Method for manufacturing a display device

Abstract

Provided is a display device that has a high definition or a high resolution. The display device is fabricated by a method comprising: forming a conductive film, a first layer, and a first sacrificial layer; processing the first layer and the first sacrificial layer to expose a part of the conductive film; forming a second layer and a second sacrificial on the first sacrificial layer and the conductive film; processing the second layer and the second sacrificial layer to expose a part of the conductive film; processing the conductive film to form a first pixel electrode overlapping the first sacrificial layer and a second pixel electrode overlapping the second sacrificial layer; forming a two-layer insulating film covering at least the side surfaces of the first pixel electrode, second pixel electrode, first layer, and second layer, the side surface and upper surface of the first sacrificial layer, and the side surface and the upper surface of the second sacrificial layer; processing the two-layer insulating film to form a side wall covering the side surfaces of at least the first pixel layer and the first layer; and removing the first sacrificial layer and the second sacrificial layer to form a common electrode on the first layer and second layer.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a display device, a display module, and electronic equipment. Another aspect of the present invention relates to a method 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 include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), methods for driving them, or methods for manufacturing them. [Background technology]

[0003] In recent years, display devices have been expected to have applications in a variety of uses. For example, large-scale display devices are used in home television systems (also called televisions or television receivers), digital signage, and PID (Public Information Display). Furthermore, development is progressing on mobile information terminals such as smartphones and tablet devices equipped with touch panels.

[0004] Furthermore, there is a demand for higher resolution display devices. Devices requiring high-resolution displays, such as those for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR), are being actively developed.

[0005] As a display device, for example, a light-emitting device (also referred to as a light-emitting element) having a light-emitting device has been developed. A light-emitting device (also referred to as an EL device or an EL element) that utilizes the electroluminescence (hereinafter referred to as EL) phenomenon has characteristics such as being easily thinned and lightened, being able to respond quickly to an input signal, and being able to be driven using a DC constant voltage power supply, and is applied to display devices.

[0006] Patent Document 1 discloses a display device for VR using an organic EL device (also referred to as an organic EL element).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] When manufacturing a display device having a plurality of organic EL devices with different emission colors, it is necessary to form the emission layers with different emission colors in an island shape.

[0009] For example, an island-shaped emission layer can be formed by a vacuum evaporation method using a metal mask (also referred to as a shadow mask). However, in this method, due to various influences such as the accuracy of the metal mask, the misalignment between the metal mask and the substrate, the deflection of the metal mask, and the scattering of the vapor, which causes the spread of the outline of the formed film, a deviation from the design occurs in the shape and position of the island-shaped emission layer, making it difficult to increase the definition and aperture ratio of the display device. Also, during evaporation, the outline of the layer may become blurred and the thickness at the edge may become thin. That is, the thickness of the island-shaped emission layer may vary depending on the location. In addition, when manufacturing a large, high-resolution, or high-definition display device, there is a concern that the low dimensional accuracy of the metal mask and deformation due to heat or the like may result in a low manufacturing yield.

[0010] Also, when manufacturing a display device using a vacuum evaporation method with a metal mask, it is necessary to periodically clean the metal mask, and the process stops during cleaning. Therefore, it is desirable to prepare at least two or more manufacturing apparatuses and manufacture using one manufacturing apparatus while the other manufacturing apparatus is under maintenance. Considering mass production, a plurality of lines of manufacturing apparatuses are required. Thus, there is a problem that the initial investment for introducing the manufacturing apparatuses becomes extremely large.

[0011] One aspect of the present invention is to provide a high-definition display device as one of the problems. One aspect of the present invention is to provide a high-resolution display device as one of the problems. One aspect of the present invention is to provide a large-sized display device as one of the problems. One aspect of the present invention is to provide a small-sized display device as one of the problems. One aspect of the present invention is to provide a highly reliable display device as one of the problems.

[0012] One aspect of the present invention is to provide a method for manufacturing a high-definition display device as one of the problems. One aspect of the present invention is to provide a method for manufacturing a high-resolution display device as one of the problems. One aspect of the present invention is to provide a method for manufacturing a large-sized display device as one of the problems. One aspect of the present invention is to provide a method for manufacturing a small-sized display device as one of the problems. One aspect of the present invention is to provide a method for manufacturing a highly reliable display device as one of the problems. One aspect of the present invention is to provide a method for manufacturing a display device with a high yield as one of the problems.

[0013] Note that the description of these problems does not prevent the existence of other problems. One aspect of the present invention does not necessarily need to solve all of these problems. It is possible to extract other problems from the description of the specification, drawings, and claims.

Means for Solving the Problems

[0014] One aspect of the present invention involves forming an insulating layer, forming a conductive film on the insulating layer, forming a first layer on the conductive film, forming a first sacrificial layer on the first layer, processing the first layer and the first sacrificial layer to expose a portion of the conductive film, forming a second layer on the first sacrificial layer and the conductive film, forming a second sacrificial layer on the second layer, processing the second layer and the second sacrificial layer to expose a portion of the conductive film, and processing the conductive film to form a first pixel electrode overlapping the first sacrificial layer and a second pixel electrode overlapping the second sacrificial layer, and at least the first pixel electrode This is a method for manufacturing a display device, comprising: forming a first insulating film covering the sides, the sides of the second pixel electrode, the sides of the first layer, the sides of the second layer, the sides and top of the first sacrificial layer, and the sides and top of the second sacrificial layer; forming a second insulating film on the first insulating film; processing the first insulating film and the second insulating film to form a first side wall covering at least the sides of the first pixel electrode and the sides of the first layer, a second side wall on the first side wall; removing the first and second sacrificial layers; and forming a common electrode on the first layer and the second layer.

[0015] Preferably, a first sacrificial film and a second sacrificial film are formed as the first sacrificial layer, a first resist mask is formed on the second sacrificial film, the second sacrificial film is processed using the first resist mask, the first resist mask is removed, the processed second sacrificial film is used as a hard mask to process the first sacrificial film, and the processed first sacrificial film is used as a hard mask to process the first layer.

[0016] It is preferable to process the conductive film using the first sacrificial layer and the second sacrificial layer as a hard mask.

[0017] The first layer may include a first light-emitting unit, a charge-generating layer on the first light-emitting unit, and a second light-emitting unit on the charge-generating layer. The first light-emitting unit and the second light-emitting unit may have light-emitting layers that emit light of the same color.

[0018] After removing the first and second sacrificial layers, a third layer may be formed on the first and second layers, and a common electrode may be formed on the third layer.

[0019] In the processing step of the conductive film, recesses may be formed in the insulating layer.

[0020] One aspect of the present invention is a display device comprising a first light-emitting device, a second light-emitting device, a first sidewall, and a second sidewall, wherein the first light-emitting device comprises a first pixel electrode, a first light-emitting layer on the first pixel electrode, and a common electrode on the first light-emitting layer, and the second light-emitting device comprises a second pixel electrode, a second light-emitting layer on the second pixel electrode, and a common electrode on the second light-emitting layer, the first light-emitting device and the second light-emitting device have the function of emitting light of different colors from each other, the first sidewall covers at least the side surface of the first pixel electrode and the side surface of the first light-emitting layer, and the second sidewall overlaps at least the side surface of the first pixel electrode and the side surface of the first light-emitting layer via the first sidewall.

[0021] The first light-emitting device may have a configuration comprising a first hole injection layer on a first pixel electrode, a first hole transport layer on the first hole injection layer, and a first electron transport layer on the first light-emitting layer, each with sides covered by a first side wall, and further comprising an electron injection layer on the first electron transport layer. Alternatively, the first light-emitting device may have a configuration comprising a first hole injection layer on a first pixel electrode, a first hole transport layer on the first hole injection layer, a first electron transport layer on the first light-emitting layer, and a first electron injection layer on the first electron transport layer, each with sides covered by a first side wall.

[0022] One aspect of the present invention comprises a first light-emitting device, a second light-emitting device, a first sidewall, and a second sidewall, wherein the first light-emitting device comprises a first pixel electrode, a first light-emitting unit on the first pixel electrode, a first charge generation layer on the first light-emitting unit, a second light-emitting unit on the first charge generation layer, and a common electrode on the second light-emitting unit, and the second light-emitting device comprises a second pixel electrode, a third light-emitting unit on the second pixel electrode, and a third light-emitting unit The display device comprises a second charge generation layer on a plate, a fourth light-emitting unit on the second charge generation layer, and a common electrode on the fourth light-emitting unit, wherein the first light-emitting device and the second light-emitting device have the function of emitting light of different colors from each other, the first side wall covers at least the side surface of the first pixel electrode and the side surface of the first charge generation layer, and the second side wall overlaps at least the side surface of the first pixel electrode and the side surface of the first charge generation layer via the first side wall.

[0023] Preferably, the first and second light-emitting units each emit light of a first color, and the third and fourth light-emitting units each emit light of a second color.

[0024] One aspect of the present invention comprises a first light-emitting device, a second light-emitting device, a third light-emitting device, a first side wall, and a second side wall, wherein the first light-emitting device comprises a first pixel electrode, a first light-emitting unit on the first pixel electrode, a first charge generation layer on the first light-emitting unit, a second light-emitting unit on the first charge generation layer, and a common electrode on the second light-emitting unit, and the second light-emitting device comprises a second pixel electrode, a third light-emitting unit on the second pixel electrode, a second charge generation layer on the third light-emitting unit, a fourth light-emitting unit on the second charge generation layer, and a common electrode on the fourth light-emitting unit. The third light-emitting device comprises a third pixel electrode, a fifth light-emitting unit on the third pixel electrode, a third charge generation layer on the fifth light-emitting unit, a sixth light-emitting unit on the third charge generation layer, and a common electrode on the sixth light-emitting unit. The first light-emitting device, the second light-emitting device, and the third light-emitting device each have the function of emitting light of different colors. The first sidewall covers at least the side surface of the first pixel electrode and the side surface of the first charge generation layer, and the second sidewall overlaps at least the side surface of the first pixel electrode and the side surface of the first charge generation layer via the first sidewall.

[0025] Preferably, the first and second light-emitting units each emit light of a first color, the third and fourth light-emitting units each emit light of a second color, and the fifth and sixth light-emitting units each emit light of a third color. Preferably, the first color is red, the second color is green, and the third color is blue.

[0026] It is preferable to have a protective layer on the common electrode.

[0027] The first light-emitting device and the second light-emitting device may be provided on an insulating layer having a recess.

[0028] There may be an air gap between the first light-emitting device and the second light-emitting device.

[0029] One aspect of the present invention is a display module having a display device with any of the above configurations, to which a connector such as a Flexible Printed Circuit (FPC) or TCP (Tape Carrier Package) is attached, or a display module on which an integrated circuit (IC) is mounted by a COG (Chip On Glass) method or a COF (Chip On Film) method, etc.

[0030] One aspect of the present invention is an electronic device having the above-mentioned display module and at least one of a housing, a battery, a camera, a speaker, and a microphone. [Effects of the Invention]

[0031] According to one aspect of the present invention, a high-definition display device can be provided. According to one aspect of the present invention, a high-resolution display device can be provided. According to one aspect of the present invention, a large-scale display device can be provided. According to one aspect of the present invention, a small-scale display device can be provided. According to one aspect of the present invention, a highly reliable display device can be provided.

[0032] According to one aspect of the present invention, a method for manufacturing a high-definition display device can be provided. According to one aspect of the present invention, a method for manufacturing a high-resolution display device can be provided. According to one aspect of the present invention, a method for manufacturing a large display device can be provided. According to one aspect of the present invention, a method for manufacturing a small display device can be provided. According to one aspect of the present invention, a method for manufacturing a highly reliable display device can be provided. According to one aspect of the present invention, a method for manufacturing a display device with a high yield can be provided.

[0033] Furthermore, the description of these effects does not preclude the existence of other effects. One aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description, drawings, and claims. [Brief explanation of the drawing]

[0034] Figure 1A is a top view showing an example of a display device. Figure 1B is a cross-sectional view showing an example of a display device. Figure 2A is a top view showing an example of a display device. Figure 2B is a cross-sectional view showing an example of a display device. Figures 3A to 3F are top views showing an example of a pixel. Figures 4A to 4F are top views showing an example of a pixel. Figures 5A to 5G are top views showing an example of a pixel. Figures 6A to 6D are top views showing an example of a pixel. Figures 7A to 7D are top views showing an example of a pixel. Figures 7E to 7G are cross-sectional views showing an example of a display device. Figures 8A to 8C are top views showing an example of a method for manufacturing a display device. Figures 9A to 9C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 10A to 10C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 11A to 11C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 12A to 12C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 13A to 13C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 14A to 14E are cross-sectional views showing an example of a method for manufacturing a display device. Figures 15A to 15C are cross-sectional views showing an example of a display device. Figures 16A and 16B are cross-sectional views showing an example of a display device. Figures 17A and 17B are cross-sectional views showing an example of a display device. Figures 18A and 18B are cross-sectional views showing an example of a display device. Figure 19 is a perspective view showing an example of a display device. Figure 20A is a cross-sectional view showing an example of a display device. Figures 20B and 20C are cross-sectional views showing an example of a transistor. Figure 21 is a cross-sectional view showing an example of a display device. Figures 22A and 22B are perspective views showing an example of a display module. Figure 23 is a cross-sectional view showing an example of a display device. Figure 24 is a cross-sectional view showing an example of a display device. Figure 25 is a cross-sectional view showing an example of a display device. Figure 26A is a block diagram showing an example of a display device. Figures 26B to 26D show examples of pixel circuits. Figures 27A to 27D show examples of transistors. Figures 28A and 28B show examples of electronic devices. Figures 29A and 29B show examples of electronic devices. Figures 30A and 30B show examples of electronic devices. Figures 31A to 31D show examples of electronic devices. Figures 32A to 32G show examples of electronic devices. [Modes for carrying out the invention]

[0035] Embodiments will be described in detail 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 that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be construed as being limited to the descriptions of the embodiments shown below.

[0036] In the invention described below, the same reference numerals are used in common across different drawings for identical parts or parts having similar functions, and repeated explanations are omitted. Furthermore, when referring to similar functions, the same hatching pattern may be used, and reference numerals may not be assigned.

[0037] Furthermore, the position, size, and scope of each component shown in the drawings may not represent the actual position, size, and scope for the sake of ease of understanding. Therefore, the disclosed invention is not necessarily limited to the position, size, and scope disclosed in the drawings.

[0038] It should be noted that the terms "film" and "layer" can be interchanged depending on the context or situation. For example, the term "conductive layer" can be changed to "conductive film." Or, for example, the term "insulating film" can be changed to "insulating layer."

[0039] (Embodiment 1) In this embodiment, a display device according to one aspect of the present invention and a method for manufacturing the same will be explained with reference to Figures 1 to 14.

[0040] In a method for manufacturing a display device according to one aspect of the present invention, a conductive film is formed to create a first layer (which can be described as an EL layer or a part of an EL layer) containing a light-emitting layer that emits light of a first color, and then a first sacrificial layer is formed on the first layer. A first resist mask is then formed on the first sacrificial layer, and the first layer and the first sacrificial layer are processed using the first resist mask to form an island-shaped first layer. Subsequently, a second layer (which can be described as an EL layer or a part of an EL layer) containing a light-emitting layer that emits light of a second color is formed in an island shape using a second sacrificial layer and a second resist mask, similar to the first layer.

[0041] Thus, in the method for manufacturing a display device according to one aspect of the present invention, the island-shaped EL layer is not formed using a metal mask with a fine pattern, but rather formed by processing after the EL layer has been deposited on one surface. Therefore, it is possible to realize a high-definition display device or a display device with a high aperture ratio, which has been difficult to achieve until now. Furthermore, since the EL layer can be manufactured separately for each color, it is possible to realize a display device that is extremely vivid, has high contrast, and has high display quality. In addition, by providing a sacrificial layer (which may also be called a mask layer) on the EL layer, the damage that the EL layer receives during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0042] While it is difficult to reduce the spacing between adjacent light-emitting devices to less than 10 μm using, for example, a metal mask formation method, the above method allows for narrowing the spacing to less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, or even 1 μm or less. Furthermore, by using, for example, an exposure apparatus for LSIs, the spacing can be narrowed to less than 500 nm, less than 200 nm, less than 100 nm, and even less than 50 nm. This significantly reduces the area of ​​the non-emitting region that may exist between two light-emitting devices, making it possible to approach an aperture ratio of 100%. For example, an aperture ratio of 50% or more, 60% or more, 70% or more, 80% or more, and even 90% or more, can be achieved, and even less than 100%.

[0043] Furthermore, the pattern of the EL layer itself (which can also be called the processing size) can be made significantly smaller compared to when a metal mask is used. Also, for example, when a metal mask is used to create different EL layers, variations in thickness occur between the center and edges of the EL layer, resulting in a smaller effective area that can be used as an emitting region relative to the area of ​​the EL layer. On the other hand, with the above manufacturing method, a film deposited to a uniform thickness is processed, so island-shaped EL layers can be formed with a uniform thickness. Therefore, even with a fine pattern, almost the entire area can be used as an emitting region. As a result, a display device that combines high resolution and a high aperture ratio can be manufactured.

[0044] After forming EL layers that emit light of each color, the sacrificial layers remaining on each EL layer can be used as a hard mask to process the conductive film, thereby forming pixel electrodes. Since there is no need to separately provide a mask for forming the pixel electrodes in an island shape, the manufacturing cost of the display device can be reduced. Furthermore, since there is no need to provide an insulating layer to cover the edges of the pixel electrodes between the pixel electrodes and the EL layer, the spacing between adjacent light-emitting devices can be made extremely narrow. Therefore, the display device can be made higher resolution or more detailed. In addition, a mask for forming the insulating layer is also unnecessary, further reducing the manufacturing cost of the display device.

[0045] Here, the first layer and the second layer each include at least an emissive layer and preferably consist of multiple layers. Specifically, it is preferable to have one or more layers on the emissive layer. By having other layers between the emissive layer and the sacrificial layer, it is possible to suppress the exposure of the emissive layer to the outermost surface during the manufacturing process of the display device and reduce the damage the emissive layer receives. This can improve the reliability of the light-emitting device. Therefore, it is preferable that the first layer and the second layer each include an emissive layer and a carrier transport layer (electron transport layer or hole transport layer) on the emissive layer.

[0046] Furthermore, in light-emitting devices that emit light of different colors, it is not necessary to fabricate all the layers constituting the EL layer separately; some layers can be deposited in the same process. In a method for manufacturing a display device according to one aspect of the present invention, some of the layers constituting the EL layer are formed in island-like structures for each color, then the sacrificial layer is removed, and the remaining layers constituting the EL layer and a common electrode (also called an upper electrode) are formed in common (as a single film) for each color of light-emitting device. For example, the carrier injection layer and the common electrode can be formed in common for each color of light-emitting device. On the other hand, the carrier injection layer is often a relatively conductive layer within the EL layer. Therefore, there is a risk of the light-emitting device short-circuiting if the carrier injection layer comes into contact with the side surface of some of the island-like layers of the EL layer, or with the side surface of the pixel electrode. Furthermore, even when the carrier injection layer is provided in island-like structures and the common electrode is formed in common for each color of light-emitting device, there is a risk of the light-emitting device short-circuiting if the common electrode comes into contact with the side surface of the EL layer, or with the side surface of the pixel electrode.

[0047] Therefore, a display device according to one aspect of the present invention has a side wall (also called a side wall protective layer, side wall insulating film, insulating layer, etc.) that covers the side surface of the island-shaped light-emitting layer and the side surface of the pixel electrode.

[0048] This prevents at least a portion of the island-shaped EL layer and the pixel electrodes from coming into contact with the carrier injection layer or common electrode. Therefore, it is possible to suppress short circuits in the light-emitting device and improve the reliability of the light-emitting device.

[0049] A display device according to one aspect of the present invention includes a pixel electrode that functions as an anode, an island-shaped hole injection layer, a hole transport layer, an emissive layer, and an electron transport layer arranged in this order on the pixel electrode, a side wall provided to cover the respective sides of the pixel electrode, the hole injection layer, the hole transport layer, the emissive layer, and the electron transport layer, an electron injection layer provided on the electron transport layer, and a common electrode provided on the electron injection layer that functions as a cathode.

[0050] Alternatively, a display device according to one aspect of the present invention includes a pixel electrode that functions as a cathode, an island-shaped electron injection layer, an electron transport layer, an emissive layer, and a hole transport layer provided in this order on the pixel electrode, a side wall provided to cover the respective sides of the pixel electrode, the electron injection layer, the electron transport layer, the emissive layer, and the hole transport layer, a hole injection layer provided on the hole transport layer, and a common electrode provided on the hole injection layer that functions as an anode.

[0051] Alternatively, a display device according to one aspect of the present invention includes a pixel electrode, a first light-emitting unit on the pixel electrode, a charge generation layer (also called an intermediate layer) on the first light-emitting unit, a second light-emitting unit on the charge generation layer, side walls provided to cover the respective sides of the pixel electrode, the first light-emitting unit, the charge generation layer, and the second light-emitting unit, and a common electrode provided on the second light-emitting unit. Note that between the second light-emitting unit and the common electrode, one or both of an electron transport layer and an electron injection layer may be provided as a common layer for each color of light-emitting device.

[0052] Hole injection layers, electron injection layers, or charge generation layers are often relatively conductive layers within the EL layer. In a display device according to one aspect of the present invention, the sides of these layers are covered with an insulating layer, thereby suppressing contact with common electrodes and the like. Therefore, short circuits in the light-emitting device can be suppressed, and the reliability of the light-emitting device can be improved.

[0053] This configuration makes it possible to manufacture highly detailed, high-resolution, and reliable display devices. For example, it is not necessary to apply special pixel arrangement methods such as the PenTile method to artificially increase detail; even with an arrangement method that uses three or more subpixels per pixel, an extremely high-resolution display device can be realized. For example, with a so-called stripe arrangement in which R, G, and B are each arranged in one direction, a display device with a detail of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, even 3000 ppi or more, and even 5000 ppi or more can be realized.

[0054] The sidewall may be a single-layer structure or a multi-layer structure. In particular, it is preferable to use a two-layer sidewall structure. For example, since the first layer of the sidewall is formed in contact with the EL layer, it is preferable to form it using the atomic layer deposition (ALD) method, which minimizes film deposition damage. Furthermore, for the second layer of the sidewall, it is preferable to form it using the sputtering method, chemical vapor deposition (CVD) method, or plasma-enhanced chemical vapor deposition (PECVD) method, which have a faster film deposition rate than the ALD method. This makes it possible to manufacture highly reliable display devices with high productivity.

[0055] For example, an aluminum oxide film formed by the ALD method can be used for the first layer of the sidewall, and a silicon nitride film or silicon oxide nitride film formed by the sputtering method or PECVD method can be used for the second layer of the sidewall.

[0056] [Example of display device configuration 1] Figures 1A and 1B show a display device according to one embodiment of the present invention.

[0057] Figure 1A shows a top view of the display device 100. The display device 100 has a display unit in which a plurality of pixels 110 are arranged in a matrix, and a connection unit 140 outside the display unit. The connection unit 140 can also be called a cathode contact unit.

[0058] A stripe array is applied to pixel 110 shown in Figure 1A. Pixel 110 shown in Figure 1A is composed of three subpixels: subpixels 110a, 110b, and 110c. Each subpixel 110a, 110b, and 110c has a light-emitting device that emits light of a different color. Examples of subpixels 110a, 110b, and 110c include subpixels of three colors: red (R), green (G), and blue (B); and subpixels of three colors: yellow (Y), cyan (C), and magenta (M).

