Method for manufacturing a display device

Abstract

The present invention provides a display device that is capable of high-luminance display. A first layer having a first light emitting material that emits blue light is formed in an island shape on a first pixel electrode, after which a second layer having a second light emitting material that emits light of a longer wavelength than blue is formed in an island shape on a second pixel electrode. An insulating layer that overlaps with a region sandwiched by the first pixel electrode and the second pixel electrode is then formed, and a common electrode is formed so as to cover the first layer, the second layer, and the insulating 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) has been developed. A light-emitting device (also referred to as an EL device or an EL element) that utilizes the electroluminescence (hereinafter referred to as EL) phenomenon has characteristics such as being easily thinned and lightened, being able to respond quickly to an input signal, and being 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] One aspect of the present invention is to provide a display device capable of high-brightness display as one of the problems. One aspect of the present invention is to provide a high-definition display device as one of the problems. One aspect of the present invention is to provide a high-resolution display device as one of the problems. One aspect of the present invention is to provide a highly reliable display device as one of the problems.

[0009] One aspect of the present invention is to provide a method for manufacturing a high-definition display device as one of the problems. One aspect of the present invention is to provide a method for manufacturing a high-resolution display device as one of the problems. One aspect of the present invention is to provide a method for manufacturing a highly reliable display device as one of the problems. One aspect of the present invention is to provide a method for manufacturing a display device with a high yield as one of the problems.

[0010] 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]

[0011] One aspect of the present invention involves forming a first pixel electrode and a second pixel electrode, forming a first film on the first pixel electrode and the second pixel electrode, forming a first mask film on the first film, processing the first film and the first mask film to form a first layer and a first mask layer on the first pixel electrode and exposing the second pixel electrode, forming a second film on the first mask layer and the second pixel electrode, forming a second mask film on the second film, processing the second film and the second mask film to form a second layer and a second mask layer on the second pixel electrode and exposing the first mask layer, and the first mask layer and the second mask layer A method for manufacturing a display device, comprising: forming a first insulating film on top; forming a second insulating film on the first insulating film; processing the second insulating film to form a second insulating layer that overlaps with the region sandwiched between the first and second pixel electrodes; using the second insulating layer as a mask to perform an etching process to process the first insulating film, the first mask layer, and the second mask layer to expose the upper surfaces of the first and second layers, and covering the first, second, and second insulating layers to form a common electrode; the first layer having a first light-emitting material that emits blue light, and the second layer having a second light-emitting material that emits light with a longer wavelength than blue.

[0012] One aspect of the present invention involves forming a first pixel electrode and a second pixel electrode, forming a first film on the first pixel electrode and the second pixel electrode, forming a first mask film on the first film, processing the first film and the first mask film to form a first layer and a first mask layer on the first pixel electrode, and exposing the second pixel electrode, forming a second film on the first mask layer and the second pixel electrode, forming a second mask film on the second film, processing the second film and the second mask film to form a second layer and a second mask layer on the second pixel electrode, and exposing the first mask layer, forming a first insulating film on the first mask layer and the second mask layer, forming a second insulating film on the first insulating film, and processing the second insulating film. The method for manufacturing a display device involves forming a second insulating layer that overlaps with the region sandwiched between the first and second pixel electrodes, performing a first etching process using the second insulating layer as a mask to remove a portion of the first insulating film and thin the film thickness of a portion of the first mask layer and a portion of the second mask layer, performing a heat treatment, then performing a second etching process using the second insulating layer as a mask to remove a portion of the first mask layer and a portion of the second mask layer, exposing the upper surfaces of the first and second layers, covering the first layer, the second layer and the second insulating layer to form a common electrode, the first layer having a first light-emitting material that emits blue light, and the second layer having a second light-emitting material that emits light with a longer wavelength than blue.

[0013] One aspect of the present invention involves forming a first pixel electrode, a second pixel electrode, and a first conductive layer; forming a first film on the first pixel electrode and the second pixel electrode; forming a first mask film on the first film and the first conductive layer; processing the first film and the first mask film to form a first layer and a first mask layer on the first pixel electrode; forming a second mask layer on the first conductive layer and exposing the second pixel electrode; forming a second film on the first mask layer and the second pixel electrode; forming a second mask film on the second film; and processing the second film and the second mask film to form a second A second layer and a third mask layer are formed on the pixel electrode, and the first and second mask layers are exposed. A first insulating film is formed on the first to third mask layers. A second insulating film is formed on the first insulating film using a photosensitive resin composition. The second insulating film is exposed and developed to expose the portion of the first insulating film that overlaps with the second mask layer. A first etching process is performed using the second insulating film as a mask to remove the portion of the first insulating film that overlaps with the second mask layer and to thin a portion of the second mask layer. By exposing and developing the second insulating film, the portions of the first insulating film that overlap with the first mask layer and the third mask layer are exposed, forming a second insulating layer that overlaps with the region sandwiched between the first and second pixel electrodes. A second etching process is performed using the second insulating layer as a mask to remove the portions of the first insulating film that overlap with the first mask layer and the third mask layer, forming a first insulating layer that overlaps with the second insulating layer, and thinning the film thickness of a portion of the first mask layer and a portion of the third mask layer, followed by a heat treatment, and then the second A method for manufacturing a display device, comprising: performing a third etching process using the insulating layer 2 as a mask to remove a portion of the first mask layer and a portion of the third mask layer, exposing the upper surfaces of the first layer and the second layer, covering the first layer, the second layer, the first conductive layer, and the second insulating layer to form a common electrode; removing a portion of the second mask layer by a second or third etching process to expose the upper surface of the first conductive layer, wherein the first layer has a first light-emitting material that emits blue light, and the second layer has a second light-emitting material that emits light with a longer wavelength than blue.

[0014] Preferably, the first layer comprises a first light-emitting layer and a first functional layer on the first light-emitting layer, the second layer comprises a second light-emitting layer and a second functional layer on the second light-emitting layer, the first light-emitting layer comprises a first light-emitting material, the second light-emitting layer comprises a second light-emitting material, and the first functional layer and the second functional layer each preferably comprise at least one of a hole injection layer, an electron injection layer, a hole transport layer, an electron transport layer, a hole blocking layer, and an electron blocking layer.

[0015] It is preferable to deposit an aluminum oxide film as the first insulating film using the ALD method, and to deposit aluminum oxide films as the first mask film and the second mask film using the ALD method.

[0016] The second insulating film is preferably formed using a photosensitive acrylic resin.

[0017] The first etching process and the second etching process are preferably carried out by wet etching.

[0018] Furthermore, one aspect of the present invention is a display device manufactured using the above-described method for manufacturing a display device.

[0019] Furthermore, one aspect of the present invention is a display module having a display device manufactured using the above-described method for manufacturing a display device, and which has a connector such as a flexible printed circuit board (FPC) or TCP (Tape Carrier Package) attached to it, or a display module on which an integrated circuit (IC) is mounted by a COG (Chip On Glass) method or COF (Chip On Film) method, etc.

[0020] Furthermore, one aspect of the present invention is an electronic device having the above-mentioned display module and at least one of a housing, a battery, a camera, a speaker, and a microphone. [Effects of the Invention]

[0021] According to one aspect of the present invention, a display device capable of displaying at high brightness can be provided. 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 highly reliable display device can be provided.

[0022] 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 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.

[0023] 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]

[0024] Figure 1A is a top view showing an example of a display device. Figure 1B is a cross-sectional view showing an example of a display device. Figure 1C is a top view showing an example of layer 113R. Figures 2A and 2B are cross-sectional views showing an example of a display device. Figures 3A and 3B are cross-sectional views showing an example of a display device. Figures 4A and 4B are cross-sectional views showing an example of a display device. Figures 5A and 5B are cross-sectional views showing an example of a display device. Figures 6A and 6B are cross-sectional views showing an example of a display device. Figure 7A is a cross-sectional view showing an example of a display device. Figures 7B and 7C are cross-sectional views showing an example of a pixel electrode. Figures 8A to 8C are cross-sectional views showing an example of a display device. Figures 9A and 9B are cross-sectional views showing an example of a display device. Figures 10A to 10C are cross-sectional views showing an example of a display device. Figures 11A and 11B are cross-sectional views showing an example of a display device. Figure 12A is a top view showing an example of a display device. Figure 12B is a cross-sectional view showing an example of 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. Figures 16A to 16C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 17A to 17C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 18A to 18F are cross-sectional views showing an example of a method for manufacturing a display device. Figures 19A to 19C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 20A and 20B are cross-sectional views showing an example of a method for manufacturing a display device. Figures 21A to 21G show examples of pixels. Figures 22A to 22K show examples of pixels. Figures 23A and 23B are perspective views showing an example of a display device. Figures 24A to 24C are cross-sectional views showing an example of a display device. Figure 25 is a cross-sectional view 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. Figure 28 is a cross-sectional view showing an example of a display device. Figure 29 is a cross-sectional view showing an example of a display device. Figure 30 is a perspective view showing an example of a display device. Figure 31A is a cross-sectional view showing an example of a display device. Figures 31B and 31C are cross-sectional views showing an example of a transistor. Figures 32A to 32D are cross-sectional views showing an example of a display device. Figure 33 is a cross-sectional view showing an example of a display device. Figures 34A to 34F show examples of the configuration of a light-emitting device. Figures 35A and 35B show examples of the configuration of a light receiving device. Figures 35C to 35E show examples of the configuration of a display device. Figures 36A to 36D show examples of electronic devices. Figures 37A to 37F show examples of electronic devices. Figures 38A to 38G show examples of electronic devices. Figures 39A to 39D are photographs of the light-emitting display device of Example 1. Figures 40A to 40D are photographs of the light emission of the display device of Example 1. Figure 41 shows the blue index-luminance characteristics of the light-emitting device of Example 2. Figure 42 shows the emission spectrum of the light-emitting device of Example 2. Figure 43 shows the brightness-current density characteristics of the light-emitting device of Example 2. Figure 44 shows the current density-voltage characteristics of the light-emitting device of Example 2. Figure 45 shows the current efficiency-luminance characteristics of the light-emitting device of Example 2. Figure 46 shows the emission spectrum of the light-emitting device of Example 2. Figure 47 shows the brightness-current density characteristics of the light-emitting device of Example 2. Figure 48 shows the current density-voltage characteristics of the light-emitting device of Example 2. Figure 49 shows the current efficiency-luminance characteristics of the light-emitting device of Example 2. Figure 50 shows the emission spectrum of the light-emitting device of Example 2. Figure 51 shows the brightness-current density characteristics of the light-emitting device of Example 2. Figure 52 shows the current density-voltage characteristics of the light-emitting device of Example 2. Figure 53 shows the results of the reliability test of the light-emitting device in Example 2. Figure 54 shows the results of the reliability test of the light-emitting device in Example 2. Figure 55 shows the results of the reliability test of the light-emitting device in Example 2. Figure 56 shows the results of the reliability test of the light-emitting device in Example 2. Figure 57 shows the CIE1931 chromaticity coordinates of the display device of Example 3. Figure 58A shows the method for measuring the chromaticity of the display device in Example 3. Figure 58B is a diagram illustrating the viewing angle dependence of the chromaticity of the display device in Example 3. Figure 59 shows the results of the reliability test of the light-emitting device in Example 4. Figure 60 shows the results of the reliability test of the light-emitting device in Example 4. Figure 61 shows the results of the reliability test of the light-emitting device in Example 4. Figure 62 shows the results of the reliability test of the light-emitting device in Example 4. Figure 63 shows the results of the reliability test of the light-emitting device in Example 4. Figure 64 shows the results of the reliability test of the light-emitting device in Example 4. Figures 65A to 65F are photographs of the pixels of the display device of Example 4. Figure 66A is an SEM observation image showing the pixels of the display device of Example 5. Figure 66B is a schematic cross-sectional view of the display device of Example 5. Figures 67A to 67D are photographs of the light emission of the display device of Example 6. Figure 68 shows the CIE1931 chromaticity coordinates of the display device of Example 6. Figure 69 shows the measurement results of the emission spectrum of the display device of Example 6. [Modes for carrying out the invention]

[0025] 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.

[0026] 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.

[0027] Furthermore, for the sake of ease of understanding, the position, size, and scope of each component shown in the drawings may not represent their actual position, size, and scope. Therefore, the disclosed invention is not necessarily limited to the position, size, and scope disclosed in the drawings.

[0028] 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."

[0029] 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.

[0030] In this specification, a structure in which at least the light-emitting layers are created separately for light-emitting devices with different emission wavelengths may be referred to as an SBS (Side By Side) structure. Because the SBS structure allows for the optimization of materials and configuration for each light-emitting device, it increases the freedom of material and configuration selection, making it easier to improve brightness and reliability.

[0031] In this specification, holes or electrons may be referred to as "carriers." Specifically, a hole injection layer or electron injection layer may be called a "carrier injection layer," a hole transport layer or electron transport layer may be called a "carrier transport layer," and a hole block layer or electron block layer may be called a "carrier block layer." Note that the above-mentioned carrier injection layer, carrier transport layer, and carrier block layer may not be clearly distinguishable by their cross-sectional shape or characteristics. Furthermore, a single layer may combine the functions of two or three of these carrier injection, carrier transport, and carrier block layers.

[0032] In this specification, a light-emitting device (also called a light-emitting element) has an EL layer between a pair of electrodes. The EL layer has at least a light-emitting layer. Examples of the layers (also called functional layers) of 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 blocking layer (hole blocking layer and electron blocking layer).

[0033] In this specification, a photodetector (also called a photodetector) has an active layer that functions as at least a photoelectric conversion layer between a pair of electrodes.

[0034] In this specification, "island-like" refers to a state in which two or more layers made of the same material and formed in the same process are physically separated. For example, an island-like light-emitting layer refers to a state in which the light-emitting layer and an adjacent light-emitting layer are physically separated.

[0035] In this specification, a tapered shape refers to a shape in which at least a portion of the side surface of a structure is inclined with respect to the substrate surface or the surface to be formed. For example, it is preferable to have a region in which the angle (also called the taper angle) between the inclined side surface and the substrate surface or the surface to be formed is less than 90°. The side surface of the structure, the surface to be formed, and the substrate surface do not necessarily have to be perfectly flat, and may be substantially planar with fine curvature, or substantially planar with fine irregularities.

[0036] In this specification, the mask layer is located at least above the light-emitting layer (more specifically, the layer that is processed into an island shape among the layers constituting the EL layer) and has the function of protecting the light-emitting layer during the manufacturing process.

[0037] (Embodiment 1) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 1 to 12.

[0038] A display device according to one aspect of the present invention has light-emitting devices that are manufactured separately for each light-emitting color, and is capable of full-color display.

[0039] When manufacturing a display device that has multiple light-emitting devices, each with a different light-emitting color, it is necessary to form each light-emitting layer with a different light-emitting color in an island-like structure.

[0040] For example, island-shaped light-emitting layers can be formed using a vacuum deposition method with a metal mask. However, with this method, deviations from the design occur in the shape and position of the island-shaped light-emitting layers due to various factors such as the precision of the metal mask, misalignment between the metal mask and the substrate, deflection of the metal mask, and the spreading of the contour of the deposited film due to vapor scattering, making it difficult to achieve high resolution and high aperture ratio in display devices. In addition, the contour of the layer may become blurred during deposition, and the thickness at the edges may become thinner. In other words, the thickness of the island-shaped light-emitting layer formed using a metal mask may vary depending on the location. Furthermore, when manufacturing large, high-resolution, or high-definition display devices, there is a concern that the low dimensional accuracy of the metal mask and deformation due to heat, etc., may lead to low manufacturing yield.

[0041] Therefore, when manufacturing a display device according to one aspect of the present invention, the light-emitting layer is processed into a fine pattern by photolithography without using a shadow mask such as a metal mask. Specifically, after forming a pixel electrode for each sub-pixel, a light-emitting layer is deposited across multiple pixel electrodes. Subsequently, the light-emitting layer is processed using photolithography to form one island-shaped light-emitting layer for each pixel electrode. This divides the light-emitting layer for each sub-pixel, allowing for the formation of an island-shaped light-emitting layer for each sub-pixel.

[0042] For example, if a display device consists of three types of light-emitting devices—a blue light-emitting device (also simply called a blue light-emitting device), a green light-emitting device (also simply called a green light-emitting device), and a red light-emitting device (also simply called a red light-emitting device)—then three types of island-shaped light-emitting layers can be formed by repeating the deposition of the light-emitting layer and processing by photolithography three times.

[0043] In this context, the state of the interface between the pixel electrode and the EL layer is important for the characteristics of the light-emitting device. In the process of forming the island-shaped light-emitting layer described above, the pixel electrodes of the light-emitting devices of the second and subsequent colors formed may be damaged by the preceding process. As a result, the driving voltage of the light-emitting devices of the second and subsequent colors may increase.

[0044] Furthermore, light-emitting devices that emit shorter wavelengths (i.e., higher energy) light require higher drive voltages, so blue light-emitting devices tend to have higher drive voltages than red or green light-emitting devices. Also, blue light-emitting devices tend to be less reliable compared to other colors.

[0045] Therefore, when manufacturing a display device according to one aspect of the present invention, it is preferable to start by depositing the light-emitting layer of the light-emitting device that emits the shortest wavelength light, for example, a blue light-emitting device. For example, it is preferable to deposit the light-emitting layers in the order of blue, green, red, or blue, red, green.

[0046] This allows for maintaining good interface conditions between the pixel electrodes and the EL layer in blue light-emitting devices, thereby suppressing an increase in the driving voltage of the blue light-emitting devices. Furthermore, it extends the lifespan of the blue light-emitting devices and improves their reliability. Since red and green light-emitting devices are less affected by increases in driving voltage compared to blue light-emitting devices, the overall driving voltage of the display device can be lowered, resulting in higher reliability.

[0047] When processing the above-mentioned light-emitting layer into an island shape, a structure in which the processing is performed using photolithography directly above the light-emitting layer is conceivable. In this structure, the light-emitting layer may be damaged (e.g., damage from processing), and its reliability may be significantly impaired. Therefore, when manufacturing a display device according to one aspect of the present invention, it is preferable to use a method in which a mask layer (also called a sacrificial layer, protective layer, etc.) is formed on a functional layer located above the light-emitting layer (for example, a carrier block layer, carrier transport layer, or carrier injection layer, more specifically a hole block layer, electron transport layer, or electron injection layer, etc.), and the light-emitting layer and the functional layer are processed into an island shape. By applying this method, a highly reliable display device can be provided. By having another functional layer between the light-emitting layer and the mask layer, it is possible to suppress the exposure of the light-emitting layer to the outermost surface during the manufacturing process of the display device and reduce the damage the light-emitting layer receives.

[0048] Preferably, the EL layer has a first region which is the light-emitting region (also called the light-emitting area) and a second region outside the first region. The second region can also be called a dummy region or dummy area. The first region is located between the pixel electrode and the common electrode. During the manufacturing process of the display device, the first region is covered by a mask layer, and the damage it receives is extremely reduced. Therefore, a light-emitting device with high luminous efficiency and a long lifespan can be realized. On the other hand, the second region includes the edge of the EL layer and its vicinity, and includes parts that may be damaged during the manufacturing process of the display device, such as by exposure to plasma. By not using the second region as the light-emitting region, variations in the characteristics of the light-emitting device can be suppressed.

[0049] Furthermore, when processing the above-mentioned light-emitting layer into an island shape, it is preferable to process the layer located below the light-emitting layer (for example, a carrier injection layer, a carrier transport layer, or a carrier block layer, more specifically a hole injection layer, a hole transport layer, or an electron block layer) into an island shape with the same pattern as the light-emitting layer. By processing the layer located below the light-emitting layer into an island shape with the same pattern as the light-emitting layer, it is possible to reduce the leakage current (sometimes called lateral leakage current, transverse leakage current, or lateral leakage current) that may occur between adjacent subpixels. For example, when a hole injection layer is used in common between adjacent subpixels, a transverse leakage current may occur due to the hole injection layer. On the other hand, in a display device according to one aspect of the present invention, since the light-emitting layer and the hole injection layer can be processed into the same island shape, a transverse leakage current between adjacent subpixels can be substantially eliminated or made extremely small.

[0050] For example, when processing using photolithography, the EL layer may suffer various types of damage due to heating during the preparation of the resist mask, and exposure to etching solution or etching gas during processing and removal of the resist mask. Furthermore, when a mask layer is placed on the EL layer, the EL layer may also be affected by heating, etching solution, etching gas, etc., during the deposition, processing, and removal of the mask layer.

[0051] Furthermore, if the subsequent processes after the deposition of the EL layer are carried out at temperatures higher than the heat resistance temperature of the EL layer, the EL layer may degrade, potentially reducing the luminous efficiency and reliability of the light-emitting device.

[0052] Therefore, in one embodiment of the present invention, the heat resistance temperature of the compounds contained in the light-emitting device is preferably 100°C or more and 180°C or less, more preferably 120°C or more and 180°C or less, and even more preferably 140°C or more and 180°C or less.

[0053] Indicators of heat resistance temperature include, for example, the glass transition temperature (Tg), softening point, melting point, thermal decomposition temperature, and 5% weight loss temperature. For example, the glass transition temperature of the material in each layer constituting the EL layer can be used as an indicator of the heat resistance temperature of that layer. In the case of a mixed layer consisting of multiple materials, for example, the glass transition temperature of the most abundant material can be used. Alternatively, the lowest temperature among the glass transition temperatures of the multiple materials may be used.

[0054] In particular, it is preferable to increase the heat resistance temperature of the functional layer provided on the light-emitting layer. Furthermore, it is even more preferable to increase the heat resistance temperature of the functional layer provided in contact with the light-emitting layer. The high heat resistance of the functional layer makes it possible to effectively protect the light-emitting layer and reduce the damage it receives.

[0055] Furthermore, it is particularly preferable to increase the heat resistance temperature of the light-emitting layer. This helps to prevent damage to the light-emitting layer due to heating, which can reduce luminous efficiency and shorten the lifespan of the material.

[0056] By increasing the heat resistance temperature of light-emitting devices, their reliability can be improved. Furthermore, the temperature range in the manufacturing process of display devices can be broadened, leading to improved manufacturing yield and reliability.

[0057] 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. 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 mask layer is removed, and the remaining layers constituting the EL layer (sometimes called a common 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.

[0058] On the other hand, the carrier injection layer is often a relatively conductive layer within the EL layer. Therefore, there is a risk of short-circuiting the light-emitting device if the carrier injection layer comes into contact with the side surface of some of the island-shaped EL layers or the side surface of the pixel electrode. Furthermore, even when the carrier injection layer is provided in an island shape and a common electrode is formed in common for each color light-emitting device, there is a risk of short-circuiting the light-emitting device if the common electrode comes into contact with the side surface of the EL layer or the side surface of the pixel electrode.

[0059] Therefore, a display device according to one aspect of the present invention has an insulating layer that covers at least the sides of the island-shaped light-emitting layer. Furthermore, it is preferable that the insulating layer covers a portion of the upper surface of the island-shaped light-emitting layer.

[0060] 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.

[0061] In a cross-sectional view, it is preferable that the edges of the insulating layer have a tapered shape with a taper angle of less than 90°. This prevents step breaks in the common layer and common electrode provided on the insulating layer. Therefore, connection failures due to step breaks can be suppressed. In addition, it is possible to suppress the local thinning of the common electrode due to the step, which would increase electrical resistance.

[0062] 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).

[0063] Thus, the island-shaped light-emitting layer produced by the method for manufacturing a display device according to one aspect of the present invention is not formed using a fine metal mask, but rather by processing after the light-emitting 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 light-emitting layer can be made 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 mask layer on the light-emitting layer, the damage that the light-emitting layer receives during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0064] Furthermore, while it is difficult to reduce the spacing between adjacent light-emitting devices to less than 10 μm using, for example, a formation method employing a fine metal mask, according to one embodiment of the present invention, in a process on a glass substrate, the spacing between adjacent light-emitting devices, adjacent EL layers, or adjacent pixel electrodes can be narrowed to less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, 1.5 μm or less, 1 μm or less, or 0.5 μm or less. Moreover, by using, for example, an exposure apparatus for LSIs, in a process on a Si Wafer, the spacing between adjacent light-emitting devices, adjacent EL layers, or adjacent pixel electrodes can be narrowed to, for example, 500 nm or less, 200 nm or less, 100 nm or less, and even 50 nm or less. This significantly reduces the area of ​​the non-emitting region that may exist between two light-emitting devices, making it possible to bring the aperture ratio closer to 100%. For example, in a display device according to one aspect of the present invention, the aperture ratio can be 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, and even 90% or more, while achieving less than 100%.

