Display apparatus, display module, electronic equipment, and method for producing display apparatus

Abstract

Provided is a display apparatus exhibiting high definition or high resolution. A display apparatus comprising a first light-emitting device and a second light-emitting device, wherein: the first light-emitting device comprises a first electrically conductive layer, a second electrically conductive layer on the first electrically conductive layer, a first light-emitting layer on the second electrically conductive layer, and a common electrode on the first light-emitting layer; the second light-emitting device comprises a third electrically conductive layer, a fourth electrically conductive layer on the third electrically conductive layer, a second light-emitting layer on the fourth electrically conductive layer, and a common electrode on the second light-emitting layer; the second electrically conductive layer covers a lateral face of the first electrically conductive layer; the fourth electrically conductive layer covers a lateral face of the third electrically conductive layer; an end portion of the first light-emitting layer is aligned or substantially aligned with an end portion of the second electrically conductive layer; and an end portion of the second light-emitting layer is aligned or substantially aligned with an end portion of the fourth electrically conductive layer.

Description

Display device, display module, electronic device, and method for manufacturing the display device

[0001] 1. Field of the Invention One embodiment of the present invention relates to a display device, a display module, and an electronic device. 2. Description of the Related Art One embodiment of the present invention relates to a manufacturing method of a display 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.

[0003] In recent years, display devices have been 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 definition display devices. Devices requiring high-definition 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 referred to as a light-emitting element) has been developed. A light-emitting device (also referred to as an EL device or an EL element) utilizing an electroluminescence (hereinafter referred to as EL) phenomenon has features such as being easily thin and lightweight, being capable of high-speed response to an input signal, 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).

[0007] International Publication No. 2018 / 087625

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

[0009] For example, island-shaped light-emitting layers can be formed by vacuum deposition using a metal mask (also known as a shadow mask). However, this method can result in deviations in the shape and position of the island-shaped light-emitting layers from the design due to various factors, such as the accuracy of the metal mask, misalignment between the metal mask and the substrate, deflection of the metal mask, and the spread of the contours of the formed film due to vapor scattering, making it difficult to achieve high-definition and high-aperture displays. Furthermore, during deposition, the contours of the layer can become blurred, resulting in thin edges. In other words, the thickness of the island-shaped light-emitting layer can vary depending on the location. Furthermore, when fabricating large, high-resolution, or high-definition display devices, there is a concern that low manufacturing yields may be caused by low dimensional accuracy of the metal mask and deformation due to heat, etc.

[0010] Furthermore, when manufacturing display devices using a vacuum deposition method with a metal mask, the metal mask must be cleaned periodically, which stops the process. Therefore, it is desirable to prepare at least two lines of manufacturing equipment, and use one manufacturing equipment while the other is under maintenance. Considering mass production, multiple manufacturing equipment lines are required. Therefore, there is a problem in 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 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 small-sized display device.An object of one embodiment of the present invention is to provide a highly reliable display device.

[0012] 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 small-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.

[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.

[0014] One embodiment of the present invention is a display device having a first light-emitting device and a second light-emitting device. The first light-emitting device has a first conductive layer, a second conductive layer on the first conductive layer, a first light-emitting layer on the second conductive layer, and a common electrode on the first light-emitting layer. The second light-emitting device has a third conductive layer, a fourth conductive layer on the third conductive layer, a second light-emitting layer on the fourth conductive layer, and a common electrode on the second light-emitting layer. The second conductive layer covers side surfaces of the first conductive layer, the fourth conductive layer covers side surfaces of the third conductive layer, an edge of the first light-emitting layer is aligned or approximately aligned with an edge of the second conductive layer, and an edge of the second light-emitting layer is aligned or approximately aligned with an edge of the fourth conductive layer.

[0015] The display device preferably includes a first insulating layer that covers the side surfaces of the first light-emitting layer, the second light-emitting layer, the second conductive layer, and the fourth conductive layer, and the common electrode is preferably located on the first insulating layer.

[0016] The display device preferably includes a second insulating layer, the first insulating layer including an inorganic material, and the second insulating layer including an organic material, and the first insulating layer overlaps with the side surfaces of the first light-emitting layer and the second light-emitting layer via the first insulating layer.

[0017] The display device preferably includes a first layer. The first layer is located on the first light-emitting layer, and in a cross-sectional view, one end of the first layer is aligned or substantially aligned with an end of the first light-emitting layer and an end of the second conductive layer, and the other end of the first layer is located on the first light-emitting layer. The first layer preferably has a laminated structure of an inorganic insulating layer and a conductive layer on the inorganic insulating layer.

[0018] The first light-emitting device has a common layer between the first light-emitting layer and the common electrode, and the second light-emitting device has a common layer between the second light-emitting layer and the common electrode, and the common layer preferably has at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

[0019] One aspect of the present invention includes a first light-emitting device and a second light-emitting device, the first light-emitting device having a first conductive layer, a second conductive layer on the first conductive layer, a first EL layer on the second conductive layer, and a common electrode on the first EL layer, the second light-emitting device having a third conductive layer, a fourth conductive layer on the third conductive layer, a second EL layer on the fourth conductive layer, and a common electrode on the second EL layer, and the first EL layer having a first light-emitting unit on the second conductive layer, a first charge generation layer on the first light-emitting unit, and a first and a second light-emitting unit on the charge generating layer, wherein the second EL layer has a third light-emitting unit on a fourth conductive layer, a second charge generating layer on the third light-emitting unit, and a fourth light-emitting unit on the second charge generating layer, the second conductive layer covers sides of the first conductive layer, the fourth conductive layer covers sides of the third conductive layer, edges of the first EL layer are aligned or nearly aligned with edges of the second conductive layer, and edges of the second EL layer are aligned or nearly aligned with edges of the fourth conductive layer.

[0020] The display device preferably includes a first insulating layer that covers the side surfaces of the first EL layer, the second EL layer, the second conductive layer, and the fourth conductive layer, and the common electrode is preferably located on the first insulating layer.

[0021] The display device preferably includes a second insulating layer, the first insulating layer including an inorganic material, and the second insulating layer including an organic material, and the first insulating layer overlaps with the side surfaces of the first EL layer and the second EL layer, respectively, via the first insulating layer.

[0022] The display device preferably includes a first layer. The first layer is located on the first EL layer, and in a cross-sectional view, one end of the first layer is aligned or substantially aligned with an end of the first EL layer and an end of the second conductive layer, and the other end of the first layer is located on the first EL layer. The first insulating layer preferably covers an upper surface of the first layer. The first layer preferably has a laminated structure of an inorganic insulating layer and a conductive layer on the inorganic insulating layer.

[0023] The first light-emitting device has a common layer between the first EL layer and the common electrode, and the second light-emitting device has a common layer between the second EL layer and the common electrode, and the common layer preferably has at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

[0024] One embodiment of the present invention is a display module including a display device having any of the above structures, and including a connector such as a flexible printed circuit (FPC) or a tape carrier package (TCP) attached thereto, or a display module including an integrated circuit (IC) mounted thereon by a chip-on-glass (COG) method, a chip-on-film (COF) method, or the like.

[0025] 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.

[0026] One embodiment of the present invention includes forming a first conductive layer and a second conductive layer in an island shape on an insulating surface, forming a first conductive film on the first conductive layer and the second conductive layer, forming a first layer on the first conductive film, forming a first sacrificial layer on the first layer, processing the first layer and the first sacrificial layer so that ends of the first layer and ends of the first sacrificial layer are positioned outside ends of the first conductive layer and at least a part of a region of the first conductive film that overlaps with the second conductive layer is exposed, forming a second layer on the first sacrificial layer and the first conductive film, forming a second sacrificial layer on the second layer, and forming a second sacrificial layer on the second layer. and processing the second layer and the second sacrificial layer so that ends of the first and second sacrificial layers are located outside ends of the second conductive layer and at least a part of the first sacrificial layer is exposed; processing the first conductive film using the first sacrificial layer and the second sacrificial layer as a hard mask to form a third conductive layer between the first conductive layer and the first layer and a fourth conductive layer between the second conductive layer and the second layer; removing at least a part of the first sacrificial layer and the second sacrificial layer so that at least a part of the first layer and the second layer is exposed; and forming a common electrode on the first layer and the second layer.

[0027] After forming the third conductive layer and the fourth conductive layer, and before forming the common electrode, it is preferable to form a first insulating film that covers at least the side surfaces of the third conductive layer, the side surfaces of the fourth conductive layer, the side surfaces of the first layer, the side surfaces of the second layer, the side surfaces and top surfaces of the first sacrificial layer, and the side surfaces and top surfaces of the second sacrificial layer, and to process the first insulating film to form a first insulating layer that has one end located on the first layer and the other end located on the second layer in a cross-sectional view.

[0028] It is preferable to form a first insulating film using an inorganic material, and after forming the first insulating film, form a second insulating film using an organic material on the first insulating film, and process the second insulating film to form a second insulating layer having one end located on the first layer and the other end located on the second layer in a cross-sectional view. It is preferable to use a photosensitive resin as the organic material.

[0029] In the step of removing at least a portion of the first sacrificial layer, it is preferable to process the first sacrificial layer so that, in a cross-sectional view, one end is aligned or approximately aligned with an end of the first layer, and the other end is located on the first layer.

[0030] Before forming the common electrode, it is preferable to form at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer as a common layer on the first layer and the second layer.

[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 small-sized display device can be provided. According to one embodiment of the present invention, a highly reliable display device can be provided.

[0032] 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 small-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 a high yield can be provided.

[0033] 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.

[0034] FIG. 1A is a top view showing an example of a display device. FIGS. 1B and 1C are cross-sectional views showing an example of a display device. FIGS. 2A to 2F are top views showing an example of a pixel. FIGS. 3A to 3F are top views showing an example of a pixel. FIGS. 4A to 4H are top views showing an example of a pixel. FIGS. 5A to 5D are top views showing an example of a pixel. FIGS. 6A to 6D are top views showing an example of a pixel. FIGS. 6E to 6G are cross-sectional views showing an example of a display device. FIGS. 7A to 7F are top views showing an example of a manufacturing method of a display device. FIGS. 8A to 8C are cross-sectional views showing an example of a manufacturing method of a display device. FIGS. 9A to 9C are cross-sectional views showing an example of a manufacturing method of a display device. FIGS. 10A to 10C are cross-sectional views showing an example of a manufacturing method of a display device. FIGS. 11A to 11C are cross-sectional views showing an example of a manufacturing method of a display device. FIGS. 12A to 12C are cross-sectional views showing an example of a manufacturing method of a display device. FIGS. 13A to 13C are cross-sectional views illustrating an example of a method for manufacturing a display device. FIGS. 14A to 14C are cross-sectional views illustrating an example of a method for manufacturing a display device. FIGS. 15A to 15C are cross-sectional views illustrating an example of a method for manufacturing a display device. FIG. 16 is a cross-sectional view illustrating an example of a method for manufacturing a display device. FIGS. 17A and 17B are cross-sectional views illustrating an example of a method for manufacturing a display device. FIGS. 18A to 18C are cross-sectional views illustrating an example of a display device. FIGS. 19A and 19B are cross-sectional views illustrating an example of a display device. FIGS. 20A and 20B are cross-sectional views illustrating an example of a display device. FIGS. 21A and 21B are cross-sectional views illustrating an example of a display device. FIGS. 22A and 22B are cross-sectional views illustrating an example of a display device. FIG. 23 is a perspective view illustrating an example of a display device. FIG. 24A is a cross-sectional view illustrating an example of a display device. FIGS. 24B and 24C are cross-sectional views illustrating an example of a transistor. FIGS. 25A to 25D are cross-sectional views illustrating an example of a display device. FIG. 26 is a cross-sectional view illustrating an example of a display device. FIG. 27 is a cross-sectional view illustrating an example of a display device. 28A and 28B are perspective views showing an example of a display module. Figures 29A to 29C are cross-sectional views showing an example of a display device. Figure 30 is a cross-sectional view showing an example of a display device. Figure 31 is a cross-sectional view showing an example of a display device.Fig. 32 is a cross-sectional view showing an example of a display device. Fig. 33 is a cross-sectional view showing an example of a display device. Fig. 34A is a block diagram showing an example of a display device. Figs. 34B to 34D are diagrams showing an example of a pixel circuit. Figs. 35A to 35D are diagrams showing an example of a transistor. Figs. 36A and 36B are diagrams showing an example of an electronic device. Figs. 37A and 37B are diagrams showing an example of an electronic device. Figs. 38A and 38B are diagrams showing an example of an electronic device. Figs. 39A to 39D are diagrams showing an example of an electronic device. Figs. 40A to 40G are diagrams showing an example of an electronic device.

[0035] 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.

[0036] 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. Furthermore, when referring to similar functions, the same hatching pattern may be used and no particular reference numeral may be assigned.

[0037] 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.

[0038] 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."

[0039] Embodiment 1 In this embodiment, a display device according to one embodiment of the present invention and a manufacturing method thereof will be described with reference to FIGS.

[0040] In a manufacturing method of a display device according to one embodiment of the present invention, 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, and 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.

[0041] 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 metal mask having a fine pattern. 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 that is extremely vivid, has high contrast, and has high display quality. Furthermore, by providing a sacrificial layer (which may also be referred to as a mask 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.

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

[0043] 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, the above-described fabrication method processes a film formed to a uniform thickness, allowing island-shaped EL layers to 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 allows the fabrication of a display device that combines high definition and a high aperture ratio.

[0044] A display device according to one embodiment of the present invention includes a first conductive layer, a second conductive layer over the first conductive layer, and a light-emitting layer over the second conductive layer, where the second conductive layer covers a side surface of the first conductive layer and an edge of the second conductive layer is aligned with an edge of the light-emitting layer. One or both of the first conductive layer and the second conductive layer can be referred to as a pixel electrode. This structure can increase the aperture ratio compared to a structure in which an edge of the light-emitting layer is located inside an edge of the pixel electrode.

[0045] Furthermore, the light-emitting layer is provided on and in contact with the second conductive layer. By configuring the surface on which the light-emitting layer is formed to be made of a uniform material, the characteristics of the light-emitting device may be improved compared to a configuration in which the material of the surface on which the light-emitting layer is formed varies depending on the location (e.g., a configuration in which the light-emitting layer has a region formed on an insulating layer and a region formed on a conductive layer). For example, by appropriately selecting the material of the second conductive layer, adhesion to the light-emitting layer can be improved. Furthermore, by using a material with high barrier properties for the second conductive layer, the reliability of the light-emitting device can be improved.

[0046] 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 (electron transport layer or hole transport layer) on the light-emitting layer.

[0047] In light-emitting devices that emit 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. Examples of layers included in the EL layer include a light-emitting layer, a carrier injection layer (hole injection layer and electron injection layer), a carrier transport layer (hole transport layer and electron transport layer), and a carrier block layer (hole block layer and electron block layer). In a method for manufacturing 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 at least a portion of 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 (as a single film) for the light-emitting devices of each color. For example, the carrier injection layer and the common electrode can be formed in common for the light-emitting devices of each color. Meanwhile, the carrier injection layer is often a relatively highly conductive layer in the EL layer. Therefore, if the carrier injection layer comes into contact with the side surface of a part of the island-shaped EL layer or the side surface of the pixel electrode, the light-emitting device may be short-circuited. Furthermore, even when the carrier injection layer is provided in an island shape and a common electrode is formed in common for the light-emitting devices of each color, there is a risk of the light-emitting device short-circuiting due to contact between the common electrode and the side surface of the EL layer or the side surface of the pixel electrode.

[0048] Therefore, a display device according to one embodiment of the present invention includes an insulating layer that covers at least the side surfaces of the island-shaped light-emitting layer.

[0049] This prevents at least a portion of the island-shaped EL layer 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.

[0050] Furthermore, by providing the insulating layer, the gaps between adjacent island-shaped EL layers can be filled, thereby reducing the unevenness of the surface on which layers (such as a carrier injection layer and a common electrode) are formed on the island-shaped EL layers, making the surface flatter. This improves the coverage of the carrier injection layer or the common electrode, thereby preventing the common electrode from being broken.

[0051] In this specification and the like, the term "step discontinuity" refers to a phenomenon in which a layer, film, or electrode is divided due to the shape of the surface on which it is formed (for example, a step or the like).

[0052] The insulating layer can be provided so as to be in contact with the island-shaped EL layers, thereby preventing the EL layers from peeling off. The close contact between the insulating layer and the island-shaped EL layers provides the effect of fixing or adhering the adjacent island-shaped EL layers by the insulating layer.

[0053] When the insulating layer is provided, the opening of the cathode contact portion (connection portion 140 described later) can also be formed at the same time. That is, the insulating layer can be formed without adding an additional manufacturing process for providing the opening. For example, when the insulating layer is formed from a photosensitive resin, the insulating layer can be formed and the conductive layer in the cathode contact portion can be exposed with a single exposure.

[0054] 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; insulating layers provided so as to cover side surfaces of 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.

[0055] 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; insulating layers that are provided so as to cover side surfaces of 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.

[0056] Alternatively, a display device according to one embodiment of the present invention includes a pixel electrode, a first light-emitting unit over the pixel electrode, a charge generation layer (also referred to as an intermediate layer) over the first light-emitting unit, a second light-emitting unit over the charge generation layer, an insulating layer provided so as to cover side surfaces of the first light-emitting unit, the charge generation layer, and the second light-emitting unit, and a common electrode provided over the second light-emitting unit. Note that a common layer may be provided between the second light-emitting unit and the common electrode for light-emitting devices of each color.

[0057] Among EL layers, the hole injection layer, the electron injection layer, the charge generation layer, and the like are often layers with relatively high conductivity. In the display device of one embodiment of the present invention, the side surfaces of these layers are covered with an insulating layer, so that contact with a common electrode or the like can be suppressed. Therefore, short circuits in the light-emitting device can be suppressed, and the reliability of the light-emitting device can be improved.

[0058] By adopting such a configuration, a display device with high definition or resolution and high reliability can be manufactured. For example, there is no need to artificially increase the definition by applying a special pixel arrangement method such as a pen tile method, and even an arrangement method using three or more sub-pixels per pixel can realize an extremely high-definition display device. For example, a display device with a so-called stripe arrangement in which R, G, and B are each arranged in one direction, and a resolution of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, even 3000 ppi or more, or even 5000 ppi or more can be realized.

[0059] The insulating layer may have a single-layer structure or a laminated structure. In particular, it is preferable to use an insulating layer with a two-layer structure. For example, since the first layer of the insulating layer is formed in contact with the EL layer, it is preferably formed using an inorganic insulating material. In particular, it is preferable to form the insulating layer using atomic layer deposition (ALD), which causes less film damage during film formation. Alternatively, it is preferable to form the inorganic insulating layer using sputtering, chemical vapor deposition (CVD), or plasma enhanced CVD (PECVD), which have a faster film formation rate than ALD. This allows for the production of highly reliable display devices with high productivity. Furthermore, it is preferable to form the second insulating layer using an organic material so as to planarize the recesses formed in the first insulating layer.

[0060] For example, an aluminum oxide film formed by an ALD method can be used as the first insulating layer, and a photosensitive organic resin film can be used as the second insulating layer.

[0061] If the side surface of the EL layer and the photosensitive organic resin film are in direct contact, organic solvents that may be contained in the photosensitive organic resin film may damage the EL layer. By using an aluminum oxide film formed by the ALD method as the first layer of the insulating layer, it is possible to prevent the photosensitive organic resin film from being in direct contact with the side surface of the EL layer. This makes it possible to prevent the EL layer from being dissolved by an organic solvent.

[0062] Alternatively, an insulating layer having a single layer structure may be formed. For example, by forming an insulating layer having a single layer structure using an inorganic material, the insulating layer can be used as a protective insulating layer for the EL layer. This can improve the reliability of the display device. Furthermore, by forming an insulating layer having a single layer structure using an organic material, the insulating layer can fill the gap between adjacent EL layers and achieve planarization. This can improve the coverage of the EL layer and the common electrode (upper electrode) formed on the insulating layer. In particular, it is preferable to use an organic material that causes less damage to the EL layer.

[0063] Furthermore, in the display device of this embodiment, since there is no need to provide an insulating layer between the pixel electrode and the EL layer to cover the edge of the pixel electrode, the distance between adjacent light-emitting devices can be made extremely narrow. Therefore, the display device can have high definition or high resolution. Furthermore, a mask for forming the insulating layer is not required, which reduces the manufacturing cost of the display device.

[0064] [Configuration Example 1 of Display Device] FIGS. 1A to 1C illustrate a display device of one embodiment of the present invention.

[0065] 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. The connection section 140 can also be called a cathode contact section.

[0066] A stripe arrangement is applied to the pixel 110 shown in Fig. 1A. The pixel 110 shown in Fig. 1A is composed of three subpixels, 110a, 110b, and 110c. The subpixels 110a, 110b, and 110c each have a light-emitting device that emits light of a different color. Examples of the subpixels 110a, 110b, and 110c include three subpixels of red (R), green (G), and blue (B), and three subpixels of yellow (Y), cyan (C), and magenta (M).

[0067] The top surface shape of the sub-pixel shown in FIG. 1A corresponds to the top surface shape of the light-emitting region.

[0068] Furthermore, the circuit layout constituting the subpixels is not limited to the range of the subpixels shown in Fig. 1A and may be located outside of it. For example, some or all of the transistors included in the subpixel 110a may be located outside the range of the subpixel 110a shown in Fig. 1A. For example, the transistor included in the subpixel 110a may have a portion located within the range of the subpixel 110b and a portion located within the range of the subpixel 110c.

[0069] 1A shows the subpixels 110a, 110b, and 110c as having the same or approximately the same aperture ratio (size, or size of the light-emitting region), but this is not a limitation of one embodiment 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 aperture ratios may be equal or approximately equal.

[0070] 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.

[0071] 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 number of connection units 140 may be singular or plural.

[0072] 1B shows a cross-sectional view taken along dashed line X1-X2 in FIG. 1A, and FIG. 1C shows a cross-sectional view taken along dashed line Y1-Y2 in FIG. 1A.

[0073] 1B , display device 100 includes light-emitting devices 130a, 130b, and 130c provided on transistor-containing layer 101, and protective layer 131 provided to cover these light-emitting devices. Substrate 120 is bonded to protective layer 131 with resin layer 122. In addition, insulating layer 125 and insulating layer 127 on insulating layer 125 are provided in the regions between adjacent light-emitting devices.

[0074] 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.

[0075] 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. Configuration examples of the transistor-containing layer 101 will be described later in Embodiments 3 and 4.

[0076] The conductive layers 111a, 111b, and 111c are electrically connected to transistors provided in the transistor-containing layer 101. The conductive layers 111a, 111b, and 111c can be regarded as layers that electrically connect the light-emitting device and the transistors. Alternatively, the conductive layers 111a, 111b, and 111c can be regarded as parts of pixel electrodes of the light-emitting device.

[0077] The recesses of the conductive layers 111a, 111b, and 111c are preferably filled with a layer 128. The conductive layer 112a is preferably formed over the conductive layer 111a and the layer 128, the conductive layer 112b is preferably formed over the conductive layer 111b and the layer 128, and the conductive layer 112c is preferably formed over the conductive layer 111c and the layer 128. The conductive layers 112a, 112b, and 112c function as pixel electrodes of the light-emitting device.

[0078] The layer 128 has a function of planarizing the recesses of the conductive layers 111a, 111b, and 111c. By providing the layer 128, unevenness of the surface on which the EL layer is formed can be reduced, and coverage can be improved. Furthermore, by providing the conductive layers 112a, 112b, and 112c electrically connected to the conductive layers 111a, 111b, and 111c over the conductive layers 111a, 111b, and 111c and the layer 128, regions overlapping with the recesses of the conductive layers 111a, 111b, and 111c can also be used as light-emitting regions in some cases. This can increase the aperture ratio of the pixel.

