electronic machines

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

[Technical Field]

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

[0002] It should be noted that one aspect of the present invention is not limited to the above-mentioned technical field. Examples of technical fields of one aspect of the present invention disclosed herein include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting devices, input devices, input / output devices, methods for driving them, or methods for manufacturing them.

[0003] In this specification, "semiconductor device" refers to any device that can function by utilizing semiconductor properties. Transistors, semiconductor circuits, computing devices, and memory devices are examples of semiconductor devices. Furthermore, imaging devices, electro-optical devices, power generation devices (including thin-film solar cells and organic thin-film solar cells), and electronic devices may also have semiconductor devices. [Background technology]

[0004] In recent years, the applications of display devices have diversified. For example, they are used in personal digital information terminals, home television equipment (also called televisions or television receivers), digital signage, and PID (Public Information Display). Typical examples of display devices include those equipped with light-emitting elements such as organic EL (Electro-Luminescence) elements and light-emitting diodes (LEDs), those equipped with liquid crystal elements, and electronic paper that displays information using electrophoresis. Furthermore, the brightness required for display devices is increasing year by year to withstand outdoor use.

[0005] An active-matrix type microLED display device has been disclosed that uses a small LED (microLED) as a light-emitting element and a transistor as a switching element connected to each pixel electrode (Patent Documents 1, 2, 3, 4). [Prior Art Document] [Patent Document]

[0006] [Patent Document 1] WO2020 / 065472 [Patent Document 2] WO2019 / 220265 [Patent Document 3] WO2020 / 049392 [Patent Document 4] WO2020 / 049397 [Summary of the Invention] [Problem to be Solved by the Invention]

[0007] In a display device using micro LEDs as display elements, the step of mounting LEDs on a circuit board requires a long time, and reducing manufacturing cost is a challenge. Further, the larger the number of pixels of the display device is, the greater the number of LEDs to be mounted increases, and the longer the time required for mounting becomes. Furthermore, the higher the definition of the display device is, the higher the difficulty of LED mounting becomes.

[0008] In view of the above, one object of one aspect of the present invention is to reduce the manufacturing cost of a display device using micro LEDs as display elements. Alternatively, one object of one aspect of the present invention is to provide a display device using relatively large-area micro LEDs as display elements. Alternatively, one object of one aspect of the present invention is to provide a display device that has a curved display surface and uses relatively large-area micro LEDs as display elements.

[0009] Alternatively, one object of one aspect of the present invention is to manufacture a display device using micro LEDs as display elements with high yield.

[0010] One aspect of the present invention aims to provide a display device with high brightness. Alternatively, one aspect of the present invention aims to provide a display device with high contrast. Alternatively, one aspect of the present invention aims to provide a display device with a fast response speed. Alternatively, one aspect of the present invention aims to provide a display device with low power consumption. Alternatively, one aspect of the present invention aims to provide a display device with low manufacturing costs. Alternatively, one aspect of the present invention aims to provide a display device with a long lifespan. Alternatively, one aspect of the present invention aims to provide a novel display device.

[0011] Furthermore, the description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not need to solve all of these problems. Other problems can be identified from the description in the specification, drawings, and claims. [Means for solving the problem]

[0012] By combining display devices that use multiple micro-LEDs or multiple mini-LEDs as display elements, we will realize a display device for components installed inside a vehicle. Specifically, a display with a curved surface will be installed as an interior feature of the vehicle.

[0013] One aspect of the present invention provides a display device with a curved display surface 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 has the shape of a convex portion or a concave portion.

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

[0015] Furthermore, to improve reliability, the display device, which uses multiple micro-LEDs or multiple mini-LEDs as display elements, is configured to be sandwiched above and below by a cover material (one or two) with a barrier film. A resin is provided between the cover material and the light-emitting element. In addition, by using light-transmitting materials for the cover material and resin, it is possible to configure the device to emit light from the light-emitting element not only in one direction but in two or more directions.

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

[0017] In the above configuration, it is preferable that the flexible substrate, the substrate with the nitride film, or the resin is light-transmitting. It is also preferable that the refractive indices of these materials be approximately the same. The substrate sandwiching the top and bottom for sealing refers to an acrylic resin and can be called a cover material. The nitride film provided on the substrate refers to a silicon nitride film and can also be called a barrier film. It is preferable that the difference in refractive index n between the cover material and the resin is 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 to 750 nm, and refers to the average refractive index for light with wavelengths within the above range. The average refractive index is the value obtained by dividing the sum of the measured refractive indices for each light with wavelengths within the above range by the number of measurement points. The refractive index of air is assumed to be 1.

[0018] While flexible substrates and substrates with a nitride film are generally referred to as "substrates," they may also be called "films" depending on the material and thickness.

[0019] Furthermore, in the above configuration, the display device disclosed herein can be fixed to a support having a curved surface, and at least a portion of the display surface of the display device can be a curved surface. When fixed to a support having a curved surface, it is preferable to use a flexible substrate and a substrate on which a nitride film is provided, both of which are thin in thickness.

[0020] Furthermore, in order to increase the surface area, a display device with a single display surface is fabricated by using multiple flexible substrates, mounting multiple micro-LEDs or multiple mini-LEDs on each of them, and then arranging them in a tile-like pattern.

[0021] Furthermore, before arranging them in a tile-like pattern, each of the multiple flexible substrates (or element layers) is cut with laser light. By controlling the depth with laser light, convex and concave portions are formed on the edge surfaces. As the laser light, continuous-wave laser light and pulsed-wave laser light can be used. In particular, pulsed-wave laser light is preferred because it can instantaneously emit high-energy pulsed laser light. Examples of pulsed-wave laser light that can be used include Ar lasers, Kr lasers, excimer lasers, CO2 lasers, YAG lasers, Y2O3 lasers, YVO4 lasers, YLF lasers, YAlO3 lasers, glass lasers, ruby ​​lasers, alexandrite lasers, Ti:sapphire lasers, copper vapor lasers, or gold vapor lasers. The wavelength of the laser light is preferably 200 nm to 20 μm. For example, a CO2 laser with a wavelength of 10.6 μm can be used as the laser light. CO2 lasers can process films or glass substrates made of organic or inorganic materials. Furthermore, when using pulsed laser light as the laser beam, 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 aspect of the present invention disclosed herein is a method for manufacturing an electronic device, comprising: forming a first pixel region having a first light-emitting diode chip on a first substrate; forming a second pixel region having a second light-emitting diode chip on a second substrate; arranging a plurality of first light-emitting diode chips adjacent to each other at equal intervals in the first pixel region in a first direction; and, before aligning the second light-emitting diode chips in the second pixel region to coincide with the first direction and arranging the first and second light-emitting diode chips side by side, scanning a laser beam in a second direction intersecting the first direction to partially cut off the edges of the first substrate and the first pixel region to form a convex portion; partially cutting off the edges of the second substrate and the second pixel region with a laser beam to form a concave portion; and fixing the first and second pixel regions adjacent to each other by fitting the convex portion and the concave portion together.

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

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

[0025] Furthermore, in the above configuration, 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 light-emitting elements, and in the pixel area, light-emitting elements that emit a first color of light, light-emitting elements that emit a second color of light, and light-emitting elements that emit a third color of light are mounted in a matrix. Multiple types of light-emitting diode chips can be arranged in a stripe, mosaic, or delta pattern. It is not limited to light-emitting elements that emit one type of light color on a single light-emitting diode chip, but it is also possible to pre-install light-emitting elements that emit three types of light colors on a single light-emitting diode chip.

[0027] One aspect of the present invention disclosed herein is an electronic device comprising a display device and a support, wherein 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 device may have a wiring layer in contact with the support, and this configuration comprises a display device and a support, the display device comprising a plurality of light-emitting diode chips and a flexible substrate on which the plurality of light-emitting diode chips are mounted, the support comprising a curved surface and a plurality of electrodes formed along the curved surface, the flexible substrate comprising a wiring layer electrically connected to the plurality of electrodes, and the plurality of light-emitting diode chips being electrically connected to the plurality of electrodes via the wiring layer, thus forming an electronic device.

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

[0030] In each of the above configurations, a substantially high-definition display device can be provided by devising the arrangement of the light-emitting elements. In this configuration, each of the multiple light-emitting diode chips has a light-emitting element, and in the pixel area, the first and second light-emitting elements are adjacent to each other in the first direction, the first and third light-emitting elements are adjacent to each other in the second direction, the fourth and fifth light-emitting elements are adjacent to each other in the first direction, the fourth and sixth light-emitting elements 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 to each other, the fourth to sixth light-emitting elements emit light of a different color to each other. [Effects of the Invention]

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

[0032] Alternatively, according to one aspect of the present invention, the manufacturing cost of a display device using microLEDs as display elements can be reduced. Alternatively, according to one aspect of the present invention, a display device using microLEDs as display elements can be manufactured with a high yield.

[0033] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one embodiment of the present invention does not necessarily have to possess all of these effects. Other effects will become clear 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. [Brief explanation of the drawing]

[0034] Figures 1A to 1C are examples of structural cross-sectional views illustrating one aspect of the present invention. Figures 2A to 2D are examples of process cross-sectional views illustrating one embodiment of the present invention. Figure 3A is a top view showing the pixel region before laser irradiation, and Figure 3B is an example of a perspective view showing a magnified portion of the pixel region. Figure 4 is an example of a top view illustrating one aspect of the present invention. Figure 5A is a partial cross-section of a display device using a curved surface microLED as a display element, illustrating one aspect of the present invention, and Figure 5B is a schematic diagram of the cross-section of the display device. Figures 6A1 and 6B1 are perspective views showing the method for manufacturing the display device, and Figures 6A2 and 6B2 are cross-sectional views showing the method for manufacturing the display device. Figures 7A1 and 7B1 are perspective views showing the method for manufacturing the display device, and Figures 7A2 and 7B2 are cross-sectional views showing the method for manufacturing the display device. Figures 8A1 and 8B1 are perspective views showing the method for manufacturing the display device, and Figures 8A2 and 8B2 are cross-sectional views showing the method for manufacturing the display device. Figures 9A1 and 9B1 are perspective views showing the method for manufacturing the display device, and Figures 9A2 and 9B2 are cross-sectional views showing the method for manufacturing the display device. Figures 10A1 and 10B1 are perspective views showing the method for manufacturing the display device, and Figures 10A2 and 10B2 are cross-sectional views showing the method for manufacturing the display device. Figure 11 is a perspective view of the device. Figure 12 is a schematic diagram showing the configuration of the device. Figures 13A to 13C are cross-sectional views showing a method for manufacturing a display device. Figures 14A to 14D are cross-sectional views showing a method for manufacturing a display device. Figure 15 is a schematic diagram of a cross-section of a modified display device. Figures 16A to 16C show examples of the configuration of a light-emitting element. Figure 17 shows an example of a cross-sectional structure of a display device. Figure 18A is a block diagram showing an example of a display device. Figures 18B to 18D show examples of pixel circuits. Figures 19A to 19D show examples of transistors. Figure 20 is a top view showing an example of a display device configuration. Figures 21A to 21D show examples of pixels. Figures 21E and 21F show examples of pixel circuit diagrams. Figure 22 shows an example of the interior configuration of a vehicle. Figure 23 shows an example of the interior configuration of a vehicle. Figures 24A and 24B illustrate one form of a light-emitting device. [Modes for carrying out the invention]

[0035] Embodiments of the present invention will be described in detail below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and its form and details can be modified in various ways. Furthermore, the present invention is not to be interpreted as being limited to the embodiments described below.

[0036] (Embodiment 1) In this embodiment, a configuration in which multiple flexible substrates on which multiple light-emitting diode chips are mounted are connected and then sealed with a substrate on which a nitride film is provided will be explained with reference to Figure 1.

[0037] Figure 1A shows a cross-sectional view of the end of the display device, where a flexible substrate 800 on which multiple light-emitting diode chips are mounted and a second substrate 801 on which multiple light-emitting diode chips are mounted are arranged side by side and fixed around the perimeter with resin 19, and further sandwiched on the outside by 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 on the third substrate 12a can be formed using sputtering, chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD). Alternatively, it can also be formed using atomic layer deposition (ALD), which causes less film formation damage. The nitride films 18a and 18b can be nitride insulating films, oxidative nitride insulating films, or nitride oxide insulating films, and examples include silicon nitride films, aluminum nitride films, silicon oxidative nitride films, aluminum oxidative nitride films, silicon oxide nitride films, or aluminum oxide nitride films. The thickness of the nitride films 18a and 18b is preferably between 1 nm and 500 nm.

[0038] In this specification, "oxide-nitride" refers to a material whose composition contains more oxygen than nitrogen, and "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, multiple light-emitting diode chips provided on the flexible substrate 800 and multiple light-emitting diode chips provided on the second substrate 801 are arranged at equal intervals to form a single pixel area.

[0040] The arrangement of the flexible substrate 800 and the second substrate 801 will be described in detail in Embodiment 2 below. The 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 shown here as a flat surface, when fixing it 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 that case, the entire display device (including at least the flexible substrate 800, the second substrate 801, the resin 19, the third substrate 12a, and the fourth substrate 12b) is bent and fixed.

[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 to each other across 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 making the resin 19, the third substrate 12a, and the fourth substrate 12b that overlap the two light emission paths—namely, the first light emission path passing through the third substrate 12a and the second light emission path passing through the fourth substrate 12b—all transparent materials, it becomes possible to display light emission from two directions. In addition, because the pixel area of ​​the display device is transparent, it can also be used as a so-called see-through display device.

