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

Abstract

Provided is a display apparatus exhibiting high definition or high resolution. This display apparatus has a first light emitting device, a second light emitting device, a first insulation layer, and a first layer. The first light emitting device has a first pixel electrode, a first light emitting layer on the first pixel electrode, and a common electrode on the first light emitting layer. The second light emitting device has a second pixel electrode, a second light emitting layer on the second pixel electrode, and a common electrode on the second light emitting layer. The first light emitting layer covers a side surface of the first pixel electrode. The second light emitting layer covers a side surface of the second pixel electrode. 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 substantially aligned with an end of the first light emitting layer. Another end of the first layer is located on the first light emitting layer. The first insulation layer covers an upper surface of the first layer and a side surface of each of the first light emitting layer and the second light emitting layer. The common electrode is located on the first insulation layer.

Description

[Technical Field]

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

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

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

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

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

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

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

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

[0010] Furthermore, when manufacturing display devices using vacuum deposition with a metal mask, the metal mask needs to be cleaned periodically, which halts the process. Therefore, it is desirable to prepare at least two or more manufacturing lines, and to use one manufacturing line while the other is being maintained. Considering mass production, multiple manufacturing lines are necessary. Consequently, there is a challenge in that the initial investment required to introduce the manufacturing equipment is very large.

[0011] One aspect of the present invention aims to provide a high-definition display device. One aspect of the present invention aims to provide a high-resolution display device. One aspect of the present invention aims to provide a large-screen display device. One aspect of the present invention aims to provide a small-screen display device. One aspect of the present invention aims to provide a highly reliable display device.

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

[0013] Furthermore, the description of these problems does not preclude the existence of other problems. One aspect of the present invention does not necessarily have to solve all of these problems. It is possible to extract other problems from the description in the specification, drawings, and claims. [Means for solving the problem]

[0014] One aspect of the present invention comprises a first light-emitting device, a second light-emitting device, a first insulating layer, and a first layer, wherein the first light-emitting device comprises a first pixel electrode, a first light-emitting layer on the first pixel electrode, and a common electrode on the first light-emitting layer, and the second light-emitting device comprises a second pixel electrode, a second light-emitting layer on the second pixel electrode, and a common electrode on the second light-emitting layer, wherein the first light-emitting layer covers the side surface of the first pixel electrode, and the second The display device comprises a light-emitting layer covering the side surface of the second pixel electrode, a first layer located on the first light-emitting layer, where in cross-sectional view, one end of the first layer is aligned with or approximately aligned with the end of the first light-emitting layer, the other end of the first layer is located on the first light-emitting layer, a first insulating layer covering the top surface of the first layer and the respective side surfaces of the first and second light-emitting layers, and a common electrode located on the first insulating layer.

[0015] 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 it is preferable that the common layer has at least one 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.

[0016] The above-described display device preferably has a second insulating layer. The first insulating layer is made of an inorganic material, and the second insulating layer is made of an organic material, and preferably overlaps with the respective sides of the first light-emitting layer and the second light-emitting layer via the first insulating layer.

[0017] One aspect of the present invention comprises a first light-emitting device, a second light-emitting device, a first insulating layer, and a first layer, wherein the first light-emitting device comprises a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer, the second light-emitting device comprises a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer, the first EL layer comprises a first light-emitting unit on the first pixel electrode, a first charge generation layer on the first light-emitting unit, and a second light-emitting unit on the first charge generation layer, and the second EL layer comprises a third light-emitting unit on the second pixel electrode The display device comprises a light-emitting element, a second charge generation layer on a third light-emitting unit, and a fourth light-emitting unit on the second charge generation layer, wherein the first EL layer covers the side surface of the first pixel electrode, the second EL layer covers the side surface of the second pixel electrode, the first layer is located on the first EL layer, and in cross-sectional view, one end of the first layer is aligned with or approximately aligned with the end of the first EL layer, the other end of the first layer is located on the first EL layer, the first insulating layer covers the top surface of the first layer and the respective side surfaces of the first EL layer and the second EL layer, and the common electrode is located on the first insulating layer.

[0018] 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 it is preferable that the common layer has at least one 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.

[0019] The above-described display device preferably has a second insulating layer. The first insulating layer is made of an inorganic material, and the second insulating layer is made of an organic material, and preferably overlaps with the sides of the first EL layer and the second EL layer via the first insulating layer.

[0020] The first layer preferably has a laminated structure comprising an inorganic insulating layer and a conductive layer on the inorganic insulating layer.

[0021] The first pixel electrode has a first conductive layer and a second conductive layer on the first conductive layer, and it is preferable that the second conductive layer covers the side surface of the first conductive layer.

[0022] One aspect of the present invention is a display module having a display device with any of the above configurations, to which a connector such as a Flexible Printed Circuit (FPC) or TCP (Tape Carrier Package) is attached, or a display module on which an integrated circuit (IC) is mounted by a COG (Chip On Glass) method or a COF (Chip On Film) method, etc.

[0023] One aspect of the present invention is an electronic device having the above-mentioned display module and at least one of a housing, a battery, a camera, a speaker, and a microphone.

[0024] One aspect of the present invention involves forming a first pixel electrode and a second pixel electrode on an insulating surface, forming a first layer on the first pixel electrode and the second pixel electrode, forming a first sacrificial layer on the first layer, processing the first layer and the first sacrificial layer such that the edges of the first layer and the edges of the first sacrificial layer are located outside the edges of the first pixel electrode and at least a portion of the second pixel electrode is exposed, forming a second layer on the first sacrificial layer and the second pixel electrode, forming a second sacrificial layer on the second layer, the edges of the second layer and the edges of the second sacrificial layer are located outside the edges of the second pixel electrode and at least one portion of the first sacrificial layer is exposed. This is a method for manufacturing a display device, comprising: processing the second layer and the second sacrificial layer so that a portion is exposed, forming a first insulating film that covers at least the side surface of the first layer, the side surface of the second layer, the side surface and top surface of the first sacrificial layer, and the side surface and top surface of the second sacrificial layer; processing the first insulating film to form a first insulating layer such that, in cross-sectional view, one end is located on the first layer and the other end is located on the second layer; and processing the first sacrificial layer such that, in cross-sectional view, one end is aligned with or approximately aligned with the end of the first layer and the other end is located on the first layer, thereby forming a common electrode on the first layer and the second layer.

[0025] It is preferable to form a first insulating film using an inorganic material, then, after forming the first insulating film, to form a second insulating film on the first insulating film using an organic material, and then to process the second insulating film so that, in cross-sectional view, one end is located on the first layer and the other end is located on the second layer. It is preferable to use a photosensitive resin as the organic material.

[0026] Before forming the common electrode, it is preferable to form at least one of the following as a common layer on the first layer and the second layer: 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.

[0027] The first pixel electrode has a first conductive layer and a second conductive layer on the first conductive layer, and the second pixel electrode has a third conductive layer and a fourth conductive layer on the third conductive layer. Preferably, a first conductive film is formed, the first conductive layer and the third conductive layer are formed by processing the first conductive film, a second conductive film is formed covering the ends of the first conductive layer and the ends of the third conductive layer, and the second conductive film is processed to form a second conductive layer covering the ends of the first conductive layer and a fourth conductive layer covering the ends of the third conductive layer. [Effects of the Invention]

[0028] According to one aspect of the present invention, a high-definition display device can be provided. According to one aspect of the present invention, a high-resolution display device can be provided. According to one aspect of the present invention, a large-scale display device can be provided. According to one aspect of the present invention, a small-scale display device can be provided. According to one aspect of the present invention, a highly reliable display device can be provided.

[0029] According to one aspect of the present invention, a method for manufacturing a high-definition display device can be provided. According to one aspect of the present invention, a method for manufacturing a high-resolution display device can be provided. According to one aspect of the present invention, a method for manufacturing a large display device can be provided. According to one aspect of the present invention, a method for manufacturing a small display device can be provided. According to one aspect of the present invention, a method for manufacturing a highly reliable display device can be provided. According to one aspect of the present invention, a method for manufacturing a display device with a high yield can be provided.

[0030] Furthermore, the description of these effects does not preclude the existence of other effects. One aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description, drawings, and claims. [Brief explanation of the drawing]

[0031] Figure 1A is a top view showing an example of a display device. Figures 1B and 1C are cross-sectional views showing an example of a display device. Figures 2A to 2F are top views showing an example of a pixel. Figures 3A to 3F are top views showing an example of a pixel. Figures 4A to 4H are top views showing an example of a pixel. Figures 5A to 5D are top views showing an example of a pixel. Figures 6A to 6D are top views showing an example of a pixel. Figures 6E to 6G are cross-sectional views showing an example of a display device. Figures 7A to 7F are top views showing an example of a method for manufacturing a display device. Figures 8A to 8C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 9A to 9C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 10A to 10C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 11A to 11C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 12A to 12C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 13A to 13C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 14A to 14C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 15A to 15C are cross-sectional views showing an example of a method for manufacturing a display device. Figure 16 is a cross-sectional view showing an example of a method for manufacturing a display device. Figures 17A and 17B are cross-sectional views showing an example of a method for manufacturing a display device. Figures 18A to 18C are cross-sectional views showing an example of a display device. Figures 19A and 19B are cross-sectional views showing an example of a display device. Figures 20A and 20B are cross-sectional views showing an example of a display device. Figures 21A and 21B are cross-sectional views showing an example of a display device. Figures 22A and 22B are cross-sectional views showing an example of a display device. Figure 23 is a perspective view showing an example of a display device. Figure 24A is a cross-sectional view showing an example of a display device. Figures 24B and 24C are cross-sectional views showing an example of a transistor. Figures 25A to 25D are cross-sectional views showing an example of a display device. Figure 26 is a cross-sectional view showing an example of a display device. Figure 27 is a cross-sectional view showing an example of a display device. Figures 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. Figure 32 is a cross-sectional view showing an example of a display device. Figure 33 is a cross-sectional view showing an example of a display device. Figure 34A is a block diagram showing an example of a display device. Figures 34B to 34D show examples of pixel circuits. Figures 35A to 35D show examples of transistors. Figures 36A and 36B show examples of electronic devices. Figures 37A and 37B show examples of electronic devices. Figures 38A and 38B show examples of electronic devices. Figures 39A to 39D show examples of electronic devices. Figures 40A to 40G show examples of electronic devices. Figure 41A is a top view photograph of the display device of Example 1. Figure 41B is a cross-sectional view photograph of the display device of Example 1. Figures 42A to 42D are cross-sectional photographs of the display device of Example 1. Figure 43 is a photograph showing the display result of the display device of Example 2. Figures 44A and 44B show the measurement results of the emission spectrum of the display device of Example 2. Figures 45A to 45D are optical microscope images of the display device of Example 3. Figure 46 is a photograph showing the display result of the display device of Example 4. Figure 47 is a graph showing the leakage current measured for the display device in Example 4. Figure 48 is a graph showing the power consumption of the display device in Example 4. [Modes for carrying out the invention]

[0032] Embodiments will be described in detail with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be construed as being limited to the descriptions of the embodiments shown below.

[0033] In the invention described below, the same reference numerals are used in common across different drawings for identical parts or parts having similar functions, and repeated explanations are omitted. Furthermore, when referring to similar functions, the same hatching pattern may be used, and reference numerals may not be assigned.

[0034] Furthermore, the position, size, and scope of each component shown in the drawings may not represent the actual position, size, and scope for the sake of ease of understanding. Therefore, the disclosed invention is not necessarily limited to the position, size, and scope disclosed in the drawings.

[0035] It should be noted that the terms "film" and "layer" can be interchanged depending on the context or situation. For example, the term "conductive layer" can be changed to "conductive film." Or, for example, the term "insulating film" can be changed to "insulating layer."

[0036] (Embodiment 1) In this embodiment, a display device according to one aspect of the present invention and a method for manufacturing the same will be explained with reference to Figures 1 to 17.

[0037] In a method for manufacturing a display device according to one aspect of the present invention, a first layer (which can be described as an EL layer or a part of an EL layer) containing a light-emitting layer that emits light of a first color is formed on one surface, and then a first sacrificial layer is formed on the first layer. Then, a first resist mask is formed on the first sacrificial layer, and the first layer and the first sacrificial layer are processed using the first resist mask to form an island-shaped first layer. Subsequently, a second layer (which can be described as an EL layer or a part of an EL layer) containing a light-emitting layer that emits light of a second color is formed in an island shape using a second sacrificial layer and a second resist mask, similar to the first layer.

[0038] Thus, in the method for manufacturing a display device according to one aspect of the present invention, the island-shaped EL layer is not formed using a metal mask with a fine pattern, but rather formed by processing after the EL layer has been deposited on one surface. Therefore, it is possible to realize a high-definition display device or a display device with a high aperture ratio, which has been difficult to achieve until now. Furthermore, since the EL layer can be manufactured separately for each color, it is possible to realize a display device that is extremely vivid, has high contrast, and has high display quality. In addition, by providing a sacrificial layer (which may also be called a mask layer) on the EL layer, the damage that the EL layer receives during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0039] While it is difficult to reduce the spacing between adjacent light-emitting devices to less than 10 μm using, for example, a metal mask formation method, the above method allows for narrowing the spacing to less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, or even 1 μm or less. Furthermore, by using, for example, an exposure apparatus for LSIs, the spacing can be narrowed to less than 500 nm, less than 200 nm, less than 100 nm, and even less than 50 nm. This significantly reduces the area of ​​the non-emitting region that may exist between two light-emitting devices, making it possible to approach an aperture ratio of 100%. For example, an aperture ratio of 50% or more, 60% or more, 70% or more, 80% or more, and even 90% or more, can be achieved, and even less than 100%.

[0040] Furthermore, the pattern of the EL layer itself (which can also be called the processing size) can be made significantly smaller compared to when a metal mask is used. Also, for example, when a metal mask is used to create different EL layers, variations in thickness occur between the center and edges of the EL layer, resulting in a smaller effective area that can be used as an emitting region relative to the area of ​​the EL layer. On the other hand, with the above manufacturing method, a film deposited to a uniform thickness is processed, so island-shaped EL layers can be formed with a uniform thickness. Therefore, even with a fine pattern, almost the entire area can be used as an emitting region. As a result, a display device that combines high resolution and a high aperture ratio can be manufactured.

[0041] In one embodiment of the present invention, the display device is configured such that the light-emitting layer covers the upper and side surfaces of the pixel electrodes. In other words, the edges of the light-emitting layer are located outside the edges of the pixel electrodes. This configuration allows for a higher aperture ratio compared to a configuration in which the edges of the light-emitting layer are located inside the edges of the pixel electrodes.

[0042] Furthermore, by covering the sides of the pixel electrodes with a light-emitting layer, contact between the pixel electrodes and the common electrodes can be suppressed, thereby preventing short circuits in the light-emitting device.

[0043] Here, the first layer and the second layer each include at least an emissive layer and preferably consist of multiple layers. Specifically, it is preferable to have one or more layers on the emissive layer. By having other layers between the emissive layer and the sacrificial layer, it is possible to suppress the exposure of the emissive layer to the outermost surface during the manufacturing process of the display device and reduce the damage the emissive layer receives. This can improve the reliability of the light-emitting device. Therefore, it is preferable that the first layer and the second layer each include an emissive layer and a carrier transport layer (electron transport layer or hole transport layer) on the emissive layer.

[0044] Furthermore, in light-emitting devices that emit light of different colors, it is not necessary to fabricate all the layers constituting the EL layer separately; some layers can be formed in the same process. Examples of layers 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 aspect of the present invention, some of the layers constituting the EL layer are formed in island-like structures for each color, then at least a portion of the sacrificial layer is removed, and the remaining layers constituting the EL layer and a common electrode (also called an upper electrode) are formed in common (as a single film) for each color of light-emitting device. For example, the carrier injection layer and the common electrode can be formed in common for each color of light-emitting device. On the other hand, the carrier injection layer is often a relatively conductive layer within the EL layer. Therefore, there is a risk of the light-emitting device short-circuiting if the carrier injection layer comes into contact with the side surface of some of the island-like layers of the EL layer, or with the side surface of the pixel electrode. Furthermore, even when the carrier injection layer is arranged in an island-like configuration and a common electrode is formed in common for each color light-emitting device, 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.

[0045] Therefore, a display device according to one aspect of the present invention has an insulating layer that covers at least the side surface of an island-shaped light-emitting layer.

[0046] This prevents at least a portion of the island-shaped EL layer and the pixel electrodes from coming into contact with the carrier injection layer or common electrode. Therefore, it is possible to suppress short circuits in the light-emitting device and improve the reliability of the light-emitting device.

[0047] Furthermore, by providing this insulating layer, the gaps between adjacent island-shaped EL layers can be filled, thereby reducing the unevenness of the surface on which layers (carrier injection layers, common electrodes, etc.) are formed on the island-shaped EL layers, making them flatter. Consequently, the coverage of the carrier injection layer or common electrode can be improved. This prevents the common electrode from breaking into steps.

[0048] In this specification, "step breakage" refers to the phenomenon in which a layer, film, or electrode is divided due to the shape of the surface on which it is formed (e.g., a step).

[0049] Furthermore, the insulating layer can be provided in contact with the island-shaped EL layer. This prevents the EL layer from peeling off. The close contact between the insulating layer and the island-shaped EL layer provides the effect of fixing or bonding adjacent island-shaped EL layers together.

[0050] Furthermore, when providing the insulating layer, the opening of the cathode contact portion (connection portion 140, described later) can be made at the same time. In other words, the insulating layer can be formed without increasing the manufacturing process required to provide the opening. For example, when the insulating layer is formed from a photosensitive resin, the formation of the insulating layer and the exposure of the conductive layer at the cathode contact portion can be performed in a single exposure.

[0051] A display device according to one aspect of the present invention includes a pixel electrode that functions as an anode, and island-shaped layers arranged on the pixel electrode in the following order: a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer, an insulating layer provided to cover the sides of each of the hole injection layer, hole transport layer, light-emitting layer, and electron transport layer, an electron injection layer provided on the electron transport layer, and a common electrode provided on the electron injection layer that functions as a cathode.

[0052] Alternatively, a display device according to one aspect of the present invention includes a pixel electrode that functions as a cathode, an island-shaped electron injection layer, an electron transport layer, an emissive layer, and a hole transport layer provided in this order on the pixel electrode, an insulating layer provided to cover the respective sides of the electron injection layer, electron transport layer, emissive layer, and hole transport layer, a hole injection layer provided on the hole transport layer, and a common electrode provided on the hole injection layer that functions as an anode.

[0053] Alternatively, a display device according to one aspect of the present invention includes a pixel electrode, a first light-emitting unit on the pixel electrode, a charge generation layer (also called an intermediate layer) on the first light-emitting unit, a second light-emitting unit on the charge generation layer, an insulating layer provided to cover the sides of the first light-emitting unit, the charge generation layer, and the second light-emitting unit, and a common electrode provided on the second light-emitting unit. A common layer may be provided between the second light-emitting unit and the common electrode for each color of light-emitting device.

[0054] Hole injection layers, electron injection layers, or charge generation layers are often relatively conductive layers within the EL layer. In a display device according to one aspect of the present invention, the sides of these layers are covered with an insulating layer, thereby suppressing contact with common electrodes and the like. Therefore, short circuits in the light-emitting device can be suppressed, and the reliability of the light-emitting device can be improved.

[0055] This configuration makes it possible to manufacture highly detailed, high-resolution, and reliable display devices. For example, it is not necessary to apply special pixel arrangement methods such as the PenTile method to artificially increase detail; even with an arrangement method that uses three or more subpixels per pixel, an extremely high-resolution display device can be realized. For example, with a so-called stripe arrangement in which R, G, and B are each arranged in one direction, a display device with a detail of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, even 3000 ppi or more, and even 5000 ppi or more can be realized.

[0056] The insulating layer may be a single-layer structure or a multi-layer structure. In particular, it is preferable to apply a two-layer insulating layer. For example, since the first layer of the insulating layer is formed in contact with the EL layer, it is preferable to form it using an inorganic insulating material. In particular, it is preferable to form it using the atomic layer deposition (ALD) method, which causes less film deposition damage. In addition, it is preferable to form the inorganic insulating layer using the sputtering method, chemical vapor deposition (CVD) method, or plasma chemical vapor deposition (PECVD) method, which have a faster film deposition rate than the ALD method. This makes it possible to manufacture highly reliable display devices with high productivity. Furthermore, it is preferable to form the second layer of the insulating layer using an organic material so as to flatten the recesses formed in the first insulating layer.

[0057] For example, an aluminum oxide film formed by the ALD method can be used as the first layer of the insulating layer, and a photosensitive organic resin film can be used as the second layer of the insulating layer.

[0058] When 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 create a configuration in which the photosensitive organic resin film and the side surface of the EL layer do not come into direct contact. This makes it possible to suppress the dissolution of the EL layer by organic solvents.

[0059] Furthermore, a single-layer insulating layer may be formed. For example, by forming a single-layer insulating layer 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. Alternatively, by forming a single-layer insulating layer using an organic material, for example, the space between adjacent EL layers can be filled with the insulating layer and flattened. This can improve the coverage of the common electrode (upper electrode) formed on the EL layer and the insulating layer. In particular, it is preferable to use an organic material that causes less damage to the EL layer.

[0060] Furthermore, in the display device of this embodiment, since there is no need to provide an insulating layer covering the edges of the pixel electrodes between the pixel electrodes and the EL layer, the spacing between adjacent light-emitting devices can be made extremely narrow. Therefore, the display device can be made higher resolution or more detailed. In addition, a mask for forming the insulating layer is not required, which can reduce the manufacturing cost of the display device.

[0061] [Example of display device configuration 1] Figures 1A to 1C show a display device according to one embodiment of the present invention.

[0062] Figure 1A shows a top view of the display device 100. The display device 100 has a display unit in which a plurality of pixels 110 are arranged in a matrix, and a connection unit 140 outside the display unit. The connection unit 140 can also be called a cathode contact unit.

[0063] A stripe array is applied to pixel 110 shown in Figure 1A. Pixel 110 shown in Figure 1A is composed of three subpixels: subpixels 110a, 110b, and 110c. Each subpixel 110a, 110b, and 110c has a light-emitting device that emits light of a different color. Examples of subpixels 110a, 110b, and 110c include subpixels of three colors: red (R), green (G), and blue (B); and subpixels of three colors: yellow (Y), cyan (C), and magenta (M).

[0064] The top surface shape of the subpixel shown in Figure 1A corresponds to the top surface shape of the light-emitting region.

[0065] Furthermore, the circuit layout constituting the subpixel is not limited to the subpixel range shown in Figure 1A, but may be located outside of it. For example, some or all of the transistors in subpixel 110a may be located outside the range of subpixel 110a shown in Figure 1A. For example, the transistors in subpixel 110a may have a portion located within the range of subpixel 110b, or a portion located within the range of subpixel 110c.

[0066] In Figure 1A, the aperture ratios (size, also known as the size of the light-emitting area) of the sub-pixels 110a, 110b, and 110c are shown to be equal or approximately equal, but one aspect of the present invention is not limited thereto. The aperture ratios of the sub-pixels 110a, 110b, and 110c can be determined as appropriate. The aperture ratios of the sub-pixels 110a, 110b, and 110c may be different, or two or more aperture ratios may be equal or approximately equal.

[0067] Figure 1A shows an example where subpixels of different colors are arranged in the X direction, and subpixels of the same color are arranged in the Y direction. Alternatively, subpixels of different colors may be arranged in the Y direction, and subpixels of the same color may be arranged in the X direction.

[0068] Figure 1A shows an example where the connection portion 140 is located below the display portion in a top view, but it is not particularly limited. The connection portion 140 only needs to be provided at least one location on the top, right, left, or bottom of the display portion in a top view, and may be provided so as to surround all four sides of the display portion. Also, the connection portion 140 may be singular or multiple.

[0069] Figure 1B shows a cross-sectional view between the dashed lines X1 and X2 in Figure 1A, and Figure 1C shows a cross-sectional view between the dashed lines Y1 and Y2 in Figure 1A.

[0070] As shown in Figure 1B, the display device 100 has light-emitting devices 130a, 130b, and 130c arranged on a layer 101 containing transistors, and a protective layer 131 is provided to cover these light-emitting devices. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. In addition, an insulating layer 125 and an insulating layer 127 on the insulating layer 125 are provided in the region between adjacent light-emitting devices.

[0071] A display device according to one aspect of the present invention may be a top-emission type that emits light in the direction opposite to the substrate on which the light-emitting device is formed, a bottom-emission type that emits light toward the substrate on which the light-emitting device is formed, or a dual-emission type that emits light on both sides.

[0072] The layer 101 containing transistors can be, for example, a laminated structure in which multiple transistors are provided on a substrate and an insulating layer is provided to cover these transistors. The layer 101 containing transistors may have recesses between adjacent light-emitting devices. For example, recesses may be provided in the insulating layer located on the outermost surface of the layer 101 containing transistors. Examples of the configuration of the layer 101 containing transistors will be described later in Embodiments 3 and 4.

[0073] The conductive layers 111a, 111b, and 111c are each electrically connected to the transistors provided on layer 101, which contains the transistors. The conductive layers 111a, 111b, and 111c can be described as layers that electrically connect the light-emitting device and the transistors. Alternatively, the conductive layers 111a, 111b, and 111c can be described as parts of the pixel electrodes of the light-emitting device.

