Electronic apparatus

Abstract

One aspect of the present invention provides a novel display device that excels in convenience or in reliability. This display device has a plurality of flexible substrates onto which a plurality of light-emitting diode chips are mounted, a substrate provided with a nitride film, and resin between the flexible substrates and the substrate provided with the nitride film. Light emitted from the light-emitting diode chips passes through the substrate provided with the nitride film.

Description

electronic equipment

[0001] One embodiment of the present invention relates to an electronic device, a display device, a manufacturing method of a display device, and an apparatus for manufacturing a display device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device, an input / output device, a driving method thereof, or a manufacturing method thereof.

[0003] In this specification, a semiconductor device refers to any device that can function by utilizing semiconductor characteristics. A transistor, a semiconductor circuit, an arithmetic device, and a memory device are examples of semiconductor devices. In addition, imaging devices, electro-optical devices, power generation devices (including thin-film solar cells and organic thin-film solar cells), and electronic devices may include semiconductor devices.

[0004] In recent years, the applications of display devices have become more diverse, and display devices are now used in, for example, mobile information terminals, home television devices (also referred to as televisions or television receivers), digital signage, and public information displays (PIDs). Typical examples of display devices include display devices equipped with light-emitting elements such as organic electroluminescence (EL) elements and light-emitting diodes (LEDs), display devices equipped with liquid crystal elements, and electronic paper that displays using an electrophoretic method. Furthermore, the brightness required of display devices is increasing year by year so that they can withstand outdoor use.

[0005] Active matrix micro LED display devices have been disclosed that use small LEDs (micro LEDs) as light emitting elements and transistors as switching elements connected to each pixel electrode (Patent Documents 1, 2, 3, and 4).

[0006] WO2020 / 065472WO2019 / 220265WO2020 / 049392WO2020 / 049397

[0007] Display devices that use micro LEDs as display elements require a long time to mount the LEDs on a circuit board, making it difficult to reduce manufacturing costs. Furthermore, the greater the number of pixels in a display device, the greater the number of LEDs that must be mounted, which increases the mounting time. Furthermore, the higher the resolution of the display device, the greater the difficulty of mounting the LEDs.

[0008] In view of the above, an object of one embodiment of the present invention is to reduce the manufacturing cost of a display device using a micro LED as a display element.Another object of one embodiment of the present invention is to provide a display device using a micro LED with a relatively large area as a display element.Another object of one embodiment of the present invention is to provide a display device that has a curved display surface and uses a micro LED with a relatively large area as a display element.

[0009] Another object of one embodiment of the present invention is to manufacture a display device using a micro LED as a display element with high yield.

[0010] An object of one embodiment of the present invention is to provide a display device with high luminance. Another object of one embodiment of the present invention is to provide a display device with high contrast. Another object of one embodiment of the present invention is to provide a display device with high response speed. Another object of one embodiment of the present invention is to provide a display device with low power consumption. Another object of one embodiment of the present invention is to provide a display device with low manufacturing cost. Another object of one embodiment of the present invention is to provide a display device with a long lifetime. Another object of one embodiment of the present invention is to provide a novel display device.

[0011] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description of the specification, drawings, and claims.

[0012] By combining multiple micro LEDs or mini LEDs as display elements, a display device for a component installed inside a vehicle can be realized. Specifically, a display with a curved display surface can be installed as a vehicle interior.

[0013] In one aspect of the present invention, a display device having a curved display surface is realized by using a flexible substrate, mounting a plurality of micro LEDs or a plurality of mini LEDs on a wiring layer provided on the flexible substrate, and then fixing the flexible substrate to a support having a curved surface, the curved surface of the support having a convex or concave shape.

[0014] To improve yield, it is preferable to fabricate a certain number of micro LEDs using a flexible substrate, and then combine multiple flexible substrates to fabricate a display device having a single display surface.

[0015] To improve reliability, a display device using multiple micro LEDs or multiple mini LEDs as display elements is sandwiched between one or two cover materials with a barrier film. Resin is placed between the cover material and the light-emitting element. By using a light-transmitting material for the cover material and resin, light emitted from the light-emitting element can be emitted in two or more directions, rather than just one.

[0016] One aspect of the present invention disclosed in this specification is a display device that includes a plurality of flexible substrates on which a plurality of light-emitting diode chips (LED chips) are mounted, a substrate on which a nitride film is provided, and a resin between the flexible substrate and the substrate on which the nitride film is provided, and light emitted from the light-emitting diode chips passes through the substrate on which the nitride film is provided.

[0017] In the above configuration, the flexible substrate, the substrate provided with the nitride film, or the resin is preferably light-transmitting. Furthermore, it is preferable that the refractive indices of these materials are similar. The substrates sandwiching the upper and lower portions for sealing are acrylic resins, which can be called cover materials. The nitride films provided on the substrates are silicon nitride films, which can also be called barrier films. It is preferable that the difference in refractive index n between the cover material and the resin be 20% or less, preferably 10% or less, and more preferably 5% or less. The refractive index refers to the value for visible light, specifically light with a wavelength of 400 nm or more and 750 nm or less, and refers to the average refractive index for light having a wavelength within the above range. The average refractive index is calculated by dividing the sum of the measured refractive index values ​​for each light having a wavelength within the above range by the number of measurement points. The refractive index of air is set to 1.

[0018] Although the flexible substrate and the substrate provided with the nitride film are called substrates, they may also be called films depending on the material and thickness.

[0019] In addition, in the above configuration, the display device disclosed in this specification can be a display device that is fixed to a support having a curved surface, and at least a part of the display surface of the display device has a curved surface. When fixed to a support having a curved surface, it is preferable to use a flexible substrate and a substrate provided with a nitride film that are thin.

[0020] In addition, in order to increase the area, multiple flexible substrates are used, and multiple micro LEDs or multiple mini LEDs are mounted on each of them, and then they are arranged in a tiled pattern to create a display device with a single display surface.

[0021] Furthermore, before arranging them in a tiled pattern, each of the multiple flexible substrates (or element layers) is cut with a laser beam. By controlling the depth with the laser beam, convex portions and concave portions are formed on the end surfaces. As the laser beam, continuous wave laser beams and pulsed wave laser beams can be used. In particular, pulsed wave laser beams are preferred because they can instantaneously emit high-energy pulsed laser beams. As pulsed wave laser beams, for example, Ar lasers, Kr lasers, excimer lasers, CO ２ Laser, YAG laser, Y２ O ３ Laser, YVO ４ Laser, YLF laser, YAlO ３ Lasers such as glass lasers, ruby ​​lasers, alexandrite lasers, Ti:sapphire lasers, copper vapor lasers, and gold vapor lasers can be used. The wavelength of the laser light is preferably 200 nm to 20 μm. For example, a CO laser with a wavelength of 10.6 μm can be used as the laser light. ２ A laser can be used. ２ The laser can process films or glass substrates made of organic or inorganic materials. When pulsed laser light is used as the laser light, the pulse width is preferably 10 ps (picoseconds) to 10 μs (microseconds), more preferably 10 ps to 1 μs, and even more preferably 10 ps to 1 ns (nanoseconds). For example, pulsed laser light with a wavelength of 532 nm and a pulse width of 1 ns or less may be used.

[0022] One embodiment of the present invention disclosed in this specification is a method for manufacturing an electronic device, including forming a first pixel region having a first light-emitting diode chip over a first substrate and forming a second pixel region having a second light-emitting diode chip over a second substrate, and arranging a plurality of first light-emitting diode chips adjacent to each other at equal intervals in a first direction in the first pixel region; aligning the second light-emitting diode chip in the second pixel region so that it coincides with the first direction and arranging the first light-emitting diode chip and the second light-emitting diode chip side by side; scanning a laser beam in a second direction intersecting the first direction to partially remove an edge of the first substrate and an edge of the first pixel region to form a convex portion; removing an edge of the second substrate and an edge of the second pixel region with the laser beam to form a concave portion; and fitting the convex portion into the concave portion to fix the first pixel region adjacent to each other.

[0023] In the above configuration, the first light emitting diode chip and the second light emitting diode chip are fixed onto the curved surface.

[0024] In the above structure, a transistor is provided between the second substrate and the first light-emitting diode chip.

[0025] In the above structure, the first substrate and the second substrate are flexible substrates.

[0026] In each of the above configurations, the first light-emitting diode chip and the second light-emitting diode chip each have a light-emitting element, and a light-emitting element emitting a first color light, a light-emitting element emitting a second color light, and a light-emitting element emitting a third color light are mounted in a matrix in the pixel region. The multiple types of light-emitting diode chips may be arranged in a stripe, mosaic, or delta pattern. One light-emitting diode chip is not limited to light-emitting elements emitting one type of light color, and one light-emitting diode chip may be provided in advance with light-emitting elements emitting three types of light colors.

[0027] One aspect of the present invention disclosed in this specification is an electronic device that includes a display device and a support, where the display device has a plurality of light-emitting diode chips, the support has a curved surface and a plurality of electrodes formed along the curved surface, and the plurality of light-emitting diode chips are electrically connected to the plurality of electrodes.

[0028] Alternatively, the electronic device may have a configuration having a wiring layer in contact with the support, and the configuration includes a display device and a support, the display device having a plurality of light-emitting diode chips and a flexible substrate on which the plurality of light-emitting diode chips are mounted, the support having a curved surface and a plurality of electrodes formed along the curved surface, the flexible substrate having a wiring layer electrically connected to the plurality of electrodes, and the plurality of light-emitting diode chips electrically connected to the plurality of electrodes via the wiring layer.

[0029] In each of the above configurations, the plurality of light-emitting diode chips each have a light-emitting element, and in the pixel region, the first light-emitting element and the second light-emitting element are adjacent to each other in a first direction, and the first light-emitting element and the third light-emitting element are adjacent to each other in a second direction, the second direction intersects with the first direction, and the first light-emitting element and the second light-emitting element emit light of different colors, and the first light-emitting element and the third light-emitting element emit light of the same color.

[0030] In each of the above configurations, by devising the arrangement of the light-emitting elements, it is possible to provide a display device that is substantially high-definition, and the configuration is such that the multiple light-emitting diode chips each have a light-emitting element, and in the pixel region, the first light-emitting element and the second light-emitting element are adjacent to each other in a first direction, the first light-emitting element and the third light-emitting element are adjacent to each other in a second direction, the fourth light-emitting element and the fifth light-emitting element are adjacent to each other in the first direction, the fourth light-emitting element and the sixth light-emitting element are adjacent to each other in the second direction, the second light-emitting element is adjacent to the fourth light-emitting element in the first direction, the second direction intersects with the first direction, the first to third light-emitting elements emit light of the same color as each other, the fourth to sixth light-emitting elements emit light of the same color as each other, and the fourth to sixth light-emitting elements emit light of a different color from the first to third light-emitting elements.

[0031] According to one embodiment of the present invention, a display device using a micro LED having a relatively large area as a display element can be realized. Alternatively, according to one embodiment of the present invention, a display device having a curved display surface and using a micro LED having a relatively large area as a display element can be realized.

[0032] According to one embodiment of the present invention, the manufacturing cost of a display device using a micro LED as a display element can be reduced. Alternatively, according to one embodiment of the present invention, a display device using a micro LED as a display element can be manufactured with a high yield.

[0033] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims.

[0034] FIGS. 1A to 1C are examples of structural cross-sectional views illustrating one embodiment of the present invention. FIGS. 2A to 2D are examples of process cross-sectional views illustrating one embodiment of the present invention. FIG. 3A is a top view illustrating a pixel region before laser irradiation, and FIG. 3B is an example of an enlarged perspective view of a portion of the pixel region. FIG. 4 is an example of a top view illustrating one embodiment of the present invention. FIG. 5A is a partial cross-sectional view of a display device illustrating one embodiment of the present invention, in which a microLED having a curved display surface is used as a display element, and FIG. 5B is a schematic cross-sectional view of the display device. FIGS. 6A1 and 6B1 are perspective views illustrating a method for manufacturing the display device, and FIGS. 6A2 and 6B2 are cross-sectional views illustrating the method for manufacturing the display device. FIGS. 7A1 and 7B1 are perspective views illustrating the method for manufacturing the display device, and FIGS. 7A2 and 7B2 are cross-sectional views illustrating the method for manufacturing the display device. FIGS. 8A1 and 8B1 are perspective views illustrating the method for manufacturing the display device, and FIGS. 8A2 and 8B2 are cross-sectional views illustrating the method for manufacturing the display device. 9A1 and 9B1 are perspective views illustrating a manufacturing method of a display device, and FIGS. 9A2 and 9B2 are cross-sectional views illustrating the manufacturing method of a display device. FIGS. 10A1 and 10B1 are perspective views illustrating a manufacturing method of a display device, and FIGS. 10A2 and 10B2 are cross-sectional views illustrating the manufacturing method of a display device. FIG. 11 is a perspective view of the device. FIG. 12 is a schematic view illustrating a configuration of the device. FIGS. 13A to 13C are cross-sectional views illustrating a manufacturing method of a display device. FIGS. 14A to 14D are cross-sectional views illustrating a manufacturing method of a display device. FIG. 15 is a schematic cross-sectional view of a display device that is a modified example. FIGS. 16A to 16C are structural examples of light-emitting elements. FIG. 17 is a diagram illustrating an example of a cross-sectional structure of a display device. FIG. 18A is a block diagram illustrating an example of a display device. FIGS. 18B to 18D are diagrams illustrating an example of a pixel circuit. FIGS. 19A to 19D are diagrams illustrating an example of a transistor. FIG. 20 is a top view illustrating a structural example of a display device. Fig. 21A to Fig. 21D are diagrams showing examples of pixels. Fig. 21E and Fig. 21F are diagrams showing examples of circuit diagrams of pixels. Fig. 22 is a diagram showing an example of the configuration inside a vehicle. Fig. 23 is a diagram showing an example of the configuration inside a vehicle. Fig. 24A and Fig. 24B are diagrams explaining one embodiment of a light-emitting device.

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various modifications can be made to the embodiments and details. Furthermore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0036] Embodiment Mode 1 In this embodiment mode, a structure in which a plurality of flexible substrates on which a plurality of light-emitting diode chips are mounted are joined together and sealed with a substrate provided with a nitride film will be described with reference to FIG.

[0037] 1A shows a cross-sectional structure of an edge of a display device, in which a flexible substrate 800 on which a plurality of light-emitting diode chips are mounted and a second substrate 801 on which a plurality of light-emitting diode chips are mounted are arranged side by side and fixed with resin 19. The outer surfaces of the substrates are sandwiched between a third substrate 12a on which a nitride film 18a is provided and a fourth substrate 12b on which a nitride film 18b is provided. The nitride film 18a can be formed on the third substrate 12a by sputtering, chemical vapor deposition (CVD), or plasma enhanced chemical vapor deposition (PECVD). Alternatively, the nitride film can be formed by atomic layer deposition (ALD), which causes less film damage. The nitride films 18a and 18b may be an insulating nitride film, an insulating oxynitride film, or an insulating nitride film, such as a silicon nitride film, an aluminum nitride film, a silicon oxynitride film, an aluminum oxynitride film, a silicon nitride oxide film, or an aluminum nitride oxide film. The thickness of the nitride films 18a and 18b is preferably 1 nm or more and 500 nm or less.

[0038] In this specification, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0039] Furthermore, a plurality of light-emitting diode chips provided on the flexible substrate 800 and a plurality of light-emitting diode chips provided on the second substrate 801 are arranged at equal intervals to form one pixel region.

[0040] How to arrange the flexible substrate 800 and the second substrate 801 will be described in detail later in Embodiment 2. Note that adjacent end faces of the flexible substrate 800 and the second substrate 801 are processed with laser light.

[0041] Although the flexible substrate 800 is illustrated as a flat surface here, when the flexible substrate 800 is fixed to a support having a curved surface, it is preferable to fix the flexible substrate 800 in a bent state along the curved surface. In this case, the entire display device (including at least the flexible substrate 800, the second substrate 801, the resin 19, the third substrate 12 a, and the fourth substrate 12 b) is fixed in a bent state.

[0042] With the above configuration, the third substrate 12a on which the nitride film 18a is provided and the fourth substrate 12b on which the nitride film 18b is provided can prevent moisture from entering from the outside, thereby improving the reliability of the display device.

[0043] Furthermore, the light-emitting direction of the light-emitting diode chip provided on the flexible substrate 800 is perpendicular to the substrate surface (two light-emitting directions opposite each other on either side of the substrate surface), and it is preferable that the resin 19 and the third substrate 12a in the path of at least one of the light-emitting directions are translucent.

[0044] Furthermore, by using a light-transmitting material for the resin 19, the third substrate 12a, and the fourth substrate 12b, which overlap the paths of two light emission directions, i.e., the first light emission path passing through the third substrate 12a and the second light emission path passing through the fourth substrate 12b, a display by light emission in two directions becomes possible. In addition, since the pixel region of the display device is light-transmitting, it can also be made into a so-called see-through display device.