[0065] Furthermore, increasing the aperture ratio of a display device can improve its reliability. More specifically, using an organic EL device, if the lifespan of a display device with an aperture ratio of 10% is used as a baseline, the lifespan of a display device with an aperture ratio of 20% (i.e., twice the aperture ratio of the baseline) is approximately 3.25 times longer, and the lifespan of a display device with an aperture ratio of 40% (i.e., four times the aperture ratio of the baseline) is approximately 10.6 times longer. Thus, as the aperture ratio is increased, the current density flowing through the organic EL device required to obtain the same display can be reduced, making it possible to improve the lifespan of the display device. In one embodiment of the present invention, since the aperture ratio can be increased, the display quality of the display device can be improved. Moreover, as the aperture ratio of the display device is increased, the reliability (especially the lifespan) of the display device is significantly improved, which is a great effect.

[0066] Furthermore, the pattern of the light-emitting layer itself (which can also be called the processing size) can be made extremely small compared to when using a fine metal mask. Also, for example, when a metal mask is used to create different types of light-emitting layers, variations in thickness occur between the center and edges of the light-emitting layer, so the effective area that can be used as a light-emitting region is small relative to the area of ​​the light-emitting layer. On the other hand, with the above manufacturing method, since a film deposited to a uniform thickness is processed, island-shaped light-emitting layers can be formed with a uniform thickness. Therefore, even with a fine pattern, almost the entire area can be used as a light-emitting region. As a result, it is possible to manufacture a display device that combines high resolution and a high aperture ratio. In addition, it is possible to achieve miniaturization and weight reduction of the display device.

[0067] Specifically, the resolution of the display device according to one embodiment of the present invention is, for example, 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and can be 20000 ppi or less, or 30000 ppi or less.

[0068] In this embodiment, the cross-sectional structure of the display device according to one aspect of the present invention will be mainly described, and the method for manufacturing the display device according to one aspect of the present invention will be described in detail in Embodiment 2.

[0069] Figure 1A shows a top view of the display device 100. The display device 100 has a display unit on which a plurality of pixels 110 are arranged, and a connection unit 140 outside the display unit. Multiple subpixels are arranged in a matrix on the display unit. In Figure 1A, two rows and six columns of subpixels are shown, and these constitute a two-row, two-column pixel 110. The connection unit 140 can also be called the cathode contact unit.

[0070] The top surface shape of the subpixel shown in Figure 1A corresponds to the top surface shape of the light-emitting region. In this specification, the top surface shape of a component refers to the contour shape of that component in a plan view (also referred to as a top view). A plan view refers to viewing from the direction normal to the surface on which the component is formed, or the surface of the support (e.g., substrate) on which the component is formed.

[0071] The top surface shape of the subpixel may include, for example, polygons such as triangles, quadrilaterals (including rectangles and squares), pentagons, polygons with rounded corners, ellipses, or circles.

[0072] 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, the transistors in subpixel 11R may be located within the range of subpixel 11G shown in Figure 1A, or some or all of them may be located outside the range of subpixel 11R.

[0073] In Figure 1A, the aperture ratios (sizes, also known as the size of the light-emitting area) of the sub-pixels 11R, 11G, and 11B 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 11R, 11G, and 11B can be determined as appropriate. The aperture ratios of the sub-pixels 11R, 11G, and 11B may be different, or two or more may be equal or approximately equal.

[0074] A stripe array is applied to pixel 110 shown in Figure 1A. Pixel 110 in Figure 1A is composed of three subpixels: subpixel 11R, subpixel 11G, and subpixel 11B. Each of the subpixels 11R, 11G, and 11B has a light-emitting device that emits light of a different color. Examples of subpixels 11R, 11G, and 11B include subpixels of three colors: red (R), green (G), and blue (B); and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). Furthermore, the number of subpixel types is not limited to three; there may be four or more. Examples of four subpixels include subpixels of four colors: R, G, B, and white (W); subpixels of four colors: R, G, B, and Y; and subpixels of four colors: R, G, B, and infrared (IR).

[0075] In this specification, the row direction is sometimes referred to as the X direction, and the column direction as the Y direction. The X and Y directions intersect, for example, perpendicularly (see Figure 1A). 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.

[0076] Figure 1A shows an example where the connecting portion 140 is located below the display portion in a top view, but the position of the connecting portion 140 is not particularly limited. The connecting 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. The top shape of the connecting portion 140 can be a strip, L-shape, U-shape, or frame shape, etc. Also, there may be one or more connecting portions 140.

[0077] Figure 1B shows a cross-sectional view between the dashed-dotted lines X1 and X2 in Figure 1A. Figure 1C shows a top view of layer 113R. Figures 2A and 2B show enlarged views of parts of the cross-sectional view shown in Figure 1B. Figures 3 to 6 show modified examples of Figure 2. Figures 7A and 8 to 10 show modified examples of Figure 1B. Figures 7B and 7C show cross-sectional views of modified pixel electrodes. Figures 11A and 11B show a cross-sectional view between the dashed-dotted lines Y1 and Y2 in Figure 1A.

[0078] As shown in Figure 1B, the display device 100 has an insulating layer on a layer 101 containing transistors, light-emitting devices 130R, 130G, and 130B on the insulating layer, and a protective layer 131 covering these light-emitting devices. The 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.

[0079] In Figure 1B, multiple cross-sections of the insulating layer 125 and insulating layer 127 are shown, but when the display device 100 is viewed from above, the insulating layer 125 and insulating layer 127 are connected as one unit each. In other words, the display device 100 can be configured to have, for example, one insulating layer 125 and one insulating layer 127. The display device 100 may also have multiple insulating layers 125 that are separated from each other, or multiple insulating layers 127 that are separated from each other.

[0080] 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.

[0081] The layer 101 containing the transistors can, for example, be a laminated structure in which multiple transistors are provided on a substrate and insulating layers are provided to cover these transistors. The insulating layers on the transistors may be a single layer or a laminated structure. Figure 1B shows insulating layer 255a, insulating layer 255b on insulating layer 255a, and insulating layer 255c on insulating layer 255b, which are insulating layers on the transistors. These insulating layers may have recesses between adjacent light-emitting devices. Figure 1B and others show an example in which insulating layer 255c has a recess. Note that insulating layer 255c does not have to have a recess between adjacent light-emitting devices. The insulating layers on the transistors (insulating layers 255a to insulating layers 255c) may also be considered as part of the layer 101 containing the transistors.

[0082] 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, 255b, and 255c, respectively. For insulating layers 255a and 255c, it is preferable to use oxide insulating films or oxidative nitride insulating films such as silicon oxide films, silicon oxidative nitride films, and aluminum oxide films, respectively. For insulating layer 255b, it is preferable to use nitride insulating films or nitride-oxide insulating films such as silicon nitride films and silicon nitride-oxide films. More specifically, it is preferable to use silicon oxide films as insulating layers 255a and 255c, and silicon nitride films as insulating layer 255b. It is preferable that insulating layer 255b has the function of an etching protective film.

[0083] In this specification, "oxide nitride" refers to a material in which the oxygen content is greater than the nitrogen content, and "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.

[0084] An example of the configuration of layer 101 including the transistor will be described later in Embodiment 4.

[0085] Light-emitting device 130R emits red (R) light, light-emitting device 130G emits green (G) light, and light-emitting device 130B emits blue (B) light.

[0086] As the light-emitting device, it is preferable to use, for example, an OLED (Organic Light Emitting Diode) or a QLED (Quantum-dot Light Emitting Diode). Examples of light-emitting materials for the light-emitting device include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence (TADF) materials, and inorganic compounds (quantum dot materials, etc.). In addition, LEDs such as microLEDs (Light Emitting Diodes) can also be used as the light-emitting device.

[0087] The light-emitting device can emit light in the following colors: infrared, red, green, blue, cyan, magenta, yellow, or white. Furthermore, the color purity can be improved by adding a microcavity structure to the light-emitting device.

[0088] For the configuration and materials of the light-emitting device, refer to Embodiment 5.

[0089] In a light-emitting device, one electrode functions as the anode and the other as the cathode. In the following explanation, we may use the example where the pixel electrode functions as the anode and the common electrode functions as the cathode.

[0090] The light-emitting device 130R includes a pixel electrode 111R on an insulating layer 255c, an island-shaped layer 113R on the pixel electrode 111R, a common layer 114 on the island-shaped layer 113R, and a common electrode 115 on the common layer 114. In the light-emitting device 130R, the layer 113R and the common layer 114 can be collectively referred to as the EL layer.

[0091] The light-emitting device 130G includes a pixel electrode 111G on an insulating layer 255c, an island-shaped layer 113G on the pixel electrode 111G, a common layer 114 on the island-shaped layer 113G, and a common electrode 115 on the common layer 114. In the light-emitting device 130G, the layer 113G and the common layer 114 can be collectively referred to as the EL layer.

[0092] The light-emitting device 130B includes a pixel electrode 111B on an insulating layer 255c, an island-shaped layer 113B on the pixel electrode 111B, a common layer 114 on the island-shaped layer 113B, and a common electrode 115 on the common layer 114. In the light-emitting device 130B, the layer 113B and the common layer 114 can be collectively referred to as the EL layer.

[0093] In this specification, among the EL layers of a light-emitting device, layers provided in an island-like manner for each light-emitting device are referred to as layer 113B, layer 113G, or layer 113R, and layers shared by multiple light-emitting devices are referred to as common layer 114. In this specification, layers 113R, 113G, and 113B may be referred to as island-like EL layers, island-shaped EL layers, etc., without including the common layer 114.

[0094] Layers 113R, 113G, and 113B are separated from each other. By providing the EL layers in an island-like configuration for each light-emitting device, leakage current between adjacent light-emitting devices can be suppressed. This prevents crosstalk caused by unintended light emission, enabling the realization of a display device with extremely high contrast. In particular, it enables the realization of a display device with high current efficiency at low brightness levels.

[0095] It is preferable that the ends of each of the pixel electrodes 111R, 111G, and 111B have a tapered shape. Specifically, it is preferable that the ends of each of the pixel electrodes 111R, 111G, and 111B have a tapered shape with a taper angle of less than 90°. When the ends of these pixel electrodes have a tapered shape, the layers 113R, 113G, and 113B provided along the sides of the pixel electrodes have inclined portions. By making the sides of the pixel electrodes tapered, the coverage of the EL layer provided along the sides of the pixel electrodes can be improved.

[0096] Furthermore, while Figure 1B and other figures illustrate a configuration in which the angle between the side wall of the recess provided in the insulating layer 255c and the insulating layer 255b has a taper angle equivalent to that of the taper shape of the pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B, the configuration is not limited to this. For example, the taper shape of the pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B may be different from the taper shape of the recess formed in the insulating layer 255c.

[0097] In Figure 1B, there is no insulating layer (also called a partition, bank, or spacer) covering the upper edge of the pixel electrode 111R between the pixel electrode 111R and layer 113R. Similarly, there is no insulating layer covering the upper edge of the pixel electrode 111G between the pixel electrode 111G and layer 113G. As a result, the spacing between adjacent light-emitting devices can be made extremely narrow. Consequently, a high-definition or high-resolution display device can be produced. Furthermore, a mask for forming the insulating layer becomes unnecessary, reducing the manufacturing cost of the display device.

[0098] Furthermore, by not providing an insulating layer covering the edges of the pixel electrodes between the pixel electrodes and the EL layer, in other words, by not providing an insulating layer between the pixel electrodes and the EL layer, the light emitted from the EL layer can be efficiently extracted. Therefore, a display device according to one aspect of the present invention can have extremely low viewing angle dependence. By reducing viewing angle dependence, the visibility of images in the display device can be improved. For example, in a display device according to one aspect of the present invention, the viewing angle (the maximum angle at which a constant contrast ratio is maintained when viewing the screen from an oblique direction) can be set to a range of 100° or more and less than 180°, preferably 150° or more and 170° or less. The above viewing angle can be applied to both vertical and horizontal directions.

[0099] The light-emitting device of this embodiment may be a single structure (a structure having only one light-emitting unit) or a tandem structure (a structure having multiple light-emitting units). The light-emitting unit has at least one light-emitting layer.

[0100] Layers 113R, 113G, and 113B each have at least an emissive layer. Layer 113R has an emissive layer that emits red light, layer 113G has an emissive layer that emits green light, and layer 113B has an emissive layer that emits blue light. In other words, layer 113R has an emissive material that emits red light, layer 113G has an emissive material that emits green light, and layer 113B has an emissive material that emits blue light.

[0101] Furthermore, when using a tandem light-emitting device, it is preferable that layer 113R has a structure having multiple light-emitting units that emit red light, layer 113G has a structure having multiple light-emitting units that emit green light, and layer 113B has a structure having multiple light-emitting units that emit blue light. It is preferable to provide a charge generation layer between each light-emitting unit.

[0102] Furthermore, layers 113R, 113G, and 113B may each have one or more of the following: a hole injection layer, a hole transport layer, a hole blocking layer, a charge generation layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0103] For example, layers 113R, 113G, and 113B may each have a hole injection layer, a hole transport layer, an emissive layer, and an electron transport layer in that order. An electron blocking layer may also be present between the hole transport layer and the emissive layer. Furthermore, a hole blocking layer may be present between the electron transport layer and the emissive layer. Additionally, an electron injection layer may be present on the electron transport layer.

[0104] Furthermore, for example, layers 113R, 113G, and 113B may each have an electron injection layer, an electron transport layer, an emissive layer, and a hole transport layer in that order. A hole blocking layer may also be present between the electron transport layer and the emissive layer. An electron blocking layer may also be present between the hole transport layer and the emissive layer. A hole injection layer may also be present on the hole transport layer.

[0105] Thus, it is preferable that each of layers 113R, 113G, and 113B has an emissive layer and a carrier transport layer (electron transport layer or hole transport layer) on the emissive layer. Alternatively, it is preferable that each of layers 113R, 113G, and 113B has an emissive layer and a carrier block layer (hole block layer or electron block layer) on the emissive layer. Alternatively, it is preferable that each of layers 113R, 113G, and 113B has an emissive layer, a carrier block layer on the emissive layer, and a carrier transport layer on the carrier block layer. Since the surfaces of layers 113R, 113G, and 113B are exposed during the manufacturing process of the display device, by providing one or both of the carrier transport layer and the carrier block layer on the emissive layer, it is possible to suppress the exposure of the emissive layer to the outermost surface and reduce the damage to the emissive layer. This can improve the reliability of the light-emitting device.

[0106] The heat resistance temperature of the compounds contained in layers 113R, 113G, and 113B is preferably 100°C to 180°C, more preferably 120°C to 180°C, and even more preferably 140°C to 180°C. For example, the glass transition temperature (Tg) of these compounds is preferably 100°C to 180°C, more preferably 120°C to 180°C, and even more preferably 140°C to 180°C.

[0107] In particular, it is preferable that the heat resistance temperature of the functional layer provided on the light-emitting layer is high. Furthermore, it is even more preferable that the heat resistance temperature of the functional layer provided in contact with the light-emitting layer is high. The high heat resistance of the functional layer makes it possible to effectively protect the light-emitting layer and reduce the damage it receives.

[0108] Furthermore, it is preferable that the heat resistance temperature of the light-emitting layer be high. This helps to prevent damage to the light-emitting layer due to heating, which can reduce luminous efficiency and shorten its lifespan.

[0109] The light-emitting layer comprises a light-emitting substance (also called a light-emitting material, light-emitting organic compound, guest material, etc.) and an organic compound (also called a host material, etc.). Because the light-emitting layer contains a larger proportion of the organic compound compared to the light-emitting substance, the Tg of the organic compound can be used as an indicator of the heat resistance temperature of the light-emitting layer.

[0110] Furthermore, layers 113R, 113G, and 113B may each have, for example, a first light-emitting unit, a charge-generating layer on the first light-emitting unit, and a second light-emitting unit on the charge-generating layer.

[0111] The second light-emitting unit preferably has a light-emitting layer and a carrier transport layer (electron transport layer or hole transport layer) on the light-emitting layer. Alternatively, the second light-emitting unit preferably has a light-emitting layer and a carrier block layer (hole block layer or electron block layer) on the light-emitting layer. Alternatively, the second light-emitting unit preferably has a light-emitting layer, a carrier block layer on the light-emitting layer, and a carrier transport layer on the carrier block layer. Since the surface of the second light-emitting unit is exposed during the manufacturing process of the display device, by providing one or both of the carrier transport layer and the carrier block layer on the light-emitting layer, it is possible to suppress the exposure of the light-emitting layer to the outermost surface and reduce the damage to the light-emitting layer. This can improve the reliability of the light-emitting device. If there are three or more light-emitting units, it is preferable that the light-emitting unit provided in the uppermost layer has a light-emitting layer and one or both of the carrier transport layer and the carrier block layer on the light-emitting layer.

[0112] The common layer 114 may have, for example, an electron injection layer or a hole injection layer. Alternatively, the common layer 114 may have an electron transport layer and an electron injection layer stacked together, or a hole transport layer and a hole injection layer stacked together. The common layer 114 is shared by the light-emitting devices 130R, 130G, and 130B.

[0113] Figure 1B shows an example where the edge of layer 113R is located outside the edge of pixel electrode 111R. Although the explanation uses pixel electrode 111R and layer 113R as examples, the same applies to pixel electrode 111G and layer 113G, and pixel electrode 111B and layer 113B.

[0114] In Figure 1B, layer 113R is formed to cover the edge of the pixel electrode 111R. This configuration makes it possible to make the entire upper surface of the pixel electrode an emissive region, and it is easier to increase the aperture ratio compared to a configuration in which the edge of the island-shaped EL layer is located inside the edge of the pixel electrode.

[0115] Furthermore, by covering the sides of the pixel electrodes with the EL layer, contact between the pixel electrodes and the common electrode 115 can be suppressed, thereby preventing short circuits in the light-emitting device. In addition, the distance between the light-emitting region of the EL layer (i.e., the region overlapping with the pixel electrodes) and the edge of the EL layer can be increased. Since the edge of the EL layer may be damaged during processing, using a region away from the edge of the EL layer as the light-emitting region can sometimes improve the reliability of the light-emitting device.

[0116] Preferably, layers 113R, 113G, and 113B each have a first region which is a light-emitting region and a second region (dummy region) outside the first region. The first region is located between the pixel electrode and the common electrode. The first region is covered by the mask layer during the manufacturing process of the display device, and the damage it receives is extremely reduced. Therefore, a light-emitting device with high luminous efficiency and a long lifespan can be realized. On the other hand, the second region includes the edge of the EL layer and its vicinity, and includes parts that may be damaged during the manufacturing process of the display device, such as by exposure to plasma. By not using the second region as a light-emitting region, variations in the characteristics of the light-emitting device can be suppressed.

[0117] The width L3 shown in Figures 1B and 1C corresponds to the width of the first region 113_1 (luminescent region) in layer 113R. The widths L1 and L2 shown in Figures 1B and 1C correspond to the width of the second region 113_2 (dummy region) in layer 113R. As shown in Figure 1C, the second region 113_2 is provided so as to surround the first region 113_1; therefore, in cross-sectional views such as Figure 1B, the width of the second region 113_2 can be confirmed at two locations, left and right. The width of the second region 113_2 can be either width L1 or width L2; for example, it may be the shorter of widths L1 and L2. Widths L1 to L3 can be confirmed in cross-sectional observation images. Note that in Figure 1C, widths L1 to L3 are shown as widths in the X direction, but widths L1 to L3 may also be widths in the Y direction.

[0118] The enlarged view shown in Figure 2A shows the width L2 of the second region 113_2. The second region 113_2 is the portion in layer 113R where at least one of the mask layer 118R, insulating layer 125, and insulating layer 127 overlap. Also, as shown in region 103 in Figure 5B, the portion in layer 113R, etc., that is located outside the edge of the upper surface of the pixel electrode is a dummy region.

[0119] The width of the second region 113_2 is 1 nm or more, preferably 5 nm or more, 50 nm or more, or 100 nm or more. A wider dummy region is preferable because it allows for more uniform quality of the light-emitting region and suppresses variations in the characteristics of the light-emitting device. On the other hand, a narrower dummy region allows for a wider light-emitting region and increases the aperture ratio of the pixels. Therefore, the width of the second region 113_2 is preferably 50% or less of the width L3 of the first region 113_1, more preferably 40% or less, 30% or less, 20% or less, or 10% or less. Furthermore, in the case of small and high-resolution display devices such as those for wearable devices, the width of the second region 113_2 is preferably 500 nm or less, more preferably 300 nm or less, 200 nm or less, or 150 nm or less.

[0120] In the island-shaped EL layer, the first region (emission region) is the region where EL (electroluminescence) emission is obtained. Furthermore, in the island-shaped EL layer, both the first region (emission region) and the second region (dummy region) are regions where PL (photoluminescence) emission is obtained. Therefore, it can be said that the first region and the second region can be distinguished by confirming EL emission and PL emission.

[0121] Furthermore, the common electrode 115 is shared by the light-emitting devices 130R, 130G, and 130B. The common electrode 115, which is shared by multiple light-emitting devices, is electrically connected to the conductive layer 123 provided in the connection portion 140 (see Figures 11A and 11B). It is preferable to use a conductive layer for the conductive layer 123 that is made of the same material and formed using the same process as the pixel electrodes 111R, 111G, and 111B.

[0122] In Figure 11A, a common layer 114 is provided on the conductive layer 123, and the conductive layer 123 and the common electrode 115 are electrically connected via the common layer 114. The common layer 114 does not necessarily have to be provided at the connection part 140. In Figure 11B, the conductive layer 123 and the common electrode 115 are directly connected. For example, by using a mask to define 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 deposited by the common layer 114 and the common electrode 115 can be changed.

[0123] Furthermore, in Figure 1B, a mask layer 118R is located on layer 113R of the light-emitting device 130R, a mask layer 118G is located on layer 113G of the light-emitting device 130G, and a mask layer 118B is located on layer 113B of the light-emitting device 130B. The mask layer is provided so as to surround the first region 113_1 (light-emitting region). In other words, the mask layer has an opening in the portion that overlaps with the light-emitting region. The upper surface shape of the mask layer is consistent, roughly consistent, or similar to the second region 113_2 shown in Figure 1C. Mask layer 118B is a portion of the mask layer that remained after being provided in contact with the upper surface of layer 113B when layer 113B was processed. Similarly, mask layer 118G is a portion of the mask layer that remained after being provided when layer 113G was formed, and mask layer 118R is a portion of the mask layer that remained after being provided when layer 113R was formed. Thus, in one embodiment of the present invention, the display device may have a portion of the mask layer used to protect the EL layer during its manufacture remaining. Two or all of the mask layers 118R, 118G, and 118B may be made of the same material, or different materials may be used. In the following, the mask layers 118R, 118G, and 118B may be collectively referred to as the mask layer 118.

[0124] In Figure 1B, one end of the mask layer 118R (the end opposite to the light-emitting region, the outer end) is aligned with or approximately aligned with the end of layer 113R, and the other end of the mask layer 118R is located on layer 113R. Here, it is preferable that the other end of the mask layer 118R (the end on the light-emitting region side, the inner end) overlaps with layer 113R and the pixel electrode 111R. In this case, the other end of the mask layer 118R is more likely to be formed on the flat or approximately flat surface of layer 113R. The same applies to mask layers 118G and 118B. Furthermore, the mask layer 118 remains between the upper surface of the island-shaped EL layer (layer 113R, layer 113G, or layer 113B) and the insulating layer 125. The mask layer will be described in detail in Embodiment 2.

[0125] 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.

[0126] Each side of layer 113R, layer 113G, and layer 113B is covered by the insulating layer 125. The insulating layer 127 overlaps (or covers) each side of layer 113R, layer 113G, and layer 113B via the insulating layer 125.

[0127] Furthermore, portions of the upper surfaces of layers 113R, 113G, and 113B are covered by the mask layer 118. The insulating layers 125 and 127 overlap portions of the upper surfaces of layers 113R, 113G, and 113B via the mask layer 118. Note that the upper surfaces of layers 113R, 113G, and 113B are not limited to the upper surfaces of the flat portions that overlap with the upper surfaces of the pixel electrodes, but may also include the upper surfaces of the inclined portions and flat portions (see region 103 in Figure 5A) located outside the upper surfaces of the pixel electrodes.

