Display device

Abstract

To provide a display device with high definition or high resolution.SOLUTION: A conductive film, a first layer, and a first sacrifice layer are formed. A part of the conductive film is exposed by processing the first layer and the first sacrifice layer. On the first sacrifice layer and the conductive film, a second layer and a second sacrifice layer are formed. By processing the second layer and the second sacrifice layer, a part of the conductive film is exposed. By processing the conductive film, a first pixel electrode overlapping with the first sacrifice layer and a second pixel electrode overlapping with the second sacrifice layer are formed. An insulating film that covers at least a side surface of each of the first pixel electrode, the second pixel electrode, the first layer, and the second layer, a side surface and an upper surface of the first sacrifice layer, and a side surface and an upper surface of the second sacrifice layer is formed. By processing the insulating film, a side wall that covers at least the side surface of each of the first pixel electrode, the second pixel electrode, the first layer, and the second layer is formed. By removing the first sacrifice layer and the second sacrifice layer, a common electrode is formed on the first layer and the second layer. Thus, a display device is manufactured.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] BACKGROUND OF THE INVENTION 1. Field of the Invention One embodiment of the present invention relates to a method for manufacturing a display device, a display module, and an electronic device.

[0002] One embodiment of the present invention is not limited to the above technical field, and examples of the technical field of one embodiment of the present invention include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), driving methods thereof, and manufacturing methods thereof. [Background technology]

[0003] In recent years, display devices are expected to be used in a variety of applications. For example, applications of large display devices include home television devices (also called televisions or television receivers), digital signage, and public information displays (PIDs). In addition, development of mobile information terminals such as smartphones and tablet terminals equipped with touch panels is progressing.

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

[0005] As a display device, for example, a light-emitting device having a light-emitting device (also called a light-emitting element) has been developed. A light-emitting device (also called an EL device or an EL element) utilizing the electroluminescence (hereinafter referred to as EL) phenomenon has features such as being easily thin and lightweight, being capable of high-speed response to input signals, and being capable of being driven by a DC constant voltage power supply, and is therefore applied to a display device.

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

[0007] [Patent Document 1] International Publication No. 2018 / 087625 Summary of the Invention [Problem to be solved by the invention]

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

[0009] For example, island-shaped light-emitting layers can be formed by vacuum deposition using a metal mask (also called a shadow mask). However, during deposition, the contours of the layer can become blurred, resulting in thin edges. This means that the thickness of the island-shaped light-emitting layer can vary depending on the location. Furthermore, when producing large, high-resolution, or high-definition displays, there is a concern that the manufacturing yield will be low due to the low dimensional accuracy of the metal mask and deformation due to heat, etc.

[0010] Furthermore, when manufacturing display devices using a vacuum deposition method that uses a metal mask, there is a problem that multiple lines of manufacturing equipment are required. For example, because the metal mask needs to be cleaned periodically, at least two or more lines of manufacturing equipment must be prepared, and one manufacturing equipment must be used for manufacturing while the other manufacturing equipment is under maintenance. Considering mass production, multiple lines of manufacturing equipment are required. Therefore, there is a problem that the initial investment for introducing the manufacturing equipment is very large.

[0011] An object of one embodiment of the present invention is to provide a method for manufacturing a high-resolution display device.An object of one embodiment of the present invention is to provide a method for manufacturing a high-resolution display device.An object of one embodiment of the present invention is to provide a method for manufacturing a large-sized display device.An object of one embodiment of the present invention is to provide a method for manufacturing a highly reliable display device.An object of one embodiment of the present invention is to provide a method for manufacturing a display device with a high yield.

[0012] An object of one embodiment of the present invention is to provide a high-resolution display device.An object of one embodiment of the present invention is to provide a high-resolution display device.An object of one embodiment of the present invention is to provide a large-sized display device.An object of one embodiment of the present invention is to provide a highly reliable display device.

[0013] Note that the description of these problems does not preclude the existence of other problems. One embodiment of the present invention does not necessarily have to solve all of these problems. Problems other than these can be extracted from the description in the specification, drawings, and claims. [Means for solving the problem]

[0014] One embodiment of the present invention is to form an insulating layer, form a conductive film over the insulating layer, form a first layer over the conductive film, form a first sacrificial layer over the first layer, process the first layer and the first sacrificial layer to expose a part of the conductive film, form a second layer over the first sacrificial layer and the conductive film, form a second sacrificial layer over the second layer, process the second layer and the second sacrificial layer to expose a part of the conductive film, and process the conductive film, thereby forming a first pixel electrode overlapping with the first sacrificial layer and a second pixel electrode overlapping with the second sacrificial layer. a first insulating film that covers at least the side surfaces of the first pixel electrode, the side surfaces of the second pixel electrode, the side surfaces of the first layer, the side surfaces of the second layer, the side surfaces and top surface of the first sacrificial layer, and the side surfaces and top surface of the second sacrificial layer; processing the insulating film to form side walls that cover at least the side surfaces of the first pixel electrode, the side surfaces of the second pixel electrode, the side surfaces of the first layer, and the side surfaces of the second layer; removing the first sacrificial layer and the second sacrificial layer; and forming a common electrode on the first layer and the second layer.

[0015] Alternatively, one embodiment of the present invention includes forming an insulating layer, forming a conductive film over the insulating layer, forming a first layer over the conductive film, forming a first sacrificial layer over the first layer, processing the first layer and the first sacrificial layer to expose a part of the conductive film, forming a second layer over the first sacrificial layer and the conductive film, forming the second sacrificial layer over the second layer, processing the second layer and the second sacrificial layer to expose a part of the conductive film, forming a first insulating film that covers at least side surfaces of the first layer, side surfaces of the second layer, side surfaces and a top surface of the first sacrificial layer, and side surfaces and a top surface of the second sacrificial layer, and processing the first insulating film to cover the side surfaces of the first layer and the second layer. a first sidewall is formed, and a conductive film is processed to form a first pixel electrode overlapping with the first sacrificial layer and the first sidewall, and a second pixel electrode overlapping with the second sacrificial layer and the first sidewall; a second insulating film is formed to cover at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, a side surface of the first sidewall, an upper surface of the first sacrificial layer, and an upper surface of the second sacrificial layer; the second insulating film is processed to form a second sidewall to cover at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, and a side surface of the first sidewall; the first sacrificial layer and the second sacrificial layer are removed; and a common electrode is formed on the first layer and the second layer.

[0016] It is preferable to process the conductive film using the first sacrificial layer and the second sacrificial layer as a hard mask. Alternatively, it is preferable to form a first resist mask on the first sacrificial layer, process the first layer and the first sacrificial layer using the first resist mask, form a second resist mask on the second sacrificial layer, process the second layer and the second sacrificial layer using the second resist mask, and process the conductive film using the first resist mask and the second resist mask.

[0017] It is preferable to form a protective layer on the common electrode.

[0018] After removing the first sacrificial layer and the second sacrificial layer, it is preferable to form a third layer on the first layer and the second layer, and to form a common electrode on the third layer.

[0019] In the process of processing the conductive film, it is preferable to form a recess in the insulating layer.

[0020] One embodiment of the present invention is a display device having a first light-emitting device, a second light-emitting device, and a first sidewall. The first light-emitting device has a first pixel electrode, a first light-emitting layer on the first pixel electrode, and a common electrode on the first light-emitting layer. The second light-emitting device has a second pixel electrode, a second light-emitting layer on the second pixel electrode, and a common electrode on the second light-emitting layer. The first light-emitting device and the second light-emitting device have a function of emitting light of different colors. The first sidewall covers at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, a side surface of the first light-emitting layer, and a side surface of the second light-emitting layer.

[0021] The first light-emitting device preferably has a first hole injection layer on the first pixel electrode, a first hole transport layer on the first hole injection layer, and a first electron transport layer on the first light-emitting layer, each of which has a side surface covered by the first sidewall, and further has an electron injection layer on the first electron transport layer.The second light-emitting device preferably has a second hole injection layer on the second pixel electrode, a second hole transport layer on the second hole injection layer, and a second electron transport layer on the second light-emitting layer, each of which has a side surface covered by the first sidewall, and further has an electron injection layer on the second electron transport layer.

[0022] Alternatively, the first light-emitting device preferably has a first hole injection layer on the first pixel electrode, a first hole transport layer on the first hole injection layer, a first electron transport layer on the first light-emitting layer, and a first electron injection layer on the first electron transport layer, each of which has a side surface covered by the first sidewall.The second light-emitting device preferably has a second hole injection layer on the second pixel electrode, a second hole transport layer on the second hole injection layer, a second electron transport layer on the second light-emitting layer, and a second electron injection layer on the second electron transport layer, each of which has a side surface covered by the first sidewall.

[0023] Alternatively, the first light-emitting device preferably has a first light-emitting unit on a first pixel electrode, a first intermediate layer on the first light-emitting unit, and a second light-emitting unit on the first intermediate layer, each of which has a side surface covered by a first sidewall. The second light-emitting device preferably has a third light-emitting unit on a second pixel electrode, a second intermediate layer on the third light-emitting unit, and a fourth light-emitting unit on the second intermediate layer, each of which has a side surface covered by a first sidewall. The first light-emitting unit and the second light-emitting unit preferably each emit light of a first color. The third light-emitting unit and the fourth light-emitting unit preferably each emit light of a second color.

[0024] It is preferable that the light-emitting element further has a second sidewall. The second sidewall preferably covers at least the side surfaces of the first light-emitting layer and the second light-emitting layer. The first sidewall preferably covers at least a part of the side surface of the second sidewall.

[0025] It is preferable to have a protective layer on the common electrode.

[0026] The first light emitting device and the second light emitting device are preferably provided on an insulating layer, which preferably has a recess.

[0027] It is preferable to have an air gap between the first light emitting device and the second light emitting device.

[0028] One aspect of the present invention is a display module having a display device having any of the above configurations, and including a connector such as a flexible printed circuit (hereinafter referred to as FPC) or a TCP (Tape Carrier Package), or a display module having an integrated circuit (IC) mounted thereon by a COG (Chip On Glass) method or a COF (Chip On Film) method.

[0029] One embodiment of the present invention is an electronic device including the above-described display module and at least one of a housing, a battery, a camera, a speaker, and a microphone. [Effects of the Invention]

[0030] According to one embodiment of the present invention, a method for manufacturing a high-resolution display device can be provided. According to one embodiment of the present invention, a method for manufacturing a high-resolution display device can be provided. According to one embodiment of the present invention, a method for manufacturing a large-sized display device can be provided. According to one embodiment of the present invention, a method for manufacturing a highly reliable display device can be provided. According to one embodiment of the present invention, a method for manufacturing a display device with high yield can be provided.

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

[0032] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims. [Brief explanation of the drawings]

[0033] [Figure 1] 1A and 1B are a top view and a cross-sectional view, respectively, illustrating an example of a display device. [Figure 2] 2A to 2C are top views showing an example of a display device. [Figure 3] 3A to 3C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 4] 4A to 4C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 5] 5A to 5C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 6]6A to 6C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 7] 7A to 7C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 8] 8A to 8C are cross-sectional views showing an example of a display device. [Figure 9] 9A and 9C are cross-sectional views showing an example of a display device. [Figure 10] 10A to 10C are cross-sectional views showing an example of a display device. [Figure 11] 11A to 11C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 12] 12A to 12C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 13] 13A to 13C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 14] 14A and 14B are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 15] 15A and 15B are cross-sectional views showing an example of a display device. [Figure 16] 16A and 16B are cross-sectional views showing an example of a display device. [Figure 17] 17A and 17B are cross-sectional views showing an example of a display device. [Figure 18] 18A to 18C are cross-sectional views showing an example of a display device. [Figure 19] 19A and 19B are perspective views showing an example of a display module. [Figure 20] FIG. 20 is a cross-sectional view showing an example of a display device. [Figure 21] FIG. 21 is a cross-sectional view showing an example of a display device. [Figure 22] FIG. 22 is a cross-sectional view showing an example of a display device. [Figure 23] 23A to 23D are diagrams showing configuration examples of a light-emitting device. [Figure 24]24A and 24B are diagrams showing an example of an electronic device. [Figure 25] 25A and 25B are diagrams showing an example of an electronic device. [Figure 26] 26A and 26B are diagrams showing an example of an electronic device. [Figure 27] 27A to 27D are diagrams showing an example of an electronic device. [Figure 28] 28A to 28F are diagrams showing an example of an electronic device. DETAILED DESCRIPTION OF THE INVENTION

[0034] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various changes can be made in form and detail without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0035] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted. In addition, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be assigned.

[0036] Furthermore, for ease of understanding, the position, size, range, etc. of each component shown in the drawings may not represent the actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings.

[0037] It should be noted that the terms "film" and "layer" can be interchangeable depending on the circumstances. For example, the term "conductive layer" can be changed to the term "conductive film." Or, for example, the term "insulating film" can be changed to the term "insulating layer."

[0038] (Embodiment 1) In this embodiment, a display device of one embodiment of the present invention and a manufacturing method thereof will be described with reference to FIGS.

[0039] In a manufacturing method of a display device according to one embodiment of the present invention, a conductive film is formed, and a first layer (which can be referred to as an EL layer or a part of an EL layer) including a light-emitting layer emitting light of a first color is formed over the entire surface. Then, a first sacrificial layer is formed over the first layer. Then, a first resist mask is formed over the first sacrificial layer, and the first layer and the first sacrificial layer are processed using the first resist mask to form an island-shaped first layer. Subsequently, a second layer (which can be referred to as an EL layer or a part of an EL layer) including a light-emitting layer emitting light of a second color is formed in an island shape using a second sacrificial layer and a second resist mask, similar to the first layer.

[0040] As described above, in the manufacturing method of a display device according to one embodiment of the present invention, the island-shaped EL layer is formed by forming the EL layer over the entire surface and then processing it, rather than by using a fine metal mask. Therefore, it is possible to realize a high-definition display device or a display device with a high aperture ratio, which has been difficult to achieve until now. Furthermore, since the EL layer can be formed separately for each color, it is possible to realize a display device with extremely vivid, high contrast, and high display quality. Furthermore, by providing a sacrificial layer on the EL layer, damage to the EL layer during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-emitting device.

[0041] Regarding the spacing between adjacent light-emitting devices, it is difficult to make it less than 10 μm using a formation method that uses, for example, a metal mask, but with the above method, it is possible to narrow it to 3 μm or less, 2 μm or less, or even 1 μm or less.

[0042] Furthermore, the pattern of the EL layer itself (also known as the processing size) can be made much smaller than when a metal mask is used. Furthermore, for example, when a metal mask is used to separately fabricate an EL layer, thickness variations occur between the center and edges of the EL layer, resulting in a smaller effective area that can be used as a light-emitting region relative to the area of ​​the EL layer. On the other hand, with the above-described fabrication method, a film formed to a uniform thickness is processed, so island-shaped EL layers can be formed with a uniform thickness. Therefore, even with a fine pattern, almost the entire area can be used as a light-emitting region. This makes it possible to fabricate a display device that combines high definition and a high aperture ratio.

[0043] After forming the EL layers that emit light of each color, the sacrificial layer remaining on each EL layer can be used as a hard mask to process the conductive film to form pixel electrodes. This eliminates the need for a separate mask to form the pixel electrodes in an island shape, thereby reducing the manufacturing cost of the display device. Furthermore, this eliminates the need for an insulating layer between the pixel electrodes and the EL layers to cover the edges of the pixel electrodes, allowing for extremely narrow spacing between adjacent light-emitting devices. This allows for higher definition or higher resolution of the display device.

[0044] Here, the first layer and the second layer each include at least a light-emitting layer and preferably consist of multiple layers. Specifically, it is preferable to have one or more layers on the light-emitting layer. By having another layer between the light-emitting layer and the sacrificial layer, it is possible to prevent the light-emitting layer from being exposed 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 device. Therefore, it is preferable that the first layer and the second layer each include a light-emitting layer and a carrier transport layer on the light-emitting layer.

[0045] In light-emitting devices emitting light of different colors, it is not necessary to separately fabricate all layers constituting the EL layer; some layers can be formed in the same process. In a method for fabricating a display device according to one embodiment of the present invention, some layers constituting the EL layer are formed in an island shape for each color, and then the sacrificial layer is removed. The remaining layers constituting the EL layer and a common electrode (also referred to as an upper electrode) are formed in common to the light-emitting devices of each color. For example, a carrier injection layer and a common electrode can be formed in common to the light-emitting devices of each color. Meanwhile, the carrier injection layer is often a relatively highly conductive layer among the EL layers. Therefore, contact between the carrier injection layer and the side surface of the island-shaped EL layer or the side surface of the pixel electrode may cause a short circuit in the light-emitting device. Even when the carrier injection layer is formed in an island shape and a common electrode is formed in common to the light-emitting devices of each color, contact between the common electrode and the side surface of the EL layer or the side surface of the pixel electrode may cause a short circuit in the light-emitting device.

[0046] Therefore, the display device of one embodiment of the present invention has a sidewall (also referred to as a sidewall, a sidewall protective layer, a sidewall insulating film, an insulating layer, or the like) that covers the side surfaces of the island-shaped light-emitting layer and the side surfaces of the pixel electrode.

[0047] This prevents some of the island-shaped EL layers and the pixel electrode from coming into contact with the carrier injection layer or the common electrode, thereby preventing short circuits in the light-emitting device and improving the reliability of the light-emitting device.

