Display device, method for manufacturing a display device, display module, and electronic device.

Abstract

Provided is a display device that has a high definition or a high resolution. The display device has a first light-emitting element, a second light-emitting element, and a side wall. Each of the first and second light-emitting elements has a pixel electrode, a first light-emitting layer on the pixel electrode, an intermediate layer on the first light-emitting layer, a second light-emitting layer on the intermediate layer, and a common electrode on the second light-emitting layer. In other words, the first and second light-emitting elements can have a tandem structure. The pixel electrode, the first light-emitting layer, the intermediate layer, and the second light-emitting layer are provided separately for each light-emitting element. The first light-emitting element and the second light-emitting element are adjacent to each other, and the side wall is provided between the first light-emitting element and the second light-emitting element. The side wall is provided so as to cover at least part of a side surface of the pixel electrode.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a display device and a method for manufacturing the same. Another aspect of the present invention relates to a display module and an electronic 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, light-emitting devices having light-emitting elements have been developed. Light-emitting elements (also called light-emitting devices, EL elements, or EL devices) that utilize the electroluminescence (EL) phenomenon have features such as being easy to make thin and light, being able to respond quickly to input signals, and being able to be driven using a DC constant voltage power supply, and are being applied to display devices.

[0006] Patent Document 1 discloses a display device for VR using an organic EL element (also called an organic EL device). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2018 / 087625 [Overview of the project] [Problems that the invention aims to solve]

[0008] When manufacturing a display device having multiple organic EL elements, it is preferable to form the light-emitting layers of the organic EL elements in an island-like manner, that is, to separate them for each organic EL element. This suppresses the flow of current between two adjacent light-emitting units via one or more layers common to two adjacent light-emitting units, such as a hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, and intermediate layer (charge generation layer), even when all organic EL elements emit light of the same color, such as white light. Therefore, unintended light emission (also called crosstalk) from the organic EL elements can be suppressed. Consequently, the contrast of the image displayed on the display device can be increased, and a display device with high display quality can be realized.

[0009] When forming the light-emitting layer in an island shape, for example, a vacuum evaporation method using a metal mask (also referred to as a shadow mask) is used. However, during evaporation, the contour of the layer may become blurred and the thickness at the edges may become thin. That is, the thickness of the island-shaped light-emitting layer may vary depending on the location. Also, when manufacturing a large-sized, high-resolution, or high-definition display device, there is a concern that the yield may be low due to the low dimensional accuracy of the metal mask and deformation due to heat or the like.

[0010] In addition, when manufacturing a display device using a vacuum evaporation method with a metal mask, there is an issue that a plurality of production lines are required for the manufacturing equipment. For example, since it is necessary to clean the metal mask regularly, at least two or more production lines of manufacturing equipment need to be prepared, and since it is necessary to use the other production line while one production line is under maintenance, considering mass production, a plurality of production lines are required for the manufacturing equipment. Therefore, there is an issue that the initial investment for introducing the manufacturing equipment 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 highly reliable display device as one of the problems. One aspect of the present invention is to provide a low-cost display device as one of the problems. One aspect of the present invention is to provide a novel 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 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. One aspect of the present invention is to provide a method for manufacturing a novel display device as one of the problems.

[0013] Note that the description of these problems does not preclude 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 includes a first light-emitting element, a second light-emitting element, a first side wall, and a second side wall. The first light-emitting element includes a first pixel electrode, a first light-emitting layer on the first pixel electrode, a first intermediate layer on the first light-emitting layer, a second light-emitting layer on the first intermediate layer, and a common electrode on the second light-emitting layer. The second light-emitting element includes a second pixel electrode, a third light-emitting layer on the second pixel electrode, a second intermediate layer on the third light-emitting layer, a fourth light-emitting layer on the second intermediate layer, and a common electrode on the fourth light-emitting layer. The first light-emitting element and the second light-emitting element are adjacent to each other. The first side wall covers at least a part of the side surface of the first pixel electrode, and the second side wall covers at least a part of the side surface of the second pixel electrode.

[0015] Alternatively, in the above aspect, there may be a gap between the first side wall and the second side wall.

[0016] Alternatively, one aspect of the present invention comprises a first light-emitting element, a second light-emitting element, a first side wall, a second side wall, a third side wall, and a fourth side wall, wherein the first light-emitting element comprises a first pixel electrode, a first light-emitting layer on the first pixel electrode, a first intermediate layer on the first light-emitting layer, a second light-emitting layer on the first intermediate layer, and a common electrode on the second light-emitting layer, and the second light-emitting element comprises a second pixel electrode, a third light-emitting layer on the second pixel electrode, a second intermediate layer on the third light-emitting layer, and a fourth light-emitting layer on the second intermediate layer. A display device having a common electrode on a fourth light-emitting layer, wherein the first light-emitting element and the second light-emitting element are adjacent to each other, the first sidewall covers at least a portion of the side surface of the first pixel electrode, the side surfaces of the first and second light-emitting layers, and the side surface of the first intermediate layer, the second sidewall covers at least a portion of the side surface of the first sidewall, the third sidewall covers at least a portion of the side surface of the second pixel electrode, the side surfaces of the third and fourth light-emitting layers, and the side surface of the second intermediate layer, and the fourth sidewall covers at least a portion of the side surface of the third sidewall.

[0017] Alternatively, in the above embodiment, there may be a gap between the second side wall and the fourth side wall.

[0018] Alternatively, in the above embodiment, the second side wall may cover at least a portion of the upper surface of the first side wall, and the fourth side wall may cover at least a portion of the upper surface of the third side wall.

[0019] Alternatively, in the above embodiment, a protective layer may be provided on the common electrode, with a first colored layer on the protective layer having a region overlapping with the first and second light-emitting layers, and a second colored layer on the protective layer having a region overlapping with the third and fourth light-emitting layers, wherein the first and second colored layers have the function of transmitting light of different colors, the first and third light-emitting layers have the function of emitting light of the same color, and the second and fourth light-emitting layers have the function of emitting light of the same color.

[0020] Alternatively, in the above embodiment, a common layer may be provided between the second and fourth light-emitting layers and the common electrode, and the common layer may function as either an electron injection layer or a hole injection layer in the first and second light-emitting elements.

[0021] Alternatively, in the above embodiment, the first pixel electrode and the second pixel electrode may be provided on an insulating layer, the insulating layer having a first protrusion in the region overlapping with the first pixel electrode, and the insulating layer having a second protrusion in the region overlapping with the second pixel electrode.

[0022] A display module having a display device according to one aspect of the present invention and at least one of a connector and an integrated circuit is also an aspect of the present invention.

[0023] An electronic device comprising a display module according to one aspect of the present invention, and at least one of a housing, battery, camera, speaker, and microphone, is also according to one aspect of the present invention.

[0024] Alternatively, in one aspect of the present invention, an insulating layer is formed, a conductive film, a first light-emitting film, an interlayer, a second light-emitting film, and a sacrificial film are sequentially deposited on the insulating layer, and the sacrificial film, the second light-emitting film, the interlayer, the first light-emitting film, and the conductive film are etched to form a first pixel electrode and a second pixel electrode on the insulating layer, a first light-emitting layer on the first pixel electrode and a second light-emitting layer on the second pixel electrode, a first interlayer on the first light-emitting layer and a second interlayer on the second light-emitting layer, a third light-emitting layer on the first interlayer and a fourth light-emitting layer on the second interlayer, a first sacrificial layer on the third light-emitting layer, and This is a method for manufacturing a display device, comprising: forming a second sacrificial layer on a fourth light-emitting layer; depositing an insulating film that covers at least a portion of the sides of the first and second pixel electrodes, the sides of the first to fourth light-emitting layers, the sides of the first and second intermediate layers, and the sides and top surfaces of the first and second sacrificial layers; etching the insulating film to form a first sidewall that covers at least a portion of the side of the first pixel electrode and a second sidewall that covers at least a portion of the side of the second pixel electrode; removing the first and second sacrificial layers; and forming common electrodes on the third and fourth light-emitting layers.

[0025] Alternatively, in one aspect of the present invention, an insulating layer is formed, a conductive film, a first light-emitting film, an interlayer, a second light-emitting film, and a sacrificial film are sequentially deposited on the insulating layer, and the sacrificial film, the second light-emitting film, the interlayer, the first light-emitting film, and the conductive film are etched to form a first pixel electrode and a second pixel electrode on the insulating layer, a first light-emitting layer on the first pixel electrode and a second light-emitting layer on the second pixel electrode, a first interlayer on the first light-emitting layer and a second interlayer on the second light-emitting layer, a third light-emitting layer on the first interlayer and a fourth light-emitting layer on the second interlayer, a first sacrificial layer on the third light-emitting layer and a second sacrificial layer on the fourth light-emitting layer, and the sides of the first and second pixel electrodes and the first to fourth This is a method for manufacturing a display device, comprising: forming a first insulating film covering at least a portion of the side surface of the light-emitting layer, the side surfaces of the first and second intermediate layers, and the side surfaces and top surfaces of the first and second sacrificial layers; forming a second insulating film on the first insulating film; etching the first insulating film and the second insulating film to form a first side wall covering at least a portion of the side surface of the first pixel electrode, a second side wall covering at least a portion of the side surface of the second pixel electrode, a third side wall covering at least a portion of the side surface of the first side wall, and a fourth side wall covering at least a portion of the side surface of the second side wall; removing the first and second sacrificial layers; and forming common electrodes on the third light-emitting layer and the fourth light-emitting layer.

[0026] Alternatively, in the above embodiment, the conductive film may be etched using the first sacrificial layer and the second sacrificial layer as a mask.

[0027] Alternatively, in the above embodiment, a protective layer may be formed on the common electrode, and a first colored layer having a region overlapping with the first and third light-emitting layers, and a second colored layer having a region overlapping with the second and fourth light-emitting layers may be formed on the protective layer, and the first colored layer and the second colored layer may have the function of transmitting light of different colors.

[0028] Alternatively, in the above embodiment, after removing the first sacrificial layer and the second sacrificial layer, a common layer having the function of either an electron injection layer or a hole injection layer may be formed on the third light-emitting layer and the fourth light-emitting layer, and a common electrode may be formed on the common layer.

[0029] Alternatively, in the above embodiment, recesses may be formed in the insulating layer during the etching process of the conductive film. [Effects of the Invention]

[0030] 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-screen display device can be provided. According to one aspect of the present invention, a highly reliable display device can be provided. According to one aspect of the present invention, a low-cost display device can be provided. According to one aspect of the present invention, a novel display device can be provided.

[0031] 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-format 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. According to one aspect of the present invention, a method for manufacturing a novel display device can be provided.