[0059] The top surface shape of the subpixel shown in Figure 1A corresponds to the top surface shape of the light-emitting region.

[0060] Furthermore, the circuit layout constituting the subpixel is not limited to the subpixel range shown in Figure 1A, but may be located outside of it. For example, some or all of the transistors in subpixel 110a may be located outside the range of subpixel 110a shown in Figure 1A. For example, the transistors in subpixel 110a may have a portion located within the range of subpixel 110b, or a portion located within the range of subpixel 110c.

[0061] In Figure 1A, the aperture ratios (size, also known as the size of the light-emitting area) of the sub-pixels 110a, 110b, and 110c are shown to be equal or approximately equal, but one aspect of the present invention is not limited thereto. The aperture ratios of the sub-pixels 110a, 110b, and 110c can be determined as appropriate. The aperture ratios of the sub-pixels 110a, 110b, and 110c may be different, or two or more may be equal or approximately equal.

[0062] Figure 1A shows an example where subpixels of different colors are arranged in the X direction, and subpixels of the same color are arranged in the Y direction. Alternatively, subpixels of different colors may be arranged in the Y direction, and subpixels of the same color may be arranged in the X direction.

[0063] Figure 1A shows an example where the connection portion 140 is located below the display portion in a top view, but it is not particularly limited. The connection portion 140 only needs to be provided at least one location on the top, right, left, or bottom of the display portion in a top view, and may be provided so as to surround all four sides of the display portion. Also, the connection portion 140 may be singular or multiple.

[0064] Figure 1B shows a cross-sectional view between the dashed line X1 and X2 in Figure 1A.

[0065] As shown in Figure 1B, the display device 100 has light-emitting devices 130a, 130b, and 130c arranged on a layer 101 containing transistors, and protective layers 131 and 132 are provided to cover these light-emitting devices. A substrate 120 is bonded to the protective layer 132 by a resin layer 122. In addition, a side wall 125a and a side wall 125b on the side wall 125a are provided in the region between adjacent light-emitting devices.

[0066] A display device according to one aspect of the present invention may be a top-emission type that emits light in the direction opposite to the substrate on which the light-emitting device is formed, a bottom-emission type that emits light toward the substrate on which the light-emitting device is formed, or a dual-emission type that emits light on both sides.

[0067] The layer 101 containing transistors can be, for example, a laminated structure in which multiple transistors are provided on a substrate and an insulating layer is provided to cover these transistors. The layer 101 containing transistors may have recesses between adjacent light-emitting devices. For example, recesses may be provided in the insulating layer located on the outermost surface of the layer 101 containing transistors. Examples of the configuration of the layer 101 containing transistors will be described later in Embodiments 3 and 4.

[0068] Each of the light-emitting devices 130a, 130b, and 130c emits light of a different color. Preferably, the light-emitting devices 130a, 130b, and 130c are a combination that emits, for example, red (R), green (G), and blue (B) light.

[0069] As the light-emitting devices 130a, 130b, and 130c, it is preferable to use, for example, OLED (Organic Light Emitting Diode) or QLED (Quantum-dot Light Emitting Diode). Examples of light-emitting materials (also referred to as luminescent materials) that the light-emitting devices possess include fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF) materials. As the TADF material, a material in which the singlet excited state and the triplet excited state are in thermal equilibrium may be used. Since such TADF materials have a shorter emission lifetime (excitation lifetime), it is possible to suppress the decrease in efficiency in the high-brightness region of the light-emitting device. In addition, inorganic compounds (such as quantum dot materials) may be used as the light-emitting material of the light-emitting device.

[0070] The light-emitting device has an EL layer between a pair of electrodes. In this specification, one of the pair of electrodes may be referred to as the pixel electrode and the other as the common electrode.

[0071] In a light-emitting device, one electrode functions as the anode and the other as the cathode. The following explanation uses the example where the pixel electrode functions as the anode and the common electrode functions as the cathode.

[0072] The light-emitting device 130a includes a pixel electrode 111a on a layer 101 containing a transistor, an island-shaped first layer 113a on the pixel electrode 111a, a fifth layer 114 on the island-shaped first layer 113a, and a common electrode 115 on the fifth layer 114.

[0073] In this embodiment, the light-emitting device will be described using a tandem structure as an example. Therefore, the light-emitting device of this embodiment has a plurality of light-emitting units, each having a light-emitting layer, with a charge-generating layer between two of the light-emitting units. There are no particular limitations on the configuration of the light-emitting device, and it may also have a single structure. An example of the configuration of the light-emitting device will be described later in Embodiment 2.

[0074] The first layer 113a includes a first light-emitting unit 181a on the pixel electrode 111a, a charge generation layer 182a on the first light-emitting unit 181a, and a second light-emitting unit 183a on the charge generation layer 182a. In the light-emitting device 130a, the first layer 113a and the fifth layer 114 can be collectively called the EL layer. The first light-emitting unit 181a and the second light-emitting unit 183a may be configured to emit light of the same color, or they may be configured to emit light of different colors.

[0075] The light-emitting device 130b includes a pixel electrode 111b on a layer 101 containing a transistor, an island-shaped second layer 113b on the pixel electrode 111b, a fifth layer 114 on the island-shaped second layer 113b, and a common electrode 115 on the fifth layer 114. The second layer 113b includes a first light-emitting unit 181b on the pixel electrode 111b, a charge generation layer 182b on the first light-emitting unit 181b, and a second light-emitting unit 183b on the charge generation layer 182b. In the light-emitting device 130b, the second layer 113b and the fifth layer 114 can be collectively called the EL layer. The first light-emitting unit 181b and the second light-emitting unit 183b may be configured to emit light of the same color, or they may be configured to emit light of different colors.

[0076] The light-emitting device 130c includes a pixel electrode 111c on a layer 101 containing a transistor, an island-shaped third layer 113c on the pixel electrode 111c, a fifth layer 114 on the island-shaped third layer 113c, and a common electrode 115 on the fifth layer 114. The third layer 113c includes a first light-emitting unit 181c on the pixel electrode 111c, a charge generation layer 182c on the first light-emitting unit 181c, and a second light-emitting unit 183c on the charge generation layer 182c. In the light-emitting device 130c, the third layer 113c and the fifth layer 114 can be collectively called the EL layer. The first light-emitting unit 181c and the second light-emitting unit 183c may be configured to emit light of the same color, or they may be configured to emit light of different colors.

[0077] Each color of light-emitting device shares the same film as a common electrode. This common electrode, which is common to all colored light-emitting devices, is electrically connected to a conductive layer provided in the connection section 140.

[0078] Of the pixel electrodes and common electrodes, the electrode that extracts light should preferably use a conductive film that transmits visible light. Furthermore, it is preferable to use a conductive film that reflects visible light on the electrode that does not extract light.

[0079] As materials for forming the pair of electrodes (pixel electrode and common electrode) of a light-emitting device, metals, alloys, electrically conductive compounds, and mixtures thereof can be used as appropriate. Specifically, examples include indium tin oxide (In-Sn oxide, also called ITO), In-Si-Sn oxide (also called ITSO), indium zinc oxide (In-Zn oxide), In-W-Zn oxide, aluminum-containing alloys such as aluminum, nickel, and lanthanum alloys (Al-Ni-La), as well as silver-containing alloys such as silver-magnesium alloys and silver-palladium-copper alloys (Ag-Pd-Cu, also written as APC). In addition, metals such as aluminum (Al), magnesium (Mg), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys containing these in appropriate combinations can also be used. Furthermore, elements belonging to Group 1 or Group 2 of the periodic table not exemplified above (e.g., lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these in appropriate combinations, graphene, and the like can also be used.

[0080] It is preferable that the light-emitting device has a microcavity structure. Therefore, it is preferable that one of the pair of electrodes in the light-emitting device has an electrode that is transparent to and reflective to visible light (a semi-transmissive / semi-reflective electrode), and the other has an electrode that is reflective to visible light (a reflective electrode). By having a microcavity structure in the light-emitting device, the light emitted from the light-emitting layer can be resonated between the two electrodes, thereby strengthening the light emitted from the light-emitting device.

[0081] Furthermore, semi-transmissive / semi-reflective electrodes can have a laminated structure consisting of a reflective electrode and an electrode that transmits visible light (also called a transparent electrode).

[0082] The light transmittance of the transparent electrode shall be 40% or more. For example, it is preferable to use an electrode in the light-emitting device that has a transmittance of 40% or more for visible light (light with a wavelength of 400 nm or more and less than 750 nm). The visible light reflectance of the semi-transparent / semi-reflective electrode shall be 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes shall be 1 × 10⁻⁶ -2 A value of Ωcm or less is preferable.

[0083] The first layer 113a, the second layer 113b, and the third layer 113c are each provided in an island-like manner. The first layer 113a, the second layer 113b, and the third layer 113c each have an emissive layer. Preferably, the first layer 113a, the second layer 113b, and the third layer 113c each have an emissive layer that emits light of a different color.

[0084] The luminescent layer is a layer containing a luminescent material. The luminescent layer may contain one or more types of luminescent materials. Suitable luminescent materials include those exhibiting colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red. Furthermore, materials emitting near-infrared light may also be used as luminescent materials.

[0085] Examples of luminescent materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0086] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0087] Examples of phosphorescent materials include organometallic complexes (especially iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton; organometallic complexes (especially iridium complexes) using phenylpyridine derivatives having electron-withdrawing groups as ligands; platinum complexes; and rare earth metal complexes.

[0088] The light-emitting layer may contain one or more types of organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). One or more of these organic compounds may be hole-transporting materials and / or electron-transporting materials. Alternatively, one or more of these organic compounds may be bipolar materials or TADF materials.

[0089] The light-emitting layer preferably comprises, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that readily forms an excitation complex. This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excitation complex to the light-emitting substance (phosphorescent material). By selecting a combination that forms an excitation complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the light-emitting substance, energy transfer becomes smoother, and light emission can be obtained efficiently. This configuration simultaneously achieves high efficiency, low-voltage operation, and a long lifespan for the light-emitting device.

[0090] The first layer 113a, the second layer 113b, and the third layer 113c may further include layers other than the light-emitting layer that contain a material with high hole injection properties, a material with high hole transport properties (also called a hole-transporting material), a hole-blocking material, a material with high electron transport properties (also called an electron-transporting material), a material with high electron injection properties, an electron-blocking material, or a bipolar material (a material with high electron transport and hole transport properties, also called a bipolar material).

[0091] For example, the first layer 113a, the second layer 113b, and the third layer 113c may each have one or more of the following: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0092] Among the EL layers, one or more of the following layers can be applied to be commonly formed in each color light-emitting device: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer. For example, a carrier injection layer (hole injection layer or electron injection layer) may be formed as the fifth layer 114. Furthermore, all layers of the EL layer may be manufactured separately for each color. In other words, the EL layer does not necessarily have to have layers commonly formed in each color light-emitting device.

[0093] Preferably, the second light-emitting units 183a, 183b, and 183c each have a light-emitting layer and a carrier transport layer on the light-emitting layer. This suppresses exposure of the light-emitting layer to the outermost surface during the manufacturing process of the display device 100, thereby reducing damage to the light-emitting layer. This improves the reliability of the light-emitting device.

[0094] The sides of the pixel electrodes 111a, 111b, 111c, the first layer 113a, the second layer 113b, and the third layer 113c are covered by sidewalls 125a, 125b, and these sidewalls 125a, 125b are located between the sides of these layers and the fifth layer 114 (or common electrode 115). This prevents the fifth layer 114 (or common electrode 115) from coming into contact with any of the sides of the pixel electrodes 111a, 111b, 111c, the first layer 113a, the second layer 113b, and the third layer 113c, thereby preventing a short circuit in the light-emitting device.

[0095] The hole injection layer is a layer that injects holes from the anode into the hole transport layer, and is a layer containing a material with high hole injection capabilities. Examples of materials with high hole injection capabilities include aromatic amine compounds and composite materials containing hole transport materials and acceptor materials (electron-accepting materials).

[0096] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light-emitting layer. The hole transport layer is a layer containing a hole-transporting material. The hole-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having a hole mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher hole transport capabilities than electron transport. Preferred hole transport materials include π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, furan derivatives, etc.) and aromatic amines (compounds having an aromatic amine skeleton), which are materials with high hole transport capabilities.

[0097] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light-emitting layer. The electron transport layer is a layer containing an electron-transporting material. The electron-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having an electron mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes. Examples of electron-transporting materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds, which are all highly electron-transporting materials.

[0098] The electron injection layer is a layer that injects electrons from the cathode into the electron transport layer, and is a layer containing a material with high electron-injection properties. Alkali metals, alkaline earth metals, or compounds thereof can be used as materials with high electron-injection properties. Composite materials containing both electron-transporting materials and donor materials (electron-donating materials) can also be used as materials with high electron-injection properties.

[0099] Examples of electron injection layers include lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), and calcium fluoride (CaF). x (where X is any number), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatrium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatrium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatrium (abbreviation: LiPPP), lithium oxide (LiO x Alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. Furthermore, the electron injection layer may be a multilayer structure of two or more layers. For example, this multilayer structure may consist of lithium fluoride as the first layer and ytterbium as the second layer.

[0100] Alternatively, an electron-transporting material may be used as the electron injection layer. For example, a compound having a lone pair of electrons and an electron-deficient heteroaromatic ring can be used as the electron-transporting material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), or a triazine ring can be used.

[0101] Furthermore, it is preferable that the lowest unoccupied molecular orbital (LUMO) of an organic compound containing a lone pair of electrons is between -3.6 eV and -2.3 eV. In addition, the highest occupied molecular orbital (HOMO) level and LUMO level of an organic compound can generally be estimated by methods such as cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy.

[0102] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz) can be used in organic compounds containing lone pairs of electrons. NBPhen has a higher glass transition temperature (Tg) and superior heat resistance compared to BPhen.

[0103] Furthermore, when fabricating a tandem light-emitting device, a charge generation layer is provided between the two light-emitting units. The charge generation layer has at least a charge generation region. When a voltage is applied between the pair of electrodes, the charge generation layer has the function of injecting electrons into one of the two light-emitting units and holes into the other.

[0104] As described above, the charge generation layer has at least a charge generation region. The charge generation region preferably contains an acceptor material, and preferably contains, for example, a hole transport material and an acceptor material applicable to the hole injection layer described above.

[0105] Furthermore, the charge generation layer preferably includes a layer containing a material with high electron injection properties. This layer can also be called an electron injection buffer layer. The electron injection buffer layer is preferably provided between the charge generation region and the electron transport layer. By providing an electron injection buffer layer, the injection barrier between the charge generation region and the electron transport layer can be relaxed, allowing electrons generated in the charge generation region to be easily injected into the electron transport layer.

[0106] The electron injection buffer layer preferably contains an alkali metal or an alkaline earth metal, and can, for example, a compound of an alkali metal or an alkaline earth metal. Specifically, the electron injection buffer layer preferably has an inorganic compound containing an alkali metal and oxygen, or an inorganic compound containing an alkaline earth metal and oxygen, and more preferably has an inorganic compound containing lithium and oxygen (such as lithium oxide (Li2O)). In addition, any other material applicable to the electron injection layer can be suitably used for the electron injection buffer layer.

[0107] The charge generation layer preferably has a layer containing a material with high electron transport properties. This layer can also be called an electron relay layer. The electron relay layer is preferably provided between the charge generation region and the electron injection buffer layer. If the charge generation layer does not have an electron injection buffer layer, the electron relay layer is preferably provided between the charge generation region and the electron transport layer. The electron relay layer has the function of preventing interaction between the charge generation region and the electron injection buffer layer (or electron transport layer) and smoothly transferring electrons.

[0108] As the electron relay layer, it is preferable to use a phthalocyanine-based material such as copper(II) phthalocyanine (abbreviated as CuPc), or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0109] Furthermore, the charge generation region, electron injection buffer layer, and electron relay layer described above may not be clearly distinguishable depending on their cross-sectional shape or characteristics.

[0110] The charge generation layer may have a donor material instead of an acceptor material. For example, the charge generation layer may have a layer containing an electron transport material and a donor material, which is applicable to the electron injection layer described above.

[0111] When stacking light-emitting units, the rise in driving voltage can be suppressed by providing a charge generation layer between the two light-emitting units.

[0112] The light-emitting device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-emitting device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0113] For the side walls 125a and 125b, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used, respectively. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxidative nitride insulating films include silicon oxide nitride films and aluminum oxide nitride films. Examples of nitride oxide insulating films include silicon oxide nitride films and aluminum oxide nitride films.

[0114] In this specification, the term "oxidogenic nitride" refers to a material in which the oxygen content is greater than the nitrogen content, and the term "nitride oxide" refers to a material in which the nitrogen content is greater than the oxygen content.

[0115] Since the sidewall 125a is formed in contact with the first layer 113a, the second layer 113b, and the third layer 113c, it is preferable to form it using the ALD method, which minimizes film formation damage. For example, it is preferable to use an aluminum oxide film formed by the ALD method for the sidewall 125a.

[0116] The sidewall 125b is preferably formed using a sputtering method, CVD method, or PECVD method, which have a faster film deposition rate than the ALD method. For example, a silicon nitride film formed by the sputtering method or a silicon nitride oxide film formed by the PECVD method can be used for the sidewall 125b. This makes it possible to manufacture highly reliable display devices with high productivity.

[0117] It is preferable to have protective layers 131 and 132 on the light-emitting devices 130a, 130b, and 130c. Providing protective layers 131 and 132 can improve the reliability of the light-emitting devices. In this embodiment, a two-layer structure of protective layers 131 and 132 is described as an example, but the protective layers may be a single layer or a laminated structure of three or more layers.

[0118] The conductivity of the protective layers 131 and 132 is not required. At least one of an insulating film, a semiconductor film, and a conductive film can be used as the protective layers 131 and 132.

[0119] The presence of inorganic films in the protective layers 131 and 132 prevents oxidation of the common electrode 115 and suppresses the intrusion of impurities (such as moisture and oxygen) into the light-emitting devices 130a, 130b, and 130c, thereby suppressing degradation of the light-emitting devices and improving the reliability of the display device.

[0120] For the protective layers 131 and 132, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxidative nitride insulating films include silicon oxide nitride films and aluminum oxide nitride films. Examples of nitride oxide insulating films include silicon oxide nitride films and aluminum oxide nitride films.

[0121] The protective layers 131 and 132 preferably each have a nitride insulating film or a nitride oxide insulating film, and more preferably a nitride insulating film.

[0122] Furthermore, the protective layers 131 and 132 may also be made of an inorganic film containing In-Sn oxide (also known as ITO), In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or indium gallium zinc oxide (In-Ga-Zn oxide, also known as IGZO). The inorganic film is preferably highly resistive, and more specifically, it is preferably more resistive than the common electrode 115. The inorganic film may further contain nitrogen.

[0123] When the light emitted from a light-emitting device is extracted via protective layers 131 and 132, it is preferable that the protective layers 131 and 132 have high transmittance to visible light. For example, ITO, IGZO, and aluminum oxide are preferred because they are inorganic materials with high transmittance to visible light.

[0124] For example, protective layers 131 and 132 can be a laminated structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a laminated structure of an aluminum oxide film and an IGZO film on the aluminum oxide film. By using such a laminated structure, it is possible to suppress the penetration of impurities (water, oxygen, etc.) into the EL layer.

[0125] Furthermore, the protective layers 131 and 132 may have an organic film. For example, the protective layer 132 may have both an organic film and an inorganic film.

[0126] Different film deposition methods may be used for protective layer 131 and protective layer 132. Specifically, protective layer 131 may be formed using atomic layer deposition (ALD), and protective layer 132 may be formed using sputtering.

[0127] The upper edges of the pixel electrodes 111a, 111b, and 111c are not covered by an insulating layer. Therefore, the spacing between adjacent light-emitting devices can be made extremely narrow. Consequently, a high-definition or high-resolution display device can be achieved.

[0128] In this specification, devices fabricated using a metal mask or an FMM (Fine Metal Mask, a high-resolution metal mask) may be referred to as MM (Metal Mask) structured devices. Furthermore, in this specification, devices fabricated without using a metal mask or an FMM may be referred to as MML (Metal Maskless) structured devices.

[0129] In this specification, a structure in which different light-emitting layers are created or painted for each color of light-emitting device (here, blue (B), green (G), and red (R)) may be referred to as an SBS (Side By Side) structure. The SBS structure allows for the optimization of materials and configuration for each light-emitting device, thus increasing the freedom of material and configuration selection and making it easier to improve brightness and reliability.

[0130] Furthermore, in this specification, a light-emitting device capable of emitting white light may be referred to as a white light-emitting device. A white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0131] Furthermore, light-emitting devices can be broadly classified into single structures and tandem structures. A single-structure device has one light-emitting unit between a pair of electrodes, and it is preferable that the light-emitting unit includes one or more light-emitting layers. When obtaining white light emission using two light-emitting layers, the light-emitting layers should be selected such that their emission colors are complementary. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary, a configuration that emits white light as a whole can be obtained. Also, when obtaining white light emission using three or more light-emitting layers, the combination of the emission colors of the three or more light-emitting layers should result in a configuration that emits white light as a whole.

[0132] A tandem device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, the light from the light-emitting layers of the multiple light-emitting units should be combined to produce white light emission. The configuration for obtaining white light emission is the same as for a single-structure device. In a tandem device, it is preferable to provide a charge-generating layer between the multiple light-emitting units.

[0133] Furthermore, when comparing the aforementioned white light-emitting devices (single or tandem structure) with SBS structure light-emitting devices, SBS structure light-emitting devices can consume less power than white light-emitting devices. If you want to keep power consumption low, it is preferable to use SBS structure light-emitting devices. On the other hand, white light-emitting devices are preferable because their manufacturing process is simpler than that of SBS structure light-emitting devices, which can lead to lower manufacturing costs or higher manufacturing yields.

[0134] The display device of this embodiment can reduce the distance between light-emitting devices. Specifically, the distance between light-emitting devices, the distance between EL layers, or the distance between pixel electrodes can be less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 10 nm or less. In other words, the distance between the side surface of the first layer 113a and the side surface of the second layer 113b, or the distance between the side surface of the second layer 113b and the side surface of the third layer 113c, has a region of 1 μm or less, preferably a region of 0.5 μm (500 nm) or less, and more preferably a region of 100 nm or less.

[0135] A light-shielding layer may be provided on the surface of the substrate 120 facing the resin layer 122. Various optical components can also be placed on the outside of the substrate 120. Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (such as diffusion films), anti-reflective layers, and light-collecting films. Furthermore, an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, and an impact-absorbing layer may also be placed on the outside of the substrate 120.

[0136] The substrate 120 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, etc. The substrate on the side that extracts light from the light-emitting device should be made of a material that transmits the light. If a flexible material is used for the substrate 120, the flexibility of the display device can be increased, and a flexible display can be realized. Alternatively, a polarizing plate may be used as the substrate 120.

[0137] As the substrate 120, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. may be used. Glass with a thickness sufficient to provide flexibility may also be used as the substrate 120.

[0138] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy for the substrate of the display device. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence).