[0128] By covering a portion of the upper surface and sides of layers 113R, 113G, and 113B with at least one of the insulating layer 125, insulating layer 127, and mask layer 118, the common layer 114 (or common electrode 115) is prevented from coming into contact with the pixel electrodes 111R, 111G, 111B, and the sides of layers 113R, 113G, and 113B, thereby suppressing a short circuit in the light-emitting device. This improves the reliability of the light-emitting device.

[0129] In Figure 1B, the film thicknesses of layers 113R, 113G, and 113B are all shown to be the same, but the present invention is not limited to this. The film thicknesses of layers 113R, 113G, and 113B may be different. For example, it is preferable to set the film thickness to correspond to the optical path length that intensifies the light emitted by each of layers 113R, 113G, and 113B. This makes it possible to realize a microcavity structure and improve the color purity in each light-emitting device.

[0130] The insulating layer 125 is preferably in contact with the respective sides of layers 113R, 113G, and 113B (see the dashed lines at the edges of layers 113R and 113G and their vicinity in Figure 2A). By configuring the insulating layer 125 to be in contact with layers 113R, 113G, and 113B, delamination of layers 113R, 113G, and 113B can be prevented. The close contact between the insulating layer and layers 113B, 113G, or 113R provides the effect of fixing or bonding adjacent layers 113B, etc., to the insulating layer 125. Furthermore, the contact between the insulating layer 125 and the insulating layer 255c is also effective in preventing delamination of layers 113R, 113G, and 113B. This can improve the reliability of the light-emitting device and increase the manufacturing yield of the light-emitting device.

[0131] Furthermore, as shown in Figure 1B, the insulating layers 125 and 127 cover both a portion of the upper surface and the sides of layers 113R, 113G, and 113B, thereby further preventing delamination of the EL layer and improving the reliability of the light-emitting device. Additionally, the manufacturing yield of the light-emitting device can be increased.

[0132] Figure 1B shows an example where a stacked structure of layer 113R, mask layer 118R, insulating layer 125, and insulating layer 127 is located on the edge of pixel electrode 111R. Similarly, a stacked structure of layer 113G, mask layer 118G, insulating layer 125, and insulating layer 127 is located on the edge of pixel electrode 111G, and a stacked structure of layer 113B, mask layer 118B, insulating layer 125, and insulating layer 127 is located on the edge of pixel electrode 111B.

[0133] Figure 1B shows a configuration in which the edge of the pixel electrode 111R is covered by layer 113R, and the insulating layer 125 is in contact with the side surface of layer 113R. Similarly, the edge of the pixel electrode 111G is covered by layer 113G, the edge of the pixel electrode 111B is covered by layer 113B, and the insulating layer 125 is in contact with the side surfaces of layer 113G and layer 113B.

[0134] The insulating layer 127 is provided on the insulating layer 125 so as to fill the recesses of the insulating layer 125. The insulating layer 127 can be configured to overlap a portion of the upper surface and side surfaces of layers 113R, 113G, and 113B, respectively, via the insulating layer 125. Preferably, the insulating layer 127 covers at least a portion of the side surfaces of the insulating layer 125.

[0135] By providing insulating layers 125 and 127, the gaps between adjacent island-shaped layers can be filled, thereby reducing the large height differences and irregularities on the surface of layers formed on the island-shaped layers (e.g., carrier injection layers and common electrodes), making them flatter. Consequently, the coverage of the carrier injection layers and common electrodes can be improved.

[0136] The common layer 114 and common electrode 115 are provided on layers 113R, 113G, 113B, mask layer 118, insulating layer 125, and insulating layer 127. Before the insulating layers 125 and 127 are provided, a step difference occurs due to the region where the pixel electrode and island-shaped EL layer are provided and the region where the pixel electrode and island-shaped EL layer are not provided (the region between light-emitting devices). In one embodiment of the present invention, the presence of insulating layers 125 and 127 can flatten this step difference and improve the coverage of the common layer 114 and common electrode 115. Therefore, connection failures due to step breaks can be suppressed. In addition, it is possible to suppress the local thinning of the common electrode 115 due to the step difference, which would increase its electrical resistance.

[0137] The upper surface of the insulating layer 127 preferably has a shape that is highly flat, but it may also have convex portions, convex curved surfaces, concave curved surfaces, or recesses. For example, the upper surface of the insulating layer 127 preferably has a highly flat, smooth convex curved surface shape.

[0138] Next, we will describe examples of materials for the insulating layer 125 and the insulating layer 127.

[0139] 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 film and aluminum nitride 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 an inorganic insulating film such as an aluminum oxide film, a hafnium oxide film, or a silicon oxide film formed by atomic layer deposition (ALD) to the insulating layer 125, an insulating layer 125 with fewer pinholes and excellent protection for the EL layer can be formed. Alternatively, the insulating layer 125 may have a laminated structure of a film formed by ALD and a film formed by sputtering. For example, the insulating layer 125 may have a laminated structure of an aluminum oxide film formed by ALD and a silicon nitride film formed by sputtering.

[0140] Preferably, the insulating layer 125 functions as a barrier insulating layer against at least one of water and oxygen. Furthermore, preferably, the insulating layer 125 has the function of suppressing the diffusion of at least one of water and oxygen. Also, preferably, the insulating layer 125 has the function of capturing or fixing (also known as gettering) at least one of water and oxygen.

[0141] In this specification, the term "barrier insulating layer" refers to an insulating layer that has barrier properties. Furthermore, in this specification, "barrier properties" refers to a function that suppresses the diffusion of the corresponding substance (also known as low permeability), or a function that captures or fixes the corresponding substance (also known as gettering).

[0142] The insulating layer 125 has the function of a barrier insulating layer or a gettering function, thereby suppressing the intrusion of impurities (typically at least one of water and oxygen) that could diffuse from the outside into each light-emitting device. This configuration makes it possible to provide a highly reliable light-emitting device, and furthermore, a highly reliable display device.

[0143] Furthermore, it is preferable that the insulating layer 125 has a low impurity concentration. This prevents impurities from mixing from the insulating layer 125 into the EL layer and degrading the EL layer. Also, by lowering the impurity concentration in the insulating layer 125, the barrier properties against at least one of water and oxygen can be improved. For example, it is desirable that the insulating layer 125 has a sufficiently low hydrogen concentration and a sufficiently low carbon concentration, preferably both.

[0144] Furthermore, the same material can be used for the insulating layer 125 and the mask layers 118B, 118G, and 118R. In this case, the boundary between any of the mask layers 118B, 118G, and 118R and the insulating layer 125 may become unclear and indistinguishable. Therefore, the mask layer 118B, 118G, and 118R and the insulating layer 125 may be identified as a single layer. In other words, one layer may be observed to be in contact with a portion of the upper surface and side surface of each of the layers 113R, 113G, and 113B, with the insulating layer 127 covering at least a portion of the side surface of that single layer.

[0145] The insulating layer 127, provided on the insulating layer 125, has the function of flattening the large height differences and irregularities 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 forming the common electrode 115.

[0146] As the insulating layer 127, an insulating layer having an organic material can be suitably used. Preferably, a photosensitive organic resin is used as the organic material; for example, a photosensitive resin composition containing an acrylic resin is preferred. In this specification, the term "acrylic resin" does not refer only to polymethacrylate esters or methacrylic resins, but may refer to acrylic polymers in a broad sense.

[0147] Furthermore, as the insulating layer 127, 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 may be used. Alternatively, as the insulating layer 127, 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. Additionally, a photoresist may be used as the photosensitive resin. Either a positive-type or negative-type material may be used as the photosensitive organic resin.

[0148] The insulating layer 127 may be made of a material that absorbs visible light. By absorbing the light emitted from the light-emitting device, the insulating layer 127 can suppress light leakage (stray light) from the light-emitting device to adjacent light-emitting devices through the insulating layer 127. This improves the display quality of the display device. Furthermore, since the display quality can be improved without using a polarizing plate in the display device, the display device can be made lighter and thinner.

[0149] Examples of materials that absorb visible light include materials containing pigments such as black, materials containing dyes, light-absorbing resin materials (e.g., polyimide), and resin materials that can be used as color filters (color filter materials). In particular, it is preferable to use a resin material which is made by laminating or mixing two or more color filter materials, as this can enhance the visible light shielding effect. In particular, by mixing three or more color filter materials, it is possible to create a black or near-black resin layer.

[0150] Next, the structure of the insulating layer 127 and its vicinity will be described using Figures 2A and 2B. Figure 2A is an enlarged cross-sectional view of the region including the insulating layer 127 and its surroundings between light-emitting devices 130R and 130G. In the following explanation, the insulating layer 127 between light-emitting devices 130R and 130G will be used as an example, but the same applies to the insulating layer 127 between light-emitting devices 130G and 130B, and the insulating layer 127 between light-emitting devices 130B and 130R, etc. Figure 2B is an enlarged view of the edge of the insulating layer 127 on layer 113G and its vicinity, as shown in Figure 2A. In the following explanation, the edge of the insulating layer 127 on layer 113G will be used as an example, but the same applies to the edge of the insulating layer 127 on layer 113B, and the edge of the insulating layer 127 on layer 113R, etc.

[0151] As shown in Figure 2A, layer 113R is provided covering pixel electrode 111R, and layer 113G is provided covering pixel electrode 111G. Mask layer 118R is provided in contact with a part of the upper surface of layer 113R, and mask layer 118G is provided in contact with a part of the upper surface of layer 113G. Insulating layer 125 is provided in contact with the upper and side surfaces of mask layer 118R, the side surfaces of layer 113R, the upper surface of insulating layer 255c, the upper and side surfaces of mask layer 118G, and the side surfaces of layer 113G. Insulating layer 125 also covers a part of the upper surface of layer 113R and a part of the upper surface of layer 113G. Insulating layer 127 is provided in contact with the upper surface of insulating layer 125. Furthermore, the insulating layer 127 overlaps with a portion of the upper surface and side surface of layer 113R, and a portion of the upper surface and side surface of layer 113G, via the insulating layer 125, and is in contact with at least a portion of the side surface of the insulating layer 125. A common layer 114 is provided covering layer 113R, mask layer 118R, layer 113G, mask layer 118G, insulating layer 125, and insulating layer 127, and a common electrode 115 is provided on the common layer 114.

[0152] Furthermore, the insulating layer 127 is formed in the region between the two island-shaped EL layers (for example, in Figure 2A, the region between layer 113R and layer 113G). At this time, at least a portion of the insulating layer 127 is positioned between the side edge of one EL layer (for example, layer 113R in Figure 2A) and the side edge of the other EL layer (for example, layer 113G in Figure 2A). By providing such an insulating layer 127, it is possible to prevent the formation of divided areas and locally thin areas in the common layer 114 and common electrode 115 formed on the island-shaped EL layers and the insulating layer 127.

[0153] As shown in Figure 2B, the insulating layer 127 preferably has a tapered shape with a taper angle θ1 at its end in a cross-sectional view of the display device. The taper angle θ1 is the angle between the side surface of the insulating layer 127 and the substrate surface. However, it is not limited to the substrate surface; it may also be the angle between the upper surface of the flat portion of layer 113G, or the upper surface of the flat portion of the pixel electrode 111G, and the side surface of the insulating layer 127.

[0154] The taper angle θ1 of the insulating layer 127 is less than 90°, preferably 60° or less, more preferably 45° or less, and even more preferably 20° or less. By making the edges of the insulating layer 127 have such a forward taper shape, the common layer 114 and common electrode 115 provided on the insulating layer 127 can be formed with good coverage, and the occurrence of step breaks or localized thinning can be suppressed. As a result, the in-plane uniformity of the common layer 114 and common electrode 115 can be improved, and the display quality of the display device can be improved.

[0155] Furthermore, as shown in Figure 2A, in a cross-sectional view of the display device, it is preferable that the upper surface of the insulating layer 127 has a convex curved shape. It is preferable that the convex curved shape of the upper surface of the insulating layer 127 is a shape that bulges gently towards the center. It is also preferable that the convex curved portion in the central part of the upper surface of the insulating layer 127 is continuously connected to the tapered portion at the end. By making the insulating layer 127 such a shape, the common layer 114 and the common electrode 115 can be formed on the entire insulating layer 127 with good coverage.

[0156] As shown in Figure 2B, it is preferable that the edge of the insulating layer 127 is located outside the edge of the insulating layer 125. This reduces the surface irregularities forming the common layer 114 and the common electrode 115, thereby improving the coverage of the common layer 114 and the common electrode 115.

[0157] As shown in Figure 2B, the insulating layer 125 preferably has a tapered shape with a taper angle θ2 at its end in a cross-sectional view of the display device. The taper angle θ2 is the angle between the side surface of the insulating layer 125 and the substrate surface. However, it is not limited to the substrate surface; it may also be the angle between the upper surface of the flat portion of layer 113G, or the upper surface of the flat portion of the pixel electrode 111G, and the side surface of the insulating layer 125.

[0158] The taper angle θ2 of the insulating layer 125 is less than 90°, preferably 60° or less, more preferably 45° or less, and even more preferably 20° or less.

[0159] The mask layer 118G preferably has a tapered shape with a taper angle θ3 at its end in a cross-sectional view of the display device, as shown in Figure 2B. The taper angle θ3 is the angle between the side surface of the mask layer 118G and the substrate surface. However, it is not limited to the substrate surface; it may also be the angle between the upper surface of the flat portion of layer 113G, or the upper surface of the flat portion of the pixel electrode 111G, and the side surface of the insulating layer 127.

[0160] The taper angle θ3 of the mask layer 118G is less than 90°, preferably 60° or less, more preferably 45° or less, and even more preferably 20° or less. By giving the mask layer 118G such a forward taper shape, the common layer 114 and the common electrode 115 provided on the mask layer 118G can be formed with good coverage.

[0161] It is preferable that the edges of mask layer 118B and mask layer 118G are located outside the edges of the insulating layer 125. This reduces the surface irregularities forming the common layer 114 and common electrode 115, thereby improving the coverage of the common layer 114 and common electrode 115.

[0162] As will be detailed in Embodiment 2, if the etching process of the insulating layer 125 and the mask layer 118 is performed at the same time, side etching may cause the insulating layer 125 and the mask layer 118 below the edge of the insulating layer 127 to disappear, forming a cavity (which can also be called a hole). This cavity can cause unevenness on the surface forming the common layer 114 and the common electrode 115, making it easier for the common layer 114 and the common electrode 115 to break down. Therefore, by performing the etching process in two stages and performing a heat treatment between the two etching stages, even if a cavity is formed in the first etching stage, the insulating layer 127 can be deformed by the heat treatment and the cavity can be filled. In addition, since the second etching stage involves etching a thin film, the amount of side etching is reduced, making it less likely for a cavity to form, and even if a cavity is formed, it can be made extremely small. Therefore, it is possible to suppress the occurrence of unevenness on the surface forming the common layer 114 and the common electrode 115, and to suppress the breaking down of the common layer 114 and the common electrode 115. Because the etching process is performed twice, the taper angles θ2 and θ3 may be different angles. Alternatively, taper angles θ2 and θ3 may be the same angle. Furthermore, taper angles θ2 and θ3 may each be smaller than taper angle θ1.

[0163] The insulating layer 127 may cover at least a portion of the side surface of the mask layer 118R and at least a portion of the side surface of the mask layer 118G. For example, Figure 2B shows an example where the insulating layer 127 in contact with and covers the inclined surface located at the edge of the mask layer 118G formed by the first etching process, while the inclined surface located at the edge of the mask layer 118G formed by the second etching process is exposed. These two inclined surfaces can sometimes be distinguished by their different taper angles. Alternatively, there may be little difference in the taper angles of the side surfaces formed by the two etching processes, making them indistinguishable.

[0164] Furthermore, Figures 3A and 3B show examples in which the insulating layer 127 covers the entire side surface of the mask layer 118R and the entire side surface of the mask layer 118G. Specifically, in Figure 3B, the insulating layer 127 covers both of the two inclined surfaces in contact with each other. This is preferable because it can further reduce the unevenness of the surfaces forming the common layer 114 and the common electrode 115. Figure 3B shows an example in which the edge of the insulating layer 127 is located outside the edge of the mask layer 118G. The edge of the insulating layer 127 may be located inside the edge of the mask layer 118G, as shown in Figure 2B, and may be aligned with or approximately aligned with the edge of the mask layer 118G. Also, as shown in Figure 3B, the insulating layer 127 may be in contact with layer 113G.

[0165] In Figure 3B, it is preferable that the taper angles θ1 to θ3 are within the above ranges.

[0166] Furthermore, Figures 4A and 4B show examples in which the insulating layer 127 has a concave curved shape (also called a constricted portion, recess, indentation, or depression) on its side surface. Depending on the material of the insulating layer 127 and the formation conditions (heating temperature, heating time, and heating atmosphere, etc.), a concave curved shape may be formed on the side surface of the insulating layer 127.

[0167] Figure 4A shows an example where the insulating layer 127 covers a portion of the side surface of the mask layer 118G, leaving the rest of the side surface of the mask layer 118G exposed. Figure 4B shows an example where the insulating layer 127 is in contact with and covers the entire side surface of the mask layer 118R and the entire side surface of the mask layer 118G.

[0168] Furthermore, as shown in Figures 2 to 4, it is preferable that one end of the insulating layer 127 overlaps with the upper surface of the pixel electrode 111R, and the other end of the insulating layer 127 overlaps with the upper surface of the pixel electrode 111G. With this structure, the end of the insulating layer 127 can be formed on a flat or substantially flat region of layers 113R and 113G. Therefore, it becomes relatively easy to form the tapered shapes of the insulating layer 127, insulating layer 125, and mask layer 118. In addition, peeling of the film of the pixel electrodes 111R, 111G, layer 113R, and layer 113G can be suppressed. On the other hand, the smaller the overlap portion between the upper surface of the pixel electrode and the insulating layer 127, the wider the light-emitting region of the light-emitting device becomes, and the higher the aperture ratio can be, which is preferable.

[0169] Note that the insulating layer 127 does not have to overlap with the upper surface of the pixel electrode. As shown in Figure 5A, the insulating layer 127 may not overlap with the upper surface of the pixel electrode, with one end of the insulating layer 127 overlapping with the side surface of the pixel electrode 111R and the other end of the insulating layer 127 overlapping with the side surface of the pixel electrode 111G. Also, as shown in Figure 5B, the insulating layer 127 may not overlap with the pixel electrode and may be provided in the region sandwiched between the pixel electrode 111R and the pixel electrode 111G. In Figures 5A and 5B, part or all of the upper surface of the inclined portion and flat portion (region 103) located outside the upper surface of the pixel electrode of the upper surfaces of layers 113R and 113G are covered by the mask layer 118, the insulating layer 125, and the insulating layer 127. Even with this configuration, compared to a configuration without the mask layer 118, insulating layer 125, and insulating layer 127, the surface irregularities forming the common layer 114 and common electrode 115 can be reduced, and the coverage of the common layer 114 and common electrode 115 can be improved. Region 103 can be called a dummy region.

[0170] Furthermore, as shown in Figure 6A, the upper surface of the insulating layer 127 may have a flat portion in a cross-sectional view of the display device.

[0171] Furthermore, as shown in Figure 6B, the upper surface of the insulating layer 127 may have a concave curved shape in a cross-sectional view of the display device. In Figure 6B, the upper surface of the insulating layer 127 has a shape that bulges gently towards the center, that is, a convex curved surface, and a shape that is concave in the center and its vicinity, that is, a concave curved surface. Also in Figure 6B, the convex curved portion of the upper surface of the insulating layer 127 is continuously connected to the tapered portion at the end. Even if the insulating layer 127 has such a shape, the common layer 114 and the common electrode 115 can be formed on the entire insulating layer 127 with good coverage.

[0172] To create a configuration in which the insulating layer 127 has a concave curved surface in the center, as shown in Figure 6B, an exposure method using a multi-tone mask (typically a halftone mask or graytone mask) can be applied. A multi-tone mask is an exposure mask that allows exposure at three exposure levels: an exposed area, an intermediate exposed area, and an unexposed area, resulting in transmitted light of multiple intensities. With a single photomask (a single exposure and development process), it is possible to form an insulating layer 127 having multiple (typically two) thicknesses.

[0173] The method for forming a concave curved surface in the central part of the insulating layer 127 is not limited to the above. For example, two photomasks may be used to create an exposed portion and an intermediate exposed portion separately. Alternatively, the viscosity of the resin material used for the insulating layer 127 may be adjusted. Specifically, the viscosity of the material used for the insulating layer 127 may be set to 10 cP or less, preferably 1 cP or more and 5 cP or less.

[0174] Although not shown in the figures, the concave curved surface in the center of the insulating layer 127 does not necessarily have to be continuous and may be interrupted between adjacent light-emitting devices. In this case, as shown in Figure 6B, a portion of the insulating layer 127 disappears in the center, and the surface of the insulating layer 125 is exposed. In this configuration, the shape should be such that the common layer 114 and the common electrode 115 can be covered.

[0175] As described above, in each configuration shown in Figures 2 to 6, by providing insulating layer 127, insulating layer 125, mask layer 118R, and mask layer 118G, the common layer 114 and common electrode 115 can be formed with high coverage from the flat or approximately flat region of layer 113R to the flat or approximately flat region of layer 113G. This prevents the formation of divided areas in the common layer 114 and common electrode 115, as well as areas with locally thin film thickness. Therefore, it is possible to suppress connection failures caused by divided areas and increases in electrical resistance caused by locally thin film thickness in the common layer 114 and common electrode 115 between each light-emitting device. As a result, the display device according to one aspect of the present invention can improve display quality.

[0176] It is preferable to have a protective layer 131 on the light-emitting devices 130R, 130G, and 130B. 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.

[0177] The conductivity of the protective layer 131 is not required. The protective layer 131 can be at least one of an insulating film, a semiconductor film, and a conductive film.

[0178] The presence of an inorganic film in the protective layer 131 prevents oxidation of the common electrode 115, suppresses the intrusion of impurities (such as moisture and oxygen) into the light-emitting device, thereby suppressing degradation of the light-emitting device and improving the reliability of the display device.

[0179] For the protective layer 131, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidoxide-nitriding insulating films, and nitride-oxide insulating films can be used. Specific examples of these inorganic insulating films are given in the description of the insulating layer 125. In particular, the protective layer 131 preferably has a nitride insulating film or a nitride-oxide insulating film, and more preferably has a nitride insulating film.

[0180] Furthermore, the protective layer 131 may also be an inorganic film containing In-Sn oxide (also known as ITO), In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or indium gallium zinc oxide (In-Ga-Zn oxide, also known as IGZO). The inorganic film is preferably highly resistive, and more specifically, it is preferably more resistive than the common electrode 115. The inorganic film may further contain nitrogen.

[0181] 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.

[0182] 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.

[0183] 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. Examples of organic materials that can be used for the protective layer 131 include organic insulating materials that can be used for the insulating layer 127.

[0184] 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.

[0185] A light-shielding layer may be provided on the side 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-gathering films. Furthermore, surface protection layers such as an antistatic film to suppress dust adhesion, a water-repellent film to prevent dirt from adhering, a hard coat film to suppress scratches during use, and an impact-absorbing layer may be placed on the outside of the substrate 120. For example, a glass layer or a silica layer (SiO₂) may be used as the surface protection layer. x By providing a protective layer, surface contamination and scratching can be suppressed, which is preferable. Furthermore, as a surface protective layer, DLC (diamond-like carbon), aluminum oxide (AlO2) x ), polyester-based materials, or polycarbonate-based materials may be used. It is preferable to use a material with high transmittance to visible light for the surface protective layer. Furthermore, it is preferable to use a material with high hardness for the surface protective layer.

[0186] The substrate 120 can be made of glass, quartz, ceramics, 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.

[0187] 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.

[0188] 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).

[0189] 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.

[0190] 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.

[0191] Furthermore, when a film is used as the substrate, the film may absorb water, potentially causing wrinkles or other shape changes in the display device. Therefore, it is preferable to use a film with a low water absorption rate as 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.

[0192] 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.

[0193] 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, for example, 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.

[0194] 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 counter electrodes) in light-emitting devices.

[0195] 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.

[0196] Figure 7A shows a modified version of Figure 1B. In Figure 7A, the top and side surfaces of pixel electrodes 111R, 111G, and 111B are covered by conductive layers 116R, 116G, and 116B, respectively. Conductive layers 116R, 116G, and 116B can also be considered as part of the pixel electrodes.

[0197] In Figure 1B, the side surface of the pixel electrode 111R is in contact with layer 113R. If the pixel electrode 111R has a stacked structure, there will be multiple conductive layers in contact with layer 113R. This may result in areas where the adhesion between the pixel electrode 111R and layer 113R is low. The same applies between the pixel electrode 111G and layer 113G, and between the pixel electrode 111B and layer 113B.