[0032] 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]

[0033] Figure 1 is a top view showing an example of the configuration of a display device. Figures 2A to 2E are top views showing examples of the configuration of a display device. Figures 3A and 3B are cross-sectional views showing examples of the configuration of a display device. Figure 3C is a cross-sectional view showing an example of the configuration of a light-emitting unit. Figures 4A and 4B are cross-sectional views showing examples of the configuration of a display device. Figure 4C is a cross-sectional view showing an example of the configuration of a light-emitting unit. Figures 5A and 5B are cross-sectional views showing examples of the configuration of a display device. Figures 6A and 6B are cross-sectional views showing examples of the configuration of a display device. Figures 7A and 7B are cross-sectional views showing examples of the configuration of a display device. Figure 8 is a top view showing an example of the configuration of a display device. Figures 9A and 9B are cross-sectional views showing examples of the configuration of a display device. Figures 10A to 10F are top views showing examples of the configuration of a display device. Figures 11A to 11E are top views showing an example of a method for manufacturing a display device. Figures 12A to 12E are cross-sectional views showing an example of a method for manufacturing a display device. Figures 13A and 13B are cross-sectional views showing an example of a method for manufacturing a display device. Figures 14A and 14B are perspective views showing example configurations of display modules. Figure 15 is a cross-sectional view showing an example of the configuration of a display device. Figure 16 is a cross-sectional view showing an example of the configuration of a display device. Figure 17 is a cross-sectional view showing an example of the configuration of a display device. Figure 18 is a cross-sectional view showing an example of the configuration of a display device. Figure 19 is a cross-sectional view showing an example of the configuration of a display device. Figures 20A and 20B show examples of electronic devices. Figures 21A and 21B show examples of electronic devices. Figures 22A and 22B show examples of electronic devices. Figures 23A to 23D show examples of electronic devices. Figures 24A to 24F show examples of electronic devices. [Modes for carrying out the invention]

[0034] 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.

[0035] In the configuration of 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 hatch patterns are the same, and reference numerals may not be assigned.

[0036] 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.

[0037] 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."

[0038] 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 FMM may be referred to as MML (Metal Maskless) structured devices.

[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 described with reference to the drawings.

[0040] In a method for manufacturing a display device according to one aspect of the present invention, first, a conductive film is formed on an insulating layer. Next, a first layer having a first light-emitting film is formed on the conductive film. Next, an interlayer is formed on the first layer. Next, a second layer having a second light-emitting film is formed on the interlayer. After that, a sacrificial film is formed on the second layer.

[0041] Next, a resist mask is formed on the sacrificial layer using a method such as photolithography. Then, the sacrificial layer, the second layer, the interlayer, the first layer, and the conductive layer are etched using the resist mask. This forms the first pixel electrode on the insulating layer, the first light-emitting unit on the first pixel electrode, the first interlayer on the first light-emitting unit, the second light-emitting unit on the first interlayer, and the first sacrificial layer on the second light-emitting unit in an island-like manner. Additionally, the second pixel electrode on the insulating layer, the third light-emitting unit on the second pixel electrode, the second interlayer on the third light-emitting unit, the fourth light-emitting unit on the second interlayer, and the second sacrificial layer on the fourth light-emitting unit are also formed in an island-like manner. The first to fourth light-emitting units each have the first to fourth light-emitting layers.

[0042] Thus, in the method for manufacturing a display device according to one aspect of the present invention, island-shaped light-emitting units, etc., are not formed by a pattern on a metal mask, but are formed using a photolithography method or the like. 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, because the light-emitting units can be formed in an island shape, a display device with high contrast and high display quality can be realized. In addition, by providing a sacrificial layer on the light-emitting units, damage to the light-emitting units during the manufacturing process of the display device can be reduced. As a result, a highly reliable display device can be realized.

[0043] While it is difficult to reduce the distance between adjacent light-emitting elements to less than 10 μm using, for example, a metal mask formation method, the above method allows for reducing this distance to 3 μm or less, 2 μm or less, or even 1 μm or less.

[0044] Furthermore, the pattern of the light-emitting unit itself can be made extremely small compared to when a metal mask is used. Also, for example, when a metal mask is used to form the light-emitting unit, variations in thickness occur between the center and edges of the pattern, so the effective area that can be used as a light-emitting region is small relative to the total area of ​​the pattern. On the other hand, in the above manufacturing method, since a film deposited to a uniform thickness is etched, island-shaped light-emitting layers, etc., can be formed with a uniform thickness. Therefore, even with a fine pattern, almost the entire area can be used as a light-emitting region. As a result, a display device that combines high resolution and a high aperture ratio can be manufactured.

[0045] As described above, in one aspect of the present invention, the light-emitting element in the display device has a configuration in which two or more light-emitting units are stacked with an intermediate layer in between. In other words, the light-emitting element in one aspect of the present invention can have a tandem structure. In a tandem light-emitting element, for example, by making the colors of the light emitted by the two stacked light-emitting units complementary, the light-emitting element can emit white light. Therefore, by providing a colored layer in the region overlapping with the light-emitting element, the display device in one aspect of the present invention can, for example, display in full color.

[0046] Here, each of the first to fourth light-emitting units includes at least a light-emitting layer, and preferably consists of multiple layers. Specifically, it is preferable to have one or more layers on the light-emitting layer. By having other layers between the light-emitting layer and the sacrificial layer, it is possible to suppress the exposure of the light-emitting layer to the outermost surface during the manufacturing process of the display device, thereby reducing damage to the light-emitting layer. This can improve the reliability of the light-emitting element. For example, each of the first to fourth light-emitting units preferably has a carrier transport layer on the light-emitting layer in addition to the light-emitting layer.

[0047] It is not necessary to form all the layers constituting the light-emitting element in an island shape. In one embodiment of the present invention, a method for manufacturing a display device involves forming some of the layers constituting the light-emitting element in an island shape, then removing the sacrificial layer, and forming the remaining layers constituting the light-emitting element and a common electrode (also called an upper electrode) in common for each light-emitting element. For example, a carrier injection layer and a common electrode can be formed in common for each light-emitting element.

[0048] On the other hand, the carrier injection layer is often a relatively conductive layer within the light-emitting element. Therefore, there is a risk of the light-emitting element short-circuiting if the carrier injection layer comes into contact with the side surface of a layer formed in an island shape. Furthermore, even when the carrier injection layer is provided in an island shape and a common electrode is formed in common between the light-emitting elements, there is a risk of the light-emitting element short-circuiting if the common electrode comes into contact with the side surface of the light-emitting unit or the side surface of the pixel electrode.

[0049] Therefore, in one aspect of the present invention, a display device is provided with side walls (also called sidewalls, sidewall protective layers, sidewall insulating films, insulating layers, etc.) that cover the sides of the island-shaped layers.

[0050] This prevents the island-shaped layers from coming into contact with the carrier injection layer or common electrode. Therefore, it is possible to suppress short circuits in the light-emitting element and improve the reliability of the light-emitting element.

[0051] [Example of a display device configuration] Figure 1 is a top view showing an example configuration of a display device 100, which is a display device according to one aspect of the present invention. 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. One pixel 110 is composed of three subpixels: subpixel 110a, subpixel 110b, and subpixel 110c.

[0052] Figure 1 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.

[0053] Figure 1 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, there may be one or more connection portions 140.

[0054] In the display device 100 shown in Figure 1, a stripe array is applied as the arrangement of sub-pixels 110a, 110b, and 110c. Here, the arrangement of sub-pixels is not limited to a stripe array. For example, an S-stripe array, matrix array, delta array, Bayer array, pentile array, etc., can be applied.

[0055] Furthermore, the top surface shape of the 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 the sub-pixel corresponds to the top surface shape of the light-emitting region of the light-emitting element.

[0056] Figures 2A to 2C are top views showing examples of the configuration of a pixel 110, and are modified versions of the pixel 110 shown in Figure 1. The pixel 110 shown in Figure 2A has an S-stripe array applied to it. The pixel 110 shown in Figure 2A is composed of three subpixels: subpixel 110a, subpixel 110b, and subpixel 110c. For example, subpixel 110a may be a blue subpixel, subpixel 110b a red subpixel, and subpixel 110c a green subpixel.

[0057] The pixel 110 shown in Figure 2B 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 square or roughly 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 element. For example, sub-pixel 110a may be a green sub-pixel, sub-pixel 110b a red sub-pixel, and sub-pixel 110c a blue sub-pixel.

[0058] A Pentile array is applied to pixels 125a and 125b shown in Figure 2C. Figure 2C shows an example in which pixels 125a having subpixels 110a and 110b, and pixels 125b having subpixels 110b and 110c are arranged alternately. For example, subpixel 110a may be a blue subpixel, subpixel 110b a green subpixel, and subpixel 110c a red subpixel.

[0059] Figures 2D and 2E are top views showing examples of the configuration of pixels 125a and 125b. The display device 100 may have a configuration in which multiple pixels 125a and pixels 125b are arranged in a matrix, rather than having only one pixel 110.

[0060] Pixels 125a and 125b, shown in Figures 2D and 2E, have a delta array applied. Pixel 125a 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 125b has one subpixel (subpixel 110c) in the top row (1st row) and two subpixels (subpixels 110a and 110b) in the bottom row (2nd row).

[0061] Figure 2D shows an example where each subpixel has a roughly square top shape with rounded corners, and Figure 2E shows an example where each subpixel has a circular top shape.

[0062] In photolithography, the finer the etching pattern, the more significant the effects of light diffraction become. This compromises the fidelity of transferring the photomask pattern through exposure, making it difficult to etch the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, patterns with rounded corners are likely to form. Consequently, the top surface shape of subpixels may be a polygon with rounded corners, an ellipse, or a circle.

[0063] Furthermore, in a method for manufacturing a display device according to one aspect of the present invention, a light-emitting unit having a light-emitting layer is etched in an island-like manner using a resist mask. The resist film formed on the light-emitting unit needs to be cured at a temperature lower than the heat resistance temperature of the light-emitting unit. Therefore, depending on the heat resistance temperature of the material of the light-emitting unit 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 on a shape that deviates from the desired shape during etching. As a result, the top surface shape of the light-emitting unit 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 light-emitting unit.

[0064] Furthermore, in order to achieve the desired shape of the top surface of the light-emitting unit, etc., 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.

[0065] 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 element is formed, a bottom-emission type that emits light toward the substrate on which the light-emitting element is formed, or a dual-emission type that emits light on both sides.

[0066] Figure 3A is a cross-sectional view showing an example of the configuration between the dashed-dotted line X1 and X2 in Figure 1.

[0067] As shown in Figure 3A, the display device 100 has light-emitting elements 130 provided on a layer 101 containing transistors, and protective layers 131 and 132 are provided to cover these light-emitting elements. A colored layer 133 (colored layer 133a, colored layer 133b, and colored layer 133c) is provided on the protective layer 132. The substrate 120 is bonded to the colored layer 133 by a resin layer 119. In addition, side walls 121 are provided in the region between adjacent light-emitting elements 130.

[0068] For example, a laminated structure can be applied to the transistor-containing layer 101, in which multiple transistors are provided on a substrate and an insulating layer is provided to cover these transistors. The transistor-containing layer 101 may have recesses between adjacent light-emitting elements 130. That is, the transistor-containing layer 101 may have protrusions in the region overlapping with the light-emitting elements 130. For example, the insulating layer located on the outermost surface of the transistor-containing layer 101 may have the above-mentioned recesses and protrusions. An example of the configuration of the transistor-containing layer 101 will be described later in Embodiment 2.

[0069] The light-emitting element 130 has, for example, the function of emitting white light. In this specification, a light-emitting element that has the function of emitting white light may be referred to as a white light-emitting element. A display device having a white light-emitting element can be used to display in full color by combining it with a colored layer (also called a color filter).

[0070] The light-emitting element 130 has a light-emitting unit 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 element, one electrode functions as the anode and the other as the cathode. In the following explanation, unless otherwise specified, the example will be one where the pixel electrode functions as the anode and the common electrode functions as the cathode.

