layer 551 or conductive layer 552, it is preferable to place a conductive film containing the same conductive material as a dummy pattern between the conductive layer 551 and conductive layer 552. In this way, by using a dummy pattern to fill a portion of the gap between the conductive layer 551 and conductive layer 552, deviations in light transmittance can be reduced. As a result, brightness deviations of the light transmitted through the input device 550 can be reduced.

[0232] As transparent conductive materials, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and gallium-added zinc oxide can be used. Alternatively, graphene-containing films can also be used. Graphene-containing films can be formed, for example, by reducing a film containing graphene oxide. Reduction methods can include heating.

[0233] Alternatively, metals or alloys thinned to a light-transmitting thickness can be used. For example, metals such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or alloys containing such metals, can be used. Alternatively, nitrides of the metal or alloy (e.g., titanium nitride) can also be used. Furthermore, two or more laminated conductive films containing the aforementioned materials can be used.

[0234] Furthermore, conductive layers 551 and 552 can also be made of conductive films that are so fine that they are invisible to the user. For example, by processing such conductive films into a grid pattern (mesh pattern), both high conductivity and high visibility of the display device can be achieved. In this case, it is preferable that the conductive film has a width of 30 nm or more and 100 µm or less, more preferably 50 nm or more and 50 µm or less, and even more preferably 50 nm or more and 20 µm or less. In particular, conductive films with a pattern width of 10 µm or less are difficult for the user to see, so this is preferable.

[0235] Figures 18A to 18D illustrate, as an example, a portion of the conductive layer 551 or a portion of the conductive layer 552 enlarged. Figure 18A shows an example using a grid-like conductive film 546. In this case, it is preferable that the conductive film 546 is arranged so that the display elements included in the display device do not overlap with the conductive film 546, thus preventing light from the display elements from being blocked. In this case, it is preferable that the direction of the grid is consistent with the arrangement direction of the display elements, and that the period of the grid is an integer multiple of the period of the arrangement of the display elements.

[0236] Figure 18B shows an example of a lattice-shaped conductive film 547 processed in the manner of forming triangular openings. By adopting the above structure, the resistance can be further reduced compared to Figure 18A.

[0237] As shown in Figure 18C, a conductive film 548 with a non-periodic pattern shape can also be used. By adopting the above structure, moiré patterns generated when overlapping with the display section of the display device can be suppressed.

[0238] Conductive nanowires can also be used as conductive layers 551 and 552. Figure 18D shows an example using nanowires 549. By dispersing nanowires 549 at an appropriate density so that adjacent nanowires 549 are in contact with each other, a two-dimensional mesh is formed, which can be used as a conductive film with extremely high light transmittance. For example, nanowires with an average diameter of 1 nm or more and 100 nm or less, preferably 5 nm or more and 50 nm or less, and more preferably 5 nm or more and 25 nm or less can be used. As nanowires 549, metal nanowires such as Ag nanowires, Cu nanowires, and Al nanowires, or carbon nanotubes, can be used. For example, when using Ag nanowires, a light transmittance of 89% or more and a sheet resistance of 40 Ω / □ or more and 100 Ω / □ or less can be achieved.

[0239] The above is an explanation of a structural example of a touch sensor.

[0240] [Structure Example of a Touch Panel] There are no particular limitations on the detection elements (also referred to as sensor elements) included in the touch panel of one embodiment of the present invention. Various sensors capable of detecting the proximity or contact of detection objects such as fingers or styluses can also be used as detection elements.

[0241] For example, various methods can be used as sensors, such as electrostatic capacitive, resistive film, surface acoustic wave, infrared, optical, and pressure-sensitive types.

[0242] In this embodiment, a touch panel including an electrostatic capacitive sensing element will be used as an example for explanation.

[0243] As electrostatic capacitive types, there are surface-type electrostatic capacitive types and projection-type electrostatic capacitive types. Furthermore, projection-type electrostatic capacitive types include self-capacitance types and mutual-capacitance types. When using mutual-capacitance types, multi-point detection can be performed simultaneously, making them the preferred choice.

[0244] The touch panel of one embodiment of the present invention can adopt various structures such as a structure in which a display device and a detection element are bonded together, or a structure in which electrodes constituting the detection element are provided on one or both of the substrate supporting the display element and the opposing substrate.

[0245] [Structure Example] Figure 19A is a perspective view of a touch panel 420A according to an embodiment of the present invention. Figure 19B is a perspective view when Figure 19A is unfolded. Note that, for clarity, only typical components are shown in Figures 19A and 19B. In addition, in Figure 19B, only the outlines of a portion of the components (substrate 430, substrate 472, etc.) are shown with dashed lines.