[0048] A display device of one embodiment of the present invention includes a pixel electrode functioning as an anode; a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer, each of which has an island shape and is provided in this order over the pixel electrode; sidewalls provided so as to cover side surfaces of the pixel electrode, the hole injection layer, the hole transport layer, the light-emitting layer, and the electron transport layer; an electron injection layer provided over the electron transport layer; and a common electrode provided over the electron injection layer and functioning as a cathode.

[0049] Alternatively, a display device of one embodiment of the present invention includes a pixel electrode that functions as a cathode; an electron-injection layer, an electron-transport layer, a light-emitting layer, and a hole-transport layer that are provided in this order over the pixel electrode, each of which has an island shape; sidewalls that are provided so as to cover side surfaces of the pixel electrode, the electron-injection layer, the electron-transport layer, the light-emitting layer, and the hole-transport layer; a hole-injection layer that is provided over the hole-transport layer; and a common electrode that is provided over the hole-injection layer and functions as an anode.

[0050] Alternatively, a display device according to one embodiment of the present invention includes a pixel electrode, a first light-emitting unit on the pixel electrode, an intermediate layer on the first light-emitting unit, a second light-emitting unit on the intermediate layer, sidewalls provided so as to cover side surfaces of the pixel electrode, the first light-emitting unit, the intermediate layer, and the second light-emitting unit, and a common electrode provided on the second light-emitting unit. Note that one or both of an electron-transport layer and an electron-injection layer may be provided between the second light-emitting unit and the common electrode as a layer common to light-emitting devices of each color.

[0051] With such a structure, a display device with high definition or resolution and high reliability can be manufactured.

[0052] [Example of display device configuration] 1A and 1B show a display device according to one embodiment of the present invention.

[0053] 1A shows a top view of a display device 100. The display device 100 has a display section in which a plurality of pixels 110 are arranged in a matrix, and a connection section 140 outside the display section. One pixel 110 is composed of three subpixels, 110a, 110b, and 110c. The connection section 140 can also be called a cathode contact section.

[0054] The top surface shape of the sub-pixel shown in FIG. 1A corresponds to the top surface shape of the light-emitting region.

[0055] Furthermore, the circuit layout constituting the subpixel is not limited to the range of the subpixel shown in Fig. 1A and may be located outside of it. For example, the transistor of the subpixel 110a may be located within the range of the subpixel 110b shown in Fig. 1A, or part or all of the transistor may be located outside the range of the subpixel 110a.

[0056] 1A shows the subpixels 110a, 110b, and 110c as having equal or approximately equal aperture ratios (sizes, or light-emitting region sizes), but this is not a limitation of the present invention. The aperture ratios of the subpixels 110a, 110b, and 110c can be determined as appropriate. The aperture ratios of the subpixels 110a, 110b, and 110c may be different from one another, or two or more of the subpixels 110a, 110b, and 110c may be equal or approximately equal.

[0057] 1A shows an example in which subpixels of different colors are arranged side by side in the X direction, and subpixels of the same color are arranged side by side in the Y direction. Note that subpixels of different colors may also be arranged side by side in the Y direction, and subpixels of the same color may also be arranged side by side in the X direction.

[0058] 1A shows an example in which the connection unit 140 is located below the display unit when viewed from above, but this is not particularly limited. The connection unit 140 only needs to be located in at least one of the upper, right, left, and lower sides of the display unit when viewed from above, and may be located so as to surround all four sides of the display unit. Furthermore, the connection unit 140 may be singular or plural.

[0059] FIG. 1B shows a cross-sectional view taken along the dashed line X1-X2 in FIG. 1A.

[0060] 1B, display device 100 has light-emitting devices 130a, 130b, and 130c provided on transistor-containing layer 101, and protective layers 131 and 132 provided to cover these light-emitting devices. Substrate 120 is bonded to protective layer 132 with resin layer 119. Sidewalls 121 are provided in the regions between adjacent light-emitting devices.

[0061] The display device of one embodiment of the present invention may be any of a top-emission type that emits light in a direction opposite to a substrate on which a light-emitting device is formed, a bottom-emission type that emits light toward a substrate on which a light-emitting device is formed, and a dual-emission type that emits light from both sides.

[0062] The transistor-containing layer 101 may have a stacked structure in which, for example, a plurality of transistors are provided on a substrate and an insulating layer is provided to cover these transistors. The transistor-containing layer 101 may have a recess between adjacent light-emitting devices. For example, a recess may be provided in an insulating layer located on the outermost surface of the transistor-containing layer 101. A configuration example of the transistor-containing layer 101 will be described later in Embodiment 2.

[0063] The light emitting devices 130a, 130b, and 130c each emit light of a different color, and preferably emit light of three colors, for example, red (R), green (G), and blue (B).

[0064] A light-emitting device has an EL layer between a pair of electrodes. In this specification and the like, one of the pair of electrodes may be referred to as a pixel electrode and the other as a common electrode.

[0065] A light-emitting device has a pair of electrodes, one of which functions as an anode and the other as a cathode. In the following, an example will be described in which the pixel electrode functions as the anode and the common electrode functions as the cathode.

[0066] The light-emitting device 130a includes a pixel electrode 111a on the transistor-containing layer 101, an island-shaped first layer 113a on the pixel electrode 111a, an electron injection layer 114 covering the top and side surfaces of the island-shaped first layer 113a, and a common electrode 115 on the electron injection layer 114. The first layer 113a includes a first hole injection layer 181a on the pixel electrode 111a, a first hole transport layer 182a on the first hole injection layer 181a, a first light-emitting layer 183a on the first hole transport layer 182a, and a first electron transport layer 184a on the first light-emitting layer 183a. In the light-emitting device 130a, the first layer 113a and the electron injection layer 114 can be collectively referred to as an EL layer.

[0067] Light-emitting device 130b includes a pixel electrode 111b on transistor-containing layer 101, an island-shaped second layer 113b on pixel electrode 111b, an electron injection layer 114 covering the top and side surfaces of island-shaped second layer 113b, and a common electrode 115 on electron injection layer 114. Second layer 113b includes a second hole injection layer 181b on pixel electrode 111b, a second hole transport layer 182b on second hole injection layer 181b, a second light-emitting layer 183b on second hole transport layer 182b, and a second electron transport layer 184b on second light-emitting layer 183b. In light-emitting device 130b, second layer 113b and electron injection layer 114 can be collectively referred to as an EL layer.

[0068] The light-emitting device 130c includes a pixel electrode 111c on the transistor-containing layer 101, an island-shaped third layer 113c on the pixel electrode 111c, an electron injection layer 114 covering the top and side surfaces of the island-shaped third layer 113c, and a common electrode 115 on the electron injection layer 114. The third layer 113c includes a third hole injection layer 181c on the pixel electrode 111c, a third hole transport layer 182c on the third hole injection layer 181c, a third light-emitting layer 183c on the third hole transport layer 182c, and a third electron transport layer 184c on the third light-emitting layer 183c. In the light-emitting device 130c, the third layer 113c and the electron injection layer 114 can be collectively referred to as an EL layer.

[0069] The common electrode shared by the light emitting devices of each color is electrically connected to the conductive layer provided in the connection section 140 .

[0070] Of the pixel electrode and the common electrode, the electrode from which light is extracted is preferably made of a conductive film that transmits visible light, and the electrode from which light is not extracted is preferably made of a conductive film that reflects visible light.

[0071] The pair of electrodes (pixel electrode and common electrode) of the light-emitting device can be formed from a metal, an alloy, an electrically conductive compound, a mixture thereof, etc. Specific examples include indium tin oxide (In-Sn oxide, also referred to as ITO), In-Si-Sn oxide (also referred to as ITSO), indium zinc oxide (In-Zn oxide), In-W-Zn oxide, an aluminum alloy (aluminum alloy) such as an alloy of aluminum, nickel, and lanthanum (Al-Ni-La), and an alloy of silver, palladium, and copper (Ag-Pd-Cu, also referred to as APC). Other examples of usable materials include 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), and neodymium (Nd), as well as alloys containing these metals in combination. Other examples include rare earth metals such as elements belonging to Groups 1 and 2 of the periodic table (e.g., lithium (Li), cesium (Cs), calcium (Ca), and strontium (Sr)), europium (Eu), and ytterbium (Yb), as well as alloys containing these metals in combination, graphene, and the like.

[0072] A light-emitting device preferably has a micro-optical resonator (microcavity) structure. Therefore, one of a pair of electrodes of the light-emitting device preferably has a transmissive and reflective electrode for visible light, and the other preferably has a reflective electrode for visible light. By having a microcavity structure in the light-emitting device, the light emitted from the light-emitting layer can be resonated between the two electrodes, thereby intensifying the light emitted from the light-emitting device.

[0073] The semi-transmitting and semi-reflective electrode may have a laminated structure of a reflective electrode and an electrode that is transparent to visible light (also called a transparent electrode).

[0074] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode with a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more for a light-emitting device. The visible light reflectance of the semi-transparent / semi-reflective electrode is 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes is 1×10 -2 Ωcm or less is preferable.

[0075] The first layer 113a, the second layer 113b, and the third layer 113c are each provided in an island shape. The first layer 113a, the second layer 113b, and the third layer 113c each have a light-emitting layer. It is preferable that the first layer 113a, the second layer 113b, and the third layer 113c each have a light-emitting layer that emits light of a different color.

[0076] The light-emitting layer is a layer containing a light-emitting substance. The light-emitting layer can contain one or more light-emitting substances. As the light-emitting substance, a substance that emits light of a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red is appropriately used. Furthermore, a substance that emits near-infrared light can also be used as the light-emitting substance.

[0077] Examples of light-emitting materials include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence (TADF) materials, and quantum dot materials.

[0078] 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.

[0079] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, a pyrazine skeleton, or a pyridine skeleton; organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand; platinum complexes; and rare earth metal complexes.

[0080] The light-emitting layer may contain one or more organic compounds (host materials, assist materials, etc.) in addition to a light-emitting substance (guest material). One or more organic compounds may be a hole-transporting material or an electron-transporting material, or both. Alternatively, a bipolar material or a TADF material may be used as the one or more organic compounds.

[0081] The light-emitting layer preferably contains, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material that are a combination that easily forms an exciplex. This configuration allows for efficient emission using Exciplex-Triplet Energy Transfer (ExTET), which is energy transfer from the exciplex to the light-emitting material (phosphorescent material). By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material, the energy transfer becomes smooth, allowing for efficient emission. This configuration simultaneously enables high efficiency, low-voltage operation, and long life of the light-emitting device.

[0082] The first layer 113a, the second layer 113b, and the third layer 113c may further include a layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a hole-blocking material, a substance with high electron-transport properties, a substance with high electron-injection properties, an electron-blocking material, a bipolar substance (a substance with high electron-transport properties and high hole-transport properties), or the like, as a layer other than the light-emitting layer.

[0083] The light-emitting device can be made of either a low-molecular-weight compound or a high-molecular-weight compound, and may contain an inorganic compound. The layers constituting the light-emitting device can be formed by a method such as vapor deposition (including vacuum vapor deposition), transfer, printing, inkjet printing, or coating.

[0084] For example, the first layer 113a, the second layer 113b, and the third layer 113c may each include one or more of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0085] The EL layer may include one or more of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer, which may be formed in common by the light-emitting devices of each color. It is also possible to form all layers of the EL layer separately for each color. In other words, the EL layer does not need to include a layer that is formed in common by the light-emitting devices of each color.

[0086] In the display device 100 shown in FIG. 1B, the first layer 113a includes a first light-emitting layer 183a and a first electron-transport layer 184a on the first light-emitting layer 183a. Similarly, the second layer 113b includes a second light-emitting layer 183b and a second electron-transport layer 184b on the second light-emitting layer 183b, and the third layer 113c includes a third light-emitting layer 183c and a third electron-transport layer 184c on the third light-emitting layer 183c. This prevents the light-emitting layer from being exposed to the outermost surface during the manufacturing process of the display device 100, thereby reducing damage to the light-emitting layer. This improves the reliability of the light-emitting device.

[0087] The pixel electrodes 111a, 111b, 111c, the first layer 113a, the second layer 113b, and the third layer 113c are covered with side walls 121, and the side walls 121 are located between these layers and the electron injection layer 114 (or the common electrode 115). This prevents the electron injection layer 114 (or the common electrode 115) from coming into contact with any of the side surfaces of the pixel electrodes 111a, 111b, 111c, the first layer 113a, the second layer 113b, and the third layer 113c, thereby preventing short circuits in the light-emitting device.

[0088] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a material with high hole injection properties, such as an aromatic amine compound and a composite material containing a hole transport material and an acceptor material (electron acceptor material).

[0089] 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 that contains a hole transport material. The hole transport material is a material having a concentration of 1×10 -6 cm 2A material having a hole mobility of 1 / Vs or more is preferred. Note that other materials can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, a material having a high hole transporting property, such as a π-electron-rich heteroaromatic compound (e.g., a carbazole derivative, a thiophene derivative, a furan derivative, etc.) or an aromatic amine (a compound having an aromatic amine skeleton), is preferred.

[0090] 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 that contains an electron transporting material. The electron transporting material is a material having a molecular weight of 1×10 -6 cm 2 A substance having an electron mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher electron transporting property than holes. Examples of electron-transporting materials that can be used include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, and 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 including nitrogen-containing heteroaromatic compounds.

[0091] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a material with high electron injection properties. Examples of the material with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the material with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0092] The electron injection layer may be formed of, for example, lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF x, where X is an arbitrary number), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatolithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviation: LiPPP), lithium oxide (LiO x The electron injection layer may be formed of an alkali metal, an alkaline earth metal, such as cesium carbonate, or a compound thereof. The electron injection layer may have a stacked structure of two or more layers. For example, the stacked structure may have a structure in which lithium fluoride is used in the first layer and ytterbium is provided in the second layer.

[0093] Alternatively, an electron transporting material may be used for the electron injection layer. For example, a compound having an unshared electron pair and an electron-deficient heteroaromatic ring may 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), and a triazine ring may be used.

[0094] The organic compound having an unshared electron pair preferably has a lowest unoccupied molecular orbital (LUMO) of -3.6 eV to -2.3 eV. Generally, the highest occupied molecular orbital (HOMO) level and the LUMO level of an organic compound can be estimated by cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, or the like.

[0095] Examples of organic compounds with lone electron pairs include 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-bis(naphthalen-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'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPYTz). NBPhen has a higher glass transition temperature (Tg) and better heat resistance than BPhen.

[0096] The sidewall 121 can be formed using at least one of inorganic insulating films such as an insulating oxide film, an insulating nitride film, an insulating oxynitride film, and an insulating nitride oxide film. Examples of insulating oxide films include a silicon oxide film, an aluminum oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, and a tantalum oxide film. Examples of insulating nitride films include a silicon nitride film and an aluminum nitride film. Examples of insulating oxynitride films include a silicon oxynitride film and an aluminum oxynitride film. Examples of insulating nitride oxide films include a silicon nitride oxide film and an aluminum nitride oxide film.

[0097] It is preferable to provide protective layers 131 and 132 on the light emitting devices 130a, 130b, and 130c. By providing the protective layers 131 and 132, the reliability of the light emitting devices can be improved.

[0098] There is no limitation on the conductivity of the protective layers 131 and 132. The protective layers 131 and 132 can be made of at least one of an insulating film, a semiconductor film, and a conductive film.

[0099] The protective layers 131 and 132 have inorganic films, which can prevent oxidation of the common electrode 115 and prevent impurities (moisture, oxygen, etc.) from entering the light-emitting devices 130a, 130b, and 130c, thereby suppressing deterioration of the light-emitting devices and improving the reliability of the display device.

[0100] The protective layers 131 and 132 can be made of inorganic insulating films such as an insulating oxide film, an insulating nitride film, an insulating oxynitride film, and an insulating nitride oxide film. Examples of insulating oxide films include a silicon oxide film, an aluminum oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, and a tantalum oxide film. Examples of insulating nitride films include a silicon nitride film and an aluminum nitride film. Examples of insulating oxynitride films include a silicon oxynitride film and an aluminum oxynitride film. Examples of insulating nitride oxide films include a silicon nitride oxide film and an aluminum nitride oxide film.

[0101] In this specification and elsewhere, an oxynitride refers to a material having a composition in which oxygen is contained in a larger amount than nitrogen, and a nitride oxide refers to a material having a composition in which nitrogen is contained in a larger amount than oxygen.

[0102] Each of the protective layers 131 and 132 preferably includes an insulating nitride film or an insulating nitride oxide film, and more preferably includes an insulating nitride film.

[0103] Alternatively, an inorganic film containing In-Sn oxide (also referred to as ITO), In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or indium gallium zinc oxide (In-Ga-Zn oxide, also referred to as IGZO) may be used for the protective layers 131 and 132. The inorganic film preferably has high resistance, specifically, preferably has higher resistance than the common electrode 115. The inorganic film may further contain nitrogen.

[0104] When light emitted from the light-emitting device is extracted through the protective layers 131 and 132, it is preferable that the protective layers 131 and 132 have high transparency to visible light. For example, ITO, IGZO, and aluminum oxide are preferable because they are inorganic materials that have high transparency to visible light.

[0105] The protective layers 131 and 132 may be, for example, a laminated structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a laminated structure of an aluminum oxide film and an IGZO film on the aluminum oxide film. By using such a laminated structure, impurities (water, oxygen, etc.) can be prevented from entering the EL layer side.

[0106] Furthermore, the protective layers 131 and 132 may include an organic film. For example, the protective layer 132 may include both an organic film and an inorganic film.

[0107] Different film formation methods may be used for the protective layer 131 and the protective layer 132. Specifically, the protective layer 131 may be formed by atomic layer deposition (ALD), and the protective layer 132 may be formed by sputtering.