[0072] The light-emitting element 130 includes a pixel electrode 111 on a layer 101 containing a transistor, a light-emitting unit 112_1 on the pixel electrode 111, an intermediate layer 113 on the light-emitting unit 112_1, a light-emitting unit 112_2 on the intermediate layer 113, a common layer 114 on the light-emitting unit 112_2, and a common electrode 115 on the common layer 114. Here, the common layer 114 can be, for example, a layer containing a material with high electron injection properties (electron injection layer). Note that if the pixel electrode 111 functions as a cathode and the common electrode 115 functions as an anode, the common layer 114 can be, for example, a hole injection layer.

[0073] The pixel electrodes 111, light-emitting units 112, and intermediate layer 113 are formed in an island-like manner for each light-emitting element 130. In other words, the pixel electrodes 111, light-emitting units 112, and intermediate layer 113 are provided separately for each light-emitting element 130. Due to the formation of the pixel electrodes 111, etc., the layer 101 containing the transistor can have a protrusion in the region overlapping with the pixel electrodes 111. The light-emitting unit 112_1, the intermediate layer 113, and the light-emitting unit 112_2 can be collectively referred to as layer 103a.

[0074] In this specification, etc., different light-emitting units 112 are denoted with symbols such as _1, _2, etc., to distinguish them. Similar notations may be used for other elements.

[0075] Of the pixel electrodes 111 and the common electrode 115, the electrode that extracts light preferably uses 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.

[0076] As the material for forming the pair of electrodes (pixel electrode 111 and common electrode 115) of the light-emitting element 130, 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), and silver, palladium, and copper alloys (Ag-Pd-Cu, also written as APC). In addition, metals such as aluminum (Al), 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, etc., can also be used.

[0077] It is preferable that the light-emitting element 130 has a microcavity structure. Therefore, it is preferable that one of the pair of electrodes of the light-emitting element 130 has an electrode that is transparent to and reflective to visible light (a semi-transmissive / semi-reflective electrode), and the other electrode has an electrode that is reflective to visible light (a reflective electrode). By having a microcavity structure in the light-emitting element 130, the light emitted from the light-emitting unit 112 can be resonated between the two electrodes, thereby strengthening the light emitted from the light-emitting element 130.

[0078] 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).

[0079] 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 element 130 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.

[0080] Figure 3B is a cross-sectional view showing an example of the configuration between the dashed-dotted line Y1-Y2 in Figure 1, and is a cross-sectional view showing an example of the configuration of the connection portion 140. The connection portion 140 includes a connection electrode 111C on the layer 101 containing the transistor, a common electrode 115 on the connection electrode 111C, a protective layer 131 on the common electrode 115, a protective layer 132 on the protective layer 131, a resin layer 119 on the protective layer 132, and a substrate 120 on the resin layer 119. The connection electrode 111C is electrically connected to the common electrode 115.

[0081] Figure 3C is a cross-sectional view showing a detailed configuration example of layer 103a. Light-emitting unit 112_1 includes, for example, layer 181, layer 182 on layer 181, light-emitting layer 183_1 on layer 182, and layer 184 on light-emitting layer 183_1. Light-emitting unit 112_2 includes, for example, layer 182 on intermediate layer 113, light-emitting layer 183_2 on layer 182, and layer 184 on light-emitting layer 183_2.

[0082] Layer 181 has, for example, a layer containing a material with high hole injection properties (hole injection layer). Layer 182 has, for example, a layer containing a material with high hole transport properties (hole transport layer). Layer 184 has, for example, a layer containing a material with high electron transport properties (electron transport layer). Here, when the pixel electrode 111 functions as a cathode and the common electrode 115 functions as an anode, layer 181 has an electron injection layer, etc. Also, layer 182 has an electron transport layer, etc. Furthermore, layer 184 has a hole transport layer, etc. The light-emitting unit 112 may have a layer containing a material with high hole blocking properties (hole blocking layer), or a layer containing a material with high electron blocking properties (electron blocking layer).

[0083] Layers 182 and 184, etc., may have the same configuration (material, film thickness, etc.) in, for example, light-emitting unit 112_1 and light-emitting unit 112_2, or they may have different configurations.

[0084] In Figure 3C, layers 181 and 182 are shown separately, but this is not the only way to represent them. For example, if layer 181 has the functions of both a hole injection layer and a hole transport layer, or if layer 181 has the functions of both an electron injection layer and an electron transport layer, then layer 182 may be omitted.

[0085] By providing layer 184 on the light-emitting layer 183_2, exposure of the light-emitting layer 183 to the outermost surface during the manufacturing process of the display device 100 can be suppressed, thereby reducing damage to the light-emitting layer 183. This improves the reliability of the light-emitting element 130.

[0086] The intermediate layer 113 has the function of injecting electrons into one of the light-emitting units 112_1 and 112_2, and holes into the other, when a voltage is applied between the pixel electrode 111 and the common electrode 115. The intermediate layer 113 can also be called a charge generation layer.

[0087] The color of the light emitted by the light-emitting layer 183_1 and the color of the light emitted by the light-emitting layer 183_2 can be, for example, complementary colors. This allows the light-emitting element 130 to emit white light as a whole. For example, one of the light-emitting layer 183_1 or light-emitting layer 183_2 may emit red light and green light, while the other light-emitting layer 183_1 or light-emitting layer 183_2 may emit blue light. Alternatively, one of the light-emitting layer 183_1 or light-emitting layer 183_2 may emit yellow light or orange light, while the other light-emitting layer 183_1 or light-emitting layer 183_2 may emit blue light. Here, if one light-emitting layer 183 emits two or more colors of light, the light-emitting layer 183 can be configured as a stack of two or more layers. For example, if one light-emitting layer 183 emits red light and green light, the light-emitting layer 183 can be configured as a stack of a layer that emits red light and a layer that emits green light.

[0088] In this specification, a configuration in which multiple light-emitting units 112 are stacked via an intermediate layer 113, as in the light-emitting element 130, is called a tandem structure. On the other hand, a configuration having one light-emitting unit 112 between a pair of electrodes is called a single structure. The tandem structure can also be called, for example, a stacked structure. By using a tandem structure for the light-emitting element, it is possible to create a light-emitting element that can emit high brightness. Furthermore, compared to a single structure, the tandem structure can reduce the current required to obtain the same brightness, thereby reducing the power consumption of the display device and improving the reliability of the light-emitting element.

[0089] Furthermore, a structure in which the light-emitting layer is separated for each light-emitting element, such as in the light-emitting element 130, is sometimes called an SBS (Side By Side) structure. The SBS structure allows for the optimization of materials and configurations for each light-emitting element, thus increasing the freedom in selecting materials and configurations and making it easier to improve the brightness and reliability of the light-emitting elements.

[0090] The light-emitting element 130 can be said to have both a tandem structure and an SBS structure. Therefore, it can combine the advantages of both a tandem structure and an SBS structure. Furthermore, as shown in Figure 3A, the display device 100 has a structure in which the light-emitting units 112 are formed in series in two stages, so it can also be called a two-stage tandem structure.

[0091] Here, the light-emitting element 130 is a white light-emitting element. In other words, the color emitted by the light-emitting element 130 is not made different depending on the color exhibited by the sub-pixel. Therefore, the color emitted by the light-emitting layer 183 does not need to be different for each light-emitting element 130. Thus, for example, the light-emitting layer 183 that all the light-emitting elements 130 have can be formed at once. Consequently, the display device 100 can be manufactured at a lower cost and have a higher yield than when the color emitted by the light-emitting layer 183 is made different depending on the color exhibited by the sub-pixel. Thus, the price of the display device 100 can be reduced.

[0092] The following describes specific examples of each layer of the light-emitting element 130.

[0093] 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).

[0094] 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.

[0095] 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.

[0096] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer, and is a layer containing a material with high electron injection capabilities. Alkali metals, alkaline earth metals, or compounds thereof can be used as materials with high electron injection capabilities. Composite materials containing both electron transport materials and donor materials (electron-donating materials) can also be used as materials with high electron injection capabilities.

[0097] 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 xAlkali 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.

[0098] Alternatively, an electron-transporting material may be used as the electron injection layer described above. 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.

[0099] 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.

[0100] 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. Compared to BPhen, NBPhen has a higher glass transition temperature (Tg) and superior heat resistance.

[0101] 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.

[0102] Examples of luminescent materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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 material (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 material, 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 element.

[0107] As the intermediate layer, for example, a material applicable to the electron injection layer, such as lithium, can be suitably used. Alternatively, as the intermediate layer, a material applicable to the hole injection layer can be suitably used. Furthermore, the intermediate layer can include a layer containing a hole transport material and an acceptor material (electron-accepting material). Alternatively, the intermediate layer can include a layer containing an electron transport material and a donor material. By forming an intermediate layer having such a layer, the increase in the driving voltage when light-emitting units are stacked can be suppressed.

[0108] At least a portion of the side surface of the pixel electrode 111 is covered by the side wall 121. This prevents the common layer 114 from coming into contact with the side surface of the pixel electrode 111. In addition, at least a portion of the side surface of the light-emitting unit 112 and the side surface of the intermediate layer 113 may also be covered by the side wall 121. This prevents the common layer 114 from coming into contact with either the side surface of the light-emitting unit 112 or the intermediate layer 113. As a result, short circuits of the light-emitting element 130 can be suppressed.

[0109] Figures 3A and 3B show an example in which the side wall 121 has a two-layer structure consisting of side wall 121a and side wall 121b. The thickness of side wall 121b in the X direction and the thickness in the Y direction can be made thicker than the thickness of side wall 121a in the X direction and the thickness in the Y direction. In addition, the shape of the end of side wall 121b can be rounded. Rounding the shape of the end of side wall 121b is preferable because it improves the coverage of the common layer 114, the common electrode 115, and the protective layer 131.

[0110] The side wall 121a covers at least a portion of the side surface of the pixel electrode 111. The side wall 121a may also cover at least a portion of the side surface of the light-emitting unit 112 and the intermediate layer 113. The side wall 121b covers at least a portion of the side surface of the side wall 121a and the upper surface of the side wall 121a.

[0111] For side walls 121a and 121b, 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.

[0112] The side walls 121a and 121b can be formed by various film deposition methods, such as sputtering, vapor deposition, chemical vapor deposition (CVD), and atomic layer deposition (ALD). In particular, since the ALD method causes little damage to the layer to be formed, it is preferable to form the side walls 121a, which are formed directly on the light-emitting unit 112 and the intermediate layer 113, using the ALD method. Furthermore, it is preferable to form the side walls 121b by sputtering in this case, as this can increase productivity.

[0113] For example, an aluminum oxide film formed by the ALD method can be used on the side wall 121a, and a silicon nitride film formed by the sputtering method can be used on the side wall 121b.

[0114] Furthermore, it is preferable that one or both of the sidewalls 121a and 121b function as a barrier insulating film against at least one of water and oxygen. Alternatively, it is preferable that one or both of the sidewalls 121a and 121b 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 sidewalls 121a and 121b have a function to capture or fix (also called gettering) at least one of water and oxygen.

[0115] 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).

[0116] One or both of the side walls 121a and 121b have the function of the barrier insulating film or gettering function described above, thereby suppressing the intrusion of impurities (typically water or oxygen) that can diffuse from the outside into each light-emitting element. This configuration makes it possible to provide a display device with excellent reliability.