[0074] It is preferable that layer 128 is embedded in the recesses of conductive layers 111a, 111b, and 111c. Furthermore, it is preferable to form conductive layer 112a on conductive layers 111a and 128, conductive layer 112b on conductive layers 111b and 128, and conductive layer 112c on conductive layers 111c and 128. The conductive layers 112a, 112b, and 112c function as pixel electrodes of a light-emitting device.

[0075] Layer 128 has the function of flattening the recesses of the conductive layers 111a, 111b, and 111c. By providing layer 128, the unevenness of the surface on which the EL layer is formed can be reduced, and the coverage can be improved. Furthermore, by providing conductive layers 112a, 112b, and 112c that are electrically connected to conductive layers 111a, 111b, and 111c on the conductive layers 111a, 111b, and 111c and on layer 128, the regions that overlap with the recesses of conductive layers 111a, 111b, and 111c can also be used as light-emitting regions. This makes it possible to increase the aperture ratio of the pixels.

[0076] Layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used for layer 128 as appropriate. In particular, it is preferable that layer 128 be formed using an insulating material.

[0077] As layer 128, an insulating layer having an organic material can be suitably used. For example, acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be used as layer 128. Alternatively, a photosensitive resin can be used as layer 128. The photosensitive resin can be a positive-type material or a negative-type material.

[0078] The conductive layer 112a is provided on the conductive layer 111a and on 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. Preferably, 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.

[0079] Similarly, the conductive layer 112b is provided on the conductive layer 111b and on 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. Preferably, 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.

[0080] The conductive layer 112c is provided on the conductive layer 111c and on 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. Preferably, 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.

[0081] Each of the light-emitting devices 130a, 130b, and 130c emits light of a different color. Preferably, the light-emitting devices 130a, 130b, and 130c are a combination that emits, for example, red (R), green (G), and blue (B) light.

[0082] As the light-emitting devices 130a, 130b, and 130c, it is preferable to use, for example, OLED (Organic Light Emitting Diode) or QLED (Quantum-dot Light Emitting Diode). Examples of light-emitting materials (also called luminescent materials) for the light-emitting devices include fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF) materials. As the TADF material, a material in thermal equilibrium between the singlet excited state and the triplet excited state may be used. Since such TADF materials have a shorter emission lifetime (excitation lifetime), it is possible to suppress the decrease in efficiency in the high-brightness region of the light-emitting device. In addition, inorganic compounds (such as quantum dot materials) may be used as the light-emitting material for the light-emitting device.

[0083] The light-emitting device has an EL layer between a pair of electrodes. In this specification, one of the pair of electrodes may be referred to as the pixel electrode and the other as the common electrode.

[0084] In a light-emitting device, one electrode functions as the anode and the other as the cathode. The following explanation uses the example where the pixel electrode functions as the anode and the common electrode functions as the cathode.

[0085] The light-emitting device 130a includes a conductive layer 112a on a layer 101 containing 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 layers 111a, 112a, 126a, and 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 has the function of a pixel electrode for the light-emitting device 130a; other conductive layers do not need to be provided. In addition, in the light-emitting device 130a, the first layer 113a and the fourth layer 114 can be collectively called the EL layer.

[0086] The configuration of the light-emitting device in this embodiment is not particularly limited and may be a single structure or a tandem structure. An example of the configuration of the light-emitting device will be described later in Embodiment 2.

[0087] The light-emitting device 130b includes a conductive layer 112b on layer 101 containing a transistor, a conductive layer 126b on conductive layer 112b, a conductive layer 129b on conductive layer 126b, an island-shaped second layer 113b on 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 conductive layer 111b may also be considered a component of the light-emitting device 130b. Conductive layer 112b can function as a pixel electrode of the light-emitting device 130b. Note that at least one of conductive layers 111b, 112b, 126b, and 129b functions as a pixel electrode of the light-emitting device 130b. Of the conductive layers 111b, 112b, 126b, and 129b, at least one layer has the function of a pixel electrode for the light-emitting device 130b; other conductive layers do not need to be provided. In addition, in the light-emitting device 130b, the second layer 113b and the fourth layer 114 can be collectively called the EL layer.

[0088] The light-emitting device 130c includes a conductive layer 112c on a layer 101 containing 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. Note that 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. Note that at least one of the conductive layers 111c, 112c, 126c, and 129c functions as a pixel electrode of the light-emitting device 130c. Of the conductive layers 111c, 112c, 126c, and 129c, at least one layer has the function of a pixel electrode for the light-emitting device 130c; other conductive layers do not need to be provided. In addition, in the light-emitting device 130c, the third layer 113c and the fourth layer 114 can be collectively called the EL layer.

[0089] Each color of light-emitting device shares the same film as a common electrode. The common electrode 115, which is common to all colored light-emitting devices, is electrically connected to a conductive layer 123 provided at the connection part 140 (see Figure 1C). As a result, the same potential is supplied to the common electrode 115 of each colored light-emitting device. The conductive layer 123 can have conductive layers formed from the same material and using the same process as at least one of the conductive layers 111a, 112a, 126a, and 129a. Figure 1C shows an example in which the conductive layer 123 has three conductive layers formed from the same material and using the same process as conductive layers 111a, 112a, and 129a.

[0090] In Figure 1B, the conductive layers 111a, 112a, 126a, and 129a each have different end positions. Specifically, the end of conductive layer 112a is located outside the end of conductive layer 111a, the end of conductive layer 126a is located outside the end of conductive layer 112a, and the end of conductive layer 129a is located outside the end of conductive layer 126a. The shapes of the conductive layers 111a, 112a, 126a, and 129a are not limited to the configuration shown in Figure 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 identical or approximately identical.

[0091] Furthermore, if the edges are aligned or roughly aligned, and the top surface shapes match or roughly match, then in a top view, at least a portion of the contours overlaps between the stacked layers. This includes, for example, cases where the upper and lower layers are processed with the same mask pattern, or partially with the same mask pattern. However, strictly speaking, the contours may not overlap, and the upper layer may be located inside the lower layer, or the upper layer may be located outside the lower layer; in this case as well, the edges are said to be roughly aligned, or the top surface shapes roughly match.

[0092] In the light-emitting device 130a, the first layer 113a covers the sides of the conductive layers 111a, 112a, 126a, and 129a. Furthermore, the edges of the first layer 113a are located outside the edges of the conductive layers 111a, 112a, 126a, and 129a. This configuration allows for an increase in the aperture ratio of the pixels. In addition, contact between the conductive layers 111a, 112a, 126a, and 129a and the common electrode 115 is suppressed, thereby preventing short circuits in the light-emitting device. The same applies to light-emitting devices 130b and 130c.

[0093] The sides of the first layer 113a, the second layer 113b, and the third layer 113c are covered by insulating layers 125 and 127. This prevents the fourth layer 114 (or common electrode 115) from coming into contact with any of the sides of the first layer 113a, the second layer 113b, and the third layer 113c, thereby preventing a short circuit in the light-emitting device.

[0094] The insulating layer 125 can be configured to be in contact with the respective sides of the first layer 113a, the second layer 113b, and the third layer 113c.

[0095] The insulating layer 127 is provided on the insulating layer 125 so as to fill the recesses formed in the insulating layer 125. The insulating layer 127 can be configured to overlap (or cover) the sides of the first layer 113a, the second layer 113b, and the third layer 113c via the insulating layer 125.

[0096] Note that it is not necessary to provide either the insulating layer 125 or the insulating layer 127. For example, if the insulating layer 125 is not provided, the insulating layer 127 can be configured to be in contact with the respective sides of the first layer 113a, the second layer 113b, and the third layer 113c. The insulating layer 127 can be provided to fill the spaces between the EL layers of each light-emitting device.

[0097] By having one or both of the insulating layer 125 and insulating layer 127 fill the gaps between the EL layers of each light-emitting device, delamination of the EL layers can be prevented, thereby improving the reliability of the light-emitting devices. Furthermore, the manufacturing yield of the light-emitting devices can be increased.

[0098] One or both of the insulating layer 125 and insulating layer 127 may cover a portion of the upper surface of the first layer 113a, the second layer 113b, and the third layer 113c, respectively. By having one or both of the insulating layer 125 and insulating layer 127 cover not only the sides but also the top surface of the EL layer, delamination of the EL layer can be further prevented, thereby improving the reliability of the light-emitting device. Furthermore, the manufacturing yield of the light-emitting device can be further improved.

[0099] Furthermore, a sacrificial layer 118a is located on the first layer 113a. In Figure 1B, one end of the sacrificial layer 118a is aligned with or approximately aligned with the end of the first layer 113a, and the other end of the sacrificial layer 118a is located on the first layer 113a. Thus, in one embodiment of the present invention, the sacrificial layer used during manufacturing may remain. The same applies to the sacrificial layer 118b on the second layer 113b and the sacrificial layer 118c on the third layer 113c. Specifically, one end of the sacrificial layer 118b is aligned with or approximately aligned with the 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 is aligned with or approximately aligned with the end of the third layer 113c. The other end of the sacrificial layer 118c is located on the third layer 113c.

[0100] Furthermore, a display device according to one aspect of the present invention may have a configuration that includes one or more of the sacrificial layers 118a, 118b, and 118c, or it may have a configuration that does not include any of the three.

[0101] One or both of the insulating layer 125 and insulating layer 127 may be provided on the sacrificial layer 118a. Similarly, one or both of the insulating layer 125 and insulating layer 127 may be provided on the sacrificial layer 118b and the sacrificial layer 118c.

[0102] The fourth layer 114 and the common electrode 115 are provided on 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 difference exists due to the region where the pixel electrode and EL layer are provided and the region where the pixel electrode and EL layer are not provided (the region between the light-emitting devices). In one embodiment of the present invention, the presence of the insulating layer 125 and the insulating layer 127 can flatten this step difference and improve the coverage of the fourth layer 114 and the common electrode 115. Therefore, connection failures due to step breaks in the common electrode 115 can be suppressed. Alternatively, the increase in electrical resistance due to local thinning of the common electrode 115 caused by the step difference can be suppressed.

[0103] To improve the flatness of the formation surfaces of the fourth layer 114 and the common electrode 115, it is preferable that the heights of the upper surfaces of the insulating layer 125 and the insulating layer 127 match or approximately match the height of at least one of the upper surfaces of the first layer 113a, the second layer 113b, and the third layer 113c, respectively. Furthermore, it is preferable that the upper surface of the insulating layer 127 has a flat shape, and may have convex portions, convex curved surfaces, concave curved surfaces, or recesses.

[0104] The insulating layer 125 has regions that are in contact with the sides 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, it is possible to suppress the intrusion of impurities (oxygen, moisture, etc.) into the interior from the sides of the first layer 113a, the second layer 113b, and the third layer 113c, thereby enabling a highly reliable display device.

[0105] In a cross-sectional view, if the width (thickness) of the insulating layer 125 in the region in contact with the sides of the first layer 113a, the second layer 113b, and the third layer 113c is large, the spacing between the first layer 113a, the second layer 113b, and the third layer 113c may increase, resulting in a lower aperture ratio. Conversely, if the width (thickness) of the insulating layer 125 is small, the effect of suppressing the intrusion of impurities into the interior from the sides of the first layer 113a, the second layer 113b, and the third layer 113c may be reduced. The width (thickness) of the insulating layer 125 in the region in contact with the sides 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, more preferably 5 nm to 150 nm, more preferably 5 nm to 100 nm, more preferably 10 nm to 100 nm, and more preferably 10 nm to 50 nm. By setting the width (thickness) of the insulating layer 125 within the above range, a display device with a high aperture ratio and high reliability can be made.

[0106] The insulating layer 125 can be an insulating layer having an inorganic material. For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used for the insulating layer 125. The insulating layer 125 may be a single layer or a laminated structure. Examples of oxide insulating films include silicon oxide film, aluminum oxide film, magnesium oxide film, indium gallium zinc oxide film, gallium oxide film, germanium oxide film, yttrium oxide film, zirconium oxide film, lanthanum oxide film, neodymium oxide film, hafnium oxide film, and tantalum oxide film. Examples of nitride insulating films include silicon nitride film and aluminum nitride film. Examples of oxidative nitride insulating films include silicon oxidative nitride film and aluminum oxidative nitride film. Examples of nitride oxide insulating films include silicon nitride oxide film and aluminum nitride oxide film. In particular, aluminum oxide is preferred because it has a high selectivity ratio with the EL layer during etching and has the function of protecting the EL layer during the formation of the insulating layer 127, which will be described later. In particular, by applying inorganic insulating films such as aluminum oxide films, hafnium oxide films, and silicon oxide films formed by the ALD method to the insulating layer 125, it is possible to form an insulating layer 125 with fewer pinholes and excellent function in protecting the EL layer.

[0107] In this specification, the term "oxide-nitride" refers to a material in which the oxygen content is greater than the nitrogen content, and the term "nitride oxide" refers to a material in which the nitrogen content is greater than the oxygen content. For example, when "silicon oxynitride" is written, it refers to a material in which the oxygen content is greater than the nitrogen content, and when "silicon nitride oxide" is written, it refers to a material in which the nitrogen content is greater than the oxygen content.

[0108] The insulating layer 125 can be formed using sputtering, CVD, PLD, ALD, or other methods. It is preferable to form the insulating layer 125 using the ALD method, which provides good coverage.

[0109] The insulating layer 127 provided on the insulating layer 125 has the function of flattening the recess in the insulating layer 125 formed between adjacent light-emitting devices. In other words, the presence of the insulating layer 127 improves the flatness of the surface on which the common electrode 115 is formed. Suitable insulating layers 127 include those made of organic materials. For example, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol 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 may be used as the insulating layer 127. Furthermore, a photosensitive resin can be used as the insulating layer 127. A photoresist may be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0110] The difference between the height of the upper surface of the insulating layer 127 and the height of the upper surface of any of the first layer 113a, the second layer 113b, and the third layer 113c is preferably 0.5 times or less the thickness of the insulating layer 127, and more preferably 0.3 times or less. Alternatively, the insulating layer 127 may be provided such that the upper surface of any of the first layer 113a, the second layer 113b, and the third layer 113c is higher than the upper surface of the insulating layer 127. Alternatively, the insulating layer 127 may be provided such that the upper surface of the insulating layer 127 is higher than the upper surface of the light-emitting layer of the first layer 113a, the second layer 113b, or the third layer 113c.

[0111] Of the pixel electrodes and common electrodes, the electrode that extracts light should preferably use a conductive film that transmits visible light. Furthermore, it is preferable to use a conductive film that reflects visible light on the electrode that does not extract light.

[0112] As materials for forming the pair of electrodes (pixel electrode and common electrode) of a light-emitting device, metals, alloys, electrically conductive compounds, and mixtures thereof can be used as appropriate. Specifically, examples include indium tin oxide (In-Sn oxide, also called ITO), In-Si-Sn oxide (also called ITSO), indium zinc oxide (In-Zn oxide), In-W-Zn oxide, aluminum-containing alloys such as aluminum, nickel, and lanthanum alloys (Al-Ni-La), and silver-containing alloys such as silver-magnesium alloys and silver-palladium-copper alloys (Ag-Pd-Cu, also written as APC). In addition, metals such as aluminum (Al), magnesium (Mg), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys containing these in appropriate combinations can also be used. Furthermore, elements belonging to Group 1 or Group 2 of the periodic table not exemplified above (e.g., lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these in appropriate combinations, graphene, and the like can also be used.

[0113] It is preferable that the light-emitting device has a microcavity structure. Therefore, it is preferable that one of the pair of electrodes in the light-emitting device has an electrode that is transparent to and reflective to visible light (a semi-transmissive / semi-reflective electrode), and the other has an electrode that is reflective to visible light (a reflective electrode). By having a microcavity structure in the light-emitting device, the light emitted from the light-emitting layer can be resonated between the two electrodes, thereby strengthening the light emitted from the light-emitting device.

[0114] Furthermore, semi-transmissive / semi-reflective electrodes can have a laminated structure consisting of a reflective electrode and an electrode that transmits visible light (also called a transparent electrode).

[0115] The light transmittance of the transparent electrode shall be 40% or more. For example, it is preferable to use an electrode in the light-emitting device that has a transmittance of 40% or more for visible light (light with a wavelength of 400 nm or more and less than 750 nm). The visible light reflectance of the semi-transparent / semi-reflective electrode shall be 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes shall be 1 × 10⁻⁶ -2 A value of Ωcm or less is preferable.

[0116] For example, conductive layers that function as reflective electrodes may be used for conductive layers 111a and 112a, and conductive layers that function as transparent electrodes may be used for conductive layers 126a and 129a.

[0117] The first layer 113a, the second layer 113b, and the third layer 113c are each provided in an island-like manner. The first layer 113a, the second layer 113b, and the third layer 113c each have an emissive layer. Preferably, the first layer 113a, the second layer 113b, and the third layer 113c each have an emissive layer that emits light of a different color.

[0118] The luminescent layer is a layer containing a luminescent material. The luminescent layer may contain one or more types of luminescent materials. Suitable luminescent materials include those exhibiting colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red. Furthermore, materials emitting near-infrared light may also be used as luminescent materials.

[0119] Examples of luminescent materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0120] 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.

[0121] Examples of phosphorescent materials include organometallic complexes (especially iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton; organometallic complexes (especially iridium complexes) using phenylpyridine derivatives having electron-withdrawing groups as ligands; platinum complexes; and rare earth metal complexes.

[0122] The light-emitting layer may contain one or more types of organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). One or more of these organic compounds may be hole-transporting materials and / or electron-transporting materials. Alternatively, one or more of these organic compounds may be bipolar materials or TADF materials.

[0123] The light-emitting layer preferably comprises, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that readily forms an excitation complex. This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excitation complex to the light-emitting substance (phosphorescent material). By selecting a combination that forms an excitation complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the light-emitting substance, energy transfer becomes smoother, and light emission can be obtained efficiently. This configuration simultaneously achieves high efficiency, low-voltage operation, and a long lifespan for the light-emitting device.

[0124] The first layer 113a, the second layer 113b, and the third layer 113c may further include layers other than the light-emitting layer that contain a material with high hole injection properties, a material with high hole transport properties (also referred to as a hole-transporting material), a hole-blocking material, a material with high electron transport properties (also referred to as an electron-transporting material), a material with high electron injection properties, an electron-blocking material, or a bipolar material (a material with high electron transport and hole transport properties, also referred to as a bipolar material).

[0125] For example, the first layer 113a, the second layer 113b, and the third layer 113c may each have one or more of the following: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0126] Among the EL layers, one or more of the following layers can be applied to be commonly formed in each color light-emitting device: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer. For example, a carrier injection layer (hole injection layer or electron injection layer) may be formed as the fourth layer 114. Furthermore, all layers of the EL layer may be manufactured separately for each color. In other words, the EL layer does not necessarily have to have layers commonly formed in each color light-emitting device.

[0127] Preferably, the first layer 113a, the second layer 113b, and the third layer 113c each have an emissive layer and a carrier transport layer on the emissive layer. This suppresses exposure of the emissive layer to the outermost surface during the manufacturing process of the display device 100, thereby reducing damage to the emissive layer. This improves the reliability of the light-emitting device.

[0128] The hole injection layer is a layer that injects holes from the anode into the hole transport layer, and is a layer containing a material with high hole injection capabilities. Examples of materials with high hole injection capabilities include aromatic amine compounds and composite materials containing hole transport materials and acceptor materials (electron-accepting materials).

[0129] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light-emitting layer. The hole transport layer is a layer containing a hole-transporting material. The hole-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having a hole mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher hole transport capabilities than electron transport. Preferred hole transport materials include π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, furan derivatives, etc.) and aromatic amines (compounds having an aromatic amine skeleton), which are materials with high hole transport capabilities.

[0130] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light-emitting layer. The electron transport layer is a layer containing an electron-transporting material. The electron-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having an electron mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes. Examples of electron-transporting materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds, which are all highly electron-transporting materials.

[0131] The electron injection layer is a layer that injects electrons from the cathode into the electron transport layer, and is a layer containing a material with high electron-injection properties. Alkali metals, alkaline earth metals, or compounds thereof can be used as materials with high electron-injection properties. Composite materials containing both electron-transporting materials and donor materials (electron-donating materials) can also be used as materials with high electron-injection properties.

[0132] Examples of electron injection layers include lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), and calcium fluoride (CaF). x (where X is any number), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatrium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatrium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatrium (abbreviation: LiPPP), lithium oxide (LiO x Alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. Furthermore, the electron injection layer may be a multilayer structure of two or more layers. For example, this multilayer structure may consist of lithium fluoride as the first layer and ytterbium as the second layer.

[0133] Alternatively, an electron-transporting material may be used as the electron injection layer. For example, a compound having a lone pair of electrons and an electron-deficient heteroaromatic ring can be used as the electron-transporting material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), or a triazine ring can be used.

[0134] Furthermore, it is preferable that the lowest unoccupied molecular orbital (LUMO) of an organic compound containing a lone pair of electrons is between -3.6 eV and -2.3 eV. In addition, the highest occupied molecular orbital (HOMO) level and LUMO level of an organic compound can generally be estimated by methods such as cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy.

[0135] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz) can be used in organic compounds containing lone pairs of electrons. NBPhen has a higher glass transition temperature (Tg) and superior heat resistance compared to BPhen.

[0136] Furthermore, when fabricating a tandem light-emitting device, a charge generation layer (also called an intermediate layer) is provided between the two light-emitting units. The charge generation 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 the pair of electrodes.

[0137] The charge generation layer has at least a charge generation region. The charge generation region preferably includes an acceptor material, and preferably includes, for example, a hole transport material and an acceptor material applicable to the hole injection layer described above.

[0138] Furthermore, the charge generation layer preferably includes a layer containing a material with high electron injection properties. This layer can also be called an electron injection buffer layer. The electron injection buffer layer is preferably provided between the charge generation region and the electron transport layer. By providing an electron injection buffer layer, the injection barrier between the charge generation region and the electron transport layer can be relaxed, allowing electrons generated in the charge generation region to be easily injected into the electron transport layer.

[0139] The electron injection buffer layer preferably contains an alkali metal or an alkaline earth metal, and can, for example, a compound of an alkali metal or an alkaline earth metal. Specifically, the electron injection buffer layer preferably has an inorganic compound containing an alkali metal and oxygen, or an inorganic compound containing an alkaline earth metal and oxygen, and more preferably has an inorganic compound containing lithium and oxygen (such as lithium oxide (Li2O)). In addition, any other material applicable to the electron injection layer can be suitably used for the electron injection buffer layer.

[0140] The charge generation layer preferably has a layer containing a material with high electron transport properties. This layer can also be called an electron relay layer. The electron relay layer is preferably provided between the charge generation region and the electron injection buffer layer. If the charge generation layer does not have an electron injection buffer layer, the electron relay layer is preferably provided between the charge generation region and the electron transport layer. The electron relay layer has the function of preventing interaction between the charge generation region and the electron injection buffer layer (or electron transport layer) and smoothly transferring electrons.

[0141] As the electron relay layer, it is preferable to use a phthalocyanine-based material such as copper(II) phthalocyanine (abbreviated as CuPc), or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0142] Furthermore, the charge generation region, electron injection buffer layer, and electron relay layer described above may not be clearly distinguishable depending on their cross-sectional shape or characteristics.

[0143] The charge generation layer may have a donor material instead of an acceptor material. For example, the charge generation layer may have a layer containing an electron transport material and a donor material, which is applicable to the electron injection layer described above.

[0144] When stacking light-emitting units, the rise in driving voltage can be suppressed by providing a charge generation layer between the two light-emitting units.

[0145] The light-emitting device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-emitting device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0146] It is preferable to have a protective layer 131 on the light-emitting devices 130a, 130b, and 130c. Providing the protective layer 131 can improve the reliability of the light-emitting devices. The protective layer 131 may be a single layer or a laminated structure of two or more layers.

[0147] The protective layer 131 can be at least one of an insulating film, a semiconductor film, and a conductive film.

[0148] The presence of an inorganic film in the protective layer 131 prevents oxidation of the common electrode 115 and suppresses the intrusion of impurities (such as moisture and oxygen) into the light-emitting devices 130a, 130b, and 130c, thereby suppressing degradation of the light-emitting devices and improving the reliability of the display device.

[0149] For the protective layer 131, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxidative nitride insulating films include silicon oxide nitride films and aluminum oxide nitride films. Examples of nitride oxide insulating films include silicon oxide nitride films and aluminum oxide nitride films.

[0150] The protective layer 131 preferably has a nitride insulating film or a nitride oxide insulating film, and more preferably has a nitride insulating film.

[0151] Furthermore, the protective layer 131 may also be an inorganic film containing ITO, In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or indium gallium zinc oxide (also known as In-Ga-Zn oxide or IGZO). The inorganic film is preferably highly resistive, and more specifically, it is preferably more resistive than the common electrode 115. The inorganic film may further contain nitrogen.

[0152] When the light emitted from a light-emitting device is extracted via a protective layer 131, it is preferable that the protective layer 131 has high transmittance to visible light. For example, ITO, IGZO, and aluminum oxide are preferred because they are inorganic materials with high transmittance to visible light.