[0045] 1B shows a modified example of Fig. 1A, which is an example in which one substrate is folded and sealed, unlike Fig. 1A, which shows an example in which two substrates are sealed. Fig. 1B is the same as Fig. 1A except for the part sealed with one substrate, and therefore the same reference numerals are used for the same parts as Fig. 1A.

[0046] Since sealing is performed using one substrate 12 instead of two substrates, the number of components can be reduced, leading to lower manufacturing costs. Furthermore, since sealing is performed using one substrate 12, the barrier properties are improved.

[0047] 1A and 1B, an example is shown in which an edge of a flexible substrate 810 overlaps an edge of a second substrate 811. Also, nitride films 18a and 18b are selectively provided on one folded substrate 12.

[0048] 1C , a plurality of light-emitting diode chips provided on a flexible substrate 810 and a plurality of light-emitting diode chips provided on a second substrate 811 are arranged at equal intervals to form one pixel region. An end surface of the flexible substrate 810 is a surface cut by laser light. The second substrate 811 has an element layer, and end surfaces of the element layer and the second substrate 811 are also surfaces cut by laser light. By cutting the end surface of the substrate 810 with laser light before overlapping the flexible substrate 810 and the second substrate 811, the boundary between the flexible substrate 810 and the second substrate 811 can be made inconspicuous when a display device is displayed.

[0049] Alternatively, a separate optical film may be provided. For example, when a light-emitting diode chip is used as a light-emitting element that emits ultraviolet light, a color conversion layer may be provided to realize a full-color display display device. A color conversion layer may be provided in the path of light in the light-emitting direction. When light is emitted in two directions, two color conversion layers (or color conversion films) are provided to sandwich the light-emitting diode chip from above and below. Since alignment is important, it is preferable to provide the color conversion layer (or color conversion film) between the flexible substrate 810 and the resin 19. Alternatively, a full-color display display device may be realized by using a white light-emitting diode chip and providing a color filter.

[0050] Furthermore, a circularly polarizing film may be provided as the optical film. When a circularly polarizing film is provided, it is preferably provided on one surface of the folded single substrate 12. By providing the circularly polarizing film, the boundary between the flexible substrate 810 and the second substrate 811 can be made inconspicuous when the display device is used for displaying.

[0051] This embodiment can be implemented by appropriately combining at least a part of it with other embodiment modes described in this specification.

[0052] Embodiment 2 In this embodiment, a display device which is one embodiment of the present invention and a manufacturing method thereof will be described.

[0053] First, examples of a display device that can be manufactured by a manufacturing method of a display device according to one embodiment of the present invention are shown in Fig. 4, Fig. 5A, and Fig. 5B. Fig. 4 shows an example of a top view of a display device in which two pixel regions formed on two flexible substrates (a substrate 800 and a second substrate 801) are arranged side by side, with a laser irradiation line 700 as the boundary.

[0054] Although FIG. 4 shows a planar view, the display device can also be fixed to a curved surface as shown in FIGS. 5A and 5B.

[0055] 5A, a flexible substrate 800 is fixed to a curved support 10 via a resin 19. A pixel region is formed on the flexible substrate 800, and light-emitting elements 17R, 17G, and 17B are provided in the pixel region. The light-emitting elements 17R, 17G, and 17B may be arranged in a stripe, mosaic, or delta pattern. Furthermore, light-emitting elements of four colors may be arranged by adding a white light-emitting element.

[0056] Light-emitting element 17R, light-emitting element 17G, and light-emitting element 17B are micro LED chips that emit light of different colors, and a wiring layer is provided between the micro LED chips and flexible substrate 800. The wiring layer includes electrodes 21 and 23 that are connected to light-emitting element 17R, light-emitting element 17G, and light-emitting element 17B, respectively.

[0057] Examples of flexible substrates 800 include acrylic resins, polyester resins such as PET and PEN, polyacrylonitrile resins, polyimide resins, polymethyl methacrylate resins, PC resins, PES resins, polyamide resins (nylon, aramid), polysiloxane resins, cycloolefin resins, polystyrene resins, polyamide-imide resins, polyurethane resins, polyvinyl chloride resins, polyvinylidene chloride resins, polypropylene resins, PTFE resins, and ABS resins. Materials with low linear expansion coefficients are particularly preferred, and polyamide-imide resins, polyimide resins, polyamide resins, and PET are suitable. Substrates with resin-impregnated fibers and substrates with a lower linear expansion coefficient obtained by mixing inorganic fillers into the resin can also be used.

[0058] Alternatively, a metal film can be used as the flexible substrate 800. Stainless steel or aluminum can be used as the metal film. When a metal film is used, it can withstand high heat temperatures when mounting the micro LED chip.

[0059] The flexible substrate 800 is preferably provided with a circuit for driving the light-emitting diode chip 17. The flexible substrate 800 has a circuit configured with, for example, transistors, capacitance elements, wiring, and electrodes. It is more preferable that an active matrix system in which one or more transistors are connected to each of the light-emitting elements 17R, 17G, and 17B is applied. In the pixel region, the transistors are electrically connected to the electrodes 21 and 23.

[0060] 5A illustrates an example in which each of the light-emitting elements 17R, 17G, and 17B is electrically connected to two electrodes, the electrode 21 and the electrode 23, but one embodiment of the present invention is not limited to this. Electrodes electrically connected to the pixel circuit may be formed according to the number of electrodes included in the light-emitting element 17R, the light-emitting element 17G, and the light-emitting element 17B. In this embodiment, the light-emitting element 17R, the light-emitting element 17G, and the light-emitting element 17B are illustrated as components provided on the flexible substrate 800, but the light-emitting element can be referred to as a light-emitting device. Similarly, a capacitor can be referred to as a capacitor device.

[0061] FIG. 5B shows an example cross-sectional view of the light-emitting device when light is emitted. Note that FIG. 5A corresponds to an enlarged view of the area 15 surrounded by the dashed line in FIG. 5B. Flexible substrates each having a pixel region formed thereon are arranged in a tiled pattern on the support 10, thereby enabling a larger display surface. In FIG. 5B, four light-emitting panels are fixed with resin 19. For example, to obtain a full-color display device, red, green, and blue light-emitting elements are mounted in a matrix on a single flexible substrate to form a pixel region, forming light-emitting panel 16a. Also shown are light-emitting panel 16b adjacent to light-emitting panel 16a, light-emitting panel 16c adjacent to light-emitting panel 16b, and light-emitting panel 16d adjacent to light-emitting panel 16c. Covering the four light-emitting panels makes the boundaries between the pixel regions less noticeable. Covering material 13 may be omitted if not particularly necessary. Support 10, which can also be called a housing or support member, is a member having at least a partially curved surface. When a display device is installed inside a vehicle, the support 10 is made of plastic, metal, glass, or rubber. While the support 10 is shown here as being plate-shaped, it is not particularly limited and may be any member having at least a partially curved surface. A wiring layer may be provided on the support 10, and the wiring included in the wiring layer may be electrically connected to the electrodes of the light-emitting panel. The wiring layer may include wiring, an insulating film covering the wiring, and an electrode having an opening in the insulating film and connected to the wiring through the opening. The wiring included in the wiring layer may function as auxiliary wiring, connection wiring, power supply line, signal line, or fixed potential line. The wiring of the wiring layer may be formed on the curved support 10 using known techniques. For example, the wiring layer may be provided on the support 10 using a method of selectively forming a silver paste, a transposition method, or a transfer method.

[0062] Next, a method for manufacturing a display device by arranging pixel regions provided on two flexible substrates will be described with reference to FIGS.

[0063] FIG. 2A is a schematic cross-sectional view of a stage in which laser light is irradiated onto the edge of a flexible substrate 800 after light-emitting diode chips have been mounted thereon. An element layer 820 including electrodes or transistors is formed on the flexible substrate 800 in advance, and multiple types of light-emitting diode chips are arranged at equal intervals in a matrix. For handling reasons, it is difficult to provide the element layer 820 or light-emitting diode chips on the periphery of a single flexible substrate 800, and an area without elements is present in the periphery. Therefore, laser light is irradiated to remove a portion of the element layer 820 (the edge of the pixel region) along a laser irradiation line 700 on the element layer 820. Furthermore, a portion of the flexible substrate 800 is removed by shifting the position parallel to the laser irradiation line 700 on the element layer 820. Note that, although the element layer 820 is described here as not including an LED, this is not particularly limited and may also be referred to as an element layer 820 including an LED.

[0064] The state after irradiation is shown in Fig. 2B. Then, the depth of the irradiation position of the laser light is controlled and scanning is performed, and a part of the flexible substrate 800 is removed to form a protruding part on the end face as shown in Fig. 2C.

[0065] Then, the other substrate (second substrate 801) is also irradiated with laser light, and the position of the laser irradiation line for the element layer 821 is shifted from the position of the laser irradiation line for the end face of the second substrate 801, thereby forming a recess in the end face of the second substrate 801.

[0066] Then, by combining the flexible first substrate 800 and the second substrate 801 as shown in Fig. 2D, the light-emitting diode chips can be arranged at equal intervals in one direction. The top view at this stage corresponds to Fig. 4.

[0067] By fitting the convex portions of the flexible substrate 800 into the concave portions of the second substrate 801, the bonding surface increases, and the chips can be easily fixed. Even when the distance between the light-emitting diode chips is narrow, the light-emitting diode chips can be fixed so as to be regularly arranged in one direction at equal intervals. Therefore, a large-area display device can be manufactured. The element layer 821 provided on the second substrate 801 may be configured such that wirings or electrodes included in the element layer 821 are electrically connected to wirings or electrodes included in the element layer 820 provided on the flexible substrate 800.

[0068] FIG. 3A is a top view of the display device before laser irradiation. In the display device shown in FIG. 3A , a pixel region 702, a source driver circuit portion 706, and a gate driver circuit portion 704 are provided on a flexible substrate 801, which is a first substrate. The pixel region 702, the source driver circuit portion 706, and the gate driver circuit portion 704 can be provided on an element layer provided on a flexible substrate 800. The source driver circuit portion 706 and the gate driver circuit portion 704 may be implemented as driver ICs. As shown in FIG. 3B , the pixel region 702 is provided with a plurality of light-emitting diode chips 17. The plurality of light-emitting diode chips 17 are three or four types of light-emitting elements and are arranged to realize a full-color display device. The light-emitting diode chips 17 are connected to electrodes 21 and 23 of the element layer.

[0069] Next, a manufacturing method of each display device will be described with reference to Figures 6A1 to 14D, which are perspective views and cross-sectional views of each stage of the manufacturing method of the display device.

[0070] The emission color of the LED chip that can be used in the method for manufacturing a display device according to one embodiment of the present invention is not particularly limited. For example, the method can be applied to an LED chip that emits white light. Furthermore, the method can be applied to an LED chip that emits light in the wavelength range of red, green, or blue visible light. Furthermore, the method can be applied to an LED chip that emits light in the wavelength range of near-infrared light, infrared light, or ultraviolet light. When using an LED chip that emits light in the wavelength range of near-infrared light, infrared light, or ultraviolet light, only one type of LED chip is disposed, and a color conversion layer or a color conversion film is superimposed thereon. When the color conversion layer or the color conversion film is superimposed, in this configuration, there is almost no step on the surface of the display device near the boundary between the flexible substrate 800 and the second substrate 801, which is preferable because unevenness does not occur on the surface of the color conversion layer or the color conversion film.

[0071] In this embodiment, a micro LED having a double heterojunction will be described, but the light emitting diode is not particularly limited, and for example, a micro LED having a quantum well junction or an LED using nanocolumns may also be used.

[0072] The area of ​​the light-emitting diode's light-emitting region is 1 mm ２ Preferably, 10,000 μm or less ２ More preferably, 3000 μm or less ２ More preferably, 700 μm or less ２ More preferably, the area of ​​the region is 1 μm or less. ２ More than 10 μm is preferable. ２ More than 100 μm is preferable. ２ The above is even more preferable.

[0073] Note that LEDs that can be used in the display device of one embodiment of the present invention are not limited to the above-described microLEDs. ２ Larger light emitting diodes (also called mini-LEDs) may also be used, which refer to light emitting diodes having a rectangular planar shape with at least one side of 0.1 mm or more.

[0074] The display device of this embodiment preferably includes a transistor having a channel formation region in a metal oxide layer. A transistor using a metal oxide layer can reduce power consumption. Therefore, by combining a transistor with a micro LED, a display device with extremely reduced power consumption can be realized. A micro LED refers to a light-emitting diode having a rectangular planar shape with at least one side of less than 0.1 mm.

[0075] A plurality of LED chips are formed on the LED chip substrate. An example of an LED chip substrate 900 is shown in FIGS. 6A1 and 6A2. FIG. 6A1 is a perspective view of the LED chip substrate 900, and FIG. 6A2 is a cross-sectional view taken along dashed line X1-X2 in FIG. 6A1. The LED chip has a semiconductor layer 81 having an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer, an electrode 85 functioning as a cathode, and an electrode 87 functioning as an anode, formed on a substrate 71A. A plurality of LED chips are formed on the LED chip substrate 900, and a plurality of LED chips can be fabricated by separating the LED chip substrate 900 along the LED chip sections 51A.

[0076] The substrate 71A of the LED chip substrate 900 is ground to a desired thickness (FIGS. 6B1 and 6B2). Reducing the thickness of the substrate 71A makes it easier to separate the LED chips. Alternatively, instead of grinding, the substrate 71A may be removed from the LED chip substrate 900 by irradiating it with laser light.

[0077] Grinding will be described in detail. First, the electrode 85 and electrode 87 side of the LED chip substrate 900 is bonded to the plate 903. The bonded LED chip substrate 900 and plate 903 are placed on a table 905. At this time, the plate 903 side is brought into contact with the table 905, and the LED chip substrate 900 and plate 903 are fixed to the table 905 with a vacuum chuck. Next, while rotating the table 905 within the surface of the table 905, a grinding stone 907 provided on a grinding wheel 909 is brought into contact with the substrate 71A, grinding the substrate 71A to obtain the substrate 71. The grinding wheel 909 and grinding stone 907 may be rotated during grinding.

[0078] Next, it is preferable to polish the ground surface using an abrasive (also called a slurry) to flatten the surface of the substrate 71 (FIGS. 7A1 and 7A2). Flattening the surface of the substrate 71 can prevent a decrease in yield in subsequent processes.

[0079] Furthermore, when grinding and polishing are performed, it is preferable to provide and fix a film 901 for protection on the electrode 85 and the electrode 87 side, and then perform polishing (see FIG. 6B2). After polishing, the film 901 is removed.

[0080] Next, a first film 919 is provided on the electrode 85 and electrode 87 side, and the LED chip substrate 900 and first film 919 are fixed to a first fixture 921 (FIGS. 7B1 and 7B2). The first film 919 is preferably a film that stretches when pulled (also called an expandable film). Vinyl chloride resin, silicone resin, or polyolefin resin can be used for the first film 919. The first film 919 preferably has an adhesive on its surface that weakens its adhesive strength when irradiated with light. Specifically, a film whose adhesive strength weakens when irradiated with ultraviolet light can be preferably used for the first film 919. For example, a ring-shaped jig such as that shown in FIG. 7B1 can be preferably used for the first fixture 921.

[0081] Next, scribe lines 911 are formed along the LED chip sections 51A of the LED chip substrate 900 (FIGS. 8A1 and 8A2). A machine scribing method can be used to form the scribe lines 911. In the machine scribing method, a scribe tool is pressed against the substrate 71 to mechanically form grooves (also called scribe lines or markings) in the substrate 71. A diamond blade can be used as the scribing tool.

[0082] Laser scribing may also be used to form the scribe line 911. Laser scribing is a method in which the substrate 71 is irradiated with laser light to locally heat it, and then rapidly cooled, thereby generating thermal stress that causes an altered layer in the substrate 71, thereby forming the scribe line 911. In laser scribing, the scribe line 911 may be formed on the surface of the substrate 71, or may be formed inside the surface of the substrate 71. In machine scribing, the scribing tool wears out and needs to be replaced, but laser scribing does not require replacement of the scribing tool.

[0083] Alternatively, blade dicing may be used to cut the substrate 71 along the LED chip sections 51A. Blade dicing involves rotating a blade at high speed to cut into an object, and the blade may be made of diamond. When using the blade dicing method, half-cutting may be performed, in which the cut is made partway through the thickness of the substrate 71, or full-cutting may be performed, in which the cut is made completely through the substrate 71 and the semiconductor layer 81 in the thickness direction.

[0084] Next, the LED chip substrate 900 is separated into individual LED chips. To separate the LED chips, for example, the LED chip substrate 900 is placed on a support 913 having an opening 914, and a blade 915 is driven along the scribe line 911 to separate the LED chip substrate 900 into individual LED chips ( FIGS. 8B1 and 8B2 ). Alternatively, the LED chip substrate 900 may be sandwiched between rollers, with the rollers having surfaces with different inclination angles to separate the LED chips. When separating the LED chips into individual LED chips, a protective sheet 923 (also referred to as a scribe sheet) may be provided on the substrate 71 side, and then the LED chips may be separated. The LED chip substrate 900 after separation into individual LED chips is shown in FIGS. 9A1 and 9A2 .