[0045] Furthermore, Figure 1B shows a modified example of Figure 1A. Unlike Figure 1A, which uses two substrates for sealing, Figure 1B shows an example where a single substrate is folded for sealing. In Figure 1B, parts other than those sealed with a single substrate are identical to those in Figure 1A, so the same reference numerals are used for the same parts as in Figure 1A.

[0046] Because the product is sealed with a single substrate 12 instead of two, the number of components can be reduced, thereby lowering manufacturing costs. Furthermore, sealing with a single substrate 12 improves barrier properties.

[0047] Furthermore, Figure 1C shows an example different from Figures 1A and 1B. In Figure 1C, the edge of the flexible substrate 810 overlaps with the edge of the second substrate 811. In addition, a single folded substrate 12 is selectively provided with nitride films 18a and 18b.

[0048] In Figure 1C, the multiple light-emitting diode chips on the flexible substrate 810 and the multiple light-emitting diode chips on the second substrate 811 are arranged at equal intervals to form a single pixel area. The edge of the flexible substrate 810 is a surface separated by laser light. The second substrate 811 has an element layer, and the edge of both the element layer and the second substrate 811 are also surfaces separated by laser light. By cutting the edge of the substrate 810 with laser light before stacking the flexible substrate 810 and the second substrate 811, the boundary between the flexible substrate 810 and the second substrate 811 can be made less noticeable when the display device is activated.

[0049] Furthermore, an optical film may be provided separately. For example, if the light-emitting diode chip is a light-emitting element that emits ultraviolet light, a color conversion layer can be provided to realize a full-color display device. The color conversion layer should be provided in the path of the light in the direction of emission, and if there are two directions of emission, two color conversion layers (or color conversion films) should be provided so as 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 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 preferable to provide it on one side of the folded substrate 12. By providing a circularly polarizing film, the boundary between the flexible substrate 810 and the second substrate 811 can be made less noticeable when the display device is activated.

[0051] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0052] (Embodiment 2) In this embodiment, a display device and a method for manufacturing the same, which are aspects of the present invention, will be described.

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

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

[0055] The display device shown in Figure 5A has a flexible substrate 800 fixed to a curved support 10 via a resin 19. Pixel regions are formed on the flexible substrate 800, and light-emitting elements 17R, 17G, and 17B are provided in the pixel regions. The arrangement of light-emitting elements 17R, 17G, and 17B may be in a stripe, mosaic, or delta pattern. Alternatively, a white light-emitting element may be added to create a four-color arrangement of light-emitting elements.

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

[0057] Examples of flexible substrates 800 include acrylic resin, PET, polyester resins represented by PEN, polyacrylonitrile resin, polyimide resin, polymethyl methacrylate resin, PC resin, PES resin, polyamide resin (nylon, aramid), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, PTFE resin, and ABS resin. In particular, it is preferable to use a material with a low coefficient of thermal expansion, and for example, polyamide-imide resin, polyimide resin, polyamide resin, and PET can be suitably used. Furthermore, substrates in which resin is impregnated into a fibrous body, and substrates in which inorganic fillers are mixed into the resin to lower the coefficient of thermal expansion 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 thermal temperatures during the mounting of the micro-LED chip.

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

[0060] In Figure 5A, an example is shown in which each of the light-emitting elements 17R, 17G, and 17B is electrically connected to two electrodes, electrode 21 and electrode 23. However, the present invention is not limited to this. The number of electrodes electrically connected to the pixel circuit can be formed according to the number of electrodes that the light-emitting elements 17R, 17G, and 17B have. In this embodiment, the light-emitting elements 17R, 17G, and 17B are exemplified as components provided on the flexible substrate 800, but the term "light-emitting element" can be replaced with "light-emitting device." Similarly, the term "capacitive element" can be replaced with "capacitive device."

[0061] Figure 5B shows an example of a cross-sectional view of the light-emitting device when it is illuminated. Figure 5A is an enlarged view of the area 15 enclosed by the dashed line in Figure 5B. By arranging flexible substrates, each with a single pixel area formed on it, in a tile-like manner on the support 10, the display surface area can be increased. In Figure 5B, four light-emitting panels are fixed with resin 19. For example, to obtain a full-color display device, a portion of a flexible substrate with red, green, and blue light-emitting elements mounted in a matrix to form a pixel area is designated as light-emitting panel 16a. 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 are also shown. Furthermore, a cover material 13 is provided to cover the four light-emitting panels so that the boundaries of the pixel areas are not noticeable. The cover material 13 does not need to be provided if it is not particularly necessary. The support 10 can also be called a housing or support member, and is a member that has a curved surface in at least a part of it. When a display device is installed inside a vehicle, the support 10 is made of plastic, metal, glass, or rubber. Although the support 10 is shown here as a plate, it is not particularly limited and can be any member having at least a curved surface. A wiring layer may be provided on the support 10, and the wiring contained in the wiring layer is electrically connected to the electrodes of the light-emitting panel. The wiring layer may have wiring, an insulating film covering the wiring, and electrodes with openings in the insulating film that connect to the wiring. The wiring contained in the wiring layer functions as auxiliary wiring, connecting wiring, power lines, signal lines, or fixed potential lines. The wiring of the wiring layer can be formed on the curved support 10 using known techniques. For example, the wiring layer can be formed on the support 10 using a method of selectively forming silver paste, a transposition method, or a transfer method.

[0062] Next, a method for fabricating a display device by arranging the respective pixel regions provided on two flexible substrates will be explained using Figure 2.

[0063] Figure 2A is a schematic cross-sectional view of the stage in which a laser beam is shone on the edges after a light-emitting diode chip has been mounted on a flexible substrate 800. Prior to this, an element layer 820 containing electrodes or transistors is formed on the flexible substrate 800, and multiple types of light-emitting diode chips are arranged in a matrix at equal intervals. Due to handling limitations, it is difficult to place the element layer 820 or light-emitting diode chips on the peripheral edge of a single flexible substrate 800, resulting in areas at the peripheral edge where no elements are formed. Therefore, a laser beam is shone to cut off a portion of the element layer 820 (the edge of the pixel area) along the laser irradiation line 700. Additionally, a portion of the flexible substrate 800 is cut off by shifting its position parallel to the laser irradiation line 700. Note that, although the element layer 820 is described here as not containing LEDs, it is not particularly limited and may be referred to as an element layer 820 containing LEDs.

[0064] Figure 2B shows the state after irradiation. Then, by controlling the depth of the laser beam irradiation position and performing a scan, a portion is removed as shown in Figure 2C, forming a protruding convex portion on the end face of the flexible substrate 800.

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

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

[0067] By fitting the protrusions of the flexible substrate 800 into the recesses of the second substrate 801, the bonding surface is increased, making it easier to fix the components in place. Furthermore, even when the spacing between light-emitting diode chips is narrow, the chips can be fixed in a regular, evenly spaced arrangement in one direction. Therefore, large-area display devices can be manufactured. The element layer 821 provided on the second substrate 801 may be configured to electrically connect the wiring or electrodes included in the element layer 820 provided on the flexible substrate 800 with the wiring or electrodes included in the element layer 820.

[0068] Figure 3A is a top view of the display device before laser irradiation. In the display device shown in Figure 3A, a pixel region 702, a source driver circuit 706, and a gate driver circuit 704 are provided on a flexible substrate 801, which is a first substrate. The element layer provided on the flexible substrate 800 can include these pixel region 702, source driver circuit 706, and gate driver circuit 704. The source driver circuit 706 and gate driver circuit 704 may also be mounted as drive ICs. In addition, as shown in Figure 3B, a plurality of light-emitting diode chips 17 are provided in the pixel region 702. 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, the manufacturing methods for each display device will be explained using Figures 6A1 to 14D. Figures 6A1 to 14D are perspective views and cross-sectional views of each stage in the manufacturing process of the display device.

[0070] The light-emitting color of the LED chip that can be used in the method for manufacturing a display device, which is one aspect of the present invention, is not particularly limited. For example, it can be applied to LED chips that emit white light. It can also be applied to LED chips that emit light in the visible light wavelength range of red, green, and blue. It can also be applied to LED chips that emit light in the near-infrared, infrared, and ultraviolet wavelength ranges. When using LED chips that emit light in the near-infrared, infrared, and ultraviolet wavelength ranges, only one type of LED chip is arranged, and a color conversion layer or color conversion film is layered on top of it. When layering the color conversion layer or color conversion film, 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, so no irregularities are created on the surface of the color conversion layer or color conversion film, which is preferable.

[0071] This embodiment describes a micro-LED having a double heterojunction. However, there are no particular limitations on the light-emitting diode; for example, a micro-LED having a quantum well junction or an LED using a nanocolumn may be used.

[0072] The area of ​​the region that emits light from the light-emitting diode is 1 mm². 2 The following is preferred: 10,000 μm 2 The following is more preferable: 3000 μm 2 The following is more preferable: 700 μm 2 The following is even more preferable: The area of ​​the region is 1 μm². 2 The above is preferable, and 10 μm 2 The above is preferable, and 100 μm 2 The above is even more preferable.

[0073] Furthermore, the LEDs that can be used in the display device according to one aspect of the present invention are not limited to the above-mentioned micro-LEDs. For example, the area of ​​the light-emitting region is 10,000 μm². 2 Larger light-emitting diodes (also called mini-LEDs) may be used. Note that a mini-LED refers to a light-emitting diode with a rectangular planar shape and a chip size where at least one side is 0.1 mm or larger.

[0074] The display device of this embodiment preferably has a transistor having a channel-forming region in the metal oxide layer. Transistors using a metal oxide layer can have low power consumption. Therefore, by combining them with a micro-LED, a display device with extremely low power consumption can be realized. A micro-LED refers to a light-emitting diode with a rectangular planar shape and a chip size in which at least one side is less than 0.1 mm.

[0075] Multiple LED chips are formed on the LED chip substrate. An example of the LED chip substrate 900 is shown in Figures 6A1 and 6A2. Figure 6A1 is a perspective view of the LED chip substrate 900, and Figure 6A2 is a cross-sectional view along the dashed line X1-X2 shown in Figure 6A1. The LED chip has a semiconductor layer 81 having an n-type semiconductor layer, an emissive layer, and a p-type semiconductor layer, an electrode 85 that functions as a cathode, and an electrode 87 that functions as an anode formed on the substrate 71A. Multiple LED chips are formed on the LED chip substrate 900, and multiple LED chips can be manufactured by separating the LED chip substrate 900 along the LED chip section 51A.

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

[0077] The grinding process is explained in detail. First, the electrode 85 and electrode 87 sides of the LED chip substrate 900 are attached to the plate 903. The attached LED chip substrate 900 and plate 903 are placed on the table 905. At this time, the plate 903 side is in 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, the grinding wheel 907 attached to the grinding wheel 909 is brought into contact with the substrate 71A to grind it into substrate 71. During grinding, the grinding wheel 909 and grinding wheel 907 may also be rotated.

[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 (Figures 7A1 and 7A2). Flattening the surface of the substrate 71 helps to suppress a decrease in yield in subsequent processes.

[0079] Furthermore, when performing grinding and polishing, it is preferable to attach and fix a protective film 901 to the electrode 85 and electrode 87 sides before polishing (see Figure 6B2). After polishing, remove the film 901.

[0080] Next, the first film 919 is provided on the electrode 85 and electrode 87 sides, and the LED chip substrate 900 and the first film 919 are fixed to the first fixing device 921 (Figures 7B1 and 7B2). It is preferable to use a film that has the property of stretching when pulled (also called an expanded film) as the first film 919. As the first film 919, vinyl chloride resin, silicone resin, and polyolefin resin can be used. Furthermore, it is preferable that the first film 919 has an adhesive on its surface and that its adhesive strength weakens when irradiated with light. Specifically, a film whose adhesive strength weakens when irradiated with ultraviolet light can be suitably used as the first film 919. As the first fixing device 921, for example, a ring-shaped jig as shown in Figure 7B1 can be suitably used.

[0081] Next, a scribe line 911 is formed along the LED chip section 51A of the LED chip substrate 900 (Figures 8A1 and 8A2). A machine scribe method can be used to form the scribe line 911. In the machine scribe method, a groove (also called a scribe line or marking) is mechanically formed on the substrate 71 by pressing a scribe tool against the substrate 71. A diamond blade can be used as the scribe tool.

[0082] Furthermore, a laser scribing method may be used to form the scribe line 911. The laser scribing method is a method in which a modified layer is created on the substrate 71 by generating thermal stress through the thermal stress caused by irradiating the substrate 71 with laser light to heat it locally and then rapidly cooling it, thereby forming the scribe line 911. In the laser scribing method, the scribe line 911 may be formed on the surface of the substrate 71, or it may be formed inside the surface of the substrate 71. In the machine scribing method, the scribe tool needs to be replaced due to wear, but in the laser scribing method, the scribe tool does not need to be replaced.