[0153] As the protective layer 131, for example, a laminated structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a laminated structure of an aluminum oxide film and an IGZO film on the aluminum oxide film can be used. By using such a laminated structure, it is possible to suppress the penetration of impurities (water, oxygen, etc.) into the EL layer.

[0154] Furthermore, the protective layer 131 may have an organic film. For example, the protective layer 131 may have both an organic film and an inorganic film.

[0155] The protective layer 131 may have a two-layer structure formed using different film deposition methods. Specifically, the first layer of the protective layer 131 may be formed using the ALD method, and the second layer of the protective layer 131 may be formed using the sputtering method.

[0156] In the display device of this embodiment, the upper edge of the pixel electrode is not covered by an insulating layer. Therefore, the spacing between adjacent light-emitting devices can be made extremely narrow. Consequently, a high-definition or high-resolution display device can be achieved.

[0157] In this specification, devices fabricated using a metal mask or an FMM (Fine Metal Mask, a high-resolution metal mask) may be referred to as MM (Metal Mask) structured devices. Furthermore, in this specification, devices fabricated without using a metal mask or an FMM may be referred to as MML (Metal Maskless) structured devices.

[0158] In this specification, a structure in which different light-emitting layers are created or painted for each color of light-emitting device (here, blue (B), green (G), and red (R)) may be referred to as an SBS (Side By Side) structure. The SBS structure allows for the optimization of materials and configuration for each light-emitting device, thus increasing the freedom of material and configuration selection and making it easier to improve brightness and reliability.

[0159] Furthermore, in this specification, a light-emitting device capable of emitting white light may be referred to as a white light-emitting device. A white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0160] Furthermore, light-emitting devices can be broadly classified into single structures and tandem structures. A single-structure device has one light-emitting unit between a pair of electrodes, and it is preferable that the light-emitting unit includes one or more light-emitting layers. When obtaining white light emission using two light-emitting layers, the light-emitting layers should be selected such that their emission colors are complementary. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary, a configuration that emits white light as a whole can be obtained. Also, when obtaining white light emission using three or more light-emitting layers, the combination of the emission colors of the three or more light-emitting layers should result in a configuration that emits white light as a whole.

[0161] A tandem device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, the light from the light-emitting layers of the multiple light-emitting units should be combined to produce white light emission. The configuration for obtaining white light emission is the same as for a single-structure device. In a tandem device, it is preferable to provide a charge-generating layer between the multiple light-emitting units.

[0162] Furthermore, when comparing the aforementioned white light-emitting devices (single or tandem structure) with SBS structure light-emitting devices, SBS structure light-emitting devices can consume less power than white light-emitting devices. If you want to keep power consumption low, it is preferable to use SBS structure light-emitting devices. On the other hand, white light-emitting devices are preferable because their manufacturing process is simpler than that of SBS structure light-emitting devices, which can lead to lower manufacturing costs or higher manufacturing yields.

[0163] The display device of this embodiment can reduce the distance between light-emitting devices. Specifically, the distance between light-emitting devices, the distance between EL layers, or the distance between pixel electrodes can be less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 10 nm or less. In other words, the distance between the side surface of the first layer 113a and the side surface of the second layer 113b, or the distance between the side surface of the second layer 113b and the side surface of the third layer 113c, has a region of 1 μm or less, preferably a region of 0.5 μm (500 nm) or less, and more preferably a region of 100 nm or less.

[0164] A light-shielding layer may be provided on the surface of the substrate 120 facing the resin layer 122. Various optical components can also be placed on the outside of the substrate 120. Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (such as diffusion films), anti-reflective layers, and light-collecting films. Furthermore, an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, and an impact-absorbing layer may also be placed on the outside of the substrate 120.

[0165] The substrate 120 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, etc. The substrate on the side that extracts light from the light-emitting device should be made of a material that transmits the light. If a flexible material is used for the substrate 120, the flexibility of the display device can be increased, and a flexible display can be realized. Alternatively, a polarizing plate may be used as the substrate 120.

[0166] As the substrate 120, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. may be used. Glass with a thickness sufficient to provide flexibility may also be used as the substrate 120.

[0167] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy for the substrate of the display device. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence).

[0168] For substrates with high optical isotropy, the absolute value of the retardation (phase difference) is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0169] Examples of films with high optical isotropy include triacetylcellulose (TAC, also known as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0170] Furthermore, when using a film as the substrate, the film may absorb water, potentially causing wrinkles or other shape changes in the display panel. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferable to use a film with a water absorption rate of 0.1% or less, and even more preferable to use a film with a water absorption rate of 0.01% or less.

[0171] As the resin layer 122, various types of curing adhesives can be used, such as UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0172] Materials that can be used for conductive layers such as the gate, source, and drain of transistors, as well as various wirings and electrodes that constitute display devices, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys mainly composed of these metals. Films containing these materials can be used as single layers or in a multilayer structure.

[0173] Furthermore, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene can be used as the light-transmitting conductive material. Alternatively, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metallic materials, can be used. Alternatively, nitrides of such metallic materials (e.g., titanium nitride) may be used. When using metallic materials or alloy materials (or their nitrides), it is preferable to make them thin enough to be light-transmitting. In addition, a laminated film of the above materials can be used as a conductive layer. For example, using a laminated film of a silver-magnesium alloy and indium tin oxide is preferable because it can enhance conductivity. These can also be used as conductive layers for various wirings and electrodes that constitute a display device, and as conductive layers (conductive layers that function as pixel electrodes or common electrodes) in light-emitting devices.

[0174] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide, and aluminum oxide.

[0175] [Pixel layout] Next, we will describe a pixel layout different from Figure 1A. There are no particular limitations on the arrangement of subpixels, and various methods can be applied. Examples of subpixel arrangements include stripe arrangements, S-stripe arrangements, matrix arrangements, delta arrangements, Bayer arrangements, and pentile arrangements.

[0176] Furthermore, the top surface shape of a sub-pixel can be, for example, a polygon such as a triangle, quadrilateral (including rectangles and squares), or pentagon, or a polygon with rounded corners, or an ellipse or a circle. Here, the top surface shape of a sub-pixel corresponds to the top surface shape of the light-emitting region of the light-emitting device.

[0177] The pixel 110 shown in Figure 2A has an S-stripe array applied to it. The pixel 110 shown in Figure 2A is composed of three subpixels: subpixels 110a, 110b, and 110c. For example, as shown in Figure 3A, subpixel 110a may be a blue subpixel B, subpixel 110b may be a red subpixel R, and subpixel 110c may be a green subpixel G.

[0178] The pixel 110 shown in Figure 2B includes a sub-pixel 110a with a roughly trapezoidal top surface shape with rounded corners, a sub-pixel 110b with a roughly triangular top surface shape with rounded corners, and a sub-pixel 110c with a roughly quadrilateral or hexagonal top surface shape with rounded corners. Furthermore, sub-pixel 110a has a larger light-emitting area than sub-pixel 110b. Thus, the shape and size of each sub-pixel can be determined independently. For example, the size of a sub-pixel can be reduced to a level that provides a more reliable light-emitting device. For example, as shown in Figure 3B, sub-pixel 110a may be a green sub-pixel G, sub-pixel 110b may be a red sub-pixel R, and sub-pixel 110c may be a blue sub-pixel B.

[0179] A Pentile array is applied to pixels 124a and 124b shown in Figure 2C. Figure 2C shows an example in which pixels 124a having subpixels 110a and 110b and pixels 124b having subpixels 110b and 110c are arranged alternately. For example, as shown in Figure 3C, subpixel 110a may be a red subpixel R, subpixel 110b may be a green subpixel G, and subpixel 110c may be a blue subpixel B.

[0180] Pixels 124a and 124b shown in Figures 2D and 2E utilize a delta array. Pixel 124a has two subpixels (subpixels 110a and 110b) in the top row (1st row) and one subpixel (subpixel 110c) in the bottom row (2nd row). Pixel 124b has one subpixel (subpixel 110c) in the top row (1st row) and two subpixels (subpixels 110a and 110b) in the bottom row (2nd row). For example, as shown in Figure 3D, subpixel 110a may be a red subpixel R, subpixel 110b a green subpixel G, and subpixel 110c a blue subpixel B.

[0181] Figure 2D shows an example where each subpixel has a roughly square top shape with rounded corners, and Figure 2E shows an example where each subpixel has a circular top shape.

[0182] Figure 2F shows an example where the subpixels of each color are arranged in a zigzag pattern. Specifically, in a top view, the upper edges of two subpixels aligned in the column direction (for example, subpixels 110a and 110b, or subpixels 110b and 110c) are offset. For example, as shown in Figure 3E, subpixel 110a could be the red subpixel R, subpixel 110b could be the green subpixel G, and subpixel 110c could be the blue subpixel B.

[0183] In photolithography, the finer the pattern being processed, the more significant the effects of light diffraction become. This compromises the fidelity of the transfer of the photomask pattern through exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, patterns with rounded corners are likely to be formed. Consequently, the top surface shape of subpixels may be a polygon with rounded corners, an ellipse, or a circle.

[0184] Furthermore, in a method for manufacturing a display device according to one aspect of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the EL layer material and the curing temperature of the resist material, the curing of the resist film may be insufficient. A resist film that is not sufficiently cured may take a shape that deviates from the desired shape during processing. As a result, the top surface shape of the EL layer may become a polygon with rounded corners, an ellipse, or a circle. For example, if an attempt is made to form a resist mask with a square top surface, a resist mask with a circular top surface may be formed, resulting in a circular top surface shape for the EL layer.

[0185] Furthermore, in order to achieve the desired shape of the upper surface of the EL layer, a technique (OPC (Optical Proximity Correction) technique) may be used to pre-correct the mask pattern so that the design pattern and the transferred pattern match. Specifically, in the OPC technique, a correction pattern is added to the corners of the shape on the mask pattern.

[0186] Furthermore, even in the pixel 110 to which the stripe arrangement shown in Figure 1A is applied, for example, as shown in Figure 3F, sub-pixel 110a can be a red sub-pixel R, sub-pixel 110b can be a green sub-pixel G, and sub-pixel 110c can be a blue sub-pixel B.

[0187] As shown in Figures 4A to 4H, a pixel can be configured to have four types of subpixels.

[0188] The pixels 110 shown in Figures 4A to 4C have a stripe arrangement applied to them.

[0189] Figure 4A shows an example where each subpixel has a rectangular top surface shape, Figure 4B shows an example where each subpixel has a top surface shape formed by connecting two semicircles and a rectangle, and Figure 4C shows an example where each subpixel has an elliptical top surface shape.

[0190] Pixel 110, shown in Figures 4D to 4F, has a matrix array applied to it.

[0191] Figure 4D shows an example where each subpixel has a square top surface shape, Figure 4E shows an example where each subpixel has a roughly square top surface shape with rounded corners, and Figure 4F shows an example where each subpixel has a circular top surface shape.

[0192] Figures 4G and 4H show an example where one pixel 110 is composed of 2 rows and 3 columns.

[0193] Pixel 110, shown in Figure 4G, has three subpixels (subpixels 110a, 110b, and 110c) in the top row (row 1) and one subpixel (subpixel 110d) in the bottom row (row 2). In other words, pixel 110 has subpixel 110a in the left column (column 1), subpixel 110b in the middle column (column 2), subpixel 110c in the right column (column 3), and subpixel 110d across these three columns.

[0194] As shown in Figure 4H, pixel 110 has three subpixels (subpixels 110a, 110b, and 110c) in the top row (1st row) and three subpixels 110d in the bottom row (2nd row). In other words, pixel 110 has subpixels 110a and 110d in the left column (1st column), subpixels 110b and 110d in the middle column (2nd column), and subpixels 110c and 110d in the right column (3rd column). As shown in Figure 4H, by aligning the arrangement of subpixels in the top row and the bottom row, it becomes possible to efficiently remove dust and other debris that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided.

[0195] The pixel 110 shown in Figures 4A to 4H is composed of four subpixels: subpixels 110a, 110b, 110c, and 110d. Each subpixel 110a, 110b, 110c, and 110d has a light-emitting device that emits light of a different color. Examples of subpixels 110a, 110b, 110c, and 110d include subpixels of four colors: R, G, B, and white (W); subpixels of four colors: R, G, B, and Y; or subpixels that emit red, green, blue, and infrared light. For example, as shown in Figures 5A to 5D, subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and white subpixels, respectively.

[0196] A display device according to one aspect of the present invention may have a light-receiving device in each pixel.

[0197] Of the four types of subpixels that the pixel 110 shown in Figures 4A to 4H has, three may be configured to have light-emitting devices and the remaining one to have a light-receiving device.

[0198] For example, a pn-type or pin-type photodiode can be used as the light-receiving device. The light-receiving device functions as a photoelectric conversion device (also called a photoelectric conversion element) that detects light incident on it and generates an electric charge. The amount of charge generated from the light-receiving device is determined by the amount of light incident on it.

[0199] In particular, it is preferable to use an organic photodiode having a layer containing an organic compound as the light-receiving device. Organic photodiodes can be easily made thinner, lighter, and larger in area, and because they offer a high degree of freedom in shape and design, they can be applied to various display devices.

[0200] In one aspect of the present invention, an organic EL device is used as the light-emitting device, and an organic photodiode is used as the light-receiving device. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be incorporated into a display device using an organic EL device.

[0201] 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, one of the pair of electrodes may be referred to as the pixel electrode and the other as the common electrode.

[0202] For example, sub-pixels 110a, 110b, and 110c may be sub-pixels of three colors: R, G, and B, and sub-pixel 110d may be a sub-pixel having a light-receiving device.

[0203] In a photodetector, one electrode functions as the anode and the other as the cathode. The following explanation uses the example where the pixel electrode functions as the anode and the common electrode functions as the cathode. The photodetector can detect incoming light, generate an electric charge, and extract it as an electric current by applying a reverse bias between the pixel electrode and the common electrode. Alternatively, the pixel electrode may function as the cathode and the common electrode as the anode.

[0204] For the light-receiving device as well, the same manufacturing method as that of the light-emitting device can be applied. The island-shaped active layer (also referred to as a photoelectric conversion layer) of the light-receiving device is not formed using a fine metal mask, but is formed by processing after forming a film serving as the active layer on one surface. Therefore, the island-shaped active layer can be formed with a uniform thickness. Further, 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, and the reliability of the light-receiving device can be enhanced.

[0205] Here, the layers common to the light-receiving device and the light-emitting device may have different functions in the light-emitting device and the light-receiving device. In this specification, components may be named based on their functions in the light-emitting device. For example, the hole injection layer functions as a hole injection layer in the light-emitting device and as a hole transport layer in the light-receiving device. Similarly, the electron injection layer functions as an electron injection layer in the light-emitting device and as an electron transport layer in the light-receiving device. Also, the layers common to the light-receiving device and the light-emitting device may have the same functions in the light-emitting device and the light-receiving device. The hole transport layer functions as a hole transport layer in both the light-emitting device and the light-receiving device, and the electron transport layer functions as an electron transport layer in both the light-emitting device and the light-receiving device.

[0206] The active layer of the light-receiving device contains a semiconductor. Examples of the semiconductor include inorganic semiconductors such as silicon and organic semiconductors containing organic compounds. In the present embodiment, an example using an organic semiconductor 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 (for example, vacuum evaporation method), and the manufacturing equipment can be shared.

[0207] Examples of the material of the n-type semiconductor in the active layer include fullerenes (for example, C 60 fullerene, C 70Examples include electron-accepting organic semiconductor materials such as fullerenes and fullerene derivatives. Fullerenes have a shape like a soccer ball, and this shape is energetically stable. Both the HOMO and LUMO levels of fullerenes are deep (low). Because the LUMO level of fullerenes is deep, they have extremely high electron-accepting properties. Normally, when π-electron conjugation (resonance) spreads out in a plane, as in benzene, electron-donating properties increase, but because fullerenes have a spherical shape, they have high electron-accepting properties despite the large spread of π-electrons. High electron-accepting properties allow for fast and efficient charge separation, making them useful as photodetectors. 60 Fullerene, C 70 Both fullerenes and C have a broad absorption band in the visible light region, and C 70 Fullerenes are C 60 Compared to fullerenes, it is preferable because it has a larger π-electron conjugation system and a broad absorption band in the long-wavelength region. Other examples of fullerene derivatives include [6,6]-Phenyl-C71-butyric acid methyl ester (abbreviated as PC70BM), [6,6]-Phenyl-C61-butyric acid methyl ester (abbreviated as PC60BM), and 1',1'',4',4''-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2'',3''][5,6]fullerene-C60 (abbreviated as ICBA).

[0208] Furthermore, examples of n-type semiconductor materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, naphthalene derivatives, anthracene derivatives, coumarin derivatives, rhodamine derivatives, triazine derivatives, and quinone derivatives.

[0209] Examples of p-type semiconductor materials for the active layer include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin(II) phthalocyanine (SnPc), and quinacridone.

[0210] Furthermore, examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, and compounds having an aromatic amine skeleton. In addition, examples of p-type semiconductor materials include naphthalene derivatives, anthracene derivatives, pyrene derivatives, triphenylene derivatives, fluorene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, indrocarbazole derivatives, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, quinacridone derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polythiophene derivatives.

[0211] The HOMO level of electron-donating organic semiconductor materials is preferably shallower (higher) than the HOMO level of electron-accepting organic semiconductor materials. The LUMO level of electron-donating organic semiconductor materials is preferably shallower (higher) than the LUMO level of electron-accepting organic semiconductor materials.

[0212] It is preferable to use spherical fullerenes as electron-accepting organic semiconductor materials and organic semiconductor materials with a near-planar shape as electron-donating organic semiconductor materials. Molecules with similar shapes tend to aggregate, and when molecules of the same type aggregate, their molecular orbital energy levels are close, which can improve carrier transport.

[0213] For example, the active layer is preferably formed by co-depositing an n-type semiconductor and a p-type semiconductor. Alternatively, the active layer may be formed by stacking an n-type semiconductor and a p-type semiconductor.

[0214] The photodetector may further include layers other than the active layer, such as a material with high hole transport properties, a material with high electron transport properties, or a bipolar material (a material with high electron and hole transport properties). Furthermore, it may also further include layers containing a material with high hole injection properties, a hole blocking material, a material with high electron injection properties, an electron blocking material, etc.

[0215] The light-receiving device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-receiving device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0216] For example, polymer compounds such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS), and inorganic compounds such as molybdenum oxide and copper iodide (CuI) can be used as hole transport materials. In addition, inorganic compounds such as zinc oxide (ZnO) can be used as electron transport materials.

[0217] Furthermore, the active layer can use polymer compounds such as Poly[[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c']dithiophene-1,3-diyl]]polymer (abbreviated as PBDB-T) or PBDB-T derivatives, which function as donors. For example, a method of dispersing the acceptor material in PBDB-T or a PBDB-T derivative can be used.

[0218] Furthermore, the active layer may contain a mixture of three or more materials. For example, to broaden the absorption wavelength range, a third material may be mixed with an n-type semiconductor material and a p-type semiconductor material. In this case, the third material may be a low-molecular-weight compound or a high-molecular-weight compound.

[0219] In a display device having light-emitting and light-receiving devices in its pixels, the pixels have a light-receiving function, allowing for the detection of contact or proximity of an object while displaying an image. For example, in addition to displaying an image with all of the subpixels of the display device, some subpixels can emit light as a light source, some other subpixels can perform light detection, and the remaining subpixels can display an image.

[0220] A display device according to one aspect of the present invention has a display unit in which light-emitting devices are arranged in a matrix, and an image can be displayed on the display unit. Furthermore, light-receiving devices are arranged in a matrix on the display unit, and the display unit has an image display function, as well as one or both of an imaging function and a sensing function. The display unit can be used as an image sensor or a touch sensor. That is, by detecting light on the display unit, an image can be captured, or the proximity or contact of an object (such as a finger, hand, or pen) can be detected. Moreover, in a display device according to one aspect of the present invention, the light-emitting devices can be used as a light source for a sensor. Therefore, it is not necessary to provide a separate light-receiving unit and light source from the display device, and the number of components in the electronic device can be reduced.

[0221] In one embodiment of the present invention, when an object reflects (or scatters) light emitted by a light-emitting device of the display unit, a light-receiving device can detect the reflected light (or scattered light), thus enabling image capture or touch detection even in dark places.

[0222] When a light-receiving device is used as an image sensor, the display device can capture an image using the light-receiving device. For example, the display device of this embodiment can be used as a scanner.

[0223] For example, an image sensor can be used to acquire biometric data such as fingerprints and palm prints. In other words, a biometric authentication sensor can be built into the display device. By having the display device incorporate the biometric authentication sensor, the number of components in the electronic device can be reduced compared to when a separate biometric authentication sensor is provided, enabling miniaturization and weight reduction of the electronic device.

[0224] Furthermore, when a light-receiving device is used as a touch sensor, the display device can use the light-receiving device to detect the proximity or contact of an object.

[0225] The pixels shown in Figures 6A and 6B have sub-pixels G, B, R, and PS.

[0226] The pixels shown in Figure 6A have a stripe array applied. The pixels shown in Figure 6B have a matrix array applied.

[0227] The pixels shown in Figures 6C and 6D have sub-pixels G, B, R, PS, and IRS.

[0228] Figures 6C and 6D show an example where one pixel is arranged across two rows and three columns. The top row (first row) has three subpixels (subpixel G, subpixel B, and subpixel R). In Figure 6C, the bottom row (second row) has three subpixels (one subpixel PS and two subpixels IRS). On the other hand, in Figure 6D, the bottom row (second row) has two subpixels (one subpixel PS and one subpixel IRS). As shown in Figure 6C, by aligning the arrangement of subpixels in the top and bottom rows, it becomes possible to efficiently remove dust and other debris that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided. Note that the layout of subpixels is not limited to the configuration shown in Figures 6A to 6D.

[0229] Sub-pixel R has a light-emitting device that emits red light. Sub-pixel G has a light-emitting device that emits green light. Sub-pixel B has a light-emitting device that emits blue light.

[0230] Sub-pixels PS and IRS each have a light-receiving device. The wavelength of light detected by sub-pixels PS and IRS is not particularly limited.

[0231] In Figure 6C, the two subpixel IRS may each have an independent photodetector, or they may share a single photodetector. In other words, the pixel 110 shown in Figure 6C can be configured to have one photodetector for the subpixel PS and one or two photodetectors for the subpixel IRS.

[0232] The light-receiving area of ​​the sub-pixel PS is smaller than that of the sub-pixel IRS. A smaller light-receiving area results in a narrower imaging range, which helps suppress blurring in the image and improves resolution. Therefore, using sub-pixel PS allows for higher-definition or higher-resolution imaging compared to using sub-pixel IRS. For example, sub-pixel PS can be used to capture images for personal authentication, such as fingerprints, palm prints, irises, pulse patterns (including vein and artery patterns), or faces.

[0233] The light-receiving device in the sub-pixel PS preferably detects visible light, and more preferably detects one or more of the following colors: blue, violet, blue-violet, green, yellow-green, yellow, orange, and red. Alternatively, the light-receiving device in the sub-pixel PS may also detect infrared light.

[0234] Furthermore, sub-pixel IRS can be used in touch sensors (also called direct touch sensors) or near-touch sensors (also called hover sensors, hover-touch sensors, non-contact sensors, or touchless sensors). Depending on the application, the wavelength of light detected by the sub-pixel IRS can be appropriately determined. For example, it is preferable for the sub-pixel IRS to detect infrared light. This enables touch detection even in dark places.

[0235] Here, the touch sensor or near-touch sensor can detect the proximity or contact of an object (such as a finger, hand, or pen).

[0236] A touch sensor can detect an object by making direct contact with the display device. A near-touch sensor can detect an object even if the object does not touch the display device. For example, it is preferable that the display device can detect an object when the distance between the display device and the object is in the range of 0.1 mm to 300 mm, preferably 3 mm to 50 mm. With this configuration, it becomes possible to operate the display device without the object directly touching it, in other words, it becomes possible to operate the display device without contact (touchless). With the above configuration, the risk of the display device becoming dirty or scratched can be reduced, or it becomes possible to operate the display device without the object directly touching any dirt (e.g., dust or viruses) attached to the display device.

[0237] Furthermore, a display device according to one aspect of the present invention can have a variable refresh rate. For example, power consumption can be reduced by adjusting the refresh rate according to the content displayed on the display device (for example, adjusting within a range of 1 Hz to 240 Hz). In addition, the drive frequency of the touch sensor or near touch sensor may be changed according to the refresh rate. For example, if the refresh rate of the display device is 120 Hz, the drive frequency of the touch sensor or near touch sensor can be set to a frequency higher than 120 Hz (typically 240 Hz). This configuration makes it possible to achieve low power consumption and to increase the response speed of the touch sensor or near touch sensor.

[0238] The display device 100 shown in Figures 6E to 6G has a layer 353 having a light-receiving device, a functional layer 355, and a layer 357 having a light-emitting device between substrate 351 and substrate 359.

[0239] The functional layer 355 includes circuits for driving a light-receiving device and circuits for driving a light-emitting device. The functional layer 355 may be equipped with switches, transistors, capacitors, resistors, wiring, terminals, etc. However, when the light-emitting and light-receiving devices are driven using a passive matrix system, the configuration may omit switches and transistors.