[0139] For substrates with high optical isotropy, the absolute value of the retardation (phase difference) is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0140] Examples of films with high optical isotropy include triacetylcellulose (TAC, also known as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0141] Furthermore, when using a film as the substrate, the film may absorb water, potentially causing wrinkles or other shape changes in the display panel. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferable to use a film with a water absorption rate of 0.1% or less, and even more preferable to use a film with a water absorption rate of 0.01% or less.

[0142] As the resin layer 122, various types of curing adhesives can be used, such as UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0143] Materials that can be used for conductive layers such as the gate, source, and drain of transistors, as well as various wirings and electrodes that constitute display devices, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys mainly composed of these metals. Films containing these materials can be used as single layers or in a multilayer structure.

[0144] Furthermore, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene can be used as the light-transmitting conductive material. Alternatively, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metallic materials, can be used. Alternatively, nitrides of such metallic materials (e.g., titanium nitride) may be used. When using metallic materials or alloy materials (or their nitrides), it is preferable to make them thin enough to be light-transmitting. In addition, a laminated film of the above materials can be used as a conductive layer. For example, using a laminated film of a silver-magnesium alloy and indium tin oxide is preferable because it can enhance conductivity. These can also be used as conductive layers for various wirings and electrodes that constitute a display device, and as conductive layers (conductive layers that function as pixel electrodes or common electrodes) in light-emitting devices.

[0145] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide, and aluminum oxide.

[0146] As shown in Figure 2A, a pixel can be configured to have four types of subpixels.

[0147] Figure 2A shows a top view of the display device 100. The display device 100 has a display unit in which a plurality of pixels 110 are arranged in a matrix, and a connection unit 140 outside the display unit.

[0148] The pixel 110 shown in Figure 2A is composed of four types of subpixels: subpixels 110a, 110b, 110c, and 110d. Each of the subpixels 110a, 110b, 110c, and 110d has a light-emitting device that emits light of a different color. Examples of subpixels 110a, 110b, 110c, and 110d include subpixels of four colors: R, G, B, and white (W), and subpixels of four colors: R, G, B, and Y.

[0149] Figure 2A shows an example where one pixel 110 is composed of two rows and three columns. Pixel 110 has three subpixels (subpixels 110a, 110b, and 110c) in the top row (1st row) and three subpixels 110d in the bottom row (2nd row). In other words, pixel 110 has subpixels 110a and 110d in the left column (1st column), subpixels 110b and 110d in the middle column (2nd column), and subpixels 110c and 110d in the right column (3rd column). As shown in Figure 2A, by aligning the arrangement of subpixels in the top row and the bottom row, it becomes possible to efficiently remove dust and other debris that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided.

[0150] Figure 2B shows a cross-sectional view of the section between X3 and X4 shown by the dashed line in Figure 2A. The configuration shown in Figure 2B is the same as that in Figure 1B, except that it has a light-emitting device 130d. Therefore, the explanation of the parts that are the same as in Figure 1B will be omitted.

[0151] As shown in Figure 2B, the display device 100 has light-emitting devices 130a, 130b, 130c, and 130d arranged on a layer 101 containing transistors, and protective layers 131 and 132 are provided to cover these light-emitting devices. A substrate 120 is bonded to the protective layer 132 by a resin layer 122. In addition, a side wall 125a and a side wall 125b on the side wall 125a are provided in the region between adjacent light-emitting devices.

[0152] Each of the light-emitting devices 130a, 130b, 130c, and 130d emits light of a different color. Preferably, the light-emitting devices 130a, 130b, 130c, and 130d are a combination that emits four colors of light, for example, red (R), green (G), blue (B), and white (W).

[0153] The light-emitting device 130d includes a pixel electrode 111d on a layer 101 containing a transistor, an island-shaped fourth layer 113d on the pixel electrode 111d, a fifth layer 114 on the island-shaped fourth layer 113d, and a common electrode 115 on the fifth layer 114.

[0154] The fourth layer 113d includes a first light-emitting unit 181d on the pixel electrode 111d, a charge generation layer 182d on the first light-emitting unit 181d, and a second light-emitting unit 183d on the charge generation layer 182d. In the light-emitting device 130d, the fourth layer 113d and the fifth layer 114 can be collectively referred to as the EL layer.

[0155] Each of the three subpixels 110d may have its own independent light-emitting device 130d, or they may share a single light-emitting device 130d. In other words, a pixel 110 may have one light-emitting device 130d, or it may have three.

[0156] [Pixel layout] Next, we will describe a pixel layout different from Figures 1A and 2A. 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.

[0157] Furthermore, the top surface shape of a sub-pixel can be, for example, a polygon such as a triangle, quadrilateral (including rectangles and squares), or pentagon, or a polygon with rounded corners, or an ellipse or a circle. Here, the top surface shape of a sub-pixel corresponds to the top surface shape of the light-emitting region of the light-emitting device.

[0158] The pixel 110 shown in Figure 3A has an S-stripe array applied to it. The pixel 110 shown in Figure 3A is composed of three subpixels: subpixels 110a, 110b, and 110c. For example, as shown in Figure 4A, subpixel 110a may be a blue subpixel B, subpixel 110b may be a red subpixel R, and subpixel 110c may be a green subpixel G.

[0159] The pixel 110 shown in Figure 3B includes a sub-pixel 110a with a roughly trapezoidal top surface shape with rounded corners, a sub-pixel 110b with a roughly triangular top surface shape with rounded corners, and a sub-pixel 110c with a roughly quadrilateral or hexagonal top surface shape with rounded corners. Furthermore, sub-pixel 110a has a larger light-emitting area than sub-pixel 110b. Thus, the shape and size of each sub-pixel can be determined independently. For example, the size of a sub-pixel can be reduced to a level that provides a more reliable light-emitting device. For example, as shown in Figure 4B, sub-pixel 110a may be a green sub-pixel G, sub-pixel 110b may be a red sub-pixel R, and sub-pixel 110c may be a blue sub-pixel B.

[0160] A Pentile array is applied to pixels 124a and 124b shown in Figure 3C. Figure 3C shows an example in which pixels 124a having subpixels 110a and 110b, and pixels 124b having subpixels 110b and 110c are arranged alternately. For example, as shown in Figure 4C, subpixel 110a may be a red subpixel R, subpixel 110b may be a green subpixel G, and subpixel 110c may be a blue subpixel B.

[0161] Pixels 124a and 124b shown in Figures 3D and 3E utilize a delta array. Pixel 124a has two subpixels (subpixels 110a and 110b) in the top row (1st row) and one subpixel (subpixel 110c) in the bottom row (2nd row). Pixel 124b has one subpixel (subpixel 110c) in the top row (1st row) and two subpixels (subpixels 110a and 110b) in the bottom row (2nd row). For example, as shown in Figure 4D, subpixel 110a may be a red subpixel R, subpixel 110b a green subpixel G, and subpixel 110c a blue subpixel B.

[0162] Figure 3D shows an example where each subpixel has a roughly square top shape with rounded corners, and Figure 3E shows an example where each subpixel has a circular top shape.

[0163] Figure 3F shows an example where the subpixels of each color are arranged in a zigzag pattern. Specifically, in a top view, the upper edges of two subpixels aligned in the column direction (for example, subpixels 110a and 110b, or subpixels 110b and 110c) are offset. For example, as shown in Figure 4E, subpixel 110a could be the red subpixel R, subpixel 110b could be the green subpixel G, and subpixel 110c could be the blue subpixel B.

[0164] In photolithography, the finer the pattern being processed, the more significant the effects of light diffraction become. This compromises the fidelity of the transfer of the photomask pattern through exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, patterns with rounded corners are likely to be formed. Consequently, the top surface shape of subpixels may be a polygon with rounded corners, an ellipse, or a circle.

[0165] Furthermore, in a method for manufacturing a display device according to one aspect of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the EL layer material and the curing temperature of the resist material, the curing of the resist film may be insufficient. A resist film that is not sufficiently cured may take a shape that deviates from the desired shape during processing. As a result, the top surface shape of the EL layer may become a polygon with rounded corners, an ellipse, or a circle. For example, if an attempt is made to form a resist mask with a square top surface, a resist mask with a circular top surface may be formed, resulting in a circular top surface shape for the EL layer.

[0166] Furthermore, in order to achieve the desired shape of the upper surface of the EL layer, a technique (OPC (Optical Proximity Correction) technique) may be used to pre-correct the mask pattern so that the design pattern and the transferred pattern match. Specifically, in the OPC technique, a correction pattern is added to the corners of the shape on the mask pattern.

[0167] Furthermore, even in the pixel 110 to which the stripe arrangement shown in Figure 1A is applied, for example, as shown in Figure 4F, sub-pixel 110a can be a red sub-pixel R, sub-pixel 110b can be a green sub-pixel G, and sub-pixel 110c can be a blue sub-pixel B.

[0168] The pixels 110 shown in Figures 5A to 5C have a stripe arrangement applied to them.

[0169] Figure 5A shows an example where each subpixel has a rectangular top surface shape, Figure 5B shows an example where each subpixel has a top surface shape formed by connecting two semicircles and a rectangle, and Figure 5C shows an example where each subpixel has an elliptical top surface shape.

[0170] The pixels 110 shown in Figures 5D to 5F have a matrix array applied to them.

[0171] Figure 5D shows an example where each subpixel has a square top surface shape, Figure 5E shows an example where each subpixel has a roughly square top surface shape with rounded corners, and Figure 5F shows an example where each subpixel has a circular top surface shape.

[0172] The pixel 110 shown in Figures 5A to 5F is composed of four subpixels: subpixels 110a, 110b, 110c, and 110d. Each subpixel 110a, 110b, 110c, and 110d has a light-emitting device that emits light of a different color. For example, subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and white subpixels, respectively. For example, as shown in Figures 6A and 6B, subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and white subpixels, respectively. Alternatively, subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and infrared emitting subpixels, respectively.

[0173] Figure 5G shows an example where a single pixel 110 is composed of 2 rows and 3 columns. Pixel 110 has three subpixels (subpixels 110a, 110b, and 110c) in the top row (row 1) and one subpixel (subpixel 110d) in the bottom row (row 2). In other words, pixel 110 has subpixel 110a in the left column (column 1), subpixel 110b in the middle column (column 2), subpixel 110c in the right column (column 3), and subpixel 110d across these three columns.

[0174] Furthermore, in the pixel 110 shown in Figures 2A and 5G, for example, as shown in Figures 6C and 6D, sub-pixel 110a can be a red sub-pixel R, sub-pixel 110b can be a green sub-pixel G, sub-pixel 110c can be a blue sub-pixel B, and sub-pixel 110d can be a white sub-pixel W.

[0175] A display device according to one aspect of the present invention may have a light-receiving device in each pixel.

[0176] Of the four types of subpixels that pixel 110 has as shown in Figure 2A, three may be configured to have light-emitting devices and the remaining one to have a light-receiving device.

[0177] For example, a pn-type or pin-type photodiode can be used as the light-receiving device. The light-receiving device functions as a photoelectric conversion device (also called a photoelectric conversion element) that detects light incident on it and generates an electric charge. The amount of charge generated from the light-receiving device is determined by the amount of light incident on it.

[0178] In particular, it is preferable to use an organic photodiode having a layer containing an organic compound as the light-receiving device. Organic photodiodes can be easily made thinner, lighter, and larger in area, and because they offer a high degree of freedom in shape and design, they can be applied to various display devices.

[0179] In one aspect of the present invention, an organic EL device is used as the light-emitting device, and an organic photodiode is used as the light-receiving device. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be incorporated into a display device using an organic EL device.

[0180] The light-receiving device has at least an active layer functioning as a photoelectric conversion layer between a pair of electrodes. In this specification, one of the pair of electrodes may be referred to as the pixel electrode and the other as the common electrode.

[0181] For example, sub-pixels 110a, 110b, and 110c may be sub-pixels of three colors, R, G, and B, and sub-pixel 110d may be a sub-pixel having a light-receiving device. In this case, the fourth layer 113d has at least an active layer.

[0182] In a photodetector, one electrode functions as the anode and the other as the cathode. The following explanation uses the example where the pixel electrode functions as the anode and the common electrode functions as the cathode. The photodetector can detect incoming light, generate an electric charge, and extract it as an electric current by applying a reverse bias between the pixel electrode and the common electrode. Alternatively, the pixel electrode may function as the cathode and the common electrode as the anode.

[0183] The same manufacturing methods as for light-emitting devices can be applied to light-receiving devices. The island-shaped active layer (also called the photoelectric conversion layer) of the light-receiving device is not formed using a fine metal mask, but rather by depositing a film that will become the active layer onto one surface and then processing it, so that the island-shaped active layer can be formed with a uniform thickness. In addition, by providing a sacrificial layer on the active layer, the damage that the active layer receives during the manufacturing process of the display device can be reduced, and the reliability of the light-receiving device can be improved.

[0184] Here, the layers shared by the light-receiving device and the light-emitting device may have different functions in the light-emitting device and the light-receiving device. In this specification, components may be named based on their functions in the light-emitting device. For example, the hole injection layer functions as a hole injection layer in the light-emitting device and as a hole transport layer in the light-receiving device. Similarly, the electron injection layer functions as an electron injection layer in the light-emitting device and as an electron transport layer in the light-receiving device. Also, the layers shared by the light-receiving device and the light-emitting device may have the same functions in the light-emitting device and the light-receiving device. The hole transport layer functions as a hole transport layer in both the light-emitting device and the light-receiving device, and the electron transport layer functions as an electron transport layer in both the light-emitting device and the light-receiving device.

[0185] The active layer of the light-receiving device contains a semiconductor. Examples of such semiconductors include inorganic semiconductors such as silicon and organic semiconductors containing organic compounds. In this embodiment, an example of using an organic semiconductor as the semiconductor in the active layer is shown. Using an organic semiconductor is preferable because the light-emitting layer and the active layer can be formed by the same method (e.g., vacuum deposition method), and the manufacturing equipment can be shared.

[0186] Examples of the material of the n-type semiconductor in the active layer include electron-accepting organic semiconductor materials such as fullerenes (e.g., C 60 Fullerene, C 70 Fullerenes, etc.), fullerene derivatives, etc. Fullerenes have a shape like a soccer ball, and this shape is energetically stable. Fullerenes have deep (low) HOMO levels and LUMO levels. Due to the deep LUMO level of fullerenes, they have extremely high electron-accepting (acceptor) properties. Usually, when π-electron conjugation (resonance) spreads in a plane like benzene, the electron-donating (donor) property increases. However, since fullerenes have a spherical shape, despite the large spread of π-electrons, they have high electron-accepting properties. High electron-accepting properties are beneficial for a light-receiving device because they cause efficient charge separation at high speed. C 60 Fullerene, C70 Both fullerenes and C have a broad absorption band in the visible light region, and C 70 Fullerenes are C 60 Compared to fullerenes, it is preferable because it has a larger π-electron conjugation system and a broad absorption band in the long-wavelength region. Other examples of fullerene derivatives include [6,6]-Phenyl-C71-butyric acid methyl ester (abbreviated as PC70BM), [6,6]-Phenyl-C61-butyric acid methyl ester (abbreviated as PC60BM), and 1',1'',4',4''-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2'',3''][5,6]fullerene-C60 (abbreviated as ICBA).

[0187] Furthermore, examples of n-type semiconductor materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, naphthalene derivatives, anthracene derivatives, coumarin derivatives, rhodamine derivatives, triazine derivatives, and quinone derivatives.

[0188] Examples of p-type semiconductor materials for the active layer include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin(II) phthalocyanine (SnPc), and quinacridone.

[0189] Furthermore, examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, and compounds having an aromatic amine skeleton. In addition, examples of p-type semiconductor materials include naphthalene derivatives, anthracene derivatives, pyrene derivatives, triphenylene derivatives, fluorene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, indrocarbazole derivatives, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, quinacridone derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polythiophene derivatives.

[0190] The HOMO level of electron-donating organic semiconductor materials is preferably shallower (higher) than the HOMO level of electron-accepting organic semiconductor materials. The LUMO level of electron-donating organic semiconductor materials is preferably shallower (higher) than the LUMO level of electron-accepting organic semiconductor materials.

[0191] It is preferable to use spherical fullerenes as electron-accepting organic semiconductor materials and organic semiconductor materials with a near-planar shape as electron-donating organic semiconductor materials. Molecules with similar shapes tend to aggregate, and when molecules of the same type aggregate, their molecular orbital energy levels are close, which can improve carrier transport.

[0192] For example, the active layer is preferably formed by co-depositing an n-type semiconductor and a p-type semiconductor. Alternatively, the active layer may be formed by stacking an n-type semiconductor and a p-type semiconductor.

[0193] The photodetector may further include layers other than the active layer, such as a material with high hole transport properties, a material with high electron transport properties, or a bipolar material (a material with high electron and hole transport properties). Furthermore, it may also further include layers containing a material with high hole injection properties, a hole blocking material, a material with high electron injection properties, an electron blocking material, etc.

[0194] The light-receiving device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-receiving device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0195] For example, polymer compounds such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS), and inorganic compounds such as molybdenum oxide and copper iodide (CuI) can be used as hole transport materials. In addition, inorganic compounds such as zinc oxide (ZnO) can be used as electron transport materials.

[0196] Furthermore, the active layer can use polymer compounds such as Poly[[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c']dithiophene-1,3-diyl]]polymer (abbreviated as PBDB-T) or PBDB-T derivatives, which function as donors. For example, a method of dispersing the acceptor material in PBDB-T or a PBDB-T derivative can be used.

[0197] Furthermore, the active layer may contain a mixture of three or more materials. For example, to broaden the absorption wavelength range, a third material may be mixed with an n-type semiconductor material and a p-type semiconductor material. In this case, the third material may be a low-molecular-weight compound or a high-molecular-weight compound.

[0198] 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, in addition to displaying an image with all of the subpixels of the display device, some subpixels can emit light as a light source, some other subpixels can perform light detection, and the remaining subpixels can display an image.

[0199] A display device according to one aspect of the present invention has a display unit in which light-emitting devices are arranged in a matrix, and an image can be displayed on the display unit. Furthermore, light-receiving devices are arranged in a matrix on the display unit, and the display unit has an image display function, as well as one or both of an imaging function and a sensing function. The display unit can be used as an image sensor or a touch sensor. That is, by detecting light on the display unit, an image can be captured, or the proximity or contact of an object (such as a finger, hand, or pen) can be detected. Moreover, in a display device according to one aspect of the present invention, the light-emitting devices can be used as a light source for a sensor. Therefore, it is not necessary to provide a separate light-receiving unit and light source from the display device, and the number of components in the electronic device can be reduced.

[0200] In one embodiment of the present invention, when an object reflects (or scatters) light emitted by a light-emitting device of the display unit, a light-receiving device can detect the reflected light (or scattered light), thus enabling image capture or touch detection even in dark places.

[0201] When a light-receiving device is used as an image sensor, the display device can capture an image using the light-receiving device. For example, the display device of this embodiment can be used as a scanner.

[0202] For example, an image sensor can be used to acquire biometric data such as fingerprints and palm prints. In other words, a biometric authentication sensor can be built into the display device. By having the display device incorporate the biometric authentication sensor, the number of components in the electronic device can be reduced compared to when a separate biometric authentication sensor is provided, enabling miniaturization and weight reduction of the electronic device.

[0203] Furthermore, when a light-receiving device is used as a touch sensor, the display device can use the light-receiving device to detect the proximity or contact of an object.

[0204] The pixels shown in Figures 7A and 7B have sub-pixels G, B, R, and PS.

[0205] The pixels shown in Figure 7A have a stripe array applied. The pixels shown in Figure 7B have a matrix array applied.

[0206] The pixels shown in Figures 7C and 7D have sub-pixels G, B, R, PS, and IRS.

[0207] Figures 7C and 7D show an example where one pixel is arranged across two rows and three columns. The top row (first row) has three subpixels (subpixel G, subpixel B, and subpixel R). In Figure 7C, the bottom row (second row) has three subpixels (one subpixel PS and two subpixels IRS). On the other hand, in Figure 7D, the bottom row (second row) has two subpixels (one subpixel PS and one subpixel IRS). As shown in Figure 7C, by aligning the arrangement of subpixels in the top and bottom rows, it becomes possible to efficiently remove dust and other debris that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided. Note that the layout of subpixels is not limited to the configuration shown in Figures 7A to 7D.

[0208] 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.

[0209] Sub-pixels PS and IRS each have a light-receiving device. The wavelength of light detected by sub-pixels PS and IRS is not particularly limited.

[0210] In Figure 7C, the two subpixel IRS may each have an independent photodetector, or they may share a single photodetector. In other words, the pixel 110 shown in Figure 7C can be configured to have one photodetector for the subpixel PS and one or two photodetectors for the subpixel IRS.

[0211] The light-receiving area of ​​the sub-pixel PS is smaller than that of the sub-pixel IRS. 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 allows for higher-definition or higher-resolution imaging compared to using sub-pixel IRS. For example, sub-pixel PS can be used to capture images for personal authentication, such as fingerprints, palm prints, irises, pulse patterns (including vein and artery patterns), or faces.

[0212] The light-receiving device in the sub-pixel PS preferably detects visible light, and more preferably detects one or more colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red. Alternatively, the light-receiving device in the sub-pixel PS may also detect infrared light.

[0213] Furthermore, sub-pixel IRS can be used in touch sensors (also called direct touch sensors) or near-touch sensors (also called hover sensors, hover-touch sensors, non-contact sensors, or touchless sensors). Depending on the application, the wavelength of light detected by the sub-pixel IRS can be appropriately determined. For example, it is preferable for the sub-pixel IRS to detect infrared light. This enables touch detection even in dark places.

[0214] Here, the touch sensor or near-touch sensor can detect the proximity or contact of an object (such as a finger, hand, or pen).

[0215] A touch sensor can detect an object by making direct contact with the display device. A 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.

[0216] 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, adjusting within a range of 1 Hz to 240 Hz). In addition, the drive frequency of the touch sensor or near touch sensor may be changed according to the refresh rate. For example, if the refresh rate of the display device is 120 Hz, the drive frequency of the touch sensor or near touch sensor can be set to a frequency higher than 120 Hz (typically 240 Hz). This configuration makes it possible to achieve low power consumption and to increase the response speed of the touch sensor or near touch sensor.

[0217] The display device 100 shown in Figures 7E to 7G has a layer 353 having a light-receiving device, a functional layer 355, and a layer 357 having a light-emitting device between substrate 351 and substrate 359.

[0218] The functional layer 355 includes circuits for driving a light-receiving device and circuits for driving a light-emitting device. The functional layer 355 may be equipped with switches, transistors, capacitors, resistors, wiring, terminals, etc. However, when the light-emitting and light-receiving devices are driven using a passive matrix system, the configuration may omit switches and transistors.

[0219] For example, as shown in Figure 7E, in layer 357 which has a light-emitting device, the light emitted by the light-emitting device is reflected by a finger 352 that is in contact with the display device 100, and the light-receiving device in layer 353 which has a light-receiving device detects the reflected light. This makes it possible to detect that the finger 352 has come into contact with the display device 100. Alternatively, as shown in Figures 7F and 7G, the device may have a function to detect or image objects that are close to (but not in contact with) the display device. Figure 7F shows an example of detecting a person's finger, and Figure 7G shows an example of detecting information around, on the surface of, or inside a person's eye (such as the number of blinks, eyeball movements, and eyelid movements).

[0220] By equipping a single pixel with two types of light-receiving devices, it becomes possible to add two additional functions to the display function, thus enabling the multi-functionality of the display device.