[0083] Alternatively, the substrate 71 may be cut along the LED chip section 51A using the blade dicing method. The blade dicing method allows for cutting into an object by rotating a blade (also called a cutting tool) at high speed, and a diamond can be used for the blade. When using the blade dicing method, the cutting may be a half-cut, where the cut is made partway through the thickness of the substrate 71, or a full-cut, where the substrate 71 and the semiconductor layer 81 are completely cut 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 base 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 (Figures 8B1 and 8B2). Alternatively, the LED chip substrate 900 may be sandwiched between rollers, and the rollers may be provided with surfaces at different inclination angles to separate the LED chips. When separating the LED chips, a protective sheet 923 (also called a scribe sheet) may be placed on the substrate 71 side before separating the LED chips. The LED chip substrate 900 after being separated into individual LED chips is shown in Figures 9A1 and 9A2.

[0085] Next, the first film 919 is pulled to separate each LED chip 51 and widen the spacing between the LED chips 51 (Figures 9B1 and 9B2). Widening 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 on which the LED chips 51 are located is pushed up from the first film 919 side towards the LED chip 51 side, thereby pulling the first film 919 and separating each LED chip 51.

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

[0087] If already separated LED chips 51 are used, the manufacturing of the display device may begin from the steps shown in Figures 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 the second fixing device 925, allowing the process to proceed to the steps described below. In this case, as shown in Figures 10A1 and 10A2, it is preferable to provide a gap between each LED chip 51 to improve the accuracy of the subsequent mounting process and enable the manufacturing of the display device 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 irradiated from the first film 919 side to separate the first film 919 and the first fixing device 921 from the LED chip 51 (Figures 10B1 and 10B2). In the process of separating the LED chip as described above, the first film 919 may stretch and bend. By separating the LED chip 51 from the first film 919 and re-fixing it to the second film 927, the bending of the second film 927 can be reduced. Furthermore, by reducing the bending of the second film 927, the accuracy of the subsequent mounting process can be improved, and display devices can 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 force is applied and tries to return 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, and 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 so that the LED chip substrate 900 can be fixed to the second film 927. As the second fixing device 925, for example, a ring-shaped jig as shown in Figure 10B1 can be suitably used.

[0090] It is preferable to inspect the LED chip 51 at this point. Visual inspection can be used to inspect the LED chip 51. Alternatively, a voltage may be applied between electrodes 85 and 87 to inspect the light emission state from the LED chip 51. For LED chips 51 determined to be defective during inspection, it is preferable to obtain their position information within the second film 927. By obtaining the position information of defective products, the defective products can be excluded from the mounting process in subsequent mounting steps.

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

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

[0093] Stage 951 has the function of fixing the flexible substrate 800. For example, a vacuum suction mechanism can be used to fix the flexible substrate 800. Stage 951 can be moved in the XY direction on a plane parallel to the surface of the flexible substrate 800 by uniaxial robots 953 and 955.

[0094] The gripping mechanism 959 grips the second fixing device 925, which holds the LED chip 51 and the second film 927. The gripping mechanism 959 also has the function of moving the second fixing device 925, which holds the LED chip 51 and the second film 927, to any desired position.

[0095] The extrusion mechanism 929 has the function of moving up and down and positioning the LED chip 51 on the flexible substrate 800. The extrusion mechanism 929 has a columnar shape (including cylindrical and polygonal columnar shapes), and the side that contacts the LED chip 51 may be tapered. Preferably, the diameter of the tip of the extrusion mechanism 929 that contacts the LED chip 51 is smaller than the width of the LED chip 51.

[0096] The control device 961 has functions to control the single-axis robot 953, the single-axis robot 955, the gripping mechanism 959, and the extrusion mechanism 929, respectively. In addition, the control device 961 receives the position information of LED chips that were determined to be defective in the LED chip inspection process described above. By receiving the position information of defective products into the control device 961, defective products can be excluded from the mounting target.

[0097] The device 950 preferably includes an alignment mechanism for the camera 957. The position of the second fixing device 925 is controlled based on an alignment marker provided on the flexible substrate 800.

[0098] A method for mounting the LED chip 51 onto a flexible substrate 800 will be explained in detail using Figures 13 and 14.

[0099] First, a plurality of LED chips 51 fixed to the second film 927 are placed facing each other on a flexible substrate 800. When placing them facing each other, it is preferable to detect the contour of the LED chips 51 with a camera 957 and acquire the position information of the LED chips 51. From the position information of the LED chips 51, the position of the LED chips 51 is adjusted by a gripping mechanism 959 to align the electrodes 85 and 87 of the LED chips 51 with the electrodes 21 and 23 on the flexible substrate 800 (Figure 13A). It is preferable that the gripping mechanism 959 can move 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 positions of the electrodes 21 and 23 on the flexible substrate 800 can be aligned with high precision.

[0100] In Figure 12, a camera 957 is positioned above the second film 927, and the positions of electrodes 85 and 87 of the LED chip 51 are detected from above the second film 927. However, the present invention is not limited to this configuration. Furthermore, a camera (not shown) may be positioned below the flexible substrate 800, and the positions of electrodes 85 and 87 of the LED chip 51, as well as electrodes 21 and 23 on the flexible substrate 800, may be detected from below the flexible substrate 800.

[0101] Next, the extrusion mechanism 929 is pushed from the second film 927 side toward the flexible substrate 800, bringing electrodes 85 and 21, and 87 and 23 into contact. Subsequently, ultrasonic waves are applied to the extrusion mechanism 929 to press electrodes 85 and 21, and electrodes 87 and 23 together (Figure 13B). Alternatively, the extrusion mechanism 929 may be heated to press electrodes 85 and 21, and electrodes 87 and 23 together by heat. Alternatively, pressing may be performed using both ultrasonic waves and heat. When heating the extrusion mechanism 929, it is preferable to keep the temperature of the extrusion mechanism 929 below the heat resistance temperature of the second film 927. By keeping the temperature of the extrusion mechanism 929 below the heat resistance 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 unit 963 shown in Figure 12. Unit 963 has an ultrasonic oscillator and can apply ultrasonic waves to the extrusion mechanism 929. Alternatively, unit 963 has a heating mechanism and can apply heat to the extrusion mechanism 929. Alternatively, unit 963 may have both an ultrasonic oscillator and a heating mechanism, applying ultrasonic waves and heat to the extrusion mechanism 929. Unit 963 is connected to a control device 961, which controls the timing of ultrasonic wave application and heating.

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

[0104] Next, the extrusion mechanism 929 is separated from the second film 927 (Figure 13C). Due to the pressure bond between electrode 85 and electrode 21, and electrode 87 and electrode 23, the LED chips 51 mounted on electrode 21 and electrode 23 are separated from the second film 927. Preferably, the adhesive strength of the adhesive provided on the surface of the second film 927 is less than the pressure bond between electrode 85 and electrode 21, and electrode 87 and electrode 23. By using an adhesive with an adhesive strength weaker than the pressure bond on the second film 927, the LED chips 51 can be efficiently mounted on the flexible substrate 800, thereby reducing the manufacturing cost of the display device.

[0105] In this case, 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 can lead to poor conductivity between electrodes 85 and 87 and electrodes 21 and 23. In one aspect of the present invention, the second film 927 is elastic, and when the extrusion mechanism 929 is removed from the second film 927, the second film 927 returns to its original shape. By returning the second film 927 to its original shape, bending of the second film 927 can be suppressed, and the positions of electrodes 85 and 87 and 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 aligning the LED chip 51. This allows for the production of display devices with a high yield and reduces 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 (Figure 14A). During alignment, one or more of the stage 951, gripping mechanism 959, and extrusion mechanism 929 can be moved. It is even more preferable to move two or more of the stage 951, gripping mechanism 959, and extrusion mechanism 929. By moving two or more of the stage 951, gripping mechanism 959, and extrusion mechanism 929, the accuracy of the 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 extrusion 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 with electrode 23. Subsequently, electrode 85 and electrode 21, and electrode 87 and electrode 23 are pressed together (Figure 14B). Then, the extrusion mechanism 929 is moved onto the second film 927. As a result, the LED chips 51 mounted on electrode 21 and electrode 23 are separated from the second film 927 (Figure 14C).

[0108] The above operation is repeated to mount LED chips across the entire pixel area of ​​the flexible substrate 800. Note that LED chips 51B that are determined to be defective during the LED chip inspection process have their position information incorporated into the control device 961 and are not mounted on the flexible substrate 800 (Figures 14C and 14D). By incorporating the positions of defective LED chips into the control device 961, only good LED chips 51 can be mounted on the flexible substrate 800. Furthermore, a step of reflow soldering under a nitrogen atmosphere after mounting to melt the solder and create an alloy may be added.

[0109] In a method for manufacturing a display device according to one aspect of the present invention, it is also possible to provide multiple types of LED chips 51 emitting colors in different wavelength ranges on a flexible substrate 800. For example, the case in which LED chips 51 emitting red light (hereinafter referred to as red light), LED chips 51 emitting green light (hereinafter referred to as green light), and LED chips 51 emitting blue light (hereinafter referred to as blue light) are provided on a flexible substrate 800 will be described. Multiple LED chips 51 emitting red light are mounted on the flexible substrate 800 using a second film 927 and a second fixing device 925 to which the LED chips 51 emitting red light are fixed. Next, multiple LED chips 51 emitting green light are mounted on the flexible substrate 800 using a second film 927 and a second fixing device 925 to which the LED chips 51 emitting green light are fixed. Next, the LED chips 51 emitting blue light are mounted onto a flexible substrate 800 using a second film 927 and a second fixing device 925 to which the LED chips 51 emitting blue light are fixed. In this way, LED chips 51 emitting red light, LED chips 51 emitting green light, and 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 an LED chip 51 is mounted on a flexible substrate 800 using a set of second films 927 and second fasteners 925, the present invention is not limited to this embodiment. The LED chip 51 may be mounted using multiple sets of second films 927 and second fasteners 925. Such a configuration allows for the production of a display device with high productivity. If the LED chip 51 emits monochromatic light, it functions as a sub-pixel, and by arranging multiple types of LED chips 51, one pixel is formed, and arranging these pixels in a matrix constitutes a pixel area. If the LED chip 51 has multiple light-emitting elements, the multiple light-emitting elements become sub-pixels, and one LED chip 51 constitutes a pixel.

[0111] In this embodiment, an example using an extrusion mechanism 929 is shown, but it is not limited to this, and an apparatus that mounts LED chips across the entire pixel area of ​​a flexible substrate 800 by selectively irradiating it with laser light and performing laser ablation may also be used.

[0112] Then, a flexible substrate 800 on which LED chips are mounted across the entire pixel area is fixed to a curved support using resin 19 to bond it, thereby obtaining a display device.

[0113] When increasing the area, multiple substrates 800 can be arranged to create a display device in which a pixel area of ​​m rows and n columns (n ​​is a natural number greater than or equal to 1) forms a single display surface.

[0114] The above is a description of the method for manufacturing the display device.

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

[0116] In the display device shown in Figure 15, the fifth light-emitting panel 16e, the sixth light-emitting panel 16f, the seventh light-emitting panel 16g, and the eighth light-emitting panel 16h are arranged and fixed to the concave side of the support 11. Here, it is referred to as the fifth light-emitting panel 16e to avoid confusion with Figure 5B, but it essentially 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] Furthermore, although Figures 5A, 5B, and 15 illustrate the use of a support having a uniform radius of curvature, the invention is not particularly limited. The display surface does not have to be entirely curved; it may be partially flat to match the internal components of the vehicle (dashboard, ceiling, pillars, windows, steering wheel, seats, or the inside of the doors), or it may be configured to have a display surface with a mixture of convex and concave shapes. For example, a display device according to one embodiment of the present invention can be installed on the interior wall of a car, specifically the dashboard, ceiling, or wall. Since a display device according to one embodiment of the present invention can have a display surface with a large display area, it can display relatively large maps and can be used not only in cars but also as a navigation device for vehicles (aircraft or submarines).

[0118] Furthermore, by incorporating a touch sensor into the display surface, the display surface becomes one that can be operated by the driver's fingers. Therefore, a display device with a touch sensor can also be considered a vehicle control device.

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

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

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

[0122] As described above, by adopting the configuration of one aspect of the present invention, a display device with high display quality can be provided. Alternatively, by adopting the configuration of one aspect of the present invention, the degree of design freedom for the display device can be increased, and the design quality of the display device can be improved.

[0123] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

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

[0125] The LED chip has a light-emitting diode. The configuration of the light-emitting diode is not particularly limited and may be an MIS (Metal Insulator Semiconductor) junction, or a homo, hetero, or double hetero structure having a PN junction or PIN junction can be used. It may also be a superlattice structure, a single quantum well structure or a multi-quantum well (MQW) structure with stacked thin films that produce quantum effects. Furthermore, an LED chip using nanocolumns may also be used.

[0126] Examples of LED chips are shown in Figures 16A and 16B. Figure 16A is a cross-sectional view of the LED chip 51, and Figure 16B is a top view of the LED chip 51. The LED chip 51 has a semiconductor layer 81. The semiconductor layer 81 has an n-type semiconductor layer 75, an emissive layer 77 on the n-type semiconductor layer 75, and a p-type semiconductor layer 79 on the emissive layer 77. As the material for the p-type semiconductor layer 79, a material with a larger bandgap energy than the emissive layer 77 and capable of confining carriers to the emissive layer 77 can be used. The LED chip 51 also has 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. It is also preferable that the top and side surfaces of the electrode 83 are covered with an insulating layer 89. The insulating layer 89 functions as a protective film for the LED chip 51.

