Display devices, display modules and electronic devices

Abstract

A display device with high display quality is provided. The display unit includes a first sub-pixel, the first sub-pixel includes a first light-emitting device and a first color layer that transmits blue light, the first light-emitting device includes a first pixel electrode, a first EL layer and a common electrode, the first EL layer includes a first light-emitting material that emits blue light and a second light-emitting material that emits light with a longer wavelength than blue, the first EL layer includes a first light-emitting unit on the first pixel electrode, a charge-generating layer on the first light-emitting unit and a second light-emitting unit on the charge-generating layer, when the intensity of the first emission peak in the wavelength range of 400 nm to 500 nm in the emission spectrum when the display unit displays blue light at low brightness is set to 1, the intensity of the second emission peak in the wavelength range of 500 nm to 700 nm in the emission spectrum is 0.5 or less.

Description

[Technical Field]

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

[0002] Note that one embodiment of the present invention is not limited to the above-described technical field. As an example of the technical field of one embodiment of the present invention, examples include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting equipment, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), and driving or manufacturing methods of the above devices. [Previous Technology]

[0003] In recent years, display devices have been expected to be used for various purposes. For example, as large display devices, examples include home televisions (also known as televisions or television receivers), digital signage, and public information displays (PIDs). In addition, as portable information terminals, smartphones and tablets with touch panels are under development.

[0004] In addition, there is a demand for high-definition display devices. As devices that require high-definition display devices, the development of devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR) is very active.

[0005] As a display device, for example, a light-emitting device including a light-emitting device (also called a light-emitting element) is being developed. Light-emitting devices (also called "EL devices" or "EL elements") that utilize the electroluminescence (hereinafter referred to as EL) phenomenon have the characteristics of being easy to achieve in thin and lightweight form; being able to respond to input signals at high speed; and being able to be driven by a DC constant voltage power supply, etc., and have been applied to display devices.

[0006] Patent document 1 discloses a VR-oriented display device using an organic EL device (also known as an organic EL element).

[0007] [Patent Document 1] International Patent Application Publication No. 2018 / 087625 [Summary of the Invention]

[0008] Due to the structure of certain display devices, color shifts sometimes occur between low-brightness and high-brightness displays. Furthermore, crosstalk sometimes occurs (current flows to adjacent sub-pixels, resulting in unintended light emission) when the display device is made high-resolution. Therefore, one object of an embodiment of the present invention is to provide a display device with high display quality. Another object of an embodiment of the present invention is to provide a display device with minimal color variation between low-brightness and high-brightness displays.

[0009] Furthermore, one objective of an embodiment of the present invention is to provide a high-definition display device. Another objective of an embodiment of the present invention is to provide a high-resolution display device. A third objective of an embodiment of the present invention is to provide a highly reliable display device.

[0010] One objective of one embodiment of the present invention is to provide a method for manufacturing a high-definition display device. Another objective of one embodiment of the present invention is to provide a method for manufacturing a high-resolution display device. Another objective of one embodiment of the present invention is to provide a method for manufacturing a display device with high reliability. Another objective of one embodiment of the present invention is to provide a method for manufacturing a display device with high yield.

[0011] Note that the description of these objectives does not preclude the existence of other objectives. One embodiment of the present invention does not need to achieve all of the above objectives. Objectives other than those described above can be extracted from the description, drawings, and claims.

[0012] One embodiment of the present invention is a display device, comprising: a display unit capable of full-color display, wherein the display unit includes a first sub-pixel, the first sub-pixel includes a first light-emitting device and a first color layer that transmits blue light, the first light-emitting device includes a first pixel electrode, a first EL layer on the first pixel electrode and a common electrode on the first EL layer, the first EL layer includes a first light-emitting material that emits blue light and a second light-emitting material that emits light with a longer wavelength than blue, the first EL layer includes a first light-emitting unit on the first pixel electrode, a charge-generating layer on the first light-emitting unit and a second light-emitting unit on the charge-generating layer, wherein when the intensity of the first emission peak in the wavelength range of 400 nm or more and less than 500 nm in the emission spectrum when the display unit displays blue at a first brightness is set to 1, the intensity of the second emission peak in the wavelength range of 500 nm or more and less than 700 nm in the emission spectrum is 0.5 or less, and the first brightness is any value in the range of 0 cd / m2 or more and less than 1 cd / m2.

[0013] The display unit preferably further includes a second sub-pixel, which includes a second light-emitting device and a second color layer that transmits light of a different color than the first color layer. The second light-emitting device preferably includes a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer. The