[0117] Air gaps 134 may be formed in the region between the light-emitting elements 130 (between the side walls 121) and in the recesses of the layer 101 containing the transistors. Figure 3A shows an example in which an air gap 134 is formed between the layer 101 containing the transistors and the common layer 114. Note that depending on the distance between adjacent light-emitting elements 130, the thickness of the common layer 114, the thickness of the common electrode 115, and the thickness of the protective layer 131, an air gap 134 may not be formed. In this case, the space between adjacent light-emitting elements 130 is filled with at least one of the common layer 114, the common electrode 115, and the protective layer 131. Alternatively, an insulating material may be filled into the region that could become an air gap.

[0118] The void 134 contains one or more of the following: air, nitrogen, oxygen, carbon dioxide, and Group 18 elements (typically helium, neon, argon, xenon, krypton, etc.). The void may also contain gases used during film formation, such as the common layer 114. For example, when forming the common layer 114 by vacuum deposition, the void may be in a reduced-pressure atmosphere. If the void 134 contains gas, the gas can be identified by gas chromatography or other methods.

[0119] Furthermore, if the refractive index of the air gap 134 is lower than that of the side wall 121, the light emitted from the light-emitting unit 112 is reflected at the interface between the side wall 121 and the air gap 134. This suppresses the incidence of light emitted from the light-emitting unit 112 on adjacent pixels (or sub-pixels). This suppresses the mixing of light of different colors, thereby improving the display quality of the display device.

[0120] 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.

[0121] Examples of organic insulating materials include acrylic resins, epoxy resins, polyimide resins, polyamide resins, polyimidoamide resins, polysiloxane resins, benzocyclobutene resins, and phenolic resins. Various resins suitable for the resin layer 119 may also be used.

[0122] 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 layer 131 and protective layer 132 may be used.

[0123] Thus, the shape of the layer formed after the side wall 121 is formed can vary depending on the material, film deposition method, and film thickness, and is not particularly limited. One embodiment of the present invention is a display device in which short circuits of the light-emitting element 130 are suppressed by having the side wall 121. Therefore, the range of selection for the material, film deposition method, and film thickness of the layer formed after the side wall 121 can be broadened.

[0124] The display device 100 preferably has a protective layer 131 and a protective layer 132 on the light-emitting element 130. Providing the protective layer 131 and protective layer 132 can improve the reliability of the light-emitting element 130. However, the display device 100 does not necessarily have to have the protective layer 131 or the protective layer 132.

[0125] The conductivity of 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 protective layers 131 and 132.

[0126] The presence of inorganic films in protective layers 131 and 132 suppresses oxidation of the common electrode 115 and prevents impurities (such as moisture and oxygen) from entering the light-emitting element 130. Therefore, degradation of the light-emitting element 130 is suppressed, and the reliability of the display device can be improved.

[0127] For 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.

[0128] 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.

[0129] The protective layer 131 and the protective layer 132 each preferably have a nitride insulating film or a nitride oxide insulating film, and more preferably have a nitride insulating film.

[0130] 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.

[0131] When the light emitted from the light-emitting element 130 is extracted via protective layers 131 and 132, it is preferable that 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.

[0132] For example, the 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 this laminated structure, impurities (water, oxygen, etc.) entering the light-emitting unit 112 can be suppressed.

[0133] Furthermore, protective layers 131 and 132 may have organic films. For example, protective layer 132 may have both an organic film and an inorganic film.

[0134] Different film deposition methods may be used for protective layer 131 and protective layer 132. Specifically, protective layer 131 may be formed using the ALD method and protective layer 132 may be formed using the sputtering method.

[0135] A colored layer 133 is provided on the protective layer 132. The colored layer 133 has an area that overlaps with the light-emitting element 130. Specifically, it has an area that overlaps with the light-emitting layer 183. Figure 3A shows an example in which a different colored layer 133 (colored layer 133a, colored layer 133b, or colored layer 133c) is provided for each light-emitting element 130. The colored layers 133a, 133b, and 133c have the function of transmitting light of different colors from each other. For example, colored layer 133a has the function of transmitting red light, colored layer 133b has the function of transmitting green light, and colored layer 133c has the function of transmitting blue light. As a result, the display device 100 can display in full color. Note that the colored layers 133a, 133b, and 133c may also have the function of transmitting cyan, magenta, or yellow light.

[0136] Here, it is preferable that adjacent colored layers 133 have overlapping regions. Specifically, it is preferable that adjacent colored layers 133 have overlapping regions in regions that do not overlap with the light-emitting unit 112. By overlapping colored layers 133 that transmit light of different colors, the colored layers 133 can function as light-shielding layers in the overlapping regions. Therefore, it is possible to suppress the leakage of light emitted by the light-emitting element 130 to adjacent sub-pixels. For example, it is possible to suppress the incidence of light emitted by the light-emitting element 130 that overlaps with colored layer 133a onto colored layer 133b. Therefore, the contrast of the image displayed on the display device can be increased, and a display device with high display quality can be realized.

[0137] It is not necessary for adjacent colored layers 133 to have overlapping regions. In this case, it is preferable to provide a light-shielding layer in a region that does not overlap with the light-emitting unit 112. The light-shielding layer can be provided, for example, on the side of the substrate 120 facing the resin layer 119. Alternatively, the colored layer 133 may be provided on the side of the substrate 120 facing the resin layer 119.

[0138] The upper edge of the pixel electrode 111 is not covered by an insulating layer. Therefore, the distance between adjacent light-emitting elements 130 can be made extremely narrow. Consequently, a high-definition or high-resolution display device can be made.

[0139] The display device 100 can reduce the distance between the light-emitting elements 130. Specifically, the distance between the light-emitting elements 130 can be 1 μm or less, preferably 500 nm or less, more preferably 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, for example, there is a region where the distance between the side surface of the light-emitting unit 112 of one light-emitting element 130 and the side surface of the light-emitting unit 112 of an adjacent light-emitting element 130 is 1 μm or less, preferably a region where the distance is 0.5 μm (500 nm) or less, and more preferably a region where the distance is 100 nm or less.

[0140] In this specification, adjacent elements do not necessarily have to be in contact with each other. For example, the light-emitting units 112 of adjacent light-emitting elements 130 are not in contact with each other, but two light-emitting units 112 are adjacent to each other.

[0141] Various optical components can 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-gathering films. In addition, 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 be placed on the outside of the substrate 120.

[0142] 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 element should be made of a material that transmits the light. Using a flexible material for the substrate 120 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used as the substrate 120.

[0143] As the substrate 120, various materials can be used, including 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. Glass with a thickness sufficient to provide flexibility may also be used for the substrate 120.

[0144] 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).

[0145] 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.

[0146] 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.

[0147] 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.

[0148] As the resin layer 119, 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.

[0149] 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.

[0150] 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 for conductive layers of various wirings and electrodes that constitute a display device, and for conductive layers of light-emitting elements (conductive layers that function as pixel electrodes or common electrodes).

[0151] 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.

[0152] Figure 3A shows an example in which two light-emitting units 112 are stacked, but the present invention is not limited to this. Figure 4A is a cross-sectional view showing an example of the configuration between the dashed-dotted lines X1 and X2 in Figure 1 when three light-emitting units 112 are stacked, and Figure 4B is a cross-sectional view showing an example of the configuration between the dashed-dotted lines Y1 and Y2 in Figure 1.

[0153] In the example shown in Figure 4A, the light-emitting element 130 includes a pixel electrode 111 on a layer 101 containing a transistor, a light-emitting unit 112_1 on the pixel electrode 111, an intermediate layer 113_1 on the light-emitting unit 112_1, a light-emitting unit 112_2 on the intermediate layer 113_1, an intermediate layer 113_2 on the light-emitting unit 112_2, a light-emitting unit 112_3 on the intermediate layer 113_2, a common layer 114 on the light-emitting unit 112_3, and a common electrode 115 on the common layer 114. In the example shown in Figure 4A, since the structure consists of three stacked light-emitting units 112, it can be called a three-stage tandem structure. Here, the light-emitting units 112_1 to 112_3 and the intermediate layers 113_1 and 113_2 can be collectively referred to as layer 103b.

[0154] Figure 4C is a cross-sectional view showing a detailed configuration example of layer 103b. The light-emitting unit 112_3 includes, for example, layer 182 on the intermediate layer 113_2, light-emitting layer 183_3 on layer 182, and layer 184 on the light-emitting layer 183_3.

[0155] Each of the light-emitting layers 183_1 to 183_3 can emit, for example, red light, green light, or blue light. For example, light-emitting layer 183_1 can emit red light, light-emitting layer 183_2 can emit green light, and light-emitting layer 183_3 can emit blue light. Alternatively, light-emitting layer 183_1 can emit blue light, light-emitting layer 183_2 can emit yellow light, yellow-green light, or green light, and light-emitting layer 183_3 can emit blue light. Furthermore, light-emitting layer 183_1 can emit blue light, light-emitting layer 183_2 can emit red light and yellow, yellow-green, or green light, and light-emitting layer 183_3 can emit blue light.

[0156] Furthermore, the light-emitting element 130 may have a structure in which four or more light-emitting units 112 are stacked. In other words, the light-emitting element 130 may have a tandem structure of four or more stages.

[0157] In this way, by increasing the number of stacked light-emitting units 112, the brightness obtained from the light-emitting element 130 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 112, the current required to obtain the same brightness can be reduced, thus reducing the power consumption of the light-emitting element 130 in proportion to the number of stacks.

[0158] Figure 5A is a cross-sectional view showing an example of the configuration between the dashed lines X1 and X2 in Figure 1, and Figure 5B is a cross-sectional view showing an example of the configuration between the dashed lines Y1 and Y2 in Figure 1. Figures 5A and 5B are modified examples of the configurations shown in Figures 3A and 3B, differing in that the side wall 121 has a single-layer structure. In the configurations shown in Figures 5A and 5B, the side wall 121 can be made of the same material as, for example, the side wall 121a and can be formed in the same way as the side wall 121a. For example, an aluminum oxide film formed by the ALD method can be used as the side wall 121 shown in Figures 5A and 5B.

[0159] By configuring the display device 100 as shown in Figures 5A and 5B, the manufacturing process for the side wall 121 can be simplified, reducing the number of manufacturing steps for the display device 100. This allows the display device 100 to be manufactured at a lower cost and has a higher yield. Therefore, the price of the display device 100 can be reduced.

[0160] Figure 6A is a cross-sectional view showing an example configuration between the dashed-dotted lines X1 and X2 in Figure 1, and Figure 6B is a cross-sectional view showing an example configuration between the dashed-dotted lines Y1 and Y2 in Figure 1. Figures 6A and 6B are modified examples of the configurations shown in Figures 3A and 3B, and differ from the display device 100 shown in Figures 3A and 3B in that the light-emitting element 130 has a layer 114a instead of a common layer 114.

[0161] Layer 114a, like the common layer 114, may have, for example, an electron injection layer. Furthermore, if the pixel electrode 111 functions as the cathode and the common electrode 115 functions as the anode, layer 114a may have, for example, a hole injection layer.

[0162] Layer 114a is formed in an island-like manner for each light-emitting element 130, similar to the pixel electrode 111, the light-emitting unit 112, and the intermediate layer 113. In other words, layer 114a is provided separately for each light-emitting element 130.