[0085] Next, the first film 919 is pulled to separate the LED chips 51, and the spacing between the LED chips 51 is increased ( FIGS. 9B1 and 9B2 ). Increasing the spacing between the LED chips 51 makes subsequent handling easier. To separate the LED chips 51, for example, a plate 924 with an area larger than the area where the LED chips 51 are provided is pushed up from the first film 919 side toward the LED chips 51 side, thereby pulling the first film 919 and separating the LED chips 51.

[0086] Next, the second film 927 is fixed to the second fixture 925, and the second film 927 and the second fixture 925 are provided on the substrate 71 side (FIGS. 10A1 and 10A2).

[0087] If LED chips 51 are already separated, the manufacturing process of the display device may begin with the steps shown in FIGS. 10A1 and 10A2. A second film 927 is provided on the substrate 71 side of the separated LED chips 51, and the second film 927 is fixed to a second fixture 925, allowing the process to proceed to the steps described below. In this case, providing a gap between each LED chip 51, as shown in FIGS. 10A1 and 10A2, is preferable because it increases the accuracy of the subsequent mounting process and enables the manufacturing of display devices with a high yield. Furthermore, by arranging a large number of LED chips 51 in a matrix within the second film 927, the manufacturing cost of the subsequent mounting process can be reduced.

[0088] Next, ultraviolet light is applied from the first film 919 side to separate the first film 919 and the first fixing device 921 from the LED chip 51 ( FIGS. 10B1 and 10B2 ). In the aforementioned process of separating the LED chip, the first film 919 may stretch and warp. By separating the LED chip 51 from the first film 919 and re-fixing it to the second film 927, it is possible to reduce the warp of the second film 927. Furthermore, reducing the warp of the second film 927 improves the accuracy of the subsequent mounting process, allowing display devices to be manufactured with a high yield.

[0089] It is preferable to use an elastic film as the second film 927. An elastic film deforms when a force is applied and returns to its original shape when the force is removed. A film with a high tensile modulus of elasticity can be suitably used as the second film 927. Polyamide resin, polyimide resin, or polyethylene naphthalate resin can be used as the second film 927. Furthermore, it is preferable that the second film 927 has high heat resistance. In addition, an adhesive is provided on the surface of the second film 927, allowing the LED chip substrate 900 to be fixed to the second film 927. For example, a ring-shaped jig as shown in FIG. 10B1 can be suitably used as the second fixing device 925.

[0090] Here, it is preferable to inspect the LED chips 51. A visual inspection can be used to inspect the LED chips 51. Alternatively, a voltage may be applied between the electrodes 85 and 87 to inspect the light emission state of the LED chips 51. It is preferable to acquire positional information within the second film 927 for LED chips 51 that are determined to be defective in the inspection. By acquiring the positional information of defective chips, it is possible to exclude defective chips from being mounted in the subsequent mounting process.

[0091] Next, a method for mounting the LED chip 51 on the flexible substrate 800 using a conductive paste, for example, solder, will be described.

[0092] 11 and 12 show an example of an apparatus 950 that can be used in the process of mounting LED chips 51 on a flexible substrate 800. Fig. 11 is a perspective view of the apparatus 950, and Fig. 12 is a schematic diagram showing the configuration of the apparatus 950. The apparatus 950 has a stage 951, an X-axis uniaxial robot 953, a Y-axis uniaxial robot 955, a gripping mechanism 959, a push-out mechanism 929, and a control device 961.

[0093] The stage 951 has a function of fixing the flexible substrate 800. For example, a vacuum suction mechanism can be used to fix the flexible substrate 800. The stage 951 can be moved in the X and Y directions on a plane parallel to the surface of the flexible substrate 800 by a single-axis robot 953 and a single-axis robot 955.

[0094] The gripping mechanism 959 grips the second fixture 925 that fixes the LED chip 51 and the second film 927. The gripping mechanism 959 also has a function of moving the second fixture 925 that fixes the LED chip 51 and the second film 927 to any position.

[0095] The push-out mechanism 929 moves up and down and has the function of placing the LED chip 51 on the flexible substrate 800. The push-out mechanism 929 may have a columnar (including a cylindrical or polygonal columnar) shape, and may have a shape that is tapered on the side that comes into contact with the LED chip 51. The diameter of the tip of the push-out mechanism 929 that comes into contact with the LED chip 51 is preferably smaller than the width of the LED chip 51.

[0096] The control device 961 has the function of controlling the single-axis robot 953, the single-axis robot 955, the gripping mechanism 959, and the push-out mechanism 929. In addition, the control device 961 receives position information of LED chips determined to be defective in the previous inspection process of the LED chips 51. By receiving the position information of the defective chips in the control device 961, the defective chips can be excluded from the targets for mounting.

[0097] The apparatus 950 preferably includes an alignment mechanism for the camera 957. The position of the second fixture 925 is controlled with reference to an alignment marker provided on the flexible substrate 800.

[0098] A method for mounting the LED chip 51 on the flexible substrate 800 will be described in detail with reference to FIGS.

[0099] First, the multiple LED chips 51 fixed to the second film 927 are placed opposite the flexible substrate 800. When placing the LED chips 51, it is preferable to detect the outline of the LED chips 51 using a camera 957 and obtain positional information of the LED chips 51. Based on the positional information of the LED chips 51, the gripping mechanism 959 adjusts the position of the LED chips 51 to align the electrodes 85 and 87 of the LED chips 51 with the electrodes 21 and 23 on the flexible substrate 800 ( FIG. 13A ). The gripping mechanism 959 is preferably movable in the X, Y, and θ directions on a plane parallel to the surface of the flexible substrate 800. By moving in the X, Y, and θ directions, the positions of the electrodes 85 and 87 of the LED chips 51 and the electrodes 21 and 23 on the flexible substrate 800 can be aligned with high precision.

[0100] 12 shows a configuration in which camera 957 is disposed above second film 927 and the positions of electrodes 85 and 87 of LED chip 51 are detected from above second film 927, but one aspect of the present invention is not limited to this. Furthermore, a camera (not shown) may be disposed below flexible substrate 800 and the positions of electrodes 85 and 87 of LED chip 51 and electrodes 21 and 23 on flexible substrate 800 may be detected from below flexible substrate 800.

[0101] Next, the extrusion mechanism 929 is pushed toward the flexible substrate 800 from the second film 927 side, bringing the electrodes 85 and 21, and the electrodes 87 and 23 into contact with each other. Subsequently, ultrasonic waves are applied to the extrusion mechanism 929, thereby compressing the electrodes 85 and 21, and the electrodes 87 and 23, respectively ( FIG. 13B ). Alternatively, the extrusion mechanism 929 may be heated, and the electrodes 85 and 21, and the electrodes 87 and 23 may be compressed by heat. Alternatively, the electrodes may be compressed using ultrasonic waves and heat. When the extrusion mechanism 929 is heated, it is preferable to keep the temperature of the extrusion mechanism 929 below the heat-resistant temperature of the second film 927. By keeping the temperature of the extrusion mechanism 929 below the heat-resistant temperature of the second film 927, deformation and bending of the second film 927 can be suppressed.

[0102] The extrusion mechanism 929 is connected to a unit 963 shown in Fig. 12. The unit 963 has an ultrasonic oscillator and can apply ultrasonic waves to the extrusion mechanism 929. Alternatively, the unit 963 has a heating mechanism and can apply heat to the extrusion mechanism 929. Alternatively, the unit 963 has an ultrasonic oscillator and a heating mechanism and may apply ultrasonic waves and heat to the extrusion mechanism 929. The unit 963 is connected to a control device 961, and the control device 961 controls the timing of application of ultrasonic waves and heating.

[0103] Alternatively, conductive bumps may be provided on the electrodes 21 and 23, and the LED chip 51 may be brought into contact with the bumps.

[0104] Next, the push-out mechanism 929 is separated from the second film 927 ( FIG. 13C ). Because the electrodes 85 and 21, and the electrodes 87 and 23 are respectively pressure-bonded, the LED chips 51 mounted on the electrodes 21 and 23 are separated from the second film 927. The adhesive strength of the adhesive applied to the surface of the second film 927 is preferably weaker than the pressure-bonding force between the electrodes 85 and 21, and between the electrodes 87 and 23. By using an adhesive for the second film 927 that has an adhesive strength weaker than the pressure-bonding force, the LED chips 51 can be efficiently mounted on the flexible substrate 800, and the manufacturing costs of the display device can be reduced.

[0105] If the second film 927 bends, it becomes difficult to align the electrodes 85 and 87 of the LED chip 51 with the electrodes 21 and 23 on the flexible substrate 800, which may result in poor conduction between the electrodes 85 and 87 and the electrodes 21 and 23. In one aspect of the present invention, the second film 927 is elastic, and can return to its original shape when the extrusion mechanism 929 is separated from the second film 927. By allowing the second film 927 to return to its original shape, bending of the second film 927 can be suppressed, and the positions of the electrodes 85 and 87 and the electrodes 21 and 23 can be aligned with high precision. The tensile modulus of the second film 927 is preferably 3 GPa or more and 18 GPa or less, more preferably 5 GPa or more and 16 GPa or less, and even more preferably 7 GPa or more and 14 GPa or less. By setting the tensile modulus of the second film 927 within the aforementioned range, the second film 927 stretches appropriately when the LED chip 51 is brought into contact with the electrodes 21 and 23, and the deflection of the second film 927 can be reduced when the LED chip 51 is aligned, thereby enabling display devices to be manufactured with a high yield and reducing manufacturing costs.

[0106] Next, the LED chip 51 fixed to the second film 927 is aligned with the electrodes 21 and 23 on which the LED chip 51 is not provided ( FIG. 14A ). The alignment may be performed by moving one or more of the stage 951, the gripping mechanism 959, and the extrusion mechanism 929. It is more preferable to move two or more of the stage 951, the gripping mechanism 959, and the extrusion mechanism 929. By moving two or more of the stage 951, the gripping mechanism 959, and the extrusion mechanism 929, the accuracy of alignment between the electrodes 85 and 87 of the LED chip 51 and the electrodes 21 and 23 on the flexible substrate 800 can be improved.

[0107] Next, the push-out mechanism 929 is pushed from the second film 927 side toward the flexible substrate 800, bringing electrode 85 into contact with electrode 21, and electrode 87 into contact with electrode 23. Subsequently, electrodes 85 and 21, and electrodes 87 and 23 are respectively pressure-bonded ( FIG. 14B ). The push-out mechanism 929 is then moved onto the second film 927. As a result, the LED chips 51 mounted on electrodes 21 and 23 are separated from the second film 927 ( FIG. 14C ).

[0108] The above-described operation is repeated to mount LED chips over the entire pixel region of the flexible substrate 800. Note that LED chips 51B determined to be defective in the LED chip 51 inspection process have their position information input into the control device 961, and are not mounted on the flexible substrate 800 (FIGS. 14C and 14D). By inputting the positions of the defective LED chips into the control device 961, only non-defective LED chips 51 can be mounted on the flexible substrate 800. Furthermore, a process of performing reflow in a nitrogen atmosphere after mounting to melt the solder and generate an alloy may be added.

[0109] In a method for manufacturing a display device according to one embodiment of the present invention, multiple types of LED chips 51 emitting light in different wavelength ranges can be provided on a flexible substrate 800. For example, a case will be described in which LED chips 51 emitting light in a red wavelength range (hereinafter referred to as red light), LED chips 51 emitting light in a green wavelength range (hereinafter referred to as green light), and LED chips 51 emitting light in a blue wavelength range (hereinafter referred to as blue light) are provided on the flexible substrate 800. The LED chips 51 emitting red light are mounted on the flexible substrate 800 using a second film 927 and a second fixture 925 to which the multiple LED chips 51 emitting red light are fixed. Next, the LED chips 51 are mounted on the flexible substrate 800 using a second film 927 and a second fixture 925 to which the multiple LED chips 51 emitting green light are fixed. Next, using the second film 927 to which the plurality of LED chips 51 emitting blue light are fixed and the second fixture 925, the LED chips 51 are mounted on the flexible substrate 800. In this manner, the LED chips 51 emitting red light, the LED chips 51 emitting green light, and the LED chips 51 emitting blue light can be provided on the flexible substrate 800. The order in which the types of LED chips are mounted is not particularly limited.

[0110] Although an example has been shown in which the LED chip 51 is mounted on the flexible substrate 800 via one set of the second film 927 and the second fixing device 925, one aspect of the present invention is not limited to this. A configuration in which the LED chip 51 is mounted via multiple sets of the second film 927 and the second fixing device 925 may also be used. By using such a configuration, a display device can be manufactured with high productivity. If the LED chip 51 emits monochromatic light, it functions as a subpixel, and one pixel is formed by arranging multiple types of LED chips 51, and arranging these pixels in a matrix form a pixel area. If the LED chip 51 has multiple light-emitting elements, the multiple light-emitting elements become subpixels, and one LED chip 51 forms a pixel.

[0111] In this embodiment, an example of using an extrusion mechanism 929 is shown, but this is not particularly limited to this, and an apparatus that selectively irradiates laser light to cause laser ablation and thereby mounts an LED chip over the entire pixel region of a flexible substrate 800 may also be used.

[0112] Then, in order to bond the flexible substrate 800 on which the LED chips are mounted over the entire surface of the pixel region, a resin 19 is used to fix it to a support body having a curved surface, thereby obtaining a display device.

[0113] To increase the area, multiple substrates 800 can be arranged side by side to create a display device with a pixel area of ​​m rows (m is a natural number greater than or equal to 2) and n columns (n ​​is a natural number greater than or equal to 1) as one display surface.

[0114] This completes the description of the method for manufacturing the display device.

[0115] 5B shows an example in which a light-emitting panel is provided on the convex surface side of the curved support 10, but this is not particularly limited. FIG. 15 shows a modified example of the configuration in FIG. 5B.

[0116] In the display device of Figure 15, a fifth light-emitting panel 16e, a sixth light-emitting panel 16f, a seventh light-emitting panel 16g, and an eighth light-emitting panel 16h are arranged and fixed to the concave side of the support 11. Note that, here, to avoid confusion with Figure 5B, it is called the fifth light-emitting panel 16e, but it actually corresponds to the first light-emitting panel. In the display device shown in Figure 15, the material of the cover material 13 is preferably translucent. The support 11 has a curved surface. The light-emitting direction 14b of the fifth light-emitting panel 16e is different from that of Figure 5B.

[0117] 5A , 5B , and 15 illustrate the use of a support having a uniform radius of curvature. However, the present invention is not limited to such a configuration. The entire display surface need not be curved, and the display surface may be partially flat or have a mixture of convex and concave shapes in accordance with the internal components of a vehicle (such as a dashboard, ceiling, pillars, window glass, steering wheel, seat, or inner part of a door). For example, the display device of one embodiment of the present invention can be installed on the interior wall of a vehicle, specifically, the dashboard, ceiling, or wall. The display device of one embodiment of the present invention can have a display surface with a large display area, and thus can display a relatively large map. Therefore, the display device can be used not only for vehicles but also as a navigation device for vehicles (such as an aircraft or a submarine).

[0118] Furthermore, by providing a touch sensor on the display surface, the display surface can be operated by touching with the driver's fingers. Therefore, a display device having a touch sensor can also be said to be a vehicle operation device.

[0119] Flexible substrates are more susceptible to scratches than glass substrates. In mobile information terminals where input operations are performed by touching or bringing a finger close to the terminal, it is preferable to provide a surface protection film to prevent adhesion of dirt (sebum) and scratches caused by fingernails, especially when the terminal is equipped with a touch panel.

[0120] Even for display devices installed inside a vehicle, input operations are performed by touching or approaching with a finger, so it is preferable to provide a protective film with excellent scratch resistance on the outermost surface of the display device. The protective film uses a silicon oxide film with good optical properties (high visible light transmittance or high infrared light transmittance). By providing the protective film, scratches and dirt on the film can be prevented. Furthermore, the protective film may be made of diamond-like carbon (DLC), alumina (AlOx), polyester-based materials, or polycarbonate-based materials. Note that the protective film is preferably made of a material that has high transmittance to visible light and high hardness.

[0121] Furthermore, when the protective film is formed by a coating method, it can be formed before the display device is fixed to a support having a curved surface, or after the display device is fixed to a support having a curved surface.

[0122] As described above, the structure of one embodiment of the present invention can provide a display device with high display quality. Alternatively, the structure of one embodiment of the present invention can increase the degree of freedom in designing the display device, thereby improving the design of the display device.

[0123] This embodiment can be implemented by appropriately combining at least a part of it with other embodiment modes described in this specification.

[0124] (Embodiment 3) In this embodiment, a description will be given of the configuration of the LED chip 51 shown in Embodiment 2. The LED chip 51 may also be called a light-emitting diode chip.

[0125] The LED chip includes a light-emitting diode. The configuration of the light-emitting diode is not particularly limited, and may be a metal insulator semiconductor (MIS) junction, or a homostructure, heterostructure, or double heterostructure having a PN junction or a PIN junction. It may also be a superlattice structure, or a single quantum well structure or a multi-quantum well (MQW) structure in which thin films that generate quantum effects are stacked. An LED chip using nanocolumns may also be used.