[0240] For example, as shown in Figure 6E, in layer 357 which has a light-emitting device, the light emitted by the light-emitting device is reflected by a finger 352 that is in contact with the display device 100, and the light-receiving device in layer 353 which has a light-receiving device detects the reflected light. This makes it possible to detect that the finger 352 has come into contact with the display device 100. Alternatively, as shown in Figures 6F and 6G, the device may have a function to detect or image objects that are close to (but not in contact with) the display device. Figure 6F shows an example of detecting a person's finger, and Figure 6G shows an example of detecting information around, on the surface of, or inside a person's eye (such as the number of blinks, eyeball movements, and eyelid movements).

[0241] By equipping a single pixel with two types of light-receiving devices, it becomes possible to add two additional functions to the display function, thus enabling the multi-functionality of the display device.

[0242] Furthermore, in order to perform high-resolution imaging, it is preferable that sub-pixels PS be provided on all pixels of the display device. On the other hand, sub-pixels IRS used in touch sensors or near-touch sensors do not require the same high precision as detection using sub-pixels PS, so it is sufficient to provide them on only some of the pixels of the display device. By reducing the number of sub-pixels IRS in the display device to fewer than the number of sub-pixels PS, the detection speed can be increased.

[0243] As described above, one embodiment of the present invention enables the multi-functionalization of a display device by equipping a single pixel with two types of light-receiving devices, thereby adding two additional functions to the display function. For example, it can realize a high-definition imaging function and a sensing function such as a touch sensor or near-touch sensor. Furthermore, the functionality of the display device can be further increased by combining a pixel equipped with two types of light-receiving devices with a pixel with a different configuration. For example, a pixel having an infrared light-emitting device or various sensor devices can be used.

[0244] [Example 1 of a method for manufacturing a display device] Next, an example of a method for manufacturing a display device will be explained using Figures 7 to 14. Figures 7A to 7F are top views showing the method for manufacturing a display device. Figures 8A to 8C show the cross-sectional view between the dashed-dotted line X1-X2 and the cross-sectional view between Y1-Y2 in Figure 1A side by side. Figures 9 to 14 are similar to Figure 8.

[0245] Thin films (insulating films, semiconductor films, and conductive films, etc.) that constitute display devices can be formed using sputtering, CVD, vacuum deposition, pulsed laser deposition (PLD), ALD, and other methods. CVD methods include PECVD and thermal CVD. One type of thermal CVD is metal-organic chemical vapor deposition (MOCVD).

[0246] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife coating, slit coating, roll coating, curtain coating, and knife coating.

[0247] In particular, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet can be used to fabricate light-emitting devices. Examples of vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, as well as chemical vapor deposition (CVD). Functional layers included in the EL layer (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, etc.) can be formed by vapor deposition (vacuum deposition, etc.), coating methods (dip coating, die coating, bar coating, spin coating, spray coating, etc.), and printing methods (inkjet, screen printing, offset printing, flexographic printing, gravure, or microcontact printing, etc.).

[0248] Furthermore, when processing the thin film that constitutes the display device, photolithography or the like can be used. Alternatively, the thin film may be processed by nanoimprint lithography, sandblasting, lift-off lithography, or the like. In addition, island-shaped thin films may be directly formed by a film deposition method using a shielding mask such as a metal mask.

[0249] There are two main methods of photolithography. One method involves forming a resist mask on the thin film to be processed, then processing the thin film by etching or other means, and removing the resist mask. The other method involves forming a photosensitive thin film, then exposing and developing it to process the thin film into the desired shape.

[0250] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture thereof. Other options include ultraviolet light, KrF laser light, or ArF laser light. Exposure may also be performed using immersion lithography. Furthermore, extreme ultraviolet (EUV) light or X-rays may be used as the light source for exposure. An electron beam can also be used instead of the light source. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because it allows for extremely fine processing. Note that a photomask is not required when exposure is performed by scanning a beam such as an electron beam.

[0251] For etching thin films, methods such as dry etching, wet etching, and sandblasting can be used.

[0252] First, as shown in Figure 8A, conductive layers 111a, 111b, and 111c are formed on layer 101 containing the transistor. Then, layer 128 is formed to fill the recesses of conductive layers 111a, 111b, and 111c. Next, conductive layers 112a, 112b, and 112c are formed on conductive layers 111a, 111b, and 111c, and on layer 128. Conductive layers 126a, 126b, and 126c are formed on conductive layers 112a, 112b, and 112c, and conductive layers 129a, 129b, and 129c are formed on conductive layers 126a, 126b, and 126c.

[0253] It is preferable that the conductive layers 112a, 112b, and 112c are provided so as to cover the sides of the conductive layers 111a, 111b, and 111c, respectively. In other words, it is preferable that the edges of the conductive layers 112a, 112b, and 112c are located outside the edges of the conductive layers 111a, 111b, and 111c. Alternatively, the edges of the conductive layers 112a, 112b, and 112c may coincide with the edges of the conductive layers 111a, 111b, and 111c. Alternatively, they may be located inside the edges of the conductive layers 111a, 111b, and 111c.

[0254] 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. That is, 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. Or they may be located inside the ends of the conductive layers 112a, 112b, and 112c.

[0255] The conductive layers 129a, 129b, and 129c are preferably provided so as to cover the side surfaces of the conductive layers 126a, 126b, and 126c, respectively. That is, the ends of the conductive layers 129a, 129b, and 129c are preferably located outside the ends of the conductive layers 126a, 126b, and 126c. Alternatively, the ends of the conductive layers 129a, 129b, and 129c may coincide with the ends of the conductive layers 126a, 126b, and 126c. Or they may be located inside the ends of the conductive layers 126a, 126b, and 126c.

[0256] Hereinafter, mainly the conductive layers 111a, 112a, 126a, and 129a will be taken as examples for explanation, but the same applies to the conductive layers 111b, 112b, 126b, 129b, and the conductive layers 111c, 112c, 126c, 129c.

[0257] In this embodiment, an example in which the positions of the respective ends of the conductive layers 111a, 112a, 126a, and 129a are different is shown, but it is not limited thereto. For example, at least two of the films that become the conductive layers 111a, 112a, 126a, and 129a may be processed in the same process or processed using the same mask pattern. This makes it possible to reduce the number of processes or the number of masks, which is preferable. Among the conductive layers 111a, 112a, 126a, and 129a, the layers formed by processing using the same process or the same mask pattern have ends that are aligned or approximately aligned. In other words, the upper surface shapes of at least two of the conductive layers 111a, 112a, 126a, and 129a may be the same or approximately the same.

[0258] Furthermore, the connection portion 140 is provided with a conductive layer formed from the same material and using the same process as at least one of the conductive layers 111a, 112a, 126a, and 129a. In this embodiment, the conductive layer 123 provided in the connection portion 140 is shown as having three conductive layers formed from the same material and using the same process as conductive layers 111a, 112a, and 129a. The conductive layer 123 may be a single-layer structure or a laminated structure.

[0259] Then, a first layer 113A is formed on the conductive layers 129a, 129b, and 129c, a first sacrificial layer 118A is formed on the first layer 113A, and a second sacrificial layer 119A is formed on the first sacrificial layer 118A.

[0260] As shown in Figure 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 inward (towards the display portion) than the end of the first sacrificial layer 118A. For example, by using a mask for defining the film deposition area (also called an area mask or rough metal mask, to distinguish it from a fine metal mask), the areas to be film-deposited by the first layer 113A, the first sacrificial layer 118A, and the second sacrificial layer 119A can be changed. In one embodiment of the present invention, a light-emitting device is formed using a resist mask, but by combining it with an area mask as described above, a light-emitting device can be manufactured in a relatively simple process.

[0261] The conductive layers 111a, 112a, 126a, and 129a can be configured to accept the same configurations as those applicable to the pixel electrodes described above. For example, sputtering or vacuum deposition can be used to form the conductive layers 111a, 112a, 126a, and 129a.

[0262] The first layer 113A is the layer that will later become the first layer 113a. Therefore, the configuration applicable to the first layer 113a described above can be applied to it. The first layer 113A can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating. It is preferable to form the first layer 113A using vapor deposition. In film formation using vapor deposition, a premixed material may be used. In this specification, a premixed material is a composite material obtained by pre-combining or mixing multiple materials.

[0263] The first sacrificial layer 118A and the second sacrificial layer 119A use films that have high resistance to processing conditions, such as the first layer 113A and the second layer 113B and third layer 113C formed in later processes, specifically films that have a high selectivity ratio for etching with various EL layers.

[0264] For the formation of the first sacrificial layer 118A and the second sacrificial layer 119A, for example, sputtering, ALD (including thermal ALD and PEALD), CVD, or vacuum deposition can be used. It is preferable that the first sacrificial layer 118A, which is formed in contact with the EL layer, is formed using a method that causes less damage to the EL layer than the second sacrificial layer 119A. For example, it is preferable to form the first sacrificial layer 118A using ALD or vacuum deposition rather than sputtering. Furthermore, the first sacrificial layer 118A and the second sacrificial layer 119A are formed at a temperature lower than the heat resistance temperature of the EL layer (typically 200°C or lower, preferably 100°C or lower, and more preferably 80°C or lower).

[0265] It is preferable to use films that can be removed by wet etching for the first sacrificial layer 118A and the second sacrificial layer 119A. By using wet etching, the damage inflicted on the first layer 113A during processing of the first sacrificial layer 118A and the second sacrificial layer 119A can be reduced compared to when using dry etching.

[0266] Furthermore, it is preferable to use a film for the first sacrificial layer 118A that has a high etching selectivity ratio with the second sacrificial layer 119A.

[0267] In the manufacturing process of the display device according to this embodiment, it is desirable that each layer constituting the EL layer (hole injection layer, hole transport layer, light-emitting layer, and electron transport layer, etc.) is difficult to process, and that the various sacrificial layers are difficult to process during the manufacturing process of each layer constituting the EL layer. It is desirable to select the material and manufacturing method of the sacrificial layer and the manufacturing method of the EL layer taking these factors into consideration.

[0268] In this embodiment, an example is shown in which the sacrificial layer is formed with a two-layer structure consisting of a first sacrificial layer and a second sacrificial layer. However, the sacrificial layer may be a single-layer structure or a laminated structure of three or more layers.

[0269] For the first sacrificial layer 118A and the second sacrificial layer 119A, for example, inorganic films such as metal films, alloy films, metal oxide films, semiconductor films, and inorganic insulating films can be used, respectively.

[0270] The first sacrificial layer 118A and the second sacrificial layer 119A can be made of metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metallic materials. In particular, it is preferable to use low-melting-point materials such as aluminum or silver. It is preferable to use a metallic material capable of shielding ultraviolet light in one or both of the first sacrificial layer 118A and the second sacrificial layer 119A, as this can suppress irradiation of the EL layer with ultraviolet light and thus suppress deterioration of the EL layer.

[0271] Furthermore, metal oxides such as In-Ga-Zn oxide can be used for the first sacrificial layer 118A and the second sacrificial layer 119A. For example, an In-Ga-Zn oxide film can be formed as the first sacrificial layer 118A or the second sacrificial layer 119A using a sputtering method. In addition, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc. can be used. Alternatively, indium tin oxide containing silicon can also be used.

[0272] In addition, element M (where M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) may be used instead of gallium.

[0273] Furthermore, various inorganic insulating films that can be used in the protective layer 131 can be used as the first sacrificial layer 118A and the second sacrificial layer 119A. In particular, oxide insulating films are preferred because they have higher adhesion to the EL layer compared with nitride insulating films. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used as the first sacrificial layer 118A and the second sacrificial layer 119A. For example, an aluminum oxide film can be formed as the first sacrificial layer 118A or the second sacrificial layer 119A using the ALD method. Using the ALD method is preferable because it reduces damage to the substrate (especially the EL layer).

[0274] For example, as the first sacrificial layer 118A, an inorganic insulating film (e.g., aluminum oxide film) formed using the ALD method can be used, and as the second sacrificial layer 119A, an In-Ga-Zn oxide film formed using the sputtering method can be used. Alternatively, as the first sacrificial layer 118A, an inorganic insulating film (e.g., aluminum oxide film) formed using the ALD method can be used, and as the second sacrificial layer 119A, an aluminum film or a tungsten film formed using the sputtering method can be used.

[0275] As the first sacrificial layer 118A and the second sacrificial layer 119A, a material that can be dissolved in a chemically stable solvent may be used for at least the film located at the uppermost part of the first layer 113A. In particular, a material that can be dissolved in water or alcohol can be preferably used for the first sacrificial layer 118A or the second sacrificial layer 119A. When forming such a material into a film, it is preferable to perform a heat treatment for evaporating the solvent after coating in a wet film-forming method in a state of being dissolved in a solvent such as water or alcohol. At this time, by performing the heat treatment in a reduced-pressure atmosphere, the solvent can be removed at a low temperature and in a short time, so that thermal damage to the EL layer can be reduced, which is preferable.

[0276] The first sacrificial layer 118A and the second sacrificial layer 119A may be formed using a wet film-forming method such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, knife coating, etc.

[0277] For the first sacrificial layer 118A and the second sacrificial layer 119A, an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin may be used.

[0278] Next, as shown in Figure 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), followed by exposure and development.

[0279] The resist mask may be made using either a positive-type resist material or a negative-type resist material.

[0280] The resist mask 190a is provided in a position that overlaps with the region that will later become the subpixel 110a. As shown in Figure 7A, it is preferable that the resist mask 190a provides one island-shaped pattern for each subpixel 110a. Alternatively, as shown in Figure 7D, the resist mask 190a may form one band-shaped pattern for multiple subpixels 110a arranged in a row (arranged in the Y direction in Figure 7D).

[0281] In this case, it is preferable to form the resist mask 190a such that its edge is located outside the edge of the conductive layer 129a. This allows the edge of the first layer 113a, which will be formed later, to be located outside the edge of the conductive layer 129a.

[0282] Furthermore, it is preferable to also provide the resist mask 190a in a position that overlaps with the connection portion 140. This helps to suppress damage to the conductive layer 123 during the manufacturing process of the display device.

[0283] Next, as shown in Figure 8B, a resist mask 190a is used to remove a portion of the second sacrificial layer 119A, thereby forming 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.

[0284] When etching the second sacrificial layer 119A, it is preferable to use etching conditions with a high selectivity ratio so that the first sacrificial layer 118A is not removed by the etching. Furthermore, since the EL layer is not exposed during the processing of the second sacrificial layer 119A, there is a wider range of processing methods to choose from than for the processing of the first sacrificial layer 118A. Specifically, when processing the second sacrificial layer 119A, even if an etching gas containing oxygen is used, the deterioration of the EL layer can be further suppressed.

[0285] Subsequently, the resist mask 190a is removed. For example, the resist mask 190a can be removed by ashing using oxygen plasma. Alternatively, oxygen gas and noble gases (also called rare gases) such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He may be used. Alternatively, the resist mask 190a may be removed by wet etching. In this case, since the first sacrificial layer 118A is located on the outermost surface and the first layer 113A is not exposed, damage to the first layer 113A can be suppressed during the resist mask 190a removal process. Furthermore, the range of selectable methods for removing the resist mask 190a can be broadened.

[0286] Next, as shown in Figure 8C, the sacrificial layer 119a is used as a mask (also called a hard mask) to remove a portion of the first sacrificial layer 118A and form the sacrificial layer 118a.

[0287] The first sacrificial layer 118A and the second sacrificial layer 119A can be processed by wet etching or dry etching, respectively. It is preferable to process the first sacrificial layer 118A and the second sacrificial layer 119A by anisotropic etching.

[0288] By using the wet etching method, the damage to the first layer 113A during processing of the first sacrificial layer 118A and the second sacrificial layer 119A can be reduced compared to using the dry etching method. When using the wet etching method, it is preferable to use, for example, a developer, an aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed solution containing two or more of these.

[0289] Furthermore, when using the dry etching method, the degradation of the first layer 113A can be suppressed by not using an oxygen-containing gas as the etching gas. When using the dry etching method, it is preferable to use a gas containing noble gases (also called rare gases) such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He as the etching gas.

[0290] For example, when an aluminum oxide film formed using the ALD method is used as the first sacrificial layer 118A, the first sacrificial layer 118A can be processed by dry etching using CHF3 and He. Also, when an In-Ga-Zn oxide film formed using the sputtering method is used as the second sacrificial layer 119A, the second sacrificial layer 119A can be processed by wet etching using diluted phosphoric acid. Alternatively, it may be processed by dry etching using CH4 and Ar. Alternatively, the second sacrificial layer 119A can be processed by wet etching using diluted phosphoric acid. Furthermore, when a tungsten film formed using the sputtering method is used as the second sacrificial layer 119A, the second sacrificial layer 119A can be processed by dry etching using CF4 and O2, or CF4, Cl2, and O2.

[0291] Next, as shown in Figure 8C, the sacrificial layers 119a and 118a are used as a hard mask to remove a portion of the first layer 113A and form the first layer 113a.

[0292] As a result, as shown in Figure 8C, in the region corresponding to the sub-pixel 110a, the stacked structure of the first layer 113a, the sacrificial layer 118a, and the sacrificial layer 119a remains on the conductive layer 129a. In addition, in the region corresponding to the connection portion 140, the stacked structure of the sacrificial layer 118a and the sacrificial layer 119a remains on the conductive layer 123.

[0293] The edge of the first layer 113a is located outside the edge of the conductive layer 129a. This configuration allows for a higher aperture ratio of the pixels.

[0294] Furthermore, by having the first layer 113a cover the top and sides of the conductive layer 129a, subsequent processes can be carried out without exposing the conductive layers 111a, 112a, 126a, and 129a. If the edges of these conductive layers are exposed, corrosion may occur during etching processes. Products generated by the corrosion of the conductive layers may be unstable; for example, in the case of wet etching, they may dissolve in the solution, and in the case of dry etching, there is a concern that they may scatter into the atmosphere. Dissolution of the products into the solution or scattering into the atmosphere may cause the products to adhere to the processed surface and the sides of the first layer 113a, for example, adversely affecting the characteristics of the light-emitting device or potentially forming a leak path between multiple light-emitting devices. In addition, in areas where the edges of these conductive layers are exposed, the adhesion between layers in contact with each other decreases, which may make the first layer 113a or the conductive layer more prone to delamination.

[0295] By configuring the first layer 113a to cover the top and side surfaces of the conductive layer 129a, for example, the yield of the light-emitting device can be improved, and the display quality of the light-emitting device can be improved.

[0296] Through the above process, it is possible to remove the 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.

[0297] Alternatively, a portion of the first layer 113A may be removed using the resist mask 190a. After that, the resist mask 190a may be removed.

[0298] The first layer 113A is preferably processed by anisotropic etching. In particular, anisotropic dry etching is preferred. Alternatively, wet etching may be used.

[0299] When using the dry etching method, the degradation of the first layer 113A can be suppressed by not using an oxygen-containing gas as the etching gas.

[0300] Furthermore, an etching gas containing oxygen may be used. Including oxygen in the etching gas can increase the etching rate. Therefore, etching can be performed under low power conditions while maintaining a sufficiently fast etching rate. This suppresses damage to the first layer 113A. Additionally, it suppresses problems such as the adhesion of reaction products generated during etching.

[0301] When using the dry etching method, it is preferable to use an etching gas containing one or more noble gases (also called rare gases) such as H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He, Ar. Alternatively, it is preferable to use an etching gas containing one or more of these and oxygen. Or, oxygen gas may be used as the etching gas. Specifically, for example, a gas containing H2 and Ar, or a gas containing CF4 and He, can be used as the etching gas. Also, for example, a gas containing CF4, He, and oxygen can be used as the etching gas.

[0302] Next, as shown in Figure 9A, a second layer 113B is formed on the sacrificial layer 119a, the conductive layer 129b, and the conductive layer 129c, 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.

[0303] As shown in Figure 9A, in the cross-sectional view between Y1 and Y2, the end of the second layer 113B on the connection portion 140 side is located inward (towards the display portion) than the end of the first sacrificial layer 118B.

[0304] The second layer 113B is the layer that will later become the second layer 113b. The second layer 113b emits light of a different color than the first layer 113a. The configuration and materials applicable to the second layer 113b are the same as those for the first layer 113a. The second layer 113B can be deposited using the same method as the first layer 113A.

[0305] The first sacrificial layer 118B can be formed using a material applicable to the first sacrificial layer 118A. The second sacrificial layer 119B can be formed using a material applicable to the second sacrificial layer 119A.

[0306] Next, as shown in Figure 9A, a resist mask 190b is formed on the second sacrificial layer 119B.

[0307] The resist mask 190b is positioned in a location that overlaps with the area that will later become the subpixel 110b. As shown in Figure 7B, it is preferable that the resist mask 190b has one island-shaped pattern for each subpixel 110b. Alternatively, as shown in Figure 7E, the resist mask 190b may have one strip-shaped pattern for multiple subpixels 110b arranged in a row.

[0308] In this case, it is preferable to form the resist mask 190b such that its edge is located outside the edge of the conductive layer 129b. This allows the edge of the second layer 113b, which will be formed later, to be located outside the edge of the conductive layer 129b.

[0309] The resist mask 190b may also be provided in a position that overlaps with the area that will later become the connection portion 140.

[0310] Next, as shown in Figure 9B, a portion of the second sacrificial layer 119B is removed using the resist mask 190b to form a new sacrificial layer 119b. The sacrificial layer 119b remains in the region that will later become the subpixel 110b.

[0311] Subsequently, the resist mask 190b is removed. Then, using the sacrificial layer 119b as a hard mask, a portion of the first sacrificial layer 118B is removed to form the sacrificial layer 118b.

[0312] Then, as shown in Figure 9C, the sacrificial layers 119b and 118b are used as a hard mask to remove a portion of the second layer 113B and form the second layer 113b.

[0313] As a result, as shown in Figure 9C, in the region corresponding to the sub-pixel 110b, the stacked structure of the second layer 113b, the sacrificial layer 118b, and the sacrificial layer 119b remains on the conductive layer 129b. In addition, in the region corresponding to the connection portion 140, the stacked structure of the sacrificial layer 118a and the sacrificial layer 119a remains on the conductive layer 123.

[0314] The edge of the second layer 113b is located outside the edge of the conductive layer 129b. This configuration allows for an increase in the aperture ratio of the pixels.

[0315] Furthermore, since the second layer 113b covers the top and sides of the conductive layer 129b, subsequent processes can be carried out without exposing the conductive layers 111b, 112b, 126b, and 129b. Therefore, the yield of the light-emitting device can be improved, and the display quality of the light-emitting device can be improved.

[0316] By following the above steps, the areas 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. The same methods applicable to the processing of the first layer 113A, the first sacrificial layer 118A, and the second sacrificial layer 119A can be used to process these layers.

[0317] Next, as shown in Figure 10A, a third layer 113C is formed on the sacrificial layer 119a, the sacrificial layer 119b, and the conductive layer 129c, 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.

[0318] As shown in Figure 10A, in the cross-sectional view between Y1 and Y2, the end of the third layer 113C on the connection portion 140 side is located inward (towards the display portion) than the end of the first sacrificial layer 118C.

[0319] The third layer 113C is the layer that will later become the third layer 113c. The third layer 113c emits light of a different color than the first layer 113a and the second layer 113b. The configuration and materials applicable to the third layer 113c are the same as those for the first layer 113a. The third layer 113C can be deposited using the same method as the first layer 113A.

[0320] The first sacrificial layer 118C can be formed using a material applicable to the first sacrificial layer 118A. The second sacrificial layer 119C can be formed using a material applicable to the second sacrificial layer 119A.

[0321] Next, as shown in Figure 10A, a resist mask 190c is formed on the second sacrificial layer 119C.

[0322] The resist mask 190c is positioned in a location that overlaps with the area that will later become the subpixel 110c. As shown in Figure 7C, it is preferable that the resist mask 190c has one island-shaped pattern for each subpixel 110c. Alternatively, as shown in Figure 7F, the resist mask 190c may have one strip-shaped pattern for multiple subpixels 110c arranged in a row.

[0323] In this case, it is preferable to form the resist mask 190c such that its edge is located outside the edge of the conductive layer 129c. This allows the edge of the third layer 113c, which will be formed later, to be located outside the edge of the conductive layer 129c.

[0324] The resist mask 190c may also be provided in a position that overlaps with the area that will later become the connection portion 140.

[0325] Next, as shown in Figure 10B, a portion of the second sacrificial layer 119C is removed using the resist mask 190c to form a new sacrificial layer 119c. The sacrificial layer 119c remains in the region that will later become the subpixel 110c.

[0326] Subsequently, the resist mask 190c is removed. Then, using the sacrificial layer 119c as a hard mask, a portion of the first sacrificial layer 118C is removed to form the sacrificial layer 118c.

[0327] Then, as shown in Figure 10C, the sacrificial layers 119c and 118c are used as a hard mask to remove a portion of the third layer 113C and form the third layer 113c.

[0328] As a result, as shown in Figure 10C, in the region corresponding to the sub-pixel 110c, the stacked structure of the third layer 113c, the sacrificial layer 118c, and the sacrificial layer 119c remains on the conductive layer 129c. In addition, in the region corresponding to the connection portion 140, the stacked structure of the sacrificial layer 118a and the sacrificial layer 119a remains on the conductive layer 123.