[0108] The upper end portions of the pixel electrodes 111a, 111b, and 111c are not covered with an insulating layer, which allows the distance between adjacent light-emitting devices to be extremely narrow, thereby enabling a high-definition or high-resolution display device.

[0109] In this specification, etc., a device fabricated using a metal mask or FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. Also, in this specification, etc., a device fabricated without using a metal mask or FMM may be referred to as a device with an MML (metal maskless) structure.

[0110] In this specification, a structure in which different light-emitting layers are formed or different light-emitting layers are painted for each color light-emitting device (here, blue (B), green (G), and red (R)) may be referred to as an SBS (Side By Side) structure. In this specification, a light-emitting device that can emit white light may be referred to as a white light-emitting device. A white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0111] Light-emitting devices can be broadly divided into single-structure and tandem-structure devices. A single-structure device has one light-emitting unit between a pair of electrodes, and the light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, two or more light-emitting layers may be selected so that the light emitted from each of the two or more light-emitting layers has a complementary color relationship. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary, a configuration in which the entire light-emitting device emits white light can be obtained. The same applies to light-emitting devices having three or more light-emitting layers.

[0112] A tandem-structured device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. To obtain white light, light from the light-emitting layers of the multiple light-emitting units may be combined to obtain white light. The configuration for obtaining white light is the same as that of the single-structured device. In a tandem-structured device, it is preferable to provide an intermediate layer such as a charge-generating layer between the multiple light-emitting units.

[0113] Furthermore, when comparing the above-mentioned white light-emitting device (single structure or tandem structure) with a light-emitting device having an SBS structure, the light-emitting device having an SBS structure can reduce power consumption compared to the white light-emitting device. If you want to keep power consumption low, it is preferable to use a light-emitting device having an SBS structure. On the other hand, the manufacturing process of a white light-emitting device is simpler than that of a light-emitting device having an SBS structure, so it is preferable because it can reduce manufacturing costs or increase manufacturing yields.

[0114] The display device of this embodiment can reduce the distance between light-emitting devices. Specifically, the distance between light-emitting devices can be set to 1 μm or less, preferably 500 nm or less, and 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, the distance between the side surface of the first layer 113a and the side surface of the second layer 113b or the distance between the side surface of the second layer 113b and the side surface of the third layer 113c has a region of 1 μm or less, preferably a region of 0.5 μm (500 nm) or less, and more preferably a region of 100 nm or less.

[0115] A light-shielding layer may be provided on the surface of substrate 120 facing resin layer 119. Various optical members may be disposed on the outside of substrate 120. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light-collecting film. The outside of substrate 120 may also be provided with an anti-static film that prevents dust from adhering, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that prevents scratches from occurring during use, an impact absorbing layer, etc.

[0116] The substrate 120 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, or the like. A material that transmits light is used for the substrate on the side from which light from the light-emitting device is extracted. Using a flexible material for the substrate 120 increases the flexibility of the display device, making it possible to realize a flexible display. A polarizing plate may also be used for the substrate 120.

[0117] The substrate 120 can be made of polyester resin such as polyethylene terephthalate (PET) or 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, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. The substrate 120 can also be made of glass having a thickness sufficient to provide flexibility.

[0118] When a circularly polarizing plate is superimposed on a display device, it is preferable that the display device has a substrate with high optical isotropy. A substrate with high optical isotropy has small birefringence (or a small amount of birefringence).

[0119] The absolute value of the retardation (phase difference) of a substrate having high optical isotropy is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0120] Examples of films with high optical isotropy include triacetyl cellulose (TAC, also known as cellulose triacetate) films, cycloolefin polymer (COP) films, cycloolefin copolymer (COC) films, and acrylic films.

[0121] Furthermore, when a film is used as a substrate, the film may absorb water, causing deformation such as wrinkles 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 preferably 0.1% or less, and even more preferably 0.01% or less.

[0122] The resin layer 119 can be made of various curable adhesives, such as a photo-curable adhesive (e.g., an ultraviolet curable adhesive), a reactive curable adhesive, a thermosetting adhesive, or an anaerobic adhesive. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. In particular, a material with low moisture permeability, such as epoxy resin, is preferable. Alternatively, a two-component resin may be used. Alternatively, an adhesive sheet or the like may be used.

[0123] Materials that can be used for conductive layers such as the gate, source, and drain of a transistor, as well as various wirings and electrodes that constitute a display device include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, and alloys containing these metals as main components, etc. Films containing these materials can be used as a single layer or a stacked layer structure.

[0124] Examples of light-transmitting conductive materials include conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metal materials, can be used. Alternatively, nitrides of such metal materials (e.g., titanium nitride) can be used. When using metal materials or alloy materials (or their nitrides), it is preferable to thin them sufficiently to ensure light-transmitting properties. A stacked film of the above materials can also be used as the conductive layer. For example, a stacked film of an alloy of silver and magnesium and indium tin oxide is preferable because it can enhance conductivity. These materials can also be used for conductive layers such as various wirings and electrodes constituting a display device, and conductive layers (conductive layers functioning as pixel electrodes or common electrodes) in light-emitting devices.

[0125] 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 oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0126] [Example 1 of a method for manufacturing a display device] Next, an example of a manufacturing method of a display device will be described with reference to Figures 2 to 8. Figures 2A to 2C are top views showing the manufacturing method of a display device. Figures 3A to 3C show cross-sectional views taken along dashed lines X1-X2 and Y1-Y2 in Figure 1A side by side. Figures 4 to 8 are similar to Figure 3.

[0127] Thin films (insulating films, semiconductor films, conductive films, etc.) that make up display devices can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), and ALD. CVD methods include plasma enhanced chemical vapor deposition (PECVD) and thermal CVD. One type of thermal CVD method is metal organic chemical vapor deposition (MOCVD).

[0128] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, and knife coating.

[0129] In particular, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet printing can be used to fabricate light-emitting devices. 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). In particular, functional layers included in the EL layer (e.g., hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer) can be formed by vapor deposition (e.g., vacuum deposition), coating methods (e.g., dip coating, die coating, bar coating, spin coating, spray coating), printing methods (e.g., inkjet printing, screen printing, offset printing, flexography, gravure printing, microcontact printing, etc.).

[0130] Furthermore, when processing the thin film that constitutes the display device, a photolithography method or the like can be used. Alternatively, the thin film may be processed by a nanoimprint method, a sandblasting method, a lift-off method, or the like. Furthermore, the island-shaped thin film may be directly formed by a film formation method using a shielding mask such as a metal mask.

[0131] There are two typical photolithography methods: one is to form a resist mask on the thin film to be processed, process the thin film by etching or the like, and then remove the resist mask; the other is to form a photosensitive thin film, and then process the thin film into the desired shape by exposure and development.

[0132] 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 of these. Other light sources that can be used include ultraviolet light, KrF laser light, and ArF laser light. Exposure can also be performed using immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays can also be used as the light used for exposure. Instead of light used for exposure, an electron beam can also be used. Extreme ultraviolet light, X-rays, or an electron beam are preferred because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0133] For etching the thin film, dry etching, wet etching, sandblasting, or the like can be used.

[0134] First, as shown in FIG. 3A, a conductive film 111 is formed over a layer 101 including a transistor.

[0135] Then, a first hole injection layer 181A, a first hole transport layer 182A, a first light-emitting layer 183A, and a first electron transport layer 184A are formed in this order on the conductive film 111, and a first sacrificial layer 118A is formed on the first electron transport layer 184A. As shown in FIG. 3A , in the cross-sectional view taken along the line Y1-Y2, the ends of the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A on the connection portion 140 side are positioned more inward than the end of the first sacrificial layer 118A. For example, by using a mask for defining the film formation area (also called an area mask or a rough metal mask to distinguish it from a fine metal mask), it is possible to change the regions where the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, and the first sacrificial layer 118A are formed. In one embodiment of the present invention, a light-emitting device is formed using a resist mask, and by combining it with an area mask as described above, the light-emitting device can be manufactured by a relatively simple process.

[0136] The conductive film 111 is a layer that will be processed later to become the pixel electrodes 111a, 111b, and 111c and the conductive layer 123. Therefore, the structure applicable to the pixel electrodes described above can be applied to the conductive film 111. The conductive film 111 can be formed by, for example, sputtering or vacuum evaporation.

[0137] The first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A are layers that will later become the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, and the first electron transport layer 184a, respectively. Therefore, the configurations applicable to the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, and the first electron transport layer 184a described above can be applied to these layers. The first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A can be formed by a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, a coating method, or the like. The first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A may each be formed using a premix material. In this specification and the like, a premix material refers to a composite material in which multiple materials are blended or mixed in advance.

[0138] The first sacrificial layer 118A is made of a film that is highly resistant to processing conditions, specifically a film with a high etching selectivity, for the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A, as well as the second hole injection layer 181B, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B, the third hole injection layer 181C, the third hole transport layer 182C, the third light-emitting layer 183C, and the third electron transport layer 184C, which will be formed in a later step. The first sacrificial layer 118A may have a single-layer structure or a multilayer structure.

[0139] The first sacrificial layer 118A can be formed by, for example, sputtering, ALD (including thermal ALD and PEALD), or vacuum deposition. A formation method that causes less damage to the EL layer is preferred, and it is preferable to form the first sacrificial layer 118A using ALD or vacuum deposition rather than sputtering. The first sacrificial layer 118A is formed at a temperature lower than the heat-resistant temperature of the EL layer (typically 200°C or lower, preferably 100°C or lower, and more preferably 80°C or lower).

[0140] It is preferable to use a film that can be removed by wet etching for the first sacrificial layer 118A. By using wet etching, damage to the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A during processing of the first sacrificial layer 118A can be reduced compared to when dry etching is used.

[0141] In the process of processing the various sacrificial layers in the manufacturing method of the display device of this embodiment, it is desirable that the layers constituting the EL layer (such as the hole injection layer, hole transport layer, light-emitting layer, and electron transport layer) are not easily processed, and that the various sacrificial layers are not easily processed in the process of processing the layers constituting the EL layer. It is desirable to select the material and processing method of the sacrificial layer and the processing method of the EL layer taking these factors into consideration.

[0142] The first sacrificial layer 118A may be, for example, a metal film, an alloy film, a metal oxide film, a semiconductor film, or an inorganic film such as an inorganic insulating film.

[0143] The first sacrificial layer 118A can be made of a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or an alloy material containing such a metal material.

[0144] The first sacrificial layer 118A can be made of a metal oxide such as In-Ga-Zn oxide. For example, an In-Ga-Zn oxide film can be formed as the first sacrificial layer 118A by sputtering. Other examples include indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), and indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide). Alternatively, silicon-containing indium tin oxide can be used.

[0145] Instead of the gallium, an element M (M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) may be used.

[0146] The first sacrificial layer 118A can be made of any of the various inorganic insulating films that can be used for the protective layers 131 and 132. In particular, oxide insulating films are preferable because they have higher adhesion to the EL layer than nitride insulating films. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used for the first sacrificial layer 118A. For example, an aluminum oxide film can be formed as the first sacrificial layer 118A using the ALD method. Using the ALD method is preferable because it can reduce damage to the underlying layer (particularly the EL layer, etc.).

[0147] For example, the first sacrificial layer 118A may have a stacked structure of an In-Ga-Zn oxide film formed by sputtering and an aluminum oxide film formed on the In-Ga-Zn oxide film by ALD. Alternatively, the first sacrificial layer 118A may have a stacked structure of an aluminum oxide film formed by ALD and an In-Ga-Zn oxide film formed on the aluminum oxide film by sputtering. Alternatively, the first sacrificial layer 118A may have a single-layer structure of an aluminum oxide film formed by ALD.

[0148] 3B, a resist mask 190a is formed on the first sacrificial layer 118A. The resist mask can be formed by applying a photosensitive resin (photoresist) and then performing exposure and development.

[0149] 2A, the resist mask 190a is provided in a position that overlaps with an area that will later become the subpixel 110a. Preferably, the resist mask 190a has an island-shaped pattern for each subpixel 110a. Alternatively, the resist mask 190a may have a strip-shaped pattern for multiple subpixels 110a that are aligned in a line (aligned in the Y direction in FIG. 2A).

[0150] Note that the resist mask 190a may also be provided in a position overlapping with a region that will later become the connection portion 140. This can prevent the region of the conductive film 111 that will later become the conductive layer 123 from being damaged during the manufacturing process of the display device.

[0151] Next, a portion of the first sacrificial layer 118A is removed using the resist mask 190a. Furthermore, a portion of the first hole injection layer 181A, a portion of the first hole transport layer 182A, a portion of the first light-emitting layer 183A, and a portion of the first electron transport layer 184A are removed. The stacked structure from the first hole injection layer 181A to the first electron transport layer 184A may be processed using the resist mask 190a, or the first sacrificial layer 118a obtained by processing the first sacrificial layer 118A may be used.

[0152] This allows the removal of the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, and the first sacrificial layer 118A in areas that are not overlapped by the resist mask 190a.

[0153] In this example manufacturing method 1, a stacked structure is applied to the first sacrificial layer 118A, some layers are processed using a resist mask 190a, and after removing the resist mask 190a, the remaining layers are processed using the some layers as a hard mask.

[0154] For example, after processing a portion of first sacrificial layer 118A using resist mask 190a, resist mask 190a is removed by ashing using oxygen plasma or the like. At this time, the remaining layers of first sacrificial layer 118A are located on the outermost surface, and first hole injection layer 181A, first hole transport layer 182A, first light-emitting layer 183A, and first electron transport layer 184A are not exposed. Therefore, damage to first hole injection layer 181A, first hole transport layer 182A, first light-emitting layer 183A, and first electron transport layer 184A can be suppressed in the process of removing resist mask 190a. Then, using a portion of the processed first sacrificial layer 118A as a hard mask, the remaining layers of the first sacrificial layer 118A, the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A can be processed.

[0155] 3C , in a region corresponding to the subpixel 110a, a stacked structure of the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, the first electron transport layer 184a, and the first sacrificial layer 118a remains on the conductive film 111. Note that the stacked structure of the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, and the first electron transport layer 184a is also referred to as the first layer 113a. In addition, in a region corresponding to the connection portion 140, the conductive film 111 is exposed.

[0156] Note that the resist mask 190a may be used to remove part of the first hole injection layer 181A, part of the first hole transport layer 182A, part of the first light-emitting layer 183A, and part of the first electron transport layer 184A. The resist mask 190a may then be removed. Alternatively, as described later in Fabrication Method Example 3 (FIG. 13), the process may proceed to the next step without removing the resist mask 190a.

[0157] The first sacrificial layer 118A can be processed by wet etching or dry etching, and is preferably processed by anisotropic etching.

[0158] Compared to the case of using dry etching, the use of wet etching can reduce damage to first hole injection layer 181A, first hole transport layer 182A, first light-emitting layer 183A, and first electron transport layer 184A during processing of first sacrificial layer 118A. When using wet etching, it is preferable to use a chemical solution such as a developer, a tetramethylammonium hydroxide (TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0159] Furthermore, when dry etching is used, deterioration of first hole injection layer 181A, first hole transport layer 182A, first light-emitting layer 183A, and first electron transport layer 184A can be suppressed by not using a gas containing oxygen as an etching gas. When dry etching is used, it is preferable to use a gas containing a noble gas (also called a rare gas) such as CF4, C4F8, SF6, CHF3, Cl2, HO, BCl3, or He as an etching gas.

[0160] The first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A are preferably processed by anisotropic etching. Anisotropic dry etching is particularly preferred. The etching gas preferably includes a nitrogen-containing gas, a hydrogen-containing gas, a noble gas, a nitrogen and argon-containing gas, or a nitrogen and hydrogen-containing gas. By not using an oxygen-containing gas as the etching gas, deterioration of the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A can be suppressed.

[0161] Alternatively, a gas containing oxygen may be used as the etching gas. The inclusion of oxygen in the etching gas can increase the etching rate. Therefore, etching can be performed under low power conditions while maintaining a sufficiently high etching rate. This can reduce damage to the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A. Furthermore, problems such as adhesion of reaction products that occur during etching can be reduced.

[0162] 4A, a second hole injection layer 181B, a second hole transport layer 182B, a second light-emitting layer 183B, and a second electron transport layer 184B are formed in this order on the first sacrificial layer 118a and the conductive film 111, and a second sacrificial layer 118B is formed on the second electron transport layer 184B. As shown in FIG. 4A, in the cross-sectional view between Y1 and Y2, the ends of the second hole injection layer 181B, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B on the connection portion 140 side are positioned more inward than the end of the second sacrificial layer 118B.

[0163] The second hole injection layer 181B, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B are layers that will later become the second hole injection layer 181b, the second hole transport layer 182b, the second light-emitting layer 183b, and the second electron transport layer 184b, respectively. The second light-emitting layer 183b emits light of a different color from the first light-emitting layer 183a. The structures and materials that can be applied to the second hole injection layer 181b, the second hole transport layer 182b, the second light-emitting layer 183b, and the second electron transport layer 184b are similar to those of the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, and the first electron transport layer 184a, respectively. The second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B can be formed using the same method as that for the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A, respectively.

[0164] The second sacrificial layer 118B can be formed using a material that can be applied to the first sacrificial layer 118A.

[0165] Next, as shown in FIG. 4B, a resist mask 190b is formed on the second sacrificial layer 118B.

[0166] 2B, the resist mask 190b is provided in a position that overlaps with an area that will later become the sub-pixel 110b. Preferably, the resist mask 190b has an island-shaped pattern for each sub-pixel 110b. Alternatively, the resist mask 190b may have a strip-shaped pattern for multiple sub-pixels 110b that are aligned in a row.