[0079] The layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used as appropriate for the layer 128. In particular, the layer 128 is preferably formed using an insulating material.

[0080] An insulating layer containing an organic material can be suitably used as the layer 128. For example, acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, precursors of these resins, or the like can be used as the layer 128. Alternatively, a photosensitive resin can be used as the layer 128. The photosensitive resin can be a positive-type material or a negative-type material.

[0081] The conductive layer 112a is provided on the conductive layer 111a and the layer 128. The conductive layer 112a has a first region in contact with the upper surface of the conductive layer 111a and a second region in contact with the upper surface of the layer 128. It is preferable that the height of the upper surface of the conductive layer 111a in contact with the first region and the height of the upper surface of the layer 128 in contact with the second region are the same or approximately the same.

[0082] Similarly, the conductive layer 112b is provided on the conductive layer 111b and the layer 128. The conductive layer 112b has a first region in contact with the upper surface of the conductive layer 111b and a second region in contact with the upper surface of the layer 128. It is preferable that the height of the upper surface of the conductive layer 111b in contact with the first region and the height of the upper surface of the layer 128 in contact with the second region are the same or approximately the same.

[0083] The conductive layer 112c is provided on the conductive layer 111c and the layer 128. The conductive layer 112c has a first region in contact with the upper surface of the conductive layer 111c and a second region in contact with the upper surface of the layer 128. It is preferable that the height of the upper surface of the conductive layer 111c in contact with the first region and the height of the upper surface of the layer 128 in contact with the second region are the same or approximately the same.

[0084] 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).

[0085] As the light-emitting devices 130a, 130b, and 130c, for example, it is preferable to use an OLED (organic light-emitting diode) or a QLED (quantum-dot light-emitting diode). Examples of light-emitting substances (also referred to as light-emitting materials) included in the light-emitting devices include fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF materials). Note that the TADF material may be a material that is in thermal equilibrium between a singlet excited state and a triplet excited state. Such TADF materials have a short emission lifetime (excitation lifetime), which can suppress a decrease in efficiency in the high-brightness region of the light-emitting device. Furthermore, an inorganic compound (such as a quantum dot material) may be used as the light-emitting substance contained in the light-emitting device.

[0086] A light-emitting device has an EL layer between a pair of electrodes, one of which may be referred to as a pixel electrode and the other as a common electrode in this specification and the like.

[0087] 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.

[0088] The light-emitting device 130a includes a conductive layer 112a on the layer 101 including a transistor, a conductive layer 126a on the conductive layer 112a, a conductive layer 129a on the conductive layer 126a, an island-shaped first layer 113a on the conductive layer 129a, a fourth layer 114 on the island-shaped first layer 113a, and a common electrode 115 on the fourth layer 114. Note that the conductive layer 111a may also be considered a component of the light-emitting device 130a. The conductive layer 112a can function as a pixel electrode of the light-emitting device 130a. Note that at least one of the conductive layer 111a, the conductive layer 112a, the conductive layer 126a, and the conductive layer 129a functions as a pixel electrode of the light-emitting device 130a. Of the conductive layers 111a, 112a, 126a, and 129a, at least one layer that functions as a pixel electrode of the light-emitting device 130a is provided, and other conductive layers are not necessarily provided. In the light-emitting device 130a, the first layer 113a and the fourth layer 114 can be collectively referred to as an EL layer.

[0089] The structure of the light emitting device of this embodiment is not particularly limited, and may be a single structure or a tandem structure. An example of the structure of the light emitting device will be described later in the second embodiment.

[0090] The light-emitting device 130b includes a conductive layer 112b on the layer 101 including a transistor, a conductive layer 126b on the conductive layer 112b, a conductive layer 129b on the conductive layer 126b, an island-shaped second layer 113b on the conductive layer 129b, a fourth layer 114 on the island-shaped second layer 113b, and a common electrode 115 on the fourth layer 114. Note that the conductive layer 111b may also be considered a component of the light-emitting device 130b. The conductive layer 112b can function as a pixel electrode of the light-emitting device 130b. Note that at least one of the conductive layer 111b, the conductive layer 112b, the conductive layer 126b, and the conductive layer 129b functions as a pixel electrode of the light-emitting device 130b. Among the conductive layers 111b, 112b, 126b, and 129b, at least one layer that functions as a pixel electrode of the light-emitting device 130b is provided, and other conductive layers are not necessarily provided. In the light-emitting device 130b, the second layer 113b and the fourth layer 114 can be collectively referred to as an EL layer.

[0091] The light-emitting device 130c includes a conductive layer 112c on the layer 101 including a transistor, a conductive layer 126c on the conductive layer 112c, a conductive layer 129c on the conductive layer 126c, an island-shaped third layer 113c on the conductive layer 129c, a fourth layer 114 on the island-shaped third layer 113c, and a common electrode 115 on the fourth layer 114. The conductive layer 111c may also be considered a component of the light-emitting device 130c. The conductive layer 112c can function as a pixel electrode of the light-emitting device 130c. At least one of the conductive layer 111c, the conductive layer 112c, the conductive layer 126c, and the conductive layer 129c functions as a pixel electrode of the light-emitting device 130c. Among the conductive layers 111c, 112c, 126c, and 129c, at least one layer that functions as a pixel electrode of the light-emitting device 130c is provided, and other conductive layers are not necessarily provided. In the light-emitting device 130c, the third layer 113c and the fourth layer 114 can be collectively referred to as an EL layer.

[0092] The light-emitting devices of each color share the same film as a common electrode. The common electrode 115 shared by the light-emitting devices of each color is electrically connected to the conductive layer 123c provided in the connection portion 140 (see FIG. 1C ). This allows the same potential to be supplied to the common electrode 115 of the light-emitting devices of each color. The connection portion 140 may be provided with a conductive layer formed from the same material and in the same process as at least one of the conductive layers 111a, 112a, 126a, and 129a. FIG. 1C shows an example in which three conductive layers 123a, 123b, and 123c are formed from the same material and in the same process as the conductive layers 111a, 112a, and 129a.

[0093] In FIG. 1B , the conductive layers 111a, 112a, 126a, and 129a have different end positions. Specifically, the end of the conductive layer 112a is located outside the end of the conductive layer 111a, the end of the conductive layer 126a is located outside the end of the conductive layer 112a, and the end of the conductive layer 129a is located outside the end of the conductive layer 126a. The shapes of the conductive layers 111a, 112a, 126a, and 129a are not limited to the configuration shown in FIG. 1B . For example, the ends of at least two conductive layers may be aligned or approximately aligned. In other words, the top surface shapes of at least two conductive layers may be aligned or approximately aligned.

[0094] In addition, when the edges are aligned or approximately aligned, and when the top surface shapes are the same or approximately aligned, it can be said that at least a portion of the contours of the stacked layers overlap when viewed from above. For example, this includes cases where the upper and lower layers are processed using the same mask pattern or a portion of the same mask pattern. However, strictly speaking, the contours may not overlap, and the upper layer may be located inside the lower layer, or outside the lower layer. In these cases, it is also said that the edges are approximately aligned, or the top surface shapes are approximately aligned.

[0095] In the light-emitting device 130a, the first layer 113a covers the side surfaces of the conductive layers 111a, 112a, and 126a. The edges of the first layer 113a and the conductive layers 129a are aligned or substantially aligned. The edges of the first layer 113a are located outside the edges of the conductive layers 111a, 112a, and 126a. This configuration increases the aperture ratio of the pixel. The first layer 113a preferably covers the side surfaces of at least one of the conductive layers 111a, 112a, 126a, and 129a. The edges of the first layer 113a are preferably aligned or substantially aligned with the edges of at least one of the conductive layers 111a, 112a, 126a, and 129a. The same applies to the light-emitting devices 130b and 130c.

[0096] The side surfaces of the conductive layers 129a, 129b, 129c, the first layer 113a, the second layer 113b, and the third layer 113c are covered with the insulating layer 125. This prevents the fourth layer 114 (or the common electrode 115) from coming into contact with any of the side surfaces of the conductive layers 129a, 129b, 129c, the first layer 113a, the second layer 113b, and the third layer 113c, thereby preventing short circuits in the light-emitting device.

[0097] The insulating layer 125 can be in contact with the side surfaces of the conductive layers 129a, 129b, and 129c, the first layer 113a, the second layer 113b, and the third layer 113c.

[0098] The insulating layer 127 is provided on the insulating layer 125 so as to fill recesses formed in the insulating layer 125. The insulating layer 127 can be configured to overlap (or cover) side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c with the insulating layer 125 interposed therebetween. Furthermore, the insulating layer 127 can be configured to overlap side surfaces of the conductive layers 129a, 129b, and 129c with the insulating layer 125 interposed therebetween.

[0099] Note that either the insulating layer 125 or the insulating layer 127 does not necessarily have to be provided. For example, when the insulating layer 125 is not provided, the insulating layer 127 can be in contact with the side surfaces of the conductive layers 129a, 129b, and 129c, the first layer 113a, the second layer 113b, and the third layer 113c. The insulating layer 127 can be provided so as to fill the spaces between the EL layers of the light-emitting devices.

[0100] By filling the gaps between the EL layers of each light-emitting device with one or both of the insulating layers 125 and 127, peeling of the EL layers can be prevented, the reliability of the light-emitting devices can be improved, and the manufacturing yield of the light-emitting devices can be increased.

[0101] One or both of the insulating layer 125 and the insulating layer 127 may cover part of the top surface of each of the first layer 113a, the second layer 113b, and the third layer 113c. By covering not only the side surfaces but also the top surfaces of the EL layers with one or both of the insulating layer 125 and the insulating layer 127, peeling of the EL layers can be more effectively prevented, thereby improving the reliability of the light-emitting device. In addition, the manufacturing yield of the light-emitting device can be further improved.

[0102] Further, a sacrificial layer 118a is located over the first layer 113a. In FIG. 1B , one end of the sacrificial layer 118a is aligned or substantially aligned with an end of the first layer 113a, and the other end of the sacrificial layer 118a is located over the first layer 113a. As described above, the sacrificial layer used during the manufacturing of the display device of one embodiment of the present invention may remain. The same applies to the sacrificial layer 118b over the second layer 113b and the sacrificial layer 118c over the third layer 113c. Specifically, one end of the sacrificial layer 118b is aligned or substantially aligned with an end of the second layer 113b. The other end of the sacrificial layer 118b is located over the second layer 113b. One end of the sacrificial layer 118c is aligned or substantially aligned with an end of the third layer 113c. The other end of the sacrificial layer 118c is located on the third layer 113c.

[0103] Note that the display device of one embodiment of the present invention can have a structure including one or more of the sacrificial layers 118a, 118b, and 118c, or a structure including none of the three.

[0104] One or both of the insulating layer 125 and the insulating layer 127 may be provided on the sacrificial layer 118a. Similarly, one or both of the insulating layer 125 and the insulating layer 127 may be provided on the sacrificial layer 118b and the sacrificial layer 118c.

[0105] The fourth layer 114 and the common electrode 115 are provided over the first layer 113a, the second layer 113b, the third layer 113c, the insulating layer 125, and the insulating layer 127. Before the insulating layer 125 and the insulating layer 127 are provided, a step is generated between a region where the pixel electrode and the EL layer are provided and a region where the pixel electrode and the EL layer are not provided (a region between light-emitting devices). In the display device of one embodiment of the present invention, the insulating layer 125 and the insulating layer 127 can planarize the step, thereby improving the coverage of the fourth layer 114 and the common electrode 115. Therefore, poor connection due to a step in the common electrode 115 can be suppressed. Alternatively, an increase in electrical resistance caused by a local thinning of the common electrode 115 due to the step can be suppressed.

[0106] In order to improve the flatness of the surfaces on which the fourth layer 114 and the common electrode 115 are formed, it is preferable that the heights of the upper surfaces of the insulating layers 125 and 127 are the same or approximately the same as the height of the upper surface of at least one of the first layer 113a, the second layer 113b, and the third layer 113c. The upper surface of the insulating layer 127 preferably has a flat shape, and may have a convex portion, a convex curved surface, a concave curved surface, or a concave portion.

[0107] The insulating layer 125 has a region in contact with the side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c, and functions as a protective insulating layer for the first layer 113a, the second layer 113b, and the third layer 113c. By providing the insulating layer 125, impurities (oxygen, moisture, and the like) can be prevented from entering the inside from the side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c, thereby providing a highly reliable display device.

[0108] If the width (thickness) of the insulating layer 125 in the region in contact with the side surfaces of the first layer 113 a, the second layer 113 b, and the third layer 113 c is large in a cross-sectional view, the distance between the first layer 113 a, the second layer 113 b, and the third layer 113 c may become large, resulting in a low aperture ratio. Also, if the width (thickness) of the insulating layer 125 is small, the effect of suppressing impurities from penetrating into the interior from the side surfaces of the first layer 113 a, the second layer 113 b, and the third layer 113 c may become small. The width (thickness) of the insulating layer 125 in a region in contact with the side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c is preferably 3 nm to 200 nm, more preferably 3 nm to 150 nm, further preferably 5 nm to 150 nm, further preferably 5 nm to 100 nm, further preferably 10 nm to 100 nm, and further preferably 10 nm to 50 nm. By setting the width (thickness) of the insulating layer 125 in the above range, a display device having a high aperture ratio and high reliability can be obtained.

[0109] The insulating layer 125 can be an insulating layer containing an inorganic material. For example, an inorganic insulating film such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film can be used for the insulating layer 125. The insulating layer 125 may have a single-layer structure or a stacked-layer structure. Examples of oxide insulating films include a silicon oxide film, an aluminum oxide film, a magnesium oxide film, an indium gallium zinc 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 nitride insulating films include a silicon nitride film and an aluminum nitride film. Examples of oxynitride insulating films include a silicon oxynitride film and an aluminum oxynitride film. Examples of nitride oxide insulating films include a silicon nitride oxide film and an aluminum nitride oxide film. In particular, aluminum oxide is preferable because it has a high etching selectivity with respect to the EL layer and has a function of protecting the EL layer in the formation of the insulating layer 127 described later. In particular, by using an inorganic insulating film such as an aluminum oxide film, a hafnium oxide film, or a silicon oxide film formed by the ALD method as the insulating layer 125, it is possible to form an insulating layer 125 with few pinholes and excellent function of protecting the EL layer.

[0110] In this specification and elsewhere, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0111] The insulating layer 125 can be formed by a sputtering method, a CVD method, a PLD method, an ALD method, or the like. The insulating layer 125 is preferably formed by an ALD method because it has good coverage.

[0112] The insulating layer 127 provided on the insulating layer 125 has the function of planarizing recesses formed in the insulating layer 125 between adjacent light-emitting devices. In other words, the insulating layer 127 improves the flatness of the surface on which the common electrode 115 is formed. An insulating layer containing an organic material can be suitably used as the insulating layer 127. For example, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene-based resin, phenolic resin, and precursors of these resins can be used as the insulating layer 127. Alternatively, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used as the insulating layer 127. Alternatively, a photosensitive resin can be used as the insulating layer 127. A photoresist can be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0113] The difference in height between the top surface of the insulating layer 127 and the top surface of any of the first layer 113a, the second layer 113b, and the third layer 113c is, for example, preferably 0.5 times or less, more preferably 0.3 times or less, the thickness of the insulating layer 127. For example, the insulating layer 127 may be provided so that the top surface of any of the first layer 113a, the second layer 113b, and the third layer 113c is higher than the top surface of the insulating layer 127. For example, the insulating layer 127 may be provided so that the top surface of the insulating layer 127 is higher than the top surface of the light-emitting layer included in the first layer 113a, the second layer 113b, or the third layer 113c.

[0114] 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.

[0115] The pair of electrodes (pixel electrode and common electrode) of the light-emitting device can be formed from a material such as a metal, an alloy, an electrically conductive compound, or a mixture thereof. 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 alloy containing aluminum (aluminum alloy) such as an alloy of aluminum, nickel, and lanthanum (Al-Ni-La), and an alloy containing silver such as an alloy of silver and magnesium and an alloy of silver, palladium, and copper (Ag-Pd-Cu, also referred to as APC). Other examples of the metals that can be used include aluminum (Al), magnesium (Mg), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), as well as alloys containing appropriate combinations of these metals. Other examples of the metals that can be used include elements belonging to Group 1 or Group 2 of the periodic table (e.g., lithium (Li), cesium (Cs), calcium (Ca), and strontium (Sr)), rare earth metals such as europium (Eu), and ytterbium (Yb), as well as alloys containing appropriate combinations of these metals, graphene, and the like.

[0116] The 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 the light-emitting device have a microcavity structure, 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.

[0117] The semi-transmitting / semi-reflective electrode can have a laminated structure of a reflective electrode and an electrode that is transparent to visible light (also called a transparent electrode).

[0118] 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 Preferably, it is Ωcm or less.

[0119] For example, the conductive layers 111a and 112a may be formed of conductive layers functioning as reflective electrodes, and the conductive layers 126a and 129a may be formed of conductive layers functioning as transparent electrodes. For example, the conductive layer 111a may be formed of a metal such as titanium, the conductive layer 112a may be formed of a metal such as aluminum or an alloy such as APC, and the conductive layers 126a and 129a may be formed of a metal oxide such as titanium oxide or ITSO.

[0120] The first layer 113 a, the second layer 113 b, and the third layer 113 c are each provided in an island shape. Each of the first layer 113 a, the second layer 113 b, and the third layer 113 c has a light-emitting layer. It is preferable that the first layer 113 a, the second layer 113 b, and the third layer 113 c each have a light-emitting layer that emits light of a different color.

[0121] 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.

[0122] Examples of the light-emitting material include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0123] 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.

[0124] 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.

[0125] 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). As the one or more organic compounds, one or both of a hole-transporting material and an electron-transporting material can be used. Furthermore, as the one or more organic compounds, a bipolar material or a TADF material can be used.

[0126] The light-emitting layer preferably includes, 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-Triple 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, 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.

[0127] The first layer 113 a, the second layer 113 b, and the third layer 113 c may further include, as a layer other than the light-emitting layer, a layer containing a substance with a high hole-injection property, a substance with a high hole-transport property (also referred to as a hole-transport material), a hole-blocking material, a substance with a high electron-transport property (also referred to as an electron-transport material), a substance with a high electron-injection property, an electron-blocking material, a bipolar substance (a substance with high electron-transport property and high hole-transport property, also referred to as a bipolar material), or the like.

[0128] 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.

[0129] 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, as layers commonly formed in the light-emitting devices of each color. For example, a carrier injection layer (hole injection layer or electron injection layer) may be formed as the fourth layer 114. 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 commonly formed in the light-emitting devices of each color.

[0130] Each of the first layer 113a, the second layer 113b, and the third layer 113c preferably includes a light-emitting layer and a carrier transport layer on the light-emitting layer. 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.

[0131] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a substance 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).

[0132] 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 transporting material. The hole transporting material is a material having a concentration of 1×10 −６ cm２ A substance having a hole mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, a substance 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.

[0133] 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 concentration of 1×10 −６ cm ２ / 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.

[0134] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a substance with high electron injection properties. Examples of the substance with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the substance with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0135] 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 ), alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. 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.

[0136] 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.

[0137] 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.

[0138] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviation: BPhen), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), etc. can be used as the organic compound having an unshared electron pair. Note that NBPhen has a higher glass transition temperature (Tg) and is superior in heat resistance compared to BPhen.

[0139] In addition, when a light-emitting device with a tandem structure is fabricated, a charge-generating layer (also called an intermediate layer) is provided between two light-emitting units. The charge-generating layer has the function of injecting electrons into one of the two light-emitting units and holes into the other when a voltage is applied between a pair of electrodes.

[0140] The charge generation layer has at least a charge generation region. The charge generation region preferably contains an acceptor material, for example, a hole transport material and an acceptor material applicable to the hole injection layer described above.

[0141] The charge generation layer preferably includes a layer containing a substance with high electron injection properties. This layer may also be called an electron injection buffer layer. The electron injection buffer layer is preferably provided between the charge generation region and the electron transport layer. By providing the electron injection buffer layer, the injection barrier between the charge generation region and the electron transport layer can be alleviated, so that electrons generated in the charge generation region can be easily injected into the electron transport layer.

[0142] The electron injection buffer layer preferably contains an alkali metal or an alkaline earth metal, and may contain, for example, an alkali metal compound or an alkaline earth metal compound. Specifically, the electron injection buffer layer preferably contains an inorganic compound containing an alkali metal and oxygen, or an inorganic compound containing an alkaline earth metal and oxygen, and may contain an inorganic compound containing lithium and oxygen (lithium oxide (Li ２In addition, the electron injection buffer layer can be suitably made of the materials applicable to the electron injection layer described above.

[0143] The charge generation layer preferably has a layer containing a substance with high electron transport properties. This layer can also be called an electron relay layer. The electron relay layer is preferably provided between the charge generation region and the electron injection buffer layer. When the charge generation layer does not have an electron injection buffer layer, the electron relay layer is preferably provided between the charge generation region and the electron transport layer. The electron relay layer has the function of preventing interaction between the charge generation region and the electron injection buffer layer (or the electron transport layer) and smoothly transferring electrons.

[0144] For the electron relay layer, it is preferable to use a phthalocyanine-based material such as copper (II) phthalocyanine (abbreviated as CuPc) or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0145] It should be noted that the charge generation region, electron injection buffer layer, and electron relay layer may not be clearly distinguishable from one another depending on their cross-sectional shapes or characteristics.

[0146] The charge generation layer may contain a donor material instead of an acceptor material. For example, the charge generation layer may contain a layer containing an electron transport material and a donor material that can be used for the electron injection layer.

[0147] When light-emitting units are stacked, an increase in driving voltage can be suppressed by providing a charge generating layer between two light-emitting units.

[0148] 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.

[0149] It is preferable that the light-emitting devices 130a, 130b, and 130c have a protective layer 131. The reliability of the light-emitting devices can be improved by providing the protective layer 131. The protective layer 131 may have a single-layer structure or a stacked structure of two or more layers.

[0150] The protective layer 131 can be formed using at least one of an insulating film, a semiconductor film, and a conductive film.

[0151] The protective layer 131 has an inorganic film, which prevents oxidation of the common electrode 115 and prevents 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.

[0152] The protective layer 131 can be made of an inorganic insulating film such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film. Examples of oxide insulating 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 nitride insulating films include a silicon nitride film and an aluminum nitride film. Examples of oxynitride insulating films include a silicon oxynitride film and an aluminum oxynitride film. Examples of nitride oxide insulating films include a silicon nitride oxide film and an aluminum nitride oxide film.

[0153] The protective layer 131 preferably includes an insulating nitride film or an insulating nitride oxide film, and more preferably includes an insulating nitride film.

[0154] Alternatively, an inorganic film containing ITO, In—Zn oxide, Ga—Zn oxide, Al—Zn oxide, indium gallium zinc oxide (In—Ga—Zn oxide, also referred to as IGZO), or the like can be used for the protective layer 131. The inorganic film preferably has high resistance, specifically, preferably has higher resistance than the common electrode 115. The inorganic film may further contain nitrogen.

[0155] When light emitted from the light-emitting device is extracted through the protective layer 131, it is preferable that the protective layer 131 has 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.

[0156] For example, a stacked structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a stacked structure of an aluminum oxide film and an IGZO film on the aluminum oxide film can be used as the protective layer 131. By using such a stacked structure, impurities (water, oxygen, etc.) can be prevented from entering the EL layer side.

[0157] Furthermore, the protective layer 131 may include an organic film. For example, the protective layer 131 may include both an organic film and an inorganic film.

[0158] The protective layer 131 may have a two-layer structure formed by using different film formation methods. Specifically, the first layer of the protective layer 131 may be formed by the ALD method, and the second layer of the protective layer 131 may be formed by the sputtering method.