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

[0128] The light-emitting layer 77 can utilize a multiple quantum well (MQW) structure in which a barrier layer 77a and a well layer 77b are stacked multiple times. Preferably, the barrier layer 77a is made of a material with a larger bandgap energy than the well layer 77b. With this configuration, energy can be confined to the well layer 77b, improving quantum efficiency and thus improving the luminous efficiency of the LED chip 51.

[0129] In a face-up type LED chip 51, the electrode 83 can be made of a light-transmitting material, such as ITO (In2O3-SnO2), AZO (Al2O3-ZnO), In-Zn oxide (In2O3-ZnO), GZO (GeO2-ZnO), or ICO (In2O3-CeO2). In a face-up type LED chip 51, light is mainly emitted towards the electrode 87. In a face-down type LED chip 51, the electrode 83 can be made of a light-reflecting material, such as silver, aluminum, or rhodium. In a face-down type LED chip 51, light is mainly emitted towards the substrate 71.

[0130] As the substrate 71, oxide single crystals such as sapphire single crystal (Al2O3), spinel single crystal (MgAl2O4), ZnO single crystal, LiAlO2 single crystal, LiGaO2 single crystal, and MgO single crystal, as well as boride single crystals such as Si single crystal, SiC single crystal, GaAs single crystal, AlN single crystal, GaN single crystal, and ZrB2 can be used. In a face-down type LED chip 51, it is preferable to use a light-transmitting material for the substrate 71, and for example, a light-transmitting sapphire single crystal can be used.

[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 mitigating the difference in lattice constants 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 electrode 85 and the electrode 87 are arranged on the same surface side as shown in FIG. 16A. By providing the electrode 85 and the electrode 87 of the LED chip 51 on the same surface side, connection with the electrode 21 and the electrode 23 is facilitated, and the structure of the electrode 21 and the electrode 23 can be simplified. Furthermore, the LED chip 51 that can be used as the light-emitting diode chip 17 is preferably of a face-down type. By using the face-down type LED chip 51, light emitted from the LED chip 51 can be efficiently emitted toward the display surface side of the display device, whereby a display device with high luminance can be obtained. A commercially available LED chip may be used as the LED chip 51.

[0133] To obtain white light emission, a phosphor layer is used. As the phosphor included in the phosphor layer, an organic resin layer having a phosphor printed or coated on its surface, or an organic resin layer mixed with a phosphor can be used. For the phosphor layer, a material that is excited by light emitted from the LED chip 51 and emits light of a complementary color to the emission color of the LED chip 51 can be used. With such a configuration, the light emitted by the light-emitting diode chip 17 and the light emitted by the phosphor are combined, so that white light can 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 a complementary color to blue, a configuration in which white light is emitted from the phosphor layer can be achieved. As the LED chip 51 capable of emitting blue light, a diode made of a group 13 nitride compound semiconductor is typical, for example In x Al y Ga 1-x-y N (where x is 0 or more and 1 or less, y is 0 or more and 1 or less, and x+y is 0 or more and 1 or less), there is a diode having a GaN-based material represented by the formula. Representative examples of phosphors that are excited by blue light and emit yellow light include Y3Al5O 12 :Ce (YAG:Ce), and (Ba,Sr,Mg)2SiO4: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, can be used to create a configuration in which white light is emitted from the phosphor layer.

[0136] The phosphor layer may have multiple types of phosphors, and each phosphor may emit light of a different color. For example, a configuration can be used in which white light is emitted from the phosphor layer by using an LED chip 51 that emits blue light, a phosphor that emits red light, and a phosphor that emits green light. Typical examples of phosphors that are excited by blue light and emit red light include (Ca,Sr)S:Eu and Sr2Si7Al3ON. 13 There is :Eu. Typical examples of phosphors that are excited by blue light and emit green light include SrGa2S4:Eu and Sr3Si 13 Al3O2N 21 :Eu exists.

[0137] Furthermore, a configuration can be achieved in which white light is emitted from a phosphor layer by using an LED chip 51 that emits near-ultraviolet or violet light, and phosphors that emit red light, green light, and blue light. Typical examples of phosphors that are excited by near-ultraviolet or violet light and emit red light include (Ca,Sr)S:Eu and Sr2Si7Al3ON. 13 Examples include :Eu and La2O2S:Eu. Representative examples of phosphors that are excited by near-ultraviolet or violet light and emit green light include SrGa2S4:Eu and Sr3Si 13 Al3O2N 21 :Eu is present. A typical example of a phosphor that is excited by near-ultraviolet or violet light and emits blue light is Sr 10 (PO4)6Cl2:Eu, (Sr,Ba,Ca) 10 (PO4)6Cl2:Eu is present.

[0138] Near-ultraviolet light has its maximum peak in the emission spectrum at wavelengths of 200 nm to 380 nm. Violet light has its maximum peak in the emission spectrum at wavelengths of 380 nm to 430 nm. Blue light has its maximum peak in the emission spectrum at wavelengths of 430 nm to 490 nm. Green light has its maximum peak in the emission spectrum at wavelengths of 490 nm to 550 nm. Yellow light has its maximum peak in the emission spectrum at wavelengths of 550 nm to 590 nm. Red light has its maximum peak in the emission spectrum at wavelengths of 640 nm to 770 nm.

[0139] When using an LED chip 51 that emits blue light and has a phosphor layer that emits yellow light, it is preferable that the light emitted by the LED chip 51 has a maximum peak in its emission spectrum at a wavelength of 330 nm to 500 nm, more preferably at a wavelength of 430 nm to 490 nm, and even more preferably at a wavelength of 450 nm to 480 nm. This allows for efficient excitation of the phosphor. Furthermore, by having a maximum peak in the emission spectrum of the light emitted by the LED chip 51 at 430 nm to 490 nm, the blue light used for excitation and the yellow light from the phosphor can be mixed to produce white light. Moreover, by having a maximum peak in the light emitted by the LED chip 51 at 450 nm to 480 nm, a highly pure white light can be achieved.

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

[0141] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

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

[0143] Figure 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 resin 732.

[0145] A pixel region 702 is provided on the first substrate 745. Multiple light-emitting elements 782 are provided in the pixel region 702.

[0146] The configuration of the transistors in the pixel region 702 is not particularly limited. Single-crystal semiconductors, polycrystalline semiconductors, microcrystalline semiconductors, or amorphous semiconductors can be used as the semiconductor layers of the transistors, either individually or in combination. Examples of semiconductor materials include silicon and germanium. Compound semiconductors represented by silicon germanium, silicon carbide, gallium arsenide, oxide semiconductors, nitride semiconductors, or organic semiconductors can also be used.

[0147] When using an organic semiconductor as the semiconductor layer, low-molecular-weight organic materials with aromatic rings or π-electron conjugated conductive polymers can be used. For example, rubrene, tetracene, pentacene, perylenediimide, tetracyanoquinodimethane, polythiophene, polyacetylene, and poly(p-phenylenevinylene) can be used.

[0148] In this embodiment, it is preferable that the transistor used has an oxide semiconductor film that has been purified to suppress the formation of oxygen vacancies. This transistor can reduce the off-current. Therefore, the holding time of the electrical signal (image signal) can be extended, and the writing interval can also be set to be longer in the ON state. Therefore, the frequency of refresh operations can be reduced, resulting in the effect of reducing power consumption.

[0149] Furthermore, transistors using oxide semiconductor films (also called OS transistors) can achieve relatively high field-effect mobility, enabling high-speed operation. Additionally, using high-speed transistors in the pixel region allows for the provision of high-quality images.

[0150] Transistors using oxide semiconductor films can be fabricated as appropriate using known techniques and are not particularly limited. In Figure 17, transistor 750 can be considered a type of top-gate transistor with a back gate electrode. The potential of the back gate electrode may be the same as the gate electrode, the ground potential (GND potential), or any other potential. Furthermore, the threshold voltage of the transistor can be changed by independently changing the potential of the back gate electrode without linking it to the gate electrode.

[0151] Furthermore, since the gate electrode and back gate electrode are formed from conductive layers, they have the function of preventing electric fields 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). The electric field shielding function can be enhanced by making the back gate electrode larger than the semiconductor layer and covering the semiconductor layer with the back gate electrode.

[0152] The display device 700A shown in Figure 17 includes a routing section 711, a pixel area 702, and a gate driver circuit section 704. The routing section 711 has signal lines 710. The pixel area 702 has a transistor 750 and a capacitive element 790. The gate driver circuit section 704 has a transistor 752. Although not shown here, a source driver circuit section may also be provided, and the source driver circuit section has a transistor. Furthermore, the gate driver circuit section 704 and the source driver circuit section may not be provided on the first substrate 745, but may be mounted as ICs in another part.

[0153] The capacitive element 790 shown in Figure 17 has 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. Furthermore, a portion of the insulating film that functions as the first gate insulating layer of the transistor 750 is provided between the lower electrode and the upper electrode. In other words, the capacitive element 790 has a laminated structure in which an insulating film that functions as a dielectric film is sandwiched between a pair of electrodes. In addition, wiring obtained by processing the same film as the source and drain electrodes of the transistor is connected to the upper electrode.

[0154] Furthermore, an insulating layer 770 is provided on transistors 750 and 752, and on the capacitive element 790. The insulating layer 770 functions as a planarizing film, and can flatten the upper surfaces of the conductive layers 772 and 774 provided on the insulating layer 770. Because the conductive layers 772 and 774 are located on the same plane and their upper surfaces are flat, the conductive layers 772 and 774 and the light-emitting element 782 can be easily electrically connected.

[0155] The conductive layers 772 and 774 and the light-emitting element 782 are electrically connected via conductive bumps 791 and 793. Figure 17 shows a configuration in which the cathode and anode electrodes of the light-emitting element 782 are at different heights, and the bumps 791 and 793 are at different heights. If the cathode and anode electrodes of the light-emitting element 782 are at the same height, the bumps 791 and 793 can be configured to be approximately the same height.

[0156] As shown in Figure 17, it is preferable that the transistor 750 in the pixel region 702 be provided so as to overlap the conductive layer 772. By having a region where the transistor 750, particularly the channel formation region, and the conductive layer 772 overlap, it is possible to suppress the light emitted from the light-emitting element 782 and ambient light from reaching the transistor 750, thereby suppressing fluctuations in the electrical characteristics of the transistor 750.

[0157] The transistor 750 in the pixel region 702 and the transistor 752 in the gate driver circuit 704 may be transistors of different structures. For example, one may be a top-gate type transistor and the other a bottom-gate type transistor. The same applies to the source driver circuit 704 as to the gate driver circuit 704.

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

[0159] Since a flexible substrate is used for the first substrate 745, it is preferable to provide an insulating layer that has barrier properties against water or hydrogen between the first substrate 745 and the transistor 750. The structure also has a laminated configuration of the first substrate 745, adhesive layer 742, resin layer 743, and insulating layer 744. The transistor 750 or capacitive element 790 is provided on the insulating layer 744 which is provided on the resin layer 743. The resin layer 743 and the first substrate 745 are bonded together by the adhesive layer 742. It is preferable that the resin layer 743 is 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 component (e.g., a scattering plate), an input device such as a touch sensor panel, or a configuration in which two or more of these are laminated together.

[0161] Furthermore, a light-shielding layer 738, a colored layer 736, and a phosphor layer 797 are provided on the second substrate 740. The colored layer 736 is provided on the light-emitting element 782. The phosphor layer 797 is provided between the light-emitting element 782 and the colored layer 736. The phosphor layer 797, the light-emitting element 782, and the colored layer 736 have overlapping regions. As shown in Figure 17, it is preferable that the edge of the phosphor layer 797 is located outside the edge of the light-emitting element 782, and the edge of the colored layer 736 is located outside the edge of the phosphor layer 797. With this configuration, light leakage to adjacent pixels and color mixing between pixels can be suppressed. In addition, by providing a light-shielding layer 738 between adjacent colored layers 736, reflection of ambient light can be reduced, resulting in a display device with high contrast.

[0162] For example, by configuring the phosphor layer 797 to have 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 a light-emitting element 782 located in a region overlapping with a colored layer 736 that transmits red light passes through the phosphor layer 797 and the colored layer 736 and is emitted as red light towards the display surface. Similarly, light emitted by a light-emitting element 782 located in a region overlapping with a colored layer 736 that transmits green light is emitted as green light. Light emitted by a light-emitting element 782 located in a region overlapping with a colored layer 736 that transmits blue light is emitted as blue light. This makes it possible to perform color display using only 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. In other words, according to one aspect of the present invention, a display device can be made with low manufacturing costs, high brightness and contrast, fast response speed, and low power consumption.

[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, thereby emitting white light from the phosphor layer 797.

[0164] Alternatively, 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 violet light, thereby emitting white light from the phosphor layer 797.

[0165] The display device 700A shown in Figure 17 has a light-emitting element 782. It is preferable to use a face-down type LED chip as the light-emitting element 782.

[0166] Furthermore, the colored layer 736 is provided in a position overlapping with the light-emitting element 782, and the light-shielding layer 738 is provided in a position overlapping with the edge of the colored layer 736, in the routing wiring section 711, and in the gate driver circuit section 704. In addition, the space between the phosphor layer 797, the colored layer 736, the light-shielding layer 738 and the light-emitting element 782 is filled with resin 732.

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

[0168] The thin films (insulating films, semiconductor films, conductive films) that make up the display device can be formed using sputtering, chemical vapor deposition (CVD), vacuum deposition, pulsed laser deposition (PLD), and atomic layer deposition (ALD). Plasma chemical vapor deposition (PECVD) and thermal CVD are also acceptable CVD methods. Metal-organic chemical vapor deposition (MOCVD) can be used as an example of thermal CVD.