[0198] Furthermore, if a portion of the film that will become the conductive layers 116R, 116G, and 116B is removed by wet etching after the formation of the pixel electrodes 111R, 111G, and 111B, galvanic corrosion may occur if the etching solution comes into contact with the pixel electrodes 111R, 111G, and 111B.

[0199] Figure 7A shows that the top and side surfaces of the pixel electrodes 111R, 111G, and 111B are covered by conductive layers 116R, 116G, and 116B, respectively. This prevents the etching solution from coming into contact with the pixel electrodes 111R, 111G, and 111B, thus suppressing deterioration due to galvanic corrosion and other factors. This expands the range of material choices for the pixel electrode 111R. Furthermore, since layer 113R and the conductive layer 116R are in contact, the adhesion is also uniform.

[0200] In the case of a top-emission type display device, it is preferable to use electrodes that are reflective to visible light (reflective electrodes) for the pixel electrodes 111R, 111G, and 111B, and electrodes that are transparent to visible light (transparent electrodes) for the conductive layers 116R, 116G, and 116B.

[0201] The pixel electrode 111 shown in Figure 7B has a three-layer structure, and the conductive layer 116 has a single-layer structure. For example, it is preferable to use a three-layer structure of a titanium film, an aluminum film, and a titanium film as the pixel electrode 111, and to use an oxide conductive layer (for example, In-Si-Sn oxide (also called ITSO)) as the conductive layer 116. The aluminum film has high reflectivity and is suitable as a reflective electrode. On the other hand, if aluminum and the oxide conductive layer come into contact, there is a risk of galvanic corrosion. Therefore, it is preferable to provide a titanium film between the aluminum film and the oxide conductive layer.

[0202] The pixel electrode 111 shown in Figure 7C has a three-layer structure, and the conductive layer 116 has a two-layer structure. For example, it is preferable to use a three-layer structure of a titanium film, an aluminum film, and a titanium film as the pixel electrode 111, and a two-layer structure of a titanium film and an oxide conductive layer (e.g., ITSO) as the conductive layer 116.

[0203] As shown in Figures 8A to 8C, the display device may be provided with a lens array 133. The lens array 133 can be mounted on top of the light-emitting device.

[0204] Figures 8A and 8B show an example in which a lens array 133 is provided on light-emitting devices 130R, 130G, and 130B via a protective layer 131. By directly forming the lens array 133 on the substrate on which the light-emitting devices are formed, the alignment accuracy between the light-emitting devices and the lens array can be improved.

[0205] Figure 8C shows an example in which a substrate 120 on which a lens array 133 is provided is bonded to a protective layer 131 by a resin layer 122. By providing the lens array 133 on the substrate 120, the temperature of the heat treatment in these formation processes can be increased.

[0206] Figure 8B shows an example in which a layer with planarization function is used as the protective layer 131, but as shown in Figures 8A and 8C, the protective layer 131 does not have to have a planarization function. For example, by using an organic film for the protective layer 131, the upper surface of the protective layer 131 can be made flat. Also, the protective layer 131 shown in Figures 8A and 8C can be formed by using, for example, an inorganic film.

[0207] The lens array 133 may have its convex surface facing the substrate 120 side, or it may face the light-emitting device side.

[0208] The lens array 133 can be formed using at least one of an inorganic material and an organic material. For example, a material containing resin can be used for the lens. Alternatively, a material containing at least one of an oxide and a sulfide can be used for the lens. As the lens array 133, for example, a microlens array can be used. The lens array 133 may be formed directly on a substrate or on a light-emitting device, or a separately formed lens array may be bonded to it.

[0209] As shown in Figures 9A and 9B, a colored layer may be provided in the display device. For example, a colored layer 132R that transmits red light can be layered with a red light-emitting device 130R, a colored layer 132G that transmits green light can be layered with a green light-emitting device 130G, and a colored layer 132B that transmits blue light can be layered with a blue light-emitting device 130B. For example, unwanted wavelengths of light emitted from the red light-emitting device 130R can be blocked using the colored layer 132R that transmits red light. With such a configuration, the color purity of the light emitted from each light-emitting device can be further increased. Although the above description refers to a red light-emitting device, the same effect can be achieved with combinations of a green light-emitting device 130G and a colored layer 132G, and with a blue light-emitting device 130B and a colored layer 132B.

[0210] By layering a colored layer with the light-emitting device, external light reflection can be significantly reduced, which is preferable. Furthermore, if the light-emitting device has a microcavity structure, external light reflection can be further reduced. Thus, by applying one or both of the colored layer and / or microcavity structure, external light reflection can be sufficiently suppressed without using optical components such as circular polarizers in the display device. By not using circular polarizers in the display device, attenuation of light emission from the light-emitting device can be suppressed, and the light extraction efficiency of the light-emitting device can be increased. As a result, the power consumption of the display device can be reduced.

[0211] Furthermore, it is preferable that the colored layers of different colors overlap. The overlapping regions of the colored layers can function as a light-shielding layer. This further reduces external light reflection.

[0212] Figure 9A shows an example in which colored layers 132R, 132G, and 132B are provided on light-emitting devices 130R, 130G, and 130B via a protective layer 131. By directly forming the colored layers 132R, 132G, and 132B on the substrate on which the light-emitting devices are formed, the accuracy of the alignment between the light-emitting devices and the colored layers can be improved. Furthermore, by bringing the positions of the light-emitting devices and the colored layers closer together, it is possible to suppress color mixing and improve viewing angle characteristics, which is preferable.

[0213] As shown in Figure 9A, the colored layer is preferably provided on a protective layer 131 having a planarization function. By forming the colored layer on a highly flat surface, it is possible to suppress the formation of irregularities on the colored layer that depend on the surface to be formed on. This suppresses the diffuse reflection of some of the light emitted by the light-emitting device due to irregularities in the colored layer, thereby improving the display quality of the display device. For example, the protective layer 131 preferably has an inorganic insulating film on the common electrode 115 and an organic insulating film on the inorganic insulating film.

[0214] Figure 9B shows an example in which a substrate 120, provided with colored layers 132R, 132G, and 132B, is bonded to a protective layer 131 by a resin layer 122. By providing the colored layers 132R, 132G, and 132B on the substrate 120, the temperature of the heat treatment in the formation process can be increased.

[0215] As shown in Figures 10A to 10C, the display device may be provided with both a colored layer and a lens array.

[0216] Figure 10A shows an example in which colored layers 132R, 132G, and 132B are provided on light-emitting devices 130R, 130G, and 130B via a protective layer 131, an insulating layer 134 is provided on the colored layers 132R, 132G, and 132B, and a lens array 133 is provided on the insulating layer 134. By directly forming the colored layers 132R, 132G, 132B, and the lens array 133 on the substrate on which the light-emitting devices are formed, the accuracy of the alignment between the light-emitting devices and the colored layers or lens arrays can be improved.

[0217] The insulating layer 134 can be an inorganic insulating film, an organic insulating film, or both. The insulating layer 134 may be a single-layer structure or a multi-layer structure. For example, the insulating layer 134 can be made from a material that can be used for the protective layer 131. Since the light emitted from the light-emitting device is extracted through the insulating layer 134, it is preferable that the insulating layer 134 has high transmittance to visible light.

[0218] In Figure 10A, the light emitted from the light-emitting device passes through the colored layer, then through the lens array 133, and is extracted to the outside of the display device. Bringing the light-emitting device and the colored layer closer together is preferable because it can suppress color mixing and improve viewing angle characteristics. Alternatively, the lens array 133 may be provided on the light-emitting device, and the colored layer may be provided on the lens array 133.

[0219] Figure 10B shows an example in which a substrate 120, on which colored layers 132R, 132G, 132B, and a lens array 133 are provided, is bonded to a protective layer 131 by a resin layer 122. By providing the substrate 120 with the colored layers 132R, 132G, 132B, and lens array 133, the temperature of the heat treatment in the formation process can be increased.

[0220] Figure 10B shows an example in which colored layers 132R, 132G, and 132B are provided in contact with the substrate 120, an insulating layer 134 is provided in contact with the colored layers 132R, 132G, and 132B, and a lens array 133 is provided in contact with the insulating layer 134.

[0221] In Figure 10B, the light emitted from the light-emitting device passes through the lens array 133, then through the colored layer, and is extracted to the outside of the display device. Alternatively, the lens array 133 may be provided in contact with the substrate 120, the insulating layer 134 in contact with the lens array 133, and the colored layer in contact with the insulating layer 134. In this case, the light emitted from the light-emitting device passes through the colored layer, then through the lens array 133, and is extracted to the outside of the display device. As shown in Figures 10A and 10B, it is preferable to provide a region where two colored layers overlap between the lens array 133 and adjacent lens arrays 133. By providing a region where colored layers of different colors overlap, color mixing of the light emitted from the light-emitting device can be suppressed.

[0222] Figure 10C shows an example in which a lens array 133 is provided on light-emitting devices 130R, 130G, and 130B via a protective layer 131, and a substrate 120 on which colored layers 132R, 132G, and 132B are provided is bonded to the lens array 133 and the protective layer 131 by a resin layer 122.

[0223] Unlike in Figure 10C, the lens array 133 may be provided on the substrate 120, and the colored layer may be formed directly on the protective layer 131. In this way, one of the lens array and the colored layer may be provided on the protective layer 131, and the other on the substrate 120.

[0224] Figures 10A and 10B show an example in which a layer with planarization function is used as the protective layer 131, but as shown in Figure 10C, the protective layer 131 does not have to have a planarization function. For example, by using an organic film for the protective layer 131, the upper surface of the protective layer 131 can be made flat. Also, the protective layer 131 shown in Figure 10C can be formed by using, for example, an inorganic film.

[0225] Figure 12A shows a top view of a display device 100 different from that shown in Figure 1A. The pixel 110 shown in Figure 12A is composed of four types of sub-pixels: sub-pixels 11R, 11G, 11B, and 11S.

[0226] The sub-pixels 11R, 11G, 11B, and 11S can each be configured to have a light-emitting device that emits light of a different color. For example, the sub-pixels 11R, 11G, 11B, and 11S could be a set of four sub-pixels with R, G, B, and W colors, a set of four sub-pixels with R, G, B, and Y colors, or a set of four sub-pixels with R, G, B, and IR colors.

[0227] Furthermore, a display device according to one aspect of the present invention may have a light-receiving device in each pixel.

[0228] Of the four subpixels of pixel 110 shown in Figure 12A, three may be configured to have light-emitting devices, and the remaining one may be configured to have a light-receiving device.

[0229] 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.

[0230] The light-receiving device can detect either visible light or infrared light, or both. When detecting visible light, it can detect one or more of the following colors, for example, blue, violet, blue-violet, green, yellow-green, yellow, orange, and red. When detecting infrared light, it is preferable because it enables the detection of objects even in dark places.

[0231] 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.

[0232] 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.

[0233] A light-receiving device can detect light incident on it, generate an electric charge, and extract it as an electric current by driving it with a reverse bias applied between the pixel electrode and the common electrode.

[0234] The same manufacturing methods as for light-emitting devices can be applied to light-receiving devices. The island-shaped active layer (also called the photoelectric conversion layer) of the light-receiving device is not formed using a fine metal mask, but rather by processing after depositing a film that will become the active layer onto one surface, thus enabling the formation of an island-shaped active layer with a uniform thickness. Furthermore, by providing a mask layer on the active layer, damage to the active layer during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-receiving device.

[0235] For details regarding the configuration and materials of the light-receiving device, refer to Embodiment 6.

[0236] Figure 12B shows a cross-sectional view between the dashed lines X3 and X4 in Figure 12A. Note that the cross-sectional view between the dashed lines X1 and X2 in Figure 12A can be found in Figure 1B, and the cross-sectional view between the dashed lines Y1 and Y2 can be found in Figure 11A or Figure 11B.

[0237] As shown in Figure 12B, the display device 100 has an insulating layer on a layer 101 containing transistors, an insulating layer on the insulating layer on a light-emitting device 130R and a light-receiving device 150, a protective layer 131 covering the light-emitting device and the light-receiving device, and a substrate 120 bonded to it 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 and light-receiving devices.

[0238] Figure 12B shows an example where the light-emitting device 130R emits light towards the substrate 120, and light is incident on the light-receiving device 150 from the substrate 120 side (see optical Lem and optical Lin).

[0239] The configuration of the light-emitting device 130R is as described above.

[0240] The light-receiving device 150 includes a pixel electrode 111S on an insulating layer 255c, a layer 113S on the pixel electrode 111S, a common layer 114 on the layer 113S, and a common electrode 115 on the common layer 114. The layer 113S includes at least an active layer.

[0241] Here, layer 113S includes at least an active layer and preferably has multiple functional layers. For example, functional layers include carrier transport layers (hole transport layers and electron transport layers) and carrier block layers (hole block layers and electron block layers). It is also preferable to have one or more layers on the active layer. By having other layers between the active layer and the mask layer, it is possible to suppress the exposure of the active layer to the outermost surface during the manufacturing process of the display device and reduce damage to the active layer. This can improve the reliability of the photodetector 150. Therefore, it is preferable that layer 113S includes an active layer and a carrier block layer (hole block layer or electron block layer) or a carrier transport layer (electron transport layer or hole transport layer) on the active layer.

[0242] Layer 113S is provided on the light-receiving device 150 but not on the light-emitting device. However, functional layers other than the active layer included in layer 113S may have the same material as functional layers other than the light-emitting layer included in layers 113B to 113R. On the other hand, the common layer 114 is a continuous layer shared by the light-emitting device and the light-receiving device.

[0243] Here, layers common to both the light-receiving and light-emitting devices may have different functions in the light-emitting device and the light-receiving device. In this specification, components may be referred to based on their function in the light-emitting device. For example, a hole injection layer functions as a hole injection layer in the light-emitting device and as a hole transport layer in the light-receiving device. Similarly, an electron injection layer functions as an electron injection layer in the light-emitting device and as an electron transport layer in the light-receiving device. Furthermore, layers common to both the light-receiving and light-emitting devices may have the same function in the light-emitting device and the light-receiving device. A hole transport layer functions as a hole transport layer in both the light-emitting and light-receiving devices, and an electron transport layer functions as an electron transport layer in both the light-emitting and light-receiving devices.

[0244] A mask layer 118R is located between layer 113R and the insulating layer 125, and a mask layer 118S is located between layer 113S and the insulating layer 125. Mask layer 118R is a portion of the mask layer that remained after processing layer 113R. Mask layer 118S is a portion of the mask layer that remained after processing layer 113S, which is a layer containing the active layer, by being in contact with the upper surface of layer 113S. Mask layer 118B and mask layer 118S may be made of the same material or different materials.

[0245] Figure 12A shows an example in which the aperture ratio (size, also known as the size of the light-emitting or light-receiving area) of sub-pixel 11S is larger than that of sub-pixels 11R, 11G, and 11B, but the present invention is not limited to this. The aperture ratios of sub-pixels 11R, 11G, 11B, and 11S can be determined as appropriate. The aperture ratios of sub-pixels 11R, 11G, 11B, and 11S may be different, or two or more may be equal or approximately equal.

[0246] The sub-pixel 11S may have a higher aperture ratio than at least one of the sub-pixels 11R, 11G, and 11B. A larger light-receiving area for the sub-pixel 11S may make object detection easier. For example, depending on the resolution of the display device and the circuit configuration of the sub-pixels, the aperture ratio of the sub-pixel 11S may be higher than that of the other sub-pixels.

[0247] Furthermore, the aperture ratio of sub-pixel 11S may be lower than that of at least one of sub-pixels 11R, 11G, and 11B. A smaller light-receiving area for sub-pixel 11S results in a narrower imaging range, which helps to suppress blurring in the image and improve resolution. This allows for high-definition or high-resolution imaging, which is preferable.

[0248] Thus, the sub-pixel 11S can be configured with a detection wavelength, resolution, and aperture ratio suitable for the application.

[0249] In one embodiment of the present invention, the display device has an EL layer arranged in an island shape for each light-emitting device, thereby suppressing the occurrence of leakage current between subpixels. This prevents crosstalk caused by unintended light emission, enabling a display device with extremely high contrast. Furthermore, the island-shaped EL layers have dummy regions at the edges and their vicinity, which may be damaged during the manufacturing process of the display device, and these regions are not used as light-emitting areas, thereby suppressing variations in the characteristics of the light-emitting devices. In addition, by providing an insulating layer with a tapered shape at the edges between adjacent island-shaped EL layers, it is possible to suppress the occurrence of step breaks when forming common electrodes and to prevent the formation of locally thin areas in the common electrodes. This suppresses connection failures caused by broken areas and increases in electrical resistance caused by locally thin areas in the common layer and common electrodes. As a result, the display device in one embodiment of the present invention can achieve both high resolution and high display quality.

[0250] This embodiment can be appropriately combined with other embodiments. Also, in this specification, when multiple configuration examples are shown within one embodiment, it is possible to appropriately combine the configuration examples.

[0251] (Embodiment 2) In this embodiment, a method for manufacturing a display device according to an aspect of the present invention will be described using FIGS. 13 to 20. Note that, regarding the materials and formation methods of each element, the description of the parts that are the same as those described in Embodiment 1 above may be omitted. Also, the details of the configuration of the light-emitting device will be described in Embodiment 5.

[0252] In FIGS. 13 to 17, FIGS. 18A, FIGS. 18B, FIG. 19, and FIG. 20, a cross-sectional view between the dashed-dotted line X1 - X2 shown in FIG. 1A and a cross-sectional view between the dashed-dotted line Y1 - Y2 are shown side by side. In FIGS. 18C to 18F, enlarged views of the end portion of the insulating layer 127 and its vicinity are shown.

[0253] The thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed using a sputtering method, a chemical vapor deposition (CVD: Chemical Vapor Deposition) method, a vacuum evaporation method, a pulsed laser deposition (PLD: Pulsed Laser Deposition) method, an atomic layer deposition (ALD: Atomic Layer Deposition) method, or the like. As the CVD method, there are a plasma enhanced CVD (PECVD) method and a thermal CVD method, etc. Also, one of the thermal CVD methods is a metal organic CVD (MOCVD) method.

[0254] Also, the thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by a wet film formation method such as spin coating, dip coating, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0255] 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, hole blocking layer, light-emitting layer, electron blocking layer, electron transport layer, electron injection layer, charge generation 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.).

[0256] 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.

[0257] 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 finally removing the resist mask. The other method involves depositing a photosensitive thin film, then exposing and developing it to process the thin film into the desired shape.

[0258] 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.

[0259] For etching thin films, methods such as dry etching, wet etching, and sandblasting can be used.

[0260] First, insulating layers 255a, 255b, and 255c are formed in this order on the layer 101 containing the transistor. Subsequently, pixel electrodes 111R, 111G, 111B and a conductive layer 123 are formed on the insulating layer 255c (Figure 13A). For example, sputtering or vacuum deposition can be used to form the conductive film that will become the pixel electrode.

[0261] Next, it is preferable to perform a hydrophobic treatment on the pixel electrodes. Hydrophobic treatment can change the surface of the object to be treated from hydrophilic to hydrophobic, or increase the hydrophobicity of the surface of the object to be treated. By performing a hydrophobic treatment on the pixel electrodes, the adhesion between the pixel electrodes and the film (in this case, film 113b) formed in a later step can be improved, and film peeling can be suppressed. However, the hydrophobic treatment is not required.

[0262] Hydrophobic treatment can be performed, for example, by fluorine modification of the pixel electrodes. Fluorine modification can be performed, for example, by treatment with a fluorine-containing gas or heat treatment, or by plasma treatment in a fluorine-containing gas atmosphere. As the fluorine-containing gas, for example, fluorine gas can be used, or for example, fluorocarbon gas can be used. As the fluorocarbon gas, for example, lower fluorinated carbon gases such as carbon tetrafluoride (CF4) gas, C4F6 gas, C2F6 gas, C4F8 gas, and C5F8 can be used. In addition, as the fluorine-containing gas, for example, SF6 gas, NF3 gas, CHF3 gas, etc. can be used. Furthermore, helium gas, argon gas, or hydrogen gas can be added to these gases as appropriate.

[0263] Furthermore, the surface of the pixel electrode can be made hydrophobic by performing plasma treatment in a gas atmosphere containing a group 18 element such as argon, followed by treatment with a silylation agent. Hexamethyldisilazane (HMDS), trimethylsilylimidazole (TMSI), etc., can be used as silylation agents. In addition, the surface of the pixel electrode can also be made hydrophobic by performing plasma treatment in a gas atmosphere containing a group 18 element such as argon, followed by treatment with a silane coupling agent.

[0264] By performing plasma treatment on the surface of the pixel electrode in a gas atmosphere containing a group 18 element such as argon, damage can be inflicted on the surface of the pixel electrode. This makes it easier for methyl groups contained in silylation agents such as HMDS to bond to the surface of the pixel electrode. Furthermore, silane coupling by silane coupling agents becomes more likely to occur. Thus, by performing plasma treatment on the surface of the pixel electrode in a gas atmosphere containing a group 18 element such as argon, followed by treatment with a silylation agent or a silane coupling agent, the surface of the pixel electrode can be made hydrophobic.

[0265] Treatment using silylation agents or silane coupling agents can be carried out by applying the silylation agent or silane coupling agent using methods such as spin coating or dip coating. Alternatively, treatment using silylation agents or silane coupling agents can be carried out by forming a film containing a silylation agent or silane coupling agent on the pixel electrode, for example, using a gas-phase method. In the gas-phase method, first, the silylation agent or silane coupling agent is introduced into the atmosphere by volatilizing the material containing the silylation agent or silane coupling agent. Subsequently, the substrate on which the pixel electrode is formed is placed in this atmosphere. This allows a film containing a silylation agent or silane coupling agent to be formed on the pixel electrode, thereby hydrophobicizing the surface of the pixel electrode.

[0266] Next, a film 113b, which will later become layer 113B, is formed on the pixel electrode (Figure 13A). Film 113b (later layer 113B) contains a light-emitting material that emits blue light. In other words, in this embodiment, island-shaped EL layers for light-emitting devices that emit blue light are formed first, and then island-shaped EL layers for light-emitting devices that emit light of other colors are formed.

[0267] As shown in Figure 13A, in the cross-sectional view between the dashed-dotted line Y1-Y2, no film 113b is formed on the conductive layer 123. For example, by using an area mask, the film 113b can be deposited only in the desired region. By employing a film deposition process using an area mask and a processing process using a resist mask, a light-emitting device can be manufactured using a relatively simple process.

[0268] As described in Embodiment 1, in one embodiment of the present invention, a highly heat-resistant material is used for the light-emitting device in the display device. Specifically, the heat resistance temperature of the compounds contained in the film 113b is preferably 100°C to 180°C, preferably 120°C to 180°C, and more preferably 140°C to 180°C. This improves the reliability of the light-emitting device. It also allows for an increase in the upper limit of the temperature that can be applied during the manufacturing process of the display device. Therefore, the range of materials and forming methods used in the display device can be broadened, leading to improved manufacturing yield and reliability.

[0269] The film 113b can be formed, for example, by a vapor deposition method, specifically a vacuum vapor deposition method. Alternatively, the film 113b may be formed by methods such as a transfer method, a printing method, an inkjet method, or a coating method.

[0270] Next, a mask film 118b, which will later become the mask layer 118B, and a mask film 119b, which will later become the mask layer 119B, are formed in order on film 113b and conductive layer 123, respectively (Figure 13A).

[0271] In this embodiment, an example is shown in which the mask film is formed with a two-layer structure consisting of mask film 118b and mask film 119b, but the mask film may also be a single-layer structure or a laminated structure of three or more layers.

[0272] By providing a mask layer on the film 113b, damage to the film 113b during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-emitting device.

[0273] For the mask film 118b, a film with high resistance to the processing conditions of film 113b is used; specifically, a film with a high etching selectivity ratio with film 113b. For the mask film 119b, a film with a high etching selectivity ratio with mask film 118b is used.

[0274] In addition, the mask films 118b and 119b are formed at a temperature lower than the heat resistance temperature of the film 113b. As the substrate temperature when forming the mask films 118b and 119b, typically, it is 200°C or lower, preferably 150°C or lower, more preferably 120°C or lower, still more preferably 100°C or lower, and even more preferably 80°C or lower, respectively.

[0275] Examples of the index of the heat resistance temperature include the glass transition point, softening point, melting point, thermal decomposition temperature, and 5% weight loss temperature, etc. The heat resistance temperature of the films 113b, 113g, 113r (that is, the layers 113B, 113G, 113R) can be any of these temperatures serving as the index of the heat resistance temperature, preferably the lowest temperature among these.