[0159] In the display device of this embodiment, the upper end portion of the pixel electrode is not covered with an insulating layer. Therefore, the distance between adjacent light-emitting devices can be made extremely narrow. Therefore, a high-definition or high-resolution display device can be obtained.

[0160] In this specification, etc., a device fabricated using a metal mask or an 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 an FMM may be referred to as a device with an MML (metal maskless) structure.

[0161] In this specification and the like, a structure in which different light-emitting layers are fabricated 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. The SBS structure allows the materials and configuration to be optimized for each light-emitting device, increasing the freedom of material and configuration selection and facilitating improvements in brightness and reliability.

[0162] In this specification and the like, a light-emitting device capable of emitting white light may be referred to as a white light-emitting device. Note that a white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0163] Light-emitting devices can be broadly divided into single structures and tandem structures. A single-structure device preferably has one light-emitting unit between a pair of electrodes, and the light-emitting unit includes one or more light-emitting layers. When two light-emitting layers are used to obtain white light emission, the light-emitting layers may be selected so that the emission colors of the two light-emitting layers are complementary to each other. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary to each other, a configuration in which the entire light-emitting device emits white light can be obtained. When three or more light-emitting layers are used to obtain white light emission, the emission colors of the three or more light-emitting layers may be combined to produce a configuration in which the entire light-emitting device emits white light.

[0164] A tandem-structure device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, light from the light-emitting layers of the light-emitting units may be combined to obtain white light emission. The configuration for obtaining white light emission is the same as that of the single-structure device. In a tandem-structure device, it is preferable to provide a charge-generating layer between the light-emitting units.

[0165] Furthermore, when comparing the above-described 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 it is desired to reduce power consumption, 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, and therefore the manufacturing cost can be reduced or the manufacturing yield can be increased, making it preferable.

[0166] The display device of this embodiment can reduce the distance between light-emitting devices. Specifically, the distance between light-emitting devices, the distance between EL layers, or the distance between pixel electrodes can be less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 10 nm or less. In other words, the distance between the side surface of the first layer 113 a and the side surface of the second layer 113 b or the distance between the side surface of the second layer 113 b and the side surface of the third layer 113 c 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.

[0167] A light-shielding layer may be provided on the surface of the substrate 120 facing the resin layer 122. Various optical members may be disposed on the outside of the 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 the substrate 120 may also be provided with an anti-static film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses the occurrence of scratches during use, an impact absorbing layer, etc.

[0168] 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 can increase the flexibility of the display device and realize a flexible display. A polarizing plate may also be used as the substrate 120.

[0169] 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.

[0170] 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).

[0171] 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.

[0172] 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.

[0173] 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.

[0174] The resin layer 122 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. Materials with low moisture permeability, such as epoxy resin, are particularly preferred. Two-component resins may also be used. Adhesive sheets or the like may also be used.

[0175] 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.

[0176] 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 display devices, and conductive layers (conductive layers functioning as pixel electrodes or common electrodes) in light-emitting devices.

[0177] 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.

[0178] [Pixel Layout] Next, pixel layouts different from that shown in FIG. 1A will be described. There are no particular limitations on the arrangement of sub-pixels, and various methods can be applied. Examples of sub-pixel arrangements include a stripe arrangement, an S-stripe arrangement, a matrix arrangement, a delta arrangement, a Bayer arrangement, and a pentile arrangement.

[0179] Examples of the top surface shape of the subpixel include a triangle, a quadrangle (including a rectangle and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, a circle, etc. Here, the top surface shape of the subpixel corresponds to the top surface shape of the light-emitting region of the light-emitting device.

[0180] An S-stripe arrangement is applied to the pixel 110 shown in Fig. 2A. The pixel 110 shown in Fig. 2A is composed of three subpixels, 110a, 110b, and 110c. For example, as shown in Fig. 3A, the subpixel 110a may be a blue subpixel B, the subpixel 110b may be a red subpixel R, and the subpixel 110c may be a green subpixel G.

[0181] The pixel 110 shown in FIG. 2B includes a subpixel 110a having a generally trapezoidal top surface shape with rounded corners, a subpixel 110b having a generally triangular top surface shape with rounded corners, and a subpixel 110c having a generally rectangular or hexagonal top surface shape with rounded corners. The subpixel 110a has a larger light-emitting area than the subpixel 110b. In this manner, the shape and size of each subpixel can be determined independently. For example, the subpixel having a more reliable light-emitting device can be made smaller in size. For example, as shown in FIG. 3B, the subpixel 110a may be a green subpixel G, the subpixel 110b may be a red subpixel R, and the subpixel 110c may be a blue subpixel B.

[0182] The pixels 124a and 124b shown in Fig. 2C are arranged in a Pentile arrangement. Fig. 2C shows an example in which a pixel 124a having subpixels 110a and 110b and a pixel 124b having subpixels 110b and 110c are arranged alternately. For example, as shown in Fig. 3C, the subpixel 110a may be a red subpixel R, the subpixel 110b may be a green subpixel G, and the subpixel 110c may be a blue subpixel B.

[0183] The pixels 124a and 124b shown in Figures 2D and 2E are arranged in a delta configuration. The pixel 124a has two subpixels (subpixels 110a and 110b) in the top row (first row) and one subpixel (subpixel 110c) in the bottom row (second row). The pixel 124b has one subpixel (subpixel 110c) in the top row (first row) and two subpixels (subpixels 110a and 110b) in the bottom row (second row). For example, as shown in Figure 3D, the subpixel 110a may be a red subpixel R, the subpixel 110b may be a green subpixel G, and the subpixel 110c may be a blue subpixel B.

[0184] FIG. 2D shows an example in which each subpixel has a substantially rectangular top surface shape with rounded corners, and FIG. 2E shows an example in which each subpixel has a circular top surface shape.

[0185] 2F shows an example in which subpixels of each color are arranged in a zigzag pattern. Specifically, when viewed from above, the positions of the upper edges of two subpixels arranged in the column direction (e.g., subpixels 110a and 110b, or subpixels 110b and 110c) are misaligned. For example, as shown in FIG. 3E, the subpixel 110a may be a red subpixel R, the subpixel 110b may be a green subpixel G, and the subpixel 110c may be a blue subpixel B.

[0186] In photolithography, the finer the pattern to be processed, the more significant the effect of light diffraction becomes. This reduces the fidelity of the photomask pattern when it is transferred by exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, it is likely to have rounded corners. As a result, the top surface shape of the subpixel may become a polygon with rounded corners, an ellipse, a circle, or the like.

[0187] Furthermore, in a manufacturing method of a display device according to one embodiment of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the material for the EL layer and the curing temperature of the resist material, the resist film may not be cured sufficiently. A resist film that is not cured sufficiently may have a shape that deviates from the desired shape during processing. As a result, the top surface shape of the EL layer may become a polygon with rounded corners, an ellipse, a circle, or the like. For example, when a resist mask with a square top surface shape is formed, a resist mask with a circular top surface shape may be formed, resulting in a circular top surface shape of the EL layer.

[0188] In order to form the top surface of the EL layer into a desired shape, a technique for correcting a mask pattern in advance (OPC (Optical Proximity Correction) technique) may be used so that the design pattern and the transfer pattern coincide with each other. Specifically, the OPC technique adds a correction pattern to the corners of figures on the mask pattern.

[0189] In addition, even in the pixel 110 to which the stripe arrangement shown in FIG. 1A is applied, for example, as shown in FIG. 3F, the subpixel 110a can be a red subpixel R, the subpixel 110b can be a green subpixel G, and the subpixel 110c can be a blue subpixel B.

[0190] As shown in Figures 4A to 4H, a pixel can be configured to have four types of sub-pixels.

[0191] The pixel 110 shown in FIGS. 4A to 4C is configured in a stripe arrangement.

[0192] FIG. 4A shows an example in which each subpixel has a rectangular top surface shape, FIG. 4B shows an example in which each subpixel has a top surface shape that is a combination of two semicircles and a rectangle, and FIG. 4C shows an example in which each subpixel has an elliptical top surface shape.

[0193] The pixels 110 shown in FIGS. 4D to 4F are arranged in a matrix.

[0194] Figure 4D is an example in which each subpixel has a square top surface shape, Figure 4E is an example in which each subpixel has an approximately square top surface shape with rounded corners, and Figure 4F is an example in which each subpixel has a circular top surface shape.

[0195] 4G and 4H show an example in which one pixel 110 is configured in two rows and three columns.

[0196] 4G has three subpixels (subpixels 110a, 110b, and 110c) in the top row (first row) and one subpixel (subpixel 110d) in the bottom row (second row). In other words, pixel 110 has subpixel 110a in the left column (first column), subpixel 110b in the center column (second column), subpixel 110c in the right column (third column), and subpixel 110d across these three columns.

[0197] The pixel 110 shown in FIG. 4H has three subpixels (subpixels 110a, 110b, and 110c) in the top row (first row) and three subpixels 110d in the bottom row (second row). In other words, the pixel 110 has subpixels 110a and 110d in the left column (first column), subpixels 110b and 110d in the center column (second column), and subpixels 110c and 110d in the right column (third column). By aligning the subpixels in the top and bottom rows as shown in FIG. 4H , it is possible to efficiently remove dust and other particles that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided.

[0198] The pixel 110 shown in Figures 4A to 4H is composed of four subpixels: 110a, 110b, 110c, and 110d. Each of the subpixels 110a, 110b, 110c, and 110d has a light-emitting device that emits light of a different color. The subpixels 110a, 110b, 110c, and 110d may be four-color subpixels of R, G, B, and white (W), four-color subpixels of R, G, B, and Y, or subpixels emitting red, green, blue, and infrared light. For example, as shown in Figures 5A to 5D, the subpixels 110a, 110b, 110c, and 110d may be red, green, blue, and white subpixels, respectively.

[0199] The display device according to one embodiment of the present invention may include a light-receiving device in a pixel.

[0200] Of the four types of sub-pixels included in the pixel 110 shown in FIGS. 4A to 4H, three may be configured to have a light-emitting device, and the remaining one may be configured to have a light-receiving device.

[0201] The light receiving device may be, for example, a pn-type or pin-type photodiode. The light receiving device functions as a photoelectric conversion device (also called a photoelectric conversion element) that detects light incident on the light receiving device and generates electric charges. The amount of electric charges generated by the light receiving device is determined based on the amount of light incident on the light receiving device.

[0202] In particular, it is preferable to use an organic photodiode having a layer containing an organic compound as the light-receiving device. Organic photodiodes can be easily made thin, lightweight, and large in area, and have a high degree of freedom in shape and design, making them applicable to a variety of display devices.

[0203] In one embodiment of the present invention, an organic EL device is used as the light-emitting device, and an organic photodiode is used as the light-receiving device. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, the organic photodiode can be built into a display device using the organic EL device.

[0204] The light-receiving device has an active layer that functions as at least a photoelectric conversion 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.

[0205] For example, the subpixels 110a, 110b, and 110c may be subpixels of three colors, R, G, and B, and the subpixel 110d may be a subpixel having a light receiving device.

[0206] Of the pair of electrodes that a light-receiving device has, one electrode functions as an anode and the other electrode functions as a cathode. The following describes an example in which the pixel electrode functions as the anode and the common electrode functions as the cathode. The light-receiving device can detect light incident on the light-receiving device, generate electric charges, and extract them as a current by applying a reverse bias between the pixel electrode and the common electrode. Alternatively, the pixel electrode may function as a cathode and the common electrode may function as an anode.

[0207] The same manufacturing method as for the light-emitting device can be applied to the light-receiving device. The island-shaped active layer (also called a photoelectric conversion layer) of the light-receiving device is formed by depositing a film to become the active layer on the entire surface and then processing it, rather than using a fine metal mask. Therefore, the island-shaped active layer can be formed with a uniform thickness. Furthermore, by providing a sacrificial layer on the active layer, damage to the active layer during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-receiving device.

[0208] Here, a layer shared by a light-receiving device and a light-emitting device may have different functions in the light-emitting device and in the light-receiving device. In this specification, components may be referred to based on their functions in the light-emitting device. For example, a hole injection layer functions as a hole injection layer in the light-emitting device and as a hole transport layer in the light-receiving device. Similarly, an electron injection layer functions as an electron injection layer in the light-emitting device and as an electron transport layer in the light-receiving device. Furthermore, a layer shared by a light-receiving device and a light-emitting device may have the same function in the light-emitting device and in the light-receiving device. A hole transport layer functions as a hole transport layer in both the light-emitting device and the light-receiving device, and an electron transport layer functions as an electron transport layer in both the light-emitting device and the light-receiving device.

[0209] The active layer of the light-receiving device includes a semiconductor. Examples of the semiconductor include inorganic semiconductors such as silicon and organic semiconductors containing organic compounds. In this embodiment, an example in which an organic semiconductor is used as the semiconductor of the active layer is shown. Using an organic semiconductor is preferable because the light-emitting layer and the active layer can be formed by the same method (e.g., vacuum deposition), allowing the use of a common manufacturing device.

[0210] The n-type semiconductor material of the active layer is fullerene (e.g., C ６０ Fullerene, C ７０ Examples of electron-accepting organic semiconductor materials include fullerenes and fullerene derivatives. Fullerenes have a soccer ball-like shape, and this shape is energetically stable. Fullerenes have deep (low) HOMO and LUMO levels. Because fullerenes have a deep LUMO level, they have extremely high electron-accepting (acceptor) properties. Normally, when π-electron conjugation (resonance) spreads on a plane, as in benzene, electron-donating (donor) properties increase, but fullerenes have a spherical shape, so they have high electron-accepting properties despite the large spread of π-electrons. High electron-accepting properties cause charge separation quickly and efficiently, making them useful as light-receiving devices. C ６０ Fullerene, C ７０ Both fullerenes and fluorenes have a wide absorption band in the visible light region, especially C ７０ Fullerene is C ６０ It is preferable because it has a larger π-electron conjugated system than fullerene and has a wide absorption band in the long wavelength region. Other fullerene derivatives include [6,6]-Phenyl-C71-butylic acid methyl ester (abbreviation: PC70BM), [6,6]-Phenyl-C61-butylic acid methyl ester (abbreviation: PC60BM), and 1',1",4',4"-Tetrahydro-di[1,4]methanenaphthaleno[1,2:2',3',56,60:2"3"][5,6]fullerene-C60 (abbreviation: ICBA).

[0211] Examples of n-type semiconductor materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, naphthalene derivatives, anthracene derivatives, coumarin derivatives, rhodamine derivatives, triazine derivatives, and quinone derivatives.

[0212] Examples of the p-type semiconductor material contained in the active layer include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin(II) phthalocyanine (SnPc), and quinacridone.

[0213] Examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, compounds having an aromatic amine skeleton, etc. Examples of p-type semiconductor materials include naphthalene derivatives, anthracene derivatives, pyrene derivatives, triphenylene derivatives, fluorene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, indolocarbazole derivatives, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, quinacridone derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, polythiophene derivatives, etc.

[0214] The HOMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the HOMO level of the electron-accepting organic semiconductor material, and the LUMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the LUMO level of the electron-accepting organic semiconductor material.

[0215] It is preferable to use a spherical fullerene as the electron-accepting organic semiconductor material and a planar organic semiconductor material as the electron-donating organic semiconductor material. Molecules with similar shapes tend to aggregate together, and when molecules of the same type aggregate, the energy levels of their molecular orbitals become close, which can improve carrier transport properties.

[0216] For example, the active layer is preferably formed by co-evaporating an n-type semiconductor and a p-type semiconductor, or may be formed by laminating an n-type semiconductor and a p-type semiconductor.

[0217] The light-receiving device may further include, as a layer other than the active layer, a layer containing a substance with high hole-transporting properties, a substance with high electron-transporting properties, a bipolar substance (a substance with high electron-transporting properties and high hole-transporting properties), etc. Furthermore, without being limited to the above, the light-receiving device may further include a layer containing a substance with high hole-injecting properties, a hole-blocking material, a substance with high electron-injecting properties, an electron-blocking material, etc.

[0218] The light-receiving device may 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-receiving device may be formed by a method such as vapor deposition (including vacuum deposition), transfer, printing, inkjet printing, or coating.

[0219] For example, a polymer compound such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) can be used as the hole transport material, and an inorganic compound such as molybdenum oxide or copper iodide (CuI) can be used as the electron transport material.

[0220] Furthermore, a polymer compound such as Poly[[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c']dithiophene-1,3-diyl]] polymer (abbreviated as PBDB-T) or a PBDB-T derivative, which functions as a donor, can be used in the active layer. For example, a method of dispersing an acceptor material in PBDB-T or a PBDB-T derivative can be used.

[0221] The active layer may also contain a mixture of three or more materials. For example, in order to broaden the absorption wavelength range, a third material may be mixed in addition to an n-type semiconductor material and a p-type semiconductor material. In this case, the third material may be a low-molecular-weight compound or a high-molecular-weight compound.

[0222] In a display device having a light-emitting device and a light-receiving device in each pixel, the pixel has a light-receiving function, and therefore it is possible to detect contact or proximity of an object while displaying an image. For example, in addition to displaying an image using all of the sub-pixels of the display device, some of the sub-pixels can emit light as a light source, while other sub-pixels can detect light, and the remaining sub-pixels can display an image.

[0223] A display device according to one embodiment of the present invention has a display portion in which light-emitting devices are arranged in a matrix, and can display an image on the display portion. Furthermore, light-receiving devices are arranged in a matrix on the display portion, and the display portion has an imaging function and / or a sensing function in addition to an image display function. The display portion can be used as an image sensor or a touch sensor. That is, by detecting light in the display portion, an image can be captured or the proximity or contact of an object (such as a finger, a hand, or a pen) can be detected. Furthermore, the display device according to one embodiment of the present invention can use a light-emitting device as a light source for a sensor. Therefore, a light-receiving portion and a light source are not required separately from the display device, and the number of components in an electronic device can be reduced.

[0224] In a display device of one embodiment of the present invention, when light emitted from a light-emitting device included in a display portion is reflected (or scattered) by an object, the light-receiving device can detect the reflected light (or scattered light). Therefore, imaging or touch detection is possible even in a dark place.

[0225] When the light receiving device is used as an image sensor, the display device can capture an image using the light receiving device. For example, the display device of the present embodiment can be used as a scanner.

[0226] For example, an image sensor can be used to acquire data related to biometric information such as fingerprints and palm prints. That is, a biometric authentication sensor can be built into the display device. By building a biometric authentication sensor into the display device, the number of components in the electronic device can be reduced compared to when a biometric authentication sensor is provided separately from the display device, and the electronic device can be made smaller and lighter.

[0227] Furthermore, when the light-receiving device is used as a touch sensor, the display device can detect the proximity or contact of an object using the light-receiving device.

[0228] The pixel shown in FIGS. 6A and 6B has subpixels G, B, R, and PS.

[0229] The pixels shown in Fig. 6A are arranged in a stripe pattern, while the pixels shown in Fig. 6B are arranged in a matrix pattern.

[0230] The pixel shown in FIGS. 6C and 6D has subpixels G, B, R, PS, and IRS.

[0231] 6C and 6D show an example in which one pixel is arranged across two rows and three columns. The top row (first row) has three subpixels (subpixel G, subpixel B, and subpixel R). In FIG. 6C , the bottom row (second row) has three subpixels (one subpixel PS and two subpixels IRS). In contrast, in FIG. 6D , the bottom row (second row) has two subpixels (one subpixel PS and one subpixel IRS). As shown in FIG. 6C , by aligning the subpixels in the top row and bottom row, it is possible to efficiently remove dust and other impurities that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided. The subpixel layout is not limited to the configurations shown in FIGS. 6A to 6D .

[0232] Subpixel R has a light-emitting device that emits red light, subpixel G has a light-emitting device that emits green light, and subpixel B has a light-emitting device that emits blue light.

[0233] The subpixels PS and IRS each have a light receiving device. The wavelength of light detected by the subpixels PS and IRS is not particularly limited.

[0234] 6C , the two subpixels IRS may each have an independent light receiving device, or may share one light receiving device, i.e., the pixel 110 shown in FIG. 6C may have one light receiving device for the subpixel PS and one or two light receiving devices for the subpixel IRS.

[0235] The light receiving area of ​​the subpixel PS is smaller than the light receiving area of ​​the subpixel IRS. The smaller the light receiving area, the narrower the imaging range, which makes it possible to suppress blurring in the imaging result and improve the resolution. Therefore, by using the subpixel PS, it is possible to perform imaging with higher definition or resolution than when using the subpixel IRS. For example, the subpixel PS can be used to perform imaging for personal authentication using a fingerprint, palm print, iris, pulse shape (including vein shape and artery shape), face, etc.

[0236] The light receiving device included in the subpixel PS preferably detects visible light, and preferably detects one or more of light of blue, purple, blue-purple, green, yellow-green, yellow, orange, red, etc. The light receiving device included in the subpixel PS may also detect infrared light.

[0237] The sub-pixel IRS can be used as a touch sensor (also called a direct touch sensor) or a near-touch sensor (also called a hover sensor, hover touch sensor, non-contact sensor, or touchless sensor). The wavelength of light to be detected by the sub-pixel IRS can be appropriately determined depending on the application. For example, it is preferable that the sub-pixel IRS detects infrared light. This enables touch detection even in dark places.

[0238] Here, the touch sensor or near-touch sensor can detect the proximity or contact of an object (such as a finger, hand, or pen).

[0239] A touch sensor can detect an object when the display device and the object are in direct contact with each other. A near-touch sensor can detect an object even if the object does not touch the display device. For example, a configuration in which the display device can detect an object when the distance between the display device and the object is between 0.1 mm and 300 mm, preferably between 3 mm and 50 mm, is preferred. This configuration allows the display device to be operated without the object directly touching it, in other words, it allows the display device to be operated in a non-contact (touchless) manner. This configuration reduces the risk of the display device becoming dirty or scratched, or allows the object to operate the display device without directly touching dirt (e.g., dust, viruses, etc.) attached to the display device.

[0240] Furthermore, the display device of one embodiment of the present invention can have a variable refresh rate. For example, the refresh rate can be adjusted (for example, adjusted within a range of 1 Hz to 240 Hz) depending on the content displayed on the display device to reduce power consumption. Furthermore, the drive frequency of the touch sensor or the near-touch sensor may be changed depending on the refresh rate. For example, when the refresh rate of the display device is 120 Hz, the drive frequency of the touch sensor or the near-touch sensor can be configured to be higher than 120 Hz (typically 240 Hz). This configuration enables low power consumption and an increased response speed of the touch sensor or the near-touch sensor.

[0241] The display device 100 shown in FIGS. 6E to 6G includes a layer 353 having a light-receiving device, a functional layer 355, and a layer 357 having a light-emitting device between a substrate 351 and a substrate 359.

[0242] The functional layer 355 includes a circuit for driving the light-receiving device and a circuit for driving the light-emitting device. The functional layer 355 may be provided with switches, transistors, capacitors, resistors, wiring, terminals, etc. Note that when the light-emitting device and the light-receiving device are driven by a passive matrix method, a configuration without switches and transistors may be used.

[0243] For example, as shown in Fig. 6E , when a finger 352 touches the display device 100, light emitted by a light-emitting device in the layer 357 having the light-emitting device is reflected by the light-receiving device in the layer 353 having the light-receiving device, and the reflected light is detected by the light-receiving device. This makes it possible to detect that the finger 352 has touched the display device 100. Alternatively, as shown in Figs. 6F and 6G , the display device may have a function of detecting or capturing an object that is close to (not in contact with) the display device. Fig. 6F shows an example of detecting a person's finger, and Fig. 6G shows an example of detecting information about the periphery, surface, or interior of a person's eye (such as the number of blinks, eyeball movement, and eyelid movement).