[0167] The resist mask 190b may also be provided at a position overlapping the region that will later become the connection portion 140.

[0168] Next, a portion of the second sacrificial layer 118B is removed using the resist mask 190b. Furthermore, a portion of the second hole injection layer 181B, a portion of the second hole transport layer 182B, a portion of the second light-emitting layer 183B, and a portion of the second electron transport layer 184B are removed. The stacked structure from the second hole injection layer 181B to the second electron transport layer 184B may be processed using the resist mask 190b, or the second sacrificial layer 118b obtained by processing the second sacrificial layer 118B may be used.

[0169] This allows the removal of the regions of the second hole injection layer 181B, the second hole transport layer 182B, the second light-emitting layer 183B, the second electron transport layer 184B, and the second sacrificial layer 118B that are not overlapped with the resist mask 190b.

[0170] 4C , in a region corresponding to the subpixel 110b, a stacked layer structure of the second hole injection layer 181b, the second hole transport layer 182b, the second light-emitting layer 183b, the second electron transport layer 184b, and the second sacrificial layer 118b remains on the conductive film 111. Note that the stacked layer structure of the second hole injection layer 181b, the second hole transport layer 182b, the second light-emitting layer 183b, and the second electron transport layer 184b is also referred to as the second layer 113b. In addition, in a region corresponding to the connection portion 140, the conductive film 111 is exposed.

[0171] The second sacrificial layer 118B can be processed using a method applicable to processing the first sacrificial layer 118A. The second hole injection layer 181B, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B can be processed using a method applicable to processing the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A. The resist mask 190b can be removed by a method and at a timing applicable to removing the resist mask 190a.

[0172] 5A, a third hole injection layer 181C, a third hole transport layer 182C, a third light-emitting layer 183C, and a third electron transport layer 184C are formed in this order on the first sacrificial layer 118a, the second sacrificial layer 118b, and the conductive film 111, and a third sacrificial layer 118C is formed on the third electron transport layer 184C. As shown in FIG. 5A, in the cross-sectional view between Y1 and Y2, the ends of the third hole injection layer 181C, the third hole transport layer 182C, the third light-emitting layer 183C, and the third electron transport layer 184C on the connection portion 140 side are positioned more inward than the end of the third sacrificial layer 118C.

[0173] The third hole injection layer 181C, the third hole transport layer 182C, the third light-emitting layer 183C, and the third electron transport layer 184C are layers that will later become the third hole injection layer 181c, the third hole transport layer 182c, the third light-emitting layer 183c, and the third electron transport layer 184c, respectively. The third light-emitting layer 183c emits light of a different color from the first light-emitting layer 183a and the second light-emitting layer 183b. The configurations and materials that can be applied to the third hole injection layer 181c, the third hole transport layer 182c, the third light-emitting layer 183c, and the third electron transport layer 184c are similar to those of the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, and the first electron transport layer 184a, respectively. The third hole injection layer 181C, the third hole transport layer 182C, the third light-emitting layer 183C, and the third electron transport layer 184C can be formed using the same method as that for the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A, respectively.

[0174] The third sacrificial layer 118C can be formed using a material that can be applied to the first sacrificial layer 118A.

[0175] Next, as shown in FIG. 5B, a resist mask 190c is formed on the third sacrificial layer 118C.

[0176] As shown in FIG. 2C , the resist mask 190c is provided in a position overlapping with a region that will later become the subpixel 110c. Preferably, the resist mask 190c has an island-shaped pattern formed for each subpixel 110c. Alternatively, the resist mask 190c may have a strip-shaped pattern formed for a plurality of subpixels 110c arranged in a row. Furthermore, the resist mask 190c is also preferably provided in a position overlapping with a region that will later become the connection portion 140. Note that if at least one of the first sacrificial layer 118a and the second sacrificial layer 118b is provided in the region that will later become the connection portion 140, the resist mask 190c does not need to be provided in that region.

[0177] Next, a portion of the third sacrificial layer 118C is removed using the resist mask 190c. Furthermore, a portion of the third hole injection layer 181C, a portion of the third hole transport layer 182C, a portion of the third light-emitting layer 183C, and a portion of the third electron transport layer 184C are removed. The stacked structure from the third hole injection layer 181C to the third electron transport layer 184C may be processed using the resist mask 190c, or the third sacrificial layer 118c obtained by processing the third sacrificial layer 118C may be used.

[0178] This allows the removal of the regions of the third hole injection layer 181C, the third hole transport layer 182C, the third light emitting layer 183C, the third electron transport layer 184C, and the third sacrificial layer 118C that are not overlapped with the resist mask 190c.

[0179] 5C , in a region corresponding to the subpixel 110c, a stacked structure of a third hole injection layer 181c, a third hole transport layer 182c, a third light-emitting layer 183c, a third electron transport layer 184c, and a third sacrificial layer 118c remains on the conductive film 111. Note that the stacked structure of the third hole injection layer 181c, the third hole transport layer 182c, the third light-emitting layer 183c, and the third electron transport layer 184c is also referred to as a third layer 113c. Furthermore, in a region corresponding to the connection portion 140, a stacked structure of the conductive film 111 and the third sacrificial layer 118c on the conductive film 111 remains.

[0180] The third sacrificial layer 118C can be processed using a method applicable to processing the first sacrificial layer 118A. The third hole injection layer 181C, the third hole transport layer 182C, the third light-emitting layer 183C, and the third electron transport layer 184C can be processed using a method applicable to processing the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A. The resist mask 190c can be removed by a method and at a timing applicable to removing the resist mask 190a.

[0181] Next, as shown in FIG. 6A, the conductive film 111 is processed using the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c as hard masks to form pixel electrodes 111a, 111b, 111c, and a conductive layer 123.

[0182] As will be described later in a manufacturing method example 2, before processing the conductive film 111, sidewalls 122 covering the side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c may be formed.

[0183] When the conductive film 111 is processed, a part of the transistor-including layer 101 (specifically, the insulating layer located at the outermost surface) may be processed to form a recess. In the following description, a case where a recess is provided in the transistor-including layer 101 will be described as an example, but the recess is not necessarily provided.

[0184] Here, in order to form the conductive layer 123, it is only necessary that at least one of the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c is provided in the connecting portion 140.

[0185] The conductive film 111 can be processed by a wet etching method or a dry etching method. The conductive film 111 is preferably processed by anisotropic etching.

[0186] Next, as shown in FIG. 6B, an insulating film 121A is formed to cover the first layer 113a, the second layer 113b, the third layer 113c, the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c.

[0187] The insulating film 121A can be, for example, at least one of inorganic insulating films such as an insulating oxide film, an insulating nitride film, an insulating oxynitride film, and an insulating nitride oxide film. Examples of the insulating oxide film include a silicon oxide film, an aluminum oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, and a tantalum oxide film. Examples of the nitride insulating film include a silicon nitride film and an aluminum nitride film. Examples of the oxynitride insulating film include a silicon oxynitride film and an aluminum oxynitride film. Examples of the nitride oxide insulating film include a silicon nitride oxide film and an aluminum nitride oxide film. The insulating film 121A can have a single-layer structure or a multilayer structure.

[0188] The insulating film 121A is preferably formed by a method that causes little damage to the EL layer. The insulating film 121A is formed at a temperature lower than the heat-resistant temperature of the EL layer. For example, an aluminum oxide film can be formed as the insulating film 121A by an ALD method. The ALD method is preferable because it allows a film with high coverage to be formed. For example, a silicon oxynitride film or a silicon nitride film can be formed as the insulating film 121A by a PECVD method. Alternatively, the insulating film 121A may have a stacked structure of an aluminum oxide film formed by an ALD method and a silicon oxynitride film or a silicon nitride film formed by a PECVD method. Alternatively, the insulating film 121A may have a stacked structure of an aluminum oxide film formed by an ALD method and a silicon oxynitride film or a silicon nitride film formed by a sputtering method.

[0189] Next, as shown in FIG. 6C , the insulating film 121A is processed to form sidewalls 121. The sidewalls 121 are provided so as to cover the side surfaces of the pixel electrodes 111a, 111b, and 111c. This prevents a film (a film constituting an EL layer or a common electrode) to be formed later from coming into contact with the pixel electrodes 111a, 111b, and 111c, thereby preventing a short circuit in the light-emitting device. Furthermore, the sidewalls 121 are preferably provided so as to cover the side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c. This prevents a film to be formed later from coming into contact with the side surfaces of these layers, thereby preventing a short circuit in the light-emitting device. Furthermore, this prevents damage to the first layer 113a, the second layer 113b, and the third layer 113c in subsequent processes.

[0190] In particular, if a recess is provided in a part of the layer 101 including the transistor (specifically, the insulating layer located on the outermost surface), the entire side surfaces of the pixel electrodes 111a, 111b, and 111c can be covered with the sidewall 121, which is preferable.

[0191] The insulating film 121A is preferably processed by dry etching. The insulating film 121A is preferably processed by anisotropic etching. The insulating film 121A can be processed using an etching gas that can be used when processing the first sacrificial layer 118A. Furthermore, when processing the insulating film 121A, the EL layer is not exposed, so there is a wider range of processing methods to choose from than when processing the first sacrificial layer 118A. Specifically, when processing the insulating film 121A, a gas containing oxygen may be used as an etching gas.

[0192] 7A , the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c are removed, thereby exposing the first electron transport layer 184a on the pixel electrode 111a, the second electron transport layer 184b on the pixel electrode 111b, the third electron transport layer 184c on the pixel electrode 111c, and the conductive layer 123 at the connection portion 140.

[0193] The sacrificial layer removal process can be performed using the same method as the sacrificial layer processing process. In particular, using wet etching can reduce damage to the first layer 113a, the second layer 113b, and the third layer 113c when removing the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c compared to using dry etching.

[0194] 7B, the electron injection layer 114 is formed to cover the sidewall 121, the first layer 113a, the second layer 113b, and the third layer 113c. As shown in FIG. 7B, in the cross-sectional view between Y1 and Y2, the end of the electron injection layer 114 on the connection portion 140 side is located inside the connection portion 140, and the conductive layer 123 remains exposed.

[0195] The materials that can be used for the electron injection layer 114 are as described above. The electron injection layer 114 can be formed by a method such as a vapor deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, or a coating method. The electron injection layer 114 may also be formed using a premixed material.

[0196] The electron-injection layer 114 is provided to cover the top surfaces of the first electron-transport layer 184a, the second electron-transport layer 184b, and the third electron-transport layer 184c, as well as the top and side surfaces of the sidewall 121. If the electron-injection layer 114 has high conductivity, contact between the electron-injection layer 114 and any of the pixel electrodes 111a, 111b, and 111c may cause a short circuit in the light-emitting device. However, in the display device of one embodiment of the present invention, the sidewall 121 covers the first layer 113a, the second layer 113b, the third layer 113c, and the side surfaces of the pixel electrodes 111a, 111b, and 111c. This prevents the highly conductive electron-injection layer 114 from contacting these layers, thereby preventing a short circuit in the light-emitting device. This improves the reliability of the light-emitting device.

[0197] Then, as shown in FIG. 7C, a common electrode 115 is formed on the electron injection layer 114 and the conductive layer 123.

[0198] The above-mentioned materials can be used for the common electrode 115. The common electrode 115 can be formed by, for example, sputtering or vacuum deposition.

[0199] As shown in FIG. 8A, a fourth electron transport layer 116 may be formed so as to cover the sidewall 121, the first layer 113a, the second layer 113b, and the third layer 113c, an electron injection layer 114 may be formed on the fourth electron transport layer 116, and a common electrode 115 may be formed on the electron injection layer 114.

[0200] The materials that can be used for the fourth electron transport layer 116 are as described above. The fourth electron transport layer 116 can be formed by a method such as a vapor deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, or a coating method. The fourth electron transport layer 116 may also be formed using a premix material.

[0201] 8B and 8C, a common electrode 115 may be formed to cover the sidewall 121, the first layer 113a, the second layer 113b, and the third layer 113c. FIGS. 8B and 8C show an example in which the first layer 113a has a first electron injection layer 114a, the second layer 113b has a second electron injection layer 114b, and the third layer 113c has a third electron injection layer 114c. In other words, all layers constituting the EL layer are individually fabricated in light-emitting devices that emit light of different colors. Therefore, the EL layers of each light-emitting device are all formed in an island shape.

[0202] The common electrode 115 is provided to cover the top surfaces of the first electron-injection layer 114a, the second electron-injection layer 114b, and the third electron-injection layer 114c and the top and side surfaces of the sidewall 121. Here, contact between the common electrode 115 and any of the pixel electrodes 111a, 111b, and 111c may cause a short circuit in the light-emitting device. However, in the display device of one embodiment of the present invention, the sidewall 121 covers the first layer 113a, the second layer 113b, the third layer 113c, and the side surfaces of the pixel electrodes 111a, 111b, and 111c. This prevents the common electrode 115 from contacting these layers, thereby preventing a short circuit in the light-emitting device. This improves the reliability of the light-emitting device.

[0203] 8B shows an example in which the common electrode 115 is embedded in the regions between the light-emitting devices (between the sidewalls 121) and in the recesses of the transistor-containing layer 101. FIG. 8C shows an example in which a void 134 is formed in the regions between the light-emitting devices (between the sidewalls 121) and in the recesses of the transistor-containing layer 101. Specifically, in FIG. 8C, the void 134 is surrounded by the transistor-containing layer 101, the sidewalls 121, and the common electrode 115.

[0204] As shown in Figures 7B and 8A, one or more layers constituting the EL layer may be formed after the sidewall 121 is provided. In other words, the first layer 113a, the second layer 113b, and the third layer 113c can each be considered to be part of the EL layer. Also, as shown in Figures 8B and 8C, after the sidewall 121 is provided, the common electrode 115 may be formed without forming any layers constituting the EL layer. In other words, the EL layer in the light-emitting device corresponds to the first layer 113a, the second layer 113b, and the third layer 113c.

[0205] Thereafter, a protective layer 131 is formed on the common electrode 115, and a protective layer 132 is formed on the protective layer 131. Furthermore, by using the resin layer 119, a substrate 120 is bonded onto the protective layer 132, whereby the display device 100 shown in FIG. 1B can be manufactured.

[0206] The materials and film formation methods that can be used for the protective layers 131 and 132 are as described above. Film formation methods for the protective layers 131 and 132 include vacuum deposition, sputtering, CVD, and ALD. The protective layers 131 and 132 may be films formed using different film formation methods. Furthermore, the protective layers 131 and 132 may each have a single-layer structure or a multilayer structure.

[0207] [Display Device Variation 1] 9A to 9C and 10A to 10C are cross-sectional views taken along the dashed dotted line X1-X2 in FIG. 1A.

[0208] The structures shown in FIGS. 9A to 9C and 10A are fabricated by forming the electron injection layer 114 and the common electrode 115 after forming the sidewalls 121, as shown in FIGS. 7B and 7C, respectively.

[0209] FIG. 7B shows an example in which the electron injection layer 114 is embedded in the regions between the light emitting devices (between the sidewalls 121) and in the recesses of the layer 101 including the transistor, but this is not limiting.

[0210] 9A, in the region between the light-emitting devices (between the sidewalls 121), the electron injection layer 114 may be provided along the sidewalls 121, and the common electrode 115 may be embedded. Since the sidewalls 121 are provided in the region between the light-emitting devices, even if the common electrode 115 is formed in that region, it is possible to prevent the light-emitting devices from shorting out.

[0211] Furthermore, as shown in FIG. 9B, in the region between the light-emitting devices (between the sidewalls 121), the electron injection layer 114 and the common electrode 115 may be provided along the sidewalls 121, and a protective layer 131 may be embedded.

[0212] 9C and 10A show examples in which voids 134 are formed in regions between the light-emitting devices (between the sidewalls 121) and in recesses in the transistor-containing layer 101. Specifically, in FIG. 9C, voids 134 are provided that are surrounded by the transistor-containing layer 101, the sidewalls 121, and the electron injection layer 114. In FIG. 10A, voids 134 exist between the electron injection layer 114 and the common electrode 115.

[0213] The structures shown in Figures 10B and 10C are each fabricated by forming the fourth electron transport layer 116, the electron injection layer 114, and the common electrode 115 after forming the sidewall 121, as shown in Figure 8A.

[0214] 10B, the common electrode 115 is embedded in the region between the light-emitting devices (between the sidewalls 121). The sidewalls 121 are provided in the region between the light-emitting devices, and the fourth electron transport layer 116 and the electron injection layer 114 are further provided along the sidewalls 121. Therefore, even if the common electrode 115 is formed in this region, it is possible to prevent the light-emitting devices from shorting out.

[0215] 10C shows an example in which voids 134 are formed in the regions between the light-emitting devices (between the sidewalls 121) and in the recesses of the transistor-containing layer 101. Specifically, in FIG. 10C, voids 134 exist between the electron injection layer 114 and the fourth electron transport layer 116.

[0216] As described above, a void may exist in a recess of the transistor-containing layer 101. Alternatively, a void may exist between any two of the sidewall 121, the fourth electron transport layer 116, the electron injection layer 114, the common electrode 115, and the protective layer 131. Note that, depending on the distance between adjacent light-emitting devices, the thickness of the electron injection layer 114, the thickness of the common electrode 115, and the thickness of the protective layer 131, such a void may not be formed. In this case, the space between adjacent light-emitting devices is filled with at least one of the electron injection layer 114, the common electrode 115, and the protective layer 131. Alternatively, an insulating material may be filled into the area that could become a void.