[0246] The touch panel 420A includes an input device 410 and a display device 470 arranged in an overlapping manner. Therefore, the touch panel 420A can be referred to as an Out-Cell type touch panel.

[0247] As the display device 470, the display device shown in Embodiment 1 can be used. Therefore, the touch panel 420A is a touch panel with extremely high aperture ratio and low power consumption.

[0248] The input device 410 includes a substrate 430, electrodes 431 and 432, a plurality of wirings 441 and a plurality of wirings 442. The FPC 450 is electrically connected to the plurality of wirings 441 and the plurality of wirings 442. An IC 451 is disposed on the FPC 450.

[0249] The display device 470 includes a substrate 471 and a substrate 472 arranged opposite to each other. The display device 470 includes a display section 481 and a driving circuit section 482. Wiring 407 and the like are provided on the substrate 471. An FPC 473 is electrically connected to the wiring 407. An IC 474 is provided on the FPC 473.

[0250] Because the touch panel 420 shown in Figure 19A is equipped with FPC473, IC474, FPC450 and IC451, it can be called a touch panel module.

[0251] At least a portion of this embodiment can be implemented in combination with other embodiments described in this specification.

[0252] Implementation Method 3 Preferably, transistors with extremely low off-state current, using oxide semiconductors, are used in the pixel circuits that drive the liquid crystal elements. Alternatively, memory elements can be used in the aforementioned pixel circuits. Therefore, even when writing to the pixels is stopped while displaying a static image using the liquid crystal elements, grayscale can be maintained. That is, display can be maintained even when the frame frequency is extremely low. As a result, displays with extremely low power consumption can be achieved.

[0253] The following describes the operating modes that can be performed using liquid crystal elements, with reference to Figures 20A to 20C.

[0254] The following examples illustrate the normal mode, which operates at the usual frame frequency (typically above 30Hz and below 240Hz or above 60Hz and below 240Hz), and the idling stop (IDS) drive mode, which operates at a low frame frequency.

[0255] Idle Stop (IDS) drive mode refers to a drive method that stops rewriting image data after the image data writing process has been completed. By extending the interval between one image data write and the next image data write, the power consumption required for writing image data during that period can be saved. The frame frequency in Idle Stop (IDS) drive mode can be, for example, about 1 / 100 to 1 / 10 of that in normal operation mode.

[0256] Figures 20A, 20B, and 20C are circuit diagrams and timing diagrams illustrating the normal driving mode and the idle stop (IDS) driving mode. In Figure 20A, a liquid crystal element 601 (here, a transmissive liquid crystal element) and a pixel circuit 606 electrically connected to the liquid crystal element 601 are shown. In the pixel circuit 606 shown in Figure 20A, a signal line SL, a gate line GL, a transistor M1 connected to the signal line SL and the gate line GL, and a capacitor CsLC connected to the transistor M1 are shown.

[0257] As the transistor M1, a transistor comprising a metal oxide in the semiconductor layer is preferably used. When the transistor comprising a metal oxide has at least one of amplification, rectification, and switching functions, the metal oxide can be called a metal oxide semiconductor or oxide semiconductor, or simply OS. Hereinafter, as a typical example of a transistor, a transistor comprising an oxide semiconductor (OS transistor) will be used for explanation. Because the leakage current (off-state current) of an OS transistor in the non-conducting state is extremely low, charge can be maintained in the pixel electrode of the liquid crystal element by keeping the OS transistor in the non-conducting state.

[0258] In the circuit diagram shown in Figure 20A, the liquid crystal element LC is the leakage path for data D1. Therefore, in order to properly perform the idle stop drive, it is preferable to set the resistivity of the liquid crystal element LC to 1.0 × 10¹⁴ Ω·cm or higher.

[0259] For example, In-Ga-Zn oxides and In-Zn oxides can be applied to the channel region of the aforementioned OS transistor. The composition of the aforementioned In-Ga-Zn oxides is typically around In:Ga:Zn=1:1:1 [atomic ratio] or around In:Ga:Zn=4:2:3 [atomic ratio].

[0260] Figure 20B is a timing diagram showing the waveforms of the signals supplied to the signal line SL and the gate line GL respectively in the normal driving mode. In the normal driving mode, operation is performed at the normal frame frequency (e.g., 60Hz). Figure 20B shows periods T1 to T3. During each frame period, a scan signal is supplied to the gate line GL to perform the writing of data D1 from the signal line SL. This operation is performed regardless of whether the same data D1 is written or different data is written during periods T1 to T3.