[0163] Figure 7A is a cross-sectional view showing an example of the configuration between the dashed-dotted lines X1 and X2 in Figure 1, and Figure 7B is a cross-sectional view showing an example of the configuration between the dashed-dotted lines Y1 and Y2 in Figure 1. Figures 7A and 7B are modified examples of the configurations shown in Figures 3A and 3B, showing an example in which no gap 134 is formed between adjacent light-emitting elements 130, and a common layer 114 is filled. In addition to the common layer 114, a common electrode 115 may also be filled between adjacent light-emitting elements 130. Furthermore, a protective layer 131 may also be filled. In cases where the distance between adjacent light-emitting elements 130 is long, the gap 134 may not be formed as shown in Figure 7A.

[0164] Since the display device 100 has side walls 121, even if a common layer 114 or the like is filled between adjacent light-emitting elements 130 as shown in Figure 7A, it is possible to suppress the common layer 114 from coming into contact with any of the side surfaces of the pixel electrodes 111, light-emitting units 112, and intermediate layer 113. Therefore, even if a common layer 114 or the like is filled between adjacent light-emitting elements 130, short circuits of the light-emitting elements 130 can be suppressed.

[0165] Figure 1 shows an example in which pixel 110 is composed of three subpixels, subpixel 110a, subpixel 110b, and subpixel 110c, but the present invention is not limited to this. Figure 8 is a top view showing an example of the configuration of the display device 100.

[0166] The pixel 110 shown in Figure 8 is composed of four subpixels: subpixel 110a, subpixel 110b, subpixel 110c, and subpixel 110d. Subpixels 110a, 110b, 110c, and 110d can be subpixels of different colors. For example, subpixels 110a, 110b, and 110c can be red, green, and blue, respectively, and subpixel 110d can be a white subpixel.

[0167] Figure 8 shows an example where each subpixel is arranged in a 2x3 grid within a single pixel 110. 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.

[0168] Figure 9A is a cross-sectional view showing an example of the configuration between the dashed-dotted lines X3 and X4 in Figure 8. Figure 9B is a cross-sectional view showing an example of the configuration between the dashed-dotted lines Y3 and Y4 in Figure 8, and is a cross-sectional view showing an example of the configuration of the connection part 140.

[0169] If the light-emitting element 130 has the function of emitting white light, the sub-pixels without the colored layer 133 can be made into white sub-pixels.

[0170] Figures 10A to 10F are top views showing an example configuration of a pixel 110 having sub-pixels 110a, 110b, 110c, and 110d, and are modified versions of the pixel 110 shown in Figure 8.

[0171] The pixels 110 shown in Figures 10A to 10C are arranged in a stripe pattern. The pixels 110 shown in Figures 10D to 10F are arranged in a matrix pattern.

[0172] Figure 10A shows an example where each subpixel has a rectangular top surface shape, Figure 10B shows an example where each subpixel has a top surface shape formed by connecting two semicircles and a rectangle, and Figure 10C shows an example where each subpixel has an elliptical top surface shape. Furthermore, Figure 10D shows an example where each subpixel has a square top surface shape, Figure 10E shows an example where each subpixel has a roughly square top surface shape with rounded corners, and Figure 10F shows an example where each subpixel has a circular top surface shape.

[0173] [An example of a method for manufacturing a display device] Next, an example of a method for manufacturing the display device 100 will be described. Specifically, an example of a method for manufacturing the display device 100 shown in Figures 1, 3A, and 3B will be described.

[0174] Figures 11A to 11E, 12A to 12E, 13A, and 13B are cross-sectional views showing an example of a method for manufacturing the display device 100, and show side by side the cross-sectional view between the dashed lines X1-X2 and the cross-sectional view between Y1-Y2 in Figure 1.

[0175] Thin films (insulating films, semiconductor films, and conductive films, etc.) that constitute display devices can be formed using sputtering, 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).

[0176] 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.

[0177] 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 (hole injection layers, hole transport layers, light-emitting layers, electron transport layers, etc.) included in the light-emitting unit 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.).

[0178] Furthermore, when processing the thin film that constitutes the display device, it can be processed using methods such as photolithography. Alternatively, the thin film may be processed by nanoimprint lithography, sandblasting, or lift-off methods. In addition, island-shaped thin films may be directly formed by a film deposition method using a shielding mask such as a metal mask.

[0179] 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.

[0180] 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 for exposure. An electron beam can also be used instead of light for exposure. 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.

[0181] For processing thin films, methods such as dry etching, wet etching, and sandblasting can be used.

[0182] To fabricate the display device 100, first, a layer 101 containing transistors is formed. As mentioned above, the outermost surface of the layer 101 containing transistors can be an insulating layer. Next, a conductive film 111A, which will later become the pixel electrode 111 and the connecting electrode 111C, is deposited on the layer 101 containing transistors.

[0183] Next, a layer 112_1A, which will become the light-emitting unit 112_1, is formed on the conductive film 111A. Specifically, a film that will later become layer 181, a film that will later become layer 182, a light-emitting film that will later become the light-emitting layer 183_1, and a film that will later become layer 184 are formed in order. After that, an intermediate film 113A, which will later become the intermediate layer 113, is formed on layer 112_1A.

[0184] Next, a layer 112_2A, which will become the light-emitting unit 112_2, is formed on the interlayer 113A. Specifically, a film that will later become layer 182, a light-emitting film that will later become the light-emitting layer 183_2, and a film that will later become layer 184 are deposited in sequence.

[0185] The film on layer 112_1A, the interlayer 113A, and the film on layer 112_2A can be formed by, for example, vapor deposition, sputtering, or inkjet. However, the film formation methods described above can be used as appropriate.

[0186] It is preferable that layer 112_1A, interlayer 113A, and layer 112_2A are not provided on the connection portion 140. For example, when the film of layer 112_1A, the interlayer 113A, and the film of layer 112_2A are formed by vapor deposition (or sputtering), it is preferable to use a shielding mask so that these films are not formed on the connection portion 140.

[0187] Next, a sacrificial film 141 is formed on layer 112_2A. The sacrificial film 141 is also provided on the connecting portion 140.

[0188] The sacrificial film 141 can be a film that has high resistance to etching of the film on layer 112_2A, the interlayer 113A, and the film on layer 112_1A, i.e., a film with a high etching selectivity ratio. Furthermore, the sacrificial film 141 can be a film with a high etching selectivity ratio with respect to protective films such as the protective film 143 described later. In addition, the sacrificial film 141 can be a film that can be removed by a wet etching method that causes minimal damage to the film on layer 112_2A, the interlayer 113A, and the film on layer 112_1A.

[0189] As the sacrificial film 141, for example, a metal film, alloy film, metal oxide film, semiconductor film, inorganic insulating film, or other inorganic film can be used. The sacrificial film 141 can be formed by various film deposition methods such as sputtering, vapor deposition, CVD, and ALD.

[0190] As the sacrificial film 141, metal 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 metal materials, can be used. In particular, it is preferable to use low-melting-point materials such as aluminum or silver.

[0191] Furthermore, metal oxides such as indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO) can be used as the sacrificial film 141. In addition, indium oxide, indium zinc oxide (In-Zn oxide), indium tin 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.

[0192] Furthermore, the above-mentioned method can also be applied when element M (where M is one or more selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) is used instead of gallium. In particular, it is preferable that M be one or more selected from gallium, aluminum, or yttrium.

[0193] Furthermore, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used as the sacrificial film 141.

[0194] Furthermore, it is preferable to use a material that is soluble in a chemically stable solvent as the sacrificial film 141. In particular, a material that is soluble in water or alcohol can be suitably used for the sacrificial film 141. When forming the sacrificial film 141, it is preferable to apply it using a wet film formation method while 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 layer 112_2A, the interlayer 113A, and layer 112_1A.

[0195] Wet film deposition methods that can be used to form the sacrificial film 141 include 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.

[0196] As the sacrificial film 141, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used.

[0197] Next, a protective film 143 is formed on the sacrificial film 141 (Figure 11A).

[0198] The protective film 143 is used as a mask when etching the sacrificial film 141 later. Furthermore, when the protective film 143 is etched later, the sacrificial film 141 is exposed. Therefore, a combination of films with a high etching selectivity ratio for each other is selected for the sacrificial film 141 and the protective film 143. Thus, the film that can be used for the protective film 143 can be selected according to the etching conditions for both the sacrificial film 141 and the protective film 143.

[0199] For example, when dry etching using a fluorine-containing gas (also called a fluorine-based gas) is used to etch the protective film 143, silicon, silicon nitride, silicon oxide, tungsten, titanium, molybdenum, tantalum, tantalum nitride, an alloy containing molybdenum and niobium, or an alloy containing molybdenum and tungsten can be used for the protective film 143. Here, metal oxide films such as IGZO and ITO can be used for the protective film 143, as they allow for a higher selectivity ratio for etching (i.e., a slower etching rate) compared to dry etching using the above-mentioned fluorine-based gas.

[0200] However, the protective film 143 can be selected from a variety of materials depending on the etching conditions of the sacrificial film 141 and the protective film 143. For example, it can be selected from films that can be used for the sacrificial film 141.

[0201] Furthermore, a nitride film can be used as the protective film 143, for example. Specifically, nitrides such as silicon nitride, aluminum nitride, hafnium nitride, titanium nitride, tantalum nitride, tungsten nitride, gallium nitride, and germanium nitride can be used.

[0202] Alternatively, an oxide film can be used as the protective film 143. Typically, oxide films or oxynitride films such as silicon oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, hafnium oxide, and hafnium oxynitride can be used.

[0203] Next, a resist mask 145 is formed on the protective film 143 (Figure 11B).

[0204] The resist mask 145 can use a resist material containing a photosensitive resin, such as a positive-type resist material or a negative-type resist material.

[0205] If a resist mask 145 is formed on the sacrificial film 141 without forming a protective film 143, and if defects such as pinholes exist in the sacrificial film 141, the solvent in the resist material may dissolve the film that will later become layer 184 on layer 112_2A. Using a protective film 143 can prevent such problems from occurring.

[0206] Furthermore, if a sacrificial film 141 is used that is less prone to defects such as pinholes, the resist mask 145 may be formed directly on the sacrificial film 141 without using the protective film 143.

[0207] Next, the portion of the protective film 143 not covered by the resist mask 145 is removed by etching to form a protective layer 149. At the same time, a protective layer 149 is also formed on the connection portion 140.

[0208] When etching the protective film 143, it is preferable to use etching conditions with a high selectivity ratio so that the sacrificial film 141 is not removed by the etching. The protective film 143 can be etched by wet etching or dry etching, but using dry etching can suppress the reduction of the pattern of the protective film 143.

[0209] Next, remove the resist mask 145 (Figure 11C).

[0210] The resist mask 145 can be removed by wet etching or dry etching. In particular, it is preferable to remove the resist mask 145 by dry etching (also called plasma ashing) using oxygen gas as the etching gas.

[0211] In this case, the removal of the resist mask 145 is performed with the sacrificial film 141 on layer 112_2A, thus suppressing the impact on layer 112_2A, the interlayer 113A, and layer 112_1A. This is particularly suitable when etching using oxygen gas, such as plasma ashing, is performed, as contact with oxygen can adversely affect the electrical properties of layers 112_1A and 112_2A.

[0212] Next, using the protective layer 149 as a mask, the portion of the sacrificial film 141 not covered by the protective layer 149 is removed by etching to form a sacrificial layer 147 (Figure 11D). At the same time, a sacrificial layer 147 is also formed on the connection portion 140.

[0213] The sacrificial film 141 can be etched by wet etching or dry etching, but dry etching is preferred because it can suppress pattern reduction.