[0244] By mounting two types of light receiving devices in one pixel, two functions can be added in addition to the display function, making it possible to multi-function the display device.

[0245] In order to capture high-resolution images, it is preferable that the sub-pixels PS be provided in all pixels of the display device. On the other hand, the sub-pixels IRS used in touch sensors or near-touch sensors do not require higher accuracy than detection using the sub-pixels PS, so they may be provided in only some of the pixels of the display device. By making the number of sub-pixels IRS in the display device smaller than the number of sub-pixels PS, the detection speed can be increased.

[0246] As described above, by incorporating two types of light-receiving devices into one pixel, the display device of one embodiment of the present invention can add two functions in addition to a display function, thereby enabling the display device to have multiple functions. For example, a high-resolution imaging function and a sensing function such as a touch sensor or a near-touch sensor can be realized. Furthermore, by combining a pixel incorporating two types of light-receiving devices with a pixel having a different configuration, the functions of the display device can be further increased. For example, a pixel including a light-emitting device that emits infrared light or various sensor devices can be used.

[0247] [Example 1 of Manufacturing Method of Display Device] Next, an example of a manufacturing method of a display device will be described with reference to Figures 7 to 14. Figures 7A to 7F are top views showing a manufacturing method of a display device. Figures 8A to 8C show cross-sectional views taken along dashed dotted lines X1-X2 and Y1-Y2 in Figure 1A side by side. Figures 9 to 14 are similar to Figure 8.

[0248] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting display devices can be formed using a sputtering method, a CVD method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an ALD method, etc. CVD methods include a PECVD method and a thermal CVD method. One type of thermal CVD method is a metal organic chemical vapor deposition (MOCVD) method.

[0249] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) constituting 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.

[0250] 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, and chemical vapor deposition (CVD). In particular, functional layers included in the EL layer (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, etc.) can be formed by vapor deposition (vacuum deposition, etc.), coating methods (dip coating, die coating, bar coating, spin coating, spray coating, etc.), printing methods (inkjet printing, screen (stencil printing), offset (lithographic printing), flexography (relief printing), gravure, microcontact printing, etc.), etc.

[0251] 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.

[0252] 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.

[0253] In photolithography, the light used for exposure may be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. Other light sources that can be used include ultraviolet light, KrF laser light, ArF laser light, etc. Exposure may also be performed by immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays may also be used as the light used for exposure. An electron beam may also be used instead of the light used for exposure. Extreme ultraviolet light, X-rays, or an electron beam are preferred because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0254] For etching the thin film, dry etching, wet etching, sandblasting, or the like can be used.

[0255] 8A , conductive layers 111a, 111b, 111c, and 123a are formed over the layer 101 including the transistor. Then, a layer 128 is formed to fill recesses in the conductive layers 111a, 111b, and 111c. Then, a conductive layer 112a is formed over the conductive layer 111a and the layer 128, a conductive layer 112b is formed over the conductive layer 111b and the layer 128, a conductive layer 112c is formed over the conductive layer 111c and the layer 128, and a conductive layer 123b is formed over the conductive layer 123a. Next, a conductive layer 126a is formed over the conductive layer 112a, a conductive layer 126b is formed over the conductive layer 112b, and a conductive layer 126c is formed over the conductive layer 112c. Then, a conductive film 129z is formed over the layer 101 including the transistor and over the conductive layers 126a, 126b, 126c, and 123b.

[0256] The conductive layers 112a, 112b, and 112c are preferably provided so as to cover the side surfaces of the conductive layers 111a, 111b, and 111c, respectively. That is, the ends of the conductive layers 112a, 112b, and 112c are preferably located outside the ends of the conductive layers 111a, 111b, and 111c. Alternatively, the ends of the conductive layers 112a, 112b, and 112c may coincide with the ends of the conductive layers 111a, 111b, and 111c. Alternatively, the ends of the conductive layers 112a, 112b, and 112c may be located inside the ends of the conductive layers 111a, 111b, and 111c.

[0257] The conductive layers 126a, 126b, and 126c are preferably provided so as to cover the side surfaces of the conductive layers 112a, 112b, and 112c, respectively. In other words, the ends of the conductive layers 126a, 126b, and 126c are preferably located outside the ends of the conductive layers 112a, 112b, and 112c. Alternatively, the ends of the conductive layers 126a, 126b, and 126c may coincide with the ends of the conductive layers 112a, 112b, and 112c. Alternatively, they may be located inside the ends of the conductive layers 112a, 112b, and 112c.

[0258] The conductive film 129 is preferably provided so as to cover the top and side surfaces of the conductive layers 126a, 126b, and 126c.

[0259] Note that, although the following description will be mainly given taking the conductive layers 111a, 112a, and 126a as an example, the same can be said for the conductive layers 111b, 112b, and 126b and the conductive layers 111c, 112c, and 126c.

[0260] In this embodiment, an example in which the positions of the ends of the conductive layers 111a, 112a, and 126a are different is shown, but the present invention is not limited to this. For example, at least two of the films that will become the conductive layers 111a, 112a, and 126a may be processed in the same process or using the same mask pattern. This is preferable because it enables a reduction in the number of processes or the number of masks. Note that, among the conductive layers 111a, 112a, and 126a, layers formed by processing in the same process or using the same mask pattern have the same or approximately the same ends. In other words, the top surface shapes of at least two of the conductive layers 111a, 112a, and 126a may be the same or approximately the same.

[0261] The conductive film 129 is a conductive film that will be processed in a later step. Here, an example is shown in which three layers, namely, conductive layers 111a, 112a, and 126a, are formed first, and then the conductive film 129 is processed. However, the conductive layer that is formed first may be a single layer, two layers, or four or more layers. The conductive film that is processed in a later step may be two or more layers.

[0262] Furthermore, the connection portion 140 can be provided with a conductive layer formed of the same material and in the same process as at least one of the conductive layers 111a, 112a, and 126a. Alternatively, a conductive layer formed by processing the conductive film 129 may be provided. In this embodiment, an example is shown in which the conductive layers 123a and 123b provided in the connection portion 140 are formed of the same material and in the same process as the conductive layers 111a and 112a. The conductive layer provided in the connection portion 140 may have a single-layer structure or a stacked-layer structure.

[0263] Then, a first layer 113A is formed over the conductive film 129, a first sacrificial layer 118A is formed over the first layer 113A, and a second sacrificial layer 119A is formed over the first sacrificial layer 118A.

[0264] 8A , in the cross-sectional view between Y1 and Y2, the end of the first layer 113A on the connection portion 140 side is located more inward (closer to the display portion) 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), the regions where the first layer 113A, the first sacrificial layer 118A, and the second sacrificial layer 119A are formed can be varied. In one embodiment of the present invention, a light-emitting device is formed using a resist mask. However, by combining the resist mask with an area mask as described above, a light-emitting device can be manufactured through a relatively simple process.

[0265] The above-described structures applicable to pixel electrodes can be applied to the conductive layers 111a, 112a, and 126a and the conductive film 129. The conductive layers 111a, 112a, and 126a and the conductive film 129 can be formed by, for example, a sputtering method or a vacuum evaporation method.

[0266] The first layer 113A is a layer that will later become the first layer 113a. Therefore, the above-described structure applicable to the first layer 113a can be applied. The first layer 113A can be formed by a method such as a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, or a coating method. The first layer 113A is preferably formed by a vapor deposition method. When forming a film using a vapor deposition method, a premixed material may be used. Note that in this specification and the like, a premixed material is a composite material in which multiple materials are blended or mixed in advance.

[0267] The first sacrificial layer 118A and the second sacrificial layer 119A are made of a film that is highly resistant to the processing conditions of the first layer 113A and the second layer 113B and third layer 113C formed in later steps, specifically, a film that has a large etching selectivity with respect to various EL layers.

[0268] The first sacrificial layer 118A and the second sacrificial layer 119A can be formed by, for example, sputtering, ALD (including thermal ALD and PEALD), CVD, or vacuum evaporation. The first sacrificial layer 118A, which is formed on and in contact with the EL layer, is preferably formed using a method that causes less damage to the EL layer than the second sacrificial layer 119A. For example, the first sacrificial layer 118A is preferably formed using ALD or vacuum evaporation rather than sputtering. The first sacrificial layer 118A and the second sacrificial layer 119A are formed at a temperature lower than the heat-resistant temperature limit of the EL layer (typically, 200° C. or lower, preferably 100° C. or lower, and more preferably 80° C. or lower).

[0269] It is preferable to use a film that can be removed by wet etching for the first sacrificial layer 118A and the second sacrificial layer 119A, since wet etching can reduce damage to the first layer 113A during processing of the first sacrificial layer 118A and the second sacrificial layer 119A compared to dry etching.

[0270] It is also preferable to use a film for the first sacrificial layer 118A that has a large etching selectivity with respect to the second sacrificial layer 119A.

[0271] 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, the hole transport layer, the light-emitting layer, and the 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.

[0272] In this embodiment, an example is shown in which the sacrificial layer is formed with a two-layer structure of a first sacrificial layer and a second sacrificial layer, but the sacrificial layer may have a single-layer structure or a stacked structure of three or more layers.

[0273] The first sacrificial layer 118A and the second sacrificial layer 119A can each be made of, 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.

[0274] The first sacrificial layer 118A and the second sacrificial layer 119A 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, or tantalum, or an alloy material containing such a metal material. In particular, it is preferable to use a low-melting-point material such as aluminum or silver. Using a metal material capable of blocking ultraviolet light for one or both of the first sacrificial layer 118A and the second sacrificial layer 119A can prevent the EL layer from being exposed to ultraviolet light, thereby suppressing deterioration of the EL layer.

[0275] The first sacrificial layer 118A and the second sacrificial layer 119A 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 or the second sacrificial layer 119A 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, indium tin oxide containing silicon can be used.

[0276] In addition, instead of the above 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.

[0277] Furthermore, various inorganic insulating films that can be used for the protective layer 131 can be used for the first sacrificial layer 118A and the second sacrificial layer 119A. 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 and the second sacrificial layer 119A. For example, an aluminum oxide film can be formed as the first sacrificial layer 118A or the second sacrificial layer 119A by the ALD method. Using the ALD method is preferable because it can reduce damage to the base (especially the EL layer, etc.).

[0278] For example, an inorganic insulating film (e.g., an aluminum oxide film) formed by ALD can be used as the first sacrificial layer 118A, and an In—Ga—Zn oxide film formed by sputtering can be used as the second sacrificial layer 119A. Alternatively, an inorganic insulating film (e.g., an aluminum oxide film) formed by ALD can be used as the first sacrificial layer 118A, and an aluminum film or tungsten film formed by sputtering can be used as the second sacrificial layer 119A.

[0279] The first sacrificial layer 118A and the second sacrificial layer 119A may be made of a material that is soluble in a chemically stable solvent, at least for the film located at the top of the first layer 113A. In particular, materials that dissolve in water or alcohol are suitable for use as the first sacrificial layer 118A or the second sacrificial layer 119A. When forming a film of such a material, it is preferable to apply the material dissolved in a solvent such as water or alcohol by a wet film formation method, and then perform a heat treatment to evaporate the solvent. In this case, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to the EL layer.

[0280] The first sacrificial layer 118A and the second sacrificial layer 119A may be formed using a wet film formation method such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0281] The first sacrificial layer 118A and the second sacrificial layer 119A may be made of an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin.

[0282] 8A, a resist mask 190a is formed on the second sacrificial layer 119A. The resist mask can be formed by applying a photosensitive resin (photoresist) and then performing exposure and development.

[0283] The resist mask may be made of either a positive resist material or a negative resist material.

[0284] The resist mask 190a is provided in a position that overlaps with an area that will later become the sub-pixel 110a. As shown in Fig. 7A, it is preferable that the resist mask 190a has an island-shaped pattern for each sub-pixel 110a. Alternatively, as shown in Fig. 7D, the resist mask 190a may have a strip-shaped pattern for multiple sub-pixels 110a that are aligned in a row (aligned in the Y direction in Fig. 7D).

[0285] Here, the resist mask 190a is preferably formed so that the edges of the resist mask 190a are positioned outside the edges of the conductive layer 126a, thereby enabling the edges of the first layer 113a and the conductive layer 129a, which will be formed later, to be positioned outside the edges of the conductive layer 126a.

[0286] The resist mask 190 a may also be provided at a position overlapping the connection section 140 .

[0287] 8B , a resist mask 190a is used to remove a portion of the second sacrificial layer 119A to form a sacrificial layer 119a. The sacrificial layer 119a remains in the region that will later become the subpixel 110a and the region that will later become the connection portion 140.

[0288] When etching the second sacrificial layer 119A, it is preferable to use etching conditions with a high selectivity so that the first sacrificial layer 118A is not removed by the etching. Furthermore, since the EL layer is not exposed when processing the second sacrificial layer 119A, the range of processing methods available is wider than when processing the first sacrificial layer 118A. Specifically, even when a gas containing oxygen is used as an etching gas when processing the second sacrificial layer 119A, deterioration of the EL layer can be further suppressed.

[0289] Thereafter, the resist mask 190a is removed. For example, the resist mask 190a can be removed by ashing using oxygen plasma. Alternatively, the resist mask 190a can be removed by ashing using oxygen gas and CF ４ , C ４ F ８ , S.F. ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ Alternatively, a noble gas (also referred to as a rare gas) such as He may be used. Alternatively, the resist mask 190a may be removed by wet etching. At this time, the first sacrificial layer 118A is located on the outermost surface and the first layer 113A is not exposed, so that damage to the first layer 113A can be suppressed in the process of removing the resist mask 190a. Furthermore, the range of options for removing the resist mask 190a can be expanded.

[0290] Next, as shown in FIG. 8C, the sacrificial layer 119a is used as a mask (also referred to as a hard mask) to remove part of the first sacrificial layer 118A, thereby forming a sacrificial layer 118a.

[0291] The first sacrificial layer 118A and the second sacrificial layer 119A can be processed by wet etching or dry etching, respectively. The first sacrificial layer 118A and the second sacrificial layer 119A are preferably processed by anisotropic etching.

[0292] Compared to the case of using dry etching, the use of wet etching can reduce damage to the first layer 113A during processing of the first sacrificial layer 118A and the second sacrificial layer 119A. When using wet etching, it is preferable to use, for example, a developer, a tetramethylammonium hydroxide (TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed solution containing two or more of these.

[0293] When dry etching is used, deterioration of the first layer 113A can be suppressed by not using a gas containing oxygen as an etching gas. ４ , C ４ F ８ , S.F. ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ It is preferable to use a gas containing a noble gas (also called a rare gas) such as He or the like as an etching gas.

[0294] For example, when an aluminum oxide film formed by ALD is used as the first sacrificial layer 118A, CHF ３ The first sacrificial layer 118A can be processed by dry etching using He. When an In-Ga-Zn oxide film formed by sputtering is used as the second sacrificial layer 119A, the second sacrificial layer 119A can be processed by wet etching using diluted phosphoric acid. ４ The second sacrificial layer 119A may be processed by dry etching using Ar and diluted phosphoric acid. Alternatively, the second sacrificial layer 119A may be processed by wet etching using diluted phosphoric acid. When a tungsten film formed by sputtering is used as the second sacrificial layer 119A, CF ４ and O ２ , or CF ４ and Cl ２ and O ２ The second sacrificial layer 119A can be processed by dry etching using the above.

[0295] Next, as shown in FIG. 8C, the sacrificial layers 119a and 118a are used as a hard mask to remove a portion of the first layer 113A, thereby forming a first layer 113a.

[0296] 8C , in the region corresponding to the subpixel 110a, a stacked structure of the conductive film 129, the first layer 113a, the sacrificial layer 118a, and the sacrificial layer 119a remains on the conductive layer 126a. In the region corresponding to the connection portion 140, a stacked structure of the sacrificial layer 118a and the sacrificial layer 119a remains on the conductive layer 123b.

[0297] The end of the first layer 113a is located outside the end of the conductive layer 126a. With this structure, the aperture ratio of the pixel can be increased.

[0298] At this stage, the conductive film 129 has not yet been processed. Since the conductive film 129 covers the top and side surfaces of the conductive layers 111a, 111b, 111c, 112a, 112b, 112c, 126a, 126b, and 126c, subsequent steps can be performed without exposing these conductive layers. Therefore, these conductive layers can be prevented from corroding in an etching step or the like. In addition, the conductive film 129 is preferably formed using a material that is resistant to damage and corrosion in an etching step or the like.

[0299] When the conductive film 129 covers the top and side surfaces of the conductive layers 111a, 112a, 126a, and the like, for example, the yield of the light-emitting device can be improved, and the display quality of the light-emitting device can be improved.

[0300] Through the above steps, regions of the first layer 113A, the first sacrificial layer 118A, and the second sacrificial layer 119A that do not overlap with the resist mask 190a can be removed.

[0301] Note that a part of the first layer 113A may be removed using the resist mask 190a, and then the resist mask 190a may be removed.

[0302] The first layer 113A is preferably processed by anisotropic etching, particularly anisotropic dry etching, or wet etching.

[0303] When dry etching is used, deterioration of the first layer 113A can be suppressed by not using a gas containing oxygen as an etching gas.

[0304] Alternatively, a gas containing oxygen may be used as the etching gas. When the etching gas contains oxygen, the etching rate can be increased. Therefore, etching can be performed under low power conditions while maintaining a sufficiently high etching rate. This can suppress damage to the first layer 113A. Furthermore, problems such as adhesion of reaction products that occur during etching can be suppressed.

[0305] When dry etching is used, for example, H ２ , C.F. ４ , C ４ F ８ , S.F. ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ It is preferable to use a gas containing one or more of the following gases as the etching gas: H, Ar, or a noble gas (also called a rare gas). Alternatively, it is preferable to use a gas containing one or more of these gases and oxygen as the etching gas. Alternatively, oxygen gas may be used as the etching gas. Specifically, for example, H ２ and a gas containing Ar, or CF ４ A gas containing CF and He can be used as an etching gas. ４ A gas containing He and oxygen can be used as the etching gas.

[0306] Next, as shown in FIG. 9A, a second layer 113B is formed on the sacrificial layer 119a and the conductive film 129, a first sacrificial layer 118B is formed on the second layer 113B, and a second sacrificial layer 119B is formed on the first sacrificial layer 118B.

[0307] As shown in FIG. 9A, in the cross section taken along line Y1-Y2, the end of second layer 113B on the connection section 140 side is located more inward (toward the display section) than the end of first sacrificial layer 118B.

[0308] The second layer 113B is a layer that will later become the second layer 113b. The second layer 113b emits light of a different color from that of the first layer 113a. The structure, materials, and the like that can be applied to the second layer 113b are similar to those of the first layer 113a. The second layer 113B can be formed using a method similar to that for the first layer 113A.

[0309] The first sacrificial layer 118B can be formed using a material that can be used for the first sacrificial layer 118A. The second sacrificial layer 119B can be formed using a material that can be used for the second sacrificial layer 119A.

[0310] Next, as shown in FIG. 9A, a resist mask 190b is formed on the second sacrificial layer 119B.

[0311] The resist mask 190b is provided in a position that overlaps with an area that will later become the sub-pixel 110b. As shown in Fig. 7B, it is preferable that the resist mask 190b has an island-shaped pattern for each sub-pixel 110b. Alternatively, as shown in Fig. 7E, the resist mask 190b may have a strip-shaped pattern for a plurality of sub-pixels 110b arranged in a row.

[0312] Here, the resist mask 190b is preferably formed so that an edge of the resist mask 190b is positioned outside an edge of the conductive layer 126b, thereby allowing an edge of the second layer 113b to be formed later to be positioned outside an edge of the conductive layer 126b.

[0313] The resist mask 190b may also be provided at a position that overlaps with the region that will later become the connection portion 140.

[0314] 9B, a resist mask 190b is used to remove a portion of the second sacrificial layer 119B to form a sacrificial layer 119b, which remains in the region that will later become the sub-pixel 110b.

[0315] Thereafter, the resist mask 190b is removed, and then, using the sacrificial layer 119b as a hard mask, a part of the first sacrificial layer 118B is removed to form a sacrificial layer 118b.

[0316] Then, as shown in FIG. 9C, the sacrificial layers 119b and 118b are used as a hard mask to remove a portion of the second layer 113B, thereby forming a second layer 113b.

[0317] 9C , in the region corresponding to the subpixel 110b, a stacked structure of the conductive film 129, the second layer 113b, the sacrificial layer 118b, and the sacrificial layer 119b remains on the conductive layer 126b. In the region corresponding to the connection portion 140, a stacked structure of the sacrificial layer 118a and the sacrificial layer 119a remains on the conductive layer 123b.

[0318] An end portion of the second layer 113b is positioned outside an end portion of the conductive layer 126b. With this structure, the aperture ratio of the pixel can be increased.

[0319] Through the above steps, regions of the second layer 113B, the first sacrificial layer 118B, and the second sacrificial layer 119B that do not overlap with the resist mask 190b can be removed. These layers can be processed using a method that can be applied to processing the first layer 113A, the first sacrificial layer 118A, and the second sacrificial layer 119A.

[0320] Next, as shown in FIG. 10A, a third layer 113C is formed on the sacrificial layer 119a, the sacrificial layer 119b, and the conductive film 129, a first sacrificial layer 118C is formed on the third layer 113C, and a second sacrificial layer 119C is formed on the first sacrificial layer 118C.

[0321] As shown in FIG. 10A, in the cross-sectional view taken along line Y1-Y2, the end of the third layer 113C on the connection section 140 side is located more inward (toward the display section) than the end of the first sacrificial layer 118C.

[0322] The third layer 113C is a layer that will later become the third layer 113c. The third layer 113c emits light of a different color from the first layer 113a and the second layer 113b. The structure, materials, and the like that can be applied to the third layer 113c are similar to those of the first layer 113a. The third layer 113C can be formed using a method similar to that for the first layer 113A.

[0323] The first sacrificial layer 118C can be formed using a material that can be used for the first sacrificial layer 118A. The second sacrificial layer 119C can be formed using a material that can be used for the second sacrificial layer 119A.

[0324] Next, as shown in FIG. 10A, a resist mask 190c is formed on the second sacrificial layer 119C.

[0325] The resist mask 190c is provided in a position that overlaps with an area that will later become the sub-pixel 110c. As shown in Fig. 7C, it is preferable that the resist mask 190c has an island-shaped pattern for each sub-pixel 110c. Alternatively, as shown in Fig. 7F, the resist mask 190c may have a strip-shaped pattern for a plurality of sub-pixels 110c arranged in a row.

[0326] Here, the resist mask 190c is preferably formed so that an edge of the resist mask 190c is positioned outside an edge of the conductive layer 126c, thereby allowing an edge of the third layer 113c to be formed later to be positioned outside an edge of the conductive layer 126c.

[0327] The resist mask 190c may also be provided at a position that overlaps with the region that will later become the connection section 140.

[0328] 10B, a resist mask 190c is used to remove a portion of the second sacrificial layer 119C to form a sacrificial layer 119c, which remains in the region that will later become the sub-pixel 110c.

[0329] Thereafter, the resist mask 190c is removed, and then, using the sacrificial layer 119c as a hard mask, a part of the first sacrificial layer 118C is removed to form a sacrificial layer 118c.

[0330] Then, as shown in FIG. 10C, the sacrificial layers 119c and 118c are used as a hard mask to remove a portion of the third layer 113C, thereby forming the third layer 113c.

[0331] 10C , in a region corresponding to the subpixel 110 c, a stacked structure of the conductive film 129, the third layer 113 c, the sacrificial layer 118 c, and the sacrificial layer 119 c remains on the conductive layer 126 c. In addition, in a region corresponding to the connection portion 140, a stacked structure of the sacrificial layer 118 a and the sacrificial layer 119 a remains on the conductive layer 123 b.