[0261] On the other hand, Figure 20C is a timing diagram showing the waveforms of the signals supplied to the signal line SL and the gate line GL in the Idle Stop (IDS) drive mode. In the Idle Stop (IDS) drive, operation is performed at a low frame frequency (e.g., below 1 Hz). A frame period is represented by period T1, where period TW represents the data writing period, and period TRET represents the data holding period. In the Idle Stop (IDS) drive mode, a scan signal is supplied to the gate line GL during period TW to write data D1 from the signal line SL to the pixel. During period TRET, the gate line GL is fixed at a low level voltage, keeping transistor M1 in a non-conducting state to hold the written data D1 in the pixel. The low frame frequency can be, for example, 0.1 Hz or higher and below 60 Hz or 0.1 Hz or higher and below 30 Hz.

[0262] At least a portion of this embodiment can be implemented in combination with other embodiments described in this specification.

[0263] Implementation Method 4 In this embodiment, a display module that can be manufactured using one embodiment of the present invention is described.

[0264] The display module 6000 shown in Figure 21A includes a display panel 6006, a frame 6009, a printed circuit board 6010, and a battery 6011 connected to an FPC 6005, located between an upper cover 6001 and a lower cover 6002.

[0265] For example, a display device manufactured using one embodiment of the present invention can be used in display panel 6006. Display panel 6006 may include a polarizing plate and a backlight. Thus, a display module with extremely low power consumption can be realized.

[0266] The upper cover 6001 and the lower cover 6002 can be appropriately changed in shape or size according to the size of the display panel 6006.

[0267] Alternatively, the touch panel can be arranged to overlap with the display panel 6006. The touch panel can be a resistive film touch panel or a capacitive touch panel, and can be formed to overlap with the display panel 6006. Alternatively, the display panel 6006 can have the function of a touch panel without having a separate touch panel.

[0268] In addition to protecting the display panel 6006, the frame 6009 also serves as electromagnetic shielding to block electromagnetic waves generated by the operation of the printed circuit board 6010. Furthermore, the frame 6009 can also function as a heat sink.

[0269] The printed circuit board 6010 includes a power supply circuit and a signal processing circuit for outputting video signals and clock signals. The power supply circuit can be powered by an external commercial power supply or by a separately provided battery 6011. When using a commercial power supply, the battery 6011 can be omitted.

[0270] Figure 21B is a cross-sectional schematic diagram of a display module 6000 including an optical touch sensor.

[0271] The display module 6000 includes a light-emitting part 6015 and a light-receiving part 6016 disposed on a printed circuit board 6010. In addition, a pair of light guides (light guide 6017a and light guide 6017b) are included in the area surrounded by the upper cover 6001 and the lower cover 6002.

[0272] The upper cover 6001 and the lower cover 6002 can be made of materials such as plastic. Furthermore, the thickness of the upper cover 6001 and the lower cover 6002 can be reduced (e.g., by more than 0.5 mm and less than 5 mm). This allows the display module 6000 to be extremely lightweight. Moreover, since less material can be used to form the upper cover 6001 and the lower cover 6002, manufacturing costs can be reduced.

[0273] The display panel 6006 is disposed over the frame 6009 in a manner that overlaps with the printed circuit board 6010 and the battery 6011. The display panel 6006 and the frame 6009 are fixed to the light guide portion 6017a and the light guide portion 6017b.

[0274] The light 6018 emitted from the light-emitting unit 6015 passes through the light guide 6017a to the upper part of the display panel 6006, and then reaches the light-receiving unit 6016 through the light guide 6017b. For example, when the light 6018 is blocked by a detection object such as a finger or stylus, a touch operation can be detected.

[0275] Multiple light-emitting units 6015 are arranged, for example, along two adjacent edges of the display panel 6006. Multiple light-receiving units 6016 are arranged opposite to the light-emitting units 6015. Thus, information about the location of a touch operation can be obtained.

[0276] The light-emitting part 6015 can be a light source such as an LED element. In particular, the light-emitting part 6015 is preferably a light source that emits infrared light that is invisible to the user and harmless to the user.

[0277] The light-receiving part 6016 can be a photoelectric element that receives light emitted by the light-emitting part 6015 and converts it into an electrical signal. Preferably, a photodiode capable of receiving infrared light is used.