[0329] The edge of the third layer 113c is located outside the edge of the conductive layer 129c. This configuration allows for an increase in the aperture ratio of the pixels.

[0330] Furthermore, since the third layer 113c covers the top and sides of the conductive layer 129c, subsequent processes can be carried out without exposing the conductive layers 111c, 112c, 126c, and 129c. Therefore, the yield of the light-emitting device can be improved, and the display quality of the light-emitting device can be improved.

[0331] By following the above steps, the areas of the third layer 113C, the first sacrificial layer 118C, and the second sacrificial layer 119C that do not overlap with the resist mask 190c can be removed. The same methods applicable to the processing of the first layer 113A, the first sacrificial layer 118A, and the second sacrificial layer 119A can be used to process these layers.

[0332] Furthermore, it is preferable that the sides of the first layer 113a, the second layer 113b, and the third layer 113c are perpendicular or approximately perpendicular to the surface to be formed. For example, it is preferable that the angle between the surface to be formed and these sides be 60 degrees or more and 90 degrees or less.

[0333] Next, as shown in Figure 11A, the sacrificial layers 119a, 119b, and 119c are removed. As a result, sacrificial layer 118a is exposed on conductive layer 111a, sacrificial layer 118b is exposed on conductive layer 111b, sacrificial layer 118c is exposed on conductive layer 111c, and sacrificial layer 118a is exposed on conductive layer 123.

[0334] As described later in example 2 of the manufacturing method, the process may proceed to the formation of the insulating film 125A without removing the sacrificial layers 119a, 119b, and 119c.

[0335] The same method as the sacrificial layer processing method can be used for the sacrificial layer removal process. In particular, by using a wet etching method, the damage inflicted on the first layer 113a, the second layer 113b, and the third layer 113c when removing the sacrificial layer can be reduced compared to when using a dry etching method.

[0336] Alternatively, the sacrificial layer may be removed by dissolving it in a solvent such as water or alcohol. Examples of alcohols include ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0337] 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 to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 120°C. A reduced pressure atmosphere is preferable because it allows drying at a lower temperature.

[0338] Next, as shown in Figure 11B, an insulating film 125A is formed to cover the first layer 113a, the second layer 113b, the third layer 113c, and the sacrificial layers 118a, 118b, and 118c.

[0339] For the insulating film 125A, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, magnesium oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxidative nitride insulating films include silicon oxidative nitride films and aluminum oxidative nitride films. Examples of nitride oxide insulating films include silicon nitride film and aluminum nitride film. In addition, metal oxide films such as indium gallium zinc oxide films may be used.

[0340] Furthermore, it is preferable that the insulating film 125A functions as a barrier insulating film against at least one of water and oxygen. Alternatively, it is preferable that the insulating film 125A has a function to suppress the diffusion of at least one of water and oxygen. Alternatively, it is preferable that the insulating film 125A has a function to capture or fix (also called gettering) at least one of water and oxygen.

[0341] In this specification, a barrier insulating film refers to an insulating film that has barrier properties. In this specification, barrier properties refer to the function of suppressing the diffusion of the corresponding substance (also called low permeability), or the function of capturing or fixing the corresponding substance (also called gettering).

[0342] The insulating film 125A has the function of a barrier insulating film or a gettering function as described above, thereby suppressing the intrusion of impurities (typically water or oxygen) that could diffuse from the outside into each light-emitting device. This configuration makes it possible to provide a display device with excellent reliability.

[0343] Next, as shown in Figure 11C, an insulating layer 127 is formed on the insulating film 125A.

[0344] Organic materials can be used for the insulating layer 127. Examples of organic materials include acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. Alternatively, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin may be used for the insulating layer 127. A photosensitive resin can also be used for the insulating layer 127. Photoresist may be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0345] The insulating layer 127 can be patterned by, for example, applying a photosensitive resin and then exposing and developing it.

[0346] Etching may be performed to adjust the surface height of the insulating layer 127. The insulating layer 127 may also be processed, for example, by ashing using oxygen plasma.

[0347] There are no particular limitations on the method for forming the insulating layer 127. For example, it can be formed using wet film formation methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating. In particular, it is preferable to form the insulating layer 127 by spin coating.

[0348] The insulating film 125A and the insulating layer 127 are preferably formed using a method that minimizes 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 preferable that it be formed using a method that minimizes damage to the EL layer more 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 even more preferably 80°C or lower). For example, an aluminum oxide film can be formed as the insulating film 125A using the ALD method. The ALD method is preferable because it can minimize film formation damage and allow for the formation of a film with high coverage.

[0349] Next, as shown in Figure 12A, at least a portion of the insulating film 125A and the sacrificial layers 118a, 118b, and 118c are removed to expose the first layer 113a, the second layer 113b, and the third layer 113c.

[0350] 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 insulating film for both the sacrificial layers 118a, 118b, and 118c and the insulating film 125A using the ALD method, and it is more preferable to form an aluminum oxide film using the ALD method.

[0351] As shown in Figure 12A, the portion of the insulating film 125A that overlaps with the insulating layer 127 remains as the insulating layer 125. Similarly, the sacrificial layers 118a, 118b, and 118c also retain portions that overlap with the insulating layer 127.

[0352] Thus, one embodiment of the present invention allows for a display device in which the sacrificial layer remains. Depending on the shape of the insulating layer 127, the sacrificial layers 118a, 118b, and 118c may all be removed. Therefore, the sacrificial layers 118a, 118b, and 118c do not need to remain in the display device.

[0353] The insulating layer 125 (and further insulating layer 127) is provided so as to cover the sides of the first layer 113a, the second layer 113b, and the third layer 113c. This prevents the film formed later from coming into contact with the sides of these layers, thereby preventing the light-emitting device from short-circuiting. Furthermore, it is possible to suppress damage to the first layer 113a, the second layer 113b, and the third layer 113c in subsequent processes.

[0354] The same method as the sacrificial layer processing method can be used for the sacrificial layer removal process. Furthermore, the same method as the method used for the removal of sacrificial layers 119a, 119b, and 119c can be used for the removal of sacrificial layers 118a, 118b, and 118c.

[0355] The insulating film 125A is preferably processed by a dry etching method. 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 the sacrificial layer.

[0356] Next, as shown in Figure 12B, a fourth layer 114 is formed so as to cover the insulating layer 125, insulating layer 127, the first layer 113a, the second layer 113b, and the third layer 113c.

[0357] Figure 12B shows a cross-sectional view between Y1 and Y2, illustrating an example where a fourth layer 114 is provided at the connection portion 140. Depending on the conductivity of the fourth layer 114, the fourth layer 114 may be provided at the connection portion 140.

[0358] Alternatively, as shown in Figure 12C, it is preferable that the end of the fourth layer 114 on the connection portion 140 side is located inside (towards the display portion) of the connection portion 140. For example, it is preferable to use a mask to define the film deposition area when depositing the fourth layer 114.

[0359] The materials that can be used as the fourth layer 114 are as described above. The fourth layer 114 can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating. The fourth layer 114 may also be formed using a premixed material.

[0360] The fourth layer 114 is provided so as to cover the upper surfaces of the first layer 113a, the second layer 113b, and the third layer 113c, as well as the upper and side surfaces of the insulating layer 127. If the fourth layer 114 has high conductivity, there is a risk of the light-emitting device short-circuiting if the fourth layer 114 comes into contact with any side surface of the first layer 113a, the second layer 113b, or the third layer 113c. However, in a display device according to one embodiment of the present invention, the insulating layers 125 and 127 cover the side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c, thereby suppressing contact between the highly conductive fourth layer 114 and these layers, and thus preventing the light-emitting device from short-circuiting. This improves the reliability of the light-emitting device.

[0361] Furthermore, since the spaces between the first layer 113a and the second layer 113b, and between the second layer 113b and the third layer 113c are filled with insulating layers 125 and 127, the surface of the fourth layer 114 is flatter and has fewer steps than when the insulating layers 125 and 127 are not provided. This improves the coverage of the fourth layer 114.

[0362] Then, as shown in Figure 12B or Figure 12C, a common electrode 115 is formed on the fourth layer 114 (and on the conductive layer 123).

[0363] In Figure 12B, the conductive layer 123 and the common electrode 115 are electrically connected via the fourth layer 114. In Figure 12C, the conductive layer 123 and the common electrode 115 are electrically connected by direct contact.

[0364] When depositing the common electrode 115, a mask may be used to define the deposition area. Alternatively, the common electrode 115 may be processed after deposition using a resist mask or the like, without using such a mask during deposition.

[0365] The materials that can be used as the common electrode 115 are as described above. For the formation of the common electrode 115, for example, sputtering or vacuum deposition can be used. Alternatively, a film formed by deposition and a film formed by sputtering may be laminated together.

[0366] Subsequently, a protective layer 131 is formed on the common electrode 115. Furthermore, by using a resin layer 122 to bond the substrate 120 onto the protective layer 131, the display device 100 shown in Figure 1B can be manufactured.

[0367] The materials and film formation methods that can be used for the protective layer 131 are as described above. Examples of film formation methods for the protective layer 131 include vacuum deposition, sputtering, CVD, and ALD. The protective layer 131 may be a single layer or a multilayer structure.

[0368] The shape of the insulating layer 127 is not particularly limited. Figures 13A to 13C and 14A show modified examples of the cross-sectional view shown in Figure 12B. Specifically, these modified examples differ in the shape of the insulating layer 127.

[0369] As shown in Figure 12B, the upper surface of the insulating layer 127 can be configured to have a shape in which the center and its vicinity are recessed in a cross-sectional view, that is, a shape having a concave curved surface.

[0370] Furthermore, as shown in Figure 13A, the upper surface of the insulating layer 127 can be configured to have a shape that bulges in the center and its vicinity when viewed in cross-section, that is, a shape with a convex curved surface.

[0371] Furthermore, as shown in Figure 13B, the upper surface of the insulating layer 127 may have a flat portion in cross-sectional view.

[0372] Figures 12B and 13A show an example where the height of the upper surfaces of the insulating layers 125 and 127 is lower than the height of the upper surfaces of the first layer 113a, the second layer 113b, and the third layer 113c. Alternatively, the height of the upper surface of the insulating layer 127 may be higher than the height of the upper surfaces of the first layer 113a, the second layer 113b, and the third layer 113c.

[0373] As shown in Figure 13B, the height of at least one of the upper surfaces of the first layer 113a, the second layer 113b, and the third layer 113c may match or approximately match the height of the upper surface 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.

[0374] Furthermore, as shown in Figure 13C, the height of at least one of the upper surfaces of the first layer 113a, the second layer 113b, and the third layer 113c is equal to or approximately equal to the height of the upper surface of the insulating layer 125, and the upper surface of the insulating layer 127 may have a concave curved surface. Alternatively, the upper surface of the insulating layer 127 may have a convex curved surface.

[0375] Furthermore, the upper surface of the insulating layer 127 may have one or both of a convex curved surface and a concave curved surface. Also, the number of convex curved surfaces and concave curved surfaces on the upper surface of the insulating layer 127 is not limited and can be one or more.

[0376] 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 they 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.

[0377] As shown in Figure 14A, the heights of the upper surfaces of the first layer 113a, the second layer 113b, and the third layer 113c may be different. The height of the upper surface of the insulating layer 125 is the same as or approximately the same as the height of the upper surface of the first layer 113a on the first layer 113a side, and the height is the same as or approximately the same as the height of the upper surface of the second layer 113b on the second layer 113b side. The upper 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. Thus, it is preferable that the heights of the insulating layer 125 and insulating layer 127 are the same as the heights of the upper surfaces of adjacent EL layers. Alternatively, the upper surface may have a flat portion, with the height being the same as the height of the upper surface of any of the adjacent EL layers.

[0378] Furthermore, as shown in Figure 14B, the insulating layer 125 does not need to be provided. In this case, it is preferable to use an organic material for the insulating layer 127 that causes less damage to the first layer 113a, the second layer 113b, and the third layer 113c. For example, it is preferable to use an organic material for the insulating layer 127 such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin.

[0379] Furthermore, as shown in Figure 14C, the fourth layer 114 may be omitted, and the common electrode 115 may be formed to cover the insulating layer 127, the first layer 113a, the second layer 113b, and the third layer 113c. In other words, in light-emitting devices that emit light of different colors, all the layers constituting the EL layer may be manufactured separately. In this case, the EL layer of each light-emitting device is formed in an island-like manner.

[0380] In this case, there is a risk of the light-emitting device short-circuiting if the common electrode 115 comes into contact with any side surface of the first layer 113a, the second layer 113b, or the third layer 113c. However, in a display device according to one aspect of the present invention, the insulating layer 125 and the insulating layer 127 cover the sides of the first layer 113a, the second layer 113b, and the third layer 113c, thereby suppressing contact between the common electrode 115 and these layers and preventing a short circuit in the light-emitting device. This improves the reliability of the light-emitting device.

[0381] Furthermore, since the spaces between the first layer 113a and the second layer 113b, and between the second layer 113b and the third layer 113c are filled with insulating layers 125 and 127, the surface of the common electrode 115 is flatter and has fewer steps than when the insulating layers 125 and 127 are not provided. This improves the coverage of the common electrode 115.

[0382] [Example of a method for manufacturing a display device 2] Next, an example of a method for manufacturing a display device will be explained using Figures 15 and 16. Figures 15A to 15C and Figure 16 show side by side the cross-sectional view between the dashed-dotted line X1-X2 and the cross-sectional view between Y1-Y2 in Figure 1A.

[0383] In this manufacturing method example 2, the steps shown in Figures 15 and 16 are performed after the steps shown in Figure 10C. Note that detailed explanations may be omitted for parts that are the same as those in this manufacturing method example 1.

[0384] In this fabrication method example 2, the insulating film 125A is formed on the sacrificial layers 119a, 119b, and 119c without removing them (see Figure 15A).

[0385] Next, as shown in Figure 15B, an insulating layer 127 is formed on the insulating film 125A.

[0386] Next, as shown in Figure 15C, at least a portion of the insulating film 125A, sacrificial layers 119a, 119b, 119c, and sacrificial layers 118a, 118b, 118c is removed to expose the first layer 113a, the second layer 113b, and the third layer 113c.

[0387] Sacrificial layers 119a, 119b, 119c and sacrificial layers 118a, 118b, 118c may be removed in separate processes or in the same process. Similarly, sacrificial layers 118a, 118b, 118c and insulating film 125A may be removed in separate processes or in the same process. Furthermore, sacrificial layers 119a, 119b, 119c, sacrificial layers 118a, 118b, 118c, and insulating film 125A may be removed all at once.

[0388] As shown in Figure 15C, the portion of the insulating film 125A that overlaps with the insulating layer 127 remains as the insulating layer 125. Similarly, the sacrificial layers 119a, 119b, 119c and sacrificial layers 118a, 118b, 118c also retain portions that overlap with the insulating layer 127.

[0389] Thus, in one aspect of the present invention, the display device may have a configuration in which not only the first sacrificial layer but also the second sacrificial layer remains.

[0390] Subsequently, as shown in Figure 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.

[0391] [Example 3 of a method for manufacturing a display device] Next, an example of a method for manufacturing a display device will be explained using Figure 17. Figures 17A and 17B show side by side the cross-sectional view between the dashed lines X1 and X2 in Figure 1A, and the cross-sectional view between Y1 and Y2.

[0392] This third example of the fabrication method describes a fabrication method for forming an EL layer with the same configuration in all subpixels.

[0393] For example, when creating a full-color display device 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 is sometimes possible to apply the same EL layer configuration to all subpixels.

[0394] First, similar to manufacturing method example 1, conductive layers 111a, 111b, 111c to conductive layers 129a, 129b, 129c are formed sequentially on the transistor-containing layer 101. Then, as shown in Figure 17A, an EL layer 113 is formed on conductive layers 129a, 129b, 129c, and 123, a first sacrificial layer 118A is formed on the EL layer 113, and a second sacrificial layer 119A is formed on the first sacrificial layer 118A.

[0395] Then, as shown in Figure 17A, a resist mask 190 is formed on the second sacrificial layer 119A. The resist mask 190 is placed in a position that overlaps with the regions that will later become subpixels 110a, 110b, and 110c.

[0396] In this case, it is preferable to form the resist mask 190 such that its edges are located outside the edges of the conductive layers 129a, 129b, and 129c. This allows the edges of the first layer 113a, which will be formed later, to be located outside the edges of the conductive layer 129a. Similarly, the edges of the second layer 113b, which will be formed later, can be located outside the edges of the conductive layer 129b, and the edges of the third layer 113c, which will be formed later, can be located outside the edges of the conductive layer 129c.

[0397] Furthermore, it is preferable to also provide the resist mask 190 in a position that overlaps with the connection portion 140. This helps to suppress damage to the conductive layer 123 during the manufacturing process of the display device.

[0398] Then, similar 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, a portion of the EL layer 113 is removed using the sacrificial layers 119a and 118a as masks. As a result, the first layer 113a, the second layer 113b, and the third layer 113c can be formed, as shown in Figure 17B. Since the first layer 113a, the second layer 113b, and the third layer 113c are layers formed by processing the EL layer 113, they have the same structure as each other.

[0399] In manufacturing method example 1, the first layer 113a, the second layer 113b, and the third layer 113c are formed from different films, requiring three processing steps for the EL layer 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 performing the EL layer processing using a resist mask only once. This reduces the number of manufacturing steps, which is preferable.

[0400] After the process shown in Figure 17B, the process can proceed to the process shown in Figure 11A or Figure 15A. Therefore, for explanations of subsequent steps, please refer to Manufacturing Method Examples 1 and 2.

[0401] As described above, in the manufacturing method of the display device of this embodiment, the island-shaped EL layer is formed not using a fine metal mask, but by processing after the EL layer has been deposited on one surface. Therefore, the island-shaped EL layer can be formed with a uniform thickness. This makes it possible to realize a high-definition display device or a display device with a high aperture ratio.

[0402] The first, second, and third layers constituting each color of light-emitting device are formed in separate processes. Therefore, each EL layer can be fabricated with a configuration (material, film thickness, etc.) suitable for each color of light-emitting device. This makes it possible to produce light-emitting devices with excellent characteristics.

[0403] A display device according to one aspect of the present invention has an insulating layer covering the sides of the light-emitting layer and the carrier transport layer. In the manufacturing process of the display device, the EL layer is processed with the light-emitting layer and the carrier transport layer stacked together, so the display device has a configuration that reduces damage to the light-emitting layer. Furthermore, the insulating layer prevents contact between the island-shaped EL layer and the carrier injection layer or common electrode, thereby preventing short circuits in the light-emitting device.

[0404] Furthermore, in one embodiment of the present invention, the display device is configured such that the light-emitting layer covers the upper and side surfaces of the pixel electrodes. With this configuration, the aperture ratio can be increased compared to a configuration in which the edges of the light-emitting layer are located inward from the edges of the pixel electrodes.

[0405] This embodiment can be combined with other embodiments as appropriate. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, these configuration examples can be combined as appropriate.

[0406] (Embodiment 2) In this embodiment, an example of the configuration of a light-emitting device that can be applied to a display device according to one aspect of the present invention will be described with reference to Figures 18 to 22.

[0407] The display device 500 shown in Figures 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.

[0408] The light-emitting device 550R shown in Figures 18A and 18B has a light-emitting unit 512R_1 between a pair of electrodes (electrode 501, electrode 502). Similarly, the light-emitting device 550G has a light-emitting unit 512G_1, and the light-emitting device 550B has a light-emitting unit 512B_1.

[0409] In other words, the light-emitting devices 550R, 550G, and 550B shown in Figures 18A and 18B are each single-structure light-emitting devices having one light-emitting unit.

[0410] The light-emitting device 550R shown in Figure 18C has a configuration in which two light-emitting units (light-emitting unit 512R_1, light-emitting unit 512R_2) are stacked between a pair of electrodes (electrode 501, electrode 502) via a charge generation layer 531. Similarly, the light-emitting device 550G has light-emitting unit 512G_1, light-emitting unit 512G_2, and the light-emitting device 550B has light-emitting unit 512B_1, light-emitting unit 512B_2.

[0411] In other words, the light-emitting devices 550R, 550G, and 550B shown in Figure 18C are each tandem-structured light-emitting devices having two light-emitting units.

[0412] In this specification, a configuration in which multiple light-emitting units are connected in series via a charge generation layer 531, as shown in light-emitting devices 550R, 550G, and 550B in Figure 18C, is called a tandem structure. On the other hand, a configuration in which one light-emitting unit is located between a pair of electrodes, as shown in light-emitting devices 550R, 550G, and 550B in Figures 18A and 18B, is called a single structure. In this specification, the term "tandem structure" is used, but it is not limited to this, and for example, a tandem structure may also be called a stacked structure. By using a tandem structure, it is possible to create a light-emitting device that can emit light with high brightness. Furthermore, compared to a single structure, a tandem structure can reduce the current required to obtain the same brightness, thus improving reliability.

[0413] Furthermore, a structure in which the light-emitting layer is made separately for each light-emitting device, as shown in the display device 500 in Figures 18A to 18C, is sometimes called an SBS (Side By Side) structure.

[0414] The display device 500 shown in Figure 18C has a tandem structure for its light-emitting devices and can be said to have an SBS structure. Therefore, it can combine the advantages of both a tandem structure and an SBS structure. The display device 500 shown in Figure 18C has a structure in which two light-emitting units are formed in series, so it may also be called a two-stage tandem structure. In the two-stage tandem structure of the light-emitting device 550R shown in Figure 18C, a second light-emitting unit having a red light-emitting layer is stacked on top of a first light-emitting unit having a red light-emitting layer. Similarly, in the two-stage tandem structure of the light-emitting device 550G shown in Figure 18C, a second light-emitting unit having a green light-emitting layer is stacked on top of a first light-emitting unit having a green light-emitting layer, and in the two-stage tandem structure of the light-emitting device 550B, a second light-emitting unit having a blue light-emitting layer is stacked on top of a first light-emitting unit having a blue light-emitting layer.

[0415] Electrode 501 functions as a pixel electrode and is provided for each light-emitting device. Electrode 502 functions as a common electrode and is provided in common to multiple light-emitting devices.

[0416] The light-emitting unit has at least one light-emitting layer. The number of light-emitting layers in the light-emitting unit is not limited to one, two, three, or four or more layers.

[0417] The light-emitting unit 512R_1 has layers 521, 522, light-emitting layer 523R, layer 524, etc. Figure 18A shows an example in which the light-emitting unit 512R_1 has layer 525, and Figure 18B shows an example in which the light-emitting unit 512R_1 does not have layer 525, and layer 525 is provided in common among the light-emitting devices. In this case, layer 525 can be called a common layer. By providing one or more common layers to multiple light-emitting devices in this way, the manufacturing process can be simplified, and thus manufacturing costs can be reduced.

[0418] The light-emitting unit 512R_2 includes layers 522, luminescent layer 523R, layer 524, etc. While Figure 18C shows an example where layer 525 is provided as a common layer, layer 525 may be provided for each light-emitting device. In other words, layer 525 may be included in the light-emitting unit 512R_2.

[0419] Layer 521 includes, for example, a layer containing a material with high hole injection capabilities (hole injection layer). Layer 522 includes, for example, a layer containing a material with high hole transport capabilities (hole transport layer). Layer 524 includes, for example, a layer containing a material with high electron transport capabilities (electron transport layer). Layer 525 includes, for example, a layer containing a material with high electron injection capabilities (electron injection layer).

[0420] Alternatively, the configuration may include layer 521 having an electron injection layer, layer 522 having an electron transport layer, layer 524 having a hole transport layer, and layer 525 having a hole injection layer.

[0421] Note that layer 522, light-emitting layer 523R, and layer 524 may have the same configuration (material, film thickness, etc.) in light-emitting unit 512R_1 and light-emitting unit 512R_2, or they may have different configurations.

[0422] In Figure 18A, etc., layers 521 and 522 are shown separately, but the diagram is not limited to this. For example, if layer 521 has the functions of both a hole injection layer and a hole transport layer, or if layer 521 has the functions of both an electron injection layer and an electron transport layer, layer 522 may be omitted.

[0423] Furthermore, the charge generation layer 531 has the function of injecting electrons into one of the light-emitting units 512R_1 and 512R_2 and holes into the other when a voltage is applied between the electrode 501 and the electrode 502.

[0424] The light-emitting layer 523R of the light-emitting device 550R contains a light-emitting material that emits red light, the light-emitting layer 523G of the light-emitting device 550G contains a light-emitting material that emits green light, and the light-emitting layer 523B of the light-emitting device 550B contains a light-emitting material that emits blue light. The light-emitting devices 550G and 550B have a configuration in which the light-emitting layer 523R of the light-emitting device 550R is replaced with the light-emitting layer 523G and the light-emitting layer 523B, respectively, and the other configurations are the same as those of the light-emitting device 550R.

[0425] Note that layers 521, 522, 524, and 525 may have the same configuration (material, film thickness, etc.) for each color of light-emitting device, or they may have different configurations.