[0214] Next, using the sacrificial layer 147 as a mask, the layers 112_2A, the interlayer 113A, the layer 112_1A, and a portion of the conductive film 111A that are not covered by the sacrificial layer 147 are removed by etching to form the light-emitting unit 112_2, the interlayer 113, the light-emitting unit 112_1, the pixel electrode 111, and the connecting electrode 111C (Figure 11E). The protective layer 149 may be removed by etching simultaneously with or before etching the layers 112_2A, the interlayer 113A, the layer 112_1A, and the conductive film 111A.

[0215] For etching layer 112_2A, interlayer 113A, layer 112_1A, and conductive film 111A, it is preferable to use dry etching with an etching gas that does not contain oxygen as its main component. This suppresses deterioration of layer 112_2A, interlayer 113A, layer 112_1A, and conductive film 111A, thereby realizing a highly reliable display device. Examples of etching gases that do not contain oxygen as their main component include noble gases such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, H2, or He. Alternatively, a mixed gas of the above gas and an oxygen-free diluent gas can be used as the etching gas.

[0216] During etching of the conductive film 111A, a portion of the layer 101 containing the transistor (specifically, the insulating layer located on the outermost surface) may be etched, 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.

[0217] Next, an insulating film 121A, which will later become the sidewall 121a, is deposited to cover the pixel electrode 111, the connecting electrode 111C, the light-emitting unit 112_1, the intermediate layer 113, the light-emitting unit 112_2, the sacrificial layer 147, and the protective layer 149. Then, an insulating film 121B, which will later become the sidewall 121b, is deposited on the insulating film 121A (Figure 12A).

[0218] The insulating film 121A is preferably formed using a method that minimizes damage to the light-emitting unit 112. Furthermore, both the insulating film 121A and the insulating film 121B are formed at a temperature lower than the heat resistance temperature of the light-emitting unit 112. For example, an aluminum oxide film can be formed as the insulating film 121A using the ALD method. The ALD method is preferred because it allows for the formation of a film with high coverage. Alternatively, for example, a silicon oxide-nitride film or silicon nitride film can be formed as the insulating film 121B using the PECVD method or the sputtering method.

[0219] Next, the insulating film 121B and the insulating film 121A are etched to form the sidewalls 121b and 121a (Figure 12B). The sidewall 121a is formed to cover at least a portion of the side surface of the pixel electrode 111 and the side surface of the connecting electrode 111C. This prevents the light-emitting element from short-circuiting by contacting the pixel electrode 111 or the connecting electrode 111C with the common layer 114 or common electrode 115 that will be formed later. Furthermore, it is preferable that the sidewall 121a is formed to cover at least a portion of the side surface of the light-emitting unit 112_1, the side surface of the intermediate layer 113, and the side surface of the light-emitting unit 112_2. This prevents the common layer 114 or common electrode 115 that will be formed later from coming into contact with the light-emitting unit 112_1, the intermediate layer 113, and the light-emitting unit 112_2, thereby preventing the light-emitting element from short-circuiting. Furthermore, damage to the light-emitting unit 112_1, the intermediate layer 113, and the light-emitting unit 112_2 in subsequent processes can be suppressed.

[0220] 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 side surface of the pixel electrode 111 and the entire side surface of the connecting electrode 111C with the side wall 121a.

[0221] Here, the side wall 121b is formed to cover at least a portion of the side surface of the side wall 121a.

[0222] The insulating film 121A and insulating film 121B are preferably etched by a dry etching method. The etching of insulating film 121A and insulating film 121B is preferably performed by anisotropic etching. Here, the insulating film 121A and insulating film 121B can be etched using the etching gas that can be used when etching the sacrificial film 141. Furthermore, since the light-emitting unit 112_2 is not exposed when etching insulating film 121A and insulating film 121B, there is a wider range of etching method options than when etching the sacrificial film 141. Specifically, when etching insulating film 121A and insulating film 121B, an etching gas containing oxygen may be used.

[0223] Next, the sacrificial layer 147 and the protective layer 149 are removed (Figure 12C). This exposes the light-emitting unit 112_2 and the connecting electrode 111C.

[0224] Next, a common layer 114 is formed on the side wall 121 and on the light-emitting unit 112_2 (Figure 12D). As a result, a gap 134 may be formed in the region between the side walls 121b and in the recess of the layer 101 containing the transistor. Here, the common layer 114 is not provided on the connecting electrode 111C, and the connecting electrode 111C remains exposed. As mentioned above, the common layer 114 functions as either an electron injection layer or a hole injection layer.

[0225] The common layer 114 can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0226] The common layer 114 is provided so as to cover the upper surface of the light-emitting unit 112_2 and at least a portion of the upper surface and side surface of the side wall 121. If the common layer 114 has high conductivity, there is a risk that the light-emitting element may short-circuit due to contact between the pixel electrode 111 and the common layer 114. However, in a display device according to one aspect of the present invention, since the side wall 121 covers the side surface of the pixel electrode 111, the side surface of the light-emitting unit 112_1, the side surface of the intermediate layer 113, and the side surface of the light-emitting unit 112_2, contact between the highly conductive common layer 114 and these surfaces is suppressed, thereby suppressing a short circuit of the light-emitting element. This improves the reliability of the light-emitting element.

[0227] Next, a common electrode 115 is formed on the common layer 114 and on the connecting electrode 111C (Figure 12E). This forms the light-emitting element 130. For the formation of the common electrode 115, for example, sputtering or vacuum deposition can be used.

[0228] Next, a protective layer 131 is formed on the common electrode 115, and a protective layer 132 is formed on the protective layer 131 (Figure 13A). Methods for forming the protective layers 131 and 132 include vacuum deposition, sputtering, CVD, and ALD. The protective layers 131 and 132 may be formed using different deposition methods. Furthermore, the protective layers 131 and 132 may each be single-layer structures or multi-layer structures.

[0229] Next, colored layers 133a, 133b, and 133c are formed on the protective layer 132, having regions that overlap with the light-emitting units 112_1 and 112_2 (Figure 13B). The colored layers 133a, 133b, and 133c can be formed at desired positions by inkjet or photolithography. Specifically, different colored layers 133 (colored layer 133a, colored layer 133b, or colored layer 133c) can be formed for each light-emitting element 130.

[0230] Subsequently, the display device 100 shown in Figures 3A and 3B can be manufactured by bonding the substrate 120 onto the colored layer 133 using the resin layer 119.

[0231] As described above, in the manufacturing method of the display device of this embodiment, island-shaped light-emitting units having a light-emitting layer are not formed by a pattern on a metal mask, but are formed by etching after the light-emitting unit has been formed on one surface. Therefore, island-shaped light-emitting units can be formed with a uniform thickness. Furthermore, a high-definition display device or a display device with a high aperture ratio can be realized.

[0232] A display device according to one aspect of the present invention has a tandem-structured light-emitting element. The sides of the pixel electrode, light-emitting layer, carrier transport layer, and intermediate layer of the light-emitting element are each covered by a side wall. In the manufacturing process of the display device, the light-emitting unit of the light-emitting element is etched while the light-emitting layer and the carrier transport layer are stacked. As a result, the display device has a configuration in which damage to the light-emitting layer is reduced. Furthermore, the side wall prevents contact between the pixel electrode and the carrier injection layer or common electrode, thereby preventing short circuits in the light-emitting element.

[0233] 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.

[0234] (Embodiment 2) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 14 to 19.

[0235] 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.

[0236] Furthermore, 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.

[0237] [Display Module] Figure 14A shows a perspective view of the display module 280. The display module 280 includes a display device 100 and an FPC 290.

[0238] 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.

[0239] Figure 14B 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.

[0240] The pixel section 284 has a plurality of periodically arranged pixels 110. A magnified view of one pixel 110 is shown on the right side of Figure 14B. Pixel 110 has sub-pixels 110a, 110b, and 110c. Pixel 110 may also have a sub-pixel 110d. The sub-pixels can be arranged in a stripe pattern as shown in Figure 14B. Various sub-pixel arrangement methods, such as a delta pattern or a pentile pattern, can also be applied.

[0241] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0242] A single pixel circuit 283a is a circuit that controls the light emission of the three light-emitting elements of a single pixel 110. A single pixel circuit 283a may be configured to have three circuits that control the light emission of a single light-emitting element. For example, a pixel circuit 283a can be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitor for each light-emitting element. In this case, a gate signal is input to the gate of the selection transistor, and a video signal is input to either the source or the drain. This realizes an active-matrix display device.

[0243] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors with crystalline regions in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0244] 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 preferably has silicon. Examples of silicon include amorphous silicon and crystalline silicon (low-temperature polysilicon, single-crystal silicon, etc.).

[0245] 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.

[0246] 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.

[0247] 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.

[0248] 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 the atomic ratio of In is 4, the atomic ratio of Ga is between 1 and 3, and the atomic ratio of 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 the atomic ratio of In is 5, the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of 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 the atomic ratio of In is 1, the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is greater than 0.1 and 2 or less.

[0249] The transistors in circuit section 282 and the transistors in pixel circuit section 283 may have the same structure or different structures. The structures of the multiple transistors in circuit section 282 may all be the same or there may be two or more different structures. Similarly, the structures of the multiple transistors in pixel circuit section 283 may all be the same or there may be two or more different structures.

[0250] 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.

[0251] The FPC290 functions as wiring for supplying video signals or power potential, etc., to the circuit section 282 from an external source. An IC (integrated circuit) may also be mounted on the FPC290.

[0252] The display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are stacked 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 110 at an extremely high density, enabling an extremely high resolution of the display section 281. For example, it is preferable that the pixels 110 in the display section 281 be 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 a resolution of 20000 ppi or less, or 30000 ppi or less.

[0253] 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.

[0254] [Display device 100A] Figure 15 is a cross-sectional view showing an example of the configuration of the display device 100A. The display device 100A shown in Figure 15 has a transistor 201, a transistor 205, a light-emitting element 130, a colored layer 133a, a colored layer 133b, and a colored layer 133c between a substrate 451 and a substrate 120.

[0255] The light-emitting element 130 can be the light-emitting element exemplified in Embodiment 1.

[0256] Both transistors 201 and 205 are formed on the substrate 451. These transistors can be manufactured using the same materials and processes.

[0257] On the substrate 451, 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.

[0258] 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.

[0259] 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.

[0260] 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.

[0261] An organic insulating film is preferred for the insulating layer 214, which functions as a planarizing layer. Examples of materials that can be used as the organic insulating film include acrylic resins, polyimide resins, epoxy resins, polyamide resins, polyimidoamide resins, siloxane resins, benzocyclobutene resins, phenolic resins, and precursors of these resins.

[0262] In the region 228 shown in Figure 15, an opening is formed in the insulating layer 214. This prevents impurities from entering the light-emitting element 130 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.

[0263] 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.

[0264] 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.

[0265] 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.

[0266] The crystallinity of the semiconductor material used for the transistor is not particularly limited, and any of amorphous semiconductors, single-crystalline semiconductors, or semiconductors having crystallinity other than single crystals (microcrystalline semiconductors, polycrystalline semiconductors, or semiconductors having a crystal region in part) may be used. Using a single-crystalline semiconductor or a semiconductor having crystallinity is preferable because deterioration of transistor characteristics can be suppressed.