[0278] The light guides 6017a and 6017b can be components that transmit at least light 6018. By using the light guides 6017a and 6017b, the light-emitting part 6015 and the light-receiving part 6016 can be positioned on the lower side of the display panel 6006, which can suppress external light from reaching the light-receiving part 6016 and causing malfunctions of the touch sensor. A resin that absorbs visible light and transmits infrared light is particularly preferred. This further effectively suppresses malfunctions of the touch sensor.

[0279] At least a portion of this embodiment can be implemented in combination with other embodiments described in this specification.

[0280] Implementation Method 5 In this embodiment, an electronic device for display devices to which one embodiment of the present invention is applicable is described.

[0281] The display device according to one embodiment of the present invention can achieve a bright display, maintaining high visibility regardless of the intensity of external light. The display device according to one embodiment of the present invention can achieve low power consumption. Therefore, it can be appropriately applied to portable electronic devices, wearable electronic devices, e-book readers, televisions, digital signage, etc.

[0282] Figures 22A and 22B show an example of a portable information terminal 800. The portable information terminal 800 includes a housing 801, a housing 802, a display unit 803, a display unit 804, and a hinge unit 805, etc.

[0283] The outer casing 801 and the outer casing 802 are connected together by a hinge 805. The portable information terminal 800 can be transformed from the folded state shown in FIG22A to the unfolded state shown in FIG22B, where the outer casing 801 and the outer casing 802 are unfolded.

[0284] For example, document information can be displayed on display units 803 and 804, thereby enabling the portable information terminal to be used as an e-book reader. Additionally, still images or moving images can also be displayed on display units 803 and 804.

[0285] Thus, the portable information terminal 800 can be folded when carried, making it highly versatile.

[0286] Additionally, housings 801 and 802 may also include a power button, an operation button, an external connection port, a speaker, a microphone, etc.

[0287] Figure 22C shows an example of a portable information terminal. The portable information terminal 810 shown in Figure 22C 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.

[0288] The display unit 812 includes a display device according to one embodiment of the present invention.

[0289] In the portable information terminal 810, a touch sensor is included in the display unit 812. By touching the display unit 812 with a finger or stylus, various operations such as making phone calls or inputting text can be performed.

[0290] Additionally, by operating the button 813, the power can be switched on / off or the type of image displayed on the display unit 812 can be changed. For example, the email composing screen can be switched to the main menu screen.

[0291] Furthermore, by incorporating a gyroscope sensor or accelerometer within the portable information terminal 810, the orientation (vertical or horizontal) of the portable information terminal 810 can be determined, and the screen display orientation of the display unit 812 can be automatically switched. Additionally, screen display switching can also be performed by touching the display unit 812, operating the operation button 813, or inputting sound using the microphone 816.

[0292] The portable information terminal 810 has one or more functions selected from telephones, laptops, and information reading devices. Specifically, the portable information terminal 810 can be used as a smartphone. The portable information terminal 810 can, for example, perform various applications such as mobile phone calls, email, article reading and editing, music playback, animation playback, internet communication, and computer games.

[0293] Figure 22D shows an example of a camera. The camera 820 includes a housing 821, a display unit 822, operation buttons 823, a shutter button 824, etc. In addition, the camera 820 is equipped with a detachable lens 826.

[0294] The display unit 822 includes a display device according to one embodiment of the present invention.

[0295] Here, although the camera 820 has a structure that allows the lens 826 to be detached from the housing 821 and exchanged, the lens 826 and the housing can also be formed as one piece.

[0296] By pressing the shutter button 824, the camera 820 can capture still or moving images. Alternatively, the display unit 822 can be equipped with a touch panel, allowing users to take photos by touching the display unit 822.

[0297] In addition, the camera 820 may also have a separately mounted flash unit and viewfinder, etc. Furthermore, these components can also be assembled into the housing 821.

[0298] Figure 23A shows a television set 830. The television set 830 includes a display unit 831, a housing 832, a speaker 833, etc. In addition, it may also include LED lights, operation keys (including a power switch or operation switch), connection terminals, various sensors, and a microphone, etc.

[0299] The TV 830 can be operated using the remote control 834.

[0300] The broadcast waves that the television set 830 can receive include terrestrial waves and satellite waves. Furthermore, broadcast waves include analog broadcasts, digital broadcasts, and broadcasts that include both video and sound, or only sound. For example, it can receive broadcast waves transmitted in designated frequency bands within the UHF band (approximately 300MHz to 3GHz) or the VHF band (30MHz to 300MHz).