[0221] 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, sub-pixels IRS used in touch sensors or near-touch sensors do not require the same high precision as detection using sub-pixels PS, so it is sufficient to provide them on only some of the pixels of the display device. By reducing the number of sub-pixels IRS in the display device to fewer than the number of sub-pixels PS, the detection speed can be increased.

[0222] As described above, one embodiment of the present invention enables the multi-functionalization of a display device by equipping a single pixel with two types of light-receiving devices, thereby adding two additional functions to the display function. For example, it can realize a high-definition imaging function and a sensing function such as a touch sensor or near-touch sensor. Furthermore, the functionality of the display device can be further increased by combining a pixel equipped with two types of light-receiving devices with a pixel with a different configuration. For example, a pixel having an infrared light-emitting device or various sensor devices can be used.

[0223] [Examples of methods for manufacturing display devices] Next, an example of a method for manufacturing a display device will be explained using Figures 8 to 14. Figures 8A to 8C are top views showing a method for manufacturing a display device. Figures 9A to 9C show the cross-sectional view between the dashed-dotted lines X1 and X2 in Figure 1A, and the cross-sectional view between Y1 and Y2 side by side. Figures 10 to 13 are similar to Figure 9. Figures 14A to 14E show the cross-sectional view between the dashed-dotted lines X1 and X2 in Figure 1A.

[0224] Thin films (insulating films, semiconductor films, and conductive films, etc.) that constitute display devices can be formed using sputtering, chemical vapor deposition (CVD), vacuum deposition, pulsed laser deposition (PLD), ALD, and other methods. CVD methods include plasma-enhanced CVD (PECVD) and thermal CVD. One type of thermal CVD is metal-organic CVD (MOCVD).

[0225] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife coating, slit coating, roll coating, curtain coating, and knife coating.

[0226] In particular, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet can be used to fabricate light-emitting devices. Examples of vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, as well as chemical vapor deposition (CVD). Functional layers included in the EL layer (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, etc.) can be formed by vapor deposition (vacuum deposition, etc.), coating methods (dip coating, die coating, bar coating, spin coating, spray coating, etc.), and printing methods (inkjet, screen printing, offset printing, flexographic printing, gravure, or microcontact printing, etc.).

[0227] Furthermore, when processing the thin film that constitutes the display device, photolithography or the like can be used. Alternatively, the thin film may be processed by nanoimprint lithography, sandblasting, lift-off lithography, or the like. In addition, island-shaped thin films may be directly formed by a film deposition method using a shielding mask such as a metal mask.

[0228] There are two main methods of photolithography. One method involves forming a resist mask on the thin film to be processed, then processing the thin film by etching or other means, and removing the resist mask. The other method involves forming a photosensitive thin film, then exposing and developing it to process the thin film into the desired shape.

[0229] 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 a beam such as an electron beam.

[0230] For etching thin films, methods such as dry etching, wet etching, and sandblasting can be used.

[0231] First, as shown in Figure 9A, a conductive film 111 is formed on the layer 101 containing the transistor.

[0232] Then, a first light-emitting unit 181A, a charge generation layer 182A, and a second light-emitting unit 183A are formed on the conductive film 111 in this order, a first sacrificial layer 118A is formed on the second light-emitting unit 183A, and a second sacrificial layer 119A is formed on the first sacrificial layer 118A.

[0233] As shown in Figure 9A, in the cross-sectional view between Y1 and Y2, the ends of the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A on the connection portion 140 side are located inward from the end of the first sacrificial layer 118A. For example, by using a mask for defining the film deposition area (also called an area mask or rough metal mask, to distinguish it from a fine metal mask), the areas to be film-deposited by the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A, and the first sacrificial layer 118A and the second sacrificial layer 119A can be changed. In one embodiment of the present invention, a light-emitting device is formed using a resist mask, but by combining it with an area mask as described above, a light-emitting device can be manufactured in a relatively simple process.

[0234] The conductive film 111 is a layer that will later be processed to become the pixel electrodes 111a, 111b, 111c, and the conductive layer 123. Therefore, the configurations applicable to the pixel electrodes described above can be applied to the conductive film 111. For example, sputtering or vacuum deposition can be used to form the conductive film 111.

[0235] The first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A are layers that later become the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a, respectively. Therefore, the configurations applicable to the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a described above can be applied to each of them. The first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating. It is preferable to form each layer using vapor deposition. In film formation using vapor deposition, a premixed material may be used. In this specification, a premixed material is a composite material obtained by pre-combining or mixing multiple materials.

[0236] The first sacrificial layer 118A and the second sacrificial layer 119A use films that have high resistance to processing conditions for the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A, as well as the first light-emitting unit 181B, the charge generation layer 182B, the second light-emitting unit 183B, the first light-emitting unit 181C, the charge generation layer 182C, and the second light-emitting unit 183C formed in a later process. Specifically, films with a high selectivity for etching with various EL layers are used.

[0237] For the formation of the first sacrificial layer 118A and the second sacrificial layer 119A, for example, sputtering, ALD (including thermal ALD and PEALD), CVD, or vacuum deposition can be used. It is preferable that the first sacrificial layer 118A, which is formed in contact with the EL layer, is formed using a method that causes less damage to the EL layer than the second sacrificial layer 119A. For example, it is preferable to form the first sacrificial layer 118A using ALD or vacuum deposition rather than sputtering. Furthermore, the first sacrificial layer 118A and the second sacrificial layer 119A are formed at a temperature lower than the heat resistance temperature of the EL layer (typically 200°C or lower, preferably 100°C or lower, and more preferably 80°C or lower).

[0238] It is preferable to use films that can be removed by wet etching for the first sacrificial layer 118A and the second sacrificial layer 119A. By using wet etching, the damage inflicted on the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A during processing of the first sacrificial layer 118A and the second sacrificial layer 119A can be reduced compared to when dry etching is used.

[0239] Furthermore, it is preferable to use a film for the first sacrificial layer 118A that has a high etching selectivity ratio with the second sacrificial layer 119A.

[0240] In the manufacturing process of the display device according to this embodiment, it is desirable that each layer constituting the EL layer (hole injection layer, hole transport layer, light-emitting layer, and electron transport layer, etc.) is difficult to process, and that the various sacrificial layers are difficult to process during the manufacturing process of each layer constituting the EL layer. It is desirable to select the material and manufacturing method of the sacrificial layer and the manufacturing method of the EL layer taking these factors into consideration.

[0241] In this embodiment, an example is shown in which the sacrificial layer is formed with a two-layer structure consisting of a first sacrificial layer and a second sacrificial layer. However, the sacrificial layer may be a single-layer structure or a laminated structure of three or more layers.

[0242] For the first sacrificial layer 118A and the second sacrificial layer 119A, for example, inorganic films such as metal films, alloy films, metal oxide films, semiconductor films, and inorganic insulating films can be used, respectively.

[0243] The first sacrificial layer 118A and the second sacrificial layer 119A can be made of metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metallic materials. In particular, it is preferable to use low-melting-point materials such as aluminum or silver. It is preferable to use a metallic material capable of shielding ultraviolet light in one or both of the first sacrificial layer 118A and the second sacrificial layer 119A, as this can suppress irradiation of the EL layer with ultraviolet light and thus suppress deterioration of the EL layer.

[0244] Furthermore, metal oxides such as In-Ga-Zn oxide can be used for the first sacrificial layer 118A and the second sacrificial layer 119A. For example, an In-Ga-Zn oxide film can be formed as the first sacrificial layer 118A or the second sacrificial layer 119A using a sputtering method. In addition, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc. can be used. Alternatively, indium tin oxide containing silicon can also be used.

[0245] In addition, element M (where M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) may be used instead of gallium.

[0246] Furthermore, various inorganic insulating films that can be used for protective layers 131 and 132 can be used as the first sacrificial layer 118A and the second sacrificial layer 119A. In particular, oxide insulating films are preferred because they have higher adhesion to the EL layer compared to nitride insulating films. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used for the first sacrificial layer 118A and the second sacrificial layer 119A. For example, an aluminum oxide film can be formed as the first sacrificial layer 118A or the second sacrificial layer 119A using the ALD method. Using the ALD method is preferable because it reduces damage to the substrate (especially the EL layer).

[0247] For example, an inorganic insulating film (e.g., an aluminum oxide film) formed using the ALD method can be used as the first sacrificial layer 118A, and an In-Ga-Zn oxide film formed using the sputtering method can be used as the second sacrificial layer 119A. Alternatively, an inorganic insulating film (e.g., an aluminum oxide film) formed using the ALD method can be used as the first sacrificial layer 118A, and an aluminum film or tungsten film formed using the sputtering method can be used as the second sacrificial layer 119A.

[0248] As the first sacrificial layer 118A and the second sacrificial layer 119A, materials that can be dissolved in a solvent that is chemically stable to the film located at least at the top of the second light-emitting unit 183A may be used. In particular, materials that are soluble in water or alcohol can be suitably used for the first sacrificial layer 118A or the second sacrificial layer 119A. When forming such a film, it is preferable to coat the material by a wet deposition method while it is dissolved in a solvent such as water or alcohol, and then perform a heat treatment to evaporate the solvent. At this time, performing the heat treatment under a reduced pressure atmosphere is preferable because it is possible to remove the solvent at a low temperature and in a short time, thereby reducing thermal damage to the EL layer.

[0249] The first sacrificial layer 118A and the second sacrificial layer 119A may be formed using wet film formation methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating.

[0250] The first sacrificial layer 118A and the second sacrificial layer 119A may be made of organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin.

[0251] Next, as shown in Figure 9B, a resist mask 190a is formed on the second sacrificial layer 119A. The resist mask can be formed by applying a photosensitive resin (photoresist), exposing it to light, and developing it.

[0252] The resist mask may be made using either a positive-type resist material or a negative-type resist material.

[0253] As shown in Figure 8A, the resist mask 190a is provided in a position that overlaps with the region that will later become the subpixel 110a. Preferably, the resist mask 190a has one island-shaped pattern for each subpixel 110a. Alternatively, the resist mask 190a may have one band-shaped pattern for multiple subpixels 110a arranged in a row (arranged in the Y direction in Figure 8A).

[0254] Furthermore, it is preferable to also provide the resist mask 190a in a position that overlaps with the area that will later become the connection portion 140. This helps to prevent damage to the area of ​​the conductive film 111 that will later become the conductive layer 123 during the manufacturing process of the display device.

[0255] Next, as shown in Figure 9C, a resist mask 190a is used to remove a portion of the second sacrificial layer 119A, thereby forming a second sacrificial layer 119a. The second sacrificial layer 119a remains in the region that will later become the subpixel 110a and the region that will later become the connection portion 140.

[0256] When etching the second sacrificial layer 119A, it is preferable to use etching conditions with a high selectivity ratio so that the first sacrificial layer 118A is not removed by the etching. Furthermore, since the EL layer is not exposed during the processing of the second sacrificial layer 119A, there is a wider range of processing methods to choose from than for the processing of the first sacrificial layer 118A. Specifically, when processing the second sacrificial layer 119A, even if an etching gas containing oxygen is used, the deterioration of the EL layer can be further suppressed.

[0257] Subsequently, the resist mask 190a is removed. For example, the resist mask 190a can be removed by ashing using oxygen plasma. Alternatively, oxygen gas and noble gases (also called rare gases) such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He may be used. Alternatively, the resist mask 190a may be removed by wet etching. In this case, since the first sacrificial layer 118A is located on the outermost surface and the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A are not exposed, damage to the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A can be suppressed during the resist mask 190a removal process. Furthermore, the range of selectable methods for removing the resist mask 190a can be broadened.

[0258] Next, as shown in Figure 10A, the second sacrificial layer 119a is used as a hard mask to remove a portion of the first sacrificial layer 118A and form the first sacrificial layer 118a.

[0259] The first sacrificial layer 118A and the second sacrificial layer 119A can be processed by wet etching or dry etching, respectively. It is preferable to process the first sacrificial layer 118A and the second sacrificial layer 119A by anisotropic etching.

[0260] By using the wet etching method, damage to the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A during processing of the first sacrificial layer 118A and the second sacrificial layer 119A can be reduced compared to the dry etching method. When using the wet etching method, it is preferable to use chemical solutions such as a developer, an aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0261] Furthermore, when using the dry etching method, the degradation of the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A can be suppressed by not using an oxygen-containing gas as the etching gas. When using the dry etching method, it is preferable to use a gas containing noble gases (also called rare gases) such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He as the etching gas.

[0262] For example, when an aluminum oxide film formed using the ALD method is used as the first sacrificial layer 118A, the first sacrificial layer 118A can be processed by dry etching using CHF3 and He. Also, when an In-Ga-Zn oxide film formed using the sputtering method is used as the second sacrificial layer 119A, the second sacrificial layer 119A can be processed by wet etching using diluted phosphoric acid. Alternatively, it may be processed by dry etching using CH4 and Ar. Alternatively, the second sacrificial layer 119A can be processed by wet etching using diluted phosphoric acid. Furthermore, when a tungsten film formed using the sputtering method is used as the second sacrificial layer 119A, the second sacrificial layer 119A can be processed by dry etching using CF4 and O2, or CF4, Cl2, and O2.

[0263] Next, as shown in Figure 10B, the second sacrificial layer 119a and the first sacrificial layer 118a are used as a hard mask to remove a portion of the first light-emitting unit 181A, a portion of the charge generation layer 182A, and a portion of the second light-emitting unit 183A, thereby forming the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a.

[0264] As a result, as shown in FIG. 10B, in the region corresponding to the sub-pixel 110a, a stacked structure of the first light-emitting unit 181a, the charge generation layer 182a, the second light-emitting unit 183a, the first sacrificial layer 118a, and the second sacrificial layer 119a remains on the conductive film 111. The stacked structure of the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a is also referred to as the first layer 113a. Further, in the region corresponding to the connection portion 140, a stacked structure of the first sacrificial layer 118a and the second sacrificial layer 119a remains on the conductive film 111.

[0265] Through the above steps, the regions of the first light-emitting unit 181A, the charge generation layer 182A, the second light-emitting unit 183A, the first sacrificial layer 118A, and the second sacrificial layer 119A that do not overlap with the resist mask 190a can be removed.

[0266] Note that a part of the first light-emitting unit 181A, a part of the charge generation layer 182A, and a part of the second light-emitting unit 183A may be removed using the resist mask 190a. Thereafter, the resist mask 190a may be removed.

[0267] Alternatively, the process may proceed to the next step without removing the resist mask 190a. In this case, when processing the conductive film 111 in a later step, not only the sacrificial layer but also the resist mask can be used as a mask. By processing the conductive film 111 using the resist masks 190a, 190b, and 190c, the processing of the conductive film 111 may be easier than when only the sacrificial layer is used as a hard mask. For example, the range of selection of the processing conditions of the conductive film 111, the material of the sacrificial layer, or the material of the conductive film can be widened.

[0268] The processing of the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A is preferably performed by anisotropic etching. In particular, anisotropic dry etching is preferred. Alternatively, wet etching may be used.

[0269] When using the dry etching method, the degradation of the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A can be suppressed by not using an oxygen-containing gas as the etching gas.

[0270] Furthermore, an etching gas containing oxygen may be used. Including oxygen in the etching gas can increase the etching rate. Therefore, etching can be performed under low power conditions while maintaining a sufficiently fast etching rate. As a result, damage to the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A can be suppressed. In addition, problems such as the adhesion of reaction products generated during etching can be suppressed.

[0271] When using the dry etching method, it is preferable to use an etching gas containing one or more noble gases (also called rare gases) such as H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He, Ar. Alternatively, it is preferable to use an etching gas containing one or more of these and oxygen. Or, oxygen gas may be used as the etching gas. Specifically, for example, a gas containing H2 and Ar, or a gas containing CF4 and He, can be used as the etching gas. Also, for example, a gas containing CF4, He, and oxygen can be used as the etching gas.

[0272] Next, as shown in Figure 10C, the first light-emitting unit 181B, the charge generation layer 182B, and the second light-emitting unit 183B are formed in this order on the second sacrificial layer 119a and the conductive film 111, the first sacrificial layer 118B is formed on the second light-emitting unit 183B, and the second sacrificial layer 119B is formed on the first sacrificial layer 118B.

[0273] As shown in Figure 10C, in the cross-sectional view between Y1 and Y2, the ends of the connection portion 140 of the first light-emitting unit 181B, the charge generation layer 182B, and the second light-emitting unit 183B are located inward from the end of the first sacrificial layer 118B.

[0274] The first light-emitting unit 181B, the charge generation layer 182B, and the second light-emitting unit 183B are layers that later become the first light-emitting unit 181b, the charge generation layer 182b, and the second light-emitting unit 183b, respectively. The first light-emitting unit 181b and the second light-emitting unit 183b emit light of a different color from the first light-emitting unit 181a and the second light-emitting unit 183a, respectively. The configurations and materials applicable to the first light-emitting unit 181b, the charge generation layer 182b, and the second light-emitting unit 183b are the same as those for the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a, respectively. The first light-emitting unit 181B, the charge generation layer 182B, and the second light-emitting unit 183B can each be formed using the same method as the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A.

[0275] The first sacrificial layer 118B can be formed using a material applicable to the first sacrificial layer 118A. The second sacrificial layer 119B can be formed using a material applicable to the second sacrificial layer 119A.

[0276] Next, as shown in Figure 10C, a resist mask 190b is formed on the second sacrificial layer 119B.

[0277] As shown in Figure 8B, the resist mask 190b is provided in a position that overlaps with the region that will later become the subpixel 110b. Preferably, the resist mask 190b has one island-shaped pattern for each subpixel 110b. Alternatively, the resist mask 190b may have one strip-shaped pattern for multiple subpixels 110b arranged in a row.

[0278] The resist mask 190b may also be provided in a position that overlaps with the area that will later become the connection portion 140.

[0279] Next, a resist mask 190b is used to remove a portion of the second sacrificial layer 119B, thereby forming the second sacrificial layer 119b. The second sacrificial layer 119b remains in the region that will later become the subpixel 110b.

[0280] Subsequently, the resist mask 190b is removed. Then, the second sacrificial layer 119b is used as a hard mask to remove a portion of the first sacrificial layer 118B and form the first sacrificial layer 118b.

[0281] Then, as shown in Figure 11A, the second sacrificial layer 119b and the first sacrificial layer 118b are used as a hard mask to remove a portion of the first light-emitting unit 181B, a portion of the charge generation layer 182B, and a portion of the second light-emitting unit 183B, thereby forming the first light-emitting unit 181b, the charge generation layer 182b, and the second light-emitting unit 183b.

[0282] As a result, as shown in Figure 11A, in the region corresponding to the sub-pixel 110b, the stacked structure of the first light-emitting unit 181b, the charge generation layer 182b, the second light-emitting unit 183b, the first sacrificial layer 118b, and the second sacrificial layer 119b remains on the conductive film 111. The stacked structure of the first light-emitting unit 181b, the charge generation layer 182b, and the second light-emitting unit 183b is also referred to as the second layer 113b. Furthermore, in the region corresponding to the connection portion 140, the stacked structure of the first sacrificial layer 118a and the second sacrificial layer 119a remains on the conductive film 111.

[0283] By following the above steps, the regions of the first light-emitting unit 181B, the charge generation layer 182B, the second light-emitting unit 183B, the first sacrificial layer 118B, and the second sacrificial layer 119B that do not overlap with the resist mask 190b can be removed. For processing these layers, methods applicable to processing the first light-emitting unit 181A, the charge generation layer 182A, the second light-emitting unit 183A, the first sacrificial layer 118A, and the second sacrificial layer 119A can be used.

[0284] Next, as shown in FIG. 11B, a first light-emitting unit 181C, a charge generation layer 182C, and a second light-emitting unit 183C are formed in this order on the second sacrificial layer 119a, the second sacrificial layer 119b, and the conductive film 111. A first sacrificial layer 118C is formed on the second light-emitting unit 183C, and a second sacrificial layer 119C is formed on the first sacrificial layer 118C.

[0285] As shown in FIG. 11B, in the cross-sectional view between Y1 - Y2, the end portions of the first light-emitting unit 181C, the charge generation layer 182C, and the second light-emitting unit 183C on the connection portion 140 side are located inside the end portion of the first sacrificial layer 118C.

[0286] The first light-emitting unit 181C, the charge generation layer 182C, and the second light-emitting unit 183C are, respectively, layers that will later become the first light-emitting unit 181c, the charge generation layer 182c, and the second light-emitting unit 183c. The first light-emitting unit 181c and the second light-emitting unit 183c emit light of different colors from the first light-emitting units 181a, 181b, and the second light-emitting units 183a, 183b, respectively. The configurations and materials applicable to the first light-emitting unit 181c, the charge generation layer 182c, and the second light-emitting unit 183c are the same as those of the first light-emitting unit 181a, the charge generation layer 182a, and the second light-emitting unit 183a, respectively. The first light-emitting unit 181C, the charge generation layer 182C, and the second light-emitting unit 183C can be formed by the same method as the first light-emitting unit 181A, the charge generation layer 182A, and the second light-emitting unit 183A, respectively.

[0287] The first sacrificial layer 118C can be formed using a material applicable to the first sacrificial layer 118A. The second sacrificial layer 119C can be formed using a material applicable to the second sacrificial layer 119A.

[0288] Next, as shown in FIG. 11B, a resist mask 190c is formed on the second sacrificial layer 119C.

[0289] As shown in Figure 8C, the resist mask 190c is provided in a position that overlaps with the region that will later become the subpixel 110c. Preferably, the resist mask 190c has one island-shaped pattern for each subpixel 110c. Alternatively, the resist mask 190c may have one strip-shaped pattern for multiple subpixels 110c arranged in a row.

[0290] The resist mask 190c may also be provided in a position that overlaps with the area that will later become the connection portion 140.

[0291] Next, a resist mask 190c is used to remove a portion of the second sacrificial layer 119C, thereby forming a second sacrificial layer 119c. The second sacrificial layer 119c remains in the region that will later become the subpixel 110c.

[0292] Subsequently, the resist mask 190c is removed. Then, the second sacrificial layer 119c is used as a hard mask to remove a portion of the first sacrificial layer 118C and form the first sacrificial layer 118c.

[0293] Then, as shown in Figure 11C, the second sacrificial layer 119c and the first sacrificial layer 118c are used as a hard mask to remove a portion of the first light-emitting unit 181C, a portion of the charge generation layer 182C, and a portion of the second light-emitting unit 183C, thereby forming the first light-emitting unit 181c, the charge generation layer 182c, and the second light-emitting unit 183c.

[0294] As a result, as shown in Figure 11C, in the region corresponding to the sub-pixel 110c, the stacked structure of the first light-emitting unit 181c, the charge generation layer 182c, the second light-emitting unit 183c, the first sacrificial layer 118c, and the second sacrificial layer 119c remains on the conductive film 111. The stacked structure of the first light-emitting unit 181c, the charge generation layer 182c, and the second light-emitting unit 183c is also referred to as the third layer 113c. Furthermore, in the region corresponding to the connection portion 140, the stacked structure of the first sacrificial layer 118a and the second sacrificial layer 119a remains on the conductive film 111.