[0276] As described above, in the display device according to one aspect of the present invention, a material with high heat resistance is used for the light-emitting device. Therefore, the substrate temperature when forming the mask film can also be 100°C or higher, 120°C or higher, or 140°C or higher. For example, the higher the film formation temperature of the inorganic insulating film, the denser and higher the barrier property the film can be. Therefore, by forming the mask film at such a temperature, the damage to the film 113b can be further reduced, and the reliability of the light-emitting device can be enhanced.

[0277] It is preferable to use a film that can be removed by the wet etching method for the mask films 118b and 119b. By using the wet etching method, the damage applied to the film 113b during the processing of the mask films 118b and 119b can be reduced compared to the case of using the dry etching method.

[0278] For the formation of the mask films 118b and 119b, for example, the sputtering method, ALD method (including thermal ALD method and PEALD method), CVD method, and vacuum evaporation method can be used. Further, it may be formed using the aforementioned wet film formation method.

[0279] Furthermore, it is preferable that the mask film 118b, which is formed in contact with film 113b, is formed using a method that causes less damage to film 113b than the mask film 119b. For example, it is preferable to form the mask film 118b using the ALD method or vacuum deposition method rather than the sputtering method.

[0280] For the mask film 118b and the mask film 119b, one or more types can be used, for example, from among metal films, alloy films, metal oxide films, semiconductor films, organic insulating films, and inorganic insulating films.

[0281] The mask films 118b and 119b 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 rays in one or both of the mask films 118b and 119b, as this can suppress the irradiation of film 113b with ultraviolet rays and thus suppress the degradation of film 113b.

[0282] Furthermore, using a metal film or alloy film for one or both of the mask films 118b and 119b is preferable because it can suppress plasma damage to film 113b and thus suppress degradation of film 113b. Specifically, it is possible to suppress plasma damage to film 113b in processes such as dry etching and ashing. In particular, it is preferable to use a metal film such as a tungsten film or an alloy film as the mask film 119b.

[0283] Furthermore, the mask films 118b and 119b can be made from metal oxides such as In-Ga-Zn oxide, 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), and silicon-containing indium tin oxide, respectively.

[0284] 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.

[0285] Furthermore, a film containing a material that has light-shielding properties against light, particularly ultraviolet light, can be used as the mask film. For example, a film that reflects ultraviolet light or a film that absorbs ultraviolet light can be used. Various materials can be used as the light-shielding material, such as metals, insulators, semiconductors, and metalloids that have light-shielding properties against ultraviolet light. However, since part or all of the mask film will be removed in a later process, it is preferable that the film be processable by etching, and in particular, that it has good processability.

[0286] For example, semiconductor materials such as silicon or germanium can be used as materials with high affinity to semiconductor manufacturing processes. Alternatively, oxides or nitrides of the above semiconductor materials can be used. Alternatively, nonmetallic materials such as carbon, or compounds thereof, can be used. Alternatively, metals such as titanium, tantalum, tungsten, chromium, and aluminum, or alloys containing one or more of these, can be used. Alternatively, oxides containing the above metals such as titanium oxide or chromium oxide, or nitrides such as titanium nitride, chromium nitride, or tantalum nitride can be used.

[0287] By using a mask film containing a material that blocks ultraviolet light, it is possible to suppress the irradiation of the EL layer with ultraviolet light during the exposure process. By suppressing damage to the EL layer from ultraviolet light, the reliability of the light-emitting device can be improved.

[0288] Furthermore, a film containing a material that has light-shielding properties against ultraviolet rays can be used as the material for the insulating film 125A, as described later, to achieve the same effect.

[0289] Furthermore, various inorganic insulating films that can be used in the protective layer 131 can be used as mask films 118b and 119b, respectively. In particular, oxide insulating films are preferred because they have higher adhesion to film 113b compared to nitride insulating films. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used as mask films 118b and 119b, respectively. For example, aluminum oxide films can be formed as mask films 118b and 119b using the ALD method. Using the ALD method is preferred because it reduces damage to the substrate (especially the EL layer).

[0290] For example, an inorganic insulating film (e.g., an aluminum oxide film) formed using the ALD method can be used as the mask film 118b, and an inorganic film (e.g., an In-Ga-Zn oxide film, a silicon film, or a tungsten film) formed using the sputtering method can be used as the mask film 119b.

[0291] Furthermore, the same inorganic insulating film can be used for both the mask film 118b and the insulating layer 125 that is formed later. For example, an aluminum oxide film formed using the ALD method can be used for both the mask film 118b and the insulating layer 125. Here, the same film formation conditions may be applied to the mask film 118b and the insulating layer 125, or different film formation conditions may be applied to each. For example, by forming the mask film 118b under the same conditions as the insulating layer 125, the mask film 118b can be made into an insulating layer with high barrier properties against at least one of water and oxygen. On the other hand, since the mask film 118b is a layer that will be mostly or completely removed in a later process, it is preferable that it be easy to process. Therefore, it is preferable to form the mask film 118b under conditions where the substrate temperature during film formation is lower than that of the insulating layer 125.

[0292] Organic materials may be used in one or both of the mask films 118b and 119b. For example, as the organic material, a material that is soluble in a solvent that is chemically stable to the film located at least on top of film 113b may be used. Materials that are soluble in water or alcohol are particularly suitable. When forming such a film, it is preferable to dissolve the material in a solvent such as water or alcohol, apply it using a wet film formation method, and then perform a heat treatment to evaporate the solvent. At this time, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to film 113b.

[0293] Mask films 118b and 119b may each be made of organic resins such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, alcohol-soluble polyamide resin, or fluoropolymers.

[0294] For example, an organic film (e.g., a PVA film) formed using either a vapor deposition method or the wet film formation method described above can be used as the mask film 118b, and an inorganic film (e.g., a silicon nitride film) formed using a sputtering method can be used as the mask film 119b.

[0295] As described in Embodiment 1, in one embodiment of the present invention, a portion of the mask film may remain as a mask layer in the display device.

[0296] Next, a resist mask 190B is formed on the mask film 119b (Figure 13A). The resist mask 190B can be formed by applying a photosensitive resin (photoresist), followed by exposure and development.

[0297] The resist mask 190B may be made using either a positive-type resist material or a negative-type resist material.

[0298] The resist mask 190B is provided in a position that overlaps with the pixel electrode 111B. Preferably, the resist mask 190B is also provided in a position that overlaps with the conductive layer 123. This helps to suppress damage to the conductive layer 123 during the manufacturing process of the display device. Note that it is not necessary to provide the resist mask 190B on the conductive layer 123.

[0299] Furthermore, it is preferable that the resist mask 190B be provided so as to cover from the edge of film 113b to the edge of conductive layer 123 (the edge on the film 113b side), as shown in the cross-sectional view between Y1 and Y2 in Figure 13A. This ensures that even after processing the mask films 118b and 119b, the edges of the mask layers 118B and 119B overlap with the edge of film 113b. Also, since the mask layers 118B and 119B are provided so as to cover from the edge of film 113b to the edge of conductive layer 123 (the edge on the film 113b side), exposure of the insulating layer 255c can be suppressed even after processing film 113b (see the cross-sectional view between Y1 and Y2 in Figure 14B). This prevents the insulating layers 255a to 255c and a portion of the insulating layer included in the layer 101 containing the transistor from being lost due to etching or the like, and prevents the conductive layer included in the layer 101 containing the transistor from being exposed. Therefore, it is possible to suppress the unintentional electrical connection of the conductive layer with other conductive layers. For example, it is possible to suppress a short circuit between the conductive layer and the common electrode 115.

[0300] Next, a portion of the mask film 119b is removed using the resist mask 190B to form the mask layer 119B (Figure 13B). The mask layer 119B remains on the pixel electrode 111B and on the conductive layer 123. After that, the resist mask 190B is removed (Figure 13C). Subsequently, the mask layer 119B is used as a mask (also called a hard mask) to remove a portion of the mask film 118b to form the mask layer 118B (Figure 14A).

[0301] Mask films 118b and 119b can be processed by wet etching or dry etching, respectively. It is preferable to process mask films 118b and 119b by anisotropic etching.

[0302] By using the wet etching method, the damage to film 113b during processing of mask films 118b and 119b 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.

[0303] In the processing of the mask film 119b, the film 113b is not exposed, so there is a wider range of processing methods to choose from compared to the processing of the mask film 118b. Specifically, when processing the mask film 119b, even if an oxygen-containing gas is used as the etching gas, the degradation of the film 113b can be further suppressed.

[0304] Furthermore, when using a dry etching method for processing the mask film 118b, the degradation of film 113b can be suppressed by not using an oxygen-containing gas as the etching gas. When using a 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.

[0305] For example, when using an aluminum oxide film formed by the ALD method as the mask film 118b, the mask film 118b can be processed by dry etching using CHF3 and He, or CHF3, He, and CH4. Also, when using an In-Ga-Zn oxide film formed by the sputtering method as the mask film 119b, the mask film 119b can be processed by wet etching using diluted phosphoric acid. Alternatively, it may be processed by dry etching using CH4 and Ar. Alternatively, the mask film 119b can be processed by wet etching using diluted phosphoric acid. Furthermore, when using a tungsten film formed by the sputtering method as the mask film 119b, the mask film 119b can be processed by dry etching using SF6, CF4, and O2, or CF4, Cl2, and O2.

[0306] The resist mask 190B can be removed, for example, by ashing using oxygen plasma. Alternatively, oxygen gas and a noble gas such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He may be used. Alternatively, the resist mask 190B may be removed by wet etching. In this case, since the mask film 118b is located on the outermost surface and film 113b is not exposed, damage to film 113b can be suppressed during the removal process of the resist mask 190B. Furthermore, the range of selectable methods for removing the resist mask 190B can be broadened.

[0307] Next, the film 113b is processed to form layer 113B. For example, mask layer 119B and mask layer 118B are used as a hard mask to remove a portion of film 113b and form layer 113B (Figure 14B).

[0308] As a result, as shown in Figure 14B, the stacked structure of layer 113B, mask layer 118B, and mask layer 119B remains on the pixel electrode 111B. In addition, the pixel electrodes 111R and 111G are exposed.

[0309] Here, when processing film 113b, the surfaces of pixel electrode 111R and pixel electrode 111G are exposed to etching gas or etching solution. On the other hand, the surface of pixel electrode 111B is not exposed to etching gas or etching solution. In this way, in the light-emitting device of the first color formed, the surface of the pixel electrode is not damaged by the etching process, and the state of the interface between the pixel electrode and the EL layer can be maintained in good condition.

[0310] The film 113b is preferably processed by anisotropic etching. In particular, anisotropic dry etching is preferred. Alternatively, wet etching may be used.

[0311] Figure 14B shows an example of processing film 113b by dry etching. Inside the dry etching apparatus, the etching gas is converted into plasma. Therefore, the surface of the display device being fabricated is exposed to plasma (plasma 121a). Here, it is preferable to use a metal film or alloy film for one or both of the mask layer 118B and mask layer 119B, as this can suppress plasma damage to the remaining portion of film 113b (the portion that becomes layer 113B) and thus suppress the deterioration of layer 113B. In particular, it is preferable to use a metal film such as a tungsten film or an alloy film as the mask layer 119B.

[0312] When using the dry etching method, the degradation of film 113b can be suppressed by not using an oxygen-containing gas as the etching gas.

[0313] 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 film 113b. Additionally, it suppresses problems such as the adhesion of reaction products generated during etching.

[0314] When using the dry etching method, it is preferable to use an etching gas containing one or more of the following noble gases: 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. Furthermore, for example, a gas containing H2 and Ar, and a gas containing oxygen can be used as the etching gas.

[0315] As a dry etching apparatus, a dry etching apparatus having a high-density plasma source can be used. A dry etching apparatus having a high-density plasma source can be, for example, an inductively coupled plasma (ICP) etching apparatus. Alternatively, a capacitively coupled plasma (CCP) etching apparatus having parallel plate electrodes can be used. A capacitively coupled plasma etching apparatus having parallel plate electrodes may be configured to apply a high-frequency voltage to one electrode of the parallel plate electrodes. Alternatively, it may be configured to apply multiple different high-frequency voltages to one electrode of the parallel plate electrodes. Alternatively, it may be configured to apply a high-frequency voltage of the same frequency to each of the parallel plate electrodes. Alternatively, it may be configured to apply high-frequency voltages of different frequencies to each of the parallel plate electrodes.

[0316] Figure 14B shows an example where the edge of layer 113B is located outside the edge of the pixel electrode 111B. This configuration allows for a higher aperture ratio of the pixels. Although not shown in Figure 14B, the etching process may result in the formation of recesses in areas of the insulating layer 255c that do not overlap with layer 113B.

[0317] Furthermore, since layer 113B covers the top and sides of the pixel electrode 111B, subsequent processes can be carried out without exposing the pixel electrode 111B. If the edges of the pixel electrode 111B are exposed, corrosion may occur during processes such as etching. Products generated by the corrosion of the pixel electrode 111B 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 layer 113B, 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 the pixel electrode 111B are exposed, the adhesion between layers in contact with each other decreases, which may make peeling of layer 113B or the pixel electrode 111B more likely.

[0318] Therefore, by configuring layer 113B to cover the top and side surfaces of pixel electrode 111B, for example, the yield and characteristics of the light-emitting device can be improved.

[0319] Furthermore, as described in Embodiment 1, since layer 113B covers the upper and side surfaces of the pixel electrode 111B, a dummy region is provided in layer 113B outside the light-emitting region (the region located between the pixel electrode 111B and the common electrode 115). Here, the edges of layer 113B may be damaged during the processing of film 113b. Also, the edges of layer 113B may be damaged by exposure to plasma in subsequent processes (see plasma 121b in Figure 16A and plasma 121c in Figure 16C). Since the edges of layer 113B and their vicinity are dummy regions and are not used for light emission, even if they are damaged, it is unlikely to adversely affect the characteristics of the light-emitting device. On the other hand, since the light-emitting region of layer 113B is covered by the mask layer, it is not exposed to plasma, and damage from plasma is sufficiently reduced. The mask layer is preferably provided not only to cover the upper surface of the flat portion of layer 113B that overlaps with the upper surface of the pixel electrode 111B, but also to cover the inclined portion and the upper surface of the flat portion located outside the upper surface of the pixel electrode 111B. In this way, since the portion of layer 113B in which damage during the manufacturing process is suppressed is used as the light-emitting region, a light-emitting device with high luminous efficiency and a long lifespan can be realized.

[0320] Furthermore, in the region corresponding to the connection portion 140, the laminated structure of the mask layer 118B and the mask layer 119B remains on the conductive layer 123.

[0321] As mentioned above, in the cross-sectional view between Y1 and Y2 in Figure 14B, the mask layers 118B and 119B are provided so as to cover the ends of layer 113B and the conductive layer 123, and the upper surface of the insulating layer 255c is not exposed. Therefore, it is possible to prevent the insulating layers 255a to 255c and a portion of the insulating layer included in layer 101 containing the transistor from being removed by etching or the like, and to prevent the conductive layer included in layer 101 containing the transistor from being exposed. As a result, it is possible to suppress the conductive layer from being unintentionally electrically connected to other conductive layers.

[0322] As described above, in one aspect of the present invention, a resist mask 190B is formed on a mask film 119b, and a mask layer 119B is formed by removing a portion of the mask film 119b using the resist mask 190B. Subsequently, a layer 113B is formed by removing a portion of the film 113b using the mask layer 119B as a hard mask. Thus, it can be said that a layer 113B is formed by processing the film 113b using a photolithography method. Note that a portion of the film 113b may be removed using the resist mask 190B. Subsequently, the resist mask 190B may be removed.

[0323] Next, it is preferable to perform a hydrophobic treatment on the pixel electrodes. During the processing of film 113b, the surface state of the pixel electrodes may change to hydrophilic. By performing a hydrophobic treatment on the pixel electrodes, the adhesion between the pixel electrodes and the film (in this case, film 113g) formed in a later process can be improved, and film peeling can be suppressed. However, the hydrophobic treatment is not required.

[0324] Next, a film 113g, which will later become layer 113G, is formed on the pixel electrodes 111R and 111G, and on the mask layer 119B (Figure 14C). Film 113g (later layer 113G) contains a light-emitting material that emits green light. In other words, this embodiment shows an example in which an island-shaped EL layer for a light-emitting device that emits green light is formed secondly. However, the present invention is not limited to this, and an island-shaped EL layer for a light-emitting device that emits red light may also be formed secondly.

[0325] The film 113g can be formed by a method similar to the method used to form film 113b.

[0326] Next, a mask film 118g, which will later become mask layer 118G, and a mask film 119g, which will later become mask layer 119G, are formed sequentially on film 113g, and then the resist mask 190G is formed (Figure 14C). The materials and formation methods for mask films 118g and 119g are the same as those applicable to mask films 118b and 119b. The materials and formation methods for resist mask 190G are the same as those applicable to resist mask 190B.

[0327] The resist mask 190G is positioned to overlap with the pixel electrode 111G.

[0328] Next, a portion of the mask film 119g is removed using the resist mask 190G to form the mask layer 119G (Figure 15A). The mask layer 119G remains on the pixel electrode 111G. After that, the resist mask 190G is removed (Figure 15B). Next, the mask layer 119G is used as a mask to remove a portion of the mask film 118g to form the mask layer 118G (Figure 15C). Next, the film 113g is processed to form the layer 113G. For example, the mask layer 119G and the mask layer 118G are used as a hard mask to remove a portion of the film 113g to form the layer 113G (Figure 16A).

[0329] Here, when processing the film 113g, the surface of the pixel electrode 111R is exposed to etching gas or etching solution. On the other hand, the surfaces of the pixel electrode 111B and the pixel electrode 111G are not exposed to etching gas or etching solution. In other words, in the second color light-emitting device formed, the surface of the pixel electrode is exposed in one etching step, and in the third color light-emitting device formed, the surface of the pixel electrode is exposed in two etching steps. For this reason, it is preferable to form the island-shaped EL layer earlier for light-emitting devices in which the surface condition of the pixel electrode is more likely to affect the characteristics. This makes it possible to improve the characteristics of each color light-emitting device.

[0330] Figure 16A shows an example of processing film 113g by dry etching. The surface of the display device during fabrication is exposed to plasma (plasma 121b). Here, it is preferable to use a metal film or alloy film for one or both of the mask layers 118B and 119B, as this can suppress plasma damage to layer 113B and thus suppress deterioration of layer 113B. It is also preferable to use a metal film or alloy film for one or both of the mask layers 118G and 119G, as this can suppress plasma damage to the remaining portion of film 113g (layer 113G) and thus suppress deterioration of layer 113G. In particular, it is preferable to use a metal film such as a tungsten film or an alloy film as the mask layer 119G.

[0331] As a result, as shown in Figure 16A, the stacked structure of layer 113G, mask layer 118G, and mask layer 119G remains on the pixel electrode 111G. In addition, the mask layer 119B and the pixel electrode 111R are exposed.

[0332] Next, it is preferable to perform a hydrophobic treatment on the pixel electrodes. During processing of the film 113g, the surface state of the pixel electrodes may change to hydrophilic. By performing a hydrophobic treatment on the pixel electrodes, the adhesion between the pixel electrodes and the film (in this case, film 113r) formed in a later process can be improved, and film peeling can be suppressed. However, the hydrophobic treatment is not required.

[0333] Next, a film 113r, which will later become layer 113R, is formed on the pixel electrode 111R and on the mask layers 119G and 119B (Figure 16B).

[0334] The film 113r (later layer 113R) contains a light-emitting material that emits red light.

[0335] The film 113r can be formed in a manner similar to that used for forming the film 113b.

[0336] Next, a mask film 118r, which will later become the mask layer 118R, and a mask film 119r, which will later become the mask layer 119R, are formed sequentially on the film 113r, and then the resist mask 190R is formed (Figure 16B). The materials and formation methods for the mask films 118r and 119r are the same as those applicable to the mask films 118b and 119b. The materials and formation methods for the resist mask 190R are the same as those applicable to the resist mask 190B.

[0337] The resist mask 190R is positioned to overlap with the pixel electrode 111R.

[0338] Next, a resist mask 190R is used to remove a portion of the mask film 119r, forming a mask layer 119R. The mask layer 119R remains on the pixel electrode 111R. After that, the resist mask 190R is removed. Next, the mask layer 119R is used as a mask to remove a portion of the mask film 118r, forming a mask layer 118R. Next, the film 113r is processed to form layer 113R. For example, the mask layer 119R and the mask layer 118R are used as a hard mask to remove a portion of the film 113r, forming layer 113R (Figure 16C).

[0339] Figure 16C shows an example of processing film 113r by dry etching. The surface of the display device during fabrication is exposed to plasma (plasma 121c). Here, it is preferable to use a metal film or alloy film on one or both of mask layers 118B and 119B, and on one or both of mask layers 118G and 119G, respectively, as this suppresses plasma damage to layers 113B and 113G and inhibits degradation of layers 113B and 113G. It is also preferable to use a metal film or alloy film on one or both of mask layers 118R and 119R, as this suppresses plasma damage to the remaining portion of film 113r (layer 113R) and inhibits degradation of layer 113R. In particular, it is preferable to use a metal film such as a tungsten film or an alloy film as mask layer 119R.

[0340] As a result, as shown in Figure 16C, the stacked structure of layer 113R, mask layer 118R, and mask layer 119R remains on the pixel electrode 111R. In addition, mask layers 119G and 119B are exposed.

[0341] Furthermore, it is preferable that the sides of layers 113B, 113G, and 113R 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° or more and 90° or less.

[0342] As described above, the distance between two adjacent layers of layers 113B, 113G, and 113R formed using photolithography can be narrowed to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Here, this distance can be defined, for example, as the distance between two adjacent opposing ends of layers 113B, 113G, and 113R. By narrowing the distance between the island-shaped EL layers in this way, a display device with high resolution and a large aperture ratio can be provided.

[0343] Next, it is preferable to remove the mask layers 119B, 119G, and 119R (Figure 17A). Depending on subsequent processes, the mask layers 118B, 118G, 118R, 119B, 119G, and 119R may remain in the display device. By removing the mask layers 119B, 119G, and 119R at this stage, it is possible to suppress the remaining mask layers 119B, 119G, and 119R in the display device. For example, if conductive material is used for the mask layers 119B, 119G, and 119R, removing the mask layers 119B, 119G, and 119R in advance can suppress the generation of leakage current and the formation of capacitance due to the remaining mask layers 119B, 119G, and 119R.

[0344] In this embodiment, the case where mask layers 119B, 119G, and 119R are removed is described as an example, but it is not necessary to remove mask layers 119B, 119G, and 119R. For example, if mask layers 119B, 119G, and 119R contain the aforementioned material that has light-shielding properties against ultraviolet rays, it is preferable to proceed to the next step without removing them, as this protects the island-shaped EL layer from ultraviolet rays.

[0345] The same method as the mask layer processing method can be used for the mask layer removal process. In particular, by using the wet etching method, the damage inflicted on layers 113B, 113G, and 113R when removing the mask layer can be reduced compared to when using the dry etching method.

[0346] When metal or alloy films are used for the mask layers 119B, 119G, and 119R, the presence of these mask layers helps to suppress plasma damage to the EL layer. Therefore, the film can be processed using a dry etching method in the process up to the removal of the mask layers 119B, 119G, and 119R. On the other hand, in the process of removing the mask layers 119B, 119G, and 119R, and in the subsequent processes, the film that suppresses plasma damage to the EL layer is gone, so it is preferable to process the film using a method that does not use plasma, such as a wet etching method.

[0347] Alternatively, the mask 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.

[0348] After removing the mask layer, a drying treatment may be performed to remove water contained in layers 113B, 113G, and 113R, and water adsorbed on the surfaces of layers 113B, 113G, and 113R. For example, a heat treatment can be performed in an inert gas atmosphere such as a nitrogen 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.

[0349] Next, an insulating film 125A, which will later become the insulating layer 125, is formed to cover the pixel electrode, layer 113B, layer 113G, layer 113R, mask layer 118B, mask layer 118G, and mask layer 118R (Figure 17A).

[0350] As described later, the insulating film 127a is formed in contact with the upper surface of the insulating film 125A. For this reason, it is preferable that the upper surface of the insulating film 125A has high adhesion to the resin composition used for the insulating film 127a (for example, a photosensitive resin composition containing acrylic resin). To improve this adhesion, it is preferable to hydrophobize (or increase the hydrophobicity of) the upper surface of the insulating film 125A by performing a surface treatment. For example, it is preferable to perform the treatment using a silylation agent such as hexamethyldisilazane (HMDS). By hydrophobizing the upper surface of the insulating film 125A in this way, the insulating film 127a can be formed with good adhesion. The aforementioned hydrophobic treatment may be performed as the surface treatment.