[0301] For example, by using multiple data received in multiple frequency bands, the television 830 can increase the transmission rate and thus obtain more information. Therefore, images with resolutions exceeding Full HD can be displayed on the display unit 831. For example, images with resolutions of 4K2K, 8K4K, 16K8K, or higher can be displayed.

[0302] Alternatively, the television set 830 may also employ a structure in which broadcast data is used to generate images displayed on the display unit 831, and this broadcast data is transmitted using data transmission technologies such as the Internet, LAN (Local Area Network), and Wi-Fi. In this case, the television set 830 may also omit the tuner.

[0303] Figure 23B shows a digital signage 840 disposed on a cylindrical column 842. The digital signage 840 includes a display unit 841.

[0304] The larger the display unit 841, the more information the display device can provide at once. A larger display unit 841 is more likely to attract attention, for example, it can improve the effectiveness of advertising.

[0305] By using a touch panel for the display unit 841, not only can static or dynamic images be displayed on the display unit 841, but users can also operate it intuitively, which is superior. In addition, when used to provide information such as route information or traffic information, intuitive operation can improve ease of use.

[0306] Figure 23C shows a laptop computer 850. The laptop computer 850 includes a display unit 851, a casing 852, a touchpad 853, and a connection port 854, etc.

[0307] The touchpad 853 is used as an input unit for pointing devices or digitizing tablets, and can be operated using fingers or styluses.

[0308] The touchpad 853 is equipped with a display element. As shown in FIG23C, the touchpad 853 can be used as a keyboard by displaying input keys 855 on the surface of the touchpad 853. In this case, in order to reproduce the tactile sensation by vibration when touching the input keys 855, a vibration module can also be assembled in the touchpad 853.

[0309] At least a portion of this embodiment can be implemented in combination with other embodiments described in this specification.

[0310] 10 Display devices 11 base plate 12 substrate 13 Display Section 13B Display Area 13G display area 13R display area 14 Circuits 15. Wiring 16 FPC 17 IC 20 Liquid Crystal Components 20B Liquid Crystal Element 20G LCD element 20R LCD element 21 Conductive layer 22 LCD 23 Conductive layer 24a alignment film 24b alignment film 25B light 25G optical 25R light 26 Insulation layer 30 transistors 30B transistor 30G transistor 30R transistor 31 Conductive layer 31a Conductive layer 32 Semiconductor Layer 32a Low resistance region 33 Conductive layer 34 Insulation layer 39a polarizing plate 39b polarizing plate 40 pixels 40B subpixel 40G subpixels 40R subpixel 40W subpixels 40s shaded area 40t through area 40U pixel unit 41B Color Layer 41G Color Layer 41R Color Layer 42. Light-shielding layer 51. Wiring 51a wiring 51b wiring 51B wiring 51G cabling 51R cabling 52 Wiring 52a wiring 52b wiring 52B wiring 52G cabling 52R cabling 53 Wiring 55 Intersection 57. Light-shielding layer 58. Light-shielding layer 60 capacitor 60B capacitor 60G capacitor 60R capacitor 81 Insulation layer 82 Insulation layer 83 Insulation layer 90 backlight units 407 wiring 410 Input Device 420 Touch Panel 420A Touch Panel 430 substrate 431 electrode 432 electrode 441 Wiring 442 wiring 450 FPC 451 IC 470 display device 471 base plate 472 base plate 473 FPC 474 IC 481 Display Department 482 Drive Circuit Section 546 Conductive Film 547 Conductive Film 548 conductive film 549 nanowires 550 Input Device 551 conductive layer 552 conductive layer 553 conductive layer 555 wiring 556 wiring 557 FPC 558 IC 560 base plate 601 Liquid Crystal Component 606 pixel circuit 800 Portable Information Terminal 801 casing 802 casing 803 Display Section 804 Display Section 805 Hinge 810 Portable Information Terminal 811 casing 812 Display Section 813 Operation Buttons 814 External Connection Port 815 speaker 816 microphone 817 Camera 820 camera 821 casing 822 Display Section 823 Operation Button 824 shutter button 826 lens 830 TV 831 Display Section 832 casing 833 loudspeaker 834 Remote Control 840 Digital Signboard 841 Display Department 842 pillars 850 personal computers 851 Display Unit 852 casing 853 Touchscreen 854 Connector Port 855 Input Key 6000 display module 6001 Top Cover 6002 bottom cover 6005 FPC 6006 Display Panel 6009 Framework 6010 Printed Circuit Board 6011 battery 6015 Light-emitting part 6016 Light-receiving section 6017a Light Guide Section 6017b Light Guide Section 6018 Light