[0426] In Figures 18A and 18B, the light-emitting units 512R_1, 512G_1, and 512B_1 can be formed as island-like layers. In other words, the EL layer 113 shown in Figures 18A and 18B corresponds to the first layer 113a, the second layer 113b, or the third layer 113c shown in Figure 1B, etc.

[0427] In Figure 18C, the light-emitting unit 512R_1, the charge generation layer 531, and the light-emitting unit 512R_2 can be formed as island-like layers. Similarly, the light-emitting unit 512G_1, the charge generation layer 531, and the light-emitting unit 512G_2 can be formed as island-like layers. The light-emitting unit 512B_1, the charge generation layer 531, and the light-emitting unit 512B_2 can also be formed as island-like layers. In other words, the EL layer 113 shown in Figure 18C corresponds to the first layer 113a, the second layer 113b, or the third layer 113c shown in Figure 1B, etc.

[0428] In Figures 18B and 18C, layer 525 corresponds to the fourth layer 114 shown in Figure 1B.

[0429] In addition, the light-emitting material of the light-emitting layer in the display device 500 is not particularly limited. For example, in the display device 500 shown in Figure 18C, the light-emitting layer 523R of the light-emitting unit 512R_1 has a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 has a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 has a fluorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 has a fluorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 has a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 has a fluorescent material.

[0430] Alternatively, in the display device 500 shown in Figure 18C, the light-emitting layer 523R of the light-emitting unit 512R_1 has a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 has a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 has a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 has a phosphorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 has a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 has a fluorescent material.

[0431] Furthermore, in one embodiment of the present invention, the display device may be configured such that all light-emitting layers are made of fluorescent material, or so that all light-emitting layers are made of phosphorescent material.

[0432] Alternatively, in the display device 500 shown in Figure 18C, the light-emitting layer 523R of light-emitting unit 512R_1 may be made of a phosphorescent material and the light-emitting layer 523R of light-emitting unit 512R_2 may be made of a fluorescent material, or the light-emitting layer 523R of light-emitting unit 512R_1 may be made of a fluorescent material and the light-emitting layer 523R of light-emitting unit 512R_2 may be made of a phosphorescent material, that is, the light-emitting materials of the first stage light-emitting layer and the second stage light-emitting layer may be made of different materials. Although the description here specifies light-emitting units 512R_1 and 512R_2, the same configuration can be applied to light-emitting units 512G_1 and 512G_2, and light-emitting units 512B_1 and 512B_2.

[0433] The display device 500 shown in Figures 19A and 19B has a plurality of light-emitting devices 550W that emit white light. On each light-emitting device 550W, 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. Here, it is preferable that the colored layers 545R, 545G, and 545B are provided on the light-emitting device 550W via a protective layer 540.

[0434] The light-emitting device 550W shown in Figure 19A has a light-emitting unit 512W between a pair of electrodes (electrode 501, electrode 502).

[0435] In other words, the 550W light-emitting device shown in Figure 19A is a single-structure light-emitting device having one light-emitting unit.

[0436] The light-emitting unit 512W includes layers 521, 522, light-emitting layer 523Q_1, light-emitting layer 523Q_2, light-emitting layer 523Q_3, layer 524, etc. The light-emitting device 550W also has layers 525, etc., between the light-emitting unit 512W and the electrode 502. Note that layer 525 can also be considered as part of the light-emitting unit 512W.

[0437] In the light-emitting device 550W shown in Figure 19A, 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 their light emission is in a complementary color relationship. Here, an example is shown in which the light-emitting unit 512W has three light-emitting layers, but the number of light-emitting layers is not limited; for example, it may have two layers.

[0438] Furthermore, the light-emitting device 550W shown in Figure 19A has a configuration in which the light-emitting layer 523R of the light-emitting device 550R shown in Figure 18B is replaced with light-emitting layers 523Q_1 to 523Q_3, while the other configurations are the same as those of the light-emitting device 550R.

[0439] The light-emitting device 550W shown in Figure 19B has a configuration in which two light-emitting units (light-emitting unit 512Q_1, light-emitting unit 512Q_2) are stacked between a pair of electrodes (electrode 501, electrode 502) via a charge generation layer 531.

[0440] The light-emitting unit 512Q_1 has layers 521, 522, light-emitting layer 523Q_1, layer 524, etc. The light-emitting unit 512Q_2 has layers 522, light-emitting layer 523Q_2, layer 524, etc. The light-emitting device 550W has layers 525, etc. between the light-emitting unit 512Q_2 and the electrode 502. Note that layer 525 can also be considered as part of the light-emitting unit 512Q_2.

[0441] In the light-emitting device 550W shown in Figure 19B, white light can be obtained from the light-emitting device 550W by selecting light-emitting layers 523Q_1 and 523Q_2 such that their light emission is complementary in color. Here, we show an example where light-emitting units 512Q_1 and 512Q_2 each have one light-emitting layer, but the number of light-emitting layers in each light-emitting unit is not limited. For example, 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.

[0442] Furthermore, the light-emitting device 550W shown in Figure 19B has a configuration in which the light-emitting layer 523R of the light-emitting device 550R shown in Figure 18C is replaced with a light-emitting layer 523Q_1, etc., and the other configurations are the same as those of the light-emitting device 550R.

[0443] The display device 500 shown in Figures 20 to 22 includes a light-emitting device 550R that emits red light, a light-emitting device 550G that emits green light, a light-emitting device 550B that emits blue light, and a light-emitting device 550W that emits white light.

[0444] The display devices shown in Figures 20A and 20B are examples that include a white light-emitting device 550W 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 that includes a white light-emitting device 550W in addition to the light-emitting devices 550R, 550G, and 550B shown in Figure 18C.

[0445] 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, light-emitting unit 512Q_2) are stacked between a pair of electrodes (electrode 501, electrode 502) via a charge generation layer 531.

[0446] 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) via a charge generation layer 531.

[0447] Light-emitting unit 512Q_1 has layers 521, 522, light-emitting layer 523Q_1, layer 524, etc. Light-emitting unit 512Q_2 has layers 522, light-emitting layer 523Q_2, layer 524, etc. Light-emitting unit 512Q_3 has layers 522, light-emitting layer 523Q_3, layer 524, etc.

[0448] In the light-emitting device 550W shown in Figures 20A and 21A, white light can be obtained from the light-emitting device 550W by selecting light-emitting layers such that the light emitted from light-emitting layer 523Q_1 and light-emitting layer 523Q_2 are complementary colors.

[0449] In the light-emitting device 550W shown in Figure 20B, white light emission can be obtained from the light-emitting device 550W by selecting light-emitting layers 523Q_1, 523Q_2, and 523Q_3 such that their light emission is in a complementary color relationship.

[0450] The light-emitting device 550W has a configuration in which the light-emitting layer 523R of the light-emitting device 550R is replaced with a light-emitting layer 523Q_1, etc., while the other configurations are the same as those of the light-emitting device 550R.

[0451] The display device 500 shown in Figure 21B is an example in which the light-emitting device 550R that emits red light, the light-emitting device 550G that emits green light, the light-emitting device 550B that emits blue light, and the light-emitting device 550W that emits white light are all a three-stage tandem structure in which three light-emitting units are stacked. In Figure 21B, the light-emitting device 550R has a light-emitting unit 512R_3 stacked on top of the light-emitting unit 512R_2 via a charge generation layer 531. The light-emitting unit 512R_3 has layers 522, light-emitting layer 523R, layer 524, etc. The same configuration can be applied to the light-emitting unit 512R_3 as to the light-emitting unit 512R_2. The same applies to the light-emitting unit 512G_3 of the light-emitting device 550G, the light-emitting unit 512B_3 of the light-emitting device 550B, and the light-emitting unit 512Q_3 of the light-emitting device 550W.

[0452] Figure 22A shows an example in which, in addition to the light-emitting devices 550R, 550G, and 550B shown in Figure 18A, a light-emitting device 550W that emits white light is also provided.

[0453] The light-emitting device 550W shown in Figure 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, from light-emitting unit 512Q_1 to light-emitting unit 512Q_n, and can emit white light because the light from these light-emitting units is in a complementary color relationship.

[0454] In Figure 22B, the light-emitting device 550R that emits red light, the light-emitting device 550G that emits green light, the light-emitting device 550B that emits blue light, and the light-emitting device 550W that emits white light all have a configuration in which n light-emitting units (n is an integer of 2 or more) are stacked. The light-emitting device 550R has n light-emitting units, from light-emitting unit 512R_1 to light-emitting unit 512R_n, each having a light-emitting layer that emits red light. The light-emitting device 550G has n light-emitting units, from light-emitting unit 512G_1 to light-emitting unit 512G_n, each having a light-emitting layer that emits green light. The light-emitting device 550B has n light-emitting units, from light-emitting unit 512B_1 to light-emitting unit 512B_n, each having a light-emitting layer that emits blue light.

[0455] In this way, by increasing the number of stacked light-emitting units, the brightness obtained from the light-emitting device with the same amount of current can be increased in proportion to the number of stacks. Furthermore, by increasing the number of stacked light-emitting units, the current required to obtain the same brightness can be reduced, thus reducing the power consumption of the light-emitting device in proportion to the number of stacks.

[0456] This embodiment can be combined with other embodiments as appropriate.

[0457] (Embodiment 3) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 23 to 27.

[0458] The display device of this embodiment can be a high-resolution display device or a large-screen display device. Therefore, the display device of this embodiment can be used in electronic devices with relatively large screens, such as television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal information terminals, and audio playback devices.

[0459] [Display device 100A] Figure 23 shows a perspective view of the display device 100A, and Figure 24A shows a cross-sectional view of the display device 100A.

[0460] The display device 100A has a configuration in which substrate 152 and substrate 151 are bonded together. In Figure 23, substrate 152 is clearly indicated by a dashed line.

[0461] The display device 100A includes a display unit 162, a connection unit 140, a circuit 164, wiring 165, etc. Figure 23 shows an example in which IC 173 and FPC 172 are mounted on the display device 100A. Therefore, the configuration shown in Figure 23 can also be described as a display module having the display device 100A, an IC (integrated circuit), and an FPC.

[0462] The connection portion 140 is provided on the outside of the display portion 162. The connection portion 140 can be provided along one or more sides of the display portion 162. There may be one or more connection portions 140. Figure 23 shows an example in which the connection portion 140 is provided so as to surround all four sides of the display portion. At the connection portion 140, the common electrode of the light-emitting device and the conductive layer are electrically connected, and a potential can be supplied to the common electrode.

[0463] For example, a scan line drive circuit can be used as circuit 164.

[0464] Wiring 165 has the function of supplying signals and power to the display unit 162 and the circuit 164. These signals and power are input to wiring 165 from an external source via FPC 172 or from IC 173.

[0465] Figure 23 shows an example in which IC 173 is mounted on the substrate 151 using a COG (Chip On Glass) method or COF (Chip On Film) method. IC 173 can be an IC having, for example, a scan line drive circuit or a signal line drive circuit. Note that the display device 100A and the display module may be configured without an IC. Alternatively, the IC may be mounted on an FPC using a COF method or the like.

[0466] Figure 24A shows an example of a cross-section of the display device 100A when 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 are cut.

[0467] The display device 100A shown in Figure 24A has a transistor 201, a transistor 205, a light-emitting device 130a that emits red light, a light-emitting device 130b that emits green light, and a light-emitting device 130c that emits blue light, etc., between substrates 151 and 152.

[0468] Here, if a pixel of a display device has three types of subpixels, each having a light-emitting device that emits light of different colors, examples of such three subpixels include subpixels of three colors: R, G, and B; and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). If there are four such subpixels, examples of such four subpixels include subpixels of four colors: R, G, B, and white (W); and subpixels of four colors: R, G, B, and Y.

[0469] The light-emitting devices 130a, 130b, and 130c each have a structure similar to the stacked structure shown in Figure 1B, except that the pixel electrode configuration differs. For details of the light-emitting devices, please refer to Embodiment 1.

[0470] The light-emitting device 130a has a conductive layer 111a, a conductive layer 112a on the conductive layer 111a, and a conductive layer 126a on the conductive layer 112a. All of the conductive layers 111a, 112a, and 126a can be called pixel electrodes, or only a part of them can be called pixel electrodes.

[0471] The conductive layer 111a is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The edge of the conductive layer 112a is located outside the edge of the conductive layer 111a. The edges of the conductive layer 112a and the conductive layer 126a are aligned or approximately aligned. For example, conductive layers that function as reflective electrodes can be used for conductive layers 111a and 112a, and a conductive layer that functions as a transparent electrode can be used for conductive layer 126a.

[0472] The conductive layers 111b, 112b, and 126b in the light-emitting device 130b, and the conductive layers 111c, 112c, and 126c in the light-emitting device 130c are the same as the conductive layers 111a, 112a, and 126a in the light-emitting device 130a, so a detailed explanation is omitted.

[0473] The conductive layers 111a, 111b, and 111c have recesses formed to cover the openings provided in the insulating layer 214. Layer 128 is embedded in these recesses.

[0474] Layer 128 has the function of flattening the recesses of the conductive layers 111a, 111b, and 111c. Conductive layers 112a, 112b, and 112c are provided on conductive layers 111a, 111b, and 111c and on layer 128, and are electrically connected to conductive layers 111a, 111b, and 111c. Therefore, regions overlapping with the recesses of conductive layers 111a, 111b, and 111c can also be used as light-emitting regions, thereby increasing the aperture ratio of the pixels.

[0475] Layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used for layer 128 as appropriate. In particular, it is preferable that layer 128 be formed using an insulating material.

[0476] As layer 128, an insulating layer having an organic material can be suitably used. For example, acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be used as layer 128. Alternatively, a photosensitive resin can be used as layer 128. The photosensitive resin can be a positive-type material or a negative-type material.

[0477] By using a photosensitive resin, layer 128 can be fabricated using only exposure and development processes, reducing the impact on the surfaces of conductive layers 111a, 111b, and 111c due to dry etching or wet etching. Furthermore, by forming layer 128 using a negative-type photosensitive resin, it may be possible to form layer 128 using the same photomask (exposure mask) used to form the openings of the insulating layer 214.

[0478] The top and side surfaces of conductive layer 112a and conductive layer 126a are covered by the first layer 113a. Similarly, the top and side surfaces of conductive layer 112b and conductive layer 126b are covered by the second layer 113b. Furthermore, the top and side surfaces of conductive layer 112c and conductive layer 126c are covered by the third layer 113c. Therefore, the entire region where conductive layers 112a, 112b, and 112c are provided can be used as the light-emitting region of light-emitting devices 130a, 130b, and 130c, thereby increasing the aperture ratio of the pixels.

[0479] The sides of the first layer 113a, the second layer 113b, and the third layer 113c are covered by 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. In addition, a protective layer 131 is provided on the light-emitting devices 130a, 130b, and 130c, respectively.

[0480] The protective layer 131 and the substrate 152 are bonded together via an adhesive layer 142. For sealing the light-emitting device, a solid sealing structure or a hollow sealing structure can be applied. In Figure 24A, the space between the substrate 152 and the substrate 151 is filled with the adhesive layer 142, demonstrating a solid sealing structure. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), demonstrating a hollow sealing structure. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting device. Furthermore, the space may be filled with a resin different from the adhesive layer 142, which is provided in a frame shape.

[0481] In the connection portion 140, a conductive layer 123 is provided on the insulating layer 214. The conductive layer 123 is shown as an example of a laminated structure consisting of a conductive film obtained by processing the same conductive film as conductive layers 111a, 111b, and 111c, a conductive film obtained by processing the same conductive film as conductive layers 112a, 112b, and 112c, and a conductive film obtained by processing the same conductive film as conductive layers 126a, 126b, and 126c. The ends of the conductive layer 123 are covered by a sacrificial layer 118a, an insulating layer 125, and an insulating layer 127. Furthermore, 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 via the fourth layer 114. Note that the fourth layer 114 does not necessarily have to be formed in the connection portion 140. In this case, the conductive layer 123 and the common electrode 115 are in direct contact and electrically connected.

[0482] The display device 100A is a top-emission type. The light emitted by the light-emitting device is emitted towards the substrate 152. It is preferable to use a material with high transmittance to visible light for the substrate 152. The pixel electrodes contain a material that reflects visible light, and the counter electrodes (common electrodes 115) contain a material that transmits visible light.

[0483] The laminated structure from the substrate 151 to the insulating layer 214 corresponds to the layer 101 containing the transistor in Embodiment 1.

[0484] Both transistors 201 and 205 are formed on the substrate 151. These transistors can be manufactured using the same materials and the same process.

[0485] On the substrate 151, insulating layers 211, 213, 215, and 214 are provided in this order. A portion of insulating layer 211 functions as a gate insulating layer for each transistor. A portion of insulating layer 213 functions as a gate insulating layer for each transistor. Insulating layer 215 is provided covering the transistors. Insulating layer 214 is provided covering the transistors and functions as a planarization layer. The number of gate insulating layers and insulating layers covering the transistors are not limited and may be a single layer or two or more layers, respectively.

[0486] It is preferable to use a material that does not easily allow impurities such as water and hydrogen to diffuse into at least one layer of the insulating layer covering the transistor. This allows the insulating layer to function as a barrier layer. With such a configuration, the diffusion of impurities from the outside into the transistor can be effectively suppressed, thereby improving the reliability of the display device.

[0487] It is preferable to use inorganic insulating films for insulating layer 211, insulating layer 213, and insulating layer 215. Examples of inorganic insulating films that can be used include silicon nitride film, silicon oxide nitride film, silicon oxide film, silicon nitride oxide film, aluminum oxide film, and aluminum nitride film. Alternatively, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, and neodymium oxide film may also be used. Furthermore, two or more of the above insulating films may be laminated together.

[0488] An organic insulating film is preferred for the insulating layer 214, which functions as a planarization layer. Examples of materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. Alternatively, the insulating layer 214 may have a laminated structure of an organic insulating film and an inorganic insulating film. The outermost layer of the insulating layer 214 preferably functions as an etching protective film. This makes it possible to suppress the formation of depressions in the insulating layer 214 during processing of conductive layers 111a, 112a, or 126a. Alternatively, depressions may be provided in the insulating layer 214 during processing of conductive layers 111a, 112a, or 126a.

[0489] Transistors 201 and 205 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as source and drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0490] The transistor structure of the display device of this embodiment is not particularly limited. For example, planar transistors, staggered transistors, inverse staggered transistors, etc., can be used. Furthermore, either a top-gate or bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below the semiconductor layer in which the channel is formed.

[0491] Transistors 201 and 205 are configured in which a semiconductor layer on which a channel is formed is sandwiched between two gates. The transistors may be driven by connecting the two gates and supplying them with the same signal. Alternatively, the threshold voltage of the transistors may be controlled by applying a potential to control the threshold voltage to one of the two gates and a potential to drive the other gate.

[0492] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, single-crystal semiconductors, or semiconductors with crystalline properties other than single crystals (microcrystalline semiconductors, polycrystalline semiconductors, or semiconductors with crystalline regions in part) may be used. Using a single-crystal semiconductor or a semiconductor with crystalline properties is preferable because it can suppress the degradation of transistor characteristics.

[0493] The semiconductor layer of the transistor preferably has a metal oxide (also called an oxide semiconductor). In other words, the display device of this embodiment preferably uses a transistor (hereinafter referred to as an OS transistor) that uses a metal oxide in the channel formation region. Alternatively, the semiconductor layer of the transistor may have silicon. Examples of silicon include amorphous silicon and crystalline silicon (low-temperature polysilicon, single-crystal silicon, etc.).

[0494] The semiconductor layer preferably comprises, for example, indium, M (where M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin.

[0495] In particular, it is preferable to use an oxide (also written as IGZO) containing indium (In), gallium (Ga), and zinc (Zn) as the semiconductor layer. Alternatively, it is preferable to use an oxide containing indium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc.

[0496] When the semiconductor layer is an In-M-Zn oxide, it is preferable that the atomic ratio of In in the In-M-Zn oxide is equal to or greater than the atomic ratio of M. Examples of such In-M-Zn oxide atomic ratios of metal elements include compositions where In:M:Zn=1:1:1 or close to it, In:M:Zn=1:1:1.2 or close to it, In:M:Zn=2:1:3 or close to it, In:M:Zn=3:1:2 or close to it, In:M:Zn=4:2:3 or close to it, In:M:Zn=4:2:4.1 or close to it, In:M:Zn=5:1:3 or close to it, In:M:Zn=5:1:6 or close to it, In:M:Zn=5:1:7 or close to it, In:M:Zn=5:1:8 or close to it, In:M:Zn=6:1:6 or close to it, In:M:Zn=5:2:5 or close to it, and so on. Note that "close to it" compositions include a range of ±30% of the desired atomic ratio.

[0497] For example, when describing a composition with an atomic ratio of In:Ga:Zn = 4:2:3 or a similar ratio, it includes cases where, when In is set to 4, Ga is between 1 and 3, and Zn is between 2 and 4. Also, when describing a composition with an atomic ratio of In:Ga:Zn = 5:1:6 or a similar ratio, it includes cases where, when In is set to 5, Ga is greater than 0.1 and 2 or less, and Zn is between 5 and 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn = 1:1:1 or a similar ratio, it includes cases where, when In is set to 1, Ga is greater than 0.1 and 2 or less, and Zn is greater than 0.1 and 2 or less.

[0498] The transistors in circuit 164 and the transistors in display unit 162 may have the same structure or different structures. The structures of the multiple transistors in circuit 164 may all be the same or there may be two or more different structures. Similarly, the structures of the multiple transistors in display unit 162 may all be the same or there may be two or more different structures.

[0499] Figures 24B and 24C show other examples of transistor configurations.

[0500] Transistors 209 and 210 each have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer 231 having a channel forming region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel forming region 231i. The insulating layer 225 is located at least between the conductive layer 223 and the channel forming region 231i. Furthermore, an insulating layer 218 covering the transistor may be provided.

[0501] In the transistor 209 shown in Figure 24B, an example is shown where the insulating layer 225 covers the top and sides of the semiconductor layer 231. The conductive layers 222a and 222b are connected to the low-resistance region 231n through openings provided in the insulating layers 225 and 215, respectively. Of the conductive layers 222a and 222b, one functions as the source and the other as the drain.

[0502] On the other hand, in the transistor 210 shown in Figure 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 structure shown in Figure 24C can be fabricated by processing the insulating layer 225 using the conductive layer 223 as a mask. In Figure 24C, an insulating layer 215 is provided covering the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and conductive layer 222b are connected to the low-resistance region 231n, respectively, through openings in the insulating layer 215.

[0503] A connection portion 204 is provided in the region of substrate 151 where substrate 152 does not overlap. At the connection portion 204, wiring 165 is electrically connected to FPC 172 via conductive layer 166 and connection layer 242. The conductive layer 166 is shown as an example of a laminated structure consisting of a conductive film obtained by processing the same conductive film as conductive layers 111a, 111b, and 111c, a conductive film obtained by processing the same conductive film as conductive layers 112a, 112b, and 112c, and a conductive film obtained by processing the same conductive film as conductive layers 126a, 126b, and 126c. The conductive layer 166 is exposed on the upper surface of the connection portion 204. This allows the connection portion 204 and FPC 172 to be electrically connected via the connection layer 242.

[0504] It is preferable to provide a light-shielding layer 117 on the surface of the substrate 152 that faces the substrate 151. The light-shielding layer 117 can be provided between adjacent light-emitting devices, at connection points 140, and in circuits 164, etc. Various optical components can be arranged on the outside of the substrate 152. Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (diffusion films, etc.), anti-reflective layers, and light-collecting films. Furthermore, an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, an impact-absorbing layer, etc., may be arranged on the outside of the substrate 152.

[0505] By providing a protective layer 131 that covers the light-emitting device, it is possible to suppress the ingress of impurities such as water into the light-emitting device and improve the reliability of the light-emitting device.

[0506] Substrates 151 and 152 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, etc., respectively. The substrate on the side that extracts light from the light-emitting device should be made of a material that transmits the light. Using flexible materials for substrates 151 and 152 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used as substrate 151 or substrate 152.

[0507] Substrates 151 and 152 can be made from polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. One or both of substrates 151 and 152 may be made of glass of a thickness sufficient to provide flexibility.

[0508] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy for the substrate of the display device. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence).

[0509] For substrates with high optical isotropy, the absolute value of the retardation (phase difference) is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0510] Examples of films with high optical isotropy include triacetylcellulose (TAC, also known as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0511] Furthermore, when using a film as the substrate, the film may absorb water, potentially causing wrinkles or other shape changes in the display panel. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferable to use a film with a water absorption rate of 0.1% or less, and even more preferable to use a film with a water absorption rate of 0.01% or less.

[0512] As the adhesive layer 142, various types of curing adhesives can be used, such as UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0513] As the connecting layer 242, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), etc., can be used.

[0514] Materials that can be used for conductive layers such as the gate, source, and drain of transistors, as well as various wirings and electrodes that constitute display devices, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys mainly composed of these metals. Films containing these materials can be used as single layers or in a multilayer structure.