[0295] By following the above steps, the regions of the first light-emitting unit 181C, the charge generation layer 182C, the second light-emitting unit 183C, the first sacrificial layer 118C, and the second sacrificial layer 119C that do not overlap with the resist mask 190c can be removed. For processing these layers, methods applicable to processing the first light-emitting unit 181A, the charge generation layer 182A, the second light-emitting unit 183A, the first sacrificial layer 118A, and the second sacrificial layer 119A can be used.

[0296] Furthermore, it is preferable that the sides of each light-emitting unit and charge-generating layer are perpendicular or approximately perpendicular to the surface to be formed. For example, it is preferable that the angle between the surface to be formed and these sides be 60 degrees or more and 90 degrees or less.

[0297] Next, as shown in Figure 12A, the conductive film 111 is processed using the first sacrificial layers 118a, 118b, 118c and the second sacrificial layers 119a, 119b, 119c as a hard mask to form the pixel electrodes 111a, 111b, 111c and the conductive layer 123.

[0298] Furthermore, before processing the conductive film 111, sidewalls may be formed to cover the sides of the first layer 113a, the second layer 113b, and the third layer 113c. This makes it possible to suppress damage to the first layer 113a, the second layer 113b, and the third layer 113c during the processing of the conductive film 111.

[0299] During the processing of the conductive film 111, a portion of the layer 101 containing the transistor (specifically, the insulating layer located on the outermost surface) may be processed, forming a recess. In the following explanation, we will use the case where a recess is provided in the layer 101 containing the transistor as an example, but a recess is not required.

[0300] In order to form the conductive layer 123, it is preferable that one of the first sacrificial layers 118a, 118b, and 118c and one of the second sacrificial layers 119a, 119b, and 119c are provided at the connection portion 140. Alternatively, two or all of the first sacrificial layers 118a, 118b, and 118c and two or all of the second sacrificial layers 119a, 119b, and 119c may be provided at the connection portion 140. By providing the sacrificial layers at the connection portion 140, it is possible to suppress damage to the region of the conductive film 111 that will become the conductive layer 123 during the manufacturing process of the display device. Therefore, it is preferable to form the first sacrificial layer 118a and the second sacrificial layer 119a, which have the earliest manufacturing process.

[0301] The conductive film 111 can be processed by wet etching or dry etching. It is preferable to process the conductive film 111 by anisotropic etching.

[0302] Next, as shown in Figure 12B, an insulating film 125A is formed to cover the pixel electrodes 111a, 111b, 111c, the first layer 113a, the second layer 113b, the third layer 113c, the first sacrificial layers 118a, 118b, 118c, and the second sacrificial layers 119a, 119b, 119c, and an insulating film 125B is formed on top of the insulating film 125A.

[0303] For insulating film 125A and insulating film 125B, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used, respectively. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, magnesium oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxidative nitride insulating films include silicon oxidative nitride films and aluminum oxidative nitride films. Examples of nitride oxide insulating films include silicon nitride film and aluminum nitride film.

[0304] It is preferable that insulating film 125A and insulating film 125B be formed using a method that causes minimal damage to the EL layer. In particular, since insulating film 125A is formed in contact with the side surface of the EL layer, it is preferable that it be formed using a method that causes less damage to the EL layer than insulating film 125B. Furthermore, insulating film 125A and insulating film 125B are formed at a temperature lower than the heat resistance temperature of the EL layer (typically 200°C or lower, preferably 100°C or lower, and even more preferably 80°C or lower). For example, an aluminum oxide film can be formed as insulating film 125A using the ALD method. The ALD method is preferable because it can reduce film formation damage and allow for the formation of a film with high coverage. Also, for example, a silicon oxide nitride film or silicon nitride film can be formed as insulating film 125B using the sputtering method, CVD method, or PECVD method. These methods have a faster film formation rate compared to the ALD method, thus increasing productivity. Furthermore, it is preferable that insulating film 125B is a thicker film than insulating film 125A.

[0305] Furthermore, it is preferable that one or both of the insulating film 125A and insulating film 125B function as a barrier insulating film against at least one of water and oxygen. Alternatively, it is preferable that one or both of the insulating film 125A and insulating film 125B have a function to suppress the diffusion of at least one of water and oxygen. Alternatively, it is preferable that one or both of the insulating film 125A and insulating film 125B have a function to capture or fix (also called gettering) at least one of water and oxygen.

[0306] In this specification, a barrier insulating film refers to an insulating film that has barrier properties. In this specification, barrier properties refer to the function of suppressing the diffusion of the corresponding substance (also called low permeability), or the function of capturing or fixing the corresponding substance (also called gettering).

[0307] The insulating film 125A and the insulating film 125B, or both, have the functions of a barrier insulating film or gettering function as described above, thereby suppressing the intrusion of impurities (typically water or oxygen) that could diffuse from the outside into each light-emitting device. This configuration makes it possible to provide a display device with excellent reliability.

[0308] Next, as shown in Figure 12C, side walls 125a and 125b are formed by processing the insulating film 125A and insulating film 125B. Side wall 125b is formed so as to be in contact with the upper and side surfaces of side wall 125a. Side walls 125a and 125b are provided so as to cover the sides of the pixel electrodes 111a, 111b, and 111c. This prevents the light-emitting device from short-circuiting due to contact between the later-formed film (the film constituting the EL layer, or the common electrode) and the pixel electrodes 111a, 111b, and 111c. Furthermore, it is preferable that side walls 125a and 125b are provided so as to cover the sides of the first layer 113a, the second layer 113b, and the third layer 113c. This prevents the later-formed film from coming into contact with the sides of these layers, thereby preventing the light-emitting device from short-circuiting. Furthermore, damage to the first layer 113a, the second layer 113b, and the third layer 113c in subsequent processes can be suppressed.

[0309] In particular, it is preferable that a recess is provided in a part of the layer 101 containing the transistor (specifically, the insulating layer located on the outermost surface), as this makes it possible to cover the entire sides of the pixel electrodes 111a, 111b, and 111c with the side walls 125a and 125b.

[0310] The insulating film 125A and insulating film 125B are preferably processed by a dry etching method. The processing of insulating film 125A and insulating film 125B is preferably carried out by anisotropic etching. The insulating film 125A and insulating film 125B can be processed using the etching gas that can be used when processing the first sacrificial layer 118A and the second sacrificial layer 119A. Furthermore, since the EL layer is not exposed when processing insulating film 125A and insulating film 125B, there is a wider range of processing method options than when processing the first sacrificial layer 118A. Specifically, even when using an etching gas containing oxygen when processing insulating film 125A or insulating film 125B, the degradation of the EL layer can be further suppressed.

[0311] The shape of the end of the side wall 125b can be rounded. For example, when forming the insulating film 125B, if a dry etching method is used and the upper part of the insulating film 125B is etched by anisotropic etching, the end of the side wall 125b will be rounded as shown in Figure 12C. Rounding the shape of the end of the side wall 125b is preferable because it improves the coverage of the fifth layer 114 or common electrode 115 that is formed later. As shown in Figure 12B, it is sometimes easier to make the end of the side wall 125b rounded by making the thickness of the insulating film 125B thicker than the thickness of the insulating film 125A.

[0312] Here, we show an example where the side walls are formed with a two-layer structure, but the side walls may also be a single-layer structure or a laminated structure of three or more layers.

[0313] Next, as shown in Figure 13A, the first sacrificial layers 118a, 118b, 118c and the second sacrificial layers 119a, 119b, 119c are removed. As a result, the first layer 113a is exposed on the pixel electrode 111a, the second layer 113b is exposed on the pixel electrode 111b, the third layer 113c is exposed on the pixel electrode 111c, and the conductive layer 123 is exposed at the connection portion 140.

[0314] The same method as the sacrificial layer processing method can be used for the sacrificial layer removal process. In particular, by using a wet etching method, the damage inflicted on the first layer 113a, the second layer 113b, and the third layer 113c when removing the first and second sacrificial layers can be reduced compared to when using a dry etching method.

[0315] The first sacrificial layer and the second sacrificial layer may be removed in separate processes or in the same process.

[0316] Alternatively, either the first sacrificial layer or the second sacrificial layer, or both, may be removed by dissolving them in a solvent such as water or alcohol. Examples of alcohols include ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0317] After removing the first and second sacrificial layers, a drying treatment may be performed to remove water contained in the EL layer and water adsorbed on the surface of the EL layer. For example, a heat treatment can be performed in an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 120°C. A reduced pressure atmosphere is preferable because it allows drying at a lower temperature.

[0318] Next, as shown in Figure 13B, a fifth layer 114 is formed so as to cover the side walls 125a, 125b, the first layer 113a, the second layer 113b, and the third layer 113c. As shown in Figure 13B, in the cross-sectional view between Y1 and Y2, the end of the fifth layer 114 on the connection portion 140 side is located inside the connection portion 140, and the conductive layer 123 remains exposed. Note that, as shown in Figure 13C, depending on the conductivity of the fifth layer 114, the fifth layer 114 may also be provided at the connection portion 140.

[0319] The materials that can be used as the fifth layer 114 are as described above. The fifth layer 114 can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating. The fifth layer 114 may also be formed using a premixed material.

[0320] The fifth layer 114 is provided so as to cover the upper surfaces of the side wall 125a, the first layer 113a, the second layer 113b, and the third layer 113c, as well as the upper and side surfaces of the side wall 125b. If the fifth layer 114 has high conductivity, there is a risk of the light-emitting device short-circuiting if the fifth layer 114 comes into contact with any of the pixel electrodes 111a, 111b, or 111c. However, in a display device according to one aspect of the present invention, since the side walls 125a and 125b cover the first layer 113a, the second layer 113b, the third layer 113c, and the side surfaces of the pixel electrodes 111a, 111b, and 111c, it is possible to suppress contact between the highly conductive fifth layer 114 and these layers, thereby suppressing a short circuit in the light-emitting device. This improves the reliability of the light-emitting device.

[0321] Then, as shown in Figure 13B, a common electrode 115 is formed on the fifth layer 114 and the conductive layer 123.

[0322] When depositing the common electrode 115, a mask may be used to define the deposition area. Alternatively, the common electrode 115 may be processed after deposition using a resist mask or the like, without using such a mask during deposition.

[0323] The materials that can be used as the common electrode 115 are as described above. For the formation of the common electrode 115, for example, sputtering or vacuum deposition can be used. Alternatively, a film formed by deposition and a film formed by sputtering may be laminated together.

[0324] As shown in Figure 14A, a gap 134 may be formed in the region between the sides of two opposing EL layers (between the side walls 125b) and in the recess of the layer 101 containing the transistor. Specifically, in Figure 14A, a gap 134 is provided surrounded by the layer 101 containing the transistor, the side walls 125a and 125b, and the fifth layer 114.

[0325] As described above, voids 134 may exist in the region between the sides of two opposing EL layers and in the recesses of layer 101 containing the transistor. Depending on the distance between adjacent EL layers, the thickness of the fifth layer 114, the thickness of the common electrode 115, and the thickness of the protective layer 131, such voids may not be formed. In this case, the region between the sides of two opposing EL layers and the recesses of layer 101 containing the transistor will be filled with at least one of the fifth layer 114, the common electrode 115, and the protective layer 131. Alternatively, an insulating material may be filled into the region that could become a void.

[0326] The voids contain one or more of the following: air, nitrogen, oxygen, carbon dioxide, and Group 18 elements (typically helium, neon, argon, xenon, krypton, etc.). The voids may also contain gases used during film formation, such as the fifth layer 114. For example, when forming the fifth layer 114 by vacuum deposition, the voids may be in a reduced-pressure atmosphere. If gases are present in the voids, their identification can be performed using methods such as gas chromatography.

[0327] Furthermore, if the refractive index of the air gap is lower than that of the fifth layer 114, the common electrode 115, or the protective layer 131, the light emitted from the first layer 113a, the second layer 113b, or the third layer 113c will be reflected at the interface between the fifth layer 114, the common electrode 115, or the protective layer 131 and the air gap. This suppresses the incidence of light emitted from the first layer 113a, the second layer 113b, or the third layer 113c onto adjacent pixels (or sub-pixels). This suppresses the mixing of light of different colors, thereby improving the display quality of the display device.

[0328] Furthermore, an insulating material may be filled into any gaps 134. The insulating material can be an organic insulating material, an inorganic insulating material, or both. The insulating material can be at least one of a solid, a gel-like substance, or a liquid substance.

[0329] Examples of organic insulating materials include acrylic resins, epoxy resins, polyimide resins, polyamide resins, polyimidoamide resins, polysiloxane resins, benzocyclobutene resins, and phenolic resins. Furthermore, various resins suitable for the resin layer 122 may also be used.

[0330] Examples of inorganic insulating materials include oxide insulating materials, nitride insulating materials, oxidogenic nitride insulating materials, and nitride oxide insulating materials. In addition, insulating materials that can be used for the protective layers 131 and 132 may be used.

[0331] Furthermore, as shown in Figure 14B, the fifth layer 114 may be omitted, and the common electrode 115 may be formed to cover the side walls 125a, 125b, the first layer 113a, the second layer 113b, and the third layer 113c. In other words, in light-emitting devices that emit light of different colors, all the layers constituting the EL layer may be manufactured separately. In this case, the EL layers of each light-emitting device are all formed in an island shape.

[0332] In this case, there is a risk of the light-emitting device short-circuiting if the common electrode 115 comes into contact with any of the pixel electrodes 111a, 111b, or 111c. However, in a display device according to one aspect of the present invention, the side walls 125a and 125b cover the first layer 113a, the second layer 113b, the third layer 113c, and the sides of the pixel electrodes 111a, 111b, and 111c, thereby suppressing contact between the common electrode 115 and these layers, and thus preventing a short circuit in the light-emitting device. This improves the reliability of the light-emitting device.

[0333] Figure 14B shows an example in which the common electrode 115 is embedded in the region between the light-emitting devices (between the side walls 125b) and into the recess of the layer 101 containing the transistor. Alternatively, a gap 134 may be provided, as shown in Figure 14A.

[0334] Thus, the shape of the layer formed after the side walls 125a and 125b are varied and not particularly limited, depending on the material, film deposition method, and film thickness. One embodiment of the present invention is a display device in which short circuits of the light-emitting device are suppressed by having side walls 125a and 125b. Therefore, the range of selection for the material, film deposition method, and film thickness of the layer formed after the side walls 125a and 125b can be broadened.

[0335] Furthermore, as shown in Figure 14C, a single-layer side wall 125 may be provided. The material and forming method for the side wall 125 can be the same as those applicable to side walls 125a and 125b.

[0336] Furthermore, as shown in Figure 14D, during the processing of the insulating film 125A, a portion of the layer 101 containing the transistor (specifically, the insulating layer located on the outermost surface) may be processed, and a recess may be formed.

[0337] Furthermore, as shown in Figure 14E, if a portion of the layer 101 containing the transistor (specifically, the insulating layer located on the outermost surface) is not processed during the processing of the conductive film 111, a recess may not be provided in the layer 101 containing the transistor.

[0338] Subsequently, a protective layer 131 is formed on the common electrode 115, and a protective layer 132 is formed on the protective layer 131. Furthermore, by using a resin layer 122 to bond the substrate 120 onto the protective layer 132, the display device 100 shown in Figure 1B can be manufactured.

[0339] The materials and film formation methods that can be used for protective layers 131 and 132 are as described above. Examples of film formation methods for protective layers 131 and 132 include vacuum deposition, sputtering, CVD, and ALD. Protective layers 131 and 132 may be formed using different film formation methods. Furthermore, protective layers 131 and 132 may each be a single-layer structure or a multilayer structure.

[0340] As described above, in the manufacturing method of the display device of this embodiment, the island-shaped EL layer is formed not using a fine metal mask, but by processing after the EL layer has been deposited on one surface. Therefore, the island-shaped EL layer can be formed with a uniform thickness. This makes it possible to realize a high-definition display device or a display device with a high aperture ratio.

[0341] The first, second, and third layers constituting each color of light-emitting device are formed in separate processes. Therefore, each EL layer can be fabricated with a configuration (material, film thickness, etc.) suitable for each color of light-emitting device. This makes it possible to produce light-emitting devices with excellent characteristics.

[0342] A display device according to one aspect of the present invention has side walls covering the sides of the pixel electrodes, the light-emitting layer, and the carrier transport layer. In the manufacturing process of the display device, the EL layer is processed with the light-emitting layer and the carrier transport layer stacked, so the display device has a configuration that reduces damage to the light-emitting layer. Furthermore, the side walls prevent contact between the pixel electrodes and the carrier injection layer or common electrodes, thereby preventing short circuits in the light-emitting device.

[0343] This embodiment can be combined with other embodiments as appropriate. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, these configuration examples can be combined as appropriate.

[0344] (Embodiment 2) In this embodiment, an example of the configuration of a light-emitting device that can be applied to a display device according to one aspect of the present invention will be described with reference to Figures 15 to 18.

[0345] The display device 500 shown in Figures 15A to 15C includes a light-emitting device 550R that emits red light, a light-emitting device 550G that emits green light, and a light-emitting device 550B that emits blue light.

[0346] The light-emitting device 550R shown in Figures 15A and 15B has a light-emitting unit 512R_1 between a pair of electrodes (electrode 501, electrode 502). Similarly, the light-emitting device 550G has a light-emitting unit 512G_1, and the light-emitting device 550B has a light-emitting unit 512B_1.

[0347] In other words, the light-emitting devices 550R, 550G, and 550B shown in Figures 15A and 15B are each single-structure light-emitting devices having one light-emitting unit.

[0348] The light-emitting device 550R shown in Figure 15C has a configuration in which two light-emitting units (light-emitting unit 512R_1, light-emitting unit 512R_2) are stacked between a pair of electrodes (electrode 501, electrode 502) via a charge generation layer 531. Similarly, the light-emitting device 550G has light-emitting unit 512G_1, light-emitting unit 512G_2, and the light-emitting device 550B has light-emitting unit 512B_1, light-emitting unit 512B_2.

[0349] In other words, the light-emitting devices 550R, 550G, and 550B shown in Figure 15C are each tandem-structured light-emitting devices having two light-emitting units.

[0350] In this specification, a configuration in which multiple light-emitting units are connected in series via a charge generation layer 531, such as the light-emitting devices 550R, 550G, and 550B shown in Figure 15C, is called a tandem structure. On the other hand, a configuration in which one light-emitting unit is located between a pair of electrodes, such as the light-emitting devices 550R, 550G, and 550B shown in Figures 15A and 15B, is called a single structure. In this specification, the term "tandem structure" is used, but it is not limited to this, and for example, a tandem structure may also be called a stacked structure. By using a tandem structure, it is possible to create a light-emitting device that can emit light with high brightness. Furthermore, compared to a single structure, a tandem structure can reduce the current required to obtain the same brightness, thus improving reliability.

[0351] Furthermore, a structure in which the light-emitting layer is made separately for each light-emitting device, as shown in the display device 500 in Figures 15A to 15C, is sometimes called an SBS (Side By Side) structure.

[0352] The display device 500 shown in Figure 15C has a tandem structure for its light-emitting devices and can be said to have an SBS structure. Therefore, it can combine the advantages of both a tandem structure and an SBS structure. The display device 500 shown in Figure 15C has a structure in which two light-emitting units are formed in series, so it may also be called a two-stage tandem structure. In the two-stage tandem structure of the light-emitting device 550R shown in Figure 15C, a second light-emitting unit having a red light-emitting layer is stacked on top of a first light-emitting unit having a red light-emitting layer. Similarly, in the two-stage tandem structure of the light-emitting device 550G shown in Figure 15C, a second light-emitting unit having a green light-emitting layer is stacked on top of a first light-emitting unit having a green light-emitting layer, and in the two-stage tandem structure of the light-emitting device 550B, a second light-emitting unit having a blue light-emitting layer is stacked on top of a first light-emitting unit having a blue light-emitting layer.

[0353] Electrode 501 functions as a pixel electrode and is provided for each light-emitting device. Electrode 502 functions as a common electrode and is provided in common to multiple light-emitting devices.

[0354] The light-emitting unit has at least one light-emitting layer. The number of light-emitting layers in the light-emitting unit is not limited to one, two, three, or four or more layers.

[0355] The light-emitting unit 512R_1 has layers 521, 522, light-emitting layer 523R, layer 524, etc. Figure 15A shows an example in which the light-emitting unit 512R_1 has layer 525, and Figure 15B shows an example in which the light-emitting unit 512R_1 does not have layer 525, and layer 525 is provided in common among the light-emitting devices. In this case, layer 525 can be called a common layer. By providing one or more common layers to multiple light-emitting devices in this way, the manufacturing process can be simplified, and thus manufacturing costs can be reduced.

[0356] The light-emitting unit 512R_2 includes layers 522, luminescent layer 523R, layer 524, etc. In Figure 15C, an example is shown in which layer 525 is provided as a common layer, but layer 525 may be provided for each light-emitting device. In other words, layer 525 may be included in the light-emitting unit 512R_2.

[0357] Layer 521 includes, for example, a layer containing a material with high hole injection capabilities (hole injection layer). Layer 522 includes, for example, a layer containing a material with high hole transport capabilities (hole transport layer). Layer 524 includes, for example, a layer containing a material with high electron transport capabilities (electron transport layer). Layer 525 includes, for example, a layer containing a material with high electron injection capabilities (electron injection layer).

[0358] Alternatively, the configuration may include layer 521 having an electron injection layer, layer 522 having an electron transport layer, layer 524 having a hole transport layer, and layer 525 having a hole injection layer.

[0359] Note that layer 522, light-emitting layer 523R, and layer 524 may have the same configuration (material, film thickness, etc.) in light-emitting unit 512R_1 and light-emitting unit 512R_2, or they may have different configurations.

[0360] In Figure 15A, etc., layers 521 and 522 are shown separately, but the design is not limited to this. For example, if layer 521 has the functions of both a hole injection layer and a hole transport layer, or if layer 521 has the functions of both an electron injection layer and an electron transport layer, layer 522 may be omitted.

[0361] Furthermore, the charge generation layer 531 has the function of injecting electrons into one of the light-emitting units 512R_1 and 512R_2 and holes into the other when a voltage is applied between the electrode 501 and the electrode 502. The charge generation layer 531 has at least a charge generation region.

[0362] The light-emitting layer 523R of the light-emitting device 550R contains a light-emitting material that emits red light, the light-emitting layer 523G of the light-emitting device 550G contains a light-emitting material that emits green light, and the light-emitting layer 523B of the light-emitting device 550B contains a light-emitting material that emits blue light. The light-emitting devices 550G and 550B have a configuration in which the light-emitting layer 523R of the light-emitting device 550R is replaced with the light-emitting layer 523G and the light-emitting layer 523B, respectively, and the other configurations are the same as those of the light-emitting device 550R.

[0363] Note that layers 521, 522, 524, and 525 may have the same configuration (material, film thickness, etc.) for each color of light-emitting device, or they may have different configurations.

[0364] In Figures 15A and 15B, the light-emitting units 512R_1, 512G_1, and 512B_1 can be formed as island-like layers. In other words, the layer 113 shown in Figures 15A and 15B corresponds to the first layer 113a, the second layer 113b, or the third layer 113c shown in Figure 1B, etc.

[0365] In Figure 15C, the light-emitting unit 512R_1, the charge generation layer 531, and the light-emitting unit 512R_2 can be formed as island-like layers. Similarly, the light-emitting unit 512G_1, the charge generation layer 531, and the light-emitting unit 512G_2 can be formed as island-like layers. The light-emitting unit 512B_1, the charge generation layer 531, and the light-emitting unit 512B_2 can also be formed as island-like layers. In other words, the layer 113 shown in Figure 15C corresponds to the first layer 113a, the second layer 113b, or the third layer 113c shown in Figure 1B, etc.