[0169] Furthermore, spin coating, dipping, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, and knife coating can be used to form the thin films (insulating films, semiconductor films, conductive films) that constitute the display device.

[0170] Furthermore, when processing the thin films that constitute the display device, the processing can be done using photolithography. Alternatively, island-shaped thin films may be formed by a film deposition method using a shielding mask. Alternatively, the thin films may be processed by nanoimprint, sandblasting, or lift-off methods. Two examples of photolithography methods are as follows: One method involves coating the thin film to be processed with a photosensitive resist material, exposing it through a photomask, developing it to form a resist mask, processing the thin film by etching, and removing the resist mask. The other method involves depositing a photosensitive thin film, then exposing and developing it to process the thin film into the desired shape.

[0171] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture thereof. Other options include ultraviolet light, KrF laser light, or ArF laser light. Exposure may also be performed using immersion lithography. Furthermore, extreme ultraviolet (EUV) light or X-rays may be used as the light source for exposure. An electron beam can also be used instead of the light source. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because it allows for extremely fine processing. Note that a photomask is not required when exposure is performed by scanning an electron beam.

[0172] Dry etching, wet etching, and sandblasting methods can be used for etching thin films.

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

[0174] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0175] (Embodiment 5) This embodiment describes metal oxides (also called oxide semiconductors) that can be used in the OS transistor described in Embodiment 4 above.

[0176] The metal oxide used in the OS transistor preferably contains at least indium or zinc, and more preferably indium and zinc. For example, the metal oxide preferably contains indium, M (where 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] Furthermore, metal oxides can be formed by sputtering, chemical vapor deposition (CVD) methods such as metal-organic chemical vapor deposition (MOCVD), or atomic layer deposition (ALD).

[0178] In the following sections, we will describe oxides containing indium (In), gallium (Ga), and zinc (Zn) as examples of metal oxides. Note that oxides containing indium (In), gallium (Ga), and zinc (Zn) are sometimes called In-Ga-Zn oxides.

[0179] <Classification of crystal structures> Examples of crystalline structures for oxide semiconductors include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and polycrystal.

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

[0181] For example, in a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, in an In-Ga-Zn oxide film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical shape of the XRD spectrum peaks 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, the film or substrate cannot be said to be in an amorphous state.

[0182] Furthermore, the crystalline structure of a film or substrate can be evaluated by the diffraction pattern (also called the nano-beam electron diffraction pattern) observed using nano-beam 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. On the other hand, a spot-like pattern is observed in the diffraction pattern of an In-Ga-Zn oxide film deposited at room temperature, rather than a halo. Therefore, it is presumed that the In-Ga-Zn oxide deposited at room temperature is in an intermediate state, neither single-crystal nor polycrystalline, nor amorphous, and cannot be concluded to be in an amorphous state.

[0183] <<Oxide semiconductor structure>> It should be noted that oxide semiconductors may be classified differently from those described above when considering their structure. For example, oxide semiconductors can be divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the aforementioned CAAC-OS and nc-OS. Furthermore, non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS: amorphous-like oxide semiconductors), and amorphous oxide semiconductors.

[0184] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0185] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, the c-axis of which is oriented in a specific direction. This specific direction is the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region with periodic atomic arrangement. If we consider the atomic arrangement as a lattice arrangement, then a crystalline region is also a region with a aligned lattice arrangement. Furthermore, CAAC-OS has regions where multiple crystalline regions are connected in the ab-plane direction, and these regions may exhibit distortion. Distortion refers to a point in the connected region where the orientation of the lattice arrangement changes between a region with a aligned lattice arrangement and another region with a aligned lattice arrangement. In short, CAAC-OS is an oxide semiconductor that is c-axis oriented and does not exhibit clear orientation in the ab-plane direction.

[0186] Each of the above-mentioned 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 that crystalline region will be less than 10 nm. When a crystalline region is composed of many minute crystals, the size of that crystalline region may be around several tens of nanometers.

[0187] Furthermore, in In-Ga-Zn oxides, CAAC-OS tends to have a layered crystalline structure (also called a layered structure) consisting of layers containing indium (In) and oxygen (hereinafter referred to as the In layer) and layers containing gallium (Ga), zinc (Zn), and oxygen (hereinafter referred to as the (Ga,Zn) layer). Note that indium and gallium are mutually substitutable. Therefore, the (Ga,Zn) layer may contain indium. Also, the In layer may contain gallium. Also, the In layer may contain zinc. This layered structure can be observed, for example, as a lattice image in high-resolution TEM (Transmission Electron Microscope) images.

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

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

[0190] When the crystal region is observed from the specific direction described above, the lattice arrangement within that crystal region is based on a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the strain may have a pentagonal or heptagonal lattice arrangement. Moreover, in CAAC-OS, clear grain boundaries cannot be observed even near the strain. In other words, it can be seen that the formation of grain boundaries is suppressed by the strain in the lattice arrangement. This is thought to be because CAAC-OS can tolerate strain due to the non-dense arrangement of oxygen atoms in the ab-plane direction and the change in interatomic bond distances due to the substitution of metal atoms.

[0191] A crystal structure in which clear grain boundaries are observed is called a polycrystal. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in the transistor's on-current and field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries are not observed, is one of the crystalline oxides with a suitable crystal structure for the semiconductor layer of a transistor. In addition, a structure containing Zn is preferred for the composition of CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are preferred because they suppress the generation of grain boundaries more effectively than In oxide.

[0192] CAAC-OS is an oxide semiconductor with high crystallinity and no clearly defined grain boundaries. Therefore, CAAC-OS is less susceptible to the decrease in electron mobility caused by grain boundaries. Furthermore, since the crystallinity of oxide semiconductors can decrease due to the inclusion of impurities and the generation of defects, CAAC-OS can be said to be an oxide semiconductor with few impurities and defects (oxygen vacancies). Consequently, oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat-resistant and highly reliable. In addition, CAAC-OS is stable even at high temperatures (so-called thermal budget) during the manufacturing process. Therefore, using CAAC-OS in OS transistors allows for greater flexibility in the manufacturing process.

[0193] [nc-OS] nc-OS exhibits periodicity in atomic arrangement in minute regions (e.g., regions between 1 nm and 10 nm, particularly between 1 nm and 3 nm). In other words, nc-OS contains minute crystals. These minute crystals are also called nanocrystals because their size is, for example, between 1 nm and 10 nm, particularly between 1 nm and 3 nm. Furthermore, nc-OS shows no regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Consequently, depending on the analytical method, nc-OS may be indistinguishable from a-like OS or amorphous oxide semiconductors. For example, when structural analysis of an nc-OS film is performed using an XRD instrument, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Also, when electron diffraction (also called limited-field electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of the nanocrystals (e.g., 50 nm or more), a diffraction pattern resembling a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystal (for example, 1 nm to 30 nm), an electron diffraction pattern may be obtained in which multiple spots are observed within a ring-shaped region centered on a direct spot.

[0194] [a-like OS] a-like OS is an oxide semiconductor having a structure between nc-OS and amorphous oxide semiconductors. a-like OS has porous or low-density regions. That is, a-like OS has lower crystallinity compared to nc-OS and CAAC-OS. Also, a-like OS has a higher hydrogen concentration in the film compared to nc-OS and CAAC-OS.

[0195] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

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

[0197] Furthermore, CAC-OS is a composite metal oxide having a mosaic-like structure formed by the separation of the material into a first region and a second region, with the first region distributed within the film (hereinafter also referred to as a cloud-like structure). In other words, 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 In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS of In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of the CAC-OS film. The second region is the region where [Ga] is greater than the [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is the region where [In] is greater than the [In] in the second region, and [Ga] is smaller than the [Ga] in the second region. The second region is the region where [Ga] is greater than the [Ga] in the first region, and [In] is smaller than the [In] in the first region.

[0199] Specifically, the first region described above is a region whose main components are indium oxide and indium zinc oxide. The second region described above is a region whose main components are gallium oxide and gallium zinc oxide. In other words, the first region can be rephrased as a region whose main component is In. The second region can be rephrased as a region whose main component is Ga.

[0200] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

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

[0202] CAC-OS can be formed by sputtering, for example, under conditions where the substrate is not intentionally heated. When forming CAC-OS by sputtering, one or more gases selected from inert gases (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. Furthermore, a lower ratio of the oxygen gas flow rate to the total deposition gas flow rate during film formation is preferable. For example, the ratio of the oxygen gas flow rate to the total deposition gas flow rate during film formation should be 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 In-Ga-Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) confirms that it has a structure in which regions mainly composed of In (first region) and regions mainly composed of Ga (second region) are unevenly distributed and mixed.

[0204] Here, the first region is a region with higher conductivity compared to the second region. In other words, the conductivity of the metal oxide is exhibited when carriers flow through the first region. Therefore, a high field-effect mobility (μ) can be achieved when the first region is distributed in a cloud-like manner within the metal oxide.

[0205] On the other hand, the second region has higher insulating properties compared to the first region. In other words, the distribution of the second region within the metal oxide can suppress leakage current.

[0206] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulation due to the second region work complementaryly to give CAC-OS a switching function (on / off function). In other words, CAC-OS has conductive function in part of the material, insulating function in part of the material, and semiconductor function as a whole. By separating the conductive function and the insulating function, both functions can be maximized. Therefore, by using CAC-OS in a transistor, a high on-current (I on ), high field-effect mobility (μ), and good switching operation can be achieved.

[0207] Furthermore, transistors using CAC-OS offer high reliability. Therefore, CAC-OS is ideal for various semiconductor devices, such as those found in display devices.

[0208] Oxide semiconductors can take on diverse structures, each possessing different properties. One embodiment of the present invention may include two or more of the following: amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0209] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0210] By using the above-mentioned oxide semiconductor in transistors, it is possible to realize transistors with high field-effect mobility. Furthermore, it is possible to realize highly reliable transistors.

[0211] It is preferable to use an oxide semiconductor with a low carrier concentration for the transistor. For example, the carrier concentration of an oxide semiconductor is 1 × 10⁻⁶. 17 cm -3 The following is preferably 1 × 10 15 cm -3 More preferably 1 × 10 13 cm -3 More preferably 1 × 10 11 cm -3 More preferably 1 × 10 10 cm -3 It is less than 1 × 10 -9 cm -3 This concludes the explanation. Furthermore, when lowering the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film should be lowered to reduce the defect level density. In this specification, a low impurity concentration and low defect level density are referred to as high-purity intrinsic or substantially high-purity intrinsic. Note that oxide semiconductors with low carrier concentrations are sometimes referred to as high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors.

[0212] Furthermore, oxide semiconductor films that are high-purity intrinsic or substantially high-purity intrinsic may have a low trap level density due to their low defect level density.

[0213] Furthermore, charges trapped in the trap levels of oxide semiconductors can take a long time to disappear, sometimes behaving like fixed charges. Therefore, transistors in which channel formation regions are formed in oxide semiconductors with a high trap level density may exhibit unstable electrical properties.

[0214] Therefore, reducing the impurity concentration in the oxide semiconductor is effective in 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 impurities in an oxide semiconductor refer to elements other than the main components that make up the oxide semiconductor. For example, elements with a concentration of less than 0.1 atomic percent can be considered impurities.

[0215] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0216] In oxide semiconductors, the presence of silicon or carbon, which are Group 14 elements, leads to the formation of defect levels 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 compared by 2 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 17 atoms / cm 3 The following applies:

[0217] Furthermore, if an oxide semiconductor contains alkali metals or alkaline earth metals, it may form defect levels and generate carriers. Therefore, transistors using oxide semiconductors containing alkali metals or alkaline earth metals tend to exhibit normally-on characteristics. For this reason, the concentration of alkali metals or alkaline earth metals in the oxide semiconductor obtained by SIMS should be set to 1 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 16 atoms / cm 3 Do the following:

[0218] Furthermore, in oxide semiconductors, the presence of nitrogen generates electrons, which act as carriers, increasing the carrier concentration and making it easier for the semiconductor to become n-type. As a result, transistors using oxide semiconductors containing nitrogen tend to exhibit normally-on characteristics. Alternatively, the presence of nitrogen in oxide semiconductors can lead to the formation of trap levels. As a result, the electrical properties of the transistor may become unstable. For this reason, the nitrogen concentration in oxide semiconductors obtained by SIMS should be set to 5 × 10⁻⁶. 19 atoms / cm 3 Less than 5 × 10 18 atoms / cm 3More preferably 1 × 10 18 atoms / cm 3 More preferably 5 × 10 17 atoms / cm 3 Do the following:

[0219] Furthermore, hydrogen contained in oxide semiconductors can react with oxygen bonded to metal atoms to form water, potentially creating oxygen vacancies. Hydrogen can then fill these vacancies, generating electrons as carriers. Additionally, some of the hydrogen can combine with oxygen bonded to metal atoms to generate electrons. Therefore, transistors using oxide semiconductors containing hydrogen tend to exhibit normally-on characteristics. For this reason, it is preferable to reduce the hydrogen content in oxide semiconductors as much as possible. Specifically, the hydrogen concentration in the oxide semiconductor obtained by SIMS should be 1 × 10⁻⁶. 20 atoms / cm 3 Less than 1 × 10 19 atoms / cm 3 Less than 5x10 18 atoms / cm 3 Less than 1 × 10 18 atoms / cm 3 Make it less than.