[0267] The semiconductor layer of the transistor preferably has a metal oxide. That is, the display device of the present embodiment preferably uses a transistor using a metal oxide for the channel formation region. Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon, crystalline silicon (such as low-temperature polysilicon, single-crystalline silicon, etc.).

[0268] The semiconductor layer preferably has, for example, indium, M (M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin.

[0269] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) as the semiconductor layer.

[0270] When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably not less than the atomic ratio of M. Examples of the atomic ratios of the metal elements in such an In-M-Zn oxide include a composition of In:M:Zn = 1:1:1 or in the vicinity thereof, a composition of In:M:Zn = 1:1:1.2 or in the vicinity thereof, a composition of In:M:Zn = 2:1:3 or in the vicinity thereof, a composition of In:M:Zn = 3:1:2 or in the vicinity thereof, a composition of In:M:Zn = 4:2:3 or in the vicinity thereof, a composition of In:M:Zn = 4:2:4.1 or in the vicinity thereof, a composition of In:M:Zn = 5:1:3 or in the vicinity thereof, a composition of In:M:Zn = 5:1:6 or in the vicinity thereof, a composition of In:M:Zn = 5:1:7 or in the vicinity thereof, a composition of In:M:Zn = 5:1:8 or in the vicinity thereof, a composition of In:M:Zn = 6:1:6 or in the vicinity thereof, a composition of In:M:Zn = 5:2:5 or in the vicinity thereof, and the like. The composition in the vicinity means a range including ±30% of the desired atomic ratio.

[0271] For example, when the atomic ratio is described as In:Ga:Zn = 4:2:3 or in the vicinity thereof, when the atomic ratio of In is 4, it includes cases where the atomic ratio of Ga is not less than 1 and not more than 3, and the atomic ratio of Zn is not less than 2 and not more than 4. Also, when the atomic ratio is described as In:Ga:Zn = 5:1:6 or in the vicinity thereof, when the atomic ratio of In is 5, it includes cases where the atomic ratio of Ga is greater than 0.1 and not more than 2, and the atomic ratio of Zn is not less than 5 and not more than 7. Also, when the atomic ratio is described as In:Ga:Zn = 1:1:1 or in the vicinity thereof, when the atomic ratio of In is 1, it includes cases where the atomic ratio of Ga is greater than 0.1 and not more than 2, and the atomic ratio of Zn is greater than 0.1 and not more than 2.

[0272] A connection portion 204 is provided in a region of the substrate 451 where the substrate 120 does not overlap. In the connection portion 204, a wiring 465 is electrically connected to an FPC 472 via a conductive layer 466 and a connection layer 242. The conductive layer 466 can be formed in the same process as the pixel electrode. On the upper surface of the connection portion 204, the conductive layer 466 is exposed. Thereby, the connection portion 204 and the FPC 472 can be electrically connected via the connection layer 242.

[0273] Various optical components can 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-gathering films. In addition, 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 be placed on the outside of the substrate 120.

[0274] By providing a protective layer 131 that covers the light-emitting element, it is possible to suppress the ingress of impurities such as water into the light-emitting element and improve the reliability of the light-emitting element.

[0275] 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 are in contact with each other through an opening in the insulating layer 214. In particular, it is preferable that the inorganic insulating film of the insulating layer 215 and the inorganic insulating film of the protective layer 131 are in contact with each other. This makes it possible to suppress impurities from entering the light-emitting element 130 from the outside through the organic insulating film. Therefore, the reliability of the display device 100A can be improved.

[0276] Substrates 451 and 120 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 element should be made of a material that transmits the light. Using flexible materials for substrates 451 and 120 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used as substrate 451 or substrate 120.

[0277] As substrates 451 and 120, the following can be used: 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 451 and 120 may be made of glass of a thickness sufficient to provide flexibility.

[0278] Various types of curing adhesives can be used as the adhesive layer, including 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.

[0279] As the connecting layer 242, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), etc., can be used.

[0280] In the display device 100A, a colored layer 133a, a colored layer 133b, and a colored layer 133c are provided between the light-emitting element 130 and the substrate 120. As described above, the transistor is formed on the substrate 451. Therefore, the display device 100A can be a top-emission type display device. Thus, in the display device 100A, the substrate 451 can be a substrate that does not transmit light.

[0281] [Display device 100B] Figure 16 is a cross-sectional view showing an example configuration of the display device 100B. The display device 100B is a modified version of the display device 100A, and differs from the display device 100A in that the colored layers 133a, 133b, and 133c are provided between the light-emitting element 130 and the substrate 451. In other words, the display device 100B can be a bottom-emission type display device. Therefore, in the display device 100B, the substrate 120 can be a substrate that does not have light transmission.

[0282] [Display device 100C] The display device 100C shown in Figure 17 has a substrate 301, a light-emitting element 130, a capacitor 240, and a transistor 310.

[0283] Substrate 301 corresponds to substrate 291 in Figures 14A and 14B. The laminated structure from substrate 301 to insulating layer 255 corresponds to layer 101 containing the transistor in Embodiment 1.

[0284] 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 a source or drain. The insulating layer 314 is provided covering the side surface of the conductive layer 311.

[0285] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0286] Furthermore, an insulating layer 261 is provided covering the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0287] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 positioned therebetween. 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.

[0288] 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 one of the source or drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping the conductive layer 241 via the insulating layer 243.

[0289] An insulating layer 255 is provided to cover the capacitor 240, and a light-emitting element 130 or the like is provided on the insulating layer 255. Further, a protective layer 131 is provided on each of the light-emitting elements 130. A protective layer 132 is provided on the protective layer 131, and a substrate 120 is bonded to the protective layer 132 by a resin layer 119. Details of the components from the light-emitting element to the substrate 120 can be referred to in Embodiment 1. The substrate 120 corresponds to the substrate 292 in FIG. 14A.

[0290] The pixel electrode of the light-emitting element is electrically connected to one of the source or drain of the transistor 310 by the insulating layer 255, a plug 256 embedded in the insulating layer 243, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261.

[0291] [Display device 100D] The display device 100D shown in FIG. 18 mainly differs from the display device 100C in that the configuration of the transistor is different. Note that the description of the same parts as those of the display device 100C may be omitted.

[0292] The transistor 320 is a transistor (OS transistor) in which a metal oxide is applied to a semiconductor layer in which a channel is formed.

[0293] 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.

[0294] Substrate 331 corresponds to substrate 291 in Figures 14A and 14B. The laminated structure from substrate 331 to insulating layer 255 corresponds to layer 101 containing the transistor in Embodiment 1. An insulating substrate or a semiconductor substrate can be used as substrate 331.

[0295] 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.

[0296] 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.

[0297] The semiconductor layer 321 is provided on the insulating layer 326. Preferably, the semiconductor layer 321 has a metal oxide film having semiconductor properties.

[0298] A pair of conductive layers 325 are provided in contact with the semiconductor layer 321 and function as source and drain electrodes.

[0299] 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.

[0300] 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.

[0301] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are flattened so that their heights are approximately the same, and the insulating layer 329 and insulating layer 265 are provided covering them.

[0302] 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.

[0303] 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, 264, and 328. Here, it is preferable that the plug 274 has a conductive layer 274a that covers the sides of the openings of each 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.

[0304] In addition, layer 101 containing the transistor may have various inorganic insulating films. Examples of inorganic insulating films 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 be used. Furthermore, two or more of the above insulating films may be stacked and used.

[0305] 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.

[0306] [Display device 100E] The display device 100E shown in Figure 19 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.

[0307] 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.

[0308] 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.

[0309] This configuration allows for the formation of not only pixel circuits but also drive circuits and other components directly beneath the light-emitting element, making it possible to miniaturize the display device compared to cases where the drive circuits are located around the display area.

[0310] This embodiment can be combined with other embodiments as appropriate.

[0311] (Embodiment 3) This embodiment describes metal oxides that can be used in the OS transistor described in the above embodiment.

[0312] 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.

[0313] Furthermore, metal oxides can be formed by methods such as sputtering, CVD (Chemical Vapor Deposition) methods including MOCVD, or ALD (Artificial Alkaline Dissolution).

[0314] <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.

[0315] 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.

[0316] 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.

[0317] 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.

[0318] <<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.

[0319] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0320] [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.

[0321] 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.

[0322] 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.

[0323] 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.

[0324] 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.

[0325] 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.

[0326] 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.

[0327] 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.

[0328] [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.

[0329] [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.

[0330] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0331] [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.

[0332] 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.

[0333] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS of In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of the CAC-OS film. The second region is the region where [Ga] is greater than the [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is the region where [In] is greater than the [In] in the second region, and [Ga] is smaller than the [Ga] in the second region. The second region is the region where [Ga] is greater than the [Ga] in the first region, and [In] is smaller than the [In] in the first region.

[0334] 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.

[0335] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

[0336] 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.

[0337] 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.

[0338] 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.

[0339] 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.

[0340] 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.

[0341] 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.

[0342] Furthermore, transistors using CAC-OS offer high reliability. Therefore, CAC-OS is ideal for various semiconductor devices, including display devices.

[0343] 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.

[0344] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0345] 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.

[0346] For the transistor, it is preferable to use an oxide semiconductor with a low carrier concentration. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 or less, preferably 1×10 15 cm -3 or less, more preferably 1×10 13 cm -3 or less, still more preferably 1×10 11 cm -3 or less, yet more preferably 1×10 10 cm -3 or less, and 1×10 -9 cm -3 or more. When reducing the carrier concentration of the oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced and the density of defect levels may be reduced. In this specification and the like, a low impurity concentration and a low density of defect levels are referred to as high purity intrinsic or substantially high purity intrinsic. In some cases, an oxide semiconductor with a low carrier concentration is referred to as a high purity intrinsic or substantially high purity intrinsic oxide semiconductor.

[0347] In addition, since an oxide semiconductor film with high purity intrinsic or substantially high purity intrinsic has a low density of defect levels, the density of trap levels may also be low.

[0348] In addition, the charges trapped in the trap levels of the oxide semiconductor may take a long time to disappear and may behave like fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap levels may have unstable electrical characteristics.

[0349] Therefore, in order to stabilize the electrical characteristics of the transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. In addition, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in the adjacent film. Impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, and the like.

[0350] <Impurity> Here, we will explain the effects of various impurities in oxide semiconductors.

[0351] 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:

[0352] 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:

[0353] 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 / cm3 More preferably 5 × 10 17 atoms / cm 3 Do the following:

[0354] 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.

[0355] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be provided.

[0356] This embodiment can be combined with other embodiments as appropriate.

[0357] (Embodiment 4) In this embodiment, an electronic device according to one aspect of the present invention will be described with reference to Figures 20 to 24.

[0358] 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.

[0359] 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.

[0360] 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.

[0361] 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.

[0362] 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).

[0363] 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.

[0364] Figures 20A, 20B, 21A, and 21B illustrate an example of a wearable device that can be worn on the head. These wearable devices have the function of displaying AR content, or the function of displaying VR content, or both. 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.

[0365] The electronic device 700A shown in Figure 20A and the electronic device 700B shown in Figure 20B 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.

[0366] 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.

[0367] 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 756 superimposed on the transmitted image visible through the optical element 753. Therefore, electronic devices 700A and 700B are electronic devices capable of AR display.

[0368] 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.

[0369] 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.

[0370] Furthermore, electronic devices 700A and 700B are equipped with batteries that can be charged wirelessly, wired, or both.

[0371] 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.

[0372] 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.

[0373] 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.