[0126] Examples of LED chips are shown in FIGS. 16A and 16B . FIG. 16A shows a cross-sectional view of the LED chip 51, and FIG. 16B shows a top view of the LED chip 51. The LED chip 51 includes a semiconductor layer 81. The semiconductor layer 81 includes an n-type semiconductor layer 75, a light-emitting layer 77 on the n-type semiconductor layer 75, and a p-type semiconductor layer 79 on the light-emitting layer 77. The p-type semiconductor layer 79 can be made of a material that has a bandgap energy larger than that of the light-emitting layer 77 and that can confine carriers to the light-emitting layer 77. The LED chip 51 also includes an electrode 85 that functions as a cathode on the n-type semiconductor layer 75, an electrode 83 that functions as a contact electrode on the p-type semiconductor layer 79, and an electrode 87 that functions as an anode on the electrode 83. The top and side surfaces of the electrode 83 are preferably covered with an insulating layer 89. The insulating layer 89 functions as a protective film for the LED chip 51.

[0127] 16C shows an example of an enlarged view of the semiconductor layer 81. As shown in Fig. 16C, the n-type semiconductor layer 75 may have an n-type contact layer 75a on the substrate 71 side and an n-type clad layer 75b on the light-emitting layer 77 side. The p-type semiconductor layer 79 may have a p-type clad layer 79a on the light-emitting layer 77 side and a p-type contact layer 79b on the p-type clad layer 79a.

[0128] The light-emitting layer 77 may have a multiple quantum well (MQW) structure in which barrier layers 77a and well layers 77b are stacked multiple times. The barrier layers 77a are preferably made of a material with a larger bandgap energy than the well layers 77b. This structure allows energy to be confined in the well layers 77b, improving quantum efficiency and the light-emitting efficiency of the LED chip 51.

[0129] In the face-up type LED chip 51, the electrode 83 can be made of a light-transmitting material, for example, ITO (In ２ O ３ -SnO ２ ), AZO(Al ２ O ３ -ZnO), In-Zn oxide (In ２ O ３ -ZnO), GZO (GeO ２ -ZnO), ICO(In２ O ３ -CeO ２ ) can be used. In the face-up type LED chip 51, light is mainly emitted toward the electrode 87 side. In the face-down type LED chip 51, the electrode 83 can be made of a light-reflecting material, such as silver, aluminum, or rhodium. In the face-down type LED chip 51, light is mainly emitted toward the substrate 71 side.

[0130] The substrate 71 is a sapphire single crystal (Al ２ O ３ ), spinel single crystal (MgAl ２ O ４ ), ZnO single crystal, LiAlO ２ Single crystal, LiGaO ２ Single crystals, oxide single crystals such as MgO single crystals, Si single crystals, SiC single crystals, GaAs single crystals, AlN single crystals, GaN single crystals, ZrB ２ In the face-down type LED chip 51, the substrate 71 is preferably made of a light-transmitting material, such as a light-transmitting sapphire single crystal.

[0131] A buffer layer (not shown) may be provided between the substrate 71 and the n-type semiconductor layer 75. The buffer layer has the function of reducing the difference in lattice constant between the substrate 71 and the n-type semiconductor layer 75.

[0132] The LED chip 51 that can be used as the light-emitting diode chip 17 preferably has a horizontal structure in which the electrodes 85 and 87 are arranged on the same surface, as shown in FIG. 16A . Providing the electrodes 85 and 87 of the LED chip 51 on the same surface facilitates connection with the electrodes 21 and 23, thereby simplifying the structure of the electrodes 21 and 23. Furthermore, the LED chip 51 that can be used as the light-emitting diode chip 17 is preferably a face-down type. By using a face-down type LED chip 51, light emitted from the LED chip 51 can be efficiently emitted toward the display surface of the display device, resulting in a display device with high brightness. A commercially available LED chip may be used as the LED chip 51.

[0133] To obtain white light emission, a phosphor layer is used. The phosphor contained in the phosphor layer can be an organic resin layer on which a phosphor is printed or painted, or an organic resin layer mixed with a phosphor. The phosphor layer can be made of a material that is excited by light emitted from the LED chip 51 and emits light of a color complementary to the color of light emitted by the LED chip 51. With this configuration, the light emitted by the light-emitting diode chip 17 and the light emitted by the phosphor are combined, allowing white light to be emitted from the phosphor layer.

[0134] For example, by using an LED chip 51 that emits blue light and a phosphor that emits yellow light, which is the complementary color of blue, it is possible to achieve a configuration in which white light is emitted from the phosphor layer. A typical example of the LED chip 51 that can emit blue light is a diode made of a group 13 nitride-based compound semiconductor, and one example is In ｘ Al ｙ Ga １−ｘ−ｙ There is a diode having a GaN system represented by the formula N (x is 0 or more and 1 or less, y is 0 or more and 1 or less, x + y is 0 or more and 1 or less). A typical example of a phosphor that is excited by blue light and emits yellow light is Y ３ Al ５ O １２ :Ce(YAG:Ce), (Ba, Sr, Mg) ２ SiO ４ : Eu, Mn.

[0135] For example, an LED chip 51 that emits blue-green light and a phosphor that emits red light, which is the complementary color of blue-green, may be used, and white light may be emitted from the phosphor layer.

[0136] The phosphor layer may have a plurality of types of phosphors, and each of the phosphors may emit light of a different color. For example, a configuration in which white light is emitted from the phosphor layer may be achieved by using an LED chip 51 that emits blue light, a phosphor that emits red light, and a phosphor that emits green light. A representative example of a phosphor that is excited by blue light and emits red light is (Ca,Sr)S:Eu,Sr ２ Si ７ Al ３ ON １３A typical example of a phosphor that is excited by blue light and emits green light is SrGa ２ S ４ : Eu, Sr ３ Si １３ Al ３ O ２ N ２１ : There is Eu.

[0137] Furthermore, a configuration can be achieved in which white light is emitted from the phosphor layer by using an LED chip 51 that emits near-ultraviolet light or violet light, a phosphor that emits red light, a phosphor that emits green light, and a phosphor that emits blue light. A representative example of a phosphor that is excited by near-ultraviolet light or violet light and emits red light is (Ca,Sr)S:Eu,Sr ２ Si ７ Al ３ ON １３ : Eu, La ２ O ２ A typical example of a phosphor that is excited by near-ultraviolet light or violet light and emits green light is SrGa ２ S ４ : Eu, Sr ３ Si １３ Al ３ O ２ N ２１ A typical example of a phosphor that is excited by near-ultraviolet light or violet light and emits blue light is Sr １０ (P.O. ４ ) ６ Cl ２ :Eu, (Sr, Ba, Ca) １０ (P.O. ４ ) ６ Cl ２ : There is Eu.

[0138] In addition, near-ultraviolet light has a maximum peak in the wavelength range of 200 nm to 380 nm in its emission spectrum. Furthermore, violet light has a maximum peak in the wavelength range of 380 nm to 430 nm in its emission spectrum. Furthermore, blue light has a maximum peak in the wavelength range of 430 nm to 490 nm in its emission spectrum. Furthermore, green light has a maximum peak in the wavelength range of 490 nm to 550 nm in its emission spectrum. Furthermore, yellow light has a maximum peak in the wavelength range of 550 nm to 590 nm in its emission spectrum. Furthermore, red light has a maximum peak in the wavelength range of 640 nm to 770 nm in its emission spectrum.

[0139] When the phosphor layer includes a phosphor that emits yellow light and the LED chip 51 emits blue light, the light emitted by the LED chip 51 preferably has a maximum peak in the wavelength range of 330 nm to 500 nm, more preferably 430 nm to 490 nm, and even more preferably 450 nm to 480 nm in its emission spectrum. This allows for efficient excitation of the phosphor. Furthermore, when the light emitted by the LED chip 51 has a maximum peak in the wavelength range of 430 nm to 490 nm, the blue excitation light and the yellow light from the phosphor can be mixed to produce white light. Furthermore, when the light emitted by the LED chip 51 has a maximum peak in the wavelength range of 450 nm to 480 nm, a highly pure white light can be produced.

[0140] The above is a description of an example of the configuration of the LED chip 51.

[0141] This embodiment can be implemented by appropriately combining at least a part of it with other embodiment modes described in this specification.

[0142] Embodiment 4 In this embodiment, an example of the display device illustrated in Embodiment 1, 2, or 3 will be described in detail.

[0143] FIG. 17 shows an example of a cross-sectional view of the display device 700A.

[0144] The display device 700A has a first substrate 745 and a second substrate 740 bonded together with a resin 732 .

[0145] A pixel region 702 is provided on a first substrate 745. In addition, a plurality of light-emitting elements 782 are provided in the pixel region 702.

[0146] The structure of the transistor included in the pixel region 702 is not particularly limited. A single crystal semiconductor, a polycrystalline semiconductor, a microcrystalline semiconductor, or an amorphous semiconductor can be used alone or in combination as a semiconductor layer of the transistor. Examples of semiconductor materials that can be used include silicon and germanium. Furthermore, compound semiconductors typified by silicon germanium, silicon carbide, gallium arsenide, oxide semiconductors, and nitride semiconductors, and organic semiconductors can be used.

[0147] When an organic semiconductor is used for the semiconductor layer, a low-molecular organic material having an aromatic ring or a π-electron conjugated conductive polymer can be used, such as rubrene, tetracene, pentacene, perylene diimide, tetracyanoquinodimethane, polythiophene, polyacetylene, or polyparaphenylene vinylene.

[0148] The transistor used in this embodiment preferably includes an oxide semiconductor film that is highly purified and in which oxygen vacancies are suppressed. The off-state current of the transistor can be reduced. Therefore, the retention time of an electric signal (image signal) can be increased, and the writing interval in the on state can also be set to be long. Therefore, the frequency of refresh operations can be reduced, which leads to an effect of reducing power consumption.

[0149] A transistor including an oxide semiconductor film (also referred to as an OS transistor) can operate at high speed because it has relatively high field-effect mobility. Furthermore, by using a transistor capable of operating at high speed in a pixel region, high-quality images can be provided.

[0150] A transistor using an oxide semiconductor film may be fabricated as appropriate using a known technique, and is not particularly limited. In FIG. 17 , the transistor 750 can be considered to be a type of top-gate transistor having a back gate electrode. The potential of the back gate electrode may be the same as that of the gate electrode, may be ground potential (GND potential), or may be any potential. Furthermore, the threshold voltage of the transistor can be changed by changing the potential of the back gate electrode independently of the gate electrode.

[0151] In addition, since the gate electrode and the back gate electrode are formed of conductive layers, they have a function of preventing an electric field generated outside the transistor from acting on the semiconductor layer in which the channel is formed (particularly, an electric field shielding function against static electricity). Note that the electric field shielding function can be enhanced by forming the back gate electrode larger than the semiconductor layer and covering the semiconductor layer with the back gate electrode.

[0152] 17 includes a lead wiring portion 711, a pixel region 702, and a gate driver circuit portion 704. The lead wiring portion 711 includes a signal line 710. The pixel region 702 includes a transistor 750 and a capacitor 790. The gate driver circuit portion 704 includes a transistor 752. Although not shown here, a source driver circuit portion may be provided, and the source driver circuit portion includes a transistor. The gate driver circuit portion 704 and the source driver circuit portion may not be provided over the first substrate 745, but may be implemented as ICs in other portions.

[0153] 17 includes a lower electrode formed by processing the same film as the first gate electrode of the transistor 750, and an upper electrode formed by processing the same metal oxide as the semiconductor layer. The upper electrode has low resistance, similar to the source and drain regions of the transistor 750. A portion of an insulating film functioning as the first gate insulating layer of the transistor 750 is provided between the lower and upper electrodes. That is, the capacitor 790 has a stacked structure in which an insulating film functioning as a dielectric film is sandwiched between a pair of electrodes. The upper electrode is connected to a wiring obtained by processing the same film as the source and drain electrodes of the transistor.

[0154] An insulating layer 770 is provided over the transistor 750, the transistor 752, and the capacitor 790. The insulating layer 770 functions as a planarizing film and can flatten the top surfaces of the conductive layers 772 and 774 provided over the insulating layer 770. Since the conductive layers 772 and 774 are located on the same plane and the top surfaces of the conductive layers 772 and 774 are flat, the conductive layers 772 and 774 can be easily electrically connected to the light-emitting element 782.

[0155] The conductive layers 772 and 774 are electrically connected to the light-emitting element 782 via conductive bumps 791 and 793. Fig. 17 shows a configuration in which the cathode electrode and the anode electrode of the light-emitting element 782 have different heights, and the bumps 791 and 793 also have different heights. Note that when the cathode electrode and the anode electrode of the light-emitting element 782 have the same height, the bumps 791 and 793 can have approximately the same height.

[0156] 17 , the transistor 750 included in the pixel region 702 is preferably provided so as to overlap under the conductive layer 772. By providing a region where the transistor 750, particularly the channel formation region, and the conductive layer 772 overlap, light emitted from the light-emitting element 782 and external light can be prevented from reaching the transistor 750, and fluctuations in the electrical characteristics of the transistor 750 can be suppressed.

[0157] The transistor 750 in the pixel region 702 and the transistor 752 in the gate driver circuit portion 704 may have different structures. For example, a top-gate transistor may be used in one of them, and a bottom-gate transistor may be used in the other. Note that the source driver circuit portion is similar to the gate driver circuit portion 704.

[0158] The signal line 710 is formed of the same conductive film as the source and drain electrodes of the transistors 750 and 752. In this case, it is preferable to use a low-resistance material typified by a material containing copper, because this reduces signal delay due to wiring resistance and enables display on a large screen.

[0159] Since a flexible substrate is used for the first substrate 745, an insulating layer having a barrier property against water or hydrogen is preferably provided between the first substrate 745 and the transistor 750. The transistor 750 or the capacitor 790 is provided on the insulating layer 744 provided on the resin layer 743. The resin layer 743 and the first substrate 745 are bonded to each other by the adhesive layer 742. The resin layer 743 is preferably thinner than the first substrate 745.

[0160] The second substrate 740 is bonded to the resin 732. A resin film can be used as the second substrate 740. Alternatively, the second substrate 740 may be an optical member (for example, a scattering plate), an input device such as a touch sensor panel, or a configuration in which two or more of these are stacked.

[0161] Furthermore, a light-shielding layer 738, a coloring layer 736, and a phosphor layer 797 are provided on the second substrate 740 side. The coloring layer 736 is provided on the light-emitting element 782. The phosphor layer 797 is provided between the light-emitting element 782 and the coloring layer 736. The phosphor layer 797, the light-emitting element 782, and the coloring layer 736 have overlapping regions. As shown in FIG. 17 , it is preferable that the end of the phosphor layer 797 is located outside the end of the light-emitting element 782, and the end of the coloring layer 736 is located outside the end of the phosphor layer 797. This configuration can suppress light leakage into adjacent pixels and color mixing between pixels. Furthermore, providing the light-shielding layer 738 between adjacent coloring layers 736 reduces reflection of external light, resulting in a display device with high contrast.

[0162] For example, by configuring the phosphor layer 797 to include a phosphor that emits yellow light and the light-emitting element 782 to emit blue light, white light is emitted from the phosphor layer 797. Light emitted by the light-emitting element 782 provided in a region overlapping with the coloring layer 736 that transmits red light passes through the phosphor layer 797 and the coloring layer 736 and is emitted to the display surface side as red light. Similarly, light emitted by the light-emitting element 782 provided in a region overlapping with the coloring layer 736 that transmits green light is emitted as green light. Light emitted by the light-emitting element 782 provided in a region overlapping with the coloring layer 736 that transmits blue light is emitted as blue light. This allows color display using one type of light-emitting element 782. Furthermore, since only one type of light-emitting element 782 is used in the display device, the manufacturing process can be simplified. That is, one embodiment of the present invention can provide a display device that has high luminance and contrast, a fast response speed, and low power consumption at low manufacturing cost.

[0163] For example, the phosphor layer 797 may have a phosphor that emits red light, and the light emitting element 782 may emit blue-green light, so that white light is emitted from the phosphor layer 797 .

[0164] Furthermore, the phosphor layer 797 may have a phosphor that emits red light, a phosphor that emits green light, and a phosphor that emits blue light, and the light-emitting element 782 may be configured to emit near-ultraviolet light or purple light, so that white light is emitted from the phosphor layer 797.

[0165] 17 includes a light-emitting element 782. As the light-emitting element 782, it is preferable to use a face-down type LED chip.

[0166] The colored layer 736 is provided at a position overlapping the light-emitting element 782, and the light-shielding layer 738 is provided at a position overlapping an end of the colored layer 736, in the lead-out wiring portion 711, and in the gate driver circuit portion 704. The spaces between the phosphor layer 797, the colored layer 736, and the light-shielding layer 738 and the light-emitting element 782 are filled with resin 732.