[0220] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be provided.

[0221] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0222] (Embodiment 6) This embodiment describes an example of a transistor configuration that can be applied to a display device according to one aspect of the present invention. In particular, it describes a case in which a transistor is used in which silicon is included in the semiconductor layer in which the channel is formed.

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

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

[0225] By using silicon-based transistors, such as LTPS transistors, circuits that need to be driven at high frequencies (e.g., source driver circuits) can be fabricated on the same board as the display unit. This simplifies the external circuits implemented in the display device, reducing component and mounting costs.

[0226] Furthermore, it is preferable to use a transistor (hereinafter also called an OS transistor) in which a metal oxide (hereinafter also called an oxide semiconductor) is used in the semiconductor layer where the channel is formed, as at least one of the transistors included in the pixel circuit. OS transistors have extremely high field-effect mobility compared to transistors using amorphous silicon. In addition, OS transistors have a remarkably small source-drain leakage current (hereinafter also called an off-current) in the off state, making it possible to retain the charge accumulated in a capacitive element connected in series with the transistor for a long period of time. Moreover, by applying OS transistors, the power consumption of the display device can be reduced.

[0227] By using LTPS transistors for some of the transistors in the pixel circuit and OS transistors for others, a display device with low power consumption and high driving capability can be realized. A more preferable example is to apply OS transistors to transistors that function as switches to control conduction and non-conductivity between wiring, and LTPS transistors to transistors that control current.

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

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

[0230] Below, we will explain more specific configuration examples with reference to the drawings.

[0231] [Example of a display device configuration] Figure 18A shows a block diagram of the display device 610. The display device 610 includes a display unit 611, a drive circuit unit 612, and a drive circuit unit 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] Pixel 630 is electrically connected to wiring GL, wiring SLR, wiring SLG, and wiring SLB. Wiring SLR, wiring SLG, and wiring SLB are each electrically connected to the drive circuit unit 612. Wiring GL is electrically connected to the drive circuit unit 613. Drive circuit unit 612 functions as a source line drive circuit (also called a source driver), and drive circuit unit 613 functions as a gate line drive circuit (also called a gate driver). Wiring GL functions as a gate line, and wiring SLR, wiring SLG, and wiring SLB each function as source lines.

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

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

[0236] [Example of pixel circuit configuration] Figure 18B shows an example of a circuit diagram for a pixel 621 that can be applied to the sub-pixels 621R, 621G, and 621B. Pixel 621 includes transistors M1, M2, and M3, a capacitive element C1, and a light-emitting device LED. Wiring GL and wiring SL are electrically connected to pixel 621. Wiring SL corresponds to one of the wirings SLR, SLG, and SLB shown in Figure 18A.

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

[0238] A data potential D is applied to wiring SL. A selection signal is applied to wiring GL. This selection signal includes a potential that makes the transistor conduct and a potential that makes it non-conductive.

[0239] A reset potential is applied to wiring RL. An anode potential is applied to wiring AL. A cathode potential is applied to wiring CL. In pixel 621, the anode potential is set to a higher potential than the cathode potential. The reset potential applied to wiring RL can be set 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 set to a potential higher than the cathode potential, the same as the cathode potential, or lower than the cathode potential.

[0240] Transistors M1 and M3 function as switches. Transistor M2 functions as a transistor to control the current flowing to the light-emitting device LED. For example, it can be said that transistor M1 functions as a selector transistor and transistor M2 functions as a driver transistor.

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

[0242] Alternatively, OS transistors may be applied to all of transistors M1 through M3. In this case, one or more of the transistors in the drive circuit unit 612 and the drive circuit unit 613 may be LTPS transistors, and the other transistors may be OS transistors. For example, OS transistors may be applied to the transistors provided in the display unit 611, and LTPS transistors may be applied to the transistors provided in the drive circuit unit 612 and the drive circuit unit 613.

[0243] As an OS transistor, a transistor using an oxide semiconductor in the semiconductor layer where the channel is formed can be used. The semiconductor layer preferably contains, for example, indium, M (where 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, it is preferable that M is one or more selected from aluminum, gallium, yttrium, and tin. In particular, it is preferable to use an oxide containing indium, gallium, and zinc (also written as IGZO) as the semiconductor layer of the OS transistor. Alternatively, it is preferable to use an oxide containing indium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc.

[0244] Transistors using oxide semiconductors, which have a wider bandgap and lower carrier density than silicon, can achieve extremely low off-currents. Therefore, this low off-current allows the charge accumulated in a capacitive element connected in series with the transistor to be retained for extended periods. For this reason, it is preferable to use transistors made of oxide semiconductors for transistors M1 and M3, which are connected in series with the capacitive element C1. By using transistors with oxide semiconductors as transistors M1 and M3, it is possible to prevent the charge held in the capacitive element C1 from leaking through transistor M1 or M3. Furthermore, because the charge held in the capacitive element C1 can be retained for extended periods, it becomes possible to display still images for extended periods without rewriting the data in pixel 621.

[0245] Note that in Figure 18B, the transistor is shown as an n-channel type transistor, but a p-channel type transistor can also be used.

[0246] Furthermore, it is preferable that each transistor in the pixel 621 be formed in a row on the same substrate.

[0247] As the transistor in pixel 621, a transistor having a pair of gates that overlap across a semiconductor layer can be applied.

[0248] In a transistor having a pair of gates, configuring the pair of gates to be electrically connected to each other and given the same potential offers advantages such as increased on-current and improved saturation characteristics. Alternatively, one of the pair of gates may be given a potential that controls the transistor's threshold voltage. Furthermore, providing a constant potential to one of the pair of gates can improve the stability of the transistor's electrical characteristics. For example, one of the transistor's gates may be electrically connected to a wiring to which a constant potential is provided, or it may be electrically connected to its own source or drain.

[0249] The pixel 621 shown in Figure 18C is an example where transistors M1 and M3 each have a pair of gates. The pair of gates of transistors M1 and M3 are electrically connected. This configuration shortens the data writing time to the pixel 621.

[0250] Pixel 621, shown in Figure 18D, is an example in which a transistor with a pair of gates is applied to transistor M2, in addition to transistors M1 and M3. In transistor M2, the pair of gates are electrically connected. By applying such a transistor to transistor M2, the saturation characteristics are improved, making it easier to control the luminescence brightness of the light-emitting device LED and improving the display quality.

[0251] [Example of transistor configuration] The following describes examples of transistor cross-sectional configurations that can be applied to the above-mentioned display device.

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

[0253] The transistor 410 is provided over a substrate 401 and is a transistor in which polycrystalline silicon is used for a semiconductor layer. For example, the transistor 410 corresponds to the transistor M2 of a pixel 621. That is, FIG. 19A shows an example in which one of a source and a drain of the transistor 410 is electrically connected to a conductive layer 431 of a 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 contains silicon. The semiconductor layer 411 preferably contains 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 may also be configured to contain a metal oxide exhibiting semiconductor characteristics (also referred to as an oxide semiconductor). In this case, the transistor 410 can be referred to as 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-described impurities may be added to the channel formation region 411i.

[0257] An insulating layer 421 is provided over the substrate 401. The semiconductor layer 411 is provided over the insulating layer 421. The insulating layer 412 is provided to cover the semiconductor layer 411 and the insulating layer 421. The conductive layer 413 is provided on the insulating layer 412 at a position overlapping with the semiconductor layer 411.

[0258] Further, an insulating layer 422 is provided so as to cover the conductive layer 413 and the insulating layer 412. A conductive layer 414a and a conductive layer 414b are provided on 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 a source electrode and a drain electrode, and a part of the conductive layer 414b functions as the other of the source electrode and the drain electrode. Further, an insulating layer 423 is provided so as 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 on the insulating layer 423. The conductive layer 431 is provided on the insulating layer 423, and is electrically connected to the conductive layer 414b through 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] [Configuration Example 2] FIG. 19B shows a transistor 410a having a pair of gate electrodes. The transistor 410a shown in FIG. 19B mainly differs from that shown in FIG. 19A in that it includes a conductive layer 415 and an insulating layer 416.

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

[0262] In the transistor 410a shown in FIG. 19B, a part of the conductive layer 413 functions as a first gate electrode, and a part of the conductive layer 415 functions as a second gate electrode. At this time, a part of the insulating layer 412 functions as a first gate insulating layer, and a part of the insulating layer 416 functions as a second gate insulating layer.

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

[0264] When LTPS transistors are applied to all transistors constituting pixel 621, transistor 410 as exemplified in Figure 19A, or transistor 410a as exemplified in Figure 19B, can be applied. In this case, transistor 410a may be used for all transistors constituting pixel 621, transistor 410 may be applied to all transistors, or transistor 410a and transistor 410 may be used in combination.

[0265] [Configuration Example 3] The following describes an example of a configuration that includes both transistors with silicon semiconductor layers and transistors with metal oxide semiconductor layers.

[0266] Figure 19C shows a schematic cross-sectional view including transistors 410a and 450.

[0267] For transistor 410a, the above configuration example 1 can be used. Although an example using transistor 410a is shown here, a configuration with transistor 410 and transistor 450 is also possible, or a configuration with all of transistors 410, 410a, and 450 is also possible.

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

[0269] Figure 19C also shows an example where transistor 450 has a pair of gates.

[0270] The transistor 450 has a conductive layer 455, an insulating layer 422, a semiconductor layer 451, and an insulating layer 452 and a conductive layer 453. A portion of the conductive layer 453 functions as the first gate of the transistor 450, and a portion of the conductive layer 455 functions as the second gate of the transistor 450. At this time, a portion of the insulating layer 452 functions as the first gate insulating layer of the transistor 450, and a portion of the insulating layer 422 functions as the second gate insulating layer of the transistor 450.

[0271] The conductive layer 455 is provided on the insulating layer 412. The insulating layer 422 covers the conductive layer 455. The semiconductor layer 451 is provided on the insulating layer 422. The insulating layer 452 covers the semiconductor layer 451 and the insulating layer 422. The conductive layer 453 is provided on the insulating layer 452 and has a region that overlaps with the semiconductor layer 451 and the conductive layer 455.

[0272] Furthermore, an insulating layer 426 is provided covering the insulating layer 452 and the conductive layer 453. Conductive layers 454a and 454b are provided on the insulating layer 426. Conductive layers 454a and 454b are electrically connected to the semiconductor layer 451 at openings provided in the insulating layer 426 and the insulating layer 452. A portion of the conductive layer 454a functions as one of the source electrode and drain electrode, and a portion of the conductive layer 454b functions as the other of the source electrode and drain electrode. In addition, an insulating layer 423 is provided covering the conductive layer 454a, the conductive layer 454b, and the insulating layer 426.

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

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

[0275] In Figure 19C, the insulating layer 452, which functions as the first gate insulating layer of the transistor 450, is configured to cover the edge of the semiconductor layer 451. However, as shown in Figure 19D, the insulating layer 452 may be processed so that its upper surface shape matches or is approximately the same as that of the conductive layer 453.

[0276] In this specification, "approximately matching top surface shapes" means that at least a portion of the contours overlap between stacked layers. For example, this includes cases where the upper and lower layers are processed with the same mask pattern, or partially with the same mask pattern. However, strictly speaking, the contours may not overlap, and the upper layer may be located inside the lower layer, or the upper layer may be located outside the lower layer; in this case, too, it is said that the "top surface shapes are approximately matching."

[0277] Although an example is shown here in which transistor 410a corresponds to transistor M2 and is electrically connected to a pixel electrode, the present disclosure is not limited thereto. For example, transistor 450 or transistor 450a may have a configuration corresponding to transistor M2. In this case, transistor 410a corresponds to transistor M1, transistor M3, or another transistor.

[0278] This embodiment can be appropriately combined with other embodiments.

[0279] (Embodiment 7) This embodiment relates to a display device in which subpixels are arranged in a matrix and a light emitting element (light emitting diode chip) is provided for each subpixel.

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

[0281] In this specification, for example, two subpixels having the same coordinate representing a position in the row direction but coordinates representing a position in the column direction differing by 1 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. Further, two subpixels having the same coordinate representing a position in the column direction but coordinates representing a position in the row direction differing by 1 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. The same expression is used for elements other than subpixels as long as they are provided in a matrix. For example, when dividing a plurality of subpixels emitting light of the same color into four, it is only necessary to divide the row direction into two and the column direction into two.

[0282] [Configuration Example of Display Device] FIG. 20 is a top view showing a configuration example of a pixel 103 of a display device, which is a display device according to one aspect of the present invention.

[0283] The pixel 103 shown in Figure 20 is composed of four subpixels: subpixels 110a, 110b, 110c, and 110d. Each of the subpixels 110a, 110b, 110c, and 110d has a light-emitting element that emits light of a different color. Examples of subpixels 110a, 110b, and 110c include red (R), green (G), blue (B), and white (W). The subpixel 110a shown in Figure 20 can be associated with one of the LED chips, resulting in an LED chip with two terminals. Alternatively, to reduce the effort required for mounting, multiple subpixels can be provided on a single chip. For example, one chip can have three subpixels (red (R), green (G), and blue (B)) and have four terminals. Figure 20 shows an example where a single chip is composed of four subpixels of different colors enclosed in squares, arranged in a matrix. When composed of four subpixels, there are five terminals. Also, while Figure 20 shows the area of ​​each subpixel as being the same, this is not a limitation; for example, when using three subpixels, the green subpixel may have a larger area.