[0217] The void contains, for example, one or more selected from air, nitrogen, oxygen, carbon dioxide, and Group 18 elements (typically, helium, neon, argon, xenon, krypton, etc.). The void may also contain a gas used in forming the electron injection layer 114 or other films. For example, when the electron injection layer 114 is formed by vacuum deposition, the void may be in a reduced pressure atmosphere. When the void contains a gas, the gas can be identified by gas chromatography or the like.

[0218] Furthermore, when the refractive index of the void is lower than that of the electron injection layer 114, the common electrode 115, or the protective layer 131, light emitted from the first layer 113a, the second layer 113b, or the third layer 113c is reflected at the interface between the electron injection layer 114, the common electrode 115, or the protective layer 131 and the void. This prevents the light emitted from the first layer 113a, the second layer 113b, or the third layer 113c from entering an adjacent pixel (or subpixel). This prevents light of different colors from mixing, thereby improving the display quality of the display device.

[0219] Furthermore, an insulating material may be filled into the portion that could become the void 134. The insulating material may be an organic insulating material or an inorganic insulating material, or both. The insulating material may be at least one of a solid material, a gel material, and a liquid material.

[0220] Examples of organic insulating materials include acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyimideamide resin, polysiloxane resin, benzocyclobutene resin, phenol resin, etc. Also, various resins that can be used for the resin layer 119 may be used.

[0221] Examples of inorganic insulating materials include oxide insulating materials, nitride insulating materials, oxynitride insulating materials, and nitride oxide insulating materials. In addition, insulating materials that can be used for the protective layers 131 and 132 may also be used.

[0222] As described above, the shape of the layer formed after the sidewall 121 is formed can vary depending on the material, the film formation method, the film thickness, and the like, and is not particularly limited. The display device of one embodiment of the present invention has a structure in which short-circuiting of the light-emitting device is suppressed by including the sidewall 121. Therefore, the range of options for the material, the film formation method, and the film thickness of the layer formed after the sidewall 121 is formed can be expanded.

[0223] [Example 2 of manufacturing method of display device] Next, an example of a method for manufacturing a display device will be described with reference to Fig. 11 and Fig. 12. Fig. 11A to Fig. 11C show a cross-sectional view taken along dashed lines X1-X2 and Y1-Y2 in Fig. 1A side by side. Fig. 12 is similar to Fig. 11.

[0224] In this manufacturing method example 2, the step shown in Fig. 5C is followed by the steps shown in Fig. 11 and 12. Note that detailed descriptions of the same parts as in this manufacturing method example 1 may be omitted.

[0225] First, as shown in FIG. 11A, an insulating film 121B is formed to cover the first layer 113a, the second layer 113b, the third layer 113c, the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c.

[0226] The insulating film 121B can be formed using a material and method that are applicable to the insulating film 121A.

[0227] 11B, the insulating film 121B is processed to form side walls 122. The side walls 122 are provided so as to cover the side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c. This makes it possible to suppress damage to the first layer 113a, the second layer 113b, and the third layer 113c during the processing step of the conductive film 111.

[0228] 11C , the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c are used as hard masks to process the conductive film 111 to form pixel electrodes 111a, 111b, and 111c, and a conductive layer 123. Here, the sidewall 122 also serves as a hard mask, and the pixel electrodes 111a, 111b, and 111c, and the conductive layer 123 are also provided below the sidewall 122.

[0229] Next, as shown in FIG. 12A, an insulating film 121A is formed to cover the first layer 113a, the second layer 113b, the third layer 113c, the sidewall 122, the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c.

[0230] Next, as shown in Fig. 12B, the insulating film 121A is processed to form the sidewall 121. The sidewall 121 is provided so as to cover the side surfaces of the sidewall 122 and the pixel electrodes 111a, 111b, and 111c. This prevents a film (a film constituting the EL layer or a common electrode) to be formed later from coming into contact with the pixel electrodes 111a, 111b, and 111c, thereby preventing a short circuit in the light-emitting device. Note that the sidewall 121 may cover not only the side surfaces of the sidewall 122 but also the top surfaces.

[0231] Thereafter, the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c are removed, thereby exposing the first electron transport layer 184a on the pixel electrode 111a, the second electron transport layer 184b on the pixel electrode 111b, the third electron transport layer 184c on the pixel electrode 111c, and the conductive layer 123 at the connection portion 140.

[0232] 12C, the electron injection layer 114 is formed to cover the sidewall 121, the first layer 113a, the second layer 113b, and the third layer 113c. As shown in the cross-sectional view between Y1 and Y2, the end of the electron injection layer 114 on the connection portion 140 side is located inside the connection portion 140 and is not formed on the conductive layer 123.

[0233] Then, as shown in FIG. 12C, a common electrode 115 is formed on the electron injection layer 114 and the conductive layer 123.

[0234] Then, the protective layer 131 is formed over the common electrode 115, and the protective layer 132 is formed over the protective layer 131. Furthermore, the substrate 120 is attached to the protective layer 132 using the resin layer 119, whereby the display device of one embodiment of the present invention can be manufactured.

[0235] [Display Device Manufacturing Method Example 3] Next, an example of a method for manufacturing a display device will be described with reference to Fig. 13 and Fig. 14. Fig. 13A to Fig. 13C show a cross-sectional view taken along dashed lines X1-X2 and Y1-Y2 in Fig. 1A side by side. Fig. 14 is similar to Fig. 13.

[0236] In this manufacturing method example 3, the step shown in Fig. 3B is followed by the steps shown in Fig. 13 and 14. Note that detailed description of the same parts as in manufacturing method example 1 may be omitted.

[0237] In the example manufacturing method 1, as shown in FIG. 3C, the resist mask 190a used to form the first layer 113a is removed, and then the process proceeds to the step of forming the second layer 113b as shown in FIG. 4A. However, the process may proceed to the next step without removing the resist mask 190a.

[0238] That is, as shown in Figures 13A and 13B, after forming the first layer 113a, the second hole injection layer 181B, the second hole transport layer 182B, the second light-emitting layer 183B, the second electron transport layer 184B, the second sacrificial layer 118B, and the resist mask 190b may be formed while leaving the resist mask 190a.

[0239] Therefore, when the second layer 113b is formed, a stacked structure of the first sacrificial layer 118a and the resist mask 190a remains on the first layer 113a, and a stacked structure of the second sacrificial layer 118b and the resist mask 190b remains on the second layer 113b (see FIG. 13C). Then, with the resist masks 190a and 190b remaining, the process proceeds to the step of forming the third layer 113c.

[0240] 14A, when the third layer 113c is formed, a layered structure of the first sacrificial layer 118a and the resist mask 190a remains on the first layer 113a, and a layered structure of the second sacrificial layer 118b and the resist mask 190b remains on the second layer 113b. Furthermore, a layered structure of the third sacrificial layer 118c and the resist mask 190c remains on the third layer 113c. Furthermore, a layered structure of the third sacrificial layer 118c and the resist mask 190c remains in the region that will later become the connection portion 140.

[0241] Next, as shown in FIG. 14B, the conductive film 111 is processed using resist masks 190a, 190b, and 190c to form pixel electrodes 111a, 111b, and 111c and a conductive layer 123. Then, as shown in FIG.

[0242] The use of the resist masks 190a, 190b, and 190c is preferable because it makes it easier to process the conductive film 111 than using the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c as hard masks. For example, the range of options for processing the conductive film 111, materials for the sacrificial layers, and materials for the conductive films can be expanded.

[0243] [Display Device Variation 2] 15 to 18, examples of the configuration of a light-emitting device different from the above will be described.

[0244] 15A shows a schematic cross-sectional view of a display device 500. The display device 500 has a light emitting device 550R that emits red light, a light emitting device 550G that emits green light, and a light emitting device 550B that emits blue light.

[0245] The light-emitting device 550R has a configuration in which two light-emitting units (light-emitting unit 512R_1 and light-emitting unit 512R_2) are stacked between a pair of electrodes (electrode 501 and electrode 502) via an intermediate layer 531. Similarly, the light-emitting device 550G has light-emitting units 512G_1 and 512G_2, and the light-emitting device 550B has light-emitting units 512B_1 and 512B_2.

[0246] An electrode 501 functions as a pixel electrode and is provided for each light-emitting device, and an electrode 502 functions as a common electrode and is provided in common to a plurality of light-emitting devices.

[0247] The light-emitting unit 512R_1 includes a layer 521, a layer 522, a light-emitting layer 523R, a layer 524, etc. The light-emitting unit 512R_2 includes a layer 522, a light-emitting layer 523R, a layer 524, etc. The light-emitting device 550R includes a layer 525 between the light-emitting unit 512R_2 and the electrode 502. The layer 525 can also be considered as part of the light-emitting unit 512R_2.

[0248] The layer 521 includes, for example, a layer containing a substance with a high hole-injecting property (hole-injecting layer). The layer 522 includes, for example, a layer containing a substance with a high hole-transporting property (hole-transporting layer). The layer 524 includes, for example, a layer containing a substance with a high electron-transporting property (electron-transporting layer). The layer 525 includes, for example, a layer containing a substance with a high electron-injecting property (electron-injecting layer).

[0249] Alternatively, a structure in which the layer 521 has an electron-injecting layer, the layer 522 has an electron-transporting layer, the layer 524 has a hole-transporting layer, and the layer 525 has a hole-injecting layer may be used.

[0250] The layer 522, the light-emitting layer 523R, and the layer 524 may have the same configuration (material, film thickness, etc.) between the light-emitting unit 512R_1 and the light-emitting unit 512R_2, or may have different configurations.

[0251] 15A, the layer 521 and the layer 522 are shown separately, but this is not limiting. For example, when the layer 521 has a function as both a hole injection layer and a hole transport layer, or when the layer 521 has a function as both an electron injection layer and an electron transport layer, the layer 522 may be omitted.

[0252] Furthermore, the intermediate layer 531 has a function of injecting electrons into one of the light-emitting unit 512R_1 and the light-emitting unit 512R_2 and injecting holes into the other when a voltage is applied between the electrode 501 and the electrode 502. The intermediate layer 531 can also be called a charge generation layer.

[0253] For example, a material applicable to an electron injection layer, such as lithium, can be suitably used for the intermediate layer 531. For example, a material applicable to a hole injection layer can be suitably used for the intermediate layer. For example, a layer containing a hole transport material and an acceptor material (electron acceptor material) can be used for the intermediate layer. For example, a layer containing an electron transport material and a donor material can be used for the intermediate layer. By forming an intermediate layer having such a layer, an increase in driving voltage can be suppressed when light-emitting units are stacked.

[0254] Light-emitting layer 523R of light-emitting device 550R contains a light-emitting material that emits red light, light-emitting layer 523G of light-emitting device 550G contains a light-emitting material that emits green light, and light-emitting layer 523B of light-emitting device 550B contains a light-emitting material that emits blue light. Light-emitting device 550G and light-emitting device 550B have a configuration in which light-emitting layer 523R of light-emitting device 550R is replaced with light-emitting layer 523G and light-emitting layer 523B, respectively, and are otherwise similar in configuration to light-emitting device 550R.

[0255] The layers 521, 522, 524, and 525 may have the same configuration (material, film thickness, etc.) for each color light-emitting device, or may have different configurations.

[0256] A configuration in which multiple light-emitting units are connected in series via an intermediate layer 531, such as light-emitting device 550R, light-emitting device 550G, and light-emitting device 550B, is referred to herein as a tandem structure. On the other hand, a configuration having one light-emitting unit between a pair of electrodes is referred to as a single structure. Although the term "tandem structure" is used herein, the term is not limited thereto; for example, the tandem structure may be referred to as a stack structure. The tandem structure can provide a light-emitting device capable of emitting light with high brightness. Furthermore, the tandem structure can reduce the current required to achieve the same brightness compared to a single structure, thereby improving reliability.

[0257] Furthermore, a structure in which a separate light-emitting layer is formed for each light-emitting device, such as light-emitting device 550R, light-emitting device 550G, and light-emitting device 550B, is sometimes called an SBS (Side By Side) structure. The SBS structure allows the materials and configuration to be optimized for each light-emitting device, increasing the freedom in material and configuration selection and facilitating improvements in brightness and reliability.

[0258] The display device 500 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. As shown in FIG. 15A, the display device 500 has two light-emitting units formed in series, and therefore may be referred to as a two-tier tandem structure. In the two-tier tandem structure shown in FIG. 15A, a second light-emitting unit having a red light-emitting layer is stacked on a first light-emitting unit having a red light-emitting layer. Similarly, in the two-tier tandem structure shown in FIG. 15A, a second light-emitting unit having a green light-emitting layer is stacked on a first light-emitting unit having a green light-emitting layer, and a second light-emitting unit having a blue light-emitting layer is stacked on a first light-emitting unit having a blue light-emitting layer.

[0259] 15A, the light-emitting unit 512R_1, the intermediate layer 531, the light-emitting unit 512R_2, and the layer 525 can be formed as island-shaped layers. The light-emitting unit 512G_1, the intermediate layer 531, the light-emitting unit 512G_2, and the layer 525 can be formed as island-shaped layers. The light-emitting unit 512B_1, the intermediate layer 531, the light-emitting unit 512B_2, and the layer 525 can be formed as island-shaped layers. That is, the layer 113 shown in FIG. 15A corresponds to the first layer 113a, the second layer 113b, or the third layer 113c shown in FIG. 1B, etc.

[0260] 15B is a modified example of the display device 500 shown in FIG. 15A. The display device 500 shown in FIG. 15B is an example in which the layer 525 is provided in common among the light-emitting devices, similar to the electrode 502. In this case, the layer 525 can be called a common layer. By providing one or more common layers among the plurality of light-emitting devices in this way, the manufacturing process can be simplified, and therefore the manufacturing cost can be reduced.

[0261] In FIG. 15A, the light-emitting unit 512R_1, the intermediate layer 531, and the light-emitting unit 512R_2 can be formed as island-shaped layers. The light-emitting unit 512G_1, the intermediate layer 531, and the light-emitting unit 512G_2 can be formed as island-shaped layers. The light-emitting unit 512B_1, the intermediate layer 531, and the light-emitting unit 512B_2 can be formed as island-shaped layers. That is, the layer 113 shown in FIG. 15B corresponds to the first layer 113a, the second layer 113b, or the third layer 113c shown in FIG. 1B and the like. The layer 525 corresponds to the electron-injection layer 114 shown in FIG. 1B. In FIGS. 16 to 18, the layer corresponding to the first layer 113a, the second layer 113b, or the third layer 113c shown in FIG. 1B and the like is also referred to as the layer 113.

[0262] The display device 500 shown in FIG. 16A is an example in which three light-emitting units are stacked. In FIG. 16A, a light-emitting device 550R has a light-emitting unit 512R_3 stacked on a light-emitting unit 512R_2 with an intermediate layer 531 interposed therebetween. The light-emitting unit 512R_3 has a layer 522, a light-emitting layer 523R, a layer 524, and the like. The light-emitting unit 512R_3 can have a similar configuration to the light-emitting unit 512R_2. The same applies to the light-emitting unit 512G_3 included in the light-emitting device 550G and the light-emitting unit 512B_3 included in the light-emitting device 550B.

[0263] FIG. 16B shows an example in which n light-emitting units (n is an integer of 2 or more) are stacked.

[0264] In this way, by increasing the number of stacked light-emitting units, the luminance obtained from the light-emitting device with the same amount of current can be increased in proportion to the number of stacked light-emitting units.Furthermore, by increasing the number of stacked light-emitting units, the current required to obtain the same luminance can be reduced, and therefore the power consumption of the light-emitting device can be reduced in proportion to the number of stacked light-emitting units.

[0265] The display device 500 shown in FIG. 17A illustrates an example in which two adjacent light-emitting devices are spaced apart, and electrodes 502 are provided along the side surfaces of the light-emitting units and intermediate layer 531.

[0266] Here, if the intermediate layer 531 and the electrode 502 come into contact with each other, an electrical short circuit may occur. Therefore, it is preferable to insulate the intermediate layer 531 from the electrode 502.

[0267] 17A shows an example in which an insulating layer 541 is provided to cover the side surfaces of the electrode 501, each light-emitting unit, and the intermediate layer 531. The insulating layer 541 can be called a side wall, a side wall protective layer, a side wall insulating film, or the like. By providing the insulating layer 541, the intermediate layer 531 and the electrode 502 can be electrically insulated from each other.

[0268] The side surfaces of the light-emitting units and the intermediate layer 531 are preferably perpendicular or approximately perpendicular to the surface on which they are formed. For example, the angle between the surface on which they are formed and these side surfaces is preferably 60 degrees or more and 90 degrees or less.

[0269] 17B shows an example in which layer 525 and electrode 502 are provided along the side surfaces of the light-emitting unit and intermediate layer 531. Furthermore, a two-layer structure of insulating layers 541 and 542 is provided as a sidewall protective layer.

[0270] FIG. 18A is a modified example of FIG. 17B. FIG. 18B is an enlarged view of region 503 shown in FIG. 18A. The shapes of the end portions of insulating layer 542 differ between FIG. 18A and FIG. 17B. Furthermore, because the shapes of the end portions of insulating layer 542 are different and layer 525 and electrode 502 are formed along the shape of insulating layer 542, the shapes of layer 525 and electrode 502 are also different. FIG. 18A also differs from FIG. 17B in that the thickness of insulating layer 542 is thicker than that of insulating layer 541. The shape of the end portion of insulating layer 542 can be rounded as shown in FIG. 18B. For example, when forming insulating layer 542, if dry etching is used and the upper portion of insulating layer 542 is etched by anisotropic etching, the end portion of insulating layer 542 becomes rounded as shown in FIG. 18B. By rounding the end portion of insulating layer 542, the coverage of layer 525 and electrode 502 is improved, which is preferable. As shown in FIGS. 18A and 18B, by making the thickness of insulating layer 542 thicker than the thickness of insulating layer 541, it may be easier to make the end shape round.