[0366] In Figures 15B and 15C, layer 525 corresponds to the fifth layer 114 shown in Figure 1B.

[0367] In addition, the light-emitting material of the light-emitting layer in the display device 500 is not particularly limited. For example, in the display device 500 shown in Figure 15C, the light-emitting layer 523R of the light-emitting unit 512R_1 has a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 has a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 has a fluorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 has a fluorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 has a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 has a fluorescent material.

[0368] Alternatively, in the display device 500 shown in Figure 15C, the light-emitting layer 523R of the light-emitting unit 512R_1 has a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 has a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 has a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 has a phosphorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 has a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 has a fluorescent material.

[0369] Furthermore, in one embodiment of the present invention, the display device may be configured such that all light-emitting layers are made of fluorescent material, or so that all light-emitting layers are made of phosphorescent material.

[0370] Alternatively, in the display device 500 shown in Figure 15C, the light-emitting layer 523R of the light-emitting unit 512R_1 may be made of a phosphorescent material and the light-emitting layer 523R of the light-emitting unit 512R_2 may be made of a fluorescent material, or the light-emitting layer 523R of the light-emitting unit 512R_1 may be made of a fluorescent material and the light-emitting layer 523R of the light-emitting unit 512R_2 may be made of a phosphorescent material, that is, the light-emitting materials of the first stage light-emitting layer and the second stage light-emitting layer may be made of different materials. Although the description here specifies light-emitting units 512R_1 and 512R_2, the same configuration can be applied to light-emitting units 512G_1 and 512G_2, and light-emitting units 512B_1 and 512B_2.

[0371] The display device 500 shown in Figures 16 to 18 includes a light-emitting device 550R that emits red light, a light-emitting device 550G that emits green light, a light-emitting device 550B that emits blue light, and a light-emitting device 550W that emits white light.

[0372] The display devices shown in Figures 16A and 16B are examples that include a white light-emitting device 550W in addition to the light-emitting devices 550R, 550G, and 550B shown in Figure 15B. The display device shown in Figure 17A is an example that includes a white light-emitting device 550W in addition to the light-emitting devices 550R, 550G, and 550B shown in Figure 15C.

[0373] The light-emitting device 550W shown in Figures 16A and 17A has a configuration in which two light-emitting units (light-emitting unit 512Q_1, light-emitting unit 512Q_2) are stacked between a pair of electrodes (electrode 501, electrode 502) via a charge generation layer 531.

[0374] The light-emitting device 550W shown in Figure 16B has a configuration in which three light-emitting units (light-emitting unit 512Q_1, light-emitting unit 512Q_2, and light-emitting unit 512Q_3) are stacked between a pair of electrodes (electrode 501, electrode 502) via a charge generation layer 531.

[0375] Light-emitting unit 512Q_1 has layers 521, 522, light-emitting layer 523Q_1, layer 524, etc. Light-emitting unit 512Q_2 has layers 522, light-emitting layer 523Q_2, layer 524, etc. Light-emitting unit 512Q_3 has layers 522, light-emitting layer 523Q_3, layer 524, etc.

[0376] In the light-emitting device 550W shown in Figures 16A and 17A, white light can be obtained from the light-emitting device 550W by selecting light-emitting layers 523Q_1 and 523Q_2 such that their light emission is complementary in color.

[0377] In the light-emitting device 550W shown in Figure 16B, white light emission can be obtained from the light-emitting device 550W by selecting light-emitting layers 523Q_1, 523Q_2, and 523Q_3 such that their light emission is in a complementary color relationship.

[0378] The light-emitting device 550W has a configuration in which the light-emitting layer 523R of the light-emitting device 550R is replaced with a light-emitting layer 523Q_1, etc., while the other configurations are the same as those of the light-emitting device 550R.

[0379] The display device 500 shown in Figure 17B is an example in which the light-emitting device 550R that emits red light, the light-emitting device 550G that emits green light, the light-emitting device 550B that emits blue light, and the light-emitting device 550W that emits white light all have a three-stage tandem structure in which three light-emitting units are stacked. In Figure 17B, the light-emitting device 550R has a light-emitting unit 512R_3 stacked on top of the light-emitting unit 512R_2 via a charge generation layer 531. The light-emitting unit 512R_3 has layers 522, light-emitting layer 523R, layer 524, etc. The same configuration can be applied to the light-emitting unit 512R_3 as to the light-emitting unit 512R_2. The same applies to the light-emitting unit 512G_3 of the light-emitting device 550G, the light-emitting unit 512B_3 of the light-emitting device 550B, and the light-emitting unit 512Q_3 of the light-emitting device 550W.

[0380] Figure 18A shows an example in which, in addition to the light-emitting devices 550R, 550G, and 550B shown in Figure 15A, a light-emitting device 550W that emits white light is also provided.

[0381] The light-emitting device 550W shown in Figure 18A has a configuration in which n light-emitting units (n is an integer of 2 or more) are stacked between a pair of electrodes (electrode 501, electrode 502) via a charge generation layer 531. The light-emitting device 550W has n light-emitting units, from light-emitting unit 512Q_1 to light-emitting unit 512Q_n, and can emit white light because the light from these light-emitting units is in a complementary color relationship.

[0382] In Figure 18B, the light-emitting device 550R that emits red light, the light-emitting device 550G that emits green light, the light-emitting device 550B that emits blue light, and the light-emitting device 550W that emits white light all have a configuration in which n light-emitting units (n is an integer of 2 or more) are stacked. The light-emitting device 550R has n light-emitting units, from light-emitting unit 512R_1 to light-emitting unit 512R_n, each having a light-emitting layer that emits red light. The light-emitting device 550G has n light-emitting units, from light-emitting unit 512G_1 to light-emitting unit 512G_n, each having a light-emitting layer that emits green light. The light-emitting device 550B has n light-emitting units, from light-emitting unit 512B_1 to light-emitting unit 512B_n, each having a light-emitting layer that emits blue light.

[0383] In this way, by increasing the number of stacked light-emitting units, the brightness obtained from the light-emitting device with the same amount of current can be increased in proportion to the number of stacks. Furthermore, by increasing the number of stacked light-emitting units, the current required to obtain the same brightness can be reduced, thus reducing the power consumption of the light-emitting device in proportion to the number of stacks.

[0384] This embodiment can be combined with other embodiments as appropriate.

[0385] (Embodiment 3) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 19 to 21.

[0386] The display device of this embodiment can be a high-resolution display device or a large-screen display device. Therefore, the display device of this embodiment can be used in electronic devices with relatively large screens, such as television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal information terminals, and audio playback devices.

[0387] [Display device 100A] Figure 19 shows a perspective view of the display device 100A, and Figure 20A shows a cross-sectional view of the display device 100A.

[0388] The display device 100A has a configuration in which substrate 152 and substrate 151 are bonded together. In Figure 19, substrate 152 is clearly indicated by a dashed line.

[0389] The display device 100A includes a display unit 162, a circuit 164, wiring 165, etc. Figure 19 shows an example in which IC 173 and FPC 172 are mounted on the display device 100A. Therefore, the configuration shown in Figure 19 can also be described as a display module having the display device 100A, an IC (integrated circuit), and an FPC.

[0390] For example, a scan line drive circuit can be used as circuit 164.

[0391] Wiring 165 has the function of supplying signals and power to the display unit 162 and the circuit 164. These signals and power are input to wiring 165 from an external source via FPC 172 or from IC 173.

[0392] Figure 19 shows an example in which IC 173 is provided on the substrate 151 using the COG (Chip On Glass) method or COF (Chip On Film) method, etc. IC 173 can be an IC having, for example, a scan line drive circuit or a signal line drive circuit. Note that the display device 100A and the display module may be configured without an IC. Alternatively, the IC may be mounted on an FPC using the COF method, etc.

[0393] Figure 20A shows an example of a cross-section obtained by cutting a portion of the display device 100A, including the FPC 172, a portion of the circuit 164, a portion of the display unit 162, and a portion of the area including the end.

[0394] The display device 100A shown in Figure 20A has a transistor 201, a transistor 205, a light-emitting device 130a that emits red light, a light-emitting device 130b that emits green light, and a light-emitting device 130c that emits blue light, etc., between substrates 151 and 152.

[0395] Here, if a pixel of a display device has three types of subpixels, each having a light-emitting device that emits light of different colors, examples of such three subpixels include subpixels of three colors: R, G, and B; and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). If there are four such subpixels, examples of such four subpixels include subpixels of four colors: R, G, B, and white (W); and subpixels of four colors: R, G, B, and Y.

[0396] The light-emitting devices 130a, 130b, and 130c each have a structure similar to the stacked structure shown in Figure 1B, except that they have an optical adjustment layer between the pixel electrode and the EL layer. Light-emitting device 130a has an optical adjustment layer 126a, light-emitting device 130b has an optical adjustment layer 126b, and light-emitting device 130c has an optical adjustment layer 126c. Details of the light-emitting devices can be found in Embodiment 1. The sides of the pixel electrodes 111a, 111b, 111c, the optical adjustment layers 126a, 126b, 126c, the first layer 113a, the second layer 113b, and the third layer 113c are covered by side walls 125a and 125b, respectively. A fifth layer 114 is provided on the first layer 113a, the second layer 113b, the third layer 113c, and the side walls 125a and 125b, and a common electrode 115 is provided on the fifth layer 114. In addition, a protective layer 131 is provided on each of the light-emitting devices 130a, 130b, and 130c. A protective layer 132 is provided on the protective layer 131.

[0397] Figure 20A shows an example where the thickness of optical adjustment layer 126a is greater than the thickness of optical adjustment layer 126b, and the thickness of optical adjustment layer 126b is greater than the thickness of optical adjustment layer 126c. Preferably, the thickness of optical adjustment layer 126a is set to enhance red light, the thickness of optical adjustment layer 126b is set to enhance green light, and the thickness of optical adjustment layer 126c is set to enhance blue light. This makes it possible to realize a microcavity structure and improve the color purity of the light emitted by each light-emitting device.

[0398] The optical adjustment layer is preferably formed using a conductive material that has transparency to visible light, among conductive materials that can be used as electrodes for light-emitting devices.

[0399] The protective layer 132 and the substrate 152 are bonded together via an adhesive layer 142. For sealing the light-emitting device, a solid sealing structure or a hollow sealing structure can be applied. In Figure 20A, the space between substrate 152 and substrate 151 is filled with the adhesive layer 142, demonstrating a solid sealing structure. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), demonstrating a hollow sealing structure. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting device. Furthermore, the space may be filled with a resin different from the frame-shaped adhesive layer 142.

[0400] The pixel electrodes 111a, 111b, and 111c are each connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214.

[0401] The pixel electrodes contain a material that reflects visible light, while the common electrode 115 (which can also be called the counter electrode) contains a material that transmits visible light.

[0402] The display device 100A is a top-emission type. The light emitted from the light-emitting device is emitted towards the substrate 152. It is preferable to use a material with high transparency to visible light for the substrate 152.

[0403] The laminated structure from the substrate 151 to the insulating layer 214 corresponds to the layer 101 containing the transistor in Embodiment 1.

[0404] Both transistors 201 and 205 are formed on the substrate 151. These transistors can be manufactured using the same materials and the same process.

[0405] On the substrate 151, insulating layers 211, 213, 215, and 214 are provided in this order. A portion of insulating layer 211 functions as a gate insulating layer for each transistor. A portion of insulating layer 213 functions as a gate insulating layer for each transistor. Insulating layer 215 is provided covering the transistors. Insulating layer 214 is provided covering the transistors and functions as a planarization layer. The number of gate insulating layers and insulating layers covering the transistors are not limited and may be a single layer or two or more layers, respectively.

[0406] It is preferable to use a material that does not easily allow impurities such as water and hydrogen to diffuse into at least one layer of the insulating layer covering the transistor. This allows the insulating layer to function as a barrier layer. With such a configuration, the diffusion of impurities from the outside into the transistor can be effectively suppressed, thereby improving the reliability of the display device.

[0407] It is preferable to use inorganic insulating films for insulating layer 211, insulating layer 213, and insulating layer 215. Examples of inorganic insulating films that can be used include silicon nitride film, silicon oxide nitride film, silicon oxide film, silicon nitride oxide film, aluminum oxide film, and aluminum nitride film. Alternatively, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, and neodymium oxide film may also be used. Furthermore, two or more of the above insulating films may be laminated together.

[0408] Here, organic insulating films often have lower barrier properties than inorganic insulating films. Therefore, it is preferable that the organic insulating film has an opening near the edge of the display device 100A. This prevents impurities from entering through the organic insulating film from the edge of the display device 100A. Alternatively, the organic insulating film may be formed so that its edge is inward from the edge of the display device 100A, so that the organic insulating film is not exposed at the edge of the display device 100A.

[0409] An organic insulating film is preferred for the insulating layer 214, which functions as a planarization layer. Examples of materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. Alternatively, the insulating layer 214 may have a laminated structure of an organic insulating film and an inorganic insulating film. The outermost layer of the insulating layer 214 preferably functions as an etching protective film. This suppresses the formation of recesses in the insulating layer 214 when processing the side walls 125a, 125b, etc. Alternatively, recesses may be provided in the insulating layer 214 when processing the side walls 125a, 125b, etc.

[0410] In the region 228 shown in Figure 20A, an opening is formed in the insulating layer 214. This prevents impurities from entering the display unit 162 from the outside through the insulating layer 214, even when an organic insulating film is used for the insulating layer 214. Therefore, the reliability of the display device 100A can be improved.

[0411] Transistors 201 and 205 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as source and drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0412] The transistor structure of the display device of this embodiment is not particularly limited. For example, planar transistors, staggered transistors, inverse staggered transistors, etc., can be used. Furthermore, either a top-gate or bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below the semiconductor layer in which the channel is formed.

[0413] Transistors 201 and 205 are configured in which a semiconductor layer on which a channel is formed is sandwiched between two gates. The transistors may be driven by connecting the two gates and supplying them with the same signal. Alternatively, the threshold voltage of the transistors may be controlled by applying a potential to control the threshold voltage to one of the two gates and a potential to drive the other gate.

[0414] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, single-crystal semiconductors, or semiconductors with crystalline properties other than single crystals (microcrystalline semiconductors, polycrystalline semiconductors, or semiconductors with crystalline regions in part) may be used. Using a single-crystal semiconductor or a semiconductor with crystalline properties is preferable because it can suppress the degradation of transistor characteristics.

[0415] The semiconductor layer of the transistor preferably has a metal oxide (also called an oxide semiconductor). In other words, the display device of this embodiment preferably uses a transistor (hereinafter referred to as an OS transistor) that uses a metal oxide in the channel formation region. Alternatively, the semiconductor layer of the transistor may have silicon. Examples of silicon include amorphous silicon and crystalline silicon (low-temperature polysilicon, single-crystal silicon, etc.).

[0416] The semiconductor layer preferably comprises, 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, M is preferably one or more selected from aluminum, gallium, yttrium, and tin.

[0417] In particular, it is preferable to use an oxide (also written as IGZO) containing indium (In), gallium (Ga), and zinc (Zn) as the semiconductor layer. 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.

[0418] When the semiconductor layer is an In-M-Zn oxide, it is preferable that the atomic ratio of In in the In-M-Zn oxide is equal to or greater than the atomic ratio of M. Examples of such In-M-Zn oxide atomic ratios of metal elements include compositions where In:M:Zn=1:1:1 or close to it, In:M:Zn=1:1:1.2 or close to it, In:M:Zn=2:1:3 or close to it, In:M:Zn=3:1:2 or close to it, In:M:Zn=4:2:3 or close to it, In:M:Zn=4:2:4.1 or close to it, In:M:Zn=5:1:3 or close to it, In:M:Zn=5:1:6 or close to it, In:M:Zn=5:1:7 or close to it, In:M:Zn=5:1:8 or close to it, In:M:Zn=6:1:6 or close to it, In:M:Zn=5:2:5 or close to it, and so on. Note that "close to it" compositions include a range of ±30% of the desired atomic ratio.

[0419] For example, when describing a composition with an atomic ratio of In:Ga:Zn = 4:2:3 or a similar ratio, it includes cases where, when In is set to 4, Ga is between 1 and 3, and Zn is between 2 and 4. Also, when describing a composition with an atomic ratio of In:Ga:Zn = 5:1:6 or a similar ratio, it includes cases where, when In is set to 5, Ga is greater than 0.1 and 2 or less, and Zn is between 5 and 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn = 1:1:1 or a similar ratio, it includes cases where, when In is set to 1, Ga is greater than 0.1 and 2 or less, and Zn is greater than 0.1 and 2 or less.

[0420] The transistors in circuit 164 and the transistors in display unit 162 may have the same structure or different structures. The structures of the multiple transistors in circuit 164 may all be the same or there may be two or more different structures. Similarly, the structures of the multiple transistors in display unit 162 may all be the same or there may be two or more different structures.

[0421] Figures 20B and 20C show other examples of transistor configurations.

[0422] Transistors 209 and 210 each have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer 231 having a channel forming region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel forming region 231i. The insulating layer 225 is located at least between the conductive layer 223 and the channel forming region 231i. Furthermore, an insulating layer 218 covering the transistor may be provided.

[0423] In the transistor 209 shown in Figure 20B, an example is shown where the insulating layer 225 covers the top and sides of the semiconductor layer 231. The conductive layers 222a and 222b are connected to the low-resistance region 231n through openings provided in the insulating layers 225 and 215, respectively. Of the conductive layers 222a and 222b, one functions as a source and the other as a drain.

[0424] On the other hand, in the transistor 210 shown in Figure 20C, the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231, but does not overlap with the low-resistance region 231n. For example, the structure shown in Figure 20C can be fabricated by processing the insulating layer 225 using the conductive layer 223 as a mask. In Figure 20C, an insulating layer 215 is provided covering the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and conductive layer 222b are connected to the low-resistance region 231n, respectively, through openings in the insulating layer 215.

[0425] A connection portion 204 is provided in the region of substrate 151 where substrate 152 does not overlap. At the connection portion 204, wiring 165 is electrically connected to FPC 172 via conductive layer 166 and connection layer 242. The conductive layer 166 is shown as an example of a laminated structure consisting of a conductive film obtained by processing the same conductive film as the pixel electrode and a conductive film obtained by processing the same conductive film as the optical adjustment layer 126c. The conductive layer 166 is exposed on the upper surface of the connection portion 204. This allows the connection portion 204 and FPC 172 to be electrically connected via the connection layer 242.

[0426] It is preferable to provide a light-shielding layer 117 on the surface of the substrate 152 that faces the substrate 151. Various optical components can also be placed on the outside of the substrate 152. Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (such as diffusion films), anti-reflective layers, and light-collecting films. Furthermore, an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, and an impact-absorbing layer may also be placed on the outside of the substrate 152.

[0427] By providing protective layers 131 and 132 that cover the light-emitting device, it is possible to suppress the ingress of impurities such as water into the light-emitting device and improve the reliability of the light-emitting device.

[0428] In the region 228 near the edge of the display device 100A, it is preferable that the insulating layer 215 and the protective layer 131 or protective layer 132 are in contact with each other through an opening in the insulating layer 214. In particular, it is preferable that the inorganic insulating films are in contact with each other. This makes it possible to suppress the entry of impurities into the display unit 162 from the outside through the organic insulating film. Therefore, the reliability of the display device 100A can be improved.

[0429] Substrates 151 and 152 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, etc., respectively. The substrate on the side that extracts light from the light-emitting device should be made of a material that transmits the light. Using flexible materials for substrates 151 and 152 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used as substrate 151 or substrate 152.

[0430] Substrates 151 and 152 can be made from polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. One or both of substrates 151 and 152 may be made of glass of a thickness sufficient to provide flexibility.

[0431] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy for the substrate of the display device. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence).

[0432] For substrates with high optical isotropy, the absolute value of the retardation (phase difference) is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0433] Examples of films with high optical isotropy include triacetylcellulose (TAC, also known as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0434] Furthermore, when using a film as the substrate, the film may absorb water, potentially causing wrinkles or other shape changes in the display panel. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferable to use a film with a water absorption rate of 0.1% or less, and even more preferable to use a film with a water absorption rate of 0.01% or less.

[0435] As the adhesive layer 142, various types of curing adhesives can be used, such as UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0436] As the connecting layer 242, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), etc., can be used.

[0437] Materials that can be used for conductive layers such as the gate, source, and drain of transistors, as well as various wirings and electrodes that constitute display devices, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys mainly composed of these metals. Films containing these materials can be used as single layers or in a multilayer structure.

[0438] Furthermore, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene can be used as the light-transmitting conductive material. Alternatively, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metallic materials, can be used. Alternatively, nitrides of such metallic materials (e.g., titanium nitride) may be used. When using metallic materials or alloy materials (or their nitrides), it is preferable to make them thin enough to be light-transmitting. In addition, a laminated film of the above materials can be used as a conductive layer. For example, using a laminated film of a silver-magnesium alloy and indium tin oxide is preferable because it can enhance conductivity. These can also be used as conductive layers for various wirings and electrodes that constitute a display device, and as conductive layers (conductive layers that function as pixel electrodes or common electrodes) in light-emitting devices.

[0439] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide, and aluminum oxide.

[0440] [Display device 100B] The display device 100B shown in Figure 21 differs from the display device 100A mainly in that it is a bottom-emission type. Parts that are the same as those of the display device 100A are omitted from the explanation.

[0441] The light emitted by the light-emitting device is projected onto the substrate 151. It is preferable to use a material with high transparency to visible light for the substrate 151. On the other hand, the light transmittance of the material used for the substrate 152 is not a requirement.

[0442] It is preferable to form a light-shielding layer 117 between the substrate 151 and the transistor 201, and between the substrate 151 and the transistor 205. Figure 21 shows an example in which a light-shielding layer 117 is provided on the substrate 151, an insulating layer 153 is provided on the light-shielding layer 117, and transistors 201, 205, etc. are provided on the insulating layer 153.

[0443] This embodiment can be combined with other embodiments as appropriate.

[0444] (Embodiment 4) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 22 to 25.

[0445] The display device of this embodiment can be a high-definition display device. Therefore, the display device of this embodiment can be used in the display section of wearable devices that can be worn on the head, such as information terminals (wearable devices) such as wristwatches and bracelets, as well as VR devices such as head-mounted displays and AR devices such as glasses.

[0446] [Display Module] Figure 22A shows a perspective view of the display module 280. The display module 280 includes a display device 100C and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100C, but may be the display device 100D or the display device 100E, which will be described later.

[0447] The display module 280 has substrates 291 and 292. The display module 280 has a display unit 281. The display unit 281 is an area in the display module 280 that displays an image, and is an area in which light from each pixel provided in the pixel unit 284, which will be described later, can be seen.

[0448] Figure 22B shows a schematic perspective view illustrating the configuration of the substrate 291. On the substrate 291, a circuit section 282, a pixel circuit section 283 on the circuit section 282, and a pixel section 284 on the pixel circuit section 283 are stacked. In addition, a terminal section 285 for connecting to the FPC 290 is provided in the portion of the substrate 291 that does not overlap with the pixel section 284. The terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286, which is composed of multiple wires.