[0167] The resin layer 795 is provided adjacent to the light emitting element 782. The resin layer 795 is preferably provided between adjacent light emitting elements 782.

[0168] The thin films (insulating films, semiconductor films, conductive films) constituting the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, or an atomic layer deposition (ALD) method. The CVD method may be a plasma enhanced chemical vapor deposition (PECVD) method or a thermal CVD method. An example of the thermal CVD method is a metal organic chemical vapor deposition (MOCVD) method.

[0169] In addition, for forming thin films (insulating films, semiconductor films, conductive films) that constitute display devices, spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, and knife coating can be used.

[0170] Furthermore, when processing thin films that constitute a display device, they can be processed using a photolithography method. Alternatively, island-shaped thin films may be formed by a film formation method using a masking mask. Alternatively, thin films may be processed by a nanoimprint method, a sandblasting method, or a lift-off method. There are, for example, two photolithography methods: one is a method in which a photosensitive resist material is applied to the thin film to be processed, exposed to light through a photomask, and developed to form a resist mask, and the thin film is processed by etching, and the resist mask is then removed. The other is a method in which a photosensitive thin film is formed, and then exposed and developed to process the thin film into a desired shape.

[0171] In photolithography, the light used for exposure may be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. Alternatively, ultraviolet light, KrF laser light, or ArF laser light may be used. Exposure may also be performed by immersion exposure technology. Extreme ultraviolet light (EUV) or X-rays may also be used as the light used for exposure. An electron beam may also be used instead of the light used for exposure. Extreme ultraviolet light, X-rays, or an electron beam are preferred because they enable extremely fine processing. When exposure is performed by scanning an electron beam, a photomask is not required.

[0172] The thin film can be etched by dry etching, wet etching, or sandblasting.

[0173] A display device having a large display surface can be realized by arranging a plurality of the above-described display devices 700A side by side. Also, a display surface having a curved surface can be realized by arranging a plurality of the above-described display devices 700A side by side on a support having a curved surface.

[0174] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0175] Embodiment 5 In this embodiment, a metal oxide (also referred to as an oxide semiconductor) that can be used for the OS transistor described in Embodiment 4 will be described.

[0176] The metal oxide used in the OS transistor preferably contains at least indium or zinc, and more preferably contains indium and zinc. For example, the metal oxide preferably contains indium, M (M is one or more selected from gallium, aluminum, yttrium, tin, silicon, boron, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt), and zinc. In particular, M is preferably one or more selected from gallium, aluminum, yttrium, and tin, and more preferably gallium.

[0177] The metal oxide can be formed by sputtering, chemical vapor deposition (CVD) such as metal organic chemical vapor deposition (MOCVD), or atomic layer deposition (ALD).

[0178] Hereinafter, an oxide containing indium (In), gallium (Ga), and zinc (Zn) will be described as an example of a metal oxide. Note that an oxide containing indium (In), gallium (Ga), and zinc (Zn) may be referred to as an In—Ga—Zn oxide.

[0179] <Classification of Crystal Structure> Examples of the crystal structure of an oxide semiconductor include amorphous (including completely amorphous), c-axis-aligned crystalline line (CAAC), nanocrystalline line (nc), cloud-aligned composite (CAC), single crystal, and polycrystalline.

[0180] The crystalline structure of a film or substrate can be evaluated using an X-ray diffraction (XRD) spectrum. For example, it can be evaluated using an XRD spectrum obtained by GIXD (Grazing-Incident XRD) measurement. The GIXD method is also called the thin film method or the Seemann-Bohlin method. In the following, the XRD spectrum obtained by GIXD measurement may be simply referred to as the XRD spectrum.

[0181] For example, in the case of a quartz glass substrate, the peak shape of the XRD spectrum is almost symmetrical. On the other hand, in the case of an In-Ga-Zn oxide film having a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical peak shape of the XRD spectrum clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, it cannot be said that the film or substrate is in an amorphous state.

[0182] Furthermore, the crystalline structure of a film or substrate can be evaluated by a diffraction pattern (also referred to as a nanobeam electron diffraction pattern) observed by nanobeam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, confirming that the quartz glass is in an amorphous state. Furthermore, a spot-like pattern is observed in the diffraction pattern of an In—Ga—Zn oxide film formed at room temperature, rather than a halo. For this reason, it is estimated that the In—Ga—Zn oxide formed at room temperature is neither single crystal nor polycrystal, nor in an amorphous state, but is in an intermediate state, and it cannot be concluded that it is in an amorphous state.

[0183] <<Structure of Oxide Semiconductor>> Note that oxide semiconductors may be classified differently from the above when focusing on their structures. For example, oxide semiconductors are classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, pseudo-amorphous-like oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0184] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0185] [CAAC-OS] A CAAC-OS is an oxide semiconductor having multiple crystalline regions, each with its c-axis aligned in a specific direction. The specific direction refers to the thickness direction of the CAAC-OS film, the normal direction to the surface where the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region having periodic atomic arrangement. If the atomic arrangement is considered as a lattice arrangement, a crystalline region is also a region with a uniform lattice arrangement. Furthermore, a CAAC-OS has a region where multiple crystalline regions are connected in the a-b plane direction, and the region may have distortion. Note that distortion refers to a portion where the lattice arrangement changes between a region with a uniform lattice arrangement and a region with another uniform lattice arrangement in a region where multiple crystalline regions are connected. In other words, a CAAC-OS is an oxide semiconductor whose c-axes are aligned and whose orientation is not clearly aligned in the a-b plane direction.

[0186] Each of the multiple crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of one minute crystal, the maximum diameter of the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of the crystalline region may be several tens of nanometers.

[0187] In an In—Ga—Zn oxide, CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium (In) and oxygen (hereinafter referred to as an In layer) and a layer containing gallium (Ga), zinc (Zn), and oxygen (hereinafter referred to as a (Ga, Zn) layer) are stacked. Note that indium and gallium are mutually substituted. Therefore, the (Ga, Zn) layer may contain indium. The In layer may contain gallium. The In layer may contain zinc. The layered structure is observed as a lattice image in a high-resolution transmission electron microscope (TEM) image, for example.

[0188] When a CAAC-OS film is subjected to structural analysis using an XRD apparatus, for example, a peak indicating c-axis orientation is detected at or near 2θ = 31° in out-of-plane XRD measurement using θ / 2θ scanning. Note that the position of the peak indicating c-axis orientation (the value of 2θ) may vary depending on the type and composition of metal elements constituting the CAAC-OS.

[0189] For example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film, and the observed spots are at positions that are point-symmetric with respect to a spot of an incident electron beam that has passed through the sample (also referred to as a direct spot).

[0190] When a crystalline region is observed from the specific direction, the lattice arrangement in the crystalline region is basically a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be a non-regular hexagon. The distortion may have a pentagonal or heptagonal lattice arrangement. In the CAAC-OS, no clear grain boundary can be identified even near the distortion. This indicates that the distortion in the lattice arrangement suppresses the formation of grain boundaries. This is thought to be because the CAAC-OS can tolerate distortion due to the lack of close-packed arrangement of oxygen atoms in the a-b plane and the change in interatomic bond distance caused by substitution of metal atoms.

[0191] Note that a crystal structure in which clear grain boundaries are observed is called polycrystalline. The grain boundaries act as recombination centers, and are likely to trap carriers, reducing the on-state current and field-effect mobility of a transistor. Therefore, CAAC-OS, in which clear grain boundaries are not observed, is one of the crystalline oxides having a crystal structure suitable for a semiconductor layer of a transistor. Note that a structure containing Zn is preferable for forming a CAAC-OS. For example, In—Zn oxide and In—Ga—Zn oxide are suitable because they can suppress the generation of grain boundaries more effectively than In oxide.

[0192] CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to crystal grain boundaries. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by the inclusion of impurities or the generation of defects, the CAAC-OS can also be said to be an oxide semiconductor with few impurities and defects (oxygen vacancies). Therefore, an oxide semiconductor having a CAAC-OS has stable physical properties. Therefore, an oxide semiconductor having a CAAC-OS is heat-resistant and highly reliable. Furthermore, the CAAC-OS is stable even against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, the use of a CAAC-OS in an OS transistor can increase the flexibility of the manufacturing process.

[0193] [nc-OS] The nc-OS has periodic atomic arrangement in a microscopic region (e.g., a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has microcrystals. Note that the size of the microcrystals is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore the microcrystals are also called nanocrystals. Furthermore, the nc-OS does not exhibit regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Therefore, depending on the analysis method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor. For example, when a structural analysis of an nc-OS film is performed using an XRD apparatus, no peak indicating crystallinity is detected in out-of-plane XRD measurement using θ / 2θ scanning. When an nc-OS film is subjected to electron diffraction (also referred to as selected-area electron diffraction) using an electron beam with a probe diameter larger than that of a nanocrystal (e.g., 50 nm or more), a diffraction pattern resembling a halo pattern is observed. On the other hand, when an nc-OS film is subjected to electron diffraction (also referred to as nanobeam electron diffraction) using an electron beam with a probe diameter close to or smaller than that of a nanocrystal (e.g., 1 nm to 30 nm), an electron diffraction pattern in which multiple spots are observed within a ring-shaped region centered on a direct spot may be obtained.

[0194] [a-Like OS] The a-like OS is an oxide semiconductor having a structure between the nc-OS and an amorphous oxide semiconductor. The a-like OS has pores or low-density regions. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS. Furthermore, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and CAAC-OS.

[0195] <<Structure of Oxide Semiconductor>> Next, the above-described CAC-OS will be described in detail. Note that the CAC-OS relates to a material structure.

[0196] [CAC-OS] CAC-OS is, for example, a material in which elements constituting a metal oxide are unevenly distributed in a size of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof. Note that hereinafter, a state in which one or more metal elements are unevenly distributed in a metal oxide and regions containing the metal elements are mixed in a size of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof, is also referred to as a mosaic or patch state.

[0197] Furthermore, the CAC-OS has a mosaic structure in which a material is separated into a first region and a second region, and the first region is distributed throughout the film (hereinafter also referred to as a cloud structure). That is, the CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0198] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In—Ga—Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in the In—Ga—Zn oxide, the first region is a region where [In] is larger than [In] in the composition of the CAC-OS film. The second region is a region where [Ga] is larger than [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is a region where [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. The second region is a region where [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

[0199] Specifically, the first region is a region whose main component is indium oxide or indium zinc oxide. The second region is a region whose main component is gallium oxide or gallium zinc oxide. In other words, the first region can be referred to as a region whose main component is In. The second region can be referred to as a region whose main component is Ga.

[0200] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0201] Furthermore, CAC-OS in In—Ga—Zn oxide refers to a structure in which a mosaic of regions containing Ga as the main component and regions containing In as the main component are randomly arranged in a material composition containing In, Ga, Zn, and O. Therefore, it is presumed that CAC-OS has a structure in which metal elements are distributed nonuniformly.

[0202] The CAC-OS can be formed by sputtering, for example, without intentionally heating the substrate. When forming the CAC-OS by sputtering, any one or more of an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. The lower the flow rate of oxygen gas relative to the total flow rate of deposition gas during deposition, the more preferable it is. For example, the flow rate of oxygen gas relative to the total flow rate of deposition gas during deposition is set to 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0203] Furthermore, for example, in the case of CAC-OS in an In—Ga—Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) can confirm that the CAC-OS has a structure in which a region containing In as a main component (first region) and a region containing Ga as a main component (second region) are unevenly distributed and mixed.

[0204] Here, the first region has higher conductivity than the second region. That is, the flow of carriers through the first region causes the metal oxide to exhibit conductivity. Therefore, the first region is distributed in a cloud-like manner in the metal oxide, thereby achieving a high field-effect mobility (μ).

[0205] On the other hand, the second region has higher insulating properties than the first region. That is, the second region is distributed in the metal oxide, thereby suppressing leakage current.

[0206] Therefore, when a CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region act complementarily, thereby providing the CAC-OS with a switching function (a function of turning on / off). In other words, a CAC-OS has a conductive function in a part of the material and an insulating function in a part of the material, and the entire material functions as a semiconductor. By separating the conductive function and the insulating function, both functions can be maximized. Therefore, by using a CAC-OS in a transistor, a high on-current (I ｏｎ ), high field-effect mobility (μ), and good switching behavior can be achieved.

[0207] Furthermore, a transistor using the CAC-OS has high reliability, and therefore, the CAC-OS is ideal for various semiconductor devices typified by display devices.

[0208] Oxide semiconductors have a variety of structures, each of which has different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, a CAC-OS, an nc-OS, and a CAAC-OS.

[0209] <Transistor Having Oxide Semiconductor> Next, a case where the oxide semiconductor is used for a transistor will be described.

[0210] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0211] For the transistor, an oxide semiconductor having a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 １７ cm −３ Below 1 × 10, preferably １５ cm −３ More preferably, 1×10 １３ cm −３ or less, more preferably 1 × 10 １１ cm −３ More preferably, 1×10 １０ cm−３ is less than 1×10 −９ cm −３ The above is the case. Note that in order to reduce the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification, a semiconductor having a low impurity concentration and a low density of defect states is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Note that an oxide semiconductor having a low carrier concentration may also be referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor.

[0212] Furthermore, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore the density of trap states may also be low.

[0213] Furthermore, charges trapped in the trap states of an oxide semiconductor take a long time to disappear and may behave like fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0214] Therefore, reducing the impurity concentration in the oxide semiconductor is effective for stabilizing the electrical characteristics of a transistor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in adjacent films. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon. Note that the impurities in the oxide semiconductor refer to, for example, elements other than the main components constituting the oxide semiconductor. For example, an element with a concentration of less than 0.1 atomic % can be considered an impurity.

[0215] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0216] When an oxide semiconductor contains silicon or carbon, which is one of Group 14 elements, defect levels are formed in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are calculated to be 2×10 １８ atoms / cm３ Below 2 × 10, preferably １７ atoms / cm ３ The following applies.

[0217] Furthermore, when an oxide semiconductor contains an alkali metal or an alkaline earth metal, defect levels are formed and carriers are generated in some cases. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal is likely to have normally-on characteristics. For this reason, when the concentration of the alkali metal or the alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 １８ atoms / cm ３ Below 2 × 10, preferably １６ atoms / cm ３ Do the following:

[0218] Furthermore, when nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor tends to have normally-on characteristics. Alternatively, when nitrogen is contained in an oxide semiconductor, trap states may be formed. As a result, the electrical characteristics of the transistor may become unstable. For this reason, the nitrogen concentration in the oxide semiconductor obtained by SIMS is set to 5×10 １９ atoms / cm ３ Less than 5×10 １８ atoms / cm ３ or less, more preferably 1 × 10 １８ atoms / cm ３ or less, more preferably 5 × 10 １７ atoms / cm ３ Do the following:

[0219] Furthermore, hydrogen contained in an oxide semiconductor may react with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. Hydrogen entering the oxygen vacancy may generate electrons as carriers. Furthermore, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. Therefore, it is preferable to reduce the amount of hydrogen in the oxide semiconductor as much as possible. Specifically, the hydrogen concentration in the oxide semiconductor obtained by SIMS is measured to be 1×10 ２０ atoms / cm ３ less than 1×10 １９ atoms / cm ３ less than 5×10 １８ atoms / cm ３ less than 1×10 １８ atoms / cm ３ Make it less than.

[0220] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0221] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0222] In this embodiment, a structural example of a transistor that can be applied to a display device of one embodiment of the present invention will be described. In particular, the case where a transistor containing silicon is used in a semiconductor layer in which a channel is formed will be described.

[0223] One embodiment of the present invention is a display device including a light-emitting device and a pixel circuit. The display device can achieve full-color display by including, for example, three types of light-emitting devices that emit red (R), green (G), and blue (B) light, respectively.

[0224] It is preferable that all transistors included in a pixel circuit that drives a light-emitting device be transistors having silicon in a semiconductor layer where a channel is formed. Examples of silicon include single crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, it is preferable to use a transistor having low temperature polysilicon (LTPS) in the semiconductor layer (hereinafter also referred to as an LTPS transistor). LTPS transistors have high field-effect mobility and good frequency characteristics.

[0225] By using silicon transistors, such as LTPS transistors, circuits that need to be driven at high frequencies (such as source driver circuits) can be built on the same substrate as the display unit, simplifying the external circuits mounted on the display device and reducing component and mounting costs.

[0226] At least one of the transistors included in the pixel circuit preferably includes a transistor (hereinafter also referred to as an OS transistor) having a metal oxide (hereinafter also referred to as an oxide semiconductor) in a semiconductor layer where a channel is formed. The OS transistor has significantly higher field-effect mobility than a transistor using amorphous silicon. Furthermore, the OS transistor has a significantly smaller source-drain leakage current in an off state (hereinafter also referred to as an off-state current), and can hold charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of an OS transistor can reduce the power consumption of a display device.

[0227] A display device with low power consumption and high driving capability can be realized by using an LTPS transistor for some of the transistors included in a pixel circuit and an OS transistor for the other. In a more preferred example, an OS transistor is used as a transistor that functions as a switch for controlling conduction / non-conduction between wirings, and an LTPS transistor is used as a transistor that controls current.