[0332] An end portion of the third layer 113c is positioned outside an end portion of the conductive layer 126c. With this structure, the aperture ratio of the pixel can be increased.

[0333] Through the above steps, regions of the third layer 113C, the first sacrificial layer 118C, and the second sacrificial layer 119C that are not overlapped with the resist mask 190c can be removed. These layers can be processed using a method that can be applied to processing the first layer 113A, the first sacrificial layer 118A, and the second sacrificial layer 119A.

[0334] Note that the side surfaces of the first layer 113 a, the second layer 113 b, and the third layer 113 c are preferably perpendicular or substantially perpendicular to the surface on which they are to be formed. For example, the angle formed between the surface on which they are to be formed and the side surfaces is preferably 60 degrees or more and 90 degrees or less.

[0335] Next, as shown in FIG. 11A, the conductive film 129 is processed using the sacrificial layers 118a, 118b, and 118c and the sacrificial layers 119a, 119b, and 119c as hard masks to form conductive layers 129a, 129b, 129c, and 123c.

[0336] The conductive film 129 can be processed by a wet etching method or a dry etching method. The conductive film 129 is preferably processed by anisotropic etching.

[0337] As described above, the conductive film 129 is processed using the sacrificial layers 118a, 118b, and 118c and the sacrificial layers 119a, 119b, and 119c as masks. Therefore, the top surface shapes of the first layer 113a and the conductive layer 129a are the same or approximately the same. Similarly, the top surface shapes of the second layer 113b and the conductive layer 129b are the same or approximately the same, and the top surface shapes of the third layer 113c and the conductive layer 129c are the same or approximately the same. That is, the end of the first layer 113a and the end of the conductive layer 129a are aligned or approximately aligned. Similarly, the end of the second layer 113b and the end of the conductive layer 129b are aligned or approximately aligned. The end of the third layer 113c and the conductive layer 129c are aligned or approximately aligned.

[0338] 11A, the sacrificial layers 119a, 119b, and 119c are removed, thereby exposing the sacrificial layer 118a on the conductive layer 111a, the sacrificial layer 118b on the conductive layer 111b, the sacrificial layer 118c on the conductive layer 111c, and the sacrificial layer 118a on the conductive layer 123c.

[0339] As will be described later in a second example of a manufacturing method, the process may proceed to the step of forming the insulating film 125A without removing the sacrificial layers 119a, 119b, and 119c.

[0340] The sacrificial layer removal process can be performed using a method similar to that used in the sacrificial layer processing process. In particular, by using a wet etching method, damage to the first layer 113 a, the second layer 113 b, and the third layer 113 c during the removal of the sacrificial layer can be reduced compared to when a dry etching method is used.

[0341] The sacrificial layer may also be removed by dissolving it in a solvent such as water or alcohol, such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0342] After removing the sacrificial layer, a drying treatment may be performed to remove water contained in the EL layer and water adsorbed on the surface of the EL layer. For example, a heat treatment can be performed in an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 120°C or lower. A reduced pressure atmosphere is preferred because it allows drying at a lower temperature.

[0343] Next, as shown in FIG. 11B, an insulating film 125A is formed to cover the conductive layers 129a, 129b, and 129c, the first layer 113a, the second layer 113b, the third layer 113c, and the sacrificial layers 118a, 118b, and 118c.

[0344] The insulating film 125A can be, for example, an inorganic insulating film such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film. Examples of oxide insulating films include a silicon oxide film, an aluminum oxide film, a magnesium oxide film, a gallium oxide film, a germanium oxide film, a 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 nitride insulating films include a silicon nitride film and an aluminum nitride film. Examples of oxynitride insulating films include a silicon oxynitride film and an aluminum oxynitride film. Examples of nitride oxide insulating films include a silicon nitride oxide film and an aluminum nitride oxide film. Metal oxide films such as an indium gallium zinc oxide film may also be used.

[0345] The insulating film 125A preferably functions as a barrier insulating film against at least one of water and oxygen, or has a function of suppressing diffusion of at least one of water and oxygen, or has a function of capturing or fixing (also referred to as gettering) at least one of water and oxygen.

[0346] In this specification and the like, a barrier insulating film refers to an insulating film having barrier properties. Furthermore, in this specification and the like, the term "barrier properties" refers to a function of suppressing the diffusion of a corresponding substance (also referred to as low permeability), or a function of capturing or fixing a corresponding substance (also referred to as gettering).

[0347] The insulating film 125A has the above-mentioned barrier insulating film function or gettering function, which makes it possible to suppress the intrusion of impurities (typically water or oxygen) that can diffuse into each light-emitting device from the outside. With this configuration, it is possible to provide a display device with excellent reliability.

[0348] Next, as shown in FIG. 11C, an insulating layer 127 is formed on the insulating film 125A.

[0349] The insulating layer 127 may be made of an organic material. Examples of organic materials include acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin, and precursors of these resins. Alternatively, the insulating layer 127 may be made of an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin. Alternatively, the insulating layer 127 may be made of a photosensitive resin. A photoresist may be used as the photosensitive resin. The photosensitive resin may be a positive-type material or a negative-type material.

[0350] The insulating layer 127 can be patterned by applying a photosensitive resin, exposing it to light, and developing it.

[0351] Etching may be performed to adjust the height of the surface of the insulating layer 127. The insulating layer 127 may be processed by ashing using oxygen plasma, for example.

[0352] There are no particular limitations on the method for forming the film that will become the insulating layer 127, and the film can be formed using a wet film-forming method such as spin coating, dipping, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, knife coating, etc. In particular, it is preferable to form the film that will become the insulating layer 127 by spin coating.

[0353] The insulating film 125A and the insulating layer 127 are preferably formed by a method that causes less damage to the EL layer. In particular, since the insulating film 125A is formed in contact with the side surface of the EL layer, it is preferably formed by a method that causes less damage to the EL layer than the insulating layer 127. Furthermore, the insulating film 125A and the insulating layer 127 are each formed at a temperature lower than the heat resistance temperature of the EL layer (typically 200° C. or lower, preferably 100° C. or lower, and more preferably 80° C. or lower). For example, an aluminum oxide film can be formed as the insulating film 125A by an ALD method. The ALD method is preferable because it can reduce film formation damage and form a film with high coverage.

[0354] Next, as shown in FIG. 12A, the insulating film 125A and at least a portion of the sacrificial layers 118a, 118b, and 118c are removed to expose the first layer 113a, the second layer 113b, and the third layer 113c.

[0355] The sacrificial layers 118a, 118b, and 118c and the insulating film 125A may be removed in separate steps or in the same step. For example, if the sacrificial layers 118a, 118b, and 118c and the insulating film 125A are films formed using the same material, they can be removed in the same step, which is preferable. For example, it is preferable to form the sacrificial layers 118a, 118b, and 118c and the insulating film 125A by an ALD method, and it is more preferable to form an aluminum oxide film by an ALD method.

[0356] 12A, the region of the insulating film 125A that overlaps with the insulating layer 127 remains as the insulating layer 125. Furthermore, the regions of the sacrificial layers 118a, 118b, and 118c that overlap with the insulating layer 127 also remain.

[0357] In this manner, the display device of one embodiment of the present invention can have a structure in which the sacrificial layers remain. Note that depending on the shape of the insulating layer 127, all of the sacrificial layers 118a, 118b, and 118c may be removed. Therefore, the sacrificial layers 118a, 118b, and 118c do not necessarily remain in the display device.

[0358] The insulating layer 125 (and further the insulating layer 127) is provided so as to cover the side surfaces of the conductive layers 129a, 129b, 129c, the first layer 113a, the second layer 113b, and the third layer 113c. This prevents films to be formed later from coming into contact with the side surfaces of these layers, thereby preventing the light-emitting device from shorting out. Furthermore, damage to the conductive layers 129a, 129b, 129c, the first layer 113a, the second layer 113b, and the third layer 113c in later processes can be prevented.

[0359] The sacrificial layers 118a, 118b, and 118c can be removed using the same method as that used in the sacrificial layer processing step. The sacrificial layers 119a, 119b, and 119c can be removed using the same method as that used in the sacrificial layer processing step.

[0360] The insulating film 125A is preferably processed by dry etching. The insulating film 125A is preferably processed by anisotropic etching. The insulating film 125A can be processed using an etching gas that can be used when processing a sacrificial layer.

[0361] Next, as shown in FIG. 12B, a fourth layer 114 is formed to cover the insulating layer 125, the insulating layer 127, the first layer 113a, the second layer 113b, and the third layer 113c.

[0362] 12B shows an example in which the fourth layer 114 is provided in the connection portion 140. Depending on the level of conductivity of the fourth layer 114, the fourth layer 114 may be provided in the connection portion 140.

[0363] 12C , the end of the fourth layer 114 on the connection section 140 side is preferably located more inward (closer to the display section) than the connection section 140. For example, when forming the fourth layer 114, it is preferable to use a mask to define the film formation area.

[0364] The materials that can be used for the fourth layer 114 are as described above. The fourth 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 fourth layer 114 may also be formed using a premixed material.

[0365] The fourth layer 114 is provided to cover the top surfaces of the first layer 113a, the second layer 113b, and the third layer 113c, as well as the top surface and side surfaces of the insulating layer 127. Here, if the fourth layer 114 has high conductivity, contact between the fourth layer 114 and any side surface of the conductive layers 129a, 129b, and 129c or the first layer 113a, the second layer 113b, or the third layer 113c may cause a short circuit in the light-emitting device. However, in the display device of one embodiment of the present invention, the insulating layers 125 and 127 cover the side surfaces of the conductive layers 129a, 129b, and 129c and the first layer 113a, the second layer 113b, and the third layer 113c, thereby preventing the highly conductive fourth layer 114 from contacting these layers, thereby preventing a short circuit in the light-emitting device. This can improve the reliability of the light emitting device.

[0366] Furthermore, since the insulating layers 125 and 127 are filled between the first layer 113a and the second layer 113b and between the second layer 113b and the third layer 113c, the surface on which the fourth layer 114 is to be formed has smaller steps and is flatter than when the insulating layers 125 and 127 are not provided. This allows the coverage of the fourth layer 114 to be improved.

[0367] Then, as shown in FIG. 12B or 12C, the common electrode 115 is formed on the fourth layer 114 (and on the conductive layer 123c).

[0368] 12B, the conductive layer 123c and the common electrode 115 are electrically connected via the fourth layer 114. In addition, in Fig. 12C, the conductive layer 123c and the common electrode 115 are in direct contact with each other, thereby being electrically connected.

[0369] A mask for defining a film formation area may be used when forming the common electrode 115. Alternatively, the mask may not be used when forming the common electrode 115, and the common electrode 115 may be processed using a resist mask or the like after the common electrode 115 is formed.

[0370] The materials that can be used for the common electrode 115 are as described above. The common electrode 115 can be formed by, for example, sputtering or vacuum deposition. Alternatively, a film formed by deposition and a film formed by sputtering may be stacked.

[0371] Thereafter, a protective layer 131 is formed on the common electrode 115. Furthermore, a substrate 120 is attached onto the protective layer 131 using a resin layer 122, whereby the display device 100 shown in FIG.

[0372] The materials and film formation methods that can be used for the protective layer 131 are as described above. Examples of the film formation method for the protective layer 131 include a vacuum deposition method, a sputtering method, a CVD method, and an ALD method. The protective layer 131 may have a single-layer structure or a multilayer structure.

[0373] It should be noted that there is no particular limitation on the shape of the insulating layer 127. Figures 13A to 13C and 14A show modified examples of the cross-sectional view shown in Figure 12B. Specifically, these modified examples each have a different shape of the insulating layer 127.

[0374] As shown in FIG. 12B, the upper surface of the insulating layer 127 can be configured to have a recessed shape in the center and its vicinity in cross section, that is, a shape having a concave curved surface.

[0375] As shown in FIG. 13A, the upper surface of the insulating layer 127 may have a shape in which the center and its vicinity bulge in cross section, that is, a shape having a convex curve.

[0376] As shown in FIG. 13B, the insulating layer 127 may have a flat portion on the top surface in a cross-sectional view.

[0377] 12B and 13A show an example in which the top surfaces of the insulating layers 125 and 127 are lower than the top surfaces of the first layer 113a, the second layer 113b, and the third layer 113c. Alternatively, the top surface of the insulating layer 127 may be higher than the top surfaces of the first layer 113a, the second layer 113b, and the third layer 113c.

[0378] 13B , at least one of the heights of the top surfaces of the first layer 113a, the second layer 113b, and the third layer 113c may be the same or approximately the same as the heights of the top surfaces of the insulating layers 125 and 127. In this case, the layers formed on the insulating layer 127, the first layer 113a, the second layer 113b, and the third layer 113c can be formed more flatly, and the coverage of the layers can be further improved.

[0379] 13C , the height of at least one of the top surfaces of the first layer 113a, the second layer 113b, and the third layer 113c may be the same or approximately the same as the top surface of the insulating layer 125, and the top surface of the insulating layer 127 may have a concave curved surface. Alternatively, the top surface of the insulating layer 127 may have a convex curved surface.

[0380] The upper surface of the insulating layer 127 may have one or both of a convex curved surface and a concave curved surface. The number of convex curved surfaces and concave curved surfaces that the upper surface of the insulating layer 127 has is not limited, and may be one or more.

[0381] Furthermore, the height of the upper surface of insulating layer 125 and the height of the upper surface of insulating layer 127 may be the same or approximately the same, or may be different from each other. For example, the height of the upper surface of insulating layer 125 may be lower or higher than the height of the upper surface of insulating layer 127.

[0382] As shown in FIG. 14A , the heights of the top surfaces of the first layer 113a, the second layer 113b, and the third layer 113c may be different. The height of the top surface of the insulating layer 125 on the first layer 113a side is the same as or approximately the same as the top surface of the first layer 113a, and the height of the top surface of the second layer 113b on the second layer 113b side is the same as or approximately the same as the top surface of the second layer 113b. The top surface of the insulating layer 127 has a gentle slope, with the first layer 113a side being higher and the second layer 113b side being lower. In this way, the heights of the insulating layers 125 and 127 are preferably the same as the top surfaces of the adjacent EL layers. Alternatively, the top surface may be flat, being the same as the top surface of one of the adjacent EL layers.

[0383] 14B , the insulating layer 125 does not necessarily have to be provided. In this case, it is preferable to use an organic material that causes less damage to the first layer 113 a, the second layer 113 b, and the third layer 113 c for the insulating layer 127. For example, it is preferable to use an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or an alcohol-soluble polyamide resin for the insulating layer 127.

[0384] 14C , the fourth layer 114 may be omitted, and a common electrode 115 may be formed to cover the insulating layer 127, the first layer 113 a, the second layer 113 b, and the third layer 113 c. In other words, all layers constituting the EL layer may be formed separately for each light-emitting device that emits light of a different color. In this case, the EL layer of each light-emitting device is formed in an island shape.

[0385] Here, contact between the common electrode 115 and any side surface of the conductive layers 129a, 129b, and 129c, the first layer 113a, the second layer 113b, and the third layer 113c may cause a short circuit in the light-emitting device. However, in the display device of one embodiment of the present invention, the insulating layers 125 and 127 cover the side surfaces of the conductive layers 129a, 129b, and 129c, the first layer 113a, the second layer 113b, and the third layer 113c. 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.

[0386] Furthermore, since the insulating layers 125 and 127 are filled between the first layer 113a and the second layer 113b and between the second layer 113b and the third layer 113c, the surface on which the common electrode 115 is formed has smaller steps and is flatter than when the insulating layers 125 and 127 are not provided. This allows the coverage of the common electrode 115 to be improved.

[0387] [Example 2 of Manufacturing Method of Display Device] Next, an example of a manufacturing method of a display device will be described with reference to Fig. 15 and Fig. 16. Fig. 15A to Fig. 15C and Fig. 16 show a cross-sectional view taken along dashed dotted lines X1-X2 and Y1-Y2 in Fig. 1A side by side.

[0388] In Manufacturing Method Example 2, the steps shown in Figures 15 and 16 are performed after the step of forming conductive layers 129a, 129b, 129c, and 123c shown in Figure 11A. Note that detailed description of the same parts as in Manufacturing Method Example 1 may be omitted.

[0389] In the present manufacturing method example 2, the sacrificial layers 119a, 119b, and 119c are not removed, and an insulating film 125A is formed on the sacrificial layers 119a, 119b, and 119c (see FIG. 15A).

[0390] Next, as shown in FIG. 15B, an insulating layer 127 is formed on the insulating film 125A.

[0391] Next, as shown in FIG. 15C, at least a portion of the insulating film 125A, the sacrificial layers 119a, 119b, 119c, and the sacrificial layers 118a, 118b, 118c is removed to expose the first layer 113a, the second layer 113b, and the third layer 113c.

[0392] The sacrificial layers 119a, 119b, and 119c and the sacrificial layers 118a, 118b, and 118c may be removed in separate steps or in the same step. The sacrificial layers 118a, 118b, and 118c and the insulating film 125A may be removed in separate steps or in the same step. The sacrificial layers 119a, 119b, and 119c, the sacrificial layers 118a, 118b, and 118c, and the insulating film 125A may be removed all at once.

[0393] 15C, the region of insulating film 125A that overlaps with insulating layer 127 remains as insulating layer 125. Furthermore, the regions of sacrificial layers 119a, 119b, and 119c and sacrificial layers 118a, 118b, and 118c that overlap with insulating layer 127 also remain.

[0394] In this manner, the display device of one embodiment of the present invention may have a structure in which not only the first sacrificial layer but also the second sacrificial layer remains.

[0395] Then, as shown in FIG. 16, a fourth layer 114 can be formed on the first layer 113a, the second layer 113b, and the third layer 113c, and a common electrode 115 can be formed on the fourth layer 114.

[0396] [Example 3 of Manufacturing Method of Display Device] Next, an example of a manufacturing method of a display device will be described with reference to Fig. 17. Fig. 17A and Fig. 17B show a cross-sectional view taken along dashed dotted lines X1-X2 and Y1-Y2 in Fig. 1A side by side.

[0397] In this manufacturing method example 3, a manufacturing method will be described in which EL layers having the same configuration are formed in all sub-pixels.

[0398] For example, when a full-color display device is fabricated by combining a white-emitting light-emitting device with a color filter, or by combining a blue-emitting light-emitting device with a color conversion layer, it may be possible to apply EL layers of the same configuration to all sub-pixels.

[0399] First, the conductive layers 111a, 111b, and 111c to the conductive film 129 are formed in this order over the layer 101 including a transistor, similarly to Manufacturing Method Example 1. Then, as shown in FIG. 17A , the EL layer 113 is formed over the conductive film 129, a first sacrificial layer 118A is formed over the EL layer 113, and a second sacrificial layer 119A is formed over the first sacrificial layer 118A.

[0400] 17A, a resist mask 190 is formed on the second sacrificial layer 119A. The resist mask 190 is provided at a position that overlaps with each of the regions that will later become the sub-pixels 110a, 110b, and 110c.

[0401] Here, the resist mask 190 is preferably formed so that the edges of the resist mask 190 are located outside the edges of the conductive layers 126a, 126b, and 126c. This allows the edges of the conductive layer 129a and the first layer 113a to be formed later to be located outside the edge of the conductive layer 126a. Similarly, the edges of the conductive layer 129b and the second layer 113b to be formed later can be located outside the edge of the conductive layer 126b, and the edges of the conductive layer 129c and the third layer 113c to be formed later can be located outside the edge of the conductive layer 126c.

[0402] Then, similarly to Manufacturing Method Example 1, a sacrificial layer 119a is formed using a resist mask 190, and after removing the resist mask 190, a sacrificial layer 118a is formed using the sacrificial layer 119a as a mask. Then, parts of the EL layer 113 are removed using the sacrificial layers 119a and 118a as masks. As a result, as shown in FIG. 17B , the first layer 113a, the second layer 113b, and the third layer 113c can be formed. The first layer 113a, the second layer 113b, and the third layer 113c are formed by processing the EL layer 113, and therefore have the same structure.

[0403] In Manufacturing Method Example 1, the first layer 113a, the second layer 113b, and the third layer 113c are formed using different films, so the EL layer is processed three times using a resist mask. On the other hand, in Manufacturing Method Example 3, the first layer 113a, the second layer 113b, and the third layer 113c can be formed by processing the EL layer only once using a resist mask. This is preferable because it reduces the number of manufacturing steps.

[0404] 17B, ​​the process can proceed to the process shown in Fig. 11A or the process shown in Fig. 15A. Therefore, the following steps can be described with reference to the first and second fabrication methods.

[0405] 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.

[0406] The first, second, and third layers constituting the light-emitting device of each color are formed in separate processes. Therefore, each EL layer can be fabricated with a configuration (material, film thickness, etc.) suitable for the light-emitting device of each color. This allows the fabrication of light-emitting devices with excellent characteristics.

[0407] A display device according to one embodiment of the present invention includes an insulating layer covering each side surface of 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 insulating layer prevents the EL layer formed in an island shape from contacting the carrier injection layer or the common electrode, thereby preventing a short circuit of the light-emitting device.

[0408] 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.

[0409] Embodiment 2 In this embodiment, a structural example of a light-emitting device that can be applied to a display device of one embodiment of the present invention will be described with reference to FIGS.

[0410] The display device 500 shown in FIGS. 18A to 18C includes a light emitting device 550R that emits red light, a light emitting device 550G that emits green light, and a light emitting device 550B that emits blue light.

[0411] 18A and 18B includes a light-emitting unit 512R_1 between a pair of electrodes (electrode 501 and electrode 502). Similarly, a light-emitting device 550G includes a light-emitting unit 512G_1, and a light-emitting device 550B includes a light-emitting unit 512B_1.

[0412] That is, each of the light emitting devices 550R, 550G, and 550B shown in FIGS. 18A and 18B is a light emitting device having a single structure and including one light emitting unit.

[0413] 18C 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 a charge generation layer 531. Similarly, light-emitting device 550G has light-emitting units 512G_1 and 512G_2, and light-emitting device 550B has light-emitting units 512B_1 and 512B_2.

[0414] That is, each of the light emitting devices 550R, 550G, and 550B shown in FIG. 18C is a light emitting device having a tandem structure and including two light emitting units.

[0415] A configuration in which multiple light-emitting units are connected in series via a charge generation layer 531, such as light-emitting device 550R, light-emitting device 550G, and light-emitting device 550B shown in FIG. 18C, is referred to as a tandem structure in this specification. On the other hand, a configuration in which one light-emitting unit is located between a pair of electrodes, such as light-emitting devices 550R, 550G, and 550B shown in FIGS. 18A and 18B, is referred to as a single structure. Although the term "tandem structure" is used in this specification and the like, this is not limiting; for example, the tandem structure may also be referred to as a "stack structure." The tandem structure allows for 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.

[0416] Furthermore, a structure in which a separate light-emitting layer is formed for each light-emitting device, such as the display device 500 shown in FIGS. 18A to 18C, is sometimes called an SBS (Side By Side) structure.

[0417] The display device 500 shown in FIG. 18C has light-emitting devices with a tandem structure and can be considered to have an SBS structure. Therefore, it can combine the advantages of both a tandem structure and an SBS structure. The display device 500 shown in FIG. 18C may also be referred to as a two-tier tandem structure because the light-emitting units are formed in two tiers in series. The two-tier tandem structure of the light-emitting device 550R shown in FIG. 18C is structured such that a second light-emitting unit having a red light-emitting layer is stacked on top of a first light-emitting unit having a red light-emitting layer. Similarly, the two-tier tandem structure of the light-emitting device 550G shown in FIG. 18C is structured such that a second light-emitting unit having a green light-emitting layer is stacked on top of a first light-emitting unit having a green light-emitting layer. The two-tier tandem structure of the light-emitting device 550B is structured such that a second light-emitting unit having a blue light-emitting layer is stacked on top of a first light-emitting unit having a blue light-emitting layer.