[0351] Next, insulating film 127a is formed on insulating film 125A (Figure 17B).

[0352] It is preferable that insulating film 125A and insulating film 127a are formed using a method that causes minimal damage to layers 113B, 113G, and 113R. In particular, since insulating film 125A is formed in contact with the sides of layers 113B, 113G, and 113R, it is preferable that it be formed using a method that causes less damage to layers 113B, 113G, and 113R than insulating film 127a.

[0353] Furthermore, insulating film 125A and insulating film 127a are formed at a temperature lower than the heat resistance temperature of layers 113B, 113G, and 113R, respectively. In addition, by increasing the substrate temperature during film formation of insulating film 125A, it is possible to create a film with a low impurity concentration and high barrier properties against at least one of water and oxygen, even with a thin film thickness.

[0354] The substrate temperature when forming insulating film 125A and insulating film 127a is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher, and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower, respectively.

[0355] As described above, in one embodiment of the present invention, a highly heat-resistant material is used for the light-emitting device. Therefore, the substrate temperature when forming the insulating film 125A and insulating film 127a can be set to 100°C or higher, 120°C or higher, or 140°C or higher, respectively. For example, the higher the deposition temperature of the inorganic insulating film, the denser and more barrier-oriented the film can be. Therefore, by depositing the insulating film 125A at such a temperature, the damage to layers 113B, 113G, and 113R can be further reduced, and the reliability of the light-emitting device can be improved.

[0356] As the insulating film 125A, it is preferable to form an insulating film with a thickness of 3 nm or more, 5 nm or more, or 10 nm or more, and a thickness of 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less, within the above substrate temperature range.

[0357] The insulating film 125A is preferably formed using, for example, the ALD method. The ALD method is preferable because it can reduce film formation damage and allow for the formation of a highly covering film. For example, it is preferable to form an aluminum oxide film as the insulating film 125A using the ALD method.

[0358] In addition, the insulating film 125A may be formed using a sputtering method, CVD method, or PECVD method, which have a faster deposition rate than the ALD method. This allows for the production of highly reliable display devices with high productivity.

[0359] The insulating film 127a is preferably formed using the wet film formation method described above. The insulating film 127a is preferably formed using a photosensitive resin, for example, by spin coating, and more specifically, it is preferably formed using a photosensitive resin composition containing an acrylic resin.

[0360] Furthermore, it is preferable to perform a heat treatment (also called pre-baking) after the formation of the insulating film 127a. This heat treatment is performed at a temperature lower than the heat resistance temperature of layers 113B, 113G, and 113R. The substrate temperature during the heat treatment is preferably 50°C to 200°C, more preferably 60°C to 150°C, and even more preferably 70°C to 120°C. This makes it possible to remove the solvent contained in the insulating film 127a.

[0361] Next, visible light or ultraviolet light is irradiated onto a portion of the insulating film 127a to expose that portion (Figure 17C). Here, if a positive-type photosensitive resin composition containing acrylic resin is used for the insulating film 127a, visible light or ultraviolet light is irradiated using a mask 132 in the area where the insulating layer 127 will not be formed in a later step. The insulating layer 127 is formed in the area sandwiched between any two of the pixel electrodes 111R, 111G, and 111B, and around the conductive layer 123. Therefore, as shown in Figure 17C, light is irradiated onto the portion of the insulating film 127a that overlaps with the pixel electrode 111R, the portion that overlaps with the pixel electrode 111G, the portion that overlaps with the pixel electrode 111B, and the portion that overlaps with the conductive layer 123.

[0362] Furthermore, the width of the insulating layer 127 to be formed later can be controlled by the area exposed to light at this stage. In this embodiment, the insulating layer 127 is processed so that it has a portion that overlaps with the upper surface of the pixel electrode (Figure 2A). As shown in Figure 5A or Figure 5B, the insulating layer 127 does not have to have a portion that overlaps with the upper surface of the pixel electrode.

[0363] The light used for exposure preferably includes the i-line (wavelength 365 nm). Furthermore, the light used for exposure may also include at least one of the g-line (wavelength 436 nm) and the h-line (wavelength 405 nm).

[0364] In Figure 17C, an example is shown in which a positive-type photosensitive resin is used for the insulating film 127a and visible light or ultraviolet light is irradiated into the area where the insulating layer 127 is not formed. However, the present invention is not limited to this. For example, a negative-type photosensitive resin may be used for the insulating film 127a. In this case, visible light or ultraviolet light is irradiated into the area where the insulating layer 127 is formed.

[0365] Next, as shown in Figure 18A, development is performed to remove the exposed area of ​​the insulating film 127a and form the insulating layer 127b. The insulating layer 127b is formed in the area sandwiched between any two of the pixel electrodes 111R, 111G, and 111B, and in the area surrounding the conductive layer 123. Here, when acrylic resin is used for the insulating film 127a, it is preferable to use an alkaline solution as the developer, for example, an aqueous solution of tetramethylammonium hydroxide (TMAH) can be used.

[0366] Furthermore, after development, a process to remove development residue (so-called scum) may be performed. For example, residue can be removed by ashing using oxygen plasma. After each of the development processes described below, a process to remove residue may also be performed.

[0367] Furthermore, etching may be performed to adjust the surface height of the insulating layer 127b. The insulating layer 127b may also be processed, for example, by ashing using oxygen plasma.

[0368] Alternatively, after development and before post-baking, the entire substrate may be exposed to visible or ultraviolet light to irradiate the insulating layer 127b. The energy density of this exposure is 0 mJ / cm². 2 Even larger, 800 mJ / cm 2The following is preferable: 0 mJ / cm 2 Larger, 500 mJ / cm 2 The following is more preferable: Performing such exposure after development may improve the transparency of the insulating layer 127b. In addition, it may be possible to deform the insulating layer 127b into a tapered shape at a low temperature.

[0369] On the other hand, by not exposing the insulating layer 127b, it may be easier to change the shape of the insulating layer 127b or to deform the insulating layer 127 into a tapered shape in a later process. Therefore, it may be preferable not to expose the insulating layer 127b after development.

[0370] Next, a heat treatment (also called post-bake) is performed. As shown in Figure 18B, by performing the heat treatment, the insulating layer 127b can be deformed into an insulating layer 127 having a tapered shape on its side surface. This heat treatment is performed at a temperature lower than the heat resistance temperature of the EL layer. 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 130°C. The heating atmosphere may be an atmospheric atmosphere or an inert gas atmosphere. The heating atmosphere may also be an atmospheric pressure atmosphere or a reduced pressure atmosphere. A reduced pressure atmosphere is preferable because it allows drying at a lower temperature. It is preferable to use a higher substrate temperature for the heat treatment in this step than for the heat treatment after the formation of the insulating film 127a (pre-bake). This improves the adhesion between the insulating layer 127 and the insulating layer 125, and also improves the corrosion resistance of the insulating layer 127.

[0371] Furthermore, depending on the material of the insulating layer 127, as well as the post-bake temperature, time, and atmosphere, a concave curved shape may be formed on the side surface of the insulating layer 127, as shown in Figures 4A and 4B. For example, the higher the temperature or the longer the post-bake conditions, the more likely the shape of the insulating layer 127 is to change, and a concave curved shape may be formed. Also, as mentioned above, if the insulating layer 127b is not exposed after development, the shape of the insulating layer 127 may change during post-bake.

[0372] Next, as shown in Figure 18B, etching is performed using the insulating layer 127 as a mask to remove the insulating film 125A and a portion of the mask layers 118B, 118G, and 118R. This creates openings in the mask layers 118B, 118G, and 118R, exposing the upper surfaces of layers 113G, 113G, 113R, and the conductive layer 123.

[0373] The etching process can be carried out by dry etching or wet etching. It is preferable that the insulating film 125A is deposited using the same material as the mask layers 118B, 118G, and 118R, as this allows the etching process to be performed in a single step.

[0374] When performing dry etching, it is preferable to use a chlorine-based gas. As chlorine-based gases, Cl2, BCl3, SiCl4, and CCl4 can be used individually or in mixtures of two or more gases. In addition, one or more gases such as oxygen gas, hydrogen gas, helium gas, and argon gas can be appropriately mixed with the above chlorine-based gas. By using dry etching, thin areas of the mask layers 118B, 118G, and 118R can be formed with good in-plane uniformity.

[0375] Furthermore, when dry etching is performed, by-products generated during dry etching may accumulate on the upper and side surfaces of the insulating layer 127b. As a result, components contained in the etching gas, components contained in the insulating film 125A, and components contained in the mask layers 118B, 118G, and 118R may be present in the insulating layer 127 after the display device is completed.

[0376] Furthermore, it is preferable to perform the etching process by wet etching. By using the wet etching method, damage to layers 113B, 113G, and 113R can be reduced compared to when using the dry etching method. For example, wet etching can be performed using an alkaline solution. For example, for wet etching of an aluminum oxide film, it is preferable to use an aqueous solution of tetramethylammonium hydroxide (TMAH), which is an alkaline solution. In this case, wet etching can be performed using a paddle method.

[0377] As described above, by providing insulating layer 127, insulating layer 125, mask layer 118B, mask layer 118G, and mask layer 118R, connection failures caused by interruptions and increases in electrical resistance caused by locally thin film thicknesses can be suppressed between each light-emitting device in the common layer 114 and common electrode 115. As a result, a display device according to one embodiment of the present invention can improve display quality.

[0378] Furthermore, after exposing a portion of layers 113B, 113G, and 113R, a further heat treatment may be performed. This heat treatment can remove water contained in the EL layer and water adsorbed on the surface of the EL layer. In addition, this heat treatment may change the shape of the insulating layer 127. Specifically, the insulating layer 127 may spread to cover at least one of the following: the edge of the insulating layer 125, the edges of the mask layers 118B, 118G, and 118R, and the upper surfaces of layers 113B, 113G, and 113R. For example, the insulating layer 127 may take on the shape shown in Figures 3A and 3B. For example, the 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 for dehydration at a lower temperature. However, it is preferable to set the temperature range for the above heat treatment appropriately, taking into consideration the heat resistance temperature of the EL layer. When considering the heat resistance temperature of the EL layer, a temperature of 70°C to 120°C is particularly preferable within the above temperature range.

[0379] If the etching process for the insulating layer 125 and the mask layer is performed all at once after post-baking, side etching may cause the insulating layer 125 and the mask layer beneath the edges of the insulating layer 127 to disappear, forming a cavity. This cavity can cause unevenness on the surface forming the common layer 114 and the common electrode 115, making it easier for the common layer 114 and the common electrode 115 to break down. Therefore, it is preferable to perform the etching process for the insulating layer 125 and the mask layer separately, before and after post-baking.

[0380] In the following section, using Figures 18C to 18F, we will explain a method in which the etching process of the insulating layer 125 and the mask layer is performed separately before and after post-baking.

[0381] First, Figure 18C shows an enlarged view of the edge and vicinity of layer 113G and insulating layer 127b shown in Figure 18A. In other words, Figure 18C shows the insulating layer 127b formed by development.

[0382] Next, as shown in Figure 18D, etching is performed using the insulating layer 127b as a mask to remove a portion of the insulating film 125A and thin the film thickness of parts of the mask layers 118B, 118G, and 118R. As a result, the insulating layer 125 is formed beneath the insulating layer 127b. In addition, the surfaces of the thinned portions of the mask layers 118B, 118G, and 118R are exposed. In the following, the etching process using the insulating layer 127b as a mask may be referred to as the first etching process.

[0383] The first etching process can be carried out by dry etching or wet etching.

[0384] As shown in Figure 18D, by etching using the insulating layer 127b, which has a tapered side surface, as a mask, the side surface of the insulating layer 125 and the upper edges of the side surfaces of the mask layers 118B, 118G, and 118R can be made tapered relatively easily.

[0385] As shown in Figure 18D, in the first etching process, the mask layers 118B, 118G, and 118R are not completely removed, and the etching process is stopped when the film thickness is reduced. By leaving the corresponding mask layers 118B, 118G, and 118R on layers 113B, 113G, and 113R in this way, it is possible to prevent damage to layers 113B, 113G, and 113R in subsequent processing steps.

[0386] In Figure 18D, the mask layers 118B, 118G, and 118R are configured to have thinner films, but the present invention is not limited to this. For example, depending on the film thickness of the insulating film 125A and the film thicknesses of the mask layers 118B, 118G, and 118R, the first etching process may be stopped before the insulating film 125A is processed into the insulating layer 125. Specifically, the first etching process may be stopped after only thinning a portion of the insulating film 125A. Furthermore, if the insulating film 125A is formed using the same material as the mask layers 118B, 118G, and 118R, the boundary between the insulating film 125A and the mask layers 118B, 118G, and 118R may become unclear, making it impossible to determine whether the insulating layer 125 has been formed, or whether the film thickness of the mask layers 118B, 118G, and 118R has been thinned.

[0387] Furthermore, Figure 18D shows an example where the shape of the insulating layer 127b is unchanged from that in Figure 18C, but the present invention is not limited to this. For example, the edge of the insulating layer 127b may droop and cover the edge of the insulating layer 125. Also, for example, the edge of the insulating layer 127b may come into contact with the upper surface of the mask layers 118B, 118G, and 118R. As mentioned above, if the insulating layer 127b is not exposed after development, the shape of the insulating layer 127b may change easily.

[0388] Next, post-baking is performed. As shown in Figure 18E, post-baking can deform the insulating layer 127b into an insulating layer 127 having a tapered shape on its sides. As mentioned above, the shape of the insulating layer 127b may have already changed and acquired a tapered shape on its sides by the time the first etching process is completed.

[0389] In the first etching process, by not completely removing the mask layers 118B, 118G, and 118R, and leaving them in a thinned state, it is possible to prevent damage and degradation of layers 113G, 113G, and 113R during the heat treatment. Therefore, the reliability of the light-emitting device can be improved.

[0390] Next, as shown in Figure 18F, etching is performed using the insulating layer 127 as a mask to remove a portion of the mask layers 118B, 118G, and 118R. This creates openings in the mask layers 118B, 118G, and 118R, exposing the upper surfaces of layers 113G, 113G, 113R, and the conductive layer 123. In the following, the etching process using the insulating layer 127 as a mask may be referred to as the second etching process.

[0391] The edges of the insulating layer 125 are covered with the insulating layer 127. Figure 18F also shows an example where the insulating layer 127 covers a portion of the edge of the mask layer 118G (specifically, the tapered portion formed by the first etching process), while the tapered portion formed by the second etching process is exposed. In other words, this corresponds to the structure shown in Figures 2A and 2B.

[0392] As described above, by using a method that performs etching before and after post-bake, even if the insulating layer 125 and the mask layer are side-etched and voids are created in the first etching process, the insulating layer 127 can fill these voids by performing post-bake afterward. Subsequently, in the second etching process, the mask layer, which has become thinner, is etched, so the amount of side etching is reduced, making it less likely for voids to form, and even if voids do form, they can be made extremely small. As a result, the surfaces forming the common layer 114 and the common electrode 115 can be made flatter.

[0393] Furthermore, as shown in Figures 3A and 5B, the insulating layer 127 may cover the entire edge of the mask layer 118G. For example, the edge of the insulating layer 127 may droop and cover the edge of the mask layer 118G. Also, for example, the edge of the insulating layer 127 may be in contact with at least one upper surface of layer 113B, layer 113G, and layer 113R. As mentioned above, if the insulating layer 127b is not exposed after development, the shape of the insulating layer 127 may change easily.

[0394] The second etching process is preferably performed by wet etching. By using the wet etching method, damage to layers 113B, 113G, and 113R can be reduced compared to when using the dry etching method. Wet etching can be performed using an alkaline solution or the like.

[0395] Furthermore, there may be limitations on the equipment and methods that can be used for etching the insulating film 125A. For example, since the first etching process described above is performed before post-bake, it is preferable to perform the etching of the insulating film 125A using a paddle method with a developing apparatus and developing solution. This allows the insulating film 125A to be processed without adding any new equipment other than the equipment used for exposure, development, and post-bake. For example, when an aluminum oxide film is used as the insulating film 125A, the insulating film 125A can be processed by wet etching using a developing solution containing TMAH.

[0396] Here, wet etching is preferably performed using a method that consumes little etching solution, for example, the paddle method is preferred. Note that the etching area of ​​the insulating film 125A in the connection part 140 is much larger than the etching area of ​​the insulating film 125A in the display part. For example, in the paddle method, the supply of etchant becomes the limiting factor in the connection part 140, and the etching rate tends to be lower than that of the display part. If there is a difference in etching rate between the display part and the connection part 140 in this way, there is a problem in that the processing of the insulating film 125A cannot be performed stably. For example, if the etching time is set according to the etching rate in the connection part 140, there is a risk that the insulating film 125A in the display part will be over-etched. Also, if the etching time is set according to the etching rate in the display part, there is a risk that the insulating film 125A in the connection part 140 will not be sufficiently etched and will remain. On the other hand, if a method that constantly supplies new solution to avoid a difference in etching rate (for example, the spin method) consumes a lot of etching solution.

[0397] Therefore, the exposure and development of the insulating film 127a may be performed separately at the connection section 140 and the display section. This allows the etching conditions (etching time, etc.) of the insulating film 125A to be controlled independently at the connection section 140 and the display section, thereby suppressing both excessive etching of the insulating film 125A at the display section and insufficient etching of the insulating film 125A at the connection section 140, and enabling the insulating film 125A to be processed into the desired shape.

[0398] Next, the process for the exposure and development of the insulating film 127a, when performed separately in the display unit and the connection unit 140, will be explained using Figures 19A to 19C.

[0399] After forming the insulating film 127a (Figure 17B), exposure is performed at the connection portion 140 (Figure 19A). Specifically, using a mask 132a, visible light or ultraviolet light is irradiated onto the region of the insulating film 127a that overlaps with the conductive layer 123, thereby exposing a portion of the insulating film 127a.

[0400] Next, development is performed to remove the exposed areas of the insulating film 127a. As a result, the insulating film 127a is formed over the entire display area and in the area surrounding the conductive layer 123 (Figure 19B).

[0401] The development method is not particularly limited, and dip method, spin method, paddle method, vibration method, etc., can be used. In order to stabilize the etching rate, it is preferable to apply a method that constantly supplies new solution. Alternatively, it is preferable to apply a method that repeatedly supplies and holds (develops) the solution (also called the step-paddle method). The step-paddle method is preferable because it can save on solution consumption and stabilize the etching rate compared to the method that constantly supplies new solution.

[0402] Next, etching is performed using the insulating film 127a as a mask to remove a portion of the insulating film 125A in the connection portion 140 and to thin a portion of the mask layer 118B. In the connection portion 140, the surface of the portion of the mask layer 118B with a thin film thickness is exposed (Figure 19B).

[0403] As for the etching process, the method that can be used for the first etching process described above can be applied.

[0404] In the etching process for the connection portion 140, the mask layer 118B is not completely removed, and the etching process is stopped when the film thickness is reduced. The mask layer 118B at the connection portion 140 is also processed in the etching process described later. If the mask layer 118B is completely removed in the etching process at this stage, in subsequent etching processes, the insulating film 125A and the mask layer beneath the edge of the insulating layer 127 may disappear due to side etching, and a cavity may be formed. In this way, by leaving the mask layer 118B on the conductive layer 123, it is possible to prevent the mask layer 118B from being excessively etched and the conductive layer 123 from being damaged in subsequent processes.

[0405] Furthermore, depending on the film thickness of the insulating film 125A and the mask layer 118B, the etching process may be stopped after only thinning a portion of the insulating film 125A. Also, if the insulating film 125A is deposited using the same material as the mask layer 118B, the boundary between the insulating film 125A and the mask layer 118B may become unclear, making it impossible to determine whether the insulating film 125A has been removed or remains in a thin film, or whether the film thickness of the mask layer 118B has been thinned.

[0406] Next, exposure is performed on the display unit (Figure 19B). Specifically, using the mask 132b, visible light or ultraviolet light is irradiated onto the region of the insulating film 127a that overlaps with the pixel electrode 111R, the region that overlaps with the pixel electrode 111G, and the region that overlaps with the pixel electrode 111B, thereby exposing a portion of the insulating film 127a.

[0407] Next, development is performed to remove the exposed area of ​​the insulating film 127a and form the insulating layer 127b (Figure 19C). The insulating layer 127b is formed in the region sandwiched between any two of the pixel electrodes 111R, 111G, and 111B, and in the region surrounding the conductive layer 123.

[0408] Next, as shown in Figure 19C, etching is performed using the insulating layer 127b as a mask to remove a portion of the insulating film 125A and thin the film thickness of parts of the mask layers 118B, 118G, and 118R. As a result, the insulating layer 125 is formed beneath the insulating layer 127b. In addition, the surfaces of the thinned portions of the mask layers 118B, 118G, and 118R are exposed.

[0409] The etching process shown in Figure 19C is the same as the first etching process shown in Figure 18D. Furthermore, the etching method can be the same as that used for the first etching process described above.

[0410] Note that at the point shown in Figure 19C, the mask layer 118B at the connection point 140 may be completely removed, exposing the conductive layer 123.

[0411] Subsequently, the insulating layer 125 and the insulating layer 127 can be formed by performing the aforementioned post-bake and second etching processes.

[0412] As described above, by performing the exposure and development of the film that will become the insulating layer 127 separately in the display unit and the connection unit 140, the processing conditions for the film that will become the insulating layer 125 can be independently controlled in the display unit and the connection unit 140. This makes it possible to process the insulating layer 125 into the desired shape and reduces manufacturing defects in the display device.

[0413] Furthermore, depending on the etching apparatus and method, the difference in etching rates between the connection portion 140 and the display portion can sometimes be made sufficiently small. Also, depending on the layout of the connection portion 140 and the insulating layer 127b, the difference between the etching area of ​​the insulating film 125A in the connection portion 140 and the etching area of ​​the insulating film 125A in the display portion can sometimes be made sufficiently small. In such cases, as shown in Figures 17C and 18A, it is preferable to perform the exposure and development of the insulating film 127a in the same process for both the display portion and the connection portion 140. This reduces the number of processes.

[0414] Next, a common layer 114 and a common electrode 115 are formed in this order on the insulating layer 127, layer 113B, layer 113G, and layer 113R (Figure 20A), and then a protective layer 131 is formed (Figure 20B). Then, the substrate 120 is bonded onto the protective layer 131 using the resin layer 122 to fabricate the display device (Figure 1B).

[0415] The common layer 114 can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0416] 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.

[0417] Methods for forming the protective layer 131 include vacuum deposition, sputtering, CVD, and ALD.

[0418] As described above, in the method for manufacturing the display device of this embodiment, the island-shaped layers 113B, 113G, and 113R are formed not using a fine metal mask, but by processing after a film is deposited on one surface, so that the island-shaped layers can be formed with a uniform thickness. This makes it possible to realize a high-resolution display device or a display device with a high aperture ratio. Furthermore, even if the resolution or aperture ratio is high and the distance between subpixels is extremely short, it is possible to suppress contact between layers 113B, 113G, and 113R in adjacent subpixels. Therefore, it is possible to suppress the generation of leakage current between subpixels. This makes it possible to prevent crosstalk caused by unintended light emission and realize a display device with extremely high contrast.

[0419] Furthermore, in the method for manufacturing the display device of this embodiment, after forming an island-like layer having a light-emitting material that emits blue light, an island-like layer having a light-emitting material that emits light with a longer wavelength than blue is formed. This suppresses the increase in driving voltage and the decrease in lifespan of the blue light-emitting device. In addition, high brightness emission can be achieved with the light-emitting devices of each color. Furthermore, the increase in driving voltage of the light-emitting devices of each color can be suppressed. In addition, the lifespan of the light-emitting devices of each color can be extended, and the reliability of the display device can be improved.

[0420] Furthermore, by providing an insulating layer 127 having a tapered shape at its end between adjacent island-shaped EL layers, it is possible to suppress the occurrence of step breaks when forming the common electrode 115, and to prevent the formation of locally thin areas in the common electrode 115. As a result, connection failures caused by the divided areas and increases in electrical resistance caused by locally thin areas can be suppressed in the common layer 114 and the common electrode 115. Therefore, a display device according to one aspect of the present invention can achieve both high resolution and high display quality.

[0421] This embodiment can be combined with other embodiments as appropriate.