[0284] In this specification, for example, matters common to sub-pixels 110a, 110b, 110c, and 110d may be described. For other components distinguished by letters, when describing matters common to them, the letters may be omitted and symbols used.

[0285] Figure 20 shows the subpixels from row 1, column 1 to row 6, column 6.

[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 and Y directions intersect, for example, perpendicularly.

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

[0288] (Embodiment 8) This embodiment describes an example of a display device according to one aspect of the present invention.

[0289] In the display device of this embodiment, a pixel can be configured to have multiple subpixels, each having a light-emitting device that emits a different color from the others. For example, a pixel can be configured to have three types of subpixels. Examples of these three subpixels include subpixels of three colors: red (R), green (G), and blue (B); and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). Alternatively, a pixel can be configured to have four types of subpixels. Examples of these four subpixels include subpixels of four colors: R, G, B, and white (W); and subpixels of four colors: R, G, B, and Y.

[0290] There are no particular limitations on the arrangement of subpixels, and various methods can be applied. Examples of subpixel arrangements include stripe arrangements, S-stripe arrangements, matrix arrangements, delta arrangements, Bayer arrangements, and pentile arrangements.

[0291] Furthermore, examples of the top surface shape of a subpixel include polygons represented by triangles, quadrilaterals (including rectangles and squares), and pentagons, as well as polygons with rounded corners, ellipses, or circles. The top surface shape of a subpixel as referred to here corresponds to the top surface shape of the light-emitting region of a light-emitting device.

[0292] In a display device having light-emitting and light-receiving devices in its pixels, the pixels have a light-receiving function, allowing for the detection of contact or proximity of an object while displaying an image. For example, not only can the display device display an image using all of its subpixels, but some subpixels can also emit light as a light source, while the remaining subpixels display an image.

[0293] The pixels shown in Figures 21A, 21B, and 21C have sub-pixels G, B, R, and PS.

[0294] The pixels shown in Figure 21A have a stripe array applied. The pixels shown in Figure 21B have a matrix array applied.

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

[0296] The pixels shown in Figure 21D have sub-pixels G, B, R, IR, and PS.

[0297] Figure 21D shows an example where a single pixel spans two rows. The upper row (first row) has three subpixels (subpixel G, subpixel B, and subpixel R), while the lower row (second row) has two subpixels (one subpixel PS and one subpixel IR).

[0298] Note that the layout of the subpixels is not limited to the configuration shown in Figures 21A to 21D.

[0299] Sub-pixel R has a light-emitting device that emits red light. Sub-pixel G has a light-emitting device that emits green light. Sub-pixel B has a light-emitting device that emits blue light. Sub-pixel IR has a light-emitting device that emits infrared light. Sub-pixel PS has a light-receiving device. The wavelength of light detected by sub-pixel PS is not particularly limited, but it is preferable that the light-receiving device of sub-pixel PS is sensitive to the light emitted by the light-emitting devices of sub-pixel R, sub-pixel G, sub-pixel B, or sub-pixel IR. For example, it is preferable to detect one or more of the wavelengths of blue, violet, blue-violet, green, yellow-green, yellow, orange, red, and infrared light.

[0300] The light-receiving area of ​​a sub-pixel PS is smaller than the light-emitting area of ​​other sub-pixels. A smaller light-receiving area results in a narrower imaging range, which helps suppress blurring in the image and improves resolution. Therefore, using sub-pixel PS enables high-definition or high-resolution imaging. For example, sub-pixel PS can be used to image fingerprints, palm prints, irises, pulse patterns (including vein and artery patterns), or faces for personal authentication.

[0301] Furthermore, the sub-pixel 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, it is preferable for the sub-pixel PS to detect infrared light. This 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. 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 can detect an 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. With this configuration, it becomes possible to operate the display device without the object directly touching it, in other words, it becomes possible to operate the display device without contact (touchless). With the above configuration, the risk of the display device becoming dirty or scratched can be reduced, or it becomes possible to operate the display device without the object directly touching any dirt (e.g., dust or viruses) attached to the display device.

[0303] Furthermore, non-contact sensor functions can also be referred to as hover sensor functions, hover-touch sensor functions, near-touch sensor functions, and touchless sensor functions. Similarly, touch sensor functions can also be referred to as direct-touch sensor functions.

[0304] Furthermore, a display device according to one aspect of the present invention can have a variable refresh rate. For example, power consumption can be reduced by adjusting the refresh rate according to the content displayed on the display device (for example, within a range of 0.01 Hz to 240 Hz). In addition, a drive that reduces the power consumption of the display device by driving with a reduced refresh rate may be called an idling stop (IDS) drive.

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

[0306] Furthermore, in order to perform high-resolution imaging, it is preferable that sub-pixels PS be provided on all pixels of the display device. On the other hand, when sub-pixels PS are used in a touch sensor or near-touch sensor, the accuracy required is not as high as when capturing fingerprints, so it is sufficient to provide them on only some of the pixels of the display device. The detection speed can be increased by making the number of sub-pixels PS on the display device less than the number of sub-pixels R.

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

[0308] The pixel circuit PIX1 shown in Figure 21E includes a light-receiving device PD, transistors M11, M12, M13, M14, and a capacitive 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 its anode electrically connected to wiring V1 and its cathode electrically connected to either the source or drain of transistor M11. Transistor M11 has its gate electrically connected to wiring TX and its other source or drain electrically connected to one electrode of capacitive element C2, one source or drain of transistor M12, and the gate of transistor M13. Transistor M12 has its gate electrically connected to wiring RES and its other source or drain electrically connected to wiring V2. Transistor M13 has its source or drain electrically connected to wiring V3 and its other source or drain electrically connected to either the source or drain of transistor M14. Transistor M14 has its gate electrically connected to wiring SE and its other source or drain electrically connected to wiring OUT1.

[0310] Constant potentials are supplied to wirings V1, V2, and V3, respectively. When the photodetector PD is driven with reverse bias, a potential higher than that of wiring V1 is supplied to wiring V2. Transistor M12 is controlled by a signal supplied to wiring RES and has the function of resetting the potential of the node connected to the gate of transistor M13 to the potential supplied to wiring V2. Transistor M11 is controlled by a signal supplied to wiring TX and has the function of controlling the timing at which the potential of the above node changes according to the current flowing through the photodetector PD. Transistor M13 functions as an amplifying transistor that provides an output according to the potential of the above node. Transistor M14 is controlled by a signal supplied to wiring SE and functions as a selection transistor for reading the output according to the potential of the above node with an external circuit connected to wiring OUT1.

[0311] The pixel circuit PIX2 shown in Figure 21F includes a light-emitting device LED, transistors M15, M16, M17, and a capacitive element C3. Here, an example using a light-emitting diode as the light-emitting device LED is shown. In particular, it is preferable to use a red light-emitting LED, a blue light-emitting LED, or a green light-emitting LED as the light-emitting device LED.

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

[0313] Constant potentials are supplied to wirings V4 and V5, respectively. This allows the anode side of the light-emitting device LED to be at a high potential, and the cathode side to be at a lower potential than the anode side. Transistor M15 is controlled by a signal supplied to wiring VG and functions as a selection transistor to control the selected state of the pixel circuit PIX2. Transistor M16 functions as a drive transistor that controls the current flowing to the light-emitting device LED according to the potential supplied to its gate. When transistor M15 is conducting, the potential supplied to wiring VS is supplied to the gate of transistor M16, and the luminescence brightness of the light-emitting device LED can be controlled according to that potential. Transistor M17 is controlled by a signal supplied to wiring MS and has the function of outputting the potential between transistor M16 and the light-emitting device LED to the outside via wiring OUT2.

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

[0315] Transistors using metal oxides, which have a wider bandgap and lower carrier density than silicon, can achieve extremely low off-currents. Therefore, this low off-current allows the charge accumulated in the capacitive element connected in series with the transistor to be retained for a long period of time. For this reason, it is preferable to use transistors with oxide semiconductors for transistors M11, M12, and M15, which are connected in series with the capacitive element C2 or C3. Similarly, using transistors with oxide semiconductors for other transistors can reduce manufacturing costs. However, the present invention is not limited to this. Transistors using silicon in the semiconductor layer (hereinafter also referred to as Si transistors) may also be used.

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

[0317] Furthermore, when the transistor operates in the saturation region, OS transistors exhibit smaller changes in source-drain current due to changes in gate-source voltage compared to Si transistors. Therefore, by using OS transistors as driving transistors in the pixel circuit, the current flowing between the source and drain can be precisely controlled by changes in gate-source voltage, allowing for precise control of the current flowing to the light-emitting device. This enables precise control of the light-emitting brightness (allowing for greater gradation in the pixel circuit).

[0318] Furthermore, in terms of the saturation characteristics of the current flowing when a transistor operates in the saturation region, OS transistors can supply a more stable constant current (saturation current) than Si transistors, even as the source-drain voltage gradually increases. Therefore, by using an OS transistor as a driving transistor, for example, even if there are variations in the current-voltage characteristics of the light-emitting device (LED), a stable constant current can be supplied to the light-emitting device. In other words, when operating in the saturation region, the source-drain current remains almost unchanged even when the source-drain voltage is increased, thus stabilizing the luminescence brightness of the light-emitting device.

[0319] As described above, by using OS transistors in the drive transistors included in the pixel circuit, it is possible to suppress black level floating, increase luminescence brightness, enable multi-gradation, and suppress variations in light-emitting devices. As a result, the display device including the pixel circuit can display clear and smooth images, and as a result, one or more of the following can be observed: image sharpness, image clarity, and a high contrast ratio. Furthermore, by configuring the drive transistors included in the pixel circuit to have an extremely low off-current, the black display performed by the display device can be a display with virtually no light leakage (true black display).

[0320] Furthermore, transistors M11 to M17 can also be transistors in which silicon is applied to the semiconductor layer where the channel is formed. In particular, using highly crystalline silicon, such as single-crystal silicon or polycrystalline silicon, is preferable because it can achieve high field-effect mobility, enabling faster operation.

[0321] Furthermore, a configuration may be used in which one or more of transistors M11 to M17 are made of oxide semiconductors (OS transistors), and the others are made of silicon (Si transistors). Note that the Si transistors may be low-temperature polysilicon (LTPS) transistors (hereinafter referred to as LTPS transistors). A configuration using a combination of OS transistors and LTPS transistors is sometimes called LTPO. By using LTPO, it is possible to use LTPS transistors with high mobility and OS transistors with low off-current, thereby providing a display panel with high display quality.

[0322] Note that in Figures 21E and 21F, transistors are shown as n-channel transistors, but p-channel transistors can also be used.

[0323] It is preferable that the transistors in pixel circuit PIX1 and pixel circuit PIX2 be formed side by side on the same substrate. In particular, it is preferable to configure the transistors in pixel circuit PIX1 and pixel circuit PIX2 to be mixed within a single region and arranged periodically.

[0324] Furthermore, it is preferable to provide one or more layers having either or both transistors and / or capacitive elements in a position that overlaps with the light-receiving device PD or light-emitting device LED. This reduces the effective area occupied by each pixel circuit, enabling the realization of a high-definition light-receiving or display unit.

[0325] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0326] (Embodiment 9) In this embodiment, an electronic device using a display device according to one aspect of the present invention will be described with reference to Figure 22.

[0327] This embodiment shows an example in which the display device shown in any one of Embodiments 1 to 4 is installed inside a vehicle.

[0328] Figure 22 is a diagram illustrating an example of the vehicle's configuration. Figure 22 shows the dashboard 151 located around the driver's seat, a display device 154 fixed in front of the driver's seat, a camera 155, an air vent 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 installed across the 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 from Embodiments 1 to 4. Figure 22 shows the display device 154 as a single display surface, illustrating an example in which a total of 18 light-emitting devices are combined in 2 rows and 9 columns. In Figure 22, the boundaries of the pixel areas are indicated by dotted lines, but the actual displayed image will not show dotted lines, and the configuration will be seamless or inconspicuous. Furthermore, the display device 154 may have a see-through structure with a translucent area that allows the outside to be seen.

[0330] The display device 154 is preferably equipped with a touch sensor or a non-contact proximity sensor. Alternatively, it is preferable that gesture operation using a separately provided camera is possible.

[0331] Figure 22 shows an autonomous vehicle without a steering wheel (also called a handle), but it is not limited to this, and a steering wheel may be provided, and a display device with a curved surface may be attached to the steering wheel. In that case, the configuration shown in Embodiment 2 can be used.

[0332] Furthermore, multiple cameras 155 for capturing the rear and side conditions may be installed outside the vehicle. Figure 22 shows an example where cameras 155 are installed instead of side mirrors, but both side mirrors and cameras may be installed. CCD cameras and CMOS cameras can be used as cameras 155. In addition to these cameras, infrared cameras may also be used in combination. Since the output level of infrared cameras increases with the temperature of the subject, they can detect or extract living organisms (people or animals).

[0333] Images captured by camera 155 can be output to display device 154. This display device 154 is primarily used to assist in driving the vehicle. Camera 155 captures the situation to the rear and sides with a wide field of view, and by displaying these images on the display device 154, the driver can see their blind spots, thereby preventing accidents.

[0334] Alternatively, a distance image sensor may be installed on the roof of the car, and the image obtained by the distance image sensor may be displayed on the display device 154. An image sensor or LiDAR (Light Detection and Ranging) can be used as the distance image sensor. By displaying both the image obtained by the image sensor and the image obtained by the distance image sensor on the display device 154, more information can be provided to the driver, assisting in driving.