[0418] The electrode 501 functions as a pixel electrode and is provided for each light-emitting device, while the electrode 502 functions as a common electrode and is provided in common to a plurality of light-emitting devices.

[0419] The light-emitting unit has at least one light-emitting layer. The light-emitting unit may have any number of light-emitting layers, and may have one, two, three, four or more light-emitting layers.

[0420] The light-emitting unit 512R_1 includes a layer 521, a layer 522, a light-emitting layer 523R, a layer 524, and the like. FIG. 18A shows an example in which the light-emitting unit 512R_1 includes a layer 525, and FIG. 18B shows an example in which the light-emitting unit 512R_1 does not include the layer 525, and the layer 525 is provided in common among the light-emitting devices. In this case, the layer 525 can be referred to as a common layer. By providing one or more common layers to the plurality of light-emitting devices in this way, the manufacturing process can be simplified, and therefore the manufacturing cost can be reduced.

[0421] The light-emitting unit 512R_2 includes a layer 522, a light-emitting layer 523R, a layer 524, and the like. Although the example in which the layer 525 is provided as a common layer is shown in Fig. 18C, the layer 525 may be provided for each light-emitting device. In other words, the layer 525 may be included in the light-emitting unit 512R_2.

[0422] The layer 521 includes, for example, a layer containing a substance with a high hole-injection property (hole-injection layer). The layer 522 includes, for example, a layer containing a substance with a high hole-transport property (hole-transport layer). The layer 524 includes, for example, a layer containing a substance with a high electron-transport property (electron-transport layer). The layer 525 includes, for example, a layer containing a substance with a high electron-injection property (electron-injection layer).

[0423] 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.

[0424] 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.

[0425] 18A and the like, the layer 521 and the layer 522 are separately illustrated, but this is not limiting. For example, when the layer 521 has a function of both a hole injection layer and a hole transport layer, or when the layer 521 has a function of both an electron injection layer and an electron transport layer, the layer 522 may be omitted.

[0426] The charge generation 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.

[0427] The light-emitting layer 523R of the light-emitting device 550R contains a light-emitting material that emits red light, the light-emitting layer 523G of the light-emitting device 550G contains a light-emitting material that emits green light, and the light-emitting layer 523B of the light-emitting device 550B contains a light-emitting material that emits blue light. The light-emitting devices 550G and 550B have a configuration in which the light-emitting layer 523R of the light-emitting device 550R is replaced with the light-emitting layer 523G and the light-emitting layer 523B, respectively, and are otherwise similar in configuration to the light-emitting device 550R.

[0428] 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.

[0429] 18A and 18B, the light-emitting unit 512R_1, the light-emitting unit 512G_1, and the light-emitting unit 512B_1 can be formed as island layers. That is, the EL layer 113 shown in FIG. 18A and 18B corresponds to the first layer 113a, the second layer 113b, or the third layer 113c shown in FIG. 1B and the like.

[0430] 18C , the light-emitting unit 512R_1, the charge generation layer 531, and the light-emitting unit 512R_2 can be formed as island layers. The light-emitting unit 512G_1, the charge generation layer 531, and the light-emitting unit 512G_2 can be formed as island layers. The light-emitting unit 512B_1, the charge generation layer 531, and the light-emitting unit 512B_2 can be formed as island layers. In other words, the EL layer 113 shown in FIG. 18C corresponds to the first layer 113a, the second layer 113b, or the third layer 113c shown in FIG. 1B and the like.

[0431] In Figures 18B and 18C, layer 525 corresponds to fourth layer 114 shown in Figure 1B.

[0432] 18C , the light-emitting layer 523R of the light-emitting unit 512R_1 contains a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 contains a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 contains a fluorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 contains a fluorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 contains a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 contains a fluorescent material.

[0433] Alternatively, in the display device 500 shown in FIG. 18C, 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.

[0434] 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.

[0435] 18C , 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 while the light-emitting units 512R_1 and 512R_2 have been described above, similar 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.

[0436] 19A and 19B includes a plurality of light-emitting devices 550W that emit white light. A colored layer 545R that transmits red light, a colored layer 545G that transmits green light, or a colored layer 545B that transmits blue light is provided on each of the light-emitting devices 550W. The colored layers 545R, 545G, and 545B are preferably provided on the light-emitting devices 550W via a protective layer 540.

[0437] A light-emitting device 550W shown in FIG. 19A has a light-emitting unit 512W between a pair of electrodes (electrode 501 and electrode 502).

[0438] That is, the light emitting device 550W shown in FIG. 19A is a light emitting device of a single structure having one light emitting unit.

[0439] The light-emitting unit 512W includes a layer 521, a layer 522, a light-emitting layer 523Q1, a light-emitting layer 523Q2, a light-emitting layer 523Q3, a layer 524, and the like. The light-emitting device 550W includes a layer 525 and the like between the light-emitting unit 512W and the electrode 502. Note that the layer 525 can also be considered as part of the light-emitting unit 512W.

[0440] 19A , by selecting light-emitting layers such that the light emitted from the light-emitting layer 523Q_1, the light-emitting layer 523Q_2, and the light-emitting layer 523Q_3 has a complementary color relationship, white light can be emitted from the light-emitting device 550W. Note that, although an example in which the light-emitting unit 512W has three light-emitting layers is shown here, the number of light-emitting layers is not limited, and the number may be, for example, two.

[0441] Note that the light-emitting device 550W shown in FIG. 19A has a structure in which the light-emitting layer 523R of the light-emitting device 550R shown in FIG. 18B is replaced with light-emitting layers 523Q_1 to 523Q_3, and the other structures are the same as those of the light-emitting device 550R.

[0442] A light-emitting device 550W shown in FIG. 19B has a configuration in which two light-emitting units (light-emitting unit 512Q_1 and light-emitting unit 512Q_2) are stacked between a pair of electrodes (electrode 501 and electrode 502) with a charge generation layer 531 interposed therebetween.

[0443] The light-emitting unit 512Q_1 includes a layer 521, a layer 522, a light-emitting layer 523Q_1, a layer 524, etc. The light-emitting unit 512Q_2 includes a layer 522, a light-emitting layer 523Q_2, a layer 524, etc. The light-emitting device 550W includes a layer 525 and the like between the light-emitting unit 512Q_2 and the electrode 502. Note that the layer 525 can also be considered as part of the light-emitting unit 512Q_2.

[0444] In the light-emitting device 550W shown in FIG. 19B , white light can be obtained from the light-emitting device 550W by selecting light-emitting layers such that the light emitted by the light-emitting layer 523Q_1 and the light-emitting layer 523Q_2 have a complementary color relationship. Note that, although an example is shown here in which the light-emitting units 512Q_1 and 512Q_2 each have one light-emitting layer, the number of light-emitting layers in each light-emitting unit is not critical. For example, the light-emitting units 512Q_1 and 512Q_2 may have different numbers of light-emitting layers. For example, one light-emitting unit may have two light-emitting layers, and the other light-emitting unit may have one light-emitting layer.

[0445] 19B has a configuration in which the light-emitting layer 523R of the light-emitting device 550R shown in FIG. 18C is replaced with a light-emitting layer 523Q_1, etc., and the other configuration is the same as that of the light-emitting device 550R.

[0446] The display device 500 shown in Figures 20 to 22 has a light-emitting device 550R that emits red light, a light-emitting device 550G that emits green light, a light-emitting device 550B that emits blue light, and a light-emitting device 550W that emits white light.

[0447] The display device shown in Figures 20A and 20B is an example in which a light-emitting device 550W that emits white light is provided in addition to the light-emitting devices 550R, 550G, and 550B shown in Figure 18B. The display device shown in Figure 21A is an example in which a light-emitting device 550W that emits white light is provided in addition to the light-emitting devices 550R, 550G, and 550B shown in Figure 18C.

[0448] The light-emitting device 550W shown in Figures 20A and 21A has a configuration in which two light-emitting units (light-emitting unit 512Q_1 and light-emitting unit 512Q_2) are stacked between a pair of electrodes (electrode 501 and electrode 502) with a charge generation layer 531 interposed therebetween.

[0449] The light-emitting device 550W shown in Figure 20B has a configuration in which three light-emitting units (light-emitting unit 512Q_1, light-emitting unit 512Q_2, and light-emitting unit 512Q_3) are stacked between a pair of electrodes (electrode 501 and electrode 502) with a charge generation layer 531 interposed between them.

[0450] The light-emitting unit 512Q_1 includes a layer 521, a layer 522, a light-emitting layer 523Q_1, a layer 524, etc. The light-emitting unit 512Q_2 includes a layer 522, a light-emitting layer 523Q_2, a layer 524, etc. The light-emitting unit 512Q_3 includes a layer 522, a light-emitting layer 523Q_3, a layer 524, etc.

[0451] In the light-emitting device 550W shown in FIGS. 20A and 21A, white light can be emitted from the light-emitting device 550W by selecting light-emitting layers 523Q_1 and 523Q_2 such that the light emitted from the light-emitting layers 523Q_1 and 523Q_2 has a complementary color relationship.

[0452] In the light-emitting device 550W shown in FIG. 20B, white light can be obtained from the light-emitting device 550W by selecting light-emitting layers 523Q_1, 523Q_2, and 523Q_3 such that the light emitted from these layers has a complementary color relationship.

[0453] The light-emitting device 550W has a configuration in which the light-emitting layer 523R of the light-emitting device 550R is replaced with a light-emitting layer 523Q_1 or the like, and the other configurations are the same as those of the light-emitting device 550R.

[0454] The display device 500 shown in FIG. 21B is an example in which a light-emitting device 550R emitting red light, a light-emitting device 550G emitting green light, a light-emitting device 550B emitting blue light, and a light-emitting device 550W emitting white light all have a three-tiered tandem structure in which three light-emitting units are stacked. In FIG. 21B , the light-emitting device 550R has a light-emitting unit 512R_3 stacked on top of a light-emitting unit 512R_2 with a charge generation layer 531 interposed therebetween. The light-emitting unit 512R_3 includes 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, the light-emitting unit 512B_3 included in the light-emitting device 550B, and the light-emitting unit 512Q_3 included in the light-emitting device 550W.

[0455] FIG. 22A shows an example in which a light emitting device 550W that emits white light is provided in addition to the light emitting devices 550R, 550G, and 550B shown in FIG. 18A.

[0456] 22A has a configuration in which n light-emitting units (n is an integer of 2 or more) are stacked between a pair of electrodes (electrode 501, electrode 502) via a charge generation layer 531. The light-emitting device 550W has n light-emitting units, light-emitting unit 512Q_1 to light-emitting unit 512Q_n, and the light from these light-emitting units has a complementary color relationship, so that the light can emit white light.

[0457] 22B , a light-emitting device 550R emitting red light, a light-emitting device 550G emitting green light, a light-emitting device 550B emitting blue light, and a light-emitting device 550W emitting white light all have a configuration in which n light-emitting units (n is an integer of 2 or more) are stacked. The light-emitting device 550R has n light-emitting units, light-emitting unit 512R_1 to light-emitting unit 512R_n, each having a light-emitting layer that emits red light. The light-emitting device 550G has n light-emitting units, light-emitting unit 512G_1 to light-emitting unit 512G_n, each having a light-emitting layer that emits green light. The light-emitting device 550B has n light-emitting units, light-emitting unit 512B_1 to light-emitting unit 512B_n, each having a light-emitting layer that emits blue light.

[0458] 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.

[0459] This embodiment mode can be combined with other embodiment modes as appropriate.

[0460] Embodiment 3 In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0461] The display device of the present embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of the present embodiment can be used in electronic devices having relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproducing devices.

[0462] [Display Device 100A] FIG. 23 shows a perspective view of the display device 100A, and FIG. 24A shows a cross-sectional view of the display device 100A.

[0463] The display device 100A has a configuration in which a substrate 152 and a substrate 151 are bonded together. In Fig. 23, the substrate 152 is clearly indicated by a dashed line.

[0464] The display device 100A includes a display portion 162, a connection portion 140, a circuit 164, wiring 165, and the like. Fig. 23 shows an example in which an IC 173 and an FPC 172 are mounted on the display device 100A. Therefore, the configuration shown in Fig. 23 can also be said to be a display module including the display device 100A, an IC (integrated circuit), and an FPC.

[0465] The connection portion 140 is provided on the outside of the display portion 162. The connection portion 140 can be provided along one side or multiple sides of the display portion 162. There may be one or multiple connection portions 140. FIG. 23 shows an example in which the connection portion 140 is provided so as to surround the four sides of the display portion. The connection portion 140 electrically connects the common electrode of the light-emitting device and the conductive layer, and can supply a potential to the common electrode.

[0466] The circuit 164 can be, for example, a scanning line driver circuit.

[0467] The wiring 165 has a function of supplying signals and power to the display portion 162 and the circuit 164. The signals and power are input to the wiring 165 from the outside via the FPC 172 or input to the wiring 165 from the IC 173.

[0468] 23 shows an example in which an IC 173 is provided on a substrate 151 by a chip-on-glass (COG) method or a chip-on-film (COF) method. The IC 173 may be, for example, an IC having a scanning line driver circuit or a signal line driver circuit. The display device 100A and the display module may not include an IC. Alternatively, the IC may be mounted on an FPC by a COF method or the like.

[0469] Figure 24A shows an example of a cross section of the display device 100A when cutting a portion of the area including the FPC 172, a portion of the circuit 164, a portion of the display unit 162, a portion of the connection portion 140, and a portion of the area including the end portion.

[0470] The display device 100A shown in Figure 24A has, between a substrate 151 and a substrate 152, a transistor 201, a transistor 205, a light-emitting device 130a that emits red light, a light-emitting device 130b that emits green light, and a light-emitting device 130c that emits blue light, etc.

[0471] 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.

[0472] The light-emitting devices 130a, 130b, and 130c each have the same structure as the stacked structure shown in Fig. 1B, except that the configuration of the pixel electrode is different. For details of the light-emitting devices, refer to Embodiment 1.

[0473] The light-emitting device 130a includes a conductive layer 111a, a conductive layer 112a on the conductive layer 111a, a conductive layer 126a on the conductive layer 112a, and a conductive layer 129a on the conductive layer 126a. All or some of the conductive layers 111a, 112a, 126a, and 129a may be called pixel electrodes.

[0474] The conductive layer 111a is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. An end of the conductive layer 112a is located outside an end of the conductive layer 111a. An end of the conductive layer 112a and an end of the conductive layer 126a are aligned or approximately aligned. An end of the conductive layer 129a is located outside an end of the conductive layers 112a and 126a. An end of the conductive layer 129a and an end of the first layer 113a are aligned or approximately aligned. For example, a conductive layer functioning as a reflective electrode can be used for the conductive layer 111a and the conductive layer 112a, and a conductive layer functioning as a transparent electrode can be used for the conductive layer 126a and the conductive layer 129a.

[0475] The conductive layers 111b, 112b, 126b, and 129b in the light-emitting device 130b and the conductive layers 111c, 112c, 126c, and 129c in the light-emitting device 130c are similar to the conductive layers 111a, 112a, 126a, and 129a in the light-emitting device 130a, and therefore will not be described in detail.

[0476] Recesses are formed in the conductive layers 111a, 111b, and 111c so as to cover the openings provided in the insulating layer 214. A layer 128 is buried in the recesses.

[0477] The layer 128 has a function of planarizing the recesses of the conductive layers 111a, 111b, and 111c. Conductive layers 112a, 112b, and 112c electrically connected to the conductive layers 111a, 111b, and 111c are provided on the conductive layers 111a, 111b, and 111c and the layer 128. Therefore, regions overlapping with the recesses of the conductive layers 111a, 111b, and 111c can also be used as light-emitting regions, thereby increasing the aperture ratio of the pixel.

[0478] The layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used as appropriate for the layer 128. In particular, the layer 128 is preferably formed using an insulating material.

[0479] An insulating layer containing an organic material can be suitably used as the layer 128. For example, acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, precursors of these resins, or the like can be used as the layer 128. Alternatively, a photosensitive resin can be used as the layer 128. The photosensitive resin can be a positive-type material or a negative-type material.

[0480] By using a photosensitive resin, the layer 128 can be formed only through exposure and development steps, and the influence of dry etching, wet etching, etc. on the surfaces of the conductive layers 111a, 111b, and 111c can be reduced. Furthermore, by forming the layer 128 using a negative photosensitive resin, the layer 128 can be formed using the same photomask (exposure mask) as that used to form the openings in the insulating layer 214 in some cases.

[0481] The top and side surfaces of the conductive layer 112a and the conductive layer 126a are covered with the conductive layer 129a and the first layer 113a. Similarly, the top and side surfaces of the conductive layer 112b and the conductive layer 126b are covered with the conductive layer 129b and the second layer 113b. The top and side surfaces of the conductive layer 112c and the conductive layer 126c are covered with the conductive layer 129c and the third layer 113c. Therefore, the entire regions where the conductive layers 112a, 112b, and 112c are provided can be used as light-emitting regions of the light-emitting devices 130a, 130b, and 130c, thereby increasing the aperture ratio of the pixel.

[0482] The side surfaces of the conductive layers 129a, 129b, and 129c, the first layer 113a, the second layer 113b, and the third layer 113c are covered with insulating layers 125 and 127, respectively. A sacrificial layer 118a is located between the first layer 113a and the insulating layer 125. A sacrificial layer 118b is located between the second layer 113b and the insulating layer 125, and a sacrificial layer 118c is located between the third layer 113c and the insulating layer 125. A fourth layer 114 is provided on the first layer 113a, the second layer 113b, the third layer 113c, and the insulating layers 125 and 127, and a common electrode 115 is provided on the fourth layer 114. A protective layer 131 is provided on each of the light-emitting devices 130a, 130b, and 130c.

[0483] The protective layer 131 and the substrate 152 are bonded via an adhesive layer 142. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light-emitting device. In FIG. 24A , the space between the substrates 152 and 151 is filled with the adhesive layer 142, and a solid sealing structure is applied. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), and a hollow sealing structure may be applied. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting device. Alternatively, the space may be filled with a resin different from the frame-shaped adhesive layer 142.

[0484] In the connection portion 140, a conductive layer 123 is provided on the insulating layer 214. The conductive layer 123 has an example of a stacked structure including a conductive film obtained by processing the same conductive film as the conductive layers 111a, 111b, and 111c, a conductive film obtained by processing the same conductive film as the conductive layers 112a, 112b, and 112c, a conductive film obtained by processing the same conductive film as the conductive layers 126a, 126b, and 126c, and a conductive film obtained by processing the same conductive film as the conductive layers 129a, 129b, and 129c. The end portions of the conductive layer 123 are covered with a sacrificial layer 118a, an insulating layer 125, and an insulating layer 127. A fourth layer 114 is provided on the conductive layer 123, and a common electrode 115 is provided on the fourth layer 114. The conductive layer 123 and the common electrode 115 are electrically connected to each other through the fourth layer 114. The fourth layer 114 does not necessarily have to be formed on the connection portion 140. In this case, the conductive layer 123 and the common electrode 115 are in direct contact with each other and electrically connected.

[0485] The display device 100A is a top-emission type. Light emitted by the light-emitting device is emitted toward the substrate 152. The substrate 152 is preferably made of a material that is highly transparent to visible light. The pixel electrodes contain a material that reflects visible light, and the counter electrode (common electrode 115) contains a material that transmits visible light.

[0486] The stacked structure from the substrate 151 to the insulating layer 214 corresponds to the layer 101 including the transistor in Embodiment 1.

[0487] The transistor 201 and the transistor 205 are both formed over a substrate 151. These transistors can be manufactured using the same material and through the same process.

[0488] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 151 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 is provided to cover the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0489] At least one insulating layer covering the transistor is preferably made of a material that is resistant to the diffusion of impurities such as water and hydrogen. This allows the insulating layer to function as a barrier layer. With this structure, it is possible to effectively prevent impurities from diffusing into the transistor from the outside, thereby improving the reliability of the display device.

[0490] It is preferable to use an inorganic insulating film for each of the insulating layers 211, 213, and 215. 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. Alternatively, 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.

[0491] An organic insulating film is suitable for the insulating layer 214, which functions as a planarization layer. Materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene-based resin, phenolic resin, and precursors of these resins. The insulating layer 214 may also have a laminated structure of an organic insulating film and an inorganic insulating film. The outermost layer of the insulating layer 214 preferably functions as an etching protection film. This can prevent recesses from being formed in the insulating layer 214 during processing of the conductive layer 111a, the conductive layer 112a, the conductive layer 126a, or the like. Alternatively, recesses may be formed in the insulating layer 214 during processing of the conductive layer 111a, the conductive layer 112a, the conductive layer 126a, or the like.

[0492] The transistor 201 and the transistor 205 each include a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as a source and a drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0493] 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.

[0494] The transistor 201 and the transistor 205 have a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates may be connected and the same signal may be supplied to drive the transistor. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential for controlling the threshold voltage to one of the two gates and a potential for driving to the other.

[0495] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor, a single-crystal semiconductor, and a semiconductor having crystallinity other than a 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 transistor characteristics.

[0496] 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 in which a channel formation region is formed using metal oxide (hereinafter referred to as an OS transistor). Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystal silicon).

[0497] 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.

[0498] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) for the semiconductor layer. Alternatively, it is preferable to use an oxide containing indium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc.

[0499] 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 a composition in which In:M:Zn=1:1:1 or thereabouts, a composition in which In:M:Zn=1:1:1.2 or thereabouts, a composition in which In:M:Zn=2:1:3 or thereabouts, a composition in which In:M:Zn=3:1:2 or thereabouts, a composition in which In:M:Zn=4:2:3 or thereabouts, a composition in which In:M:Zn=4:2:4.1 or thereabouts, a composition in which In:M:Zn=5:1:3 or thereabouts, a composition in which In:M:Zn=5:1:6 or thereabouts, a composition in which In:M:Zn=5:1:7 or thereabouts, a composition in which In:M:Zn=5:1:8 or thereabouts, a composition in which In:M:Zn=6:1:6 or thereabouts, and a composition in which In:M:Zn=5:2:5 or thereabouts. The term "nearby composition" includes a range of ±30% of the desired atomic ratio.

[0500] For example, when describing a composition having 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 having 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 more than 0.1 and 2 or less and Zn is 5 to 7. Furthermore, when describing a composition having 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 more than 0.1 and 2 or less and Zn is more than 0.1 and 2 or less.

[0501] The transistors included in the circuit 164 may have the same structure as or different from the transistors included in the display portion 162. The transistors included in the circuit 164 may all have the same structure or may have two or more types. Similarly, the transistors included in the display portion 162 may all have the same structure or may have two or more types.

[0502] 24B and 24C show other examples of transistor configurations.

[0503] The transistor 209 and the transistor 210 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a semiconductor layer 231 including a channel formation region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 functioning as a gate insulating layer, a conductive layer 223 functioning as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel formation region 231i. The insulating layer 225 is located at least between the conductive layer 223 and the channel formation region 231i. Furthermore, an insulating layer 218 covering the transistor may be provided.

[0504] 24B shows an example in which the insulating layer 225 covers the top surface and side surfaces of the semiconductor layer 231. The conductive layer 222a and the conductive layer 222b are connected to the low-resistance region 231n through openings provided in the insulating layer 225 and the insulating layer 215, respectively. One of the conductive layer 222a and the conductive layer 222b functions as a source, and the other functions as a drain.

[0505] 24C , the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231 but does not overlap with the low-resistance region 231n. For example, the insulating layer 225 is processed using the conductive layer 223 as a mask, thereby manufacturing the structure shown in FIG. 24C . In FIG. 24C , the insulating layer 215 is provided to cover the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and the conductive layer 222b are connected to the low-resistance region 231n through openings in the insulating layer 215.