[0228] For example, one of the transistors provided in the pixel circuit functions as a transistor for controlling a current flowing through a light-emitting device and can be called a driving transistor. One of the source and drain of the driving transistor is electrically connected to a pixel electrode of the light-emitting device. It is preferable to use an LTPS transistor as the driving transistor. This allows the current flowing through the light-emitting device in the pixel circuit to be increased.

[0229] On the other hand, another transistor provided in the pixel circuit functions as a switch for controlling pixel selection / non-selection and can also be called a selection transistor. The gate of the selection transistor is electrically connected to a gate line, and one of the source and drain is electrically connected to a source line (signal line). It is preferable to use an OS transistor as the selection transistor. This allows the gradation of a pixel to be maintained even when the frame frequency is significantly reduced (for example, 1 fps or less), and therefore power consumption can be reduced by stopping the driver circuit when displaying a still image.

[0230] A more specific configuration example will be described below with reference to the drawings.

[0231] 18A shows a block diagram of a display device 610. The display device 610 includes a display portion 611, a driver circuit portion 612, and a driver circuit portion 613.

[0232] The display unit 611 has a plurality of pixels 630 arranged in a matrix. Each pixel 630 has sub-pixels 621R, 621G, and 621B. Each of the sub-pixels 621R, 621G, and 621B has a light-emitting device that functions as a display device.

[0233] The pixel 630 is electrically connected to a wiring GL, a wiring SLR, a wiring SLG, and a wiring SLB. The wirings SLR, SLG, and SLB are each electrically connected to a driver circuit unit 612. The wiring GL is electrically connected to a driver circuit unit 613. The driver circuit unit 612 functions as a source line driver circuit (also referred to as a source driver), and the driver circuit unit 613 functions as a gate line driver circuit (also referred to as a gate driver). The wiring GL functions as a gate line, and the wirings SLR, SLG, and SLB function as source lines.

[0234] The sub-pixel 621R has a light-emitting device that emits red light. The sub-pixel 621G has a light-emitting device that emits green light. The sub-pixel 621B has a light-emitting device that emits blue light. This allows the display device 610 to achieve full-color display. Note that the pixel 630 may also have sub-pixels that have light-emitting devices that emit light of other colors. For example, the pixel 630 may have, in addition to the above three sub-pixels, a sub-pixel that has a light-emitting device that emits white light or a sub-pixel that has a light-emitting device that emits yellow light.

[0235] The wiring GL is electrically connected to the sub-pixels 621R, 621G, and 621B arranged in the row direction (extension direction of the wiring GL). The wiring SLR, wiring SLG, and wiring SLB are electrically connected to the sub-pixels 621R, 621G, and 621B (not shown) arranged in the column direction (extension direction of the wiring SLR), respectively.

[0236] 18B shows an example of a circuit diagram of a pixel 621 that can be applied to the subpixels 621R, 621G, and 621B. The pixel 621 includes a transistor M1, a transistor M2, a transistor M3, a capacitor C1, and a light-emitting device LED. A wiring GL and a wiring SL are electrically connected to the pixel 621. The wiring SL corresponds to any one of the wirings SLR, SLG, and SLB shown in FIG. 18A.

[0237] The transistor M1 has a gate electrically connected to a wiring GL, one of a source and a drain electrically connected to a wiring SL, and the other electrically connected to one electrode of the capacitor C1 and the gate of the transistor M2. The transistor M2 has one of a source and a drain electrically connected to a wiring AL, and the other of a source and a drain electrically connected to one electrode of the light-emitting device LED, the other electrode of the capacitor C1, and one of a source and a drain of the transistor M3. The transistor M3 has a gate electrically connected to a wiring GL, and the other of a source and a drain electrically connected to a wiring RL. The light-emitting device LED has the other electrode electrically connected to a wiring CL.

[0238] The wiring SL is supplied with a data potential D. The wiring GL is supplied with a selection signal. The selection signal includes a potential that turns on a transistor and a potential that turns off a transistor.

[0239] A reset potential is applied to the wiring RL. An anode potential is applied to the wiring AL. A cathode potential is applied to the wiring CL. In the pixel 621, the anode potential is higher than the cathode potential. The reset potential applied to the wiring RL can be a potential such that the potential difference between the reset potential and the cathode potential is smaller than the threshold voltage of the light-emitting device LED. The reset potential can be a potential higher than the cathode potential, the same as the cathode potential, or a potential lower than the cathode potential.

[0240] The transistors M1 and M3 function as switches. The transistor M2 functions as a transistor for controlling the current flowing through the light-emitting device LED. For example, it can be said that the transistor M1 functions as a selection transistor and the transistor M2 functions as a drive transistor.

[0241] Here, it is preferable that all of the transistors M1 to M3 be LTPS transistors. Alternatively, it is preferable that the transistors M1 and M3 be OS transistors and the transistor M2 be an LTPS transistor.

[0242] Alternatively, OS transistors may be used for all of the transistors M1 to M3. In this case, an LTPS transistor may be used for one or more of the transistors included in the driver circuit portion 612 and the driver circuit portion 613, and OS transistors may be used for the remaining transistors. For example, an OS transistor may be used for the transistor provided in the display portion 611, and an LTPS transistor may be used for the transistors provided in the driver circuit portion 612 and the driver circuit portion 613.

[0243] As the OS transistor, a transistor including an oxide semiconductor for a semiconductor layer in which a channel is formed can be used. The semiconductor layer preferably contains, for example, indium, M (M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin. In particular, an oxide containing indium, gallium, and zinc (also referred to as IGZO) is preferably used for the semiconductor layer of the OS transistor. Alternatively, an oxide containing indium, tin, and zinc is preferably used. Alternatively, an oxide containing indium, gallium, tin, and zinc is preferably used.

[0244] A transistor using an oxide semiconductor, which has a wider band gap and a lower carrier density than silicon, can achieve an extremely small off-state current. Therefore, the small off-state current allows charge stored in a capacitor connected in series with the transistor to be held for a long period of time. Therefore, it is preferable to use transistors including an oxide semiconductor for each of the transistors M1 and M3 connected in series with the capacitor C1. Using transistors including an oxide semiconductor as the transistors M1 and M3 can prevent charge held in the capacitor C1 from leaking through the transistor M1 or M3. Furthermore, because charge held in the capacitor C1 can be held for a long period of time, a still image can be displayed for a long period of time without rewriting data in the pixel 621.

[0245] Note that although the transistors are shown as n-channel transistors in FIG. 18B, p-channel transistors can also be used.

[0246] In addition, the transistors included in the pixel 621 are preferably formed side by side on the same substrate.

[0247] As the transistor included in the pixel 621, a transistor having a pair of gates overlapping with each other with a semiconductor layer interposed therebetween can be used.

[0248] In a transistor having a pair of gates, when the pair of gates are electrically connected to each other and supplied with the same potential, the on-state current of the transistor is increased and the saturation characteristics are improved. A potential for controlling the threshold voltage of the transistor may be supplied to one of the pair of gates. Supplying a constant potential to one of the pair of gates can improve the stability of the electrical characteristics of the transistor. For example, one gate of the transistor may be electrically connected to a wiring to which a constant potential is supplied, or to its own source or drain.

[0249] 18C is an example in which the transistors M1 and M3 each have a pair of gates. The pair of gates of the transistors M1 and M3 are electrically connected. With this configuration, the period for writing data to the pixel 621 can be shortened.

[0250] 18D is an example in which a transistor having a pair of gates is used for the transistor M2 in addition to the transistors M1 and M3. The pair of gates of the transistor M2 are electrically connected. By using such a transistor for the transistor M2, the saturation characteristics are improved, making it easier to control the light emission brightness of the light-emitting device LED, and thus improving the display quality.

[0251] [Example of Transistor Structure] Hereinafter, an example of a cross-sectional structure of a transistor that can be applied to the display device will be described.

[0252] Configuration Example 1 FIG. 19A is a cross-sectional view including a transistor 410. FIG.

[0253] The transistor 410 is provided over the substrate 401 and has polycrystalline silicon applied to a semiconductor layer. For example, the transistor 410 corresponds to the transistor M2 of the pixel 621. That is, Fig. 19A illustrates an example in which one of the source and the drain of the transistor 410 is electrically connected to the conductive layer 431 of the light-emitting device.

[0254] The transistor 410 includes a semiconductor layer 411, an insulating layer 412, and a conductive layer 413. The semiconductor layer 411 includes a channel formation region 411i and a low-resistance region 411n. The semiconductor layer 411 includes silicon. The semiconductor layer 411 preferably includes polycrystalline silicon. A part of the insulating layer 412 functions as a gate insulating layer. A part of the conductive layer 413 functions as a gate electrode.

[0255] Note that the semiconductor layer 411 can also include a metal oxide (also referred to as an oxide semiconductor) that exhibits semiconductor characteristics. In this case, the transistor 410 can be called an OS transistor.

[0256] The low-resistance region 411n is a region containing an impurity element. For example, when the transistor 410 is an n-channel transistor, phosphorus or arsenic may be added to the low-resistance region 411n. On the other hand, when the transistor 410 is a p-channel transistor, boron or aluminum may be added to the low-resistance region 411n. Furthermore, in order to control the threshold voltage of the transistor 410, the above-mentioned impurities may be added to the channel formation region 411i.

[0257] An insulating layer 421 is provided over a substrate 401. A semiconductor layer 411 is provided over the insulating layer 421. An insulating layer 412 is provided to cover the semiconductor layer 411 and the insulating layer 421. A conductive layer 413 is provided over the insulating layer 412 so as to overlap with the semiconductor layer 411.

[0258] An insulating layer 422 is provided to cover the conductive layer 413 and the insulating layer 412. A conductive layer 414a and a conductive layer 414b are provided over the insulating layer 422. The conductive layer 414a and the conductive layer 414b are electrically connected to the low-resistance region 411n through openings provided in the insulating layer 422 and the insulating layer 412. A part of the conductive layer 414a functions as one of the source electrode and the drain electrode, and a part of the conductive layer 414b functions as the other of the source electrode and the drain electrode. An insulating layer 423 is provided to cover the conductive layer 414a, the conductive layer 414b, and the insulating layer 422.

[0259] A conductive layer 431 functioning as a pixel electrode is provided over the insulating layer 423. The conductive layer 431 is provided over the insulating layer 423 and is electrically connected to the conductive layer 414b in an opening provided in the insulating layer 423. Although not shown here, a terminal of an LED can be mounted on the conductive layer 431.

[0260] 19B shows a transistor 410a having a pair of gate electrodes, which is different from the transistor 410a shown in FIG. 19A in that a conductive layer 415 and an insulating layer 416 are included.

[0261] The conductive layer 415 is provided over the insulating layer 421. An insulating layer 416 is provided to cover the conductive layer 415 and the insulating layer 421. The semiconductor layer 411 is provided so that at least a channel formation region 411i overlaps with the conductive layer 415 with the insulating layer 416 interposed therebetween.

[0262] 19B , part of the conductive layer 413 functions as a first gate electrode, part of the conductive layer 415 functions as a second gate electrode, part of the insulating layer 412 functions as a first gate insulating layer, and part of the insulating layer 416 functions as a second gate insulating layer.

[0263] Here, when the first gate electrode and the second gate electrode are electrically connected, the conductive layer 413 and the conductive layer 415 may be electrically connected through openings provided in the insulating layers 412 and 416 in a region not shown. When the second gate electrode and the source or drain are electrically connected, the conductive layer 414a or the conductive layer 414b may be electrically connected to the conductive layer 415 through openings provided in the insulating layers 422, 412, and 416 in a region not shown.

[0264] 19A or 19B can be used as all the transistors constituting the pixel 621. In this case, the transistor 410a may be used as all the transistors constituting the pixel 621, the transistor 410 may be used as all the transistors constituting the pixel 621, or the transistor 410 may be used as all the transistors constituting the pixel 621. Alternatively, the transistor 410a and the transistor 410 may be used in combination.

[0265] [Structure Example 3] Hereinafter, a structure example including both a transistor in which silicon is used for a semiconductor layer and a transistor in which a metal oxide is used for a semiconductor layer will be described.

[0266] FIG. 19C shows a cross-sectional schematic diagram including transistor 410a and transistor 450.

[0267] The transistor 410a can be configured as in the above-described Structure Example 1. Note that although the example using the transistor 410a is shown here, a structure including the transistor 410 and the transistor 450 may be used, or a structure including all of the transistor 410, the transistor 410a, and the transistor 450 may be used.

[0268] The transistor 450 is a transistor in which a metal oxide is used for a semiconductor layer. In the configuration shown in Figure 19C, for example, the transistor 450 corresponds to the transistor M1 of the pixel 621, and the transistor 410a corresponds to the transistor M2. That is, Figure 19C shows an example in which one of the source and the drain of the transistor 410a is electrically connected to the conductive layer 431.

[0269] FIG. 19C shows an example in which the transistor 450 has a pair of gates.

[0270] The transistor 450 includes a conductive layer 455, an insulating layer 422, a semiconductor layer 451, an insulating layer 452, and a conductive layer 453. Part of the conductive layer 453 functions as a first gate of the transistor 450, and part of the conductive layer 455 functions as a second gate of the transistor 450. In this case, part of the insulating layer 452 functions as a first gate insulating layer of the transistor 450, and part of the insulating layer 422 functions as a second gate insulating layer of the transistor 450.

[0271] The conductive layer 455 is provided over the insulating layer 412. The insulating layer 422 is provided to cover the conductive layer 455. The semiconductor layer 451 is provided over the insulating layer 422. The insulating layer 452 is provided to cover the semiconductor layer 451 and the insulating layer 422. The conductive layer 453 is provided over the insulating layer 452 and has a region overlapping with the semiconductor layer 451 and the conductive layer 455.

[0272] An insulating layer 426 is provided to cover the insulating layer 452 and the conductive layer 453. A conductive layer 454a and a conductive layer 454b are provided over the insulating layer 426. The conductive layer 454a and the conductive layer 454b are electrically connected to the semiconductor layer 451 through openings provided in the insulating layer 426 and the insulating layer 452. A part of the conductive layer 454a functions as one of the source electrode and the drain electrode, and a part of the conductive layer 454b functions as the other of the source electrode and the drain electrode. An insulating layer 423 is provided to cover the conductive layer 454a, the conductive layer 454b, and the insulating layer 426.

[0273] Here, the conductive layers 414a and 414b electrically connected to the transistor 410a are preferably formed by processing the same conductive film as the conductive layers 454a and 454b. Figure 19C shows a configuration in which the conductive layers 414a, 414b, 454a, and 454b are formed on the same surface (i.e., in contact with the top surface of the insulating layer 426) and contain the same metal element. In this case, the conductive layers 414a and 414b are electrically connected to the low-resistance region 411n through openings provided in the insulating layer 426, the insulating layer 452, the insulating layer 422, and the insulating layer 412. This is preferable because it simplifies the manufacturing process.

[0274] The conductive layer 413 functioning as the first gate electrode of the transistor 410a and the conductive layer 455 functioning as the second gate electrode of the transistor 450 are preferably formed by processing the same conductive film. In Figure 19C, the conductive layer 413 and the conductive layer 455 are formed on the same surface (i.e., in contact with the top surface of the insulating layer 412) and contain the same metal element. This is preferable because it simplifies the manufacturing process.

[0275] In FIG. 19C , the insulating layer 452 functioning as the first gate insulating layer of the transistor 450 covers the end portion of the semiconductor layer 451; however, as in the transistor 450a shown in FIG. 19D , the insulating layer 452 may be processed so that the top surface shape thereof matches or substantially matches the top surface shape of the conductive layer 453.

[0276] In this specification, "top surface shapes that are approximately the same" means that at least a portion of the contours of stacked layers overlap. For example, this includes cases where the upper and lower layers are processed using the same mask pattern or a portion of the same mask pattern. However, strictly speaking, the contours may not overlap, and the upper layer may be located inside the lower layer, or outside the lower layer. In these cases, the term "top surface shapes that are approximately the same" is also used.

[0277] Although the transistor 410a corresponds to the transistor M2 and is electrically connected to the pixel electrode in this example, the present invention is not limited to this. For example, the transistor 450 or the transistor 450a may correspond to the transistor M2. In this case, the transistor 410a corresponds to the transistor M1, the transistor M3, or another transistor.

[0278] This embodiment mode can be combined with other embodiment modes as appropriate.

[0279] Seventh Embodiment This embodiment relates to a display device in which sub-pixels are arranged in a matrix, and a light-emitting element (light-emitting diode chip) is provided for each sub-pixel.

[0280] A display device according to one embodiment of the present invention has a configuration in which light-emitting diode chips are mounted separately between subpixels of different colors. Here, in the display device according to one embodiment of the present invention, multiple subpixels emitting light of the same color are arranged adjacently not only in the column direction but also in the row direction. In other words, the display device has a structure in which multiple subpixels emitting light of the same color are independently divided.