[0311] none

Claims

1. A display device, comprising: First color layer; Second color layer; The first transistor includes a first semiconductor layer; A second transistor including a second semiconductor layer; a first display element; The display device further comprises: a second display element; a first capacitor electrically connected to the first display element; and a second capacitor electrically connected to the second display element; wherein the first capacitor and the first display element are both electrically connected to the first transistor, the first display element includes a region overlapping the first color layer, the second capacitor and the second display element are both electrically connected to the second transistor, and the second display element includes a region overlapping the second color layer; the display device further comprises: a first conductive layer including a first region overlapping the first semiconductor layer and a second region not overlapping the first semiconductor layer and extending along a first direction; a second conductive layer including a third region electrically connected to the first semiconductor layer and extending along a second direction intersecting the first direction; and a third conductive layer including a fourth region electrically connected to the first semiconductor layer and extending along a third direction in the same direction as the first direction; wherein the first semiconductor layer includes a region overlapping the second color layer, the second region includes a region overlapping the second color layer, the third region includes a region overlapping the second color layer and a region not overlapping the second color layer, and the fourth region includes a region not overlapping the second color layer. Furthermore, the second color layer including the region overlapping with the second display element, the second color layer including the region overlapping with the first semiconductor layer, the second color layer including the region overlapping with the second region, and the second color layer including the region overlapping with the third region are connected to each other.

2. A display device, comprising: A substrate; wherein the substrate includes a first color layer, a second color layer, a first transistor including a first semiconductor layer, a second transistor including a second semiconductor layer, a first display element, a second display element, a first capacitor electrically connected to the first display element, and a second capacitor electrically connected to the second display element, wherein the first capacitor and the first display element are both electrically connected to the first transistor, the first display element includes a region overlapping the first color layer, the second capacitor and the second display element are both electrically connected to the second transistor, and the second display element includes a region overlapping the second color layer; the display device further includes: a first conductive layer including a first region overlapping the first semiconductor layer and a second region not overlapping the first semiconductor layer and extending along a first direction; a second conductive layer including a third region electrically connected to the first semiconductor layer and extending along a second direction intersecting the first direction; and a third conductive layer including a fourth region electrically connected to the first semiconductor layer and extending along a third direction in the same direction as the first direction; wherein the first semiconductor layer includes a region overlapping the second color layer, and the second region includes a region overlapping the second color layer. The third region includes a region overlapping with the second color layer and a region not overlapping with the second color layer. The fourth region includes a region not overlapping with the second color layer. The first color layer and the second color layer are disposed on one side of the substrate. The second color layer including the region overlapping with the second display element, the second color layer including the region overlapping with the first semiconductor layer, the second color layer including the region overlapping with the second region, and the second color layer including the region overlapping with the third region are connected to each other.

3. A display device, comprising: First color layer; Second color layer; The first transistor includes a first semiconductor layer; The second transistor includes a second semiconductor layer; First display element; The display device further comprises: a second display element; a first capacitor electrically connected to the first display element; and a second capacitor electrically connected to the second display element, wherein the first capacitor and the first display element are both electrically connected to the first transistor, the first display element includes a region overlapping the first color layer, the second capacitor and the second display element are both electrically connected to the second transistor, and the second display element includes a region overlapping the second color layer. The display device also further comprises: a first conductive layer including a first region overlapping the first semiconductor layer and a second region not overlapping the first semiconductor layer and extending along a first direction; a second conductive layer including a third region electrically connected to the first semiconductor layer and extending along a second direction intersecting the first direction; and a third conductive layer including a fourth region electrically connected to the first semiconductor layer and extending along a third direction in the same direction as the first direction; wherein the first semiconductor layer includes a region overlapping the second color layer, the second region includes a region overlapping the second color layer, the third region includes a region overlapping the second color layer and a region not overlapping the second color layer, and the fourth region includes a region not overlapping the second color layer. The second color layer includes a region disposed on the first semiconductor layer, the second display element includes a region disposed on the second color layer, and the second color layer including a region overlapping with the second display element, the second color layer including a region overlapping with the first semiconductor layer, the second color layer including a region overlapping with the second region, and the second color layer including a region overlapping with the third region are connected to each other.

4. The display device as described in any one of claims 1 to 3, wherein, Both the first semiconductor layer and the second semiconductor layer comprise oxide semiconductors.

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