[0449] The pixel section 284 has multiple pixels 284a arranged periodically. A magnified view of a single pixel 284a is shown on the right side of Figure 22B. Each pixel 284a has light-emitting devices 130a, 130b, and 130c, each with a different emission color. The multiple light-emitting devices can be arranged in a stripe pattern as shown in Figure 22B. Various arrangement methods for the light-emitting devices, such as a delta pattern or a pentile pattern, can also be applied.

[0450] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0451] A single pixel circuit 283a is a circuit that controls the light emission of three light-emitting devices in a single pixel 284a. A single pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting device. For example, a pixel circuit 283a can be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitive element for each light-emitting device. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain. This realizes an active-matrix type display device.

[0452] The circuit section 282 has circuits for driving each pixel circuit 283a of the pixel circuit section 283. For example, it is preferable to have one or both of a gate line drive circuit and a source line drive circuit. In addition, it may have at least one of the following: an arithmetic circuit, a memory circuit, and a power supply circuit.

[0453] The FPC290 functions as wiring for supplying video signals or power potential, etc., to the circuit section 282 from an external source. An IC may also be mounted on the FPC290.

[0454] The display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are superimposed on the lower side of the pixel section 284, thereby enabling an extremely high aperture ratio (effective display area ratio) of the display section 281. For example, the aperture ratio of the display section 281 can be 40% or more and less than 100%, preferably 50% or more and 95%, and more preferably 60% or more and 95%. Furthermore, it is possible to arrange the pixels 284a at an extremely high density, enabling an extremely high resolution of the display section 281. For example, it is preferable that the pixels 284a in the display section 281 are arranged with a resolution of 20000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and with a resolution of 20000 ppi or less, or 30000 ppi or less.

[0455] Because such a display module 280 is extremely high-resolution, it can be suitably used in VR devices such as head-mounted displays, or in glasses-type AR devices. For example, even in a configuration where the display part of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display part 281, so even when the display part is magnified with lenses, pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 280 is not limited to this, and can be suitably used in electronic devices with relatively small display parts. For example, it can be suitably used in the display part of wearable electronic devices such as wristwatches.

[0456] [Display device 100C] The display device 100C shown in Figure 23 comprises a substrate 301, light-emitting devices 130a, 130b, and 130c, a capacitor 240, and a transistor 310.

[0457] Substrate 301 corresponds to substrate 291 in Figures 22A and 22B. The laminated structure from substrate 301 to insulating layer 255b corresponds to layer 101 containing the transistor in Embodiment 1.

[0458] The transistor 310 is a transistor having a channel-forming region in the substrate 301. The substrate 301 can be a semiconductor substrate such as a single-crystal silicon substrate. The transistor 310 comprises a portion of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region of the substrate 301 doped with impurities and functions as either a source or a drain. The insulating layer 314 is provided covering the side surface of the conductive layer 311.

[0459] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0460] Furthermore, an insulating layer 261 is provided covering the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0461] Capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located between them. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as the dielectric of the capacitor 240.

[0462] The conductive layer 241 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is electrically connected to either the source or drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided covering the conductive layer 241. The conductive layer 245 is provided in the region that overlaps with the conductive layer 241 via the insulating layer 243.

[0463] An insulating layer 255a is provided covering the capacitance 240, an insulating layer 255b is provided on the insulating layer 255a, and light-emitting devices 130a, 130b, 130c, etc. are provided on the insulating layer 255b. In this embodiment, an example is shown in which the light-emitting devices 130a, 130b, 130c have a structure similar to the stacked structure shown in Figure 1B. The sides of the pixel electrodes 111a, 111b, 111c, the first layer 113a, the second layer 113b, and the third layer 113c are covered by side walls 125a, 125b, respectively. A fifth layer 114 is provided on the first layer 113a, the second layer 113b, the third layer 113c, and the side walls 125a, 125b, and a common electrode 115 is provided on the fifth layer 114. Furthermore, a protective layer 131 is provided on the light-emitting devices 130a, 130b, and 130c. A protective layer 132 is provided on the protective layer 131, and the substrate 120 is bonded to the protective layer 132 by a resin layer 122. Details of the components from the light-emitting devices to the substrate 120 can be found in Embodiment 1. The substrate 120 corresponds to the substrate 292 in Figure 22A.

[0464] Various inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride-oxide insulating films can be suitably used as insulating layers 255a and 255b, respectively. For insulating layer 255a, it is preferable to use an oxide insulating film or oxidative nitride insulating film such as a silicon oxide film, silicon oxidative nitride film, or aluminum oxide film. For insulating layer 255b, it is preferable to use a nitride insulating film or oxidative nitride insulating film such as a silicon nitride film or silicon nitride-oxide film. More specifically, it is preferable to use a silicon oxide film as insulating layer 255a and a silicon nitride film as insulating layer 255b. It is preferable that insulating layer 255b functions as an etching protective film. Alternatively, a nitride insulating film or nitride-oxide insulating film may be used as insulating layer 255a, and an oxide insulating film or oxidative nitride insulating film may be used as insulating layer 255b. In this embodiment, an example is shown in which a recess is provided in the insulating layer 255b, but the insulating layer 255b does not necessarily have to have a recess.

[0465] The pixel electrodes of the light-emitting device are electrically connected to either the source or drain of the transistor 310 by plugs 256 embedded in insulating layers 255a and 255b, a conductive layer 241 embedded in insulating layer 254, and a plug 271 embedded in insulating layer 261. The height of the upper surface of insulating layer 255b and the height of the upper surface of plug 256 are equal or approximately equal. Various conductive materials can be used for the plugs.

[0466] [Display device 100D] The display device 100D shown in Figure 24 differs from the display device 100C mainly in its transistor configuration. Note that explanations of parts similar to those of the display device 100C may be omitted.

[0467] Transistor 320 is an OS transistor in which a metal oxide (also called an oxide semiconductor) is applied to the semiconductor layer where the channel is formed.

[0468] The transistor 320 has a semiconductor layer 321, an insulating layer 323, a conductive layer 324, a pair of conductive layers 325, an insulating layer 326, and a conductive layer 327.

[0469] Substrate 331 corresponds to substrate 291 in Figures 22A and 22B. The laminated structure from substrate 331 to insulating layer 255b corresponds to layer 101 containing the transistor in Embodiment 1. An insulating substrate or a semiconductor substrate can be used as substrate 331.

[0470] An insulating layer 332 is provided on the substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320, and prevents oxygen from detaching from the semiconductor layer 321 to the insulating layer 332. As the insulating layer 332, for example, a film that is less susceptible to hydrogen or oxygen diffusion than a silicon oxide film can be used, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0471] A conductive layer 327 is provided on an insulating layer 332, and an insulating layer 326 is provided covering the conductive layer 327. The conductive layer 327 functions as the first gate electrode of the transistor 320, and a portion of the insulating layer 326 functions as the first gate insulating layer. It is preferable to use an oxide insulating film, such as a silicon oxide film, for at least the portion of the insulating layer 326 that is in contact with the semiconductor layer 321. It is preferable that the upper surface of the insulating layer 326 is flattened.

[0472] The semiconductor layer 321 is provided on the insulating layer 326. Preferably, the semiconductor layer 321 has a metal oxide (also called an oxide semiconductor) film having semiconductor properties. Details of materials suitable for use in the semiconductor layer 321 will be described later.

[0473] A pair of conductive layers 325 are provided in contact with the semiconductor layer 321 and function as source and drain electrodes.

[0474] Furthermore, an insulating layer 328 is provided covering the top and side surfaces of the pair of conductive layers 325, as well as the side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided on the insulating layer 328. The insulating layer 328 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing into the semiconductor layer 321 from the insulating layer 264, etc., and to prevent oxygen from detaching from the semiconductor layer 321. As the insulating layer 328, an insulating film similar to that of the insulating layer 332 can be used.

[0475] An opening is provided in the insulating layer 328 and the insulating layer 264 that reaches the semiconductor layer 321. Inside this opening, the insulating layer 323 and the conductive layer 324 are embedded, in contact with the sides of the insulating layer 264, the insulating layer 328, and the conductive layer 325, as well as the upper surface of the semiconductor layer 321. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0476] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are flattened so that their heights are the same or approximately the same, and the insulating layer 329 and insulating layer 265 are provided covering them.

[0477] Insulating layers 264 and 265 function as interlayer insulating layers. Insulating layer 329 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing into the transistor 320 from insulating layer 265, etc. As insulating layer 329, an insulating film similar to that used for insulating layers 328 and 332 can be used.

[0478] A plug 274, which is electrically connected to one of the pair of conductive layers 325, is provided so as to be embedded in the insulating layers 265, 329, and 264. Here, it is preferable that the plug 274 has a conductive layer 274a that covers the sides of the openings of the insulating layers 265, 329, 264, and 328, and a part of the upper surface of the conductive layer 325, and a conductive layer 274b that is in contact with the upper surface of the conductive layer 274a. In this case, it is preferable to use a conductive material that does not easily allow hydrogen and oxygen to diffuse as the conductive layer 274a.

[0479] The configuration from the insulating layer 254 to the substrate 120 in the display device 100D is the same as that of the display device 100C.

[0480] [Display device 100E] The display device 100E shown in Figure 25 has a configuration in which a transistor 310 with a channel formed on a substrate 301 and a transistor 320 containing a metal oxide in the semiconductor layer where the channel is formed are stacked. Note that parts that are the same as those of display devices 100C and 100D may be omitted from the explanation.

[0481] An insulating layer 261 is provided covering the transistor 310, and a conductive layer 251 is provided on the insulating layer 261. An insulating layer 262 is provided covering the conductive layer 251, and a conductive layer 252 is provided on the insulating layer 262. The conductive layers 251 and 252 each function as wiring. An insulating layer 263 and an insulating layer 332 are provided covering the conductive layer 252, and a transistor 320 is provided on the insulating layer 332. An insulating layer 265 is provided covering the transistor 320, and a capacitor 240 is provided on the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0482] Transistor 320 can be used as a transistor constituting a pixel circuit. Transistor 310 can also be used as a transistor constituting a pixel circuit, or as a transistor constituting a drive circuit (gate line drive circuit, source line drive circuit) for driving the pixel circuit. Furthermore, transistors 310 and 320 can be used as transistors constituting various circuits such as arithmetic circuits or memory circuits.

[0483] This configuration allows for the formation of not only pixel circuits but also drive circuits directly beneath the light-emitting device, making it possible to miniaturize the display device compared to cases where the drive circuits are located around the display area.

[0484] This embodiment can be combined with other embodiments as appropriate.

[0485] (Embodiment 5) 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 containing silicon is used as the semiconductor in which the channel is formed.

[0486] 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.

[0487] 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.

[0488] 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.

[0489] 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 as the semiconductor in which the channel is formed. OS transistors have extremely high field-effect mobility compared to amorphous silicon. In addition, OS transistors have a remarkably small source-drain leakage current (hereinafter also called an off-current) in the off state, and can retain the charge stored in a capacitor 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.

[0490] 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 to apply LTPS transistors to transistors that control current.

[0491] 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.

[0492] 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 makes it possible to maintain the gradation of pixels even when the frame frequency is significantly reduced (e.g., 1 fps or less), and thus power consumption can be reduced by stopping the driver when displaying still images.

[0493] Below, we will explain more specific configuration examples with reference to the drawings.

[0494] [Example of display device configuration 2] Figure 26A shows a block diagram of the display device 10. The display device 10 includes a display unit 11, a drive circuit unit 12, a drive circuit unit 13, and the like.

[0495] The display unit 11 has a plurality of pixels 30 arranged in a matrix. Each pixel 30 has sub-pixels 21R, 21G, and 21B. Each of the sub-pixels 21R, 21G, and 21B has a light-emitting device that functions as a display device.

[0496] Pixel 30 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 12. Wiring GL is electrically connected to the drive circuit unit 13. The drive circuit unit 12 functions as a source line drive circuit (also called a source driver), and the drive circuit unit 13 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.

[0497] Sub-pixel 21R has a light-emitting device that emits red light. Sub-pixel 21G has a light-emitting device that emits green light. Sub-pixel 21B has a light-emitting device that emits blue light. This allows the display device 10 to display in full color. Note that pixel 30 may have sub-pixels that emit light-emitting devices of other colors. For example, in addition to the three sub-pixels described above, pixel 30 may have a sub-pixel that emits white light, or a sub-pixel that emits yellow light, and so on.

[0498] Wiring GL is electrically connected to sub-pixels 21R, 21G, and 21B, which are arranged in the row direction (the direction in which wiring GL extends). Wirings SLR, SLG, and SLB are electrically connected to sub-pixels 21R, 21G, or 21B (not shown), which are arranged in the column direction (the direction in which wiring SLR, etc. extends).

[0499] [Example of pixel circuit configuration] Figure 26B shows an example of a circuit diagram of a pixel 21 that can be applied to the sub-pixels 21R, 21G, and 21B described above. Pixel 21 has transistors M1, M2, M3, capacitor C1, and light-emitting device EL. Wiring GL and wiring SL are electrically connected to pixel 21. Wiring SL corresponds to one of the wirings SLR, SLG, and SLB shown in Figure 26A.

[0500] 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 capacitor 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 EL, the other electrode of capacitor C1, and one of its source and drain. Transistor M3 has its gate electrically connected to wiring GL, and the other of its source and drain electrically connected to wiring RL. Light-emitting device EL has its other electrode electrically connected to wiring CL.

[0501] A data potential is supplied to wiring SL. A selection signal is supplied to wiring GL. This selection signal includes a potential that makes the transistor conduct and a potential that makes it non-conductive.

[0502] 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 21, the anode potential is set to a potential higher than the cathode potential. The reset potential applied to wiring RL can be set to a potential such that the potential difference between the reset potential and the cathode potential is smaller than the threshold voltage of the light-emitting device EL. 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.

[0503] Transistors M1 and M3 function as switches. Transistor M2 functions as a transistor for controlling the current flowing to the light-emitting device EL. For example, it can be said that transistor M1 functions as a selector transistor and transistor M2 functions as a drive transistor.

[0504] 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.

[0505] 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 12 and the drive circuit unit 13 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 11, and LTPS transistors may be applied to the transistors provided in the drive circuit unit 12 and the drive circuit unit 13.

[0506] Transistors using oxide semiconductors, which have a wider bandgap and lower carrier concentration than silicon, can achieve extremely small off-currents. Therefore, this small off-current allows the charge stored in a capacitor 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 capacitor C1. By using transistors with oxide semiconductors as transistors M1 and M3, it is possible to prevent the charge held in capacitor C1 from leaking through transistor M1 or M3. Furthermore, because the charge held in capacitor C1 can be retained for extended periods, it becomes possible to display still images for extended periods without rewriting the data in pixel 21.

[0507] Note that in Figure 26B, the transistor is shown as an n-channel type transistor, but a p-channel type transistor can also be used.

[0508] Furthermore, it is preferable that each transistor in the pixel 21 be formed in a row on the same substrate.

[0509] As the transistor in pixel 21, a transistor having a pair of gates that overlap across a semiconductor layer can be applied.

[0510] 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.

[0511] The pixel 21 shown in Figure 26C 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 21.

[0512] The pixel 21 shown in Figure 26D 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 EL and improving the display quality.

[0513] [Example of transistor configuration] The following describes examples of transistor cross-sectional configurations that can be applied to the above-mentioned display device.

[0514] [Configuration Example 1] Figure 27A is a cross-sectional view including transistor 410.

[0515] Transistor 410 is provided on substrate 401 and is a transistor in which polycrystalline silicon is applied to the semiconductor layer. For example, transistor 410 corresponds to transistor M2 of pixel 21. That is, Figure 27A is an example in which one of the source and drain of transistor 410 is electrically connected to the conductive layer 431 of the light-emitting device.

[0516] The transistor 410 has a semiconductor layer 411, an insulating layer 412, a conductive layer 413, etc. The semiconductor layer 411 has a channel-forming region 411i and a low-resistance region 411n. The semiconductor layer 411 is made of silicon. Preferably, the semiconductor layer 411 is made of polycrystalline silicon. A portion of the insulating layer 412 functions as a gate insulating layer. A portion of the conductive layer 413 functions as a gate electrode.

[0517] Furthermore, the semiconductor layer 411 may also be configured to include a metal oxide (also called an oxide semiconductor) that exhibits semiconductor properties. In this case, the transistor 410 can be called an OS transistor.

[0518] The low-resistance region 411n is a region containing impurity elements. For example, if transistor 410 is an n-channel type transistor, phosphorus, arsenic, etc., can be added to the low-resistance region 411n. On the other hand, if it is a p-channel type transistor, boron, aluminum, etc., can be added to the low-resistance region 411n. Furthermore, in order to control the threshold voltage of transistor 410, the aforementioned impurities may also be added to the channel formation region 411i.

[0519] An insulating layer 421 is provided on the substrate 401. The semiconductor layer 411 is provided on the insulating layer 421. The insulating layer 412 is provided covering the semiconductor layer 411 and the insulating layer 421. The conductive layer 413 is provided on the insulating layer 412 in a position overlapping with the semiconductor layer 411.

[0520] Furthermore, an insulating layer 422 is provided covering the conductive layer 413 and the insulating layer 412. Conductive layers 414a and 414b are provided on the insulating layer 422. Conductive layers 414a and 414b are electrically connected to the low-resistance region 411n at openings provided in the insulating layers 422 and 412. A portion of the conductive layer 414a functions as one of the source electrode and drain electrode, and a portion of the conductive layer 414b functions as the other of the source electrode and drain electrode. In addition, an insulating layer 423 is provided covering the conductive layer 414a, conductive layer 414b, and insulating layer 422.

[0521] A conductive layer 431, which functions 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 at an opening provided in the insulating layer 423. Although not shown here, an EL layer and a common electrode can be laminated on the conductive layer 431.

[0522] [Configuration Example 2] Figure 27B shows a transistor 410a having a pair of gate electrodes. The transistor 410a shown in Figure 27B differs from that in Figure 27A mainly in that it has a conductive layer 415 and an insulating layer 416.

[0523] The conductive layer 415 is provided on the insulating layer 421. Furthermore, an insulating layer 416 is provided covering the conductive layer 415 and the insulating layer 421. The semiconductor layer 411 is provided such that at least the channel-forming region 411i overlaps with the conductive layer 415 via the insulating layer 416.

[0524] In the transistor 410a shown in Figure 27B, a portion of the conductive layer 413 functions as a first gate electrode, and a portion of the conductive layer 415 functions as a second gate electrode. At the same time, a portion of the insulating layer 412 functions as a first gate insulating layer, and a portion of the insulating layer 416 functions as a second gate insulating layer.

[0525] 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.

[0526] When LTPS transistors are applied to all transistors constituting pixel 21, transistor 410 as exemplified in Figure 27A, or transistor 410a as exemplified in Figure 27B, can be applied. In this case, transistor 410a may be used for all transistors constituting pixel 21, transistor 410 may be applied to all transistors, or a combination of transistor 410a and transistor 410 may be used.

[0527] [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.

[0528] Figure 27C shows a schematic cross-sectional view including transistors 410a and 450.

[0529] 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.

[0530] Transistor 450 is a transistor in which a metal oxide is applied to the semiconductor layer. The configuration shown in Figure 27C is an example in which, for example, transistor 450 corresponds to transistor M1 of pixel 21 and transistor 410a corresponds to transistor M2. That is, Figure 27C is an example in which one of the source and drain of transistor 410a is electrically connected to the conductive layer 431.

[0531] Figure 27C also shows an example where transistor 450 has a pair of gates.

[0532] The transistor 450 has a conductive layer 455, an insulating layer 422, a semiconductor layer 451, an insulating layer 452, a conductive layer 453, etc. 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.

[0533] 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.

[0534] 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.

[0535] 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 27C 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.

[0536] 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 27C 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.

[0537] In Figure 27C, 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 the transistor 450a in Figure 27D, the insulating layer 452 may be processed so that its upper surface shape matches or roughly matches that of the conductive layer 453.

[0538] 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."

[0539] In this example, transistor 410a corresponds to transistor M2 and is electrically connected to the pixel electrode, but this is not the only example. For example, transistor 450 or transistor 450a may correspond to transistor M2. In this case, transistor 410a corresponds to transistor M1, transistor M3, or another transistor.

[0540] This embodiment can be combined with other embodiments as appropriate.

[0541] (Embodiment 6) This embodiment describes metal oxides (also called oxide semiconductors) that can be used in the OS transistor described in the above embodiment.

[0542] The metal oxide preferably contains at least indium or zinc. It is particularly preferable that it contains indium and zinc. In addition, it is preferable that it contains aluminum, gallium, yttrium, tin, etc. It may also contain one or more selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, etc.

[0543] Furthermore, metal oxides can be formed by methods such as sputtering, chemical vapor deposition (CVD) methods including metal-organic chemical vapor deposition (MOCVD), or atomic layer deposition (ALD).

[0544] <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.

[0545] 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 known as the thin-film method or the Seemann-Bohlin method.

[0546] For example, in a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, in an IGZO film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical shape of the XRD spectrum peak 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.

[0547] 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. However, in the diffraction pattern of an IGZO film deposited at room temperature, a spot-like pattern is observed instead of a halo. Therefore, it is presumed that an IGZO film deposited at room temperature is in an intermediate state, neither crystalline nor amorphous, and cannot be concluded to be in an amorphous state.

[0548] <<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. Non-single-crystal oxide semiconductors also include polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0549] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0550] [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.

[0551] Each of the multiple crystalline regions described above 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 a single minute crystal, the maximum diameter of that crystalline region is 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.

[0552] Furthermore, in In-M-Zn oxides (where element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), 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 element M, zinc (Zn), and oxygen (hereinafter referred to as the (M,Zn) layer). Note that indium and element M are mutually substitutable. Therefore, the (M,Zn) layer may contain indium. Also, the In layer may contain element M. Also, the In layer may contain Zn. This layered structure can be observed, for example, as a lattice image in high-resolution TEM (Transmission Electron Microscope) images.

[0553] When structural analysis of a CAAC-OS film is performed using an XRD instrument, for example, 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 c-axis orientation peak (value of 2θ) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0554] 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.

[0555] 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 lattice arrangements such as pentagons or heptagons. 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 fact that the arrangement of oxygen atoms is not dense in the ab-plane direction, and the bond distance between atoms changes due to the substitution of metal atoms.

[0556] 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 transistor 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 than In oxide.

[0557] 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 (such as 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.

[0558] [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 larger), 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.

[0559] [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.

[0560] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0561] [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 these 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.

[0562] 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.

[0563] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting CAC-OS in In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in CAC-OS in In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of CAC-OS. The second region is the region where [Ga] is greater than the [Ga] in the composition of CAC-OS. 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.

[0564] Specifically, the first region described above is a region whose main components are indium oxide, indium zinc oxide, etc. The second region described above is a region whose main components are gallium oxide, gallium zinc oxide, etc. In other words, the first region can be rephrased as a region whose main component is In. Similarly, the second region can be rephrased as a region whose main component is Ga.

[0565] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

[0566] 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.

[0567] CAC-OS can be formed, for example, by sputtering under conditions where the substrate is not 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 film-forming gas. Furthermore, it is preferable that the ratio of the oxygen gas flow rate to the total flow rate of the film-forming gas during film formation be as low as possible. For example, it is preferable that the ratio of the oxygen gas flow rate to the total flow rate of the film-forming gas during film formation be 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0568] 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.

[0569] 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.

[0570] On the other hand, the second region is a region with 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.