[0281] In this specification, two subpixels that have the same coordinate representing their row positions but differ by one in coordinate representing their column positions are referred to as subpixels adjacent in the row direction. For example, the subpixel in the first row and second column is adjacent in the row direction to the subpixel in the first row and first column. Furthermore, two subpixels that have the same coordinate representing their column positions but differ by one in coordinate representing their row positions are referred to as subpixels adjacent in the column direction. For example, the subpixel in the second row and first column is adjacent in the column direction to the subpixel in the first row and first column. Similar expressions can be used for elements other than subpixels that are arranged in a matrix. For example, when dividing multiple subpixels that emit light of the same color into four, the row direction can be divided into two and the column direction can be divided into two.

[0282] [Structure Example of Display Device] FIG. 20 is a top view illustrating a structure example of a pixel 103 of a display device that is one embodiment of the present invention.

[0283] The pixel 103 shown in FIG. 20 is composed of four subpixels: subpixel 110a, subpixel 110b, subpixel 110c, and subpixel 110d. The subpixels 110a, 110b, 110c, and 110d each have a light-emitting element that emits light of a different color. The subpixels 110a, 110b, and 110c may be subpixels of four colors: red (R), green (G), blue (B), and white (W). The subpixel 110a shown in FIG. 20 may correspond to one LED chip, and an LED chip having two terminals may be mounted. Furthermore, to reduce the mounting effort, multiple subpixels may be mounted on a single chip. For example, a single chip may have three subpixels of red (R), green (G), and blue (B), and an LED chip with four terminals may be mounted. 20 shows an example in which one chip is configured with sub-pixels of four colors, each surrounded by a square, and arranged in a matrix. When configured with sub-pixels of four colors, there are five terminals. Also, in FIG. 20, the areas of the sub-pixels are the same, but this is not particularly limited. For example, when sub-pixels of three colors are used, only the green sub-pixel may have a larger area.

[0284] In this specification, matters common to, for example, the subpixels 110a, 110b, 110c, and 110d may be described. When describing matters common to other components distinguished by alphabets, the other components may be described using symbols without the alphabets.

[0285] FIG. 20 shows the sub-pixels in the first row and first column to the sixth row and sixth column.

[0286] In this specification, the row direction is referred to as the X direction, and the column direction is referred to as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly.

[0287] This embodiment mode can be freely combined with other embodiment modes.

[0288] Embodiment 8 In this embodiment, an example of a display device according to one embodiment of the present invention will be described.

[0289] In the display device of this embodiment, a pixel may be configured to have multiple types of subpixels having light-emitting devices that emit different colors. For example, a pixel may be configured to have three types of subpixels. The three subpixels may include subpixels of three colors: red (R), green (G), and blue (B), or subpixels of three colors: yellow (Y), cyan (C), and magenta (M). Alternatively, a pixel may be configured to have four types of subpixels. The four subpixels may include subpixels of four colors: R, G, B, and white (W), or subpixels of four colors: R, G, B, and Y.

[0290] The arrangement of the sub-pixels is not particularly limited, and various methods can be applied, such as a stripe arrangement, an S-stripe arrangement, a matrix arrangement, a delta arrangement, a Bayer arrangement, and a pentile arrangement.

[0291] Examples of the top surface shape of the sub-pixel include a triangle, a quadrangle (including a rectangle and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, and a circle. The top surface shape of the sub-pixel here corresponds to the top surface shape of the light-emitting region of the light-emitting device.

[0292] In a display device having a light-emitting device and a light-receiving device in each pixel, the pixel has a light-receiving function, so that it is possible to detect contact or proximity of an object while displaying an image. For example, in addition to displaying an image using all of the sub-pixels of the display device, some of the sub-pixels can emit light as a light source and the remaining sub-pixels can display an image.

[0293] The pixel shown in FIGS. 21A, 21B, and 21C includes subpixels G, B, R, and PS.

[0294] A stripe arrangement is applied to the pixels shown in Fig. 21A, and a matrix arrangement is applied to the pixels shown in Fig. 21B.

[0295] The pixel array shown in FIG. 21C has a configuration in which three subpixels (subpixel R, subpixel G, and subpixel PS) are vertically aligned next to one subpixel (subpixel B).

[0296] The pixel shown in FIG. 21D has subpixels G, B, R, IR, and PS.

[0297] 21D shows an example in which one pixel is provided across two rows, with the upper row (first row) having three subpixels (subpixels G, B, and R), and the lower row (second row) having two subpixels (one subpixel PS and one subpixel IR).

[0298] The layout of the sub-pixels is not limited to the configurations shown in FIGS. 21A to 21D.

[0299] Subpixel R has a light-emitting device that emits red light. Subpixel G has a light-emitting device that emits green light. Subpixel B has a light-emitting device that emits blue light. Subpixel IR has a light-emitting device that emits infrared light. Subpixel PS has a light-receiving device. There are no particular limitations on the wavelength of light detected by subpixel PS, but it is preferable that the light-receiving device of subpixel PS is sensitive to light emitted by the light-emitting device of subpixel R, subpixel G, subpixel B, or subpixel IR. For example, it is preferable to detect one or more of light in the blue, purple, blue-purple, green, yellow-green, yellow, orange, and red wavelength regions, and light in the infrared wavelength region.

[0300] The light-receiving area of ​​the subpixel PS is smaller than the light-emitting area of ​​the other subpixels. The smaller the light-receiving area, the narrower the imaging range, which makes it possible to suppress blurring in the imaging result and improve resolution. Therefore, by using the subpixel PS, high-definition or high-resolution imaging can be performed. For example, the subpixel PS can be used to capture images for personal authentication using fingerprints, palm prints, irises, pulse shapes (including vein shapes and arterial shapes), or faces.

[0301] The subpixel PS can be used in a touch sensor (also called a direct touch sensor) or a near-touch sensor (also called a hover sensor, hover touch sensor, non-contact sensor, or touchless sensor). For example, the subpixel PS preferably detects infrared light, which enables touch detection even in dark places.

[0302] Here, the touch sensor or near-touch sensor can detect the proximity or contact of an object (finger, hand, or pen). The touch sensor can detect an object when the display device and the object are in direct contact with each other. The near-touch sensor can detect an object even if the object does not touch the display device. For example, it is preferable that the display device be configured to detect the object when the distance between the display device and the object is in the range of 0.1 mm to 300 mm, preferably 3 mm to 50 mm. This configuration makes it possible to operate the display device without the object directly touching it, in other words, to operate the display device in a non-contact (touchless) manner. This configuration reduces the risk of the display device becoming dirty or scratched, or makes it possible to operate the display device without the object directly touching dirt (e.g., dust or viruses) attached to the display device.

[0303] The non-contact sensor function can also be called a hover sensor function, a hover-touch sensor function, a near-touch sensor function, or a touchless sensor function. The touch sensor function can also be called a direct-touch sensor function.

[0304] Furthermore, the display device of one embodiment of the present invention can have a variable refresh rate. For example, the refresh rate can be adjusted (for example, within a range of 0.01 Hz to 240 Hz) depending on the content displayed on the display device, thereby reducing power consumption. Furthermore, driving that reduces the power consumption of the display device by driving it at a reduced refresh rate may be called idling stop (IDS) driving.

[0305] The drive frequency of the touch sensor or near-touch sensor may be changed depending on the refresh rate. For example, if the refresh rate of the display device is 120 Hz, the drive frequency of the touch sensor or near-touch sensor may be set to a frequency higher than 120 Hz (typically 240 Hz). This configuration enables low power consumption and an increased response speed of the touch sensor or near-touch sensor.

[0306] In order to capture high-resolution images, it is preferable that the sub-pixels PS be provided in all pixels of the display device. On the other hand, when used in a touch sensor or near-touch sensor, the sub-pixels PS do not require as high accuracy as when capturing an image of a fingerprint, so they may be provided in only some of the pixels of the display device. By making the number of sub-pixels PS in the display device smaller than the number of sub-pixels R, the detection speed can be increased.

[0307] FIG. 21E shows an example of a pixel circuit of a sub-pixel having a light-receiving device, and FIG. 21F shows an example of a pixel circuit of a sub-pixel having a light-emitting device.

[0308] 21E includes a light receiving device PD, a transistor M11, a transistor M12, a transistor M13, a transistor M14, and a capacitance element C2. Here, an example is shown in which a photodiode is used as the light receiving device PD.

[0309] The light-receiving device PD has an anode electrically connected to the wiring V1 and a cathode electrically connected to one of the source and drain of the transistor M11. The transistor M11 has a gate electrically connected to the wiring TX and the other of the source and drain electrically connected to one electrode of the capacitor C2, one of the source and drain of the transistor M12, and the gate of the transistor M13. The transistor M12 has a gate electrically connected to the wiring RES and the other of the source and drain electrically connected to the wiring V2. The transistor M13 has one of the source and drain electrically connected to the wiring V3 and the other of the source and drain electrically connected to one of the source and drain of the transistor M14. The transistor M14 has a gate electrically connected to the wiring SE and the other of the source and drain electrically connected to the wiring OUT1.

[0310] A constant potential is supplied to the wiring V1, the wiring V2, and the wiring V3. When the light-receiving device PD is driven with a reverse bias, a potential higher than the potential of the wiring V1 is supplied to the wiring V2. The transistor M12 is controlled by a signal supplied to the wiring RES and has a function of resetting the potential of a node connected to the gate of the transistor M13 to the potential supplied to the wiring V2. The transistor M11 is controlled by a signal supplied to the wiring TX and has a function of controlling the timing at which the potential of the node changes depending on the current flowing through the light-receiving device PD. The transistor M13 functions as an amplifying transistor that outputs according to the potential of the node. The transistor M14 is controlled by a signal supplied to the wiring SE and functions as a selection transistor that reads out an output according to the potential of the node to an external circuit connected to the wiring OUT1.

[0311] 21F includes a light-emitting device LED, transistors M15, M16, and M17, and a capacitor C3. Here, a light-emitting diode is used as the light-emitting device LED. It is particularly preferable to use a red, blue, or green LED as the light-emitting device LED.

[0312] The transistor M15 has a gate electrically connected to a wiring VG, one of its source and drain electrically connected to a wiring VS, and the other of its source and drain electrically connected to one electrode of the capacitor C3 and the gate of the transistor M16. One of the source and drain of the transistor M16 is electrically connected to a wiring V4, and the other is electrically connected to the anode of the light-emitting device LED and one of the source and drain of the transistor M17. The transistor M17 has a gate electrically connected to a wiring MS, and the other of its source and drain electrically connected to a wiring OUT2. The cathode of the light-emitting device LED is electrically connected to a wiring V5.

[0313] A constant potential is supplied to the wiring V4 and the wiring V5. The anode side of the light-emitting device LED can be set to a high potential, and the cathode side can be set to a lower potential than the anode side. The transistor M15 is controlled by a signal supplied to the wiring VG and functions as a selection transistor for controlling the selection state of the pixel circuit PIX2. The transistor M16 also functions as a drive transistor that controls the current flowing through the light-emitting device LED according to the potential supplied to its gate. When the transistor M15 is in a conductive state, the potential supplied to the wiring VS is supplied to the gate of the transistor M16, and the light emission brightness of the light-emitting device LED can be controlled according to that potential. The transistor M17 is controlled by a signal supplied to the wiring MS and has the function of outputting the potential between the transistor M16 and the light-emitting device LED to the outside via the wiring OUT2.

[0314] Here, it is preferable to use transistors that use a metal oxide (oxide semiconductor) in a semiconductor layer in which a channel is formed for the transistors M11, M12, M13, and M14 included in the pixel circuit PIX1, and the transistors M15, M16, and M17 included in the pixel circuit PIX2.

[0315] A transistor using a metal oxide, which has a wider band gap and a lower carrier density than silicon, can achieve an extremely small off-state current. Therefore, the small off-state current allows charge stored in a capacitor connected in series to the transistor to be held for a long period of time. Therefore, it is preferable to use a transistor including an oxide semiconductor for the transistor M11, the transistor M12, and the transistor M15, which are connected in series to the capacitor C2 or the capacitor C3. Furthermore, by using a transistor including an oxide semiconductor for other transistors as well, manufacturing costs can be reduced. However, one embodiment of the present invention is not limited thereto. A transistor using silicon for a semiconductor layer (hereinafter also referred to as a Si transistor) may also be used.

[0316] Note that the off-state current of an OS transistor per 1 μm of channel width at room temperature is 1 aA (1×10 −１８ A) Below, 1zA (1×10 −２１ A) or less, or 1yA (1 x 10 −２４ Note that the off-state current of a Si transistor per 1 μm of channel width at room temperature can be 1 fA (1×10 −１５ A) More than 1pA (1×10 −１２ Therefore, it can be said that the off-state current of an OS transistor is about 10 orders of magnitude lower than that of a Si transistor.

[0317] Furthermore, when a transistor operates in the saturation region, an OS transistor can reduce the change in source-drain current caused by a change in gate-source voltage compared to a Si transistor. Therefore, by using an OS transistor as a driving transistor included in a pixel circuit, the current flowing between the source and drain can be precisely determined by changing the gate-source voltage, thereby enabling precise control of the amount of current flowing through the light-emitting device. This allows precise control of the light emission luminance of the light-emitting device (enhancing the gradation in the pixel circuit).

[0318] Furthermore, in terms of the saturation characteristics of the current that flows when a transistor operates in the saturation region, an OS transistor can flow a constant current (saturation current) that is more stable than a Si transistor, even when the source-drain voltage gradually increases. Therefore, by using an OS transistor as a driving transistor, a stable constant current can be flowed through a light-emitting device, for example, even when the current-voltage characteristics of an LED light-emitting device vary. In other words, when an OS transistor operates in the saturation region, the source-drain current of the OS transistor remains almost unchanged even when the source-drain voltage increases, thereby stabilizing the light-emitting luminance of the light-emitting device.

[0319] As described above, by using an OS transistor as a driving transistor included in a pixel circuit, it is possible to achieve "suppression of floating black," "increase in light emission luminance," "multiple gray levels," and "suppression of variations in light-emitting devices." Therefore, a display device including the pixel circuit can display clear and smooth images, resulting in one or more of image clarity, image sharpness, and a high contrast ratio. Furthermore, by configuring the driving transistor included in the pixel circuit to have an extremely low off-state current, black display in the display device can be achieved with extremely little light leakage (true black display).

[0320] Alternatively, the transistors M11 to M17 may be transistors in which silicon is used for a semiconductor layer in which a channel is formed. In particular, using silicon with high crystallinity, such as single crystal silicon or polycrystalline silicon, is preferable because high field-effect mobility can be achieved and higher-speed operation can be achieved.

[0321] Alternatively, one or more of the transistors M11 to M17 may be a transistor including an oxide semiconductor (OS transistor), and the remaining transistors may be silicon transistors (Si transistors). Note that the Si transistors may be low-temperature polysilicon (LTPS) transistors (hereinafter referred to as LTPS transistors). A combination of an OS transistor and an LTPS transistor may be referred to as LTPO. The LTPO configuration allows the use of an LTPS transistor with high mobility and an OS transistor with low off-state current, thereby providing a display panel with high display quality.

[0322] Note that although the transistors are depicted as n-channel transistors in FIGS. 21E and 21F, p-channel transistors can also be used.

[0323] The transistors of the pixel circuit PIX1 and the transistors of the pixel circuit PIX2 are preferably formed side by side on the same substrate. In particular, it is preferable that the transistors of the pixel circuit PIX1 and the transistors of the pixel circuit PIX2 are mixed and periodically arranged in one region.

[0324] It is also preferable to provide one or more layers including one or both of a transistor and a capacitor at a position overlapping the light receiving device PD or the light emitting device LED, thereby reducing the effective area occupied by each pixel circuit and realizing a high-definition light receiving section or display section.

[0325] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0326] Embodiment 9 In this embodiment, electronic devices using a display device of one embodiment of the present invention will be described with reference to FIGS.

[0327] In this embodiment mode, an example in which the display device described in any one of Embodiment Modes 1 to 4 is installed inside a vehicle will be described.

[0328] Fig. 22 is a diagram illustrating an example of the configuration of a vehicle. Fig. 22 shows a dashboard 151 arranged around the driver's seat, a display device 154 fixed in front of the driver's seat, a camera 155, an air outlet 156, a door 158a on the right side of the driver's seat, and a door 158b on the left side of the driver's seat. The display device 154 is provided across the area in front of the driver's seat.

[0329] The display device 154 fixed in front of the driver's seat can be any one of the display devices described in Embodiments 1 to 4. Fig. 22 illustrates the display device 154 as a single display surface, and shows an example in which the display device 154 is configured by combining a total of 18 light-emitting devices in two rows and nine columns. Although the boundaries of pixel regions are indicated by dotted lines in Fig. 22 , the dotted lines are not displayed in the actual display image, and the display device 154 has no seams or is inconspicuous. The display device 154 may also have a see-through structure in which a translucent region is provided to allow the outside to be seen.

[0330] The display device 154 is preferably provided with a touch sensor or a non-contact proximity sensor, or is preferably capable of gesture operation using a separately provided camera.