[0271] The insulating layer 541 (and insulating layer 542) functioning as a sidewall protective layer can prevent an electrical short circuit between the electrode 502 and the intermediate layer 531. Furthermore, the insulating layer 541 (and insulating layer 542) covering the side surface of the electrode 501 can prevent an electrical short circuit between the electrode 501 and the electrode 502. This can prevent an electrical short circuit at the four corners of the light-emitting device.

[0272] The insulating layers 541 and 542 are preferably formed using an inorganic insulating film. For example, an oxide or nitride such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum oxynitride, or hafnium oxide can be used. Yttrium oxide, zirconium oxide, gallium oxide, tantalum oxide, magnesium oxide, lanthanum oxide, cerium oxide, neodymium oxide, or the like may also be used. Materials similar to those of the side walls 121 and 122 can also be used. The structure of the insulating layers 541 and 542 can also be applied to the side walls 121 and 122.

[0273] The insulating layers 541 and 542 can be formed by various film formation methods, such as sputtering, vapor deposition, CVD, and ALD. In particular, the ALD method causes less film formation damage to the layer on which it is formed, so it is preferable to form the insulating layer 541, which is formed directly on the light-emitting unit and the intermediate layer 531, by the ALD method. In this case, it is also preferable to form the insulating layer 542 by sputtering, as this can increase productivity.

[0274] For example, the insulating layer 541 can be an aluminum oxide film formed by an ALD method, and the insulating layer 542 can be a silicon nitride film formed by a sputtering method.

[0275] One or both of the insulating layers 541 and 542 preferably function as a barrier insulating film against at least one of water and oxygen. Alternatively, one or both of the insulating layers 541 and 542 preferably have a function of suppressing diffusion of at least one of water and oxygen. Alternatively, one or both of the insulating layers 541 and 542 preferably have a function of capturing or fixing (also referred to as gettering) at least one of water and oxygen.

[0276] In this specification and the like, a barrier insulating film refers to an insulating film having barrier properties. In addition, in this specification and the like, the barrier properties refer to a function of suppressing the diffusion of a corresponding substance (also referred to as low permeability), or a function of capturing or fixing (also referred to as gettering) a corresponding substance.

[0277] When one or both of the insulating layers 541 and 542 have the above-described barrier insulating film function or gettering function, the structure can suppress the intrusion of impurities (typically, water or oxygen) that can diffuse into each light-emitting device from the outside. With this structure, a display device with excellent reliability can be provided.

[0278] 18C, the insulating layer 541 and the insulating layer 542 functioning as the sidewall protective layer may not be provided. In FIG. 18C, the layer 525 is provided in contact with the side surfaces of the light-emitting units and the intermediate layer 531.

[0279] 15A , the light-emitting layer 523R of the light-emitting unit 512R_1 may include a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 may include a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 may include a fluorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 may include a fluorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 may include a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 may include a fluorescent material.

[0280] Alternatively, in the display device 500 shown in FIG. 15A, the light-emitting layer 523R of the light-emitting unit 512R_1 can have a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 can have a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 can have a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 can have a phosphorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 can have a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 can have a fluorescent material.

[0281] Note that the display device of one embodiment of the present invention may have a structure in which all light-emitting layers are formed using a fluorescent material or a structure in which all light-emitting layers are formed using a phosphorescent material.

[0282] 15A , the light-emitting layer 523R of the light-emitting unit 512R_1 may be made of a phosphorescent material and the light-emitting layer 523R of the light-emitting unit 512R_2 may be made of a fluorescent material, or the light-emitting layer 523R of the light-emitting unit 512R_1 may be made of a fluorescent material and the light-emitting layer 523R of the light-emitting unit 512R_2 may be made of a phosphorescent material, that is, the light-emitting layers of the first and second stages may be made of different materials. Note that, although the description here has been made explicitly about the light-emitting units 512R_1 and 512R_2, the same configurations can also be applied to the light-emitting units 512G_1 and 512G_2, and the light-emitting units 512B_1 and 512B_2.

[0283] As described above, in the manufacturing method of the display device of this embodiment, the island-shaped EL layer is formed by forming the EL layer on the entire surface and then processing it, rather than by using a fine metal mask, so that the island-shaped EL layer can be formed with a uniform thickness, and a high-definition display device or a display device with a high aperture ratio can be realized.

[0284] The first, second, and third layers that make up the light-emitting device for each color are formed in separate processes. This allows each EL layer to be fabricated with a configuration (material, film thickness, etc.) that is suitable for the light-emitting device for that color. This allows for the fabrication of light-emitting devices with excellent characteristics.

[0285] A display device according to one embodiment of the present invention has sidewalls covering the respective side surfaces of the pixel electrode, the light-emitting layer, and the carrier transport layer. In a manufacturing process of the display device, the EL layer is processed in a state in which the light-emitting layer and the carrier transport layer are stacked. Therefore, the display device has a structure in which damage to the light-emitting layer is reduced. Furthermore, the sidewalls prevent the pixel electrode from contacting the carrier injection layer or the common electrode, thereby preventing a short circuit of the light-emitting device.

[0286] This embodiment mode can be combined with other embodiment modes as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0287] (Embodiment 2) In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0288] The display device of the present embodiment can be a high-definition display device, and can therefore be used as a display unit for information terminals (wearable devices) such as wristwatches and bracelets, as well as for wearable devices that can be worn on the head, such as VR devices such as head-mounted displays and AR devices such as glasses.

[0289] [Display module] 19A shows a perspective view of display module 280. Display module 280 has display device 100A and FPC 290. Note that the display device included in display module 280 is not limited to display device 100A, and may be display device 100B or display device 100C, which will be described later.

[0290] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display unit 281. The display unit 281 is a region that displays an image in the display module 280, and is a region where light from each pixel provided in a pixel unit 284 (described later) can be viewed.

[0291] 19B is a perspective view showing a schematic configuration of the substrate 291 side. 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 on the substrate 291. A terminal section 285 for connecting to an FPC 290 is provided in a 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 consisting of a plurality of wirings.

[0292] The pixel section 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of FIG. 19B. The pixel 284a has light-emitting devices 130a, 130b, and 130c that emit light of different colors. In this embodiment, an example will be described in which the pixel 284a is composed of a light-emitting device 130a that emits red light, a light-emitting device 130b that emits green light, and a light-emitting device 130c that emits blue light. The plurality of light-emitting devices can be arranged in a stripe array as shown in FIG. 19B. Various light-emitting device arrangement methods, such as a delta array or a pentile array, can also be applied.

[0293] Here, when a pixel of a display device has three types of subpixels having light-emitting devices that emit light of different colors, the three subpixels include subpixels of three colors of R, G, and B, or subpixels of three colors of yellow (Y), cyan (C), and magenta (M), etc. When a pixel of a display device has four subpixels, the four subpixels include subpixels of four colors of R, G, B, and white (W), or subpixels of four colors of R, G, B, and Y, etc.

[0294] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0295] One pixel circuit 283a is a circuit that controls the light emission of three light-emitting devices included in one pixel 284a. One pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting device. For example, the pixel circuit 283a may be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitance element for each light-emitting device. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain. This realizes an active matrix display device.

[0296] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Furthermore, either a top-gate transistor or a bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0297] The crystallinity of the semiconductor material used for the transistor is not particularly limited, and any of an amorphous semiconductor, a single-crystal semiconductor, and a semiconductor having crystallinity other than single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single-crystal semiconductor or a crystalline semiconductor is preferable because it can suppress deterioration of the transistor characteristics.

[0298] The semiconductor layer of the transistor preferably contains metal oxide (also referred to as an oxide semiconductor). That is, the display device of this embodiment preferably uses a transistor using metal oxide in a channel formation region (hereinafter referred to as an OS transistor). Alternatively, the semiconductor layer of the transistor preferably contains silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystal silicon).

[0299] The semiconductor layer preferably contains, for example, indium, M (wherein M is one or more elements 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 elements selected from aluminum, gallium, yttrium, and tin.

[0300] 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.

[0301] When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. Examples of atomic ratios of metal elements in such In-M-Zn oxides include compositions in which In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:1:1.2 or thereabouts, In:M:Zn=2:1:3 or thereabouts, In:M:Zn=3:1:2 or thereabouts, In:M:Zn=4:2:3 or thereabouts, In:M:Zn=4:2:4.1 or thereabouts, In:M:Zn=5:1:3 or thereabouts, In:M:Zn=5:1:6 or thereabouts, In:M:Zn=5:1:7 or thereabouts, In:M:Zn=5:1:8 or thereabouts, In:M:Zn=6:1:6 or thereabouts, and In:M:Zn=5:2:5 or thereabouts, etc. Note that "nearby compositions" includes a range of ±30% of the desired atomic ratio.

[0302] For example, when describing a composition with an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, this includes a case where, when In is taken as 4, Ga is 1 to 3 and Zn is 2 to 4. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, this includes a case where, when In is taken as 5, Ga is greater than 0.1 and 2 or less and Zn is 5 to 7 or less. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, this includes a case where, when In is taken as 1, Ga is greater than 0.1 and 2 or less and Zn is greater than 0.1 and 2 or less.

[0303] The transistors included in the circuit portion 282 and the transistors included in the pixel circuit portion 283 may have the same structure or different structures. The transistors included in the circuit portion 282 may all have the same structure or may have two or more types. Similarly, the transistors included in the pixel circuit portion 283 may all have the same structure or may have two or more types.

[0304] The circuit portion 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like.

[0305] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit section 282. An IC (integrated circuit) may be mounted on the FPC 290.

[0306] The display module 280 can be configured to be provided below the pixel unit 284 so as to overlap one or both of the pixel circuit unit 283 and the circuit unit 282, thereby enabling the aperture ratio (effective display area ratio) of the display unit 281 to be extremely high. For example, the aperture ratio of the display unit 281 can be set to 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. Furthermore, the pixels 284a can be arranged at an extremely high density, enabling the resolution of the display unit 281 to be extremely high. For example, it is preferable that the pixels 284a are arranged in the display unit 281 at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20000 ppi or less, or 30000 ppi or less.

[0307] Such a display module 280 has extremely high resolution and can therefore be suitably used in VR devices such as head-mounted displays or eyeglass-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display unit 281, so that even if the display unit is enlarged with the lenses, the 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 having relatively small display units. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0308] [Display device 100A] The display device 100A shown in FIG. 20 includes a substrate 301, light emitting devices 130a, 130b, and 130c, a capacitor 240, and a transistor 310.

[0309] 19A and 19B. The stacked structure from the substrate 301 to the insulating layer 255 corresponds to the layer 101 including the transistor in the first embodiment.

[0310] The transistor 310 has a channel formation region in a substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part 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 in which the substrate 301 is doped with impurities and functions as either a source or a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0311] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0312] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided on the insulating layer 261 .

[0313] Capacitor 240 has conductive layer 241, conductive layer 245, and insulating layer 243 positioned therebetween. Conductive layer 241 functions as one electrode of capacitor 240, conductive layer 245 functions as the other electrode of capacitor 240, and insulating layer 243 functions as a dielectric of capacitor 240.

[0314] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain of the transistor 310 by a plug 271 buried 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 with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0315] An insulating layer 255 is provided to cover the capacitor 240, and light-emitting devices 130a, 130b, 130c, etc. are provided on the insulating layer 255. In this embodiment, an example is shown in which the light-emitting devices 130a, 130b, and 130c have the same stacked structure as the stacked structure shown in FIG. 1B. In addition, a protective layer 131 is provided on each of the light-emitting devices 130a, 130b, and 130c. A protective layer 132 is provided on the protective layer 131, and a substrate 120 is bonded to the protective layer 132 by a resin layer 119. For details of the components from the light-emitting devices to the substrate 120, refer to Embodiment 1. The substrate 120 corresponds to the substrate 292 in FIG. 19A.

[0316] The pixel electrode of the light-emitting device is electrically connected to one of the source or drain of transistor 310 by plug 256 embedded in insulating layer 255, conductive layer 241 embedded in insulating layer 254, and plug 271 embedded in insulating layer 261.

[0317] [Display device 100B] 21 differs from the display device 100A mainly in the configuration of the transistors, and a description of the same parts as those of the display device 100A may be omitted.

[0318] The transistor 320 is a transistor (OS transistor) in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

[0319] The transistor 320 includes 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 .

[0320] 19A and 19B. The stacked structure from the substrate 331 to the insulating layer 255 corresponds to the layer 101 including the transistor in Embodiment 1. The substrate 331 can be an insulating substrate or a semiconductor substrate.

[0321] An insulating layer 332 is provided over a 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 being released from the semiconductor layer 321 toward the insulating layer 332. The insulating layer 332 can be, for example, a film through which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0322] A conductive layer 327 is provided over the insulating layer 332, and an insulating layer 326 is provided to cover the conductive layer 327. The conductive layer 327 functions as a first gate electrode of the transistor 320, and part of the insulating layer 326 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a portion of the insulating layer 326 that is in contact with the semiconductor layer 321. The top surface of the insulating layer 326 is preferably planarized.

[0323] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide (also referred to as an oxide semiconductor) film having semiconductor properties. Materials that can be suitably used for the semiconductor layer 321 will be described in detail later.

[0324] A pair of conductive layers 325 is provided over and in contact with the semiconductor layer 321 and functions as a source electrode and a drain electrode.

[0325] An insulating layer 328 is provided to cover top surfaces and side surfaces of the pair of conductive layers 325 and side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided over the insulating layer 328. The insulating layer 328 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 264 or the like to the semiconductor layer 321 and prevents oxygen from being released from the semiconductor layer 321. The insulating layer 328 can be an insulating film similar to the insulating layer 332.

[0326] An opening reaching the semiconductor layer 321 is provided in the insulating layer 328 and the insulating layer 264. An insulating layer 323 and a conductive layer 324 are buried inside the opening and are in contact with the side surfaces of the insulating layer 264, the insulating layer 328, and the conductive layer 325 and the top 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.

[0327] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0328] The insulating layer 264 and the insulating layer 265 function as interlayer insulating layers. The insulating layer 329 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 265 or the like to the transistor 320. The insulating layer 329 can be formed using an insulating film similar to the insulating layer 328 and the insulating layer 332.

[0329] A plug 274 electrically connected to one of the pair of conductive layers 325 is provided to be embedded in the insulating layer 265, the insulating layer 329, and the insulating layer 264. Here, the plug 274 preferably includes a conductive layer 274a covering the side surfaces of the openings in the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328 and part of the top surface of the conductive layer 325, and a conductive layer 274b in contact with the top surface of the conductive layer 274a. In this case, the conductive layer 274a is preferably made of a conductive material through which hydrogen and oxygen do not easily diffuse.

[0330] Additionally, the layer 101 including the transistor may include various inorganic insulating films. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. Also, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may also be used. Two or more of the above insulating films may be stacked.

[0331] The configuration of the display device 100B from the insulating layer 254 to the substrate 120 is the same as that of the display device 100A.

[0332] [Display device 100C] 22 has a stacked structure of a transistor 310 having a channel formed in a substrate 301 and a transistor 320 having a channel formed in a semiconductor layer containing a metal oxide. Note that descriptions of parts similar to those of the display devices 100A and 100B may be omitted.

[0333] An insulating layer 261 is provided to cover the transistor 310, and a conductive layer 251 is provided over the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided over the insulating layer 262. The conductive layers 251 and 252 each function as wirings. An insulating layer 263 and an insulating layer 332 are provided to cover the conductive layer 252, and a transistor 320 is provided over the insulating layer 332. An insulating layer 265 is provided to cover the transistor 320, and a capacitor 240 is provided over the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0334] The transistor 320 can be used as a transistor included in a pixel circuit. The transistor 310 can be used as a transistor included in a pixel circuit or a driver circuit (gate line driver circuit, source line driver circuit) for driving the pixel circuit. The transistors 310 and 320 can be used as transistors included in various circuits such as an arithmetic circuit or a memory circuit.

[0335] By using this configuration, not only pixel circuits but also driving circuits etc. can be formed directly below the light-emitting device, making it possible to make the display device smaller than when driving circuits are provided around the periphery of the display area.

[0336] This embodiment mode can be combined with other embodiment modes as appropriate.

[0337] (Embodiment 3) In this embodiment, a light-emitting device that can be used for a display device of one embodiment of the present invention will be described.

[0338] 23A has an electrode 772, an EL layer 786, and an electrode 788. One of the electrodes 772 and 788 functions as an anode, and the other functions as a cathode. One of the electrodes 772 and 788 functions as a pixel electrode, and the other functions as a common electrode. Preferably, the electrode from which light is extracted, of the electrodes 772 and 788, is transparent to visible light, and the other electrode reflects visible light.

[0339] 23A, the EL layer 786 of the light-emitting device can be composed of multiple layers such as a layer 4420, a light-emitting layer 4411, and a layer 4430. The layer 4420 can have, for example, a layer containing a substance with high electron-injecting properties (electron-injecting layer) and a layer containing a substance with high electron-transporting properties (electron-transporting layer). The light-emitting layer 4411 contains, for example, a light-emitting compound. The layer 4430 can have, for example, a layer containing a substance with high hole-injecting properties (hole-injecting layer) and a layer containing a substance with high hole-transporting properties (hole-transporting layer).