[0515] Furthermore, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene can be used as the light-transmitting conductive material. Alternatively, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metallic materials, can be used. Alternatively, nitrides of such metallic materials (e.g., titanium nitride) may be used. When using metallic materials or alloy materials (or their nitrides), it is preferable to make them thin enough to be light-transmitting. In addition, a laminated film of the above materials can be used as a conductive layer. For example, using a laminated film of a silver-magnesium alloy and indium tin oxide is preferable because it can enhance conductivity. These can also be used as conductive layers for various wirings and electrodes that constitute a display device, and as conductive layers (conductive layers that function as pixel electrodes or common electrodes) in light-emitting devices.

[0516] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide, and aluminum oxide.

[0517] [Display device 100B] The display device 100B shown in Figure 25A differs from the display device 100A mainly in that it is a bottom-emission type display device that combines a white light-emitting device with a color filter. In the following description of the display device, parts that are the same as those described earlier may be omitted.

[0518] The light emitted by the light-emitting device is projected onto the substrate 151. It is preferable to use a material with high transparency to visible light for the substrate 151. On the other hand, the light transmittance of the material used for the substrate 152 is not a requirement.

[0519] It is preferable to form a light-shielding layer 117 between the substrate 151 and the transistor 201, and between the substrate 151 and the transistor 205. Figure 25A shows an example in which a light-shielding layer 117 is provided on the substrate 151, an insulating layer 153 is provided on the light-shielding layer 117, and transistors 201, 205, etc. are provided on the insulating layer 153.

[0520] The light-emitting device 130a and the colored layer 132R are superimposed, 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 are superimposed, 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.

[0521] Both light-emitting devices 130a and 130b can be configured to emit white light. In other words, the first layer 113a and the second layer 113b can have the same configuration. In Figure 25A, the first layer 113a and the second layer 113b are shown as three layers, and specifically, a laminated structure consisting 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 the example of the method for manufacturing a display device shown in Embodiment 1, Example 3.

[0522] Furthermore, while Figures 24A and 25A show examples where the upper surface of layer 128 has a flat portion, the shape of layer 128 is not particularly limited. Figures 25B to 25D show modified examples of layer 128.

[0523] As shown in Figures 25B and 25D, the upper surface of layer 128 can be configured to have a shape in which the center and its vicinity are recessed in a cross-sectional view, that is, a shape having a concave curved surface.

[0524] Furthermore, as shown in Figure 25C, the upper surface of layer 128 can be configured to have a shape that bulges in the center and its vicinity when viewed in cross-section, that is, a shape with a convex curved surface.

[0525] Furthermore, the upper surface of layer 128 may have one or both of a convex and a concave surface. Also, the number of convex and concave surfaces on the upper surface of layer 128 is not limited and can be one or more.

[0526] Furthermore, the height of the top surface of layer 128 and the height of the top surface of the conductive layer 111a may be the same or approximately the same, or they may be different from each other. For example, the height of the top surface of layer 128 may be lower or higher than the height of the top surface of the conductive layer 111a.

[0527] Furthermore, Figure 25B can be seen as an example in which layer 128 is housed inside a recess formed in the conductive layer 111a. On the other hand, as shown in Figure 25D, layer 128 may exist outside the recess formed in the conductive layer 111a, that is, the width of the upper surface of layer 128 may be wider than that of the recess.

[0528] [Display device 100C] The display device 100C shown in Figure 26 differs from the display device 100A mainly in that it uses a tandem structure light-emitting device.

[0529] In Figure 26, the first layer 113a, the second layer 113b, and the third layer 113c are each shown as three layers, and specifically, a laminated structure consisting of a first light-emitting unit, a charge generation layer, and a second light-emitting unit can be applied.

[0530] For example, the display device 100C can be configured as shown in Figure 18C, which was described in Embodiment 2. Specifically, the first layer 113a can be configured in which a second light-emitting unit having a red light-emitting layer is laminated on top of a first light-emitting unit having a red light-emitting layer. Similarly, the second layer 113b can be configured in which a second light-emitting unit having a green light-emitting layer is laminated on top of a first light-emitting unit having a green light-emitting layer. Furthermore, the third layer 113c can be configured in which a second light-emitting unit having a blue light-emitting layer is laminated on top of a first light-emitting unit having a blue light-emitting layer.

[0531] By using tandem-structured light-emitting devices, the brightness of a display device can be increased. Alternatively, the current required to achieve the same brightness can be reduced, thereby improving the reliability of the display device.

[0532] [Display device 100D] The display device 100D shown in Figure 27 differs from the display device 100A mainly in that it has a light receiving device 130d.

[0533] The light-receiving device 130d includes a conductive layer 111d, a conductive layer 112d on the conductive layer 111d, and a conductive layer 126d on the conductive layer 112d.

[0534] The conductive layer 111d is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214.

[0535] The top and side surfaces of conductive layer 112d and conductive layer 126d are covered by a fifth layer 113d. The fifth layer 113d has at least an active layer.

[0536] The sides of the fifth layer 113d are covered by 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 both the light-receiving device and the light-emitting device.

[0537] The display device 100D can, for example, employ the pixel layout shown in Figures 6A to 6D, as described in Embodiment 1. The light-receiving device 130d can be provided in the sub-pixel PS or sub-pixel IRS. For further details of the display device having a light-receiving device, refer to Embodiment 1.

[0538] This embodiment can be combined with other embodiments as appropriate.

[0539] (Embodiment 4) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 28 to 33.

[0540] The display device of this embodiment can be a high-definition display device. Therefore, the display device of this embodiment can be used in the display section of wearable devices that can be worn on the head, such as information terminals (wearable devices) such as wristwatches and bracelets, as well as VR devices such as head-mounted displays and AR devices such as glasses.

[0541] [Display Module] Figure 28A shows a perspective view of the 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, but may be any of the display devices 100F to 100L described later.

[0542] The display module 280 has substrates 291 and 292. The display module 280 has a display unit 281. The display unit 281 is an area in the display module 280 that displays an image, and is an area in which light from each pixel provided in the pixel unit 284, which will be described later, can be seen.

[0543] Figure 28B shows a schematic perspective view illustrating the configuration of the substrate 291. On the substrate 291, a circuit section 282, a pixel circuit section 283 on the circuit section 282, and a pixel section 284 on the pixel circuit section 283 are stacked. In addition, a terminal section 285 for connecting to the FPC 290 is provided in the portion of the substrate 291 that does not overlap with the pixel section 284. The terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286, which is composed of multiple wires.

[0544] The pixel section 284 has multiple pixels 284a arranged periodically. A magnified view of a single pixel 284a is shown on the right side of Figure 28B. Each pixel 284a has light-emitting devices 130a, 130b, and 130c, each with a different emission color. The multiple light-emitting devices can be arranged in a stripe pattern as shown in Figure 28B. Various arrangement methods for the light-emitting devices, such as a delta pattern or a pentile pattern, can also be applied.

[0545] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0546] A single pixel circuit 283a is a circuit that controls the light emission of three light-emitting devices in a single pixel 284a. A single pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting device. For example, a pixel circuit 283a can be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitive element for each light-emitting device. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to the source. This realizes an active-matrix type display device.

[0547] The circuit section 282 has circuits for driving each pixel circuit 283a of the pixel circuit section 283. For example, it is preferable to have one or both of a gate line drive circuit and a source line drive circuit. In addition, it may have at least one of the following: an arithmetic circuit, a memory circuit, and a power supply circuit.

[0548] The FPC290 functions as wiring for supplying video signals or power potential, etc., to the circuit section 282 from an external source. An IC may also be mounted on the FPC290.

[0549] The display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are superimposed on the lower side of the pixel section 284, thereby enabling an extremely high aperture ratio (effective display area ratio) of the display section 281. For example, the aperture ratio of the display section 281 can be 40% or more and less than 100%, preferably 50% or more and 95%, and more preferably 60% or more and 95%. Furthermore, it is possible to arrange the pixels 284a at an extremely high density, enabling an extremely high resolution of the display section 281. For example, it is preferable that the pixels 284a in the display section 281 are arranged with a resolution of 20000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and with a resolution of 20000 ppi or less, or 30000 ppi or less.

[0550] Because such a display module 280 is extremely high-resolution, it can be suitably used in VR devices such as head-mounted displays, or in glasses-type AR devices. For example, even in a configuration where the display part of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display part 281, so even when the display part is magnified with lenses, pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 280 is not limited to this, and can be suitably used in electronic devices with relatively small display parts. For example, it can be suitably used in the display part of wearable electronic devices such as wristwatches.

[0551] [Display device 100E] The display device 100E shown in Figure 29A comprises a substrate 301, light-emitting devices 130a, 130b, and 130c, a capacitor 240, and a transistor 310.

[0552] Substrate 301 corresponds to substrate 291 in Figures 28A and 28B. The laminated structure from substrate 301 to insulating layer 255b corresponds to layer 101 containing the transistor in Embodiment 1.

[0553] The transistor 310 is a transistor having a channel-forming region in the substrate 301. The substrate 301 can be a semiconductor substrate such as a single-crystal silicon substrate. The transistor 310 comprises a portion of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region of the substrate 301 doped with impurities and functions as either a source or a drain. The insulating layer 314 is provided covering the side surface of the conductive layer 311.

[0554] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0555] Furthermore, an insulating layer 261 is provided covering the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0556] Capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located between them. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as the dielectric of the capacitor 240.

[0557] The conductive layer 241 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is electrically connected to either the source or drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided covering the conductive layer 241. The conductive layer 245 is provided in the region that overlaps with the conductive layer 241 via the insulating layer 243.

[0558] An insulating layer 255a is provided covering the capacitance 240, an insulating layer 255b is provided on the insulating layer 255a, and light-emitting devices 130a, 130b, 130c, etc. are provided on the insulating layer 255b. In this embodiment, an example is shown in which the light-emitting devices 130a, 130b, and 130c have a structure similar to the laminated structure shown in Figure 1B. The sides of the first layer 113a, the second layer 113b, and the third layer 113c are covered by insulating layers 125 and 127, respectively.

[0559] Furthermore, a sacrificial layer 118a is located on the first layer 113a. One end of the sacrificial layer 118a is aligned with or approximately aligned with the 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 aligned with or approximately aligned with the 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 aligned with or approximately aligned with the 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 also 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. Details of the components from the light-emitting devices to the substrate 120 can be found in Embodiment 1. The substrate 120 corresponds to the substrate 292 in Figure 28A.

[0560] Various inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride-oxide insulating films can be suitably used as insulating layers 255a and 255b, respectively. For insulating layer 255a, it is preferable to use an oxide insulating film or oxidative nitride insulating film such as a silicon oxide film, silicon oxidative nitride film, or aluminum oxide film. For insulating layer 255b, it is preferable to use a nitride insulating film or oxidative nitride insulating film such as a silicon nitride film or silicon nitride-oxide film. More specifically, it is preferable to use a silicon oxide film as insulating layer 255a and a silicon nitride film as insulating layer 255b. It is preferable that insulating layer 255b functions as an etching protective film. Alternatively, a nitride insulating film or nitride-oxide insulating film may be used as insulating layer 255a, and an oxide insulating film or oxidative nitride insulating film may be used as insulating layer 255b. In this embodiment, an example is shown in which a recess is provided in the insulating layer 255b, but the insulating layer 255b does not necessarily have to have a recess.

[0561] The pixel electrodes of the light-emitting device are electrically connected to either the source or drain of the transistor 310 by plugs 256 embedded in insulating layers 255a and 255b, a conductive layer 241 embedded in insulating layer 254, and a plug 271 embedded in insulating layer 261. The height of the upper surface of insulating layer 255b and the height of the upper surface of plug 256 are equal or approximately equal. Various conductive materials can be used for the plugs.

[0562] [Display device 100F] The display device 100F shown in Figure 29B is an example in which colored layers 132R, 132G, and 132B are provided on the protective layer 131. In the following description of the display device, parts that are the same as those described earlier may be omitted.

[0563] The light-emitting device 130a and the colored layer 132R are superimposed, and the 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 are superimposed, and the 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 are superimposed, and the 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.

[0564] Figure 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. However, as shown in Figure 29A, the first layer 113a, the second layer 113b, and the third layer 113c may each have different configurations.

[0565] The substrate 120 is bonded to the colored layers 132R, 132G, and 132B by a resin layer 122.

[0566] [Display device 100G] The display device 100G shown in Figure 29C is an example in which a substrate 120, on which colored layers 132R, 132G, and 132B are provided, is bonded to a protective layer 131 by a resin layer 122.

[0567] [Display device 100H] The display device 100H shown in Figure 30 differs from the display device 100E mainly in its transistor configuration.

[0568] Transistor 320 is an OS transistor in which a metal oxide (also called an oxide semiconductor) is applied to the semiconductor layer where the channel is formed.

[0569] The transistor 320 has a semiconductor layer 321, an insulating layer 323, a conductive layer 324, a pair of conductive layers 325, an insulating layer 326, and a conductive layer 327.

[0570] Substrate 331 corresponds to substrate 291 in Figures 28A and 28B. The laminated structure from substrate 331 to insulating layer 255b corresponds to layer 101 containing the transistor in Embodiment 1. An insulating substrate or a semiconductor substrate can be used as substrate 331.

[0571] An insulating layer 332 is provided on the substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320, and prevents oxygen from detaching from the semiconductor layer 321 to the insulating layer 332. As the insulating layer 332, for example, a film that is less susceptible to hydrogen or oxygen diffusion than a silicon oxide film can be used, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0572] A conductive layer 327 is provided on an insulating layer 332, and an insulating layer 326 is provided covering the conductive layer 327. The conductive layer 327 functions as the first gate electrode of the transistor 320, and a portion of the insulating layer 326 functions as the first gate insulating layer. It is preferable to use an oxide insulating film, such as a silicon oxide film, for at least the portion of the insulating layer 326 that is in contact with the semiconductor layer 321. It is preferable that the upper surface of the insulating layer 326 is flattened.

[0573] The semiconductor layer 321 is provided on the insulating layer 326. Preferably, the semiconductor layer 321 has a metal oxide (also called an oxide semiconductor) film having semiconductor properties. Details of materials suitable for use in the semiconductor layer 321 will be described later.

[0574] A pair of conductive layers 325 are provided in contact with the semiconductor layer 321 and function as source and drain electrodes.

[0575] Furthermore, an insulating layer 328 is provided covering the top and side surfaces of the pair of conductive layers 325, as well as the side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided on the insulating layer 328. The insulating layer 328 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing into the semiconductor layer 321 from the insulating layer 264, etc., and to prevent oxygen from detaching from the semiconductor layer 321. As the insulating layer 328, an insulating film similar to that of the insulating layer 332 can be used.

[0576] An opening is provided in the insulating layer 328 and the insulating layer 264 that reaches the semiconductor layer 321. Inside this opening, the insulating layer 323 and the conductive layer 324 are embedded, in contact with the sides of the insulating layer 264, the insulating layer 328, and the conductive layer 325, as well as the upper surface of the semiconductor layer 321. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0577] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are flattened so that their heights are the same or approximately the same, and the insulating layer 329 and insulating layer 265 are provided covering them.

[0578] Insulating layers 264 and 265 function as interlayer insulating layers. Insulating layer 329 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing into the transistor 320 from insulating layer 265, etc. As insulating layer 329, an insulating film similar to that used for insulating layers 328 and 332 can be used.

[0579] A plug 274, which is electrically connected to one of the pair of conductive layers 325, is provided so as to be embedded in the insulating layers 265, 329, and 264. Here, it is preferable that the plug 274 has a conductive layer 274a that covers the sides of the openings of the insulating layers 265, 329, 264, and 328, and a part of the upper surface of the conductive layer 325, and a conductive layer 274b that is in contact with the upper surface of the conductive layer 274a. In this case, it is preferable to use a conductive material that does not easily allow hydrogen and oxygen to diffuse as the conductive layer 274a.

[0580] 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.

[0581] [Display device 100J] The display device 100J shown in Figure 31 has a configuration in which a transistor 310 with a channel formed on a substrate 301 and a transistor 320 containing a metal oxide in the semiconductor layer where the channel is formed are stacked.

[0582] An insulating layer 261 is provided covering the transistor 310, and a conductive layer 251 is provided on the insulating layer 261. An insulating layer 262 is provided covering the conductive layer 251, and a conductive layer 252 is provided on the insulating layer 262. The conductive layers 251 and 252 each function as wiring. An insulating layer 263 and an insulating layer 332 are provided covering the conductive layer 252, and a transistor 320 is provided on the insulating layer 332. An insulating layer 265 is provided covering the transistor 320, and a capacitor 240 is provided on the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0583] Transistor 320 can be used as a transistor constituting a pixel circuit. Transistor 310 can also be used as a transistor constituting a pixel circuit, or as a transistor constituting a drive circuit (gate line drive circuit, source line drive circuit) for driving the pixel circuit. Furthermore, transistors 310 and 320 can be used as transistors constituting various circuits such as arithmetic circuits or memory circuits.

[0584] This configuration allows for the formation of not only pixel circuits but also drive circuits directly beneath the light-emitting device, making it possible to miniaturize the display device compared to cases where the drive circuits are located around the display area.

[0585] [Display device 100K] The display device 100K shown in Figure 32 has a configuration in which transistors 310A and 310B, each with a channel formed on a semiconductor substrate, are stacked.

[0586] The display device 100K has a configuration in which a substrate 301B on which transistor 310B, capacitor 240, and each light-emitting device are provided, and a substrate 301A on which transistor 310A is provided are bonded together.

[0587] Here, it is preferable to provide an insulating layer 345 on the lower surface of substrate 301B. It is also preferable to provide an insulating layer 346 on top of the insulating layer 261 provided on substrate 301A. Insulating layers 345 and 346 are insulating layers that function as protective layers and can suppress the diffusion of impurities into substrates 301B and 301A. As insulating layers 345 and 346, inorganic insulating films that can be used for protective layer 131 or insulating layer 332 can be used.

[0588] A plug 343 is provided on the substrate 301B, penetrating both the substrate 301B and the insulating layer 345. It is preferable to provide an insulating layer 344 covering the sides of the plug 343. The insulating layer 344 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.

[0589] Furthermore, a conductive layer 342 is provided on the back side of the substrate 301B (the side opposite to the substrate 120 side), beneath the insulating layer 345. Preferably, the conductive layer 342 is provided so as to be embedded in the insulating layer 335. Also, preferably, the undersides of the conductive layer 342 and the insulating layer 335 are flattened. Here, the conductive layer 342 is electrically connected to the plug 343.

[0590] On the other hand, the substrate 301A has a conductive layer 341 provided on an insulating layer 346. Preferably, the conductive layer 341 is provided so as to be embedded in the insulating layer 336. Furthermore, it is preferable that the upper surfaces of the conductive layer 341 and the insulating layer 336 are flattened.

[0591] The conductive layer 341 and the conductive layer 342 are bonded together, thereby electrically connecting the substrate 301A and the substrate 301B. 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 bonding of the conductive layer 341 and the conductive layer 342 can be improved.

[0592] It is preferable to use the same conductive material for conductive layer 341 and conductive layer 342. For example, a metal film containing an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, or a metal nitride film (titanium nitride film, molybdenum nitride film, tungsten nitride film) composed of the above elements can be used. In particular, it is preferable to use copper for conductive layer 341 and conductive layer 342. This makes it possible to apply Cu-Cu (copper-copper) direct bonding technology (a technology that achieves electrical conductivity by connecting Cu (copper) pads to each other).

[0593] [Display device 100L] Figure 32 shows an example in which Cu-Cu direct bonding technology is used to bond conductive layer 341 and conductive layer 342, but the present invention is not limited to this. As shown in the display device 100L in Figure 33, the conductive layer 341 and conductive layer 342 may be bonded via bumps 347.

[0594] As shown in Figure 33, the conductive layer 341 and the conductive layer 342 can be electrically connected by providing a bump 347 between them. The bump 347 can be formed using a conductive material containing, for example, gold (Au), nickel (Ni), indium (In), or tin (Sn). Solder may also be used as the bump 347. An adhesive layer 348 may also be provided between the insulating layer 345 and the insulating layer 346. Furthermore, when the bump 347 is provided, the insulating layer 335 and the insulating layer 336 may be omitted.

[0595] This embodiment can be combined with other embodiments as appropriate.

[0596] (Embodiment 5) This embodiment describes an example of a transistor configuration that can be applied to a display device according to one aspect of the present invention. In particular, it describes a case in which a transistor containing silicon is used as the semiconductor in which the channel is formed.

[0597] One aspect of the present invention is a display device having a light-emitting device and a pixel circuit. The display device can be a full-color display device by having, for example, three types of light-emitting devices that emit red (R), green (G), or blue (B) light, respectively.

[0598] It is preferable to use transistors in which the semiconductor layer in which the channel is formed is silicon for all transistors included in the pixel circuit that drives the light-emitting device. Examples of silicon include single-crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, it is preferable to use transistors in which the semiconductor layer is low-temperature polysilicon (LTPS (Low Temperature Poly Silicon)) (hereinafter also referred to as LTPS transistors). LTPS transistors have high field-effect mobility and good frequency characteristics.

[0599] By using silicon-based transistors such as LTPS transistors, circuits that need to be driven at high frequencies (e.g., source driver circuits) can be fabricated on the same board as the display unit. This simplifies the external circuits implemented in the display device, reducing component and mounting costs.

[0600] Furthermore, it is preferable to use a transistor (hereinafter also called an OS transistor) in which a metal oxide (hereinafter also called an oxide semiconductor) is used as the semiconductor in which the channel is formed. OS transistors have extremely high field-effect mobility compared to amorphous silicon. In addition, OS transistors have a remarkably small source-drain leakage current (hereinafter also called an off-current) in the off state, and can retain the charge stored in a capacitor connected in series with the transistor for a long period of time. Moreover, by applying OS transistors, the power consumption of the display device can be reduced.

[0601] By using LTPS transistors in some of the transistors included in the pixel circuit and OS transistors in others, a display device with low power consumption and high driving capability can be realized. Furthermore, a configuration combining LTPS transistors and OS transistors is sometimes referred to as LTPO. A more preferable example is to apply OS transistors to transistors that function as switches to control conduction and non-conduction between wiring, and LTPS transistors to transistors that control current.

[0602] For example, one of the transistors provided in the pixel circuit functions as a transistor for controlling the current flowing to the light-emitting device, and can also be called a drive transistor. One of the source and drain of the drive transistor is electrically connected to the pixel electrode of the light-emitting device. It is preferable to use an LTPS transistor for this drive transistor. This makes it possible to increase the current flowing to the light-emitting device in the pixel circuit.

[0603] On the other hand, another transistor provided in the pixel circuit functions as a switch to control the selection and deselection of pixels, and can also be called a selection transistor. The gate of the selection transistor is electrically connected to the gate line, and one of the source and drain is electrically connected to the source line (signal line). It is preferable to use an OS transistor for the selection transistor. This makes it possible to maintain the gradation of pixels even when the frame frequency is significantly reduced (e.g., 1 fps or less), and thus power consumption can be reduced by stopping the driver when displaying still images.

[0604] Below, we will explain more specific configuration examples with reference to the drawings.

[0605] [Example of display device configuration 2] Figure 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.

[0606] 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.

[0607] Pixel 30 is electrically connected to wiring GL, wiring SLR, wiring SLG, and wiring SLB. Wiring SLR, wiring SLG, and wiring SLB are each electrically connected to the drive circuit unit 12. Wiring GL is electrically connected to the drive circuit unit 13. The drive circuit unit 12 functions as a source line drive circuit (also called a source driver), and the drive circuit unit 13 functions as a gate line drive circuit (also called a gate driver). Wiring GL functions as a gate line, and wiring SLR, wiring SLG, and wiring SLB each function as source lines.

[0608] Sub-pixel 21R has a light-emitting device that emits red light. Sub-pixel 21G has a light-emitting device that emits green light. Sub-pixel 21B has a light-emitting device that emits blue light. This allows the display device 10 to display in full color. Note that pixel 30 may have sub-pixels that emit light-emitting devices of other colors. For example, in addition to the three sub-pixels described above, pixel 30 may have a sub-pixel that emits white light, or a sub-pixel that emits yellow light, and so on.

[0609] Wiring GL is electrically connected to sub-pixels 21R, 21G, and 21B, which are arranged in the row direction (the direction in which wiring GL extends). Wirings SLR, SLG, and SLB are electrically connected to sub-pixels 21R, 21G, or 21B (not shown), which are arranged in the column direction (the direction in which wiring SLR, etc. extends).

[0610] [Example of pixel circuit configuration] Figure 34B shows an example of a circuit diagram of a pixel 21 that can be applied to the sub-pixels 21R, 21G, and 21B described above. The pixel 21 has transistors M1, M2, M3, capacitor C1, and light-emitting device EL. Wiring GL and wiring SL are electrically connected to the pixel 21. Wiring SL corresponds to one of the wirings SLR, SLG, and SLB shown in Figure 34A.

[0611] Transistor M1 has its gate electrically connected to wiring GL, one of its source and drain electrically connected to wiring SL, and the other of its source and drain electrically connected to one electrode of capacitor C1 and the gate of transistor M2. Transistor M2 has one of its source and drain electrically connected to wiring AL, and the other of its source and drain electrically connected to one electrode of light-emitting device EL, the other electrode of capacitor C1, and one of its source and drain. Transistor M3 has its gate electrically connected to wiring GL, and the other of its source and drain electrically connected to wiring RL. Light-emitting device EL has its other electrode electrically connected to wiring CL.