[0422] (Embodiment 3) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 21 and 22.

[0423] [Pixel layout] This embodiment primarily describes a pixel layout different from that shown in 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.

[0424] In this embodiment, the top surface shape of the subpixel shown in the figure corresponds to the top surface shape of the light-emitting region (or light-receiving region).

[0425] The top surface shape of the subpixel may include, for example, polygons such as triangles, quadrilaterals (including rectangles and squares), pentagons, polygons with rounded corners, ellipses, or circles.

[0426] Furthermore, the circuit layout constituting the sub-pixel is not limited to the sub-pixel range shown in the figure, but may be arranged outside of it.

[0427] The pixel 110 shown in Figure 21A has an S-stripe array applied to it. The pixel 110 shown in Figure 21A is composed of three subpixels: subpixels 110a, 110b, and 110c.

[0428] The pixel 110 shown in Figure 21B includes sub-pixels 110a with a roughly triangular or trapezoidal top surface shape with rounded corners, sub-pixels 110b with a roughly triangular or trapezoidal top surface shape with rounded corners, and sub-pixels 110c with a roughly square or hexagonal top surface shape with rounded corners. Furthermore, sub-pixel 110b has a larger light-emitting area than sub-pixel 110a. In this way, the shape and size of each sub-pixel can be determined independently. For example, sub-pixels with more reliable light-emitting devices can be made smaller in size.

[0429] A Pentile array is applied to pixels 124a and 124b shown in Figure 21C. Figure 21C shows an example in which pixels 124a having sub-pixels 110a and 110b, and pixels 124b having sub-pixels 110b and 110c are arranged alternately.

[0430] Pixels 124a and 124b, shown in Figures 21D to 21F, have a delta array applied. 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).

[0431] Figure 21D shows an example where each subpixel has a roughly square top shape with rounded corners, Figure 21E shows an example where each subpixel has a circular top shape, and Figure 21F shows an example where each subpixel has a roughly hexagonal top shape with rounded corners.

[0432] In Figure 21F, each subpixel is located inside a densely packed hexagonal region. When focusing on one subpixel, it is arranged so that it is surrounded by six other subpixels. Furthermore, subpixels that emit light of the same color are not adjacent to each other. For example, when focusing on subpixel 110a, three subpixels 110b and three subpixels 110c are arranged alternately around it.

[0433] Figure 21G 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.

[0434] In each pixel shown in Figures 21A to 21G, it is preferable, for example, that sub-pixel 110a be sub-pixel R that emits red light, sub-pixel 110b be sub-pixel G that emits green light, and sub-pixel 110c be sub-pixel B that emits blue light. However, the configuration of the sub-pixels is not limited to this, and the colors emitted by the sub-pixels and their order can be determined as appropriate. For example, sub-pixel 110b may be sub-pixel R that emits red light, and sub-pixel 110a may be sub-pixel G that emits green light.

[0435] 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.

[0436] 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.

[0437] 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.

[0438] As shown in Figures 22A to 22I, a pixel can be configured to have four types of subpixels.

[0439] The pixels 110 shown in Figures 22A to 22C have a stripe arrangement applied to them.

[0440] Figure 22A shows an example where each subpixel has a rectangular top surface shape, Figure 22B shows an example where each subpixel has a top surface shape formed by connecting two semicircles and a rectangle, and Figure 22C shows an example where each subpixel has an elliptical top surface shape.

[0441] The pixels 110 shown in Figures 22D to 22F have a matrix array applied to them.

[0442] Figure 22D shows an example where each subpixel has a square top surface shape, Figure 22E shows an example where each subpixel has a roughly square top surface shape with rounded corners, and Figure 22F shows an example where each subpixel has a circular top surface shape.

[0443] Figures 22G and 22H show an example where one pixel 110 is composed of 2 rows and 3 columns.

[0444] Pixel 110, shown in Figure 22G, 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.

[0445] As shown in Figure 22H, 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 22H, by aligning the arrangement of subpixels in the top row and 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.

[0446] Figure 22I shows an example where one pixel 110 is composed of 3 rows and 2 columns.

[0447] Pixel 110, shown in Figure 22I, has a sub-pixel 110a in the top row (1st row), a sub-pixel 110b in the middle row (2nd row), a sub-pixel 110c spanning from the 1st to the 2nd row, and one sub-pixel (sub-pixel 110d) in the bottom row (3rd row). In other words, pixel 110 has sub-pixels 110a and 110b in the left column (1st column), a sub-pixel 110c in the right column (2nd column), and a sub-pixel 110d spanning these two columns.

[0448] The pixel 110 shown in Figures 22A to 22I is composed of four subpixels: subpixels 110a, 110b, 110c, and 110d.

[0449] The sub-pixels 110a, 110b, 110c, and 110d can each be configured to have a light-emitting device that emits light of a different color. Examples of sub-pixels 110a, 110b, 110c, and 110d include sub-pixels of four colors: R, G, B, and white (W); sub-pixels of four colors: R, G, B, and Y; or sub-pixels of R, G, B, and infrared (IR).

[0450] In each pixel 110 shown in Figures 22A to 22I, it is preferable, for example, that sub-pixel 110a be sub-pixel R that emits red light, sub-pixel 110b be sub-pixel G that emits green light, sub-pixel 110c be sub-pixel B that emits blue light, and sub-pixel 110d be sub-pixel W that emits white light, sub-pixel Y that emits yellow light, or sub-pixel IR that emits near-infrared light. With such a configuration, in the pixels 110 shown in Figures 22G and 22H, the layout of R, G, and B becomes a stripe arrangement, which can improve the display quality. Also, in the pixels 110 shown in Figure 22I, the layout of R, G, and B becomes a so-called S-stripe arrangement, which can improve the display quality.

[0451] Furthermore, the pixel 110 may have subpixels that have a light-receiving device.

[0452] In each pixel 110 shown in Figures 22A to 22I, one of the sub-pixels 110a to 110d may be a sub-pixel having a light-receiving device.

[0453] In each pixel 110 shown in Figures 22A to 22I, it is preferable, for example, that sub-pixel 110a be a sub-pixel R that emits red light, sub-pixel 110b be a sub-pixel G that emits green light, sub-pixel 110c be a sub-pixel B that emits blue light, and sub-pixel 110d be a sub-pixel S having a light-receiving device. With such a configuration, in the pixels 110 shown in Figures 22G and 22H, the layout of R, G, and B becomes a stripe arrangement, which can improve the display quality. Also, in the pixels 110 shown in Figure 22I, the layout of R, G, and B becomes a so-called S-stripe arrangement, which can improve the display quality.

[0454] The wavelength of light detected by the sub-pixel S, which has a light-receiving device, is not particularly limited. The sub-pixel S can be configured to detect either visible light or infrared light, or both.

[0455] As shown in Figures 22J and 22K, a pixel can be configured to have five types of subpixels.

[0456] Figure 22J shows an example where one pixel 110 is composed of 2 rows and 3 columns.

[0457] Pixel 110, shown in Figure 22J, has three subpixels (subpixels 110a, 110b, and 110c) in the top row (1st row) and two subpixels (subpixels 110d and 110e) in the bottom row (2nd row). In other words, pixel 110 has subpixels 110a and 110d in the left column (1st column), subpixel 110b in the middle column (2nd column), subpixel 110c in the right column (3rd column), and subpixel 110e extending from the 2nd to the 3rd column.

[0458] Figure 22K shows an example where one pixel 110 is composed of 3 rows and 2 columns.

[0459] Pixel 110, shown in Figure 22K, has subpixel 110a in the top row (1st row), subpixel 110b in the middle row (2nd row), subpixel 110c spanning from the 1st to the 2nd row, and two subpixels (subpixels 110d and 110e) in the bottom row (3rd row). In other words, pixel 110 has subpixels 110a, 110b, and 110d in the left column (1st column), and subpixels 110c and 110e in the right column (2nd column).

[0460] In each pixel 110 shown in Figures 22J and 22K, it is preferable, for example, that sub-pixel 110a be sub-pixel R that emits red light, sub-pixel 110b be sub-pixel G that emits green light, and sub-pixel 110c be sub-pixel B that emits blue light. With such a configuration, in the pixel 110 shown in Figure 22J, the layout of R, G, and B becomes a stripe arrangement, which can improve the display quality. Also, in the pixel 110 shown in Figure 22K, the layout of R, G, and B becomes a so-called S-stripe arrangement, which can improve the display quality.

[0461] Furthermore, in each pixel 110 shown in Figures 22J and 22K, it is preferable to apply a sub-pixel S having a photodetector to at least one of the sub-pixels 110d and 110e. When photodetectors are used for both sub-pixels 110d and 110e, the configurations of the photodetectors may differ from each other. For example, the wavelength ranges of light detected by each may differ in some respects. Specifically, one of the sub-pixels 110d and 110e may have a photodetector that mainly detects visible light, while the other may have a photodetector that mainly detects infrared light.

[0462] Furthermore, in each pixel 110 shown in Figures 22J and 22K, it is preferable to apply a sub-pixel S having a light-receiving device to one of the sub-pixels 110d and 110e, and a sub-pixel having a light-emitting device that can be used as a light source to the other. For example, it is preferable that one of the sub-pixels 110d and 110e is a sub-pixel IR that emits infrared light, and the other is a sub-pixel S having a light-receiving device that detects infrared light.

[0463] In pixels having sub-pixels R, G, B, IR, and S, an image can be displayed using sub-pixels R, G, and B, while sub-pixel IR is used as a light source to detect the reflected infrared light emitted by sub-pixel S.

[0464] As described above, in one aspect of the present invention, a display device can be configured to have pixels having subpixels with light-emitting devices, and various layouts can be applied to these pixels. Furthermore, in one aspect of the present invention, a display device can be configured to have pixels having both light-emitting devices and light-receiving devices. In this case as well, various layouts can be applied.

[0465] This embodiment can be combined with other embodiments as appropriate.

[0466] (Embodiment 4) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 23 to 33.

[0467] The display device of this embodiment can be a high-definition display device. Therefore, the display device of this embodiment can be used, for example, as a display unit for information terminals (wearable devices) such as wristwatches and bracelets, and as a display unit for wearable devices that can be worn on the head, such as VR devices such as head-mounted displays (HMDs) and AR devices such as glasses.

[0468] Furthermore, 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 equipment, 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.

[0469] [Display Module] Figure 23A shows a perspective view of the display module 280. The display module 280 includes a display device 100A and an FPC 290. Note that the display device included in the display module 280 is not limited to display device 100A, but may be any of the display devices 100B to 100F described later.

[0470] 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.

[0471] Figure 23B 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.

[0472] The pixel section 284 has a plurality of pixels 284a arranged periodically. A magnified view of one pixel 284a is shown on the right side of Figure 23B. Various configurations described in the previous embodiment can be applied to the pixel 284a. Figure 23B shows an example where the pixel has a configuration similar to that of the pixel 110 shown in Figure 1A.

[0473] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0474] A single pixel circuit 283a is a circuit that controls the driving of multiple elements in a single pixel 284a. A single pixel circuit 283a can be configured to have three circuits that control the light emission of a single light-emitting device. For example, a single pixel circuit 283a can be configured to have at least one selection transistor, one current control transistor (driving transistor), and a capacitor 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.

[0475] 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.

[0476] 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.

[0477] 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.

[0478] Because such a display module 280 is extremely high-resolution, it can be suitably used in VR devices such as HMDs or AR devices such as glasses. 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, and a highly immersive display can be achieved. 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 watches.

[0479] [Display device 100A] The display device 100A shown in Figure 24A includes a substrate 301, light-emitting devices 130R, 130G, 130B, a capacitor 240, and a transistor 310.

[0480] Substrate 301 corresponds to substrate 291 in Figures 23A and 23B. The laminated structure from substrate 301 to insulating layer 255c corresponds to layer 101 containing the transistor in Embodiment 1.

[0481] 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.

[0482] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0483] Furthermore, an insulating layer 261 is provided covering the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0484] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located between them. The conductive layer 241 acts as one electrode of the capacitor 240, the conductive layer 245 acts as the other electrode of the capacitor 240, and the insulating layer 243 acts as the dielectric of the capacitor 240.

[0485] 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.

[0486] Furthermore, it is preferable to provide a conductive layer surrounding the outside of the display unit 281 (or pixel unit 284) in at least one of the conductive layer layers of the layer 101 containing the transistor. This conductive layer can also be called a guard ring. By providing this conductive layer, it is possible to suppress the application of high voltage to elements such as transistors and light-emitting devices due to charging by ESD (electrostatic discharge) or plasma-based processes, which could cause these elements to be destroyed.

[0487] An insulating layer 255a is provided covering the capacitance 240, an insulating layer 255b is provided on the insulating layer 255a, and an insulating layer 255c is provided on the insulating layer 255b. Light-emitting devices 130R, 130G, and 130B are provided on the insulating layer 255c. Figure 24A shows an example in which light-emitting devices 130R, 130G, and 130B have the same structure as the laminated structure shown in Figure 1B. An insulator is provided in the region between adjacent light-emitting devices. In Figure 24A and other figures, an insulating layer 125 and an insulating layer 127 on the insulating layer 125 are provided in this region.

[0488] A mask layer 118R is located on layer 113R of light-emitting device 130R, a mask layer 118G is located on layer 113G of light-emitting device 130G, and a mask layer 118B is located on layer 113B of light-emitting device 130B.

[0489] Pixel electrodes 111R, 111G, and 111B are electrically connected to either the source or drain of transistor 310 by plugs 256 embedded in insulating layers 243, 255a, 255b, and 255c, 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 255c and the height of the upper surface of plug 256 are equal or approximately equal. Various conductive materials can be used for the plugs. Figure 24A, etc., shows an example in which the pixel electrode has a two-layer structure consisting of a reflective electrode and a transparent electrode on the reflective electrode.

[0490] Furthermore, a protective layer 131 is provided on the light-emitting devices 130R, 130G, and 130B. 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 23A.

[0491] The display device shown in Figures 24B and 24C is an example having light-emitting devices 130R and 130G, and a light-receiving device 150. Although not shown, the display device also has a light-emitting device 130B. In Figures 24B and 24C, the layers below the insulating layer 255a are omitted. The display device shown in Figures 24B and 24C can be configured using any of the transistor-containing layer 101 configurations shown in Figures 24A and 25 to 29.

[0492] The light-receiving device 150 comprises a pixel electrode 111S, a layer 113S, a common layer 114, and a common electrode 115, all stacked together. For details of the display device having the light-receiving device, refer to Embodiments 1 and 6.

[0493] As shown in Figure 24C, the display device may be provided with a lens array 133. The lens array 133 can be superimposed on one or both of the light-emitting device and the light-receiving device.

[0494] Figure 24C shows an example in which a lens array 133 is provided on the light-emitting devices 130R, 130G, and the light-receiving device 150 via a protective layer 131. By directly forming the lens array 133 on the substrate on which the light-emitting devices (and light-receiving devices) are formed, the accuracy of the alignment between the light-emitting device or light-receiving device and the lens array can be improved.

[0495] In Figure 24C, the light emitted from the light-emitting device passes through the lens array 133 and is extracted to the outside of the display device.

[0496] Alternatively, a lens array 133 may be provided on the substrate 120 and bonded to the protective layer 131 with a resin layer 122. By providing the lens array 133 on the substrate 120, the temperature of the heat treatment in the lens array 133 formation process can be increased.

[0497] [Display device 100B] The display device 100B shown in Figure 25 has a configuration in which transistors 310A and 310B, each with a channel formed on a semiconductor substrate, are stacked. In the following description of the display device, parts that are the same as those described earlier may be omitted.

[0498] The display device 100B has a configuration in which a substrate 301B on which a transistor 310B, a capacitor 240, and a light-emitting device are provided, and a substrate 301A on which a transistor 310A is provided are bonded together.

[0499] 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 described later can be used.

[0500] 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. An inorganic insulating film, usable for the protective layer 131, can be used as the insulating layer 344.

[0501] 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.

[0502] 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.

[0503] 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.

[0504] 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).

[0505] [Display device 100C] The display device 100C shown in Figure 26 has a configuration in which conductive layer 341 and conductive layer 342 are joined via bumps 347.

[0506] As shown in Figure 26, 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 including, 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.

[0507] [Display device 100D] The display device 100D shown in Figure 27 differs from the display device 100A mainly in its transistor configuration.

[0508] 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.

[0509] 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.

[0510] Substrate 331 corresponds to substrate 291 in Figures 23A and 23B. The laminated structure from substrate 331 to insulating layer 255c corresponds to layer 101 containing the transistor in Embodiment 1. An insulating substrate or a semiconductor substrate can be used as substrate 331.

[0511] 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.

[0512] 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.

[0513] 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. A pair of conductive layers 325 are provided in contact with the semiconductor layer 321 and function as a source electrode and a drain electrode.

[0514] An insulating layer 328 is provided covering the top and side surfaces of a 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. An insulating film similar to that used for the insulating layer 332 can be used for the insulating layer 328.

[0515] 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.

[0516] 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.

[0517] 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.

[0518] 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.

[0519] [Display device 100E] The display device 100E shown in Figure 28 has a configuration in which transistors 320A and 320B, each having an oxide semiconductor in the semiconductor on which the channel is formed, are stacked.

[0520] For details regarding transistors 320A and 320B, and their peripheral configurations, please refer to the display device 100D described above.

[0521] In this example, we have used a configuration in which two transistors having oxide semiconductors are stacked, but this is not the only option. For example, a configuration in which three or more transistors are stacked may also be used.

[0522] [Display device 100F] The display device 100F shown in Figure 29 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.

[0523] 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.

[0524] 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.

[0525] 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.

[0526] [Display device 100G] Figure 30 shows a perspective view of the display device 100G, and Figure 31A shows a cross-sectional view of the display device 100G.

[0527] The display device 100G has a configuration in which substrate 152 and substrate 151 are bonded together. In Figure 30, substrate 152 is shown with a dashed line.

[0528] The display device 100G includes a display unit 162, a connection unit 140, a circuit 164, wiring 165, etc. Figure 30 shows an example in which IC 173 and FPC 172 are mounted on the display device 100G. Therefore, the configuration shown in Figure 30 can also be described as a display module having the display device 100G, an IC (integrated circuit), and an FPC.

[0529] 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 30 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.

[0530] For example, a scan line drive circuit can be used as circuit 164.

[0531] The 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 the wiring 165 from an external source via the FPC 172, or from the IC 173.

[0532] Figure 30 shows an example in which IC 173 is provided 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 100G 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.

[0533] Figure 31A shows an example of a cross-section of the display device 100G 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.

[0534] The display device 100G shown in Figure 31A includes a transistor 201, a transistor 205, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, and a light-emitting device 130B that emits blue light, etc., between substrates 151 and 152.

[0535] The light-emitting devices 130R, 130G, and 130B 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.

[0536] The light-emitting device 130R has a conductive layer 112R, a conductive layer 126R on the conductive layer 112R, and a conductive layer 129R on the conductive layer 126R. All of the conductive layers 112R, 126R, and 129R can be called pixel electrodes, or only a part of them can be called pixel electrodes.

[0537] The light-emitting device 130G includes a conductive layer 112G, a conductive layer 126G on the conductive layer 112G, and a conductive layer 129G on the conductive layer 126G.

[0538] The light-emitting device 130B includes a conductive layer 112B, a conductive layer 126B on the conductive layer 112B, and a conductive layer 129B on the conductive layer 126B.

[0539] The conductive layer 112R 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 126R is located outside the edge of the conductive layer 112R. The edges of the conductive layer 126R and the conductive layer 129R are aligned or approximately aligned. For example, conductive layers that function as reflective electrodes can be used for conductive layers 112R and 126R, and a conductive layer that functions as a transparent electrode can be used for conductive layer 129R.

[0540] The conductive layers 112G, 126G, and 129G in the light-emitting device 130G, and the conductive layers 112B, 126B, and 129B in the light-emitting device 130B, are the same as the conductive layers 112R, 126R, and 129R in the light-emitting device 130R, so a detailed explanation is omitted.

[0541] The conductive layers 112R, 112G, and 112B are formed to cover the openings provided in the insulating layer 214. Layer 128 is embedded in the recesses of the conductive layers 112R, 112G, and 112B.

[0542] Layer 128 has the function of flattening the recesses of the conductive layers 112R, 112G, and 112B. Conductive layers 126R, 126G, and 126B are provided on conductive layers 112R, 112G, and 112B and on layer 128, and are electrically connected to conductive layers 112R, 112G, and 112B. Therefore, regions overlapping with the recesses of conductive layers 112R, 112G, and 112B can also be used as light-emitting regions, thereby increasing the aperture ratio of the pixels.

[0543] 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, and especially preferable that it be formed using an organic insulating material. For example, an organic insulating material that can be used for the insulating layer 127 described above can be applied to layer 128.

[0544] The top and side surfaces of conductive layers 126R and 129R are covered by layer 113R. Similarly, the top and side surfaces of conductive layers 126G and 129G are covered by layer 113G, and the top and side surfaces of conductive layers 126B and 129B are covered by layer 113B. Therefore, the entire region where conductive layers 126R, 126G, and 126B are provided can be used as the light-emitting region of light-emitting devices 130R, 130G, and 130B, thereby increasing the aperture ratio of the pixels.

[0545] The upper surfaces and sides of layers 113B, 113G, and 113R are covered by insulating layers 125 and 127. A mask layer 118B is located between layer 113B and insulating layer 125. A mask layer 118G is located between layer 113G and insulating layer 125, and a mask layer 118R is located between layer 113R and insulating layer 125. A common layer 114 is provided on layers 113B, 113G, 113R, and insulating layers 125 and 127, and a common electrode 115 is provided on the common layer 114. The common layer 114 and the common electrode 115 are each a continuous film provided in common to multiple light-emitting devices.

[0546] Furthermore, a protective layer 131 is provided on the light-emitting devices 130R, 130G, and 130B. The protective layer 131 and the substrate 152 are bonded via an adhesive layer 142. A light-shielding layer 117 is provided on the substrate 152. For sealing the light-emitting devices, a solid sealing structure or a hollow sealing structure can be applied. In Figure 31A, the space between the substrate 152 and the substrate 151 is filled with the adhesive layer 142, and a solid sealing structure is applied. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), and a hollow sealing structure may be applied. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting devices. Also, the space may be filled with a resin different from the adhesive layer 142, which is provided in a frame shape.

[0547] The protective layer 131 is provided at least on the display unit 162, and preferably so as to cover the entire display unit 162. It is preferable that the protective layer 131 covers not only the display unit 162, but also the connection unit 140 and the circuit 164. Furthermore, it is preferable that the protective layer 131 extends to the edges of the display device 100G. On the other hand, in the connection unit 204, there is a portion where the protective layer 131 is not provided in order to electrically connect the FPC 172 and the conductive layer 166.

[0548] 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 112R, 112G, and 112B, a conductive film obtained by processing the same conductive film as conductive layers 126R, 126G, and 126B, and a conductive film obtained by processing the same conductive film as conductive layers 129R, 129G, and 129B. On the upper surface of the connection portion 204, the conductive layer 166 is exposed. This allows the connection portion 204 and FPC 172 to be electrically connected via the connection layer 242.

[0549] For example, after the protective layer 131 is deposited on the entire surface of the display device 100G, the conductive layer 166 can be exposed by removing the area of ​​the protective layer 131 that overlaps with the conductive layer 166 using a mask.

[0550] Alternatively, a laminated structure of at least one organic layer and a conductive layer may be provided on the conductive layer 166, and a protective layer 131 may be provided on the laminated structure. Then, a starting point for peeling (a part that triggers peeling) may be formed on the laminated structure using a laser or a sharp blade (e.g., a needle or cutter), and the laminated structure and the protective layer 131 on it may be selectively removed, exposing the conductive layer 166. For example, the protective layer 131 can be selectively removed by pressing an adhesive roller against the substrate 151 and moving the roller relatively while rotating it. Alternatively, an adhesive tape may be attached to the substrate 151 and peeled off. Due to the low adhesion between the organic layer and the conductive layer, or between the organic layers themselves, separation occurs at the interface between the organic layer and the conductive layer, or within the organic layer. This allows for the selective removal of the area of ​​the protective layer 131 that overlaps with the conductive layer 166. If any organic layers remain on the conductive layer 166, they can be removed with an organic solvent or the like.