[0331] Figure 22 shows an autonomous vehicle that does not have a handle (also called a steering wheel), but this is not limited to this, and a handle may be provided, and a display device with a curved surface may be provided on the handle, in which case the configuration shown in embodiment 2 can be used.

[0332] Furthermore, multiple cameras 155 for capturing images of the rear and lateral conditions may be installed outside the vehicle. While FIG. 22 shows an example in which the cameras 155 are installed instead of the side mirrors, both side mirrors and cameras may be installed. A CCD camera or a CMOS camera may be used as the camera 155. Furthermore, an infrared camera may be used in combination with these cameras. The infrared camera's output level increases as the temperature of the subject increases, making it possible to detect or extract living organisms (people or animals).

[0333] The image captured by the camera 155 can be output to the display device 154. This display device 154 is mainly used to assist driving of the vehicle. By capturing images of the rear and lateral conditions with a wide angle of view by the camera 155 and displaying the images on the display device 154, the driver can see blind spots, thereby preventing accidents from occurring.

[0334] Alternatively, a range image sensor may be provided on the roof of the vehicle, and an image obtained by the range image sensor may be displayed on the display device 154. As the range image sensor, an image sensor or a LIDAR (Light Detection and Ranging) may be used. By displaying the image obtained by the image sensor and the image obtained by the range image sensor on the display device 154, more information can be provided to the driver, and driving assistance can be provided.

[0335] Furthermore, the display device 152 having a curved surface can be provided inside the roof of the vehicle, that is, on the ceiling. When the display device 152 having a curved surface is provided on the ceiling, the display device described in Embodiment 1 or 2 can be applied.

[0336] Furthermore, the display devices 152 and 154 may have the function of displaying map information, traffic information, television images, and DVD images.

[0337] The images displayed on the display device 154 can be freely set according to the driver's preferences. For example, a television image, a DVD image, or a web video can be displayed in the left image area, map information can be displayed in the central image area, and measurements such as a speedometer and a tachometer can be displayed in the right image area.

[0338] 22, display devices 159a and 159b are provided along the surfaces of right door 158a and left door 158b, respectively. Each of display devices 159a and 159b can be formed using one or more light-emitting devices. For example, one display surface can be formed using one row and two columns of light-emitting devices.

[0339] The display device 159a and the display device 159b are disposed so as to face each other.

[0340] It is also preferable that at least one of the display devices 152, 154, 159a, and 159b is a display device having an imaging function.

[0341] For example, when the driver touches at least one image area of ​​the display devices 152, 154, 159a, and 159b, the vehicle can perform biometric authentication such as fingerprint authentication or palm print authentication. The vehicle may have a function for adjusting the environment to suit the driver's preferences when the driver is authenticated by biometric authentication. For example, it is preferable to perform one or more of the following after authentication: adjusting the seat position, adjusting the steering wheel position, adjusting the orientation of the camera 155, setting the brightness, setting the air conditioner, setting the wiper speed (frequency), setting the audio volume, and reading the audio playlist.

[0342] Furthermore, if the driver is authenticated by biometric authentication, the car can be automatically put into a state where it can be driven, for example, with the engine running, or in the case of an electric car, it can be started, which is preferable because it eliminates the need for a key, which was previously required.

[0343] Although the display device surrounding the driver's seat has been described here, a display device can also be provided in the rear seat so as to surround the passengers.

[0344] Another example will be described with reference to FIG.

[0345] Fig. 23 is a diagram illustrating an example of the configuration of a vehicle. Fig. 23 shows a dashboard 852, a steering wheel 841, a windshield 854, a camera 855, an air vent 856, a passenger door 858a, and a driver door 858b, which are arranged around the driver's seat and passenger seat. The display unit 851 is provided across the left and right sides of the dashboard 852.

[0346] The steering wheel 841 has a light receiving / emitting unit 840. The light receiving / emitting unit 840 has a function of emitting light and a function of capturing an image. The light receiving / emitting unit 840 can obtain biometric information, such as the driver's fingerprint, palm print, or vein pattern, and the driver can be authenticated based on the biometric information. Therefore, only drivers who have been registered in advance can start the vehicle, thereby realizing a vehicle with an extremely high level of security.

[0347] Furthermore, multiple cameras 855 for capturing images of the rear and lateral conditions may be installed outside the vehicle. While FIG. 23 shows an example in which the camera 855 is installed instead of the side mirror, both a side mirror and a camera may be installed. A CCD camera or a CMOS camera may be used as the camera 855. Furthermore, an infrared camera may be used in combination with these cameras. The output level of an infrared camera increases as the temperature of the subject increases, so that it is possible to detect or extract a living body (person or animal).

[0348] An image captured by the camera 855 can be output to either or both of the display unit 851 and the light-emitting and receiving unit 840. The display unit 851 or the light-emitting and receiving unit 840 is used to mainly assist driving of the vehicle. By capturing an image of the rear-side situation with a wide angle of view using the camera 855 and displaying the image on the display unit 851 or the light-emitting and receiving unit 840, the driver can see blind spots, thereby preventing accidents from occurring.

[0349] The display unit 851 may also have the function of displaying map information, traffic information, television images, and DVD images. For example, the display panels 880a and 880b can be used as a single display screen to display large map information. The number of display panels can be increased depending on the images to be displayed.

[0350] Furthermore, in FIG. 23 , the display unit 851 is provided across the dashboard, center console, and left and right pillars. While FIG. 23 illustrates an example in which the display unit 851 is configured with eight display panels (display panels 880a to 880h), the number of display panels is not limited to this and may be seven or fewer, or nine or more. Display panels 880c and 880d are provided in a position corresponding to the center console. Here, the display panel 880d is shown in combination with a non-rectangular display panel 880c. Although the display panel 880d is rectangular, when the display panel 880d and the display panel 880c are combined into a single panel, the display panels 880d and 880c as a whole form a non-rectangular panel. Display panels 880e and 880f are provided on the far side of the dashboard as viewed from the driver. Display panels 880g and 880h are provided along the pillars. One or more of the display panels 880a to 880h are provided along a curved surface.

[0351] The images displayed on display panels 880a to 880h can be freely set according to the driver's preferences. For example, television images, DVD images, and web videos can be displayed on right-side display panels 880a and 880e, map information can be displayed on central display panel 880c, measurements such as a speedometer and tachometer can be displayed on driver-side display panels 880b and 880f, and audio equipment can be displayed on display panel 880d between the driver's seat and passenger seat. Furthermore, by displaying the external scenery within the driver's line of sight in real time on display panels 880g and 880h provided on the pillars, a pseudo-pillarless vehicle can be realized, and blind spots can be reduced, resulting in a highly safe vehicle.

[0352] 23, a display portion 859a and a display portion 859b are provided along the surface of a passenger-side door 858a and a driver-side door 858b, respectively. The display portion 859a and the display portion 859b can each be formed using one or more display panels.

[0353] Display unit 859a and display unit 859b are arranged to face each other, and display unit 851 is provided on dashboard 852 so as to connect the end of display unit 859a with the end of display unit 859b. This results in the driver and passenger in the front seat being surrounded on the front and both sides by display unit 851, display unit 859a, and display unit 859b. For example, by displaying a continuous image on display unit 859a, display unit 851, and display unit 859b, it is possible to provide the driver or passenger with a highly immersive feeling.

[0354] In addition, a plurality of cameras 855 for capturing images of the rear and lateral situations may be provided outside the vehicle. Although an example in which the cameras 855 are provided instead of the side mirrors is shown in Fig. 23, both the side mirrors and the cameras may be provided.

[0355] A CCD camera or a CMOS camera can be used as the camera 855. Furthermore, an infrared camera may be used in combination with these cameras. The output level of an infrared camera increases as the temperature of the subject increases, so that it is possible to detect or extract a living body (human or animal).

[0356] The image captured by the camera 855 can be output to one or more of the display panels. The camera 855 can mainly assist in driving the vehicle by using the image displayed on this display unit 851. For example, by capturing an image of the rear-side situation with a wide angle of view using the camera 855 and displaying the image on one or more of the display panels, the driver can see the blind spot area, thereby preventing the occurrence of an accident.

[0357] Furthermore, the display units 859a and 859b can display an image that is linked to the view from the vehicle window, which is synthesized from the image acquired by the camera 855. That is, an image that the driver and passengers can see through the doors 858a and 858b can be displayed on the display units 859a and 859b. This allows the driver and passengers to experience the sensation of floating.

[0358] A display panel having an imaging function is preferably used for at least one of the display panels 880a to 880h. A display panel having an imaging function can also be used for at least one of the display panels provided in the display portion 859a and the display portion 859b.

[0359] As described above, the structure of one embodiment of the present invention increases the degree of freedom in designing the display device, and the design of the display device can be improved. In addition, the display device of one embodiment of the present invention can be suitably used when mounted in a vehicle.

[0360] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0361] Embodiment 10 In this embodiment, an electronic device of one embodiment of the present invention will be described with reference to FIGS. 24A and 24B.

[0362] The electronic devices of this embodiment include the display device of one embodiment of the present invention in their display portions. The display device of one embodiment of the present invention can easily achieve high definition and high resolution. Therefore, the display device of one embodiment of the present invention can be used in the display portions of various electronic devices.

[0363] Examples of electronic devices include electronic devices with relatively large screens, such as television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproduction devices.

[0364] In particular, the display device of one embodiment of the present invention can have high resolution and can therefore be suitably used in electronic devices having a relatively small display area. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), head-mounted display devices for VR, glasses-type devices for AR and MR, and head-mounted wearable devices.

[0365] The display device of one embodiment of the present invention preferably has an extremely high resolution such as HD (1280 × 720 pixels), FHD (1920 × 1080 pixels), WQHD (2560 × 1440 pixels), WQXGA (2560 × 1600 pixels), 4K (3840 × 2160 pixels), or 8K (7680 × 4320 pixels). A resolution of 4K, 8K, or higher is particularly preferable. Furthermore, the pixel density (resolution) of the display device of one embodiment of the present invention is preferably 100 ppi or higher, more preferably 300 ppi or higher, more preferably 500 ppi or higher, more preferably 1000 ppi or higher, more preferably 2000 ppi or higher, more preferably 3000 ppi or higher, more preferably 5000 ppi or higher, and even more preferably 7000 ppi or higher. By using a display device having either or both of high resolution and high definition, it is possible to further enhance the sense of realism and depth in electronic devices for portable or personal use in home use. Furthermore, the screen ratio (aspect ratio) of the display device of one embodiment of the present invention is not particularly limited. For example, the display device can support various screen ratios (for example, aspect ratios of 1:1 (square), 4:3, 16:9, and 16:10).

[0366] The electronic device of this embodiment may have a sensor (including a function to measure force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0367] 24A shows an example of a television set. A television set 7100 has a display portion 7000 built into a housing 7101. Here, the housing 7101 is supported by a stand 7103.

[0368] The display device of one embodiment of the present invention can be applied to the display portion 7000. The display surface of the display portion 7000 has a curved surface, and the display device described in any one of Embodiments 1 to 3 can be applied to the display portion 7000.

[0369] 24A can be operated using operation switches provided on the housing 7101 and a separate remote control 7111. Alternatively, a touch sensor may be provided in the display portion 7000, and the television set 7100 may be operated by touching the display portion 7000 with a finger. The remote control 7111 may have a display portion that displays information output from the remote control 7111. Using operation keys or a touch panel provided on the remote control 7111, the channel and volume can be controlled, and an image displayed on the display portion 7000 can be controlled.

[0370] The television device 7100 is configured to include a receiver and a modem. The receiver can receive general television broadcasts. In addition, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers) information communication.

[0371] FIG. 24B shows an example of digital signage.

[0372] 24B shows a digital signage 7400 attached to a cylindrical pillar 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pillar 7401.

[0373] In FIG. 24B, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0374] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it will attract people's attention, which can increase the advertising effectiveness of, for example, advertisements.

[0375] Applying a touch panel to the display unit 7000 is preferable because it not only displays images or videos on the display unit 7000 but also allows the user to intuitively operate it. Furthermore, when used to provide route information or traffic information, the intuitive operation can improve usability.

[0376] 24B , the digital signage 7400 is preferably capable of wirelessly communicating with an information terminal 7411, which is a smartphone carried by a user. For example, advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7411. By operating the information terminal 7411, the display on the display unit 7000 can be switched.

[0377] Furthermore, the digital signage 7400 can be made to run a game using the screen of the information terminal 7411 as an operating means (controller), thereby allowing an unspecified number of users to simultaneously participate in and enjoy the game.

[0378] This embodiment mode can be combined with other embodiment modes as appropriate.

[0379] 10: Support, 11: Support, 12a: Third substrate, 12b: Fourth substrate, 12: Substrate, 13: Cover material, 14b: Light emission direction, 15: Area, 16a: Light emitting panel, 16b: Light emitting panel, 16c: Light emitting panel, 16d: Light emitting panel, 16e: Fifth light emitting panel, 16f: Sixth light emitting panel, 16g: Seventh light emitting panel, 16h: Eighth light emitting panel, 17B: Light emitting element, 17G: Light emitting element, 17R: Light emitting element, 17: Light emitting diode chip, 18a: Nitride film, 18b: Nitride film, 19: Resin, 21: Electrode, 23: Electrode, 51A: LED chip section, 51B: LED chip, 51: LED chip, 71A: substrate, 71: substrate, 75a: n-type contact layer, 75b: n-type cladding layer, 75: n-type semiconductor layer, 77a: barrier layer, 77b: well layer, 77: light-emitting layer, 79a: p-type cladding layer, 79b: p-type contact layer, 79: p-type semiconductor layer, 81: semiconductor layer, 83: electrode, 85: electrode, 87: electrode, 89: insulating layer, 103: pixel, 110a: sub-pixel, 110b: sub-pixel, 110c: sub-pixel, 110d: sub-pixel, 151: dashboard, 152: display device, 154: display device, 155: camera, 156: air outlet, 158a : door, 158b: door, 159a: display device, 159b: display device, 401: substrate, 410a: transistor, 410: transistor, 411i: channel formation region, 411n: low resistance region, 411: semiconductor layer, 412: insulating layer, 413: conductive layer, 414a: conductive layer, 414b: conductive layer, 415: conductive layer, 416: insulating layer, 421: insulating layer, 422: insulating layer, 423: insulating layer, 426: insulating layer, 431: conductive layer, 450a: transistor, 450: transistor, 451: semiconductor layer, 452: insulating layer, 453: conductive layer, 454a: conductive layer, 454b: conductive layer conductive layer, 455: conductive layer, 610: display device, 611: display section, 612: drive circuit section, 613: drive circuit section, 621B: sub-pixel, 621G: sub-pixel, 621R: sub-pixel, 621: pixel, 630: pixel, 700A: display device, 700: laser irradiation line, 702: pixel region, 704: gate driver circuit section, 706: source driver circuit section, 710: signal line, 711: routing wiring section, 732: resin, 736: colored layer, 738: light-shielding layer, 740: second substrate, 742: adhesive layer, 743: resin layer, 744: insulating layer, 745: first substrate, 750: transistor,752: transistor, 770: insulating layer, 772: conductive layer, 774: conductive layer, 782: light-emitting element, 790: capacitor element, 791: bump, 793: bump, 795: resin layer, 797: phosphor layer, 800: flexible substrate, 801: second substrate, 810: flexible substrate, 811: second substrate, 820: element layer, 821: element layer, 840: light-emitting / receiving portion, 841: stearin wheel, 851: display unit, 852: dashboard, 854: windshield, 855: camera, 856: air vent, 858a: door, 858b: door, 859a: display unit, 859b: display unit, 880a: display panel, 880b: display panel, 880c: display panel, 880d: display panel, 880e: display panel, 880f: display panel, 880g: display panel, 880 h: display panel, 900: LED chip substrate, 901: film, 903: plate, 905: table, 907: grindstone, 909: grindstone wheel, 911: scribe line, 913: receiving base, 914: opening, 915: blade, 919: first film, 921: first fixture, 923: sheet, 924: plate, 925: second fixture, 927: second film, 9 29: Extrusion mechanism, 950: Device, 951: Stage, 953: Single-axis robot, 955: Single-axis robot, 957: Camera, 959: Grip mechanism, 961: Control device, 963: Unit, 7000: Display unit, 7100: Television device, 7101: Housing, 7103: Stand, 7111: Remote control device, 7400: Digital signage, 7401: Pillar, 7411: Information terminal device,

Claims

1. A plurality of flexible substrates on which a plurality of micro LED chips are mounted; A substrate having a nitride film provided thereon; a resin provided between the flexible substrate and the substrate having the nitride film; The electronic device wherein light emitted from the micro LED chip passes through a substrate on which the nitride film is provided.

2. In claim 1, The flexible substrate has a light-transmitting property.

3. In claim 1, The electronic device, wherein adjacent flexible substrates among the plurality of flexible substrates overlap each other at their ends.

4. In claim 1, The electronic device, wherein the substrate on which the nitride film is provided is transparent.

5. In claim 1, The electronic device, wherein the resin has light-transmitting properties.

6. In claim 1, The electronic device, wherein the nitride film is a silicon nitride film.