[0612] A data potential is supplied to wiring SL. A selection signal is supplied to wiring GL. This selection signal includes a potential that makes the transistor conduct and a potential that makes it non-conductive.

[0613] A reset potential is applied to wiring RL. An anode potential is applied to wiring AL. A cathode potential is applied to wiring CL. In pixel 21, the anode potential is set to a potential higher than the cathode potential. The reset potential applied to wiring RL can be set to a potential such that the potential difference between the reset potential and the cathode potential is smaller than the threshold voltage of the light-emitting device EL. The reset potential can be set to a potential higher than the cathode potential, the same as the cathode potential, or lower than the cathode potential.

[0614] Transistors M1 and M3 function as switches. Transistor M2 functions as a transistor for controlling the current flowing to the light-emitting device EL. For example, it can be said that transistor M1 functions as a selector transistor and transistor M2 functions as a drive transistor.

[0615] Here, it is preferable to apply LTPS transistors to all of transistors M1 through M3. Alternatively, it is preferable to apply OS transistors to transistors M1 and M3 and an LTPS transistor to transistor M2.

[0616] Alternatively, OS transistors may be applied to all of transistors M1 through M3. In this case, one or more of the transistors in the drive circuit unit 12 and the drive circuit unit 13 may be LTPS transistors, and the other transistors may be OS transistors. For example, OS transistors may be applied to the transistors provided in the display unit 11, and LTPS transistors may be applied to the transistors provided in the drive circuit unit 12 and the drive circuit unit 13.

[0617] As an OS transistor, a transistor using an oxide semiconductor in the semiconductor layer where the channel is formed can be used. The semiconductor layer preferably contains, for example, indium, M (where M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, it is preferable that M is one or more selected from aluminum, gallium, yttrium, and tin. In particular, it is preferable to use an oxide containing indium, gallium, and zinc (also written as IGZO) as the semiconductor layer of the OS transistor. Alternatively, it is preferable to use an oxide containing indium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc.

[0618] Transistors using oxide semiconductors, which have a wider bandgap and lower carrier concentration than silicon, can achieve extremely small off-currents. Therefore, this small off-current allows the charge stored in a capacitor connected in series with the transistor to be retained for extended periods. For this reason, it is preferable to use transistors made of oxide semiconductors for transistors M1 and M3, which are connected in series with capacitor C1. By using transistors with oxide semiconductors as transistors M1 and M3, it is possible to prevent the charge held in capacitor C1 from leaking through transistor M1 or M3. Furthermore, because the charge held in capacitor C1 can be retained for extended periods, it becomes possible to display still images for extended periods without rewriting the data in pixel 21.

[0619] Note that in Figure 34B, the transistor is shown as an n-channel type transistor, but a p-channel type transistor can also be used.

[0620] Furthermore, it is preferable that each transistor in the pixel 21 be formed in a row on the same substrate.

[0621] As the transistor in pixel 21, a transistor having a pair of gates that overlap across a semiconductor layer can be applied.

[0622] In a transistor having a pair of gates, configuring the pair of gates to be electrically connected to each other and given the same potential offers advantages such as increased on-current and improved saturation characteristics. Alternatively, one of the pair of gates may be given a potential that controls the transistor's threshold voltage. Furthermore, providing a constant potential to one of the pair of gates can improve the stability of the transistor's electrical characteristics. For example, one of the transistor's gates may be electrically connected to a wiring to which a constant potential is provided, or it may be electrically connected to its own source or drain.

[0623] The pixel 21 shown in Figure 34C is an example where transistors M1 and M3 each have a pair of gates. The pair of gates of transistors M1 and M3 are electrically connected. This configuration shortens the data writing time to the pixel 21.

[0624] The pixel 21 shown in Figure 34D is an example in which a transistor with a pair of gates is applied to transistor M2, in addition to transistors M1 and M3. In transistor M2, the pair of gates are electrically connected. By applying such a transistor to transistor M2, the saturation characteristics are improved, making it easier to control the luminescence brightness of the light-emitting device EL and improving the display quality.

[0625] [Example of transistor configuration] The following describes examples of transistor cross-sectional configurations that can be applied to the above-mentioned display device.

[0626] [Configuration Example 1] Figure 35A is a cross-sectional view including transistor 410.

[0627] Transistor 410 is a transistor provided on substrate 401, with polycrystalline silicon applied to its semiconductor layer. For example, transistor 410 corresponds to transistor M2 of pixel 21. That is, Figure 35A shows an example where one of the source and drain of transistor 410 is electrically connected to the conductive layer 431 of the light-emitting device.

[0628] The transistor 410 has a semiconductor layer 411, an insulating layer 412, a conductive layer 413, etc. The semiconductor layer 411 has a channel-forming region 411i and a low-resistance region 411n. The semiconductor layer 411 is made of silicon. Preferably, the semiconductor layer 411 is made of polycrystalline silicon. A portion of the insulating layer 412 functions as a gate insulating layer. A portion of the conductive layer 413 functions as a gate electrode.

[0629] Furthermore, the semiconductor layer 411 may also be configured to include a metal oxide (also called an oxide semiconductor) that exhibits semiconductor properties. In this case, the transistor 410 can be called an OS transistor.

[0630] The low-resistance region 411n is a region containing impurity elements. For example, if transistor 410 is an n-channel type transistor, phosphorus, arsenic, etc., can be added to the low-resistance region 411n. On the other hand, if it is a p-channel type transistor, boron, aluminum, etc., can be added to the low-resistance region 411n. Furthermore, in order to control the threshold voltage of transistor 410, the aforementioned impurities may also be added to the channel formation region 411i.

[0631] An insulating layer 421 is provided on the substrate 401. The semiconductor layer 411 is provided on the insulating layer 421. The insulating layer 412 is provided covering the semiconductor layer 411 and the insulating layer 421. The conductive layer 413 is provided on the insulating layer 412 in a position overlapping with the semiconductor layer 411.

[0632] Furthermore, an insulating layer 422 is provided covering the conductive layer 413 and the insulating layer 412. Conductive layers 414a and 414b are provided on the insulating layer 422. Conductive layers 414a and 414b are electrically connected to the low-resistance region 411n at openings provided in the insulating layers 422 and 412. A portion of the conductive layer 414a functions as one of the source electrode and drain electrode, and a portion of the conductive layer 414b functions as the other of the source electrode and drain electrode. In addition, an insulating layer 423 is provided covering the conductive layer 414a, conductive layer 414b, and insulating layer 422.

[0633] A conductive layer 431, which functions as a pixel electrode, is provided on the insulating layer 423. The conductive layer 431 is provided on the insulating layer 423 and is electrically connected to the conductive layer 414b at an opening provided in the insulating layer 423. Although not shown here, an EL layer and a common electrode can be laminated on the conductive layer 431.

[0634] [Configuration Example 2] Figure 35B shows a transistor 410a having a pair of gate electrodes. The transistor 410a shown in Figure 35B differs from that in Figure 35A mainly in that it has a conductive layer 415 and an insulating layer 416.

[0635] The conductive layer 415 is provided on the insulating layer 421. Furthermore, an insulating layer 416 is provided covering the conductive layer 415 and the insulating layer 421. The semiconductor layer 411 is provided such that at least the channel-forming region 411i overlaps with the conductive layer 415 via the insulating layer 416.

[0636] In the transistor 410a shown in Figure 35B, a portion of the conductive layer 413 functions as a first gate electrode, and a portion of the conductive layer 415 functions as a second gate electrode. At the same time, a portion of the insulating layer 412 functions as a first gate insulating layer, and a portion of the insulating layer 416 functions as a second gate insulating layer.

[0637] Here, when electrically connecting the first gate electrode and the second gate electrode, the conductive layer 413 and the conductive layer 415 may be electrically connected through openings provided in the insulating layer 412 and the insulating layer 416 in a region not shown. Also, when electrically connecting the second gate electrode to the source or drain, the conductive layer 414a or conductive layer 414b and the conductive layer 415 may be electrically connected through openings provided in the insulating layer 422, the insulating layer 412, and the insulating layer 416 in a region not shown.

[0638] When LTPS transistors are applied to all transistors constituting pixel 21, transistor 410 as exemplified in Figure 35A, or transistor 410a as exemplified in Figure 35B, can be applied. In this case, transistor 410a may be used for all transistors constituting pixel 21, transistor 410 may be applied to all transistors, or transistor 410a and transistor 410 may be used in combination.

[0639] [Configuration Example 3] The following describes an example of a configuration that includes both transistors with silicon semiconductor layers and transistors with metal oxide semiconductor layers.

[0640] Figure 35C shows a schematic cross-sectional view including transistors 410a and 450.

[0641] For transistor 410a, the above configuration example 1 can be used. Although an example using transistor 410a is shown here, a configuration with transistor 410 and transistor 450 is also possible, or a configuration with all of transistors 410, 410a, and 450 is also possible.

[0642] Transistor 450 is a transistor in which a metal oxide is applied to the semiconductor layer. The configuration shown in Figure 35C is an example in which, for example, transistor 450 corresponds to transistor M1 of pixel 21 and transistor 410a corresponds to transistor M2. That is, Figure 35C is an example in which one of the source and drain of transistor 410a is electrically connected to the conductive layer 431.

[0643] Figure 35C also shows an example where transistor 450 has a pair of gates.

[0644] The transistor 450 has a conductive layer 455, an insulating layer 422, a semiconductor layer 451, an insulating layer 452, a conductive layer 453, etc. A portion of the conductive layer 453 functions as the first gate of the transistor 450, and a portion of the conductive layer 455 functions as the second gate of the transistor 450. At this time, a portion of the insulating layer 452 functions as the first gate insulating layer of the transistor 450, and a portion of the insulating layer 422 functions as the second gate insulating layer of the transistor 450.

[0645] The conductive layer 455 is provided on the insulating layer 412. The insulating layer 422 covers the conductive layer 455. The semiconductor layer 451 is provided on the insulating layer 422. The insulating layer 452 covers the semiconductor layer 451 and the insulating layer 422. The conductive layer 453 is provided on the insulating layer 452 and has a region that overlaps with the semiconductor layer 451 and the conductive layer 455.

[0646] Furthermore, an insulating layer 426 is provided covering the insulating layer 452 and the conductive layer 453. Conductive layers 454a and 454b are provided on the insulating layer 426. Conductive layers 454a and 454b are electrically connected to the semiconductor layer 451 at openings provided in the insulating layer 426 and the insulating layer 452. A portion of the conductive layer 454a functions as one of the source electrode and drain electrode, and a portion of the conductive layer 454b functions as the other of the source electrode and drain electrode. In addition, an insulating layer 423 is provided covering the conductive layer 454a, the conductive layer 454b, and the insulating layer 426.

[0647] Here, it is preferable that the conductive layers 414a and 414b, which are electrically connected to the transistor 410a, are formed by processing the same conductive film as conductive layers 454a and 454b. Figure 35C shows a configuration in which conductive layers 414a, 414b, 454a, and 454b are formed on the same plane (i.e., in contact with the upper surface of the insulating layer 426) and contain the same metal element. In this case, conductive layers 414a and 414b are electrically connected to the low-resistance region 411n through openings provided in the insulating layer 426, insulating layer 452, insulating layer 422, and insulating layer 412. This is preferable because it simplifies the manufacturing process.

[0648] Furthermore, it is preferable that the conductive layer 413, which functions as the first gate electrode of transistor 410a, and the conductive layer 455, which functions as the second gate electrode of transistor 450, are formed by processing the same conductive film. Figure 35C shows a configuration in which the conductive layer 413 and the conductive layer 455 are formed on the same plane (i.e., in contact with the upper surface of the insulating layer 412) and contain the same metal element. This is preferable because it simplifies the manufacturing process.

[0649] In Figure 35C, the insulating layer 452, which functions as the first gate insulating layer of the transistor 450, is configured to cover the edge of the semiconductor layer 451. However, as shown in Figure 35D, the insulating layer 452 may be processed so that its upper surface shape matches or roughly matches that of the conductive layer 453.

[0650] In this specification, "approximately matching top surface shapes" means that at least a portion of the contours overlap between stacked layers. For example, this includes cases where the upper and lower layers are processed with the same mask pattern, or partially with the same mask pattern. However, strictly speaking, the contours may not overlap, and the upper layer may be located inside the lower layer, or the upper layer may be located outside the lower layer; in this case, too, it is said that the "top surface shapes are approximately matching."

[0651] In this example, transistor 410a corresponds to transistor M2 and is electrically connected to the pixel electrode, but this is not the only example. For example, transistor 450 or transistor 450a may correspond to transistor M2. In this case, transistor 410a corresponds to transistor M1, transistor M3, or another transistor.

[0652] This embodiment can be combined with other embodiments as appropriate.

[0653] (Embodiment 6) This embodiment describes metal oxides (also called oxide semiconductors) that can be used in the OS transistor described in the above embodiment.

[0654] The metal oxide preferably contains at least indium or zinc. It is particularly preferable that it contains indium and zinc. In addition, it is preferable that it contains aluminum, gallium, yttrium, tin, etc. It may also contain one or more selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, etc.

[0655] Furthermore, metal oxides can be formed by methods such as sputtering, chemical vapor deposition (CVD) methods including metal-organic chemical vapor deposition (MOCVD), or atomic layer deposition (ALD).

[0656] <Classification of crystal structures> Examples of crystalline structures for oxide semiconductors include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and polycrystal.

[0657] The crystal structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectroscopy. For example, it can be evaluated using the XRD spectrum obtained by GIXD (Grazing-Incidence XRD) measurement. The GIXD method is also known as the thin-film method or the Seemann-Bohlin method.

[0658] For example, in a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, in an IGZO film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical shape of the XRD spectrum peak clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0659] Furthermore, the crystalline structure of a film or substrate can be evaluated by the diffraction pattern (also called the nano-beam electron diffraction pattern) observed using nano-beam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, confirming that the quartz glass is in an amorphous state. However, in the diffraction pattern of an IGZO film deposited at room temperature, a spot-like pattern is observed instead of a halo. Therefore, it is presumed that an IGZO film deposited at room temperature is in an intermediate state, neither crystalline nor amorphous, and cannot be concluded to be in an amorphous state.

[0660] <<Oxide semiconductor structure>> It should be noted that oxide semiconductors may be classified differently from those described above when considering their structure. For example, oxide semiconductors can be divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the aforementioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors also include polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0661] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0662] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, the c-axis of which is oriented in a specific direction. This specific direction is the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region with periodic atomic arrangement. If we consider the atomic arrangement as a lattice arrangement, then a crystalline region is also a region with a aligned lattice arrangement. Furthermore, CAAC-OS has regions where multiple crystalline regions are connected in the ab-plane direction, and these regions may exhibit distortion. Distortion refers to a point in the connected region where the orientation of the lattice arrangement changes between a region with a aligned lattice arrangement and another region with a aligned lattice arrangement. In short, CAAC-OS is an oxide semiconductor that is c-axis oriented and does not exhibit clear orientation in the ab-plane direction.

[0663] Each of the multiple crystalline regions described above is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of a single minute crystal, the maximum diameter of that crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of that crystalline region may be around several tens of nanometers.

[0664] Furthermore, in In-M-Zn oxides (where element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), CAAC-OS tends to have a layered crystalline structure (also called a layered structure) consisting of layers containing indium (In) and oxygen (hereinafter referred to as the In layer) and layers containing element M, zinc (Zn), and oxygen (hereinafter referred to as the (M,Zn) layer). Note that indium and element M are mutually substitutable. Therefore, the (M,Zn) layer may contain indium. Also, the In layer may contain element M. Also, the In layer may contain Zn. This layered structure can be observed, for example, as a lattice image in high-resolution TEM (Transmission Electron Microscope) images.

[0665] When structural analysis of a CAAC-OS film is performed using an XRD instrument, for example, out-of-plane XRD measurements using θ / 2θ scanning show a peak indicating c-axis orientation at 2θ = 31° or nearby. Note that the position of the c-axis orientation peak (value of 2θ) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0666] Furthermore, for example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film. These spots are observed at point-symmetric positions with respect to the incident electron beam spot (also called the direct spot) that passed through the sample.

[0667] When the crystal region is observed from the specific direction described above, the lattice arrangement within that crystal region is based on a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the strain may have lattice arrangements such as pentagons or heptagons. Moreover, in CAAC-OS, clear grain boundaries cannot be observed even near the strain. In other words, it can be seen that the formation of grain boundaries is suppressed by the strain in the lattice arrangement. This is thought to be because CAAC-OS can tolerate strain due to the fact that the arrangement of oxygen atoms is not dense in the ab-plane direction, and the bond distance between atoms changes due to the substitution of metal atoms.

[0668] A crystal structure in which clear grain boundaries are observed is called a polycrystal. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in transistor on-current and field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries are not observed, is one of the crystalline oxides with a suitable crystal structure for the semiconductor layer of a transistor. In addition, a structure containing Zn is preferred for the composition of CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are preferred because they suppress the generation of grain boundaries more than In oxide.

[0669] CAAC-OS is an oxide semiconductor with high crystallinity and no clearly defined grain boundaries. Therefore, CAAC-OS is less susceptible to the decrease in electron mobility caused by grain boundaries. Furthermore, since the crystallinity of oxide semiconductors can decrease due to the inclusion of impurities and the generation of defects, CAAC-OS can be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Consequently, oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat resistant and highly reliable. In addition, CAAC-OS is stable even at high temperatures (so-called thermal budget) during the manufacturing process. Therefore, using CAAC-OS in OS transistors allows for greater flexibility in the manufacturing process.

[0670] [nc-OS] nc-OS exhibits periodicity in atomic arrangement in minute regions (e.g., regions between 1 nm and 10 nm, particularly between 1 nm and 3 nm). In other words, nc-OS contains minute crystals. These minute crystals are also called nanocrystals because their size is, for example, between 1 nm and 10 nm, particularly between 1 nm and 3 nm. Furthermore, nc-OS shows no regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Consequently, depending on the analytical method, nc-OS may be indistinguishable from a-like OS or amorphous oxide semiconductors. For example, when structural analysis of an nc-OS film is performed using an XRD instrument, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Also, when electron diffraction (also called limited-field electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of the nanocrystals (e.g., 50 nm or larger), a diffraction pattern resembling a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystal (for example, 1 nm to 30 nm), an electron diffraction pattern may be obtained in which multiple spots are observed within a ring-shaped region centered on a direct spot.

[0671] [a-like OS] a-like OS is an oxide semiconductor having a structure between nc-OS and amorphous oxide semiconductors. a-like OS has porous or low-density regions. That is, a-like OS has lower crystallinity compared to nc-OS and CAAC-OS. Also, a-like OS has a higher hydrogen concentration in the film compared to nc-OS and CAAC-OS.

[0672] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0673] [CAC-OS] CAC-OS is a material composition in which, for example, the elements constituting the metal oxide are unevenly distributed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size. In the following, a state in which one or more metal elements are unevenly distributed in a metal oxide, and the regions containing these metal elements are mixed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size, is also referred to as a mosaic or patchy state.

[0674] Furthermore, CAC-OS is a composite metal oxide having a mosaic-like structure formed by the separation of the material into a first region and a second region, with the first region distributed within the film (hereinafter also referred to as a cloud-like structure). In other words, CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0675] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting CAC-OS in In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in CAC-OS in In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of CAC-OS. The second region is the region where [Ga] is greater than the [Ga] in the composition of CAC-OS. Alternatively, for example, the first region is the region where [In] is greater than the [In] in the second region, and [Ga] is smaller than the [Ga] in the second region. The second region is the region where [Ga] is greater than the [Ga] in the first region, and [In] is smaller than the [In] in the first region.

[0676] Specifically, the first region described above is a region whose main components are indium oxide, indium zinc oxide, etc. The second region described above is a region whose main components a...

Claims

1. The device comprises a first light-emitting device, a second light-emitting device, a first insulating layer, and a first layer. The first light-emitting device comprises a first pixel electrode, a first light-emitting layer on the first pixel electrode, and a common electrode on the first light-emitting layer. The second light-emitting device comprises a second pixel electrode, a second light-emitting layer on the second pixel electrode, and the common electrode on the second light-emitting layer. The first light-emitting layer covers the side surface of the first pixel electrode, The second light-emitting layer covers the side surface of the second pixel electrode, The first layer is located on the first light-emitting layer, In a cross-sectional view, one end of the first layer is aligned with or approximately aligned with the end of the first light-emitting layer, and the other end of the first layer is located on the first light-emitting layer. The first insulating layer covers the upper surface of the first layer and the respective side surfaces of the first light-emitting layer and the second light-emitting layer. The common electrode is located on the first insulating layer, and is a display device.

2. In claim 1, 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, A display device in which the common layer has at least one 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.

3. In claim 1 or 2, Having a second insulating layer, The first insulating layer has an inorganic material, A display device wherein the second insulating layer has an organic material and overlaps with the respective sides of the first light-emitting layer and the second light-emitting layer via the first insulating layer.

4. The device comprises a first light-emitting device, a second light-emitting device, a first insulating layer, and a first layer. The first light-emitting device comprises a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer. The second light-emitting device comprises a second pixel electrode, a second EL layer on the second pixel electrode, and the common electrode on the second EL layer. The first EL layer comprises a first light-emitting unit on the first pixel electrode, a first charge generation layer on the first light-emitting unit, and a second light-emitting unit on the first charge generation layer. The second EL layer comprises a third light-emitting unit on the second pixel electrode, a second charge generation layer on the third light-emitting unit, and a fourth light-emitting unit on the second charge generation layer. The first EL layer covers the side surface of the first pixel electrode, The second EL layer covers the side surface of the second pixel electrode, The first layer is located on the first EL layer, In a cross-sectional view, one end of the first layer is aligned with or approximately aligned with the end of the first EL layer, and the other end of the first layer is located on the first EL layer. The first insulating layer covers the upper surface of the first layer and the respective side surfaces of the first EL layer and the second EL layer. The common electrode is located on the first insulating layer, and is a display device.

5. In claim 4, 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, A display device in which the common layer has at least one 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.

6. In claim 4 or 5, Having a second insulating layer, The first insulating layer has an inorganic material, A display device wherein the second insulating layer has an organic material and overlaps with the respective sides of the first EL layer and the second EL layer via the first insulating layer.

7. In any one of claims 1 to 6, A display device having a laminated structure in which the first layer comprises an inorganic insulating layer and a conductive layer on the inorganic insulating layer.

8. In any one of claims 1 to 7, The first pixel electrode comprises a first conductive layer and a second conductive layer on the first conductive layer. The second conductive layer covers the side surface of the first conductive layer, and is a display device.

9. A display device according to any one of claims 1 to 8, A display module having at least one of a connector and an integrated circuit.

10. The display module according to claim 9, An electronic device comprising at least one of a housing, a battery, a camera, a speaker, and a microphone.

11. A first pixel electrode and a second pixel electrode are formed on an insulating surface. A first layer is formed on the first pixel electrode and the second pixel electrode. A first sacrificial layer is formed on the first layer described above. The first layer and the first sacrificial layer are processed such that the edges of the first layer and the edges of the first sacrificial layer are located outside the edges of the first pixel electrode, and at least a portion of the second pixel electrode is exposed. A second layer is formed on the first sacrificial layer and the second pixel electrode. A second sacrificial layer is formed on the second layer described above. The second layer and the second sacrificial layer are processed such that the edges of the second layer and the edges of the second sacrificial layer are located outside the edges of the second pixel electrode, and at least a portion of the first sacrificial layer is exposed. A first insulating film is formed covering at least the sides of the first layer, the sides of the second layer, the sides and top of the first sacrificial layer, and the sides and top of the second sacrificial layer. By processing the first insulating film, a first insulating layer is formed such that, in cross-sectional view, one end is located on the first layer and the other end is located on the second layer. The first sacrificial layer is processed such that, in a cross-sectional view, one end aligns with or is approximately aligned with the end of the first layer, and the other end is located on the first layer. A method for manufacturing a display device, comprising forming a common electrode on the first layer and the second layer.

12. In claim 11, Using an inorganic material, the first insulating film is formed. After forming the first insulating film, a second insulating film is formed on the first insulating film using an organic material. A method for manufacturing a display device, comprising processing the second insulating film to form a second insulating layer such that, in a cross-sectional view, one end of the second insulating film is located on the first layer and the other end of the second insulating film is located on the second layer.

13. In claim 12, A method for manufacturing a display device, wherein a photosensitive resin is used as the organic material.

14. In any one of claims 11 to 13, A method for manufacturing a display device, wherein, before forming the common electrode, at least one 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 is formed as a common layer on the first layer and the second layer.

15. In any one of claims 11 to 14, The first pixel electrode comprises a first conductive layer and a second conductive layer on the first conductive layer. The second pixel electrode comprises a third conductive layer and a fourth conductive layer on the third conductive layer. A first conductive film is formed, By processing the first conductive film, the first conductive layer and the third conductive layer are formed. A second conductive film is formed to cover the ends of the first conductive layer and the ends of the third conductive layer. A method for manufacturing a display device, comprising processing the second conductive film to form a second conductive layer covering the edge of the first conductive layer and a fourth conductive layer covering the edge of the third conductive layer.

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