[0340] A structure including the layer 4420, the light-emitting layer 4411, and the layer 4430 provided between a pair of electrodes can function as a single light-emitting unit, and the structure of FIG. 23A is referred to as a single structure in this specification.

[0341] 23B shows a modified example of the EL layer 786 of the light-emitting device shown in Fig. 23A. Specifically, the light-emitting device shown in Fig. 23B has a layer 4431 on an electrode 772, a layer 4432 on the layer 4431, a light-emitting layer 4411 on the layer 4432, a layer 4421 on the light-emitting layer 4411, a layer 4422 on the layer 4421, and an electrode 788 on the layer 4422. For example, when the electrode 772 is an anode and the electrode 788 is a cathode, the layer 4431 functions as a hole injection layer, the layer 4432 functions as a hole transport layer, the layer 4421 functions as an electron transport layer, and the layer 4422 functions as an electron injection layer. Alternatively, when the electrode 772 is a cathode and the electrode 788 is an anode, the layer 4431 functions as an electron injection layer, the layer 4432 functions as an electron transport layer, the layer 4421 functions as a hole transport layer, and the layer 4422 functions as a hole injection layer. With such a layer structure, carriers can be efficiently injected into the light-emitting layer 4411, and the efficiency of carrier recombination in the light-emitting layer 4411 can be increased.

[0342] As shown in FIG. 23C, a configuration in which a plurality of light-emitting layers (light-emitting layers 4411, 4412, 4413) are provided between layer 4420 and layer 4430 is also a variation of the single structure.

[0343] 23D, a configuration in which multiple light-emitting units (EL layers 786a, 786b) are connected in series via an intermediate layer 4440 (also referred to as a charge generation layer) is referred to as a tandem structure in this specification. This is not limiting, and the tandem structure may also be referred to as a stack structure, for example. The tandem structure allows for a light-emitting device capable of emitting light with high brightness.

[0344] 23C and 23D, as shown in FIG. 23B, each of the layer 4420 and the layer 4430 can have a laminated structure made up of two or more layers.

[0345] The light-emitting device can emit light of red, green, blue, cyan, magenta, yellow, or white, depending on the material of the EL layer 786. The color purity can be further improved by providing the light-emitting device with a microcavity structure.

[0346] A light-emitting device that emits white light preferably has a configuration in which the light-emitting layer contains two or more types of light-emitting materials. To achieve white light emission, light-emitting materials can be selected so that the emissions of the two or more light-emitting materials have a complementary color relationship. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary, a light-emitting device that emits white light as a whole can be obtained. The same applies to light-emitting devices having three or more light-emitting layers. For example, if the emission colors of the light-emitting layers 4411, 4412, and 4413 shown in Figure 23C are complementary, a single-structure white light-emitting device can be realized.

[0347] The light-emitting layer preferably contains two or more light-emitting materials that emit light of R (red), G (green), B (blue), Y (yellow), O (orange), etc. Alternatively, it is preferable that the light-emitting layer contains two or more light-emitting materials, and the light emitted by each of the light-emitting materials contains spectral components of two or more colors of R, G, and B.

[0348] This embodiment mode can be combined with other embodiment modes as appropriate.

[0349] (Fourth embodiment) In this embodiment, a metal oxide (also referred to as an oxide semiconductor) that can be used for the OS transistor described in the above embodiment will be described.

[0350] The metal oxide preferably contains at least indium or zinc. It is particularly preferable that it contains indium and zinc. It is also preferable that it contains aluminum, gallium, yttrium, tin, or the like in addition to these. It may also contain one or more elements selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, and the like.

[0351] Furthermore, the metal oxide can be formed by a sputtering method, a chemical vapor deposition (CVD) method such as a metal organic chemical vapor deposition (MOCVD) method, or an atomic layer deposition (ALD) method.

[0352] <Classification of crystal structures> Examples of the crystalline structure of oxide semiconductors include amorphous (including completely amorphous), c-axis-aligned crystalline (CAAC), nanocrystalline (nc), cloud-aligned composite (CAC), single crystal, and polycrystal.

[0353] The crystalline structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectra. For example, it can be evaluated using XRD spectra obtained by GIXD (Grazing-Incidence XRD) measurements. The GIXD method is also called the thin film method or the Seemann-Bohlin method.

[0354] For example, for a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, for an IGZO film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical peak shape of the XRD spectrum clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0355] The crystalline structure of a film or substrate can also be evaluated by the diffraction pattern (also called the nanobeam electron diffraction pattern) observed using nanobeam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, confirming that the quartz glass is in an amorphous state. Furthermore, a spot-like pattern is observed in the diffraction pattern of an IGZO film deposited at room temperature, rather than a halo. For this reason, it is estimated that an IGZO film deposited at room temperature is neither crystalline nor amorphous, but is in an intermediate state, and it cannot be concluded that it is in an amorphous state.

[0356] <<Oxide semiconductor structure>> Note that oxide semiconductors may be classified differently from the above when focusing on their structures. For example, oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0357] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0358] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, each with its c-axis aligned in a specific direction. The specific direction can be 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 the atomic arrangement is considered as a lattice arrangement, a crystalline region can also be a region with a uniform lattice arrangement. Furthermore, CAAC-OS has a region where multiple crystalline regions are connected in the ab-plane direction, and the region may have distortion. Note that distortion refers to a location where the lattice arrangement changes between a region with a uniform lattice arrangement and a region with a different uniform lattice arrangement in the region where multiple crystalline regions are connected. In other words, CAAC-OS is an oxide semiconductor with a c-axis aligned but no clear orientation in the ab-plane direction.

[0359] Each of the multiple crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of one minute crystal, the maximum diameter of the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of the crystalline region may be several tens of nm.

[0360] In an In-M-Zn oxide (wherein M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), the CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium (In) and oxygen (hereinafter referred to as an In layer) and a layer containing M, zinc (Zn), and oxygen (hereinafter referred to as an (M, Zn) layer) are stacked. Note that indium and the element M are mutually substituted. Therefore, the (M, Zn) layer may contain indium. The In layer may contain M. The In layer may contain Zn. The layered structure is observed as a lattice image in a high-resolution transmission electron microscope (TEM) image, for example.

[0361] When the CAAC-OS film is subjected to structural analysis using, for example, an XRD apparatus, a peak indicating c-axis orientation is detected at or near 2θ=31° in out-of-plane XRD measurement using θ / 2θ scan. Note that the position of the peak indicating c-axis orientation (2θ value) may vary depending on the type and composition of the metallic elements constituting the CAAC-OS.

[0362] For example, in the electron diffraction pattern of a CAAC-OS film, multiple bright spots are observed, and the spots are observed at positions that are point-symmetric with respect to the spot of the incident electron beam that has passed through the sample (also called the direct spot).

[0363] When the crystalline region is observed from the specific direction, the lattice arrangement within the crystalline region is basically a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the distortion may have a pentagonal, heptagonal, or other lattice arrangement. In the CAAC-OS, no clear grain boundaries are observed even near the distortion. This indicates that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is thought to be because the CAAC-OS can tolerate distortion due to the lack of close-packed oxygen atom arrangement in the ab-plane direction and the change in interatomic bond distance caused by metal atom substitution.

[0364] A crystal structure with clear grain boundaries is called polycrystalline. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in the on-state current and field-effect mobility of a transistor. Therefore, CAAC-OS, which lacks clear grain boundaries, is one of the crystalline oxides with a crystal structure suitable for use in the semiconductor layer of a transistor. Zn is preferred for use in CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are suitable because they can suppress the generation of grain boundaries more effectively than In oxide.

[0365] CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to crystal grain boundaries. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by impurities or defects, the CAAC-OS can be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Therefore, oxide semiconductors with CAAC-OS have stable physical properties. Therefore, oxide semiconductors with CAAC-OS are heat-resistant and highly reliable. Furthermore, the CAAC-OS is stable even under high temperatures (so-called thermal budgets) during the manufacturing process. Therefore, using a CAAC-OS for an OS transistor can increase the flexibility of the manufacturing process.

[0366] [nc-OS] The nc-OS has periodic atomic arrangement in a microscopic region (e.g., a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has microcrystalline structures. The size of the microcrystalline structures is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore these microcrystalline structures are also called nanocrystalline structures. Furthermore, the nc-OS exhibits no regularity in the crystal orientation between different nanocrystalline structures. Therefore, the entire film lacks orientation. Therefore, depending on the analytical method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor. For example, when a structural analysis of an nc-OS film is performed using an XRD apparatus, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Furthermore, when an nc-OS film is subjected to electron diffraction (also known as selected-area electron diffraction) using an electron beam with a probe diameter larger than that of nanocrystalline structures (e.g., 50 nm or larger), a halo-like diffraction 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 nanocrystals (for example, 1 nm to 30 nm), an electron diffraction pattern can be obtained in which multiple spots are observed within a ring-shaped region centered on the direct spot.

[0367] [a-like OS] The a-like OS is an oxide semiconductor having a structure between the nc-OS and the amorphous oxide semiconductor. The a-like OS has a pore or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS. Furthermore, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and CAAC-OS.

[0368] <<Oxide semiconductor structure>> Next, the above-mentioned CAC-OS will be described in detail, which relates to the material composition.

[0369] [CAC-OS] CAC-OS is a material structure in which elements constituting a metal oxide are unevenly distributed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or a similar size range. Hereinafter, a metal oxide in which one or more metal elements are unevenly distributed and the regions containing the metal elements are mixed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or a similar size range, is also referred to as a mosaic or patch state.

[0370] Furthermore, CAC-OS has a mosaic structure in which the material is separated into first and second regions, and the first regions are distributed throughout the film (hereinafter also referred to as a cloud structure). That is, CAC-OS is a composite metal oxide having a structure in which the first and second regions are mixed.

[0371] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In-Ga-Zn oxide are represented as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in the In-Ga-Zn oxide, the first region is a region where [In] is larger than [In] in the CAC-OS composition. The second region is a region where [Ga] is larger than [Ga] in the CAC-OS composition. Alternatively, for example, the first region is a region where [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. The second region is a region where [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

[0372] Specifically, the first region is a region whose main component is indium oxide, indium zinc oxide, or the like. The second region is a region whose main component is gallium oxide, gallium zinc oxide, or the like. In other words, the first region can be rephrased as a region whose main component is In. The second region can be rephrased as a region whose main component is Ga.

[0373] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0374] In addition, CAC-OS in In-Ga-Zn oxide refers to a material structure containing In, Ga, Zn, and O, in which some regions primarily composed of Ga and other regions primarily composed of In are randomly arranged in a mosaic pattern. Therefore, it is presumed that CAC-OS has a structure in which metal elements are distributed nonuniformly.

[0375] The CAC-OS can be formed, for example, by a sputtering method without heating the substrate. When the CAC-OS is formed by a sputtering method, one or more of an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. The lower the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition, the better. For example, the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition is preferably 0% or more and less than 30%, and more preferably 0% or more and 10% or less.

[0376] Furthermore, for example, in the case of CAC-OS in an In-Ga-Zn oxide, EDX mapping obtained using EDX (Energy Dispersive X-ray spectroscopy) confirms that the CAC-OS has a structure in which a region containing In as a main component (first region) and a region containing Ga as a main component (second region) are unevenly distributed and mixed.

[0377] Here, the first region has higher conductivity than the second region. That is, the flow of carriers through the first region causes the metal oxide to exhibit conductivity. Therefore, the first region is distributed in a cloud-like manner in the metal oxide, thereby achieving a high field-effect mobility (μ).

[0378] On the other hand, the second region has higher insulating properties than the first region. That is, the second region is distributed in the metal oxide, thereby suppressing leakage current.

[0379] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region act complementarily, thereby providing the CAC-OS with a switching function (the ability to turn on / off). In other words, CAC-OS has a conductive function in part of the material and an insulating function in part of the material, and the material as a whole functions as a semiconductor. By separating the conductive function from 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 behavior can be achieved.

[0380] Furthermore, a transistor using CAC-OS has high reliability, making it ideal for various semiconductor devices such as display devices.

[0381] Oxide semiconductors have a variety of structures, each with different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, a CAC-OS, an nc-OS, and a CAAC-OS.

[0382] <Transistors containing oxide semiconductors> Next, a case where the oxide semiconductor is used in a transistor will be described.

[0383] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0384] For the transistor, an oxide semiconductor with a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 Less than 1 × 10 15 cm -3 or less, more preferably 1 × 10 13 cm -3Less than or equal to 1×10 11 cm -3 or less, more preferably 1 × 10 10 cm -3 Less than 1 x 10 -9 cm -3 That is all. Note that in order to reduce the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification and the like, a semiconductor having a low impurity concentration and a low density of defect states is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Note that an oxide semiconductor having a low carrier concentration may also be referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor.

[0385] Furthermore, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore the density of trap states may also be low.

[0386] Furthermore, charges trapped in the trap states of an oxide semiconductor take a long time to dissipate and may behave like fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0387] Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in the adjacent film. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon.

[0388] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0389] When an oxide semiconductor contains silicon or carbon, which is one of the Group 14 elements, defect levels are formed in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are calculated to be 2×10 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0390] Furthermore, when an oxide semiconductor contains an alkali metal or alkaline earth metal, defect levels may be formed and carriers may be generated. Therefore, a transistor using an oxide semiconductor containing an alkali metal or alkaline earth metal is likely to have normally-on characteristics. Therefore, when the concentration of the alkali metal or alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 18 atoms / cm 3 Less than or equal to 2 x 10 16 atoms / cm 3 Do the following:

[0391] Furthermore, when nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor tends to have normally-on characteristics. Alternatively, when nitrogen is contained in an oxide semiconductor, trap states may be formed. As a result, the electrical characteristics of the transistor may become unstable. For this reason, the nitrogen concentration in the oxide semiconductor obtained by SIMS is set to 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than or equal to 1×10 18 atoms / cm 3 Less than 5 × 10, more preferably 17 atoms / cm 3 Do the following:

[0392] Furthermore, hydrogen contained in an oxide semiconductor may react with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. When hydrogen enters the oxygen vacancy, electrons serving as carriers may be generated. Furthermore, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons serving as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. For this reason, it is preferable to reduce the amount of hydrogen in the oxide semiconductor as much as possible. Specifically, the hydrogen concentration in an oxide semiconductor measured by SIMS is 1×10 20 atoms / cm 3 Less than 1 x 10 19 atoms / cm 3 less than 5 × 10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 Make it less than.

[0393] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0394] This embodiment mode can be combined with other embodiment modes as appropriate.

[0395] (Embodiment 5) In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS.

[0396] The electronic devices of this embodiment include the display device of one embodiment of the present invention in their display portions. The display device of one embodiment of the present invention can easily achieve high definition and high resolution. Therefore, the display device of one embodiment of the present invention can be used in the display portions of various electronic devices.

[0397] Examples of electronic devices include electronic devices with relatively large screens such as television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound playback devices.

[0398] In particular, the display device of one embodiment of the present invention can have high resolution and can therefore be suitably used in electronic devices having a relatively small display area. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), and head-mounted wearable devices such as VR devices (head-mounted displays), AR glasses-type devices, and MR glasses-type devices.

[0399] The display device of one embodiment of the present invention preferably has an extremely high resolution such as HD (1280 × 720 pixels), FHD (1920 × 1080 pixels), WQHD (2560 × 1440 pixels), WQXGA (2560 × 1600 pixels), 4K (3840 × 2160 pixels), or 8K (7680 × 4320 pixels). A resolution of 4K, 8K, or higher is particularly preferable. Furthermore, the pixel density (resolution) of the display device of one embodiment of the present invention is preferably 100 ppi or higher, preferably 300 ppi or higher, more preferably 500 ppi or higher, more preferably 1000 ppi or higher, more preferably 2000 ppi or higher, more preferably 3000 ppi or higher, more preferably 5000 ppi or higher, and even more preferably 7000 ppi or higher. By using a display device having either or both of high resolution and high definition, it is possible to further enhance the sense of realism and depth in electronic devices for personal use such as portable or home use. Furthermore, the screen ratio (aspect ratio) of the display device of one embodiment of the present invention is not particularly limited. For example, the display device can support various screen ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0400] The electronic device of this embodiment may have a sensor (including a function to measure force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0401] The electronic device of the present embodiment can have various functions, such as a function 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, time, etc., a function to execute various software (programs), a wireless communication function, a function to read out programs or data recorded on a recording medium, etc.

[0402] 24A, 24B, 25A, and 25B, an example of a wearable device that can be worn on the head will be described. These wearable devices have one or both of a function to display AR content and a function to display VR content. Note that these wearable devices may also have a function to display SR or MR content in addition to AR and VR. By having an electronic device have the function to display content such as AR, VR, SR, and MR, it is possible to enhance the user's sense of immersion.

[0403] Electronic device 700A shown in FIG. 24A and electronic device 700B shown in FIG. 24B each have 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.

[0404] The display device of one embodiment of the present invention can be applied to the display panel 751. Therefore, the electronic device can display images with extremely high resolution.

[0405] Electronic device 700A and electronic device 700B can each project an image displayed on display panel 751 onto display area 756 of optical member 753. Because optical member 753 is translucent, the user can see the image displayed in the display area superimposed on a transmitted image visually recognized through optical member 753. Therefore, electronic device 700A and electronic device 700B are each electronic devices capable of AR display.