[0506] A connection portion 204 is provided in a region of the substrate 151 where the substrate 152 does not overlap. In the connection portion 204, the wiring 165 is electrically connected to the FPC 172 via a conductive layer 166 and a connection layer 242. The conductive layer 166 has an example of a stacked structure including a conductive film obtained by processing the same conductive film as the conductive layers 111a, 111b, and 111c, a conductive film obtained by processing the same conductive film as the conductive layers 112a, 112b, and 112c, and a conductive film obtained by processing the same conductive film as the conductive layers 126a, 126b, and 126c. The conductive layer 166 is exposed on the top surface of the connection portion 204. This allows the connection portion 204 and the FPC 172 to be electrically connected via the connection layer 242.

[0507] A light-shielding layer 117 is preferably provided on the surface of the substrate 152 facing the substrate 151. The light-shielding layer 117 can be provided between adjacent light-emitting devices, on the connecting portion 140, on the circuit 164, and the like. Various optical members can be disposed on the outside of the substrate 152. 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 the substrate 152 may also be provided with an anti-static film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses the occurrence of scratches during use, an impact absorbing layer, and the like.

[0508] By providing the protective layer 131 that covers the light emitting device, it is possible to prevent impurities such as water from entering the light emitting device, thereby improving the reliability of the light emitting device.

[0509] The substrate 151 and the substrate 152 can each 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 151 and the substrate 152 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used for the substrate 151 or the substrate 152.

[0510] Substrates 151 and 152 may each 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. One or both of substrates 151 and 152 may be made of glass having a thickness sufficient to provide flexibility.

[0511] 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).

[0512] 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.

[0513] 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.

[0514] 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.

[0515] The adhesive layer 142 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.

[0516] The connection layer 242 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0517] 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.

[0518] 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 display devices, and conductive layers (conductive layers functioning as pixel electrodes or common electrodes) in light-emitting devices.

[0519] 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.

[0520] 25A is a bottom-emission type display device that combines a white light-emitting device and a color filter, and is different from the display device 100A. In the following description of the display device, descriptions of parts that are the same as those of the display devices described above may be omitted.

[0521] Light emitted from the light-emitting device is emitted toward the substrate 151. A material that is highly transparent to visible light is preferably used for the substrate 151. On the other hand, the light-transmitting property of the material used for the substrate 152 does not matter.

[0522] It is preferable to form a light-shielding layer 117 between the substrate 151 and the transistor 201 and between the substrate 151 and the transistor 205. Fig. 25A shows an example in which the light-shielding layer 117 is provided over the substrate 151, the insulating layer 153 is provided over the light-shielding layer 117, and the transistors 201, 205, and the like are provided over the insulating layer 153.

[0523] The light-emitting device 130a and the colored layer 132R overlap, and the light emitted from the light-emitting device 130a is extracted as red light to the outside of the display device 100B via the red colored layer 132R. Similarly, the light-emitting device 130b and the green colored layer 132G overlap, and the light emitted from the light-emitting device 130b is extracted as green light to the outside of the display device 100B via the colored layer 132G.

[0524] Both the light-emitting devices 130a and 130b can be configured to emit white light. That is, the first layer 113a and the second layer 113b can have the same structure. In FIG. 25A, the first layer 113a and the second layer 113b are illustrated as three layers. Specifically, a stacked structure of a first light-emitting unit, a charge generation layer, and a second light-emitting unit can be applied. The display device 100B can be manufactured using Example 3 of Manufacturing a Display Device, which is described in Embodiment 1.

[0525] 24A and 25A show examples in which the layer 128 has a flat portion on the upper surface, but there are no particular limitations on the shape of the layer 128. Modified examples of the layer 128 are shown in FIGS. 25B to 25D.

[0526] As shown in FIGS. 25B and 25D, the upper surface of layer 128 can be configured to have a recessed shape in the center and its vicinity in cross section, that is, a shape having a concave curved surface.

[0527] Furthermore, as shown in FIG. 25C, the upper surface of layer 128 can be configured to have a shape in which the center and its vicinity bulge in cross section, that is, a shape having a convex curve.

[0528] The upper surface of layer 128 may have one or both of a convex curved surface and a concave curved surface. The number of convex curved surfaces and the number of concave curved surfaces that the upper surface of layer 128 has are not limited, and may be one or more.

[0529] Furthermore, the height of the upper surface of layer 128 and the height of the upper surface of conductive layer 111a may be the same or approximately the same, or may be different from each other. For example, the height of the upper surface of layer 128 may be lower or higher than the height of the upper surface of conductive layer 111a.

[0530] 25B can also be considered an example in which layer 128 is contained within a recess formed in conductive layer 111a. On the other hand, as shown in Fig. 25D, layer 128 may be present outside the recess formed in conductive layer 111a, that is, the width of the top surface of layer 128 may be wider than the recess.

[0531] [Display Device 100C] A display device 100C shown in FIG. 26 differs from the display device 100A mainly in that a light-emitting device having a tandem structure is used.

[0532] In Figure 26, the first layer 113a, the second layer 113b, and the third layer 113c are each illustrated as three layers, and specifically, a stacked structure of a first light-emitting unit, a charge generation layer, and a second light-emitting unit can be applied.

[0533] 18C described in Embodiment 2 can be applied to the display device 100C. That is, the first layer 113a can have a structure in which 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, the second layer 113b can have a structure in which 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. Furthermore, the third layer 113c can have a structure in which 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.

[0534] By using light-emitting devices with a tandem structure, the brightness of the display device can be increased, or the current required to obtain the same brightness can be reduced, thereby improving the reliability of the display device.

[0535] [Display Device 100D] A display device 100D shown in FIG. 27 differs from the display device 100A mainly in that it includes a light receiving device 130d.

[0536] The light receiving device 130d has a conductive layer 111d, a conductive layer 112d on the conductive layer 111d, a conductive layer 126d on the conductive layer 112d, and a conductive layer 129d on the conductive layer 126d.

[0537] The conductive layer 111 d is connected to a conductive layer 222 b included in the transistor 205 through an opening provided in the insulating layer 214 .

[0538] The upper and side surfaces of the conductive layer 112d and the conductive layer 126d are covered with the conductive layer 129d and the fifth layer 113d. The fifth layer 113d includes at least an active layer.

[0539] The side surfaces of the conductive layer 129d and the fifth layer 113d are covered with insulating layers 125 and 127. A sacrificial layer 118d is located between the fifth layer 113d and the insulating layer 125. A fourth layer 114 is provided on the fifth layer 113d and the insulating layers 125 and 127, and a common electrode 115 is provided on the fourth layer 114. The fourth layer 114 is a continuous film provided in common to the light-receiving device and the light-emitting device.

[0540] 6A to 6D described in Embodiment 1 can be applied to the display device 100D. The light receiving device 130d can be provided in the subpixel PS or the subpixel IRS. For details of the display device having the light receiving device, refer to Embodiment 1.

[0541] This embodiment mode can be combined with other embodiment modes as appropriate.

[0542] Embodiment 4 In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0543] The display device of the present embodiment can be a high-definition display device, and therefore can be used as a display unit of a wearable device that can be worn on the head, such as a wristwatch-type or bracelet-type information terminal (wearable device), a head-mounted display or other VR device, or a glasses-type AR device.

[0544] 28A shows a perspective view of a display module 280. The display module 280 includes a display device 100E and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100E, and may be any of the display devices 100F to 100L described below.

[0545] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display portion 281. The display portion 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 portion 284 (described later) can be viewed.

[0546] 28B is a perspective view schematically illustrating the configuration on the substrate 291 side. A circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked on the substrate 291. A terminal portion 285 for connecting to the FPC 290 is provided in a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 composed of a plurality of wirings.

[0547] 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. 28B. The pixel 284a has light-emitting devices 130a, 130b, and 130c that emit light of different colors. The plurality of light-emitting devices can be arranged in a stripe array as shown in Fig. 28B. Various light-emitting device arrangement methods, such as a delta array or a pentile array, can also be applied.

[0548] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0549] 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 capacitor 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.

[0550] The circuit portion 282 includes a circuit for driving each pixel circuit 283 a of the pixel circuit portion 283. For example, the circuit portion 282 preferably 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.

[0551] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit portion 282. An IC may be mounted on the FPC 290.

[0552] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are provided overlapping below the pixel unit 284, 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 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 be 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 20,000 ppi or less, or 30,000 ppi or less.

[0553] Because such a display module 280 has extremely high resolution, it can be suitably used in VR devices such as head-mounted displays, or in glasses-type AR devices. For example, even in a configuration 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 even when the display unit is enlarged with 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 with relatively small display units. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0554] Display Device 100E A display device 100E shown in FIG. 29A includes a substrate 301, light-emitting devices 130a, 130b, and 130c, a capacitor 240, and a transistor 310. The display device 100E shown in FIG.

[0555] 28A and 28B. The stacked structure from the substrate 301 to the insulating layer 255b corresponds to the layer 101 including the transistor in Embodiment 1.

[0556] 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 one of a source and a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0557] An element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0558] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0559] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located therebetween. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as a dielectric of the capacitor 240.

[0560] 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.

[0561] An insulating layer 255a is provided to cover the capacitor 240, an insulating layer 255b is provided on the insulating layer 255a, and light-emitting devices 130a, 130b, 130c, etc. are provided on the insulating layer 255b. In this embodiment, an example is shown in which the light-emitting devices 130a, 130b, and 130c have a stacked structure similar to the stacked structure shown in FIG. 1B . Side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c are covered with insulating layers 125 and 127, respectively.

[0562] Furthermore, a sacrificial layer 118a is located on the first layer 113a. One end of the sacrificial layer 118a is flush or nearly flush with an end of the first layer 113a, and the other end of the sacrificial layer 118a is located on the first layer 113a. Similarly, one end of the sacrificial layer 118b on the second layer 113b is flush or nearly flush with an end of the second layer 113b. The other end of the sacrificial layer 118b is located on the second layer 113b. One end of the sacrificial layer 118c on the third layer 113c is flush or nearly flush with an end of the third layer 113c. The other end of the sacrificial layer 118c is located on the third layer 113c. A fourth layer 114 is provided on the first layer 113a, the second layer 113b, the third layer 113c, and the insulating layers 125 and 127, and a common electrode 115 is provided on the fourth layer 114. A protective layer 131 is provided on the light-emitting devices 130a, 130b, and 130c. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. 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. 28A .

[0563] The insulating layers 255a and 255b can be formed using various inorganic insulating films such as an insulating oxide film, an insulating nitride film, an oxynitride insulating film, and an insulating nitride oxide film. The insulating layer 255a is preferably formed using an oxide insulating film or an oxynitride insulating film such as a silicon oxide film, a silicon oxynitride film, or an aluminum oxide film. The insulating layer 255b is preferably formed using a nitride insulating film or a nitride oxide insulating film such as a silicon nitride film or a silicon nitride oxide film. More specifically, the insulating layer 255a is preferably formed using a silicon oxide film, and the insulating layer 255b is preferably formed using a silicon nitride film. The insulating layer 255b preferably functions as an etching protective film. Alternatively, the insulating layer 255a may be formed using a nitride insulating film or a nitride oxide insulating film, and the insulating layer 255b may be formed using an oxide insulating film or an oxynitride insulating film. Although this embodiment shows an example in which a recess is provided in the insulating layer 255b, the insulating layer 255b does not necessarily have a recess.

[0564] The pixel electrode of the light-emitting device is electrically connected to one of the source and drain of the transistor 310 via a plug 256 embedded in the insulating layers 255a and 255b, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. The height of the top surface of the insulating layer 255b and the height of the top surface of the plug 256 are the same or approximately the same. Various conductive materials can be used for the plug.

[0565] 29B is an example in which colored layers 132R, 132G, and 132B are provided on a protective layer 131. In the following description of the display device, descriptions of parts that are the same as those of the display devices described above may be omitted.

[0566] The light-emitting device 130a and the colored layer 132R overlap, and light emitted from the light-emitting device 130a is extracted as red light to the outside of the display device 100F via the red colored layer 132R. Similarly, the light-emitting device 130b and the green colored layer 132G overlap, and light emitted from the light-emitting device 130b is extracted as green light to the outside of the display device 100F via the colored layer 132G. The light-emitting device 130c and the blue colored layer 132B overlap, and light emitted from the light-emitting device 130c is extracted as blue light to the outside of the display device 100F via the colored layer 132B.

[0567] 29B shows an example in which the first layer 113a, the second layer 113b, and the third layer 113c have the same EL layer configuration. For example, the light-emitting devices 130a, 130b, and 130c can be configured to emit white light. Note that, as shown in FIG. 29A, the first layer 113a, the second layer 113b, and the third layer 113c may have different configurations.

[0568] The substrate 120 is bonded to the colored layers 132R, 132G, and 132B by a resin layer 122.

[0569] Display Device 100G The display device 100G shown in FIG. 29C is an example in which the substrate 120 provided with the colored layers 132R, 132G, and 132B is attached onto the protective layer 131 by the resin layer 122.

[0570] [Display Device 100H] A display device 100H shown in FIG. 30 differs from the display device 100E mainly in the configuration of the transistors.

[0571] 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.

[0572] 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 .

[0573] 28A and 28B . The stacked structure from the substrate 331 to the insulating layer 255b corresponds to the layer 101 including the transistor in Embodiment 1. The substrate 331 can be an insulating substrate or a semiconductor substrate.

[0574] 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.

[0575] 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.

[0576] 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.

[0577] The pair of conductive layers 325 are provided over and in contact with the semiconductor layer 321 and function as a source electrode and a drain electrode.

[0578] 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.

[0579] Openings reaching the semiconductor layer 321 are provided in the insulating layer 328 and the insulating layer 264. Inside the openings, an insulating layer 323 and a conductive layer 324 are buried, which are in contact with side surfaces of the insulating layer 264, the insulating layer 328, and the conductive layer 325 and an upper surface of the semiconductor layer 321. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0580] The top surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are the same or approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0581] 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.

[0582] 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 of 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.

[0583] The configuration of the display device 100H from the insulating layer 254 to the substrate 120 is the same as that of the display device 100E.

[0584] [Display Device 100J] A display device 100J illustrated in FIG. 31 has a stacked structure of a transistor 310 in which a channel is formed in a substrate 301 and a transistor 320 in which a channel is formed and a semiconductor layer containing metal oxide is formed.

[0585] 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 the 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.

[0586] The transistor 320 can be used as a transistor that forms a pixel circuit. The transistor 310 can be used as a transistor that forms a pixel circuit or a driver circuit (gate line driver circuit, source line driver circuit) that drives the pixel circuit. The transistors 310 and 320 can be used as transistors that form various circuits such as an arithmetic circuit or a memory circuit.

[0587] 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.

[0588] [Display Device 100K] A display device 100K shown in FIG. 32 has a stacked structure of a transistor 310A and a transistor 310B, each of which has a channel formed in a semiconductor substrate.

[0589] The display device 100K has a configuration in which a substrate 301B on which a transistor 310B, a capacitor 240, and each light-emitting device are provided and a substrate 301A on which a transistor 310A is provided are bonded together.

[0590] Here, it is preferable to provide an insulating layer 345 on the lower surface of the substrate 301B. It is also preferable to provide an insulating layer 346 on the insulating layer 261 provided on the substrate 301A. The insulating layers 345 and 346 are insulating layers that function as protective layers and can suppress the diffusion of impurities into the substrates 301B and 301A. The insulating layers 345 and 346 can be made of an inorganic insulating film that can be used for the protective layer 131 or the insulating layer 332.

[0591] The substrate 301B is provided with a plug 343 that penetrates the substrate 301B and an insulating layer 345. Here, it is preferable to provide an insulating layer 344 to cover the side surface of the plug 343. The insulating layer 344 is an insulating layer that functions as a protective layer and can suppress the diffusion of impurities into the substrate 301B. As the insulating layer 344, an inorganic insulating film that can be used for the protective layer 131 or the insulating layer 332 can be used.

[0592] Furthermore, a conductive layer 342 is provided on the back surface (surface opposite to the substrate 120 side) of the substrate 301B, below the insulating layer 345. The conductive layer 342 is preferably provided so as to be embedded in the insulating layer 335. Furthermore, the lower surfaces of the conductive layer 342 and the insulating layer 335 are preferably flattened. Here, the conductive layer 342 is electrically connected to the plug 343.

[0593] On the other hand, in the substrate 301A, a conductive layer 341 is provided on an insulating layer 346. The conductive layer 341 is preferably provided so as to be embedded in the insulating layer 336. In addition, the upper surfaces of the conductive layer 341 and the insulating layer 336 are preferably flattened.

[0594] The substrate 301A and the substrate 301B are electrically connected by bonding the conductive layer 341 and the conductive layer 342. Here, by improving the flatness of the surface formed by the conductive layer 342 and the insulating layer 335 and the surface formed by the conductive layer 341 and the insulating layer 336, the conductive layer 341 and the conductive layer 342 can be favorably bonded to each other.

[0595] It is preferable to use the same conductive material for the conductive layers 341 and 342. For example, a metal film containing an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, or a metal nitride film containing the above elements (titanium nitride film, molybdenum nitride film, tungsten nitride film), etc., can be used. In particular, it is preferable to use copper for the conductive layers 341 and 342. This allows the use of Cu-Cu (copper-copper) direct bonding technology (technology that achieves electrical conductivity by connecting Cu (copper) pads together).

[0596] 32 shows an example in which the Cu-Cu direct bonding technique is used to bond the conductive layer 341 and the conductive layer 342, but the present invention is not limited to this. As in the display device 100L shown in FIG. 33 , the conductive layer 341 and the conductive layer 342 may be bonded via a bump 347.

[0597] 33 , by providing a bump 347 between the conductive layer 341 and the conductive layer 342, the conductive layer 341 and the conductive layer 342 can be electrically connected. The bump 347 can be formed using a conductive material containing, for example, gold (Au), nickel (Ni), indium (In), tin (Sn), or the like. Alternatively, for example, solder may be used as the bump 347. An adhesive layer 348 may be provided between the insulating layer 345 and the insulating layer 346. When the bump 347 is provided, the insulating layer 335 and the insulating layer 336 may not be provided.

[0598] This embodiment mode can be combined with other embodiment modes as appropriate.

[0599] Embodiment 5 In this embodiment, a structural example of a transistor that can be applied to a display device of one embodiment of the present invention will be described. In particular, the case where a transistor containing silicon as a semiconductor in which a channel is formed will be described.

[0600] One embodiment of the present invention is a display device including a light-emitting device and a pixel circuit. The display device can achieve a full-color display device by including, for example, three types of light-emitting devices that emit red (R), green (G), and blue (B) light, respectively.

[0601] It is preferable that all transistors included in a pixel circuit that drives a light-emitting device be transistors having silicon in a semiconductor layer where a channel is formed. Examples of silicon include single crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, it is preferable to use a transistor having low temperature polysilicon (LTPS) in the semiconductor layer (hereinafter also referred to as an LTPS transistor). LTPS transistors have high field-effect mobility and good frequency characteristics.

[0602] By using silicon transistors such as LTPS transistors, circuits that need to be driven at high frequencies (such as source driver circuits) can be built on the same substrate as the display unit, which simplifies the external circuits mounted on the display device and reduces component and mounting costs.

[0603] At least one of the transistors included in the pixel circuit preferably includes a transistor (hereinafter also referred to as an OS transistor) having a metal oxide (hereinafter also referred to as an oxide semiconductor) as a semiconductor in which a channel is formed. The OS transistor has significantly higher field-effect mobility than an amorphous silicon transistor. Furthermore, the OS transistor has a significantly smaller source-drain leakage current in an off state (hereinafter also referred to as an off-state current), and can hold charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of an OS transistor can reduce the power consumption of a display device.

[0604] By using LTPS transistors for some of the transistors included in a pixel circuit and OS transistors for the other transistors, a display device with low power consumption and high driving capability can be realized. A configuration in which an LTPS transistor and an OS transistor are combined is sometimes referred to as LTPO. As a more preferred example, it is preferable to use an OS transistor as a transistor that functions as a switch for controlling conduction / non-conduction between wirings and to use an LTPS transistor as a transistor for controlling current.

[0605] For example, one of the transistors provided in the pixel circuit functions as a transistor for controlling a current flowing through a light-emitting device and can be called a driving transistor. One of the source and drain of the driving transistor is electrically connected to a pixel electrode of the light-emitting device. It is preferable to use an LTPS transistor as the driving transistor. This allows the current flowing through the light-emitting device in the pixel circuit to be increased.

[0606] On the other hand, another transistor provided in the pixel circuit functions as a switch for controlling pixel selection / non-selection and can also be called a selection transistor. The gate of the selection transistor is electrically connected to a gate line, and one of the source and drain is electrically connected to a source line (signal line). It is preferable to use an OS transistor as the selection transistor. This allows the gradation of a pixel to be maintained even when the frame frequency is significantly reduced (for example, 1 fps or less), and therefore power consumption can be reduced by stopping the driver when displaying a still image.

[0607] A more specific configuration example will be described below with reference to the drawings.

[0608] 34A shows a block diagram of the display device 10. The display device 10 includes a display unit 11, a drive circuit unit 12, a drive circuit unit 13, and the like.

[0609] The display unit 11 has a plurality of pixels 30 arranged in a matrix. Each pixel 30 has sub-pixels 21R, 21G, and 21B. Each of the sub-pixels 21R, 21G, and 21B has a light-emitting device that functions as a display device.

[0610] The pixel 30 is electrically connected to a wiring GL, a wiring SLR, a wiring SLG, and a wiring SLB. The wirings SLR, SLG, and SLB are each electrically connected to a driver circuit unit 12. The wiring GL is electrically connected to a driver circuit unit 13. The driver circuit unit 12 functions as a source line driver circuit (also referred to as a source driver), and the driver circuit unit 13 functions as a gate line driver circuit (also referred to as a gate driver). The wiring GL functions as a gate line, and the wirings SLR, SLG, and SLB function as source lines.

[0611] Sub-pixel 21R has a light-emitting device that emits red light. Sub-pixel 21G has a light-emitting device that emits green light. Sub-pixel 21B has a light-emitting device that emits blue light. This allows the display device 10 to display full color. Note that pixel 30 may also have sub-pixels that have light-emitting devices that emit light of other colors. For example, in addition to the above three sub-pixels, pixel 30 may also have a sub-pixel that has a light-emitting device that emits white light, or a sub-pixel that has a light-emitting device that emits yellow light, etc.

[0612] The wiring GL is electrically connected to the sub-pixels 21R, 21G, and 21B arranged in the row direction (extension direction of the wiring GL). The wiring SLR, wiring SLG, and wiring SLB are electrically connected to the sub-pixels 21R, 21G, and 21B (not shown) arranged in the column direction (extension direction of the wiring SLR, etc.), respectively.

[0613] [Configuration Example of Pixel Circuit] Figure 34B shows an example of a circuit diagram of a pixel 21 that can be applied to the subpixels 21R, 21G, and 21B. The pixel 21 includes a transistor M1, a transistor M2, a transistor M3, a capacitor C1, and a light-emitting device EL. A wiring GL and a wiring SL are electrically connected to the pixel 21. The wiring SL corresponds to any one of the wirings SLR, SLG, and SLB shown in Figure 34A.

[0614] The transistor M1 has a gate electrically connected to a wiring GL, one of a source and a drain electrically connected to a wiring SL, and the other electrically connected to one electrode of a capacitor C1 and the gate of the transistor M2. The transistor M2 has one of a source and a drain electrically connected to a wiring AL, and the other of a source and a drain electrically connected to one electrode of a light-emitting device EL, the other electrode of the capacitor C1, and one of a source and a drain of the transistor M3. The transistor M3 has a gate electrically connected to a wiring GL, and the other of a source and a drain electrically connected to a wiring RL. The light-emitting device EL has the other electrode electrically connected to a wiring CL.