[0335] Furthermore, a display device 152 having a curved surface can also be installed inside the roof of the car, i.e., in the ceiling portion. When a display device 152 having a curved surface is installed in the ceiling portion, the display device shown in Embodiment 1 or Embodiment 2 can be applied.

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

[0337] The images displayed on the display device 154 can be freely configured according to the driver's preference. For example, television images, DVD images, and web videos can be displayed in the left image area, map information can be displayed in the central image area, and measuring instruments such as speedometers and tachometers can be displayed in the right image area.

[0338] Furthermore, Figure 22 shows that display devices 159a and 159b are provided along the surfaces of the right door 158a and the left door 158b, respectively. Display devices 159a and 159b can each be formed using one or more light-emitting devices. For example, a single display surface can be formed using a 1x2 arrangement of light-emitting devices.

[0339] Display devices 159a and 159b are arranged facing each other.

[0340] Furthermore, it is 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, the vehicle can perform biometric authentication, such as fingerprint authentication or palm print authentication, by having the driver touch at least one image area of ​​the display devices 152, 154, 159a, or 159b. The vehicle may also have a function to adjust the environment to the driver's preferences once the driver has been 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 conditioning, setting the wiper speed (frequency), setting the audio volume, or reading the audio playlist.

[0342] Furthermore, if the driver is authenticated by biometric authentication, the vehicle can be automatically put into a drivable state, such as with the engine running or, in the case of an electric vehicle, ready to start, eliminating the need for a key, which is preferable.

[0343] While this explanation focuses on display devices surrounding the driver's seat, display devices can also be installed in the rear seats to surround the passengers.

[0344] Furthermore, we will explain using Figure 23 as another example.

[0345] Figure 23 is a diagram illustrating an example of the vehicle's configuration. Figure 23 shows the dashboard 852, steering wheel 841, windshield 854, camera 855, air vent 856, passenger-side door 858a, and driver-side door 858b, all located around the driver's and passenger's seats. The display unit 851 is located across the left and right sides of the dashboard 852.

[0346] The steering wheel 841 has a light-receiving unit 840. The light-receiving unit 840 has the function of emitting light and the function of capturing images. The light-receiving unit 840 can acquire biometric information, such as the driver's fingerprint, palm print, or vein pattern, and the driver can be authenticated based on this biometric information. Therefore, since the vehicle cannot be started by any driver other than those who have been pre-registered, an extremely high level of security can be achieved.

[0347] In addition, multiple cameras 855 for capturing the rear and side conditions may be installed outside the vehicle. Figure 23 shows an example where cameras 855 are installed instead of side mirrors, but both side mirrors and cameras may be installed. CCD cameras and CMOS cameras can be used as cameras 855. In addition to these cameras, infrared cameras may also be used in combination. Since the output level of infrared cameras increases with the temperature of the subject, they can detect or extract living organisms (people or animals).

[0348] Images captured by the camera 855 can be output to either the display unit 851 or the light-emitting / receiving unit 840, or both. This display unit 851 or light-emitting / receiving unit 840 is primarily used to assist in driving the vehicle. The camera 855 captures the situation to the rear and sides with a wide field of view, and by displaying these images on the display unit 851 or light-emitting / receiving unit 840, the driver's blind spots become visible, which can help prevent accidents.

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

[0350] Furthermore, Figure 23 shows that the display unit 851 is provided across the dashboard, center console, and left and right pillars. Figure 23 shows an example in which the display unit 851 is composed of eight display panels (display panels 880a to 880h), but 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 the position corresponding to the center console. Here, a combination of display panel 880d and a non-rectangular display panel 880c is shown. Although display panel 880d is rectangular, when display panel 880d and display panel 880c are combined as a single panel, the display panels 880d and 880c as a whole become a non-rectangular panel. Display panels 880e and 880f are provided on the rear side of the dashboard as seen 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 configured according to the driver's preference. For example, television, DVD, and web videos can be displayed on the right-hand display panels 880a and 880e, map information on the central display panel 880c, measuring instruments such as the speedometer and tachometer on the driver's side display panels 880b and 880f, and audio information on the display panel 880d between the driver and passenger seats. Furthermore, by displaying the external scenery in the driver's line of sight in real time on the display panels 880g and 880h located on the pillars, it is possible to create a pseudo-pillarless vehicle, reducing blind spots and thus achieving a safer vehicle.

[0352] Furthermore, Figure 23 shows that display units 859a and 859b are provided along the surfaces of the passenger-side door 858a and the driver-side door 858b, respectively. Each of the display units 859a and 859b can be formed using one or more display panels.

[0353] Display units 859a and 859b are positioned facing each other, and display unit 851 is provided on the dashboard 852 so as to connect the ends of display unit 859a and display unit 859b. As a result, the driver and the passenger in the front seat are surrounded on the front and both sides by display units 851, 859a, and 859b. For example, by displaying a continuous image on display units 859a, 851, and 859b, a high level of immersion can be provided to the driver or passenger.

[0354] Additionally, multiple cameras 855 for capturing the rear and side views may be installed outside the vehicle. Figure 23 shows an example where cameras 855 are installed instead of side mirrors, but both side mirrors and cameras may be installed.

[0355] Camera 855 can be a CCD camera or a CMOS camera. In addition to these cameras, an infrared camera may be used in combination. Since the output level of an infrared camera increases with the temperature of the subject, it can detect or extract living organisms (people or animals).

[0356] Images captured by camera 855 can be output to one or more of the display panels. Camera 855 can primarily assist in driving the vehicle using the images displayed on the display unit 851. For example, by using camera 855 to capture the situation to the rear and sides with a wide field of view and displaying those images on one or more of the display panels, the driver can see their blind spots, thereby preventing accidents.

[0357] Furthermore, the display units 859a and 859b can display images that are synthesized from images acquired by the camera 855 and synchronized with the view from the car window. In other words, the display units 859a and 859b can also display images that appear to be transparent to the driver and passengers through the doors 858a and 858b. This allows the driver and passengers to experience a sensation as if they are floating.

[0358] Furthermore, it is preferable that at least one of the display panels 880a to 880h be a display panel with an imaging function. Additionally, one or more of the display panels provided in the display units 859a and 859b may also be display panels with an imaging function.

[0359] As described above, by adopting the configuration of one aspect of the present invention, the degree of design freedom for the display device is increased, and the design of the display device can be improved. Furthermore, the display device according to one aspect of the present invention can be suitably used when mounted on a vehicle.

[0360] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

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

[0362] The electronic device of this embodiment has a display device according to one aspect of the present invention in its display unit. The display device according to one aspect of the present invention is easily made high-definition and high-resolution. Therefore, it can be used in the display units of various electronic devices.

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

[0364] In particular, a display device according to one aspect of the present invention can be used suitably in electronic devices having a relatively small display area because it can increase the resolution. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), head-mounted displays for VR, glasses-type devices for AR and MR, and wearable devices that can be worn on the head.

[0365] A display device according to one aspect of the present invention preferably has an extremely high resolution such as HD (1280 x 720 pixels), FHD (1920 x 1080 pixels), WQHD (2560 x 1440 pixels), WQXGA (2560 x 1600 pixels), 4K (3840 x 2160 pixels), or 8K (7680 x 4320 pixels). In particular, a resolution of 4K, 8K, or higher is preferred. Furthermore, the pixel density (resolution) of the display device according to one aspect of the present invention is preferably 100 ppi or more, preferably 300 ppi or more, more preferably 500 ppi or more, more preferably 1000 ppi or more, more preferably 2000 ppi or more, more preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 7000 ppi or more. By using a display device having either high resolution or high detail, or both, it becomes possible to further enhance the sense of presence and depth in portable or personal-use electronic devices for home use. Furthermore, there are no particular limitations on the aspect ratio of the display device according to one embodiment of the present invention. For example, the display device can support various aspect ratios (e.g., 1:1 (square), 4:3, 16:9, 16:10).

[0366] The electronic device of this embodiment may have sensors (including those with the function of measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation).

[0367] Figure 24A shows an example of a television system. The television system 7100 has a display unit 7000 incorporated into a housing 7101. Here, the housing 7101 is shown supported by a stand 7103.

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

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

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

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

[0372] Figure 24B shows a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 has a display unit 7000 that is provided along the curved surface of the column 7401.

[0373] In Figure 24B, a display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0374] The larger the display area 7000, the more information can be provided at once. Furthermore, a larger display area 7000 is more eye-catching, which can, for example, enhance the effectiveness of advertising.

[0375] Applying a touch panel to the display unit 7000 is preferable because it not only allows images or videos to be displayed on the display unit 7000, but also enables intuitive operation by the user. Furthermore, when used for purposes such as providing route information or traffic information, intuitive operation can enhance usability.

[0376] Furthermore, as shown in Figure 24B, it is preferable that the digital signage 7400 can be linked wirelessly with an information terminal 7411, which is a smartphone owned by the user. For example, the advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7411. Also, the display on the display unit 7000 can be switched by operating the information terminal 7411.

[0377] Furthermore, the digital signage 7400 can be used to run games using the screen of the information terminal 7411 as the control device (controller). This allows a large number of users to participate in and enjoy the game simultaneously.

[0378] This embodiment can be combined with other embodiments as appropriate. [Explanation of Symbols]

[0379] 10: Support, 11: Support, 12a: Third substrate, 12b: Fourth substrate, 12: Substrate, 13: Cover material, 14b: Light emission direction, 15: Region, 16a: Light emission panel, 16b: Light emission panel, 16c: Light emission panel, 16d: Light emission panel, 16e: Fifth light emission panel, 16f: Sixth light emission panel, 16g: Seventh light emission panel, 16h: Eighth light emission 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 vent, 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 455: Conductive layer, 610: Display device, 611: Display unit, 612: Drive circuit unit, 613: Drive circuit unit, 621B: Sub-pixel, 621G: Sub-pixel, 621R: Sub-pixel, 621: Pixel, 630: Pixel, 700A: Display device, 700: Laser irradiation line, 702: Pixel area, 704: Gate driver circuit unit, 706: Source driver circuit unit, 710: Signal line, 711: Wiring section, 732: Resin, 736: Coloring 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: Capacitive 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-receiving / light-receiving part, 841: Stearing 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: Grinding stone, 909: Grinding 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: Apparatus, 951: Stage, 953: Uniaxial robot, 955: Uniaxial robot, 957: Camera, 959: Gripping mechanism, 961: Control device, 963: Unit, 7000: Display unit, 7100: Television equipment, 7101: Housing, 7103: Stand, 7111: Remote control operator, 7400: Digital signage, 7401: Column, 7411: Information terminal,

Claims

1. A first substrate having a first nitride film, It comprises multiple flexible substrates on which multiple microLED chips are mounted, In a cross-sectional view, the plurality of flexible substrates are positioned so as to be sandwiched between the bent first substrates. A resin is provided between the first nitride film and the plurality of flexible substrates. The light emitted from the micro LED chip passes through the first substrate, which is used in electronic devices.

2. A first substrate on which a first nitride film is provided, A second substrate on which a second nitride film is provided, It comprises multiple flexible substrates on which multiple microLED chips are mounted, In a cross-sectional view, the plurality of flexible substrates are located between the first substrate and the second substrate. A resin is provided between the first nitride film and the plurality of flexible substrates. A resin is provided between the second nitride film and the plurality of flexible substrates. The light emitted from the micro LED chip passes through the first substrate, which is used in electronic devices.

3. A first substrate having a first nitride film, A flexible third substrate having multiple microLED chips and a first element layer, It has a flexible fourth substrate having multiple microLED chips and a second element layer, The first element layer has a first transistor, The aforementioned second element layer has a second transistor, The end face of the first element layer and the end face of the second element layer are adjacent to each other. The end face of the flexible third substrate and the end face of the flexible fourth substrate are adjacent to each other. In a cross-sectional view, the end face of the first element layer and the end face of the flexible third substrate do not coincide. In a cross-sectional view, the flexible third substrate and the flexible fourth substrate are positioned so as to be sandwiched between the bent first substrate. A resin is provided between the flexible third substrate and the flexible fourth substrate and the first nitride film. The light emitted from the micro LED chip passes through the first substrate, which is used in electronic devices.

4. A first substrate on which a first nitride film is provided, A second substrate on which a second nitride film is provided, A flexible third substrate having multiple microLED chips and a first element layer, It has a flexible fourth substrate having multiple microLED chips and a second element layer, The first element layer has a first transistor, The aforementioned second element layer has a second transistor, The end face of the first element layer and the end face of the second element layer are adjacent to each other. The end face of the flexible third substrate and the end face of the flexible fourth substrate are adjacent to each other. In a cross-sectional view, the end face of the first element layer and the end face of the flexible third substrate do not coincide. In a cross-sectional view, the flexible third substrate and the flexible fourth substrate are located between the first substrate and the second substrate. A resin is provided between the flexible third substrate and the flexible fourth substrate and the first nitride film. A resin is provided between the flexible third substrate and the flexible fourth substrate and the second nitride film. The light emitted from the micro LED chip passes through the first substrate, which is used in electronic devices.

5. In any one of claims 1 to 4, The first substrate is a light-transmitting electronic device.

6. In any one of claims 1 to 4, The aforementioned resin is translucent, and the electronic device is also translucent.

Images