[0571] 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.

[0572] Furthermore, transistors using CAC-OS offer high reliability. Therefore, CAC-OS is ideal for various semiconductor devices, including display devices.

[0573] 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.

[0574] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0575] 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.

[0576] 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 -3More 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.

[0577] Furthermore, oxide semiconductor films that are highly intrinsic or substantially highly intrinsic may have a low trap level density due to their low defect level density.

[0578] 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.

[0579] Therefore, reducing the impurity concentration in the oxide semiconductor is effective in stabilizing the electrical characteristics of the 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.

[0580] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0581] 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:

[0582] 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:

[0583] 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 3 More preferably 1 × 10 18 atoms / cm 3 More preferably 5 × 10 17 atoms / cm 3 Do the following:

[0584] 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, which act 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, in oxide semiconductors, the hydrogen concentration 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.

[0585] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be provided.

[0586] This embodiment can be combined with other embodiments as appropriate.

[0587] (Embodiment 7) In this embodiment, an electronic device according to one aspect of the present invention will be described with reference to Figures 28 to 32.

[0588] 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.

[0589] Examples of electronic devices include television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as other electronic devices with relatively large screens, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, and audio playback devices.

[0590] 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), as well as wearable devices that can be worn on the head, such as VR devices such as head-mounted displays, AR devices such as glasses, and MR devices.

[0591] 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 that has either high resolution or high detail, or both, it becomes possible to further enhance the sense of presence and depth in personal electronic devices such as portable or home-use devices. Furthermore, there are no particular limitations on the screen ratio (aspect ratio) of the display device according to one embodiment of the present invention. For example, the display device can support various screen ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0592] 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).

[0593] The electronic device of this embodiment can have a variety of functions. For example, it can have a function to display various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function to display a calendar, date or time, a function to execute various software (programs), a wireless communication function, a function to read programs or data recorded on a recording medium, and so on.

[0594] Figures 28A, 28B, 29A, and 29B illustrate an example of a wearable device that can be worn on the head. These wearable devices have either or both the function of displaying AR content and / or the function of displaying VR content. In addition to AR and VR, these wearable devices may also have the function of displaying SR or MR content. By having electronic devices that can display AR, VR, SR, MR, etc., it is possible to enhance the user's sense of immersion.

[0595] The electronic device 700A shown in Figure 28A and the electronic device 700B shown in Figure 28B each include a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0596] A display device according to one aspect of the present invention can be applied to the display panel 751. Therefore, an electronic device capable of displaying extremely high resolution can be created.

[0597] Electronic devices 700A and 700B can project an image displayed on the display panel 751 onto the display area 756 of the optical element 753. Because the optical element 753 is translucent, the user can see the image displayed on the display area superimposed on the transmitted image visible through the optical element 753. Therefore, electronic devices 700A and 700B are electronic devices capable of AR display.

[0598] Electronic devices 700A and 700B may be equipped with cameras capable of capturing images of the area in front of them as imaging units. Furthermore, electronic devices 700A and 700B may each be equipped with acceleration sensors such as gyro sensors to detect the orientation of the user's head and display an image corresponding to that orientation in the display area 756.

[0599] The communications unit has a wireless communication device, which can supply video signals and the like. Alternatively, instead of the wireless communication device, or in addition to the wireless communication device, it may be equipped with a connector to which a cable supplying video signals and power potential can be connected.

[0600] Furthermore, electronic devices 700A and 700B are equipped with batteries that can be charged wirelessly, wired, or both.

[0601] The housing 721 may be equipped with a touch sensor module. The touch sensor module has the function of detecting when the outer surface of the housing 721 is touched. The touch sensor module can detect the user's tap or slide operations and perform various processes. For example, a tap operation can be used to pause or resume the video, and a slide operation can be used to fast forward or rewind. Furthermore, by providing a touch sensor module in each of the two housings 721, the range of operations can be expanded.

[0602] Various types of touch sensors can be applied to the touch sensor module. For example, various methods such as capacitive, resistive, infrared, electromagnetic induction, surface acoustic wave, and optical sensors can be used. In particular, it is preferable to apply a capacitive or optical sensor to the touch sensor module.

[0603] When using an optical touch sensor, a photoelectric conversion device (also called a photoelectric element) can be used as the light-receiving device (also called a photoelectric element). The active layer of the photoelectric conversion device can be made of either an inorganic semiconductor or an organic semiconductor, or both.

[0604] The electronic device 800A shown in Figure 29A and the electronic device 800B shown in Figure 29B each include a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0605] A display device according to one embodiment of the present invention can be applied to the display unit 820. Therefore, an electronic device capable of displaying extremely high resolution can be created. This allows the user to experience a high level of immersion.

[0606] The display unit 820 is located inside the housing 821, in a position where it can be seen through the lens 832. Furthermore, by displaying different images on a pair of display units 820, a three-dimensional display using parallax can also be performed.

[0607] Electronic devices 800A and 800B can be described as electronic devices for VR. A user wearing either electronic device 800A or electronic device 800B can view the image displayed on the display unit 820 through the lens 832.

[0608] It is preferable that electronic devices 800A and 800B each have a mechanism that allows adjustment of the left and right positions of the lens 832 and the display unit 820 so that they are in the optimal position according to the user's eye position. It is also preferable that they have a mechanism that adjusts the focus by changing the distance between the lens 832 and the display unit 820.

[0609] The attachment portion 823 allows the user to attach the electronic device 800A or 800B to their head. While Figure 29A and other figures illustrate the attachment portion as resembling the temples (or joints) of eyeglasses, it is not limited to this shape. The attachment portion 823 only needs to be wearable by the user; for example, it may be helmet-shaped or band-shaped.

[0610] The imaging unit 825 has the function of acquiring external information. The data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used in the imaging unit 825. In addition, multiple cameras may be provided to accommodate multiple angles of view, such as telephoto and wide-angle.

[0611] Although an example with an imaging unit 825 is shown here, any distance measuring sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object can be provided. In other words, the imaging unit 825 is one form of a detection unit. As the detection unit, for example, an image sensor or a distance image sensor such as LiDAR (Light Detection and Ranging) can be used. By using the image obtained by the camera and the image obtained by the distance image sensor, more information can be acquired, enabling more accurate gesture control.

[0612] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone. For example, a configuration having such a vibration mechanism can be applied to one or more of the display unit 820, housing 821, and mounting unit 823. This allows users to enjoy video and audio simply by wearing the electronic device 800A, without needing separate audio equipment such as headphones, earphones, or speakers.

[0613] Electronic devices 800A and 800B may each have input terminals. Cables can be connected to the input terminals to supply video signals from video output devices, etc., and power for charging batteries provided within the electronic devices.

[0614] An electronic device according to one aspect of the present invention may have a function for wireless communication with an earphone 750. The earphone 750 has a communication unit (not shown) and has a wireless communication function. The earphone 750 can receive information (e.g., voice data) from the electronic device through its wireless communication function. For example, the electronic device 700A shown in Figure 28A has a function for transmitting information to the earphone 750 through its wireless communication function. Also, for example, the electronic device 800A shown in Figure 29A has a function for transmitting information to the earphone 750 through its wireless communication function.

[0615] Furthermore, the electronic device may have an earphone section. The electronic device 700B shown in Figure 28B has an earphone section 727. For example, the earphone section 727 and the control section can be connected to each other by a wire. Part of the wiring connecting the earphone section 727 and the control section may be located inside the housing 721 or the mounting section 723.

[0616] Similarly, the electronic device 800B shown in Figure 29B has an earphone unit 827. For example, the earphone unit 827 and the control unit 824 can be connected to each other by a wire. Part of the wiring connecting the earphone unit 827 and the control unit 824 may be located inside the housing 821 or the mounting unit 823. Also, the earphone unit 827 and the mounting unit 823 may have magnets. This allows the earphone unit 827 to be fixed to the mounting unit 823 by magnetic force, which is preferable as it facilitates storage.

[0617] Furthermore, the electronic device may have an audio output terminal to which earphones or headphones can be connected. The electronic device may also have an audio input terminal and / or an audio input mechanism. For example, a sound-collecting device such as a microphone can be used as the audio input mechanism. By having an audio input mechanism, the electronic device may be given the function of a so-called headset.

[0618] Thus, as one embodiment of the present invention, both eyeglass-type (electronic devices 700A and 700B, etc.) and goggle-type (electronic devices 800A and 800B, etc.) are preferred as electronic devices.

[0619] Furthermore, an electronic device according to one aspect of the present invention can transmit information to earphones via wired or wireless means.

[0620] The electronic device 6500 shown in Figure 30A is a portable information terminal that can be used as a smartphone.

[0621] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508, etc. The display unit 6502 has a touch panel function.

[0622] A display device according to one aspect of the present invention can be applied to the display unit 6502.

[0623] Figure 30B is a schematic cross-sectional view of the housing 6501, including the end on the microphone 6506 side.

[0624] A light-transmitting protective member 6510 is provided on the display side of the housing 6501, and the display panel 6511, optical member 6512, touch sensor panel 6513, printed circuit board 6517, battery 6518, etc. are arranged in the space enclosed by the housing 6501 and the protective member 6510.

[0625] The protective member 6510 is fixed to the display panel 6511, the optical member 6512, and the touch sensor panel 6513 by an adhesive layer (not shown).

[0626] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and the FPC 6515 is connected to this folded portion. IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals provided on the printed circuit board 6517.

[0627] A flexible display according to one embodiment of the present invention can be applied to the display panel 6511. This makes it possible to realize an extremely lightweight electronic device. Furthermore, because the display panel 6511 is extremely thin, it is possible to incorporate a large-capacity battery 6518 while keeping the thickness of the electronic device low. In addition, by folding back a part of the display panel 6511 and placing the connection part with the FPC 6515 on the back of the pixel area, it is possible to realize an electronic device with a narrow bezel.

[0628] Figure 31A 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.

[0629] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0630] The television device 7100 shown in Figure 31A 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 or the like. 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.

[0631] 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 (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0632] Figure 31B shows an example of a notebook personal computer. The notebook personal computer 7200 has a casing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, etc. A display unit 7000 is incorporated into the casing 7211.

[0633] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0634] Figures 31C and 31D show examples of digital signage.

[0635] The digital signage 7300 shown in Figure 31C includes a housing 7301, a display unit 7000, and a speaker 7303, etc. Furthermore, it may include LED lamps, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc.

[0636] Figure 31D 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.

[0637] In Figures 31C and 31D, a display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0638] 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.

[0639] 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.

[0640] Furthermore, as shown in Figures 31C and 31D, it is preferable that the digital signage 7300 or digital signage 7400 can be linked wirelessly with an information terminal 7311 or information terminal 7411 such as 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 7311 or information terminal 7411. Also, the display on the display unit 7000 can be switched by operating the information terminal 7311 or information terminal 7411.

[0641] Furthermore, the digital signage 7300 or digital signage 7400 can be used to run games using the screen of the information terminal 7311 or information terminal 7411 as the control device (controller). This allows an unspecified number of users to participate in and enjoy the game simultaneously.

[0642] The electronic equipment shown in Figures 32A to 32G includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), connection terminals 9006, sensors 9007 (including functions for 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), a microphone 9008, etc.

[0643] In Figures 32A to 32G, a display device according to one embodiment of the present invention can be applied to the display unit 9001.

[0644] The electronic devices shown in Figures 32A to 32G have various functions. For example, they may have functions to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date or time, a function to control processing by various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. However, the functions of electronic devices are not limited to these and can have various functions. Electronic devices may have multiple display units. Furthermore, electronic devices may be equipped with a camera, etc., and have functions to capture still images or videos and save them to a recording medium (external or built into the camera), a function to display the captured images on a display unit, etc.

[0645] Details of the electronic equipment shown in Figures 32A to 32G will be explained below.

[0646] Figure 32A is a perspective view showing a personal digital assistant (PDA) 9101. The PDA 9101 can be used, for example, as a smartphone. The PDA 9101 may also be equipped with a speaker 9003, connection terminals 9006, sensors 9007, etc. The PDA 9101 can also display text and image information on multiple surfaces. Figure 32A shows an example where three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the subject of an email or SNS message, the sender's name, date and time, time, battery level, signal strength, etc. Alternatively, icons 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0647] Figure 32B is a perspective view showing the personal digital assistant (PDA) 9102. The PDA 9102 has the function of displaying information on three or more sides of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, a user can check information 9053, which is displayed in a position that can be observed from above the PDA 9102, while the PDA 9102 is stored in the breast pocket of their clothing. The user can check the display without taking the PDA 9102 out of their pocket and decide, for example, whether or not to answer a call.

[0648] Figure 32C is a perspective view showing the tablet terminal 9103. The tablet terminal 9103 can run various applications, such as mobile phone calls, email, document viewing and creation, music playback, internet communication, and computer games. The tablet terminal 9103 has a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the housing 9000. The left side of the housing 9000 has operation keys 9005 as buttons for operation, and the bottom has connection terminals 9006.

[0649] Figure 32D is a perspective view showing a wristwatch-type personal information terminal 9200. The personal information terminal 9200 can be used, for example, as a smartwatch (registered trademark). The display unit 9001 has a curved display surface, allowing it to display information along the curved surface. The personal information terminal 9200 can also make hands-free calls by communicating with, for example, a wireless communication headset. Furthermore, the personal information terminal 9200 can transmit data to other information terminals and be charged via a connection terminal 9006. Charging may be performed by wireless power supply.

[0650] Figures 32E to 32G are perspective views showing a foldable portable information terminal 9201. Figure 32E shows the portable information terminal 9201 in an unfolded state, Figure 32G shows it in a folded state, and Figure 32F shows a perspective view of the state in between, transitioning from one of Figures 32E or 32G to the other. The portable information terminal 9201 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state. The display unit 9001 of the portable information terminal 9201 is supported by three housings 9000 connected by a hinge 9055. For example, the display unit 9001 can be bent with a radius of curvature of 0.1 mm to 150 mm.

[0651] This embodiment can be combined with other embodiments as appropriate. [Explanation of symbols]

[0652] AL: wiring, CL: wiring, GL: wiring, IRS: sub-pixel, PS: sub-pixel, RL: wiring, SL: wiring, SLB: wiring, SLG: wiring, SLR: wiring, 10: display device, 11: display unit, 12: drive circuit unit, 13: drive circuit unit, 21B: sub-pixel, 21G: sub-pixel, 21R: sub-pixel, 21: pixel, 30: pixel, 100A: display device, 100B: display device, 100C: display device, 100D: display device, 100E: display device, 100: display device, 101: layer, 110a: sub-pixel, 110b: sub-pixel, 110c: sub-pixel, 110d: sub-pixel, 110: pixel, 111a: pixel Electrode, 111b: Pixel electrode, 111c: Pixel electrode, 111d: Pixel electrode, 111: Conductive film, 113a: First layer, 113b: Second layer, 113c: Third layer, 113d: Fourth layer, 113: Layer, 114: Fifth layer, 115: Common electrode, 117: Light-shielding layer, 118A: First sacrificial layer, 118a: First sacrificial layer, 118B: First sacrificial layer, 118b: First sacrificial layer, 118C: First sacrificial layer, 118c: First sacrificial layer, 119A: Second sacrificial layer, 119a: Second sacrificial layer, 119B: Second sacrificial layer, 119b: Second sacrificial layer, 119C: Second sacrificial layer, 119c: Second sacrificial layer, 120: substrate, 122: resin layer, 123: conductive layer, 124a: pixel, 124b: pixel, 125a: sidewall, 125A: insulating film, 125b: sidewall, 125B: insulating film, 125: sidewall, 126a: optical adjustment layer, 126b: optical adjustment layer, 126c: optical adjustment layer, 130a: light-emitting device, 130b: light-emitting device, 130c: light-emitting device, 130d: light-emitting device, 131: protective layer, 132: protective layer, 134: void, 140: connection part, 142: adhesive layer, 151: substrate, 152: substrate, 153: insulating layer, 162: display part, 164: circuit, 165: wiring , 166: conductive layer, 172: FPC, 173: IC, 181A: first light-emitting unit, 181a: first light-emitting unit, 181B: first light-emitting unit, 181b: first light-emitting unit, 181C: first light-emitting unit, 181c: first light-emitting unit, 181d: first light-emitting unit, 182A: charge generation layer, 182a: charge generation layer, 182B: charge generation layer, 182b: charge generation layer, 182C: charge generation layer, 182c: charge generation layer, 182d: charge generation layer, 183A: second light-emitting unit, 183a: second light-emitting unit, 183B: second light-emitting unit,183b: Second light-emitting unit, 183C: Second light-emitting unit, 183c: Second light-emitting unit, 183d: Second light-emitting unit, 190a: Resist mask, 190b: Resist mask, 190c: Resist mask, 201: Transistor, 204: Connector, 205: Transistor, 209: Transistor, 210: Transistor, 211: Insulating layer, 213: Insulating layer, 214: Insulating layer, 215: Insulating layer, 218: Insulating layer, 221: Conductive layer, 222a: Conductive layer, 222b: Conductive layer, 223: Conductive layer, 225: Insulating layer, 228: Region, 231i: Channel Formation region, 231n: Low resistance region, 231: Semiconductor layer, 240: Capacitance, 241: Conductive layer, 242: Connection layer, 243: Insulating layer, 245: Conductive layer, 251: Conductive layer, 252: Conductive layer, 254: Insulating layer, 255a: Insulating layer, 255b: Insulating layer, 256: Plug, 261: Insulating layer, 262: Insulating layer, 263: Insulating layer, 264: Insulating layer, 265: Insulating layer, 271: Plug, 274a: Conductive layer, 274b: Conductive layer, 274: Plug, 280: Display module, 281: Display section, 282: Circuit section, 283a: Pixel circuit, 283: Pixel circuit section, 284a: Pixel, 284: Image 285: Element part, 286: Terminal part, 290: Wiring part, 291: FPC, 292: Substrate, 301: Substrate, 310: Transistor, 311: Conductive layer, 312: Low resistance region, 313: Insulating layer, 314: Insulating layer, 315: Element isolation layer, 320: Transistor, 321: Semiconductor layer, 323: Insulating layer, 324: Conductive layer, 325: Conductive layer, 326: Insulating layer, 327: Conductive layer, 328: Insulating layer, 329: Insulating layer, 331: Substrate, 332: Insulating layer, 351: Substrate, 352: Finger, 353: Layer, 355: Functional layer, 357: Layer, 359: Substrate, 401: Substrate, 410a: Transistor ZISTA, 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, 500: Display device, 501: Electrode, 502: Electrode, 512B_1: Light-emitting unit512B_2: Light-emitting unit, 512B_3: Light-emitting unit, 512B_n: Light-emitting unit, 512G_1: Light-emitting unit, 512G_2: Light-emitting unit, 512G_3: Light-emitting unit, 512G_n: Light-emitting unit, 512Q_1: Light-emitting unit, 512Q_2: Light-emitting unit, 512Q_3: Light-emitting unit, 512Q_n: Light-emitting unit, 512R_1: Light-emitting unit, 512R_2: Light-emitting unit, 512R_3: Light-emitting unit, 512R_n: Light-emitting unit, 521: Layer, 522: Layer, 523B: Light-emitting layer, 523G: Light-emitting layer, 523Q_1: Light-emitting Layer, 523Q_2: Light-emitting layer, 523Q_3: Light-emitting layer, 523R: Light-emitting layer, 524: Layer, 525: Layer, 531: Charge generation layer, 550B: Light-emitting device, 550G: Light-emitting device, 550R: Light-emitting device, 550W: Light-emitting device, 700A: Electronic equipment, 700B: Electronic equipment, 721: Housing, 723: Mounting part, 727: Earphone part, 750: Earphone, 751: Display panel, 753: Optical component, 756: Display area, 757: Frame, 758: Nose pad, 800A: Electronic equipment, 800B: Electronic equipment, 820: Display unit, 821: Housing, 822: Communication unit, 8 23: Mounting unit, 824: Control unit, 825: Imaging unit, 827: Earphone unit, 832: Lens, 6500: Electronic equipment, 6501: Housing, 6502: Display unit, 6503: Power button, 6504: Button, 6505: Speaker, 6506: Microphone, 6507: Camera, 6508: Light source, 6510: Protective member, 6511: Display panel, 6512: Optical member, 6513: Touch sensor panel, 6515: FPC, 6516: IC, 6517: Printed circuit board, 6518: Battery, 7000: Display unit, 7100: Television device, 7101: Housing, 7103: Stand D, 7111: Remote control unit, 7200: Notebook personal computer, 7211: Enclosure, 7212: Keyboard, 7213: Pointing device, 7214: External connection port, 7300: Digital signage, 7301: Enclosure, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 9000: Enclosure, 9001: Display unit, 9002: Camera, 9003: Speaker, 9005: Operation keys, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 9050: Icon,9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9101: Mobile information terminal, 9102: Mobile information terminal, 9103: Tablet terminal, 9200: Mobile information terminal, 9201: Mobile information terminal,

Claims

1. Form an insulating layer, A conductive film is formed on the insulating layer, A first layer is formed on the conductive film. A first sacrificial layer is formed on the first layer described above. The first layer and the first sacrificial layer are processed to expose a portion of the conductive film. A second layer is formed on the first sacrificial layer and the conductive film. A second sacrificial layer is formed on the second layer described above. The second layer and the second sacrificial layer are processed to expose a portion of the conductive film. By processing the conductive film, a first pixel electrode overlapping the first sacrificial layer and a second pixel electrode overlapping the second sacrificial layer are formed. A first insulating film is formed covering at least the side surfaces of the first pixel electrode, the side surfaces of the second pixel electrode, the side surfaces of the first layer, the side surfaces of the second layer, the side surfaces and top surface of the first sacrificial layer, and the side surfaces and top surface of the second sacrificial layer. A second insulating film is formed on the first insulating film. By processing the first insulating film and the second insulating film, a first side wall and a second side wall on the first side wall are formed, covering at least the side surface of the first pixel electrode and the side surface of the first layer. Remove the first sacrificial layer and the second sacrificial layer, A method for manufacturing a display device, comprising forming a common electrode on the first layer and the second layer.

2. In claim 1, As the first sacrificial layer, a first sacrificial film and a second sacrificial film on the first sacrificial film are formed. After forming the first resist mask on the second sacrificial film, the second sacrificial film is processed using the first resist mask. Remove the first resist mask, The first sacrificial film is processed using the processed second sacrificial film as a hard mask. A method for manufacturing a display device, comprising using the processed first sacrificial film as a hard mask to process the first layer.

3. In claim 1 or 2, A method for manufacturing a display device, comprising processing the conductive film using the first sacrificial layer and the second sacrificial layer as a hard mask.

4. In any one of claims 1 to 3, The first layer comprises a first light-emitting unit, a charge-generating layer on the first light-emitting unit, and a second light-emitting unit on the charge-generating layer. A method for manufacturing a display device, wherein the first light-emitting unit and the second light-emitting unit each have a light-emitting layer that emits light of the same color.

5. In any one of claims 1 to 4, A method for manufacturing a display device, comprising forming a protective layer on the aforementioned common electrode.

6. In any one of claims 1 to 5, After removing the first sacrificial layer and the second sacrificial layer, a third layer is formed on the first layer and the second layer. A method for manufacturing a display device, comprising forming the common electrode on the third layer described above.

7. In any one of claims 1 to 6, A method for manufacturing a display device, comprising forming a recess in the insulating layer during the processing step of the conductive film.

Images