[0374] The electronic device 800A shown in Figure 21A and the electronic device 800B shown in Figure 21B 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.

[0375] 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.

[0376] 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.

[0377] 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.

[0378] 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.

[0379] The attachment portion 823 allows the user to attach the electronic device 800A or 800B to their head. While Figure 21A 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.

[0380] 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.

[0381] 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.

[0382] 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.

[0383] 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.

[0384] 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 20A 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 21A has a function for transmitting information to the earphone 750 through its wireless communication function.

[0385] Furthermore, the electronic device may have an earphone section. The electronic device 700B shown in Figure 20B 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.

[0386] Similarly, the electronic device 800B shown in Figure 21B 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.

[0387] 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.

[0388] 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.

[0389] Furthermore, an electronic device according to one aspect of the present invention can transmit information to earphones via wired or wireless means.

[0390] The electronic device 6500 shown in Figure 22A is a portable information terminal that can be used as a smartphone.

[0391] 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.

[0392] A display device according to one aspect of the present invention can be applied to the display unit 6502.

[0393] Figure 22B is a schematic cross-sectional view of the housing 6501, including the end on the microphone 6506 side.

[0394] 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.

[0395] 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).

[0396] 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.

[0397] 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.

[0398] Figure 23A 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.

[0399] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0400] The television device 7100 shown in Figure 23A 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.

[0401] 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.

[0402] Figure 23B 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.

[0403] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0404] Figures 23C and 23D show examples of digital signage.

[0405] The digital signage 7300 shown in Figure 23C comprises 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.

[0406] Figure 23D 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.

[0407] In Figures 23C and 23D, a display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0408] 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.

[0409] 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.

[0410] Furthermore, as shown in Figures 23C and 23D, 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.

[0411] 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.

[0412] The electronic equipment shown in Figures 24A to 24F 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.

[0413] The electronic devices shown in Figures 24A to 24F 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.

[0414] Details of the electronic equipment shown in Figures 24A to 24F will be explained below.

[0415] Figure 24A 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 24A 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.

[0416] Figure 24B 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.

[0417] Figure 24C 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.

[0418] Figures 24D to 24F are perspective views showing a foldable personal information terminal 9201. Figure 24D shows the personal information terminal 9201 in an unfolded state, Figure 24F shows it in a folded state, and Figure 24E shows a perspective view of the state in between, transitioning from one of Figures 24D or 24F to the other. The personal 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 personal 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.

[0419] This embodiment can be combined with other embodiments as appropriate. [Explanation of Symbols]

[0420] 100: Display device, 100A: Display device, 100B: Display device, 100C: Display device, 100D: Display device, 100E: Display device, 101: Layer, 103a: Layer, 103b: Layer, 110: Pixel, 110a: Sub-pixel, 110b: Sub-pixel, 110c: Sub-pixel, 110d: Sub-pixel, 111: Pixel electrode, 111A: Conductive film, 111C: Connecting electrode, 112: Light-emitting unit, 112_1: Light-emitting unit, 112_1A: Layer, 112_2: Light-emitting unit, 112_2A: Layer, 112_3: Light-emitting unit, 113: Intermediate layer, 113_1: Intermediate layer, 113_2: Intermediate layer, 113 A: Interlayer, 114: Common layer, 114a: Layer, 115: Common electrode, 119: Resin layer, 120: Substrate, 121: Sidewall, 121a: Sidewall, 121A: Insulating film, 121b: Sidewall, 121B: Insulating film, 125a: Pixel, 125b: Pixel, 130: Light-emitting element, 131: Protective layer, 132: Protective layer, 133: Colored layer, 133a: Colored layer, 133b: Colored layer, 133c: Colored layer, 134: Void, 140: Connection part, 141: Sacrificial film, 143: Protective film, 145: Resist mask, 147: Sacrificial layer, 149: Protective layer, 181: Layer, 182: Layer, 183: Light-emitting layer, 183_1: Light-emitting layer ,183_2: Light-emitting layer, 183_3: Light-emitting layer, 184: Layer, 201: Transistor, 204: Connection part, 205: Transistor, 211: Insulating layer, 213: Insulating layer, 214: Insulating layer, 215: Insulating layer, 221: Conductive layer, 222a: Conductive layer, 222b: Conductive layer, 223: Conductive layer, 228: 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, 255: Insulating layer, 256: Plug, 261: Insulating layer, 262: Insulating layer, 263: Insulating layer, 264: Insulating layer, 265: Insulating layer, 271: Plug, 274: Plug, 274a: Conductive layer, 274b: Conductive layer, 280: Display module, 281: Display section, 282: Circuit section, 283: Pixel circuit section, 283a: Pixel circuit, 284: Pixel section, 285: Terminal section, 286: Wiring section, 290: FPC, 291: Substrate, 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, 451: Substrate, 465: Wiring, 466: Conductive layer, 472: FPC, 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 part 821: Housing, 822: Communication unit, 823: 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, 65 16: IC, 6517: Printed circuit board, 6518: Battery, 7000: Display unit, 7100: Television equipment, 7101: Enclosure, 7103: Stand, 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, 74 00: Digital signage, 7401: Pillar, 7411: Information terminal, 9000: Enclosure, 9001: Display unit, 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: Portable information terminal, 9102: Portable information terminal, 9200: Portable information terminal, 9201: Portable information terminal,

Claims

1. It has a first light-emitting element, a second light-emitting element, a first side wall, a second side wall, a third side wall, and a fourth side wall. The first light-emitting element comprises a first pixel electrode, a first light-emitting layer on the first pixel electrode, a first intermediate layer on the first light-emitting layer, a second light-emitting layer on the first intermediate layer, and a common electrode on the second light-emitting layer. The second light-emitting element comprises a second pixel electrode, a third light-emitting layer on the second pixel electrode, a second intermediate layer on the third light-emitting layer, a fourth light-emitting layer on the second intermediate layer, and the common electrode on the fourth light-emitting layer. The first light-emitting element and the second light-emitting element are adjacent to each other. The first sidewall covers at least a portion of the side surface of the first pixel electrode, the side surfaces of the first and second light-emitting layers, and the side surface of the first intermediate layer. The second side wall covers at least a portion of the side surface of the first side wall. The third sidewall covers at least a portion of the side surface of the second pixel electrode, the side surfaces of the third and fourth light-emitting layers, and the side surface of the second intermediate layer. The fourth side wall covers at least a portion of the side surface of the third side wall. A display device having a gap between the second side wall and the fourth side wall.

2. In claim 1, The second side wall covers at least a portion of the upper surface of the first side wall. The fourth side wall is a display device that covers at least a portion of the upper surface of the third side wall.

3. In claim 1 or claim 2, The common electrode has a protective layer, The protective layer has a first colored layer such that it overlaps with the first light-emitting layer and the second light-emitting layer. The protective layer has a second colored layer such that it overlaps with the third and fourth light-emitting layers. The first colored layer and the second colored layer have the function of transmitting light of different colors. The first light-emitting layer and the third light-emitting layer have the function of emitting light of the same color. A display device having the function of emitting light of the same color, wherein the second light-emitting layer and the fourth light-emitting layer.

4. In any one of claims 1 to 3, A common layer is provided between the second and fourth light-emitting layers and the common electrode. The common layer functions as either an electron injection layer or a hole injection layer in the first and second light-emitting elements of the display device.

5. In any one of claims 1 to 4, The first pixel electrode and the second pixel electrode are provided on an insulating layer. The insulating layer has a first protrusion in the region overlapping with the first pixel electrode, The insulating layer is a display device having a second protrusion in a region that overlaps with the second pixel electrode.

6. A display device according to any one of claims 1 to 5, A display module having at least one of a connector and an integrated circuit.

7. The display module according to claim 6, An electronic device comprising at least one of a housing, a battery, a camera, a speaker, and a microphone.

8. Form an insulating layer, A conductive film, a first light-emitting film, an interlayer, a second light-emitting film, and a sacrificial film are sequentially formed on the insulating layer. The sacrificial film, the second light-emitting film, the interlayer, the first light-emitting film, and the conductive film are etched to form a first pixel electrode and a second pixel electrode on the insulating layer, a first light-emitting layer on the first pixel electrode and a second light-emitting layer on the second pixel electrode, a first interlayer on the first light-emitting layer and a second interlayer on the second light-emitting layer, a third light-emitting layer on the first interlayer and a fourth light-emitting layer on the second interlayer, a first sacrificial layer on the third light-emitting layer and a second sacrificial layer on the fourth light-emitting layer, An insulating film is formed to cover at least a portion of the side surfaces of the first and second pixel electrodes, the side surfaces of the first to fourth light-emitting layers, the side surfaces of the first and second intermediate layers, and the side surfaces and top surfaces of the first and second sacrificial layers. The insulating film is etched to form a first sidewall covering at least a portion of the side surface of the first pixel electrode, and a second sidewall covering at least a portion of the side surface of the second pixel electrode. Remove the first sacrificial layer and the second sacrificial layer, A method for manufacturing a display device in which a common electrode is formed on the third light-emitting layer and the fourth light-emitting layer.

9. Form an insulating layer, A conductive film, a first light-emitting film, an interlayer, a second light-emitting film, and a sacrificial film are sequentially formed on the insulating layer. The sacrificial film, the second light-emitting film, the interlayer, the first light-emitting film, and the conductive film are etched to form a first pixel electrode and a second pixel electrode on the insulating layer, a first light-emitting layer on the first pixel electrode and a second light-emitting layer on the second pixel electrode, a first interlayer on the first light-emitting layer and a second interlayer on the second light-emitting layer, a third light-emitting layer on the first interlayer and a fourth light-emitting layer on the second interlayer, a first sacrificial layer on the third light-emitting layer and a second sacrificial layer on the fourth light-emitting layer, A first insulating film is formed to cover at least a portion of the side surfaces of the first and second pixel electrodes, the side surfaces of the first to fourth light-emitting layers, the side surfaces of the first and second intermediate layers, and the side surfaces and top surfaces of the first and second sacrificial layers. A second insulating film is formed on the first insulating film. The first insulating film and the second insulating film are etched to form a first sidewall covering at least a portion of the side surface of the first pixel electrode, a second sidewall covering at least a portion of the side surface of the second pixel electrode, a third sidewall covering at least a portion of the side surface of the first sidewall, and a fourth sidewall covering at least a portion of the side surface of the second sidewall. Remove the first sacrificial layer and the second sacrificial layer, A method for manufacturing a display device in which a common electrode is formed on the third light-emitting layer and the fourth light-emitting layer.

10. In claim 8 or 9, A method for manufacturing a display device, comprising etching the conductive film using the first sacrificial layer and the second sacrificial layer as masks.

11. In any one of claims 8 to 10, A protective layer is formed on the common electrode. A first colored layer having regions that overlap with the first and third light-emitting layers, and a second colored layer having regions that overlap with the second and fourth light-emitting layers are formed on the protective layer. A method for manufacturing a display device having a first colored layer and a second colored layer that transmit light of different colors.

12. In any one of claims 8 to 11, After removing the first sacrificial layer and the second sacrificial layer, a common layer having the function of either an electron injection layer or a hole injection layer is formed on the third light-emitting layer and the fourth light-emitting layer. A method for manufacturing a display device in which the common electrode is formed on the common layer.

13. In any one of claims 8 to 12, A method for manufacturing a display device in which a recess is formed in the insulating layer during the etching process of the conductive film.

Images