[0406] Electronic device 700A and electronic device 700B may be provided with a camera capable of capturing an image in front of them as an imaging unit. Furthermore, electronic device 700A and electronic device 700B may each be provided with an acceleration sensor such as a gyro sensor, thereby detecting the orientation of the user's head and displaying an image corresponding to that orientation in display area 756.

[0407] The communication unit has a wireless communication device, and can supply a video signal, etc. Instead of or in addition to the wireless communication device, a connector to which a cable through which a video signal and a power supply potential are supplied may be provided.

[0408] Furthermore, the electronic device 700A and the electronic device 700B are provided with batteries, which can be charged wirelessly and / or by wire.

[0409] The housing 721 may be provided with a touch sensor module. The touch sensor module has a function of detecting a touch on the outer surface of the housing 721. The touch sensor module can detect a tap operation or a slide operation by the user and perform various processes. For example, a tap operation can perform a process such as pausing or resuming a video, and a slide operation can perform a process such as fast-forwarding or fast-rewinding. Furthermore, providing a touch sensor module on each of the two housings 721 can expand the range of operations.

[0410] Various touch sensors can be used as the touch sensor module. For example, various types of touch sensors can be used, such as a capacitance type, a resistive film type, an infrared type, an electromagnetic induction type, a surface acoustic wave type, and an optical type. In particular, it is preferable to use a capacitance type or an optical type sensor in the touch sensor module.

[0411] When an optical touch sensor is used, a photoelectric conversion device (also called a photoelectric conversion element) can be used as a light receiving device (also called a light receiving element). The active layer of the photoelectric conversion device can be made of either or both of an inorganic semiconductor and an organic semiconductor.

[0412] The electronic device 800A shown in FIG. 25A and the electronic device 800B shown in FIG. 25B each have 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.

[0413] The display device of one embodiment of the present invention can be applied to the display portion 820. Therefore, an electronic device capable of displaying images with extremely high resolution can be provided, which allows a user to feel a high sense of immersion.

[0414] Display unit 820 is provided inside housing 821 at a position that can be viewed through lens 832. Also, by displaying different images on the pair of display units 820, it is possible to perform a three-dimensional display using parallax.

[0415] Electronic device 800A and electronic device 800B can each be said to be electronic devices for VR. A user wearing electronic device 800A or electronic device 800B can view an image displayed on display unit 820 through lens 832.

[0416] It is preferable that electronic device 800A and electronic device 800B each have a mechanism that can adjust the left and right positions of lens 832 and display unit 820 so that they are optimally positioned according to the position of the user's eyes. It is also preferable that electronic device 800A and electronic device 800B each have a mechanism that can adjust the focus by changing the distance between lens 832 and display unit 820.

[0417] The user can wear electronic device 800A or electronic device 800B on the head using wearing unit 823. Note that, although FIG. 25A and other figures illustrate a shape similar to the temples of glasses (also called joints or temples), the shape is not limited to this. Wearing unit 823 may be shaped like a helmet or a band, for example, as long as it can be worn by the user.

[0418] The imaging unit 825 has a function of acquiring external information. Data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used for the imaging unit 825. Furthermore, multiple cameras may be provided to support multiple angles of view, such as telephoto and wide angle.

[0419] Although an example having the imaging unit 825 has been shown here, a distance measuring sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object may be provided. That is, the imaging unit 825 is one aspect of the detection unit. As the detection unit, for example, an image sensor or a range image sensor such as a LIDAR (Light Detection and Ranging) can be used. By using an image obtained by the camera and an image obtained by the range image sensor, more information can be obtained, enabling more accurate gesture operations.

[0420] 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 display unit 820, housing 821, and wearing unit 823. This allows a user to enjoy video and audio simply by wearing electronic device 800A, without the need for separate audio equipment such as headphones, earphones, or speakers.

[0421] The electronic device 800A and the electronic device 800B may each have an input terminal to which a cable can be connected for supplying a video signal from a video output device or the like and power for charging a battery provided in the electronic device.

[0422] The electronic device of one embodiment of the present invention may have a function of wirelessly communicating with earphone 750. Earphone 750 has a communication unit (not shown) and has a wireless communication function. Earphone 750 can receive information (e.g., audio data) from the electronic device through the wireless communication function. For example, electronic device 700A shown in FIG. 24A has a function of transmitting information to earphone 750 through the wireless communication function. Furthermore, electronic device 800A shown in FIG. 25A has a function of transmitting information to earphone 750 through the wireless communication function.

[0423] The electronic device may also have an earphone unit. Electronic device 700B shown in Fig. 24B has earphone unit 727. For example, earphone unit 727 and the control unit may be configured to be connected to each other by wire. Part of the wiring connecting earphone unit 727 and the control unit may be disposed inside housing 721 or wearing unit 723.

[0424] Similarly, electronic device 800B shown in Fig. 25B has earphone unit 827. For example, earphone unit 827 and control unit 824 can be configured to be connected to each other by wire. Part of the wiring connecting earphone unit 827 and control unit 824 may be disposed inside housing 821 or wearing unit 823. Furthermore, earphone unit 827 and wearing unit 823 may have magnets. This allows earphone unit 827 to be fixed to wearing unit 823 by magnetic force, which is preferable as it makes storage easier.

[0425] The electronic device may have an audio output terminal to which earphones or headphones can be connected. The electronic device may also have one or both of an audio input terminal and an audio input mechanism. For example, a sound collection device such as a microphone can be used as the audio input mechanism. By having the audio input mechanism, the electronic device may be endowed with the functionality of a so-called headset.

[0426] As described above, the electronic devices of one embodiment of the present invention are preferably either glasses-type devices (such as the electronic devices 700A and 700B) or goggle-type devices (such as the electronic devices 800A and 800B).

[0427] Furthermore, the electronic device of one embodiment of the present invention can transmit information to the earphone by wire or wirelessly.

[0428] Electronic device 6500 shown in FIG. 26A is a portable information terminal that can be used as a smartphone.

[0429] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508. The display portion 6502 has a touch panel function.

[0430] The display device of one embodiment of the present invention can be applied to the display portion 6502.

[0431] FIG. 26B is a schematic cross-sectional view including the end of the housing 6501 on the microphone 6506 side.

[0432] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0433] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by adhesive layers (not shown).

[0434] In an area outside the display unit 6502, a part of the display panel 6511 is folded back, and an FPC 6515 is connected to the folded back part. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0435] The flexible display of one embodiment of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted thereon while keeping the thickness of the electronic device small. Furthermore, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0436] 27A shows an example of a television device. A television device 7100 has a display unit 7000 built into a housing 7101. Here, the housing 7101 is supported by a stand 7103.

[0437] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0438] 27A can be operated using operation switches provided on the housing 7101 and a separate remote control 7111. Alternatively, a touch sensor may be provided in the display unit 7000, and the television 7100 may be operated by touching the display unit 7000 with a finger or the like. The remote control 7111 may have a display unit that displays information output from the remote control 7111. The channel and volume can be controlled using operation keys or a touch panel provided on the remote control 7111, and the video displayed on the display unit 7000 can be controlled.

[0439] The television device 7100 is configured to include a receiver, a modem, and the like. The receiver can receive general television broadcasts. In addition, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0440] 27B shows an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214. The housing 7211 includes a display portion 7000.

[0441] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0442] 27C and 27D show an example of digital signage.

[0443] 27C includes a housing 7301, a display unit 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0444] 27D shows a digital signage 7400 attached to a cylindrical pillar 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pillar 7401.

[0445] 27C and 27D, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0446] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it will attract people's attention, which can increase the advertising effectiveness of, for example, advertisements.

[0447] Applying a touch panel to the display unit 7000 is preferable because it not only displays images or videos on the display unit 7000 but also allows the user to intuitively operate it. Furthermore, when used to provide information such as route information or traffic information, intuitive operation can improve usability.

[0448] 27C and 27D, it is preferable that digital signage 7300 or digital signage 7400 can be linked via wireless communication with information terminal 7311 or information terminal 7411, such as a smartphone carried by a user. For example, advertising information displayed on display unit 7000 can be displayed on the screen of information terminal 7311 or information terminal 7411. Furthermore, the display on display unit 7000 can be switched by operating information terminal 7311 or information terminal 7411.

[0449] Furthermore, the digital signage 7300 or the digital signage 7400 can be made to run a game using the screen of the information terminal 7311 or the information terminal 7411 as an operation means (controller), thereby allowing an unspecified number of users to simultaneously participate in and enjoy the game.

[0450] The electronic device shown in Figures 28A to 28F has a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including the function of measuring force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone 9008, etc.

[0451] 28A to 28F, the display device of one embodiment of the present invention can be applied to the display portion 9001.

[0452] 28A to 28F have various functions. For example, they may have a function 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 using various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. Note that the functions of the electronic device are not limited to these, and the electronic device may have various other functions. The electronic device may have multiple display units. Furthermore, the electronic device may have a function to include a camera or the like to capture still images or videos and store them on a recording medium (external or built-in to the camera), a function to display the captured images on the display unit, etc.

[0453] The electronic devices shown in FIGS. 28A to 28F will be described in detail below.

[0454] FIG. 28A is a perspective view showing a mobile information terminal 9101. The mobile information terminal 9101 can be used as, for example, a smartphone. The mobile information terminal 9101 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, and the like. The mobile information terminal 9101 can display text and image information on multiple surfaces thereof. FIG. 28A shows an example in which three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the title of the email or SNS message, the sender's name, the date and time, the remaining battery level, and signal strength. Alternatively, the icon 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0455] 28B is a perspective view showing mobile information terminal 9102. Mobile information terminal 9102 has a function of displaying information on three or more sides of display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, while carrying mobile information terminal 9102 in a breast pocket of clothes, the user can check information 9053 displayed in a position that can be observed from above mobile information terminal 9102. The user can check the display without taking mobile information terminal 9102 out of the pocket and decide, for example, whether to answer a call.

[0456] FIG. 28C is a perspective view showing a wristwatch-type mobile information terminal 9200. The mobile information terminal 9200 can be used as, for example, a smart watch (registered trademark). The display surface of the display unit 9001 is curved, and display can be performed along the curved display surface. The mobile information terminal 9200 can also perform hands-free calling by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and reception with another information terminal and charge itself via a connection terminal 9006. Note that charging may be performed by wireless power supply.

[0457] 28D to 28F are perspective views showing a foldable mobile information terminal 9201. FIG. 28D shows the mobile information terminal 9201 in an unfolded state, FIG. 28F shows it in a folded state, and FIG. 28E is a perspective view showing a state in the process of changing from one of FIG. 28D and FIG. 28F to the other. The mobile information terminal 9201 is highly portable when folded, and has a seamless, wide display area when unfolded, providing excellent viewability of the display. The display unit 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display unit 9001 can be bent with a curvature radius of 0.1 mm or more and 150 mm or less.

[0458] This embodiment mode can be combined with other embodiment modes as appropriate. [Explanation of symbols]

[0459] 100A: display device, 100B: display device, 100C: display device, 100: display device, 101: layer including transistor, 110a: subpixel, 110b: subpixel, 110c: subpixel, 110: pixel, 111a: pixel electrode, 111b: pixel electrode, 111c: pixel electrode, 111: conductive film, 113: layer, 113a: first layer, 113b: second layer, 113c: third layer, 114a: first electron injection layer, 114b: second electron injection layer, 114c: third electron injection layer, 114: electron injection layer, 115: common electrode, 116: fourth electron transport layer, 118A: first sacrificial layer, 118a: first sacrificial layer, 118B: second sacrificial layer, 118b: second sacrificial layer, 118C: third sacrificial layer, 118c: third sacrificial layer, 119: resin layer, 120: substrate, 121A: insulating film, 121B: insulating film, 121: side wall, 122: side wall, 123: conductive layer, 130a: light emitting device, 130b: light emitting device, 130c: light emitting device, 131: protective layer, 132: protective layer, 134: gap, 140: connecting portion, 181A: first hole injection layer, 181a: first hole injection layer, 181B: second hole injection layer, 181b: second hole injection layer, 181C: third hole injection layer injection layer, 181c: third hole injection layer, 182A: first hole transport layer, 182a: first hole transport layer, 182B: second hole transport layer, 182b: second hole transport layer, 182C: third hole transport layer, 182c: third hole transport layer, 183A: first light-emitting layer, 183a: first light-emitting layer, 183B: second light-emitting layer, 183b: second light-emitting layer, 183C: third light-emitting layer, 183c: third light-emitting layer, 184A: first electron transport layer, 184a: first electron transport layer, 184B: second electron transport layer, 184b: second electron transport layer, 184C: third electron transport layer, 184c: third electron transport layer, 190a: resist mask, 190b: resist mask, 190c: resist mask, 240: capacitor, 241: conductive 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, 274a: conductive layer, 274b: conductive layer, 274: plug, 280: display module, 281: display section, 282: circuit section, 283a: pixel circuit, 283: pixel circuit section, 284a: pixel,284: pixel portion, 285: terminal portion, 286: wiring portion, 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, 500: display device, 501: electrode, 502: electrode, 503: region, 512B_1: light-emitting unit, 512B_ 2: light-emitting unit, 512B_3: light-emitting unit, 512G_1: light-emitting unit, 512G_2: light-emitting unit, 512G_3: light-emitting unit, 512R_1: light-emitting unit, 512R_2: light-emitting unit, 512R_3: light-emitting unit, 521: layer, 522: layer, 523B: light-emitting layer, 523G: light-emitting layer, 523R: light-emitting layer, 524: layer, 525: layer, 531: intermediate layer, 541: insulating layer, 542: insulating layer, 550B: light-emitting device, 550G: light-emitting device, 550R: light-emitting device, 700A: electronic device, 700B: electronic device, 721: housing, 723: Wearing part, 727: earphone part, 750: earphone, 751: display panel, 753: optical member, 756: display area, 757: frame, 758: nose pad, 772: electrode, 786a: EL layer, 786b: EL layer, 786: EL layer, 788: electrode, 800A: electronic device, 800B: electronic device, 820: display part, 821: housing, 822: communication part, 823: wearing part, 824: control part, 825: imaging part, 827: earphone part, 832: lens, 4411: light-emitting layer, 4412: light-emitting layer, 4413: light-emitting layer, 4420: layer, 4421: layer, 4422: layer, 443 0: layer, 4431: layer, 4432: layer, 4440: intermediate layer, 6500: electronic device, 6501: housing, 6502: display unit, 6503: power button, 6504: button, 6505: speaker, 6506: microphone, 6507: camera, 6508: light source, 6510: protective member, 6511: display panel, 6512: optical member, 6513: touch sensor panel, 6515: FPC, 6516: IC, 6517: printed circuit board, 6518: battery, 7000: display unit, 7100: television device, 7101: housing, 7103: stand, 7111: remote control operation device,7200: Notebook personal computer, 7211: Housing, 7212: Keyboard, 7213: Pointing device, 7214: External connection port, 7300: Digital signage, 7301: Housing 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 9000: Housing, 9001: Display unit, 9003: Speaker, 9005: Operation key, 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. a first light emitting device, a second light emitting device, and a first sidewall; the first light-emitting device has a first pixel electrode, a first light-emitting layer on the first pixel electrode, and a common electrode on the first light-emitting layer; the second light-emitting device has a second pixel electrode, a second light-emitting layer on the second pixel electrode, and the common electrode on the second light-emitting layer; the first light-emitting device and the second light-emitting device have a function of emitting light of different colors; The display device, wherein the first sidewall covers at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, a side surface of the first light-emitting layer, and a side surface of the second light-emitting layer.

2. In claim 1, the first light-emitting device includes a first hole injection layer on the first pixel electrode, a first hole transport layer on the first hole injection layer, and a first electron transport layer on the first light-emitting layer, each of which has a side surface covered by the first sidewall; and an electron injection layer on the first electron transport layer; the second light-emitting device has a second hole injection layer on the second pixel electrode, a second hole transport layer on the second hole injection layer, and a second electron transport layer on the second light-emitting layer, each of which has a side surface covered by the first sidewall, and further has the electron injection layer on the second electron transport layer.

3. In claim 1, the first light-emitting device includes a first hole injection layer on the first pixel electrode, a first hole transport layer on the first hole injection layer, a first electron transport layer on the first light-emitting layer, and a first electron injection layer on the first electron transport layer, each of which is covered on a side surface by the first sidewall; the second light-emitting device has a second hole injection layer on the second pixel electrode, a second hole transport layer on the second hole injection layer, a second electron transport layer on the second light-emitting layer, and a second electron injection layer on the second electron transport layer, each of which has a side surface covered by the first sidewall.

4. In claim 1, the first light-emitting device includes a first light-emitting unit on the first pixel electrode, a first intermediate layer on the first light-emitting unit, and a second light-emitting unit on the first intermediate layer, each of which has a side surface covered by the first sidewall; the second light-emitting device includes a third light-emitting unit on the second pixel electrode, a second intermediate layer on the third light-emitting unit, and a fourth light-emitting unit on the second intermediate layer, each of which has a side surface covered by the first sidewall; the first light-emitting unit and the second light-emitting unit each emit light of a first color; The display device, wherein the third light-emitting unit and the fourth light-emitting unit each emit light of a second color.

5. In any one of claims 1 to 4, It further has a second sidewall, the second sidewall covers at least a side surface of the first light-emitting layer and a side surface of the second light-emitting layer; The display device, wherein the first side wall covers at least a portion of a side surface of the second side wall.

6. In any one of claims 1 to 5, The display device further comprises a protective layer on the common electrode.

7. In any one of claims 1 to 6, the first light-emitting device and the second light-emitting device are disposed on an insulating layer; The display device, wherein the insulating layer has a recess.

Images