[0615] A data potential is applied to the wiring SL. A selection signal is applied to the wiring GL. The selection signal includes a potential that turns on a transistor and a potential that turns off a transistor.

[0616] A reset potential is applied to the wiring RL. An anode potential is applied to the wiring AL. A cathode potential is applied to the wiring CL. In the pixel 21, the anode potential is higher than the cathode potential. The reset potential applied to the wiring RL can be a potential such that the potential difference between the reset potential and the cathode potential is smaller than the threshold voltage of the light-emitting device EL. The reset potential can be a potential higher than the cathode potential, the same as the cathode potential, or a potential lower than the cathode potential.

[0617] The transistors M1 and M3 function as switches. The transistor M2 functions as a transistor for controlling the current flowing through the light-emitting device EL. For example, it can be said that the transistor M1 functions as a selection transistor and the transistor M2 functions as a drive transistor.

[0618] Here, it is preferable that all of the transistors M1 to M3 be LTPS transistors. Alternatively, it is preferable that the transistors M1 and M3 be OS transistors and the transistor M2 be an LTPS transistor.

[0619] Alternatively, all of the transistors M1 to M3 may be OS transistors. In this case, one or more of the transistors included in the driver circuit portion 12 and the transistors included in the driver circuit portion 13 may be LTPS transistors, and the remaining transistors may be OS transistors. For example, OS transistors may be used as transistors provided in the display portion 11, and LTPS transistors may be used as transistors provided in the driver circuit portion 12 and the driver circuit portion 13.

[0620] As the OS transistor, a transistor including an oxide semiconductor for a semiconductor layer in which a channel is formed can be used. The semiconductor layer preferably contains, for example, indium, M (M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin. In particular, an oxide containing indium, gallium, and zinc (also referred to as IGZO) is preferably used for the semiconductor layer of the OS transistor. Alternatively, an oxide containing indium, tin, and zinc is preferably used. Alternatively, an oxide containing indium, gallium, tin, and zinc is preferably used.

[0621] A transistor using an oxide semiconductor, which has a wider band gap and a lower carrier concentration than silicon, can achieve an extremely small off-state current. Therefore, the small off-state current allows charge stored in a capacitor connected in series with the transistor to be held for a long period of time. Therefore, it is preferable to use transistors including oxide semiconductors for the transistors M1 and M3 connected in series with the capacitor C1. Using transistors including oxide semiconductors as the transistors M1 and M3 can prevent charge stored in the capacitor C1 from leaking through the transistor M1 or M3. Furthermore, because charge stored in the capacitor C1 can be held for a long period of time, a still image can be displayed for a long period of time without rewriting data in the pixel 21.

[0622] Note that although the transistors are shown as n-channel transistors in FIG. 34B, p-channel transistors can also be used.

[0623] Moreover, it is preferable that the transistors included in the pixel 21 are formed side by side on the same substrate.

[0624] As the transistor included in the pixel 21, a transistor having a pair of gates overlapping with each other with a semiconductor layer interposed therebetween can be used.

[0625] In a transistor having a pair of gates, when the pair of gates are electrically connected to each other and supplied with the same potential, the on-state current of the transistor is increased and the saturation characteristics are improved. A potential for controlling the threshold voltage of the transistor may be supplied to one of the pair of gates. Supplying a constant potential to one of the pair of gates can improve the stability of the electrical characteristics of the transistor. For example, one gate of the transistor may be electrically connected to a wiring to which a constant potential is supplied, or to its own source or drain.

[0626] 34C is an example of a pixel 21 in which the transistors M1 and M3 each have a pair of gates. The pair of gates of the transistors M1 and M3 are electrically connected. With this configuration, the period for writing data to the pixel 21 can be shortened.

[0627] 34D is an example in which a transistor having a pair of gates is used for the transistor M2 in addition to the transistors M1 and M3. The pair of gates of the transistor M2 are electrically connected. By using such a transistor for the transistor M2, the saturation characteristics are improved, which makes it easier to control the light emission luminance of the light-emitting device EL, thereby improving the display quality.

[0628] [Example of Transistor Structure] Hereinafter, an example of a cross-sectional structure of a transistor that can be applied to the display device will be described.

[0629] Configuration Example 1 FIG. 35A is a cross-sectional view including a transistor 410. FIG.

[0630] The transistor 410 is provided on the substrate 401 and has a semiconductor layer made of polycrystalline silicon. For example, the transistor 410 corresponds to the transistor M2 of the pixel 21. That is, Fig. 35A illustrates an example in which one of the source and drain of the transistor 410 is electrically connected to the conductive layer 431 of the light-emitting device.

[0631] The transistor 410 includes a semiconductor layer 411, an insulating layer 412, a conductive layer 413, and the like. The semiconductor layer 411 includes a channel formation region 411i and a low-resistance region 411n. The semiconductor layer 411 includes silicon. The semiconductor layer 411 preferably includes polycrystalline silicon. A part of the insulating layer 412 functions as a gate insulating layer. A part of the conductive layer 413 functions as a gate electrode.

[0632] Note that the semiconductor layer 411 can also include a metal oxide (also referred to as an oxide semiconductor) that exhibits semiconductor characteristics. In this case, the transistor 410 can be called an OS transistor.

[0633] The low-resistance region 411n is a region containing an impurity element. For example, when the transistor 410 is an n-channel transistor, phosphorus, arsenic, or the like may be added to the low-resistance region 411n. On the other hand, when the transistor 410 is a p-channel transistor, boron, aluminum, or the like may be added to the low-resistance region 411n. Furthermore, in order to control the threshold voltage of the transistor 410, the above-mentioned impurities may be added to the channel formation region 411i.

[0634] An insulating layer 421 is provided over a substrate 401. A semiconductor layer 411 is provided over the insulating layer 421. An insulating layer 412 is provided to cover the semiconductor layer 411 and the insulating layer 421. A conductive layer 413 is provided over the insulating layer 412 so as to overlap with the semiconductor layer 411.

[0635] An insulating layer 422 is provided to cover the conductive layer 413 and the insulating layer 412. A conductive layer 414a and a conductive layer 414b are provided over the insulating layer 422. The conductive layer 414a and the conductive layer 414b are electrically connected to the low-resistance region 411n through openings provided in the insulating layer 422 and the insulating layer 412. A part of the conductive layer 414a functions as one of the source electrode and the drain electrode, and a part of the conductive layer 414b functions as the other of the source electrode and the drain electrode. An insulating layer 423 is provided to cover the conductive layer 414a, the conductive layer 414b, and the insulating layer 422.

[0636] A conductive layer 431 functioning as a pixel electrode is provided over the insulating layer 423. The conductive layer 431 is provided over the insulating layer 423 and is electrically connected to the conductive layer 414b in an opening provided in the insulating layer 423. Although not shown here, an EL layer and a common electrode can be stacked over the conductive layer 431.

[0637] 35B shows a transistor 410a having a pair of gate electrodes, which is different from the transistor 410a shown in FIG. 35A in that a conductive layer 415 and an insulating layer 416 are included.

[0638] The conductive layer 415 is provided over the insulating layer 421. An insulating layer 416 is provided to cover the conductive layer 415 and the insulating layer 421. The semiconductor layer 411 is provided so that at least a channel formation region 411i overlaps with the conductive layer 415 with the insulating layer 416 interposed therebetween.

[0639] 35B, part of the conductive layer 413 functions as a first gate electrode, part of the conductive layer 415 functions as a second gate electrode, part of the insulating layer 412 functions as a first gate insulating layer, and part of the insulating layer 416 functions as a second gate insulating layer.

[0640] Here, when the first gate electrode and the second gate electrode are electrically connected, the conductive layer 413 and the conductive layer 415 may be electrically connected through openings provided in the insulating layers 412 and 416 in a region not shown. When the second gate electrode and the source or drain are electrically connected, the conductive layer 414a or the conductive layer 414b may be electrically connected to the conductive layer 415 through openings provided in the insulating layers 422, 412, and 416 in a region not shown.

[0641] 35A or 35B can be applied to all of the transistors constituting the pixel 21. In this case, the transistor 410a may be used for all of the transistors constituting the pixel 21, the transistor 410 may be used for all of the transistors constituting the pixel 21, or the transistor 410 may be used for all of the transistors, or the transistor 410a and the transistor 410 may be used in combination.

[0642] [Structure Example 3] Hereinafter, a structure example including both a transistor in which silicon is used for a semiconductor layer and a transistor in which a metal oxide is used for a semiconductor layer will be described.

[0643] FIG. 35C shows a cross-sectional schematic diagram including transistor 410a and transistor 450.

[0644] The transistor 410a can be configured as in the above-described Structure Example 1. Note that although the example using the transistor 410a is shown here, a structure including the transistor 410 and the transistor 450 may be used, or a structure including all of the transistor 410, the transistor 410a, and the transistor 450 may be used.

[0645] The transistor 450 is a transistor in which a metal oxide is used for a semiconductor layer. The configuration shown in Fig. 35C is an example in which the transistor 450 corresponds to the transistor M1 of the pixel 21 and the transistor 410a corresponds to the transistor M2. That is, Fig. 35C shows an example in which one of the source and the drain of the transistor 410a is electrically connected to the conductive layer 431.

[0646] FIG. 35C shows an example in which the transistor 450 has a pair of gates.

[0647] The transistor 450 includes a conductive layer 455, an insulating layer 422, a semiconductor layer 451, an insulating layer 452, a conductive layer 453, and the like. Part of the conductive layer 453 functions as a first gate of the transistor 450, and part of the conductive layer 455 functions as a second gate of the transistor 450. In this case, part of the insulating layer 452 functions as a first gate insulating layer of the transistor 450, and part of the insulating layer 422 functions as a second gate insulating layer of the transistor 450.

[0648] The conductive layer 455 is provided over the insulating layer 412. The insulating layer 422 is provided to cover the conductive layer 455. The semiconductor layer 451 is provided over the insulating layer 422. The insulating layer 452 is provided to cover the semiconductor layer 451 and the insulating layer 422. The conductive layer 453 is provided over the insulating layer 452 and has a region overlapping with the semiconductor layer 451 and the conductive layer 455.

[0649] An insulating layer 426 is provided to cover the insulating layer 452 and the conductive layer 453. A conductive layer 454a and a conductive layer 454b are provided over the insulating layer 426. The conductive layer 454a and the conductive layer 454b are electrically connected to the semiconductor layer 451 through openings provided in the insulating layer 426 and the insulating layer 452. A part of the conductive layer 454a functions as one of the source electrode and the drain electrode, and a part of the conductive layer 454b functions as the other of the source electrode and the drain electrode. An insulating layer 423 is provided to cover the conductive layer 454a, the conductive layer 454b, and the insulating layer 426.

[0650] Here, the conductive layers 414a and 414b electrically connected to the transistor 410a are preferably formed by processing the same conductive film as the conductive layers 454a and 454b. Figure 35C shows a configuration in which the conductive layers 414a, 414b, 454a, and 454b are formed on the same surface (i.e., in contact with the top surface of the insulating layer 426) and contain the same metal element. In this case, the conductive layers 414a and 414b are electrically connected to the low-resistance region 411n through openings provided in the insulating layer 426, the insulating layer 452, the insulating layer 422, and the insulating layer 412. This is preferable because it simplifies the manufacturing process.

[0651] The conductive layer 413 functioning as the first gate electrode of the transistor 410a and the conductive layer 455 functioning as the second gate electrode of the transistor 450 are preferably formed by processing the same conductive film. In Figure 35C, the conductive layer 413 and the conductive layer 455 are formed on the same surface (i.e., in contact with the top surface of the insulating layer 412) and contain the same metal element. This is preferable because it simplifies the manufacturing process.

[0652] In Figure 35C, the insulating layer 452 functioning as the first gate insulating layer of the transistor 450 covers the end portion of the semiconductor layer 451. However, as in the transistor 450a shown in Figure 35D, the insulating layer 452 may be processed so that the top surface shape thereof matches or approximately matches the top surface shape of the conductive layer 453.

[0653] In this specification, the phrase "top surface shapes generally match" refers to the overlap of at least a portion of the contours between stacked layers. For example, this includes cases where the upper and lower layers are processed using the same mask pattern or a portion of the same mask pattern. However, strictly speaking, the contours may not overlap, and the upper layer may be located inside the lower layer, or outside the lower layer. In these cases, the phrase "top surface shapes generally match" also applies.

[0654] Although the transistor 410a corresponds to the transistor M2 and is electrically connected to the pixel electrode in this example, the present invention is not limited to this. For example, the transistor 450 or the transistor 450a may correspond to the transistor M2. In this case, the transistor 410a corresponds to the transistor M1, the transistor M3, or another transistor.

[0655] This embodiment mode can be combined with other embodiment modes as appropriate.

[0656] Embodiment 6 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.

[0657] 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.

[0658] 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.

[0659] <Classification of Crystal Structure> Examples of the crystal structure of an oxide semiconductor include amorphous (including completely amorphous), c-axis-aligned crystalline line (CAAC), nanocrystalline line (nc), cloud-aligned composite (CAC), single crystal, and polycrystalline.

[0660] The crystalline structure of the film or substrate can be evaluated using an X-ray diffraction (XRD) spectrum. For example, it can be evaluated using an XRD spectrum obtained by a GIXD (Grazing-Incident XRD) measurement. The GIXD method is also called the thin film method or the Seemann-Bohlin method.

[0661] For example, in the case of a quartz glass substrate, the shape of the peak in the XRD spectrum is almost symmetrical. On the other hand, in the case of an IGZO film having a crystalline structure, the shape of the peak in the XRD spectrum is asymmetrical. The asymmetrical shape of the peak in the XRD spectrum clearly indicates the presence of crystals in the film or substrate. In other words, if the shape of the peak in the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0662] The crystalline structure of the film or substrate can be evaluated by a diffraction pattern (also referred to as a nanobeam electron diffraction pattern) observed by nanobeam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, and it can be confirmed that the quartz glass is in an amorphous state. Furthermore, a spot-like pattern is observed in the diffraction pattern of an IGZO film formed at room temperature, rather than a halo. For this reason, it is estimated that the IGZO film formed 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.

[0663] <<Structure of Oxide Semiconductor>> Note that oxide semiconductors may be classified differently from the above when focusing on their structures. For example, oxide semiconductors are classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, pseudo-amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0664] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0665] [CAAC-OS] A CAAC-OS is an oxide semiconductor having multiple crystalline regions, each with its c-axis aligned in a specific direction. The specific direction refers to the thickness direction of the CAAC-OS film, the normal direction to the surface where the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region having periodic atomic arrangement. If the atomic arrangement is considered as a lattice arrangement, a crystalline region is also a region with a uniform lattice arrangement. Furthermore, a CAAC-OS has a region where multiple crystalline regions are connected in the a-b plane direction, and the region may have distortion. Note that distortion refers to a portion where the lattice arrangement changes between a region with a uniform lattice arrangement and a region with another uniform lattice arrangement in a region where multiple crystalline regions are connected. In other words, a CAAC-OS is an oxide semiconductor whose c-axes are aligned and whose orientation is not clearly aligned in the a-b plane direction.

[0666] 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 a single minute crystal, the maximum diameter of the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of the crystalline region may be several tens of nanometers.

[0667] In an In-M-Zn oxide (wherein the element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, and the like), 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 the element 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 the element 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.

[0668] When a CAAC-OS film is subjected to structural analysis using an XRD apparatus, for example, a peak indicating c-axis orientation is detected at or near 2θ = 31° in out-of-plane XRD measurement using θ / 2θ scanning. Note that the position of the peak indicating c-axis orientation (the value of 2θ) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0669] For example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film, and the spots are observed at positions that are point-symmetric with respect to a spot of an incident electron beam that has passed through the sample (also referred to as a direct spot).

[0670] When a crystalline region is observed from the specific direction, the lattice arrangement in the crystalline region is basically a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be a non-regular hexagon. The distortion may have a pentagonal, heptagonal, or other lattice arrangement. In the CAAC-OS, no clear grain boundary can be identified even near the distortion. This indicates that the distortion in the lattice arrangement suppresses the formation of grain boundaries. This is thought to be because the CAAC-OS can tolerate distortion due to the lack of close-packed arrangement of oxygen atoms in the a-b plane and the change in interatomic bond distance caused by metal atom substitution.

[0671] Note that a crystal structure in which clear grain boundaries are observed is called polycrystalline. The grain boundaries act as recombination centers, and are likely to trap carriers, resulting in a decrease in the on-state current of a transistor and a decrease in field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries are not observed, is one of the crystalline oxides having a crystal structure suitable for a semiconductor layer of a transistor. Note that a structure containing Zn is preferable for forming a CAAC-OS. For example, In—Zn oxide and In—Ga—Zn oxide are suitable because they can suppress the generation of grain boundaries more effectively than In oxide.

[0672] CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to crystal grain boundaries. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by the inclusion of impurities, the formation of defects, or the like, the CAAC-OS can also be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Therefore, an oxide semiconductor having a CAAC-OS has stable physical properties. Therefore, an oxide semiconductor having a CAAC-OS is heat-resistant and highly reliable. Furthermore, the CAAC-OS is stable even against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, the use of a CAAC-OS in an OS transistor can increase the flexibility of the manufacturing process.

[0673] [nc-OS] The nc-OS has periodic atomic arrangement in a microscopic region (e.g., a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has microcrystals. Note that the size of the microcrystals is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore the microcrystals are also called nanocrystals. Furthermore, the nc-OS does not exhibit regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the fil...

Claims

1. a first light emitting device and a second light emitting device; the first light emitting device having a first conductive layer, a second conductive layer on the first conductive layer, a first light emitting layer on the second conductive layer, and a common electrode on the first light emitting layer; the second light emitting device has a third conductive layer, a fourth conductive layer on the third conductive layer, a second light emitting layer on the fourth conductive layer, and the common electrode on the second light emitting layer; the second conductive layer covers a side surface of the first conductive layer; the fourth conductive layer covers a side surface of the third conductive layer; an edge of the first light-emitting layer is aligned or approximately aligned with an edge of the second conductive layer; An edge of the second light-emitting layer is aligned or approximately aligned with an edge of the fourth conductive layer.

2. In claim 1, A first insulating layer is provided. the first insulating layer covers each side surface of the first light emitting layer, the second light emitting layer, the second conductive layer, and the fourth conductive layer; The common electrode is located on the first insulating layer.

3. In claim 2, A second insulating layer is provided. the first insulating layer comprises an inorganic material; The second insulating layer includes an organic material and overlaps with each side surface of the first light-emitting layer and the second light-emitting layer via the first insulating layer.

4. In claim 2 or 3, A first layer, the first layer is located on the first light-emitting layer; In a cross-sectional view, one end of the first layer is aligned or approximately aligned with an end of the first light-emitting layer and an end of the second conductive layer; the other end of the first layer is located on the first light-emitting layer in a cross-sectional view; The first insulating layer covers an upper surface of the first layer.

5. In claim 4, The display device, wherein the first layer has a laminated structure of an inorganic insulating layer and a conductive layer on the inorganic insulating layer.

6. In any one of claims 1 to 5, the first light-emitting device has a common layer between the first light-emitting layer and the common electrode; the second light-emitting device has the common layer between the second light-emitting layer and the common electrode; The display device, wherein the common layer has at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

7. a first light emitting device and a second light emitting device; the first light emitting device has a first conductive layer, a second conductive layer on the first conductive layer, a first EL layer on the second conductive layer, and a common electrode on the first EL layer; the second light emitting device has a third conductive layer, a fourth conductive layer on the third conductive layer, a second EL layer on the fourth conductive layer, and the common electrode on the second EL layer; the first EL layer has a first light-emitting unit on the second conductive layer, a first charge generating layer on the first light-emitting unit, and a second light-emitting unit on the first charge generating layer; the second EL layer has a third light-emitting unit on the fourth conductive layer, a second charge generating layer on the third light-emitting unit, and a fourth light-emitting unit on the second charge generating layer; the second conductive layer covers a side surface of the first conductive layer; the fourth conductive layer covers a side surface of the third conductive layer; an edge of the first EL layer is aligned or approximately aligned with an edge of the second conductive layer; An edge of the second EL layer is aligned or approximately aligned with an edge of the fourth conductive layer.

8. In claim 7, A first insulating layer is provided. the first insulating layer covers each side surface of the first EL layer, the second EL layer, the second conductive layer, and the fourth conductive layer; The common electrode is located on the first insulating layer.

9. In claim 8, A second insulating layer is provided. the first insulating layer comprises an inorganic material; The second insulating layer includes an organic material and overlaps with each side of the first EL layer and the second EL layer via the first insulating layer.

10. In claim 8 or 9, A first layer, the first layer is located on the first EL layer; In a cross-sectional view, one end of the first layer is aligned or approximately aligned with an end of the first EL layer and an end of the second conductive layer, and the other end of the first layer is located on the first EL layer; The first insulating layer covers an upper surface of the first layer.

11. In claim 10, The display device, wherein the first layer has a laminated structure of an inorganic insulating layer and a conductive layer on the inorganic insulating layer.

12. In any one of claims 7 to 11, the first light emitting device has a common layer between the first EL layer and the common electrode; the second light emitting device has the common layer between the second EL layer and the common electrode; The display device, wherein the common layer has at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

13. A display device according to any one of claims 1 to 12, A display module having at least one of a connector and an integrated circuit.

14. A display module according to claim 13; An electronic device having at least one of a housing, a battery, a camera, a speaker, and a microphone.

15. forming a first conductive layer and a second conductive layer in an island shape on an insulating surface; forming a first conductive film on the first conductive layer and the second conductive layer; forming a first layer on the first conductive film; forming a first sacrificial layer on the first layer; processing the first layer and the first sacrificial layer so that an end of the first layer and an end of the first sacrificial layer are positioned outside an end of the first conductive layer and at least a part of a region of the first conductive film overlapping with the second conductive layer is exposed; forming a second layer on the first sacrificial layer and on the first conductive film; forming a second sacrificial layer on the second layer; processing the second layer and the second sacrificial layer so that an end of the second layer and an end of the second sacrificial layer are located outside an end of the second conductive layer and at least a portion of the first sacrificial layer is exposed; forming a third conductive layer between the first conductive layer and the first layer and a fourth conductive layer between the second conductive layer and the second layer by processing the first conductive film using the first sacrificial layer and the second sacrificial layer as a hard mask; removing at least a portion of the first sacrificial layer and the second sacrificial layer to expose at least a portion of the first layer and the second layer; A method for manufacturing a display device, comprising forming a common electrode over the first layer and the second layer.

16. In claim 15, After forming the third conductive layer and the fourth conductive layer, and before forming the common electrode, forming a first insulating film covering at least a side surface of the third conductive layer, a side surface of the fourth conductive layer, a side surface of the first layer, a side surface of the second layer, a side surface and a top surface of the first sacrificial layer, and a side surface and a top surface of the second sacrificial layer; A method for manufacturing a display device, comprising: processing the first insulating film to form a first insulating layer having one end located on the first layer and the other end located on the second layer in a cross-sectional view.

17. In claim 16, forming the first insulating film using an inorganic material; After forming the first insulating film, a second insulating film is formed on the first insulating film by using an organic material; A method for manufacturing a display device, comprising: processing the second insulating film to form a second insulating layer having one end located on the first layer and the other end located on the second layer in a cross-sectional view.

18. In claim 17, A method for manufacturing a display device, wherein a photosensitive resin is used as the organic material.

19. In any one of claims 15 to 18, A method for manufacturing a display device, in a step of removing at least a portion of the first sacrificial layer, the first sacrificial layer is processed so that, in a cross-sectional view, one end is aligned or approximately aligned with an end of the first layer and the other end is located on the first layer.

20. In any one of claims 15 to 19, A method for manufacturing a display device, comprising forming at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer as a common layer on the first layer and the second layer before forming the common electrode.