[0551] As the organic layer, for example, at least one organic layer (a layer that functions as a light-emitting layer, a carrier block layer, a carrier transport layer, or a carrier implantation layer) can be used in any of layers 113B, 113G, and 113R. The organic layer may be formed simultaneously with the deposition of any of layers 113B, 113G, and 113R, or it may be provided separately. The conductive layer can be formed using the same process and materials as the common electrode 115. For example, it is preferable to form an ITO film as both the common electrode 115 and the conductive layer. When a laminated structure is used for the common electrode 115, at least one layer from among the layers constituting the common electrode 115 is provided as the conductive layer.

[0552] Furthermore, the upper surface of the conductive layer 166 may be covered with a mask to prevent the protective layer 131 from being formed on the conductive layer 166. As the mask, for example, a metal mask (area metal mask) may be used, or an adhesive or suction tape or film may be used. By forming the protective layer 131 with the mask in place and then removing the mask, the conductive layer 166 can be kept exposed even after the protective layer 131 has been formed.

[0553] Using this method, a region of the connection portion 204 is formed where the protective layer 131 is not provided, and in that region, the conductive layer 166 and the FPC 172 can be electrically connected via the connecting layer 242.

[0554] 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 112R, 112G, and 112B, a conductive film obtained by processing the same conductive film as conductive layers 126R, 126G, and 126B, and a conductive film obtained by processing the same conductive film as conductive layers 129R, 129G, and 129B. The ends of the conductive layer 123 are covered by a mask layer 118B, an insulating layer 125, and an insulating layer 127. A common layer 114 is provided on the conductive layer 123, and a common electrode 115 is provided on the common layer 114. The conductive layer 123 and the common electrode 115 are electrically connected via the common layer 114. Note that the common 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.

[0555] The display device 100G 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.

[0556] The laminated structure from the substrate 151 to the insulating layer 214 corresponds to the layer 101 containing the transistor in Embodiment 1.

[0557] Both transistors 201 and 205 are formed on the substrate 151. These transistors can be manufactured using the same materials and the same process.

[0558] 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.

[0559] 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.

[0560] 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.

[0561] An organic insulating layer is preferred for the insulating layer 214, which functions as a planarizing layer. Examples of materials that can be used for the organic insulating layer 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 layer and an inorganic insulating layer. The outermost layer of the insulating layer 214 preferably functions as an etching protection layer. This makes it possible to suppress the formation of depressions in the insulating layer 214 when processing conductive layers 112R, 126R, or 129R. Alternatively, depressions may be provided in the insulating layer 214 when processing conductive layers 112R, 126R, or 129R.

[0562] 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.

[0563] 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.

[0564] 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.

[0565] 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.

[0566] 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.

[0567] Examples of crystalline oxide semiconductors include CAAC (c-axis-aligned crystalline)-OS and nc (nanocrystalline)-OS.

[0568] Alternatively, a transistor using silicon as the channel-forming region (Si transistor) may be used. Examples of silicon include single-crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, a transistor having low-temperature polysilicon (LTPS (Low Temperature Poly Silicon)) in the semiconductor layer (hereinafter also referred to as an LTPS transistor) can be used. LTPS transistors have high field-effect mobility and good frequency characteristics.

[0569] By using Si 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.

[0570] OS transistors have extremely high field-effect mobility compared to transistors using amorphous silicon. Furthermore, OS transistors exhibit remarkably low source-drain leakage current (also called off-current) in the off state, allowing them to retain charge stored in a capacitor connected in series with the transistor for extended periods. Additionally, the application of OS transistors can reduce the power consumption of display devices.

[0571] Furthermore, to increase the luminescence brightness of the light-emitting device included in the pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting device. To achieve this, it is necessary to increase the source-drain voltage of the drive transistor included in the pixel circuit. Compared to Si transistors, OS transistors have a higher breakdown voltage between the source and drain, so a higher voltage can be applied between the source and drain of an OS transistor. Therefore, by using an OS transistor as the drive transistor included in the pixel circuit, the amount of current flowing through the light-emitting device can be increased, thereby increasing the luminescence brightness of the light-emitting device.

[0572] Furthermore, when the transistor operates in the saturation region, OS transistors exhibit smaller changes in source-drain current in response to changes in gate-source voltage compared to Si transistors. Therefore, by using OS transistors as driving transistors in the pixel circuit, the current flowing between the source and drain can be precisely controlled by changes in gate-source voltage, thereby allowing control of the amount of current flowing to the light-emitting device. This allows for an increase in the number of gradation elements in the pixel circuit.

[0573] Furthermore, in terms of the saturation characteristics of the current flowing when a transistor operates in the saturation region, OS transistors can supply a more stable current (saturation current) than Si transistors, even when the source-drain voltage gradually increases. Therefore, by using OS transistors as driving transistors, a stable current can be supplied to the light-emitting device even if there are variations in the current-voltage characteristics of the EL device. In other words, when operating in the saturation region, the source-drain current remains almost unchanged even when the source-drain voltage is increased, thus stabilizing the luminescence brightness of the light-emitting device.

[0574] As described above, by using OS transistors in the drive transistors included in the pixel circuit, it is possible to achieve "suppression of black level floating," "increase in luminescence brightness," "multi-gradation," and "suppression of variations in light-emitting devices."

[0575] The metal oxide used in 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.

[0576] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also written as IGZO) 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. Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), and zinc (Zn) (also written as IAZO). Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), gallium (Ga), and zinc (Zn) (also written as IAGZO).

[0577] 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 greater than or equal to the atomic ratio of M. Possible atomic ratios of metal elements in such an In-M-Zn oxide include: In:M:Zn=1:1:1 or near that composition, In:M:Zn=1:1:1.2 or near that composition, In:M:Zn=1:3:2 or near that composition, In:M:Zn=1:3:4 or near that composition, In:M:Zn=2:1:3 or near that composition, In:M:Zn=3:1:2 or near that composition, and In:M:Zn=4:2:3 Examples include compositions near the desired atomic ratio, such as In:M:Zn=4:2:4.1 or near that ratio, In:M:Zn=5:1:3 or near that ratio, In:M:Zn=5:1:6 or near that ratio, In:M:Zn=5:1:7 or near that ratio, In:M:Zn=5:1:8 or near that ratio, In:M:Zn=6:1:6 or near that ratio, In:M:Zn=5:2:5 or near that ratio, etc. Note that "nearby composition" includes a range of ±30% of the desired atomic ratio.

[0578] 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.

[0579] 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.

[0580] All of the transistors in the display unit 162 may be OS transistors, all of the transistors in the display unit 162 may be Si transistors, or some of the transistors in the display unit 162 may be OS transistors and the rest may be Si transistors.

[0581] For example, by using both LTPS transistors and OS transistors in the display unit 162, 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. In a more preferable example, it is preferable to apply OS transistors to transistors that function as switches for controlling conduction and non-conduction between wiring, and LTPS transistors to transistors that control current.

[0582] For example, one of the transistors in the display unit 162 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.

[0583] On the other hand, the other transistor in the display unit 162 functions as a switch for controlling 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.

[0584] Thus, a display device according to one aspect of the present invention can combine a high aperture ratio, high resolution, high display quality, and low power consumption.

[0585] Furthermore, one embodiment of the present invention is a display device having an OS transistor and a light-emitting device with an MML (metal maskless) structure. This configuration makes it possible to extremely reduce the leakage current that can flow through the transistor and the leakage current that can flow between adjacent light-emitting devices (also called lateral leakage current or side leakage current). With this configuration, when an image is displayed on the display device, the observer can observe one or more of the following: image sharpness, image clarity, high saturation, and high contrast ratio. Moreover, by having an extremely low leakage current that can flow through the transistor and lateral leakage current between light-emitting devices, it is possible to achieve a display with as little light leakage (so-called black floating) that may occur when displaying black as possible.

[0586] In particular, even among MML-structured light-emitting devices, applying the aforementioned SBS structure results in a configuration where the layers between light-emitting devices (for example, an organic layer used in common between light-emitting devices, also called a common layer) are separated, thus eliminating or significantly reducing side leakage.

[0587] Figures 31B and 31C show other examples of transistor configurations.

[0588] 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.

[0589] In the transistor 209 shown in Figure 31B, 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.

[0590] On the other hand, in the transistor 210 shown in Figure 31C, 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 31C can be fabricated by processing the insulating layer 225 using the conductive layer 223 as a mask. In Figure 31C, 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.

[0591] 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. In addition, various optical components can be arranged on the outside of the substrate 152.

[0592] Materials that can be used for substrate 120 can be applied to substrate 151 and substrate 152, respectively.

[0593] As the adhesive layer 142, a material that can be used for the resin layer 122 can be applied.

[0594] As the connecting layer 242, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), etc., can be used.

[0595] [Display device 100H] The display device 100H shown in Figure 32A differs from the display device 100G mainly in that it is a bottom-emission type display device.

[0596] 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.

[0597] 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 32A 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.

[0598] The light-emitting device 130R includes a conductive layer 112R, a conductive layer 126R on the conductive layer 112R, and a conductive layer 129R on the conductive layer 126R.

[0599] The light-emitting device 130G includes a conductive layer 112G, a conductive layer 126G on the conductive layer 112G, and a conductive layer 129G on the conductive layer 126G.

[0600] The conductive layers 112R, 112G, 126R, 126G, 129R, and 129G are made of materials with high transmittance to visible light. It is preferable to use a material that reflects visible light for the common electrode 115.

[0601] Furthermore, while Figures 31A and 32A show examples where the upper surface of layer 128 has a flat portion, the shape of layer 128 is not particularly limited. Figures 32B to 32D show modified examples of layer 128.

[0602] As shown in Figures 32B and 32D, 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.

[0603] Furthermore, as shown in Figure 32C, 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.

[0604] 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.

[0605] Furthermore, the height of the top surface of layer 128 and the height of the top surface of the conductive layer 112R 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 112R.

[0606] Furthermore, Figure 32B can be seen as an example in which layer 128 is housed inside a recess in the conductive layer 112R. On the other hand, as shown in Figure 32D, layer 128 may exist outside the recess of the conductive layer 112R, that is, the width of the upper surface of layer 128 may be wider than that of the recess.

[0607] [Display device 100J] The display device 100J shown in Figure 33 differs from the display device 100G mainly in that it has a light receiving device 150.

[0608] The light-receiving device 150 includes a conductive layer 112S, a conductive layer 126S on the conductive layer 112S, and a conductive layer 129S on the conductive layer 126S.

[0609] The conductive layer 112S is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214.

[0610] The top and side surfaces of conductive layer 126S and conductive layer 129S are covered by layer 113S. Layer 113S has at least an active layer.

[0611] A portion of the upper surface and sides of layer 113S are covered by insulating layers 125 and 127. A mask layer 118S is located between layer 113S and insulating layer 125. A common layer 114 is provided on layer 113S and insulating layers 125 and 127, and a common electrode 115 is provided on the common layer 114. The common layer 114 is a continuous film provided in common to both the light-receiving device and the light-emitting device.

[0612] The display device 100J can, for example, apply the pixel layout shown in Figures 22A to 22K, as described in Embodiment 3. For details of the display device having a light-receiving device, refer to Embodiments 1 and 6.

[0613] This embodiment can be combined with other embodiments as appropriate.

[0614] (Embodiment 5) This embodiment describes a light-emitting device that can be used in a display device according to one aspect of the present invention.

[0615] As shown in Figure 34A, the light-emitting device has an EL layer 763 between a pair of electrodes (lower electrode 761 and upper electrode 762). The EL layer 763 can be composed of multiple layers, such as layer 780, light-emitting layer 771, and layer 790.

[0616] The light-emitting layer 771 has at least a light-emitting substance (also called a light-emitting material).

[0617] When the lower electrode 761 is the anode and the upper electrode 762 is the cathode, layer 780 has one or more of the following: a layer containing a material with high hole injection properties (hole injection layer), a layer containing a material with high hole transport properties (hole transport layer), and a layer containing a material with high electron blocking properties (electron blocking layer). Similarly, layer 790 has one or more of the following: a layer containing a material with high electron injection properties (electron injection layer), a layer containing a material with high electron transport properties (electron transport layer), and a layer containing a material with high hole blocking properties (hole blocking layer). When the lower electrode 761 is the cathode and the upper electrode 762 is the anode, layers 780 and 790 have the opposite configurations to those described above.

[0618] A configuration having a layer 780, an emissive layer 771, and a layer 790 provided between a pair of electrodes can function as a single emissive unit, and in this specification, the configuration shown in Figure 34A is referred to as a single structure.

[0619] Furthermore, Figure 34B shows a modified example of the EL layer 763 of the light-emitting device shown in Figure 34A. Specifically, the light-emitting device shown in Figure 34B has a layer 781 on the lower electrode 761, a layer 782 on the layer 781, a light-emitting layer 771 on the layer 782, a layer 791 on the light-emitting layer 771, a layer 792 on the layer 791, and an upper electrode 762 on the layer 792.

[0620] When the lower electrode 761 is the anode and the upper electrode 762 is the cathode, for example, layer 781 can be a hole injection layer, layer 782 a hole transport layer, layer 791 an electron transport layer, and layer 792 an electron injection layer. Also, when the lower electrode 761 is the cathode and the upper electrode 762 is the anode, layer 781 can be an electron injection layer, layer 782 an electron transport layer, layer 791 a hole transport layer, and layer 792 a hole injection layer. By using such a layer structure, carriers can be efficiently injected into the light-emitting layer 771, and the efficiency of carrier recombination within the light-emitting layer 771 can be increased.

[0621] As shown in Figures 34C and 34D, a configuration in which multiple light-emitting layers (light-emitting layers 771, 772, and 773) are provided between layer 780 and layer 790 is also a variation of the single structure. Although Figures 34C and 34D show an example with three light-emitting layers, the light-emitting layers in a single-structure light-emitting device may be two or four or more. Furthermore, a single-structure light-emitting device may have a buffer layer between the two light-emitting layers. The buffer layer can be formed using, for example, a material that can be used for a hole transport layer or an electron transport layer.

[0622] Furthermore, as shown in Figures 34E and 34F, a configuration in which multiple light-emitting units (light-emitting units 763a and 763b) are connected in series via a charge generation layer 785 (also called an intermediate layer) is referred to as a tandem structure in this specification. The tandem structure may also be called a stacked structure. By using a tandem structure, a light-emitting device capable of high-brightness emission can be created. In addition, compared to a single structure, the tandem structure can reduce the current required to obtain the same brightness, thereby improving reliability.

[0623] Figures 34D and 34F show examples in which the display device has a layer 764 that overlaps with the light-emitting device. Figure 34D shows an example in which layer 764 overlaps with the light-emitting device shown in Figure 34C, and Figure 34F shows an example in which layer 764 overlaps with the light-emitting device shown in Figure 34E. In Figures 34D and 34F, a conductive film that transmits visible light is used for the upper electrode 762 in order to extract light to the upper electrode 762 side.

[0624] Layer 764 can be either a color conversion layer or a color filter (coloring layer), or both.

[0625] In Figures 34C and 34D, the light-emitting layers 771, 772, and 773 may be made of light-emitting materials that emit light of the same color, or even the same light-emitting material. For example, light-emitting materials that emit blue light may be used for the light-emitting layers 771, 772, and 773. In subpixels that emit blue light, the blue light emitted by the light-emitting device can be extracted. In subpixels that emit red light and subpixels that emit green light, a color conversion layer is provided as layer 764 as shown in Figure 34D, which converts the blue light emitted by the light-emitting device into longer wavelength light, allowing for the extraction of red or green light.

[0626] Furthermore, light-emitting materials that emit light of different colors may be used for each of the light-emitting layers 771, 772, and 773. When the light emitted by each of the light-emitting layers 771, 772, and 773 is complementary in color, white light emission is obtained. For example, a single-structure light-emitting device preferably has a light-emitting layer having a light-emitting material that emits blue light, and a light-emitting layer having a light-emitting material that emits visible light with a longer wavelength than blue.

[0627] For example, if a single-structure light-emitting device has three light-emitting layers, it is preferable that it has a light-emitting layer having a light-emitting material that emits red (R) light, a light-emitting layer having a light-emitting material that emits green (G) light, and a light-emitting layer having a light-emitting material that emits blue (B) light. The stacking order of the light-emitting layers can be R, G, B from the anode side, or R, B, G from the anode side, etc. In this case, a buffer layer may be provided between R and G or B.

[0628] Furthermore, for example, if a single-structure light-emitting device has two light-emitting layers, it is preferable that one light-emitting layer has a light-emitting material that emits blue light, and the other light-emitting layer has a light-emitting material that emits yellow light.

[0629] A color filter may be provided as layer 764, as shown in Figure 34D. By passing white light through the color filter, light of the desired color can be obtained.

[0630] A light-emitting device that emits white light preferably contains two or more types of light-emitting materials. To obtain white light emission, one should select light-emitting materials such that the light emitted by each of the two or more materials is complementary in color. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary, a light-emitting device that emits white light as a whole can be obtained. The same applies to light-emitting devices that have three or more light-emitting layers.

[0631] Furthermore, in Figures 34E and 34F, the light-emitting layer 771 and the light-emitting layer 772 may be made of light-emitting materials that emit light of the same color, or even the same light-emitting material.

[0632] For example, in a light-emitting device having subpixels that emit light of each color, a light-emitting material that emits blue light may be used in the light-emitting layer 771 and the light-emitting layer 772. In the subpixel that emits blue light, the blue light emitted by the light-emitting device can be extracted. In addition, in the subpixel that emits red light and the subpixel that emits green light, by providing a color conversion layer as layer 764 as shown in Figure 34F, the blue light emitted by the light-emitting device can be converted into longer wavelength light, and red or green light can be extracted.

[0633] Furthermore, when using light-emitting devices with the configuration shown in Figure 34E or Figure 34F for sub-pixels that emit light of each color, different light-emitting materials may be used for each sub-pixel. Specifically, in a light-emitting device for a sub-pixel that emits red light, light-emitting materials that emit red light may be used for both the light-emitting layer 771 and the light-emitting layer 772. Similarly, in a light-emitting device for a sub-pixel that emits green light, light-emitting materials that emit green light may be used for both the light-emitting layer 771 and the light-emitting layer 772. In a light-emitting device for a sub-pixel that emits blue light, light-emitting materials that emit blue light may be used for both the light-emitting layer 771 and the light-emitting layer 772. A display device with such a configuration can be said to have a tandem structure light-emitting device and an SBS structure. Therefore, it can combine the advantages of both the tandem structure and the SBS structure. This enables high-brightness light emission and realizes a highly reliable light-emitting device.

[0634] Furthermore, in Figures 34E and 34F, luminescent materials emitting light of different colors may be used for the luminescent layer 771 and the luminescent layer 772. When the light emitted by the luminescent layer 771 and the light emitted by the luminescent layer 772 are complementary colors, white light emission is obtained. A color filter may be provided as layer 764 as shown in Figure 34F. By passing white light through the color filter, light of a desired color can be obtained.

[0635] In Figures 34E and 34F, examples are shown in which the light-emitting unit 763a has one light-emitting layer 771 and the light-emitting unit 763b has one light-emitting layer 772, but the design is not limited to this. The light-emitting unit 763a and the light-emitting unit 763b may each have two or more light-emitting layers.

[0636] Furthermore, while Figures 34E and 34F illustrate a light-emitting device having two light-emitting units, the device is not limited to this. A light-emitting device may have three or more light-emitting units.

[0637] Specifically, when using a tand...

Claims

1. A first pixel electrode and a second pixel electrode are formed. A first film is formed on the first pixel electrode and the second pixel electrode. A first mask film is formed on the first film. The first film and the first mask film are processed to form a first layer and a first mask layer on the first pixel electrode, and the second pixel electrode is exposed. A second film is formed on the first mask layer and the second pixel electrode. A second mask film is formed on the second film. The second film and the second mask film are processed to form a second layer and a second mask layer on the second pixel electrode, and the first mask layer is exposed. A first insulating film is formed on the first mask layer and the second mask layer. A second insulating film is formed on the first insulating film. The second insulating film is processed to form a second insulating layer that overlaps with the region sandwiched between the first pixel electrode and the second pixel electrode. The second insulating layer is used as a mask to perform an etching process, thereby processing the first insulating film, the first mask layer, and the second mask layer to expose the upper surfaces of the first layer and the second layer. A common electrode is formed by covering the first layer, the second layer, and the second insulating layer. The first layer has a first light-emitting material that emits blue light, A method for manufacturing a display device, wherein the second layer has a second light-emitting material that emits light with a longer wavelength than blue light.

2. A first pixel electrode and a second pixel electrode are formed. A first film is formed on the first pixel electrode and the second pixel electrode. A first mask film is formed on the first film. The first film and the first mask film are processed to form a first layer and a first mask layer on the first pixel electrode, and the second pixel electrode is exposed. A second film is formed on the first mask layer and the second pixel electrode. A second mask film is formed on the second film. The second film and the second mask film are processed to form a second layer and a second mask layer on the second pixel electrode, and the first mask layer is exposed. A first insulating film is formed on the first mask layer and the second mask layer. A second insulating film is formed on the first insulating film. The second insulating film is processed to form a second insulating layer that overlaps with the region sandwiched between the first pixel electrode and the second pixel electrode. The second insulating layer is used as a mask to perform the first etching process, thereby removing a portion of the first insulating film and thinning the film thickness of a portion of the first mask layer and a portion of the second mask layer. A heat treatment is performed, and then a second etching treatment is performed using the second insulating layer as a mask to remove a portion of the first mask layer and a portion of the second mask layer, exposing the upper surface of the first layer and the upper surface of the second layer. A common electrode is formed by covering the first layer, the second layer, and the second insulating layer. The first layer has a first light-emitting material that emits blue light, A method for manufacturing a display device, wherein the second layer has a second light-emitting material that emits light with a longer wavelength than blue light.

3. A first pixel electrode, a second pixel electrode, and a first conductive layer are formed. A first film is formed on the first pixel electrode and the second pixel electrode. A first mask film is formed on the first film and the first conductive layer. The first film and the first mask film are processed to form a first layer and a first mask layer on the first pixel electrode, a second mask layer is formed on the first conductive layer, and the second pixel electrode is exposed. A second film is formed on the first mask layer and the second pixel electrode. A second mask film is formed on the second film. The second film and the second mask film are processed to form a second layer and a third mask layer on the second pixel electrode, and the first mask layer and the second mask layer are exposed. A first insulating film is formed on the first to third mask layers. A second insulating film is formed on the first insulating film using a photosensitive resin composition. By exposing and developing the second insulating film, the portion of the first insulating film that overlaps with the second mask layer is exposed. The first etching process is performed using the second insulating film as a mask to remove the portion of the first insulating film that overlaps with the second mask layer, and to thin a portion of the second mask layer. By exposing and developing the second insulating film, the portion of the first insulating film that overlaps with the first mask layer and the portion that overlaps with the third mask layer are exposed, and a second insulating layer is formed that overlaps with the region sandwiched between the first pixel electrode and the second pixel electrode. Using the second insulating layer as a mask, a second etching process is performed to remove the portion of the first insulating film that overlaps with the first mask layer and the portion that overlaps with the third mask layer, thereby forming a first insulating layer that overlaps with the second insulating layer, and thinning the film thickness of a portion of the first mask layer and a portion of the third mask layer. A heat treatment is performed, and then a third etching treatment is performed using the second insulating layer as a mask to remove a portion of the first mask layer and a portion of the third mask layer, exposing the upper surface of the first layer and the upper surface of the second layer. A common electrode is formed by covering the first layer, the second layer, the first conductive layer, and the second insulating layer. By the second etching process or the third etching process, a portion of the second mask layer is removed, exposing the upper surface of the first conductive layer. The first layer has a first light-emitting material that emits blue light, A method for manufacturing a display device, wherein the second layer has a second light-emitting material that emits light with a longer wavelength than blue light.

4. In claim 2 or 3, A method for manufacturing a display device, wherein the first etching process and the second etching process are performed by wet etching.

5. In any one of claims 1 to 3, The first layer comprises a first light-emitting layer and a first functional layer on the first light-emitting layer. The second layer comprises a second light-emitting layer and a second functional layer on the second light-emitting layer. The first light-emitting layer comprises the first light-emitting material, The second light-emitting layer comprises the second light-emitting material, A method for manufacturing a display device, wherein the first functional layer and the second functional layer each have at least one of the following: a hole injection layer, an electron injection layer, a hole transport layer, an electron transport layer, a hole blocking layer, and an electron blocking layer.

6. In any one of claims 1 to 3, As the first insulating film, an aluminum oxide film is formed using the ALD method. A method for manufacturing a display device, comprising forming aluminum oxide films as the first and second mask films using the ALD method.

7. In any one of claims 1 to 3, A method for manufacturing a display device, wherein the second insulating film is formed using a photosensitive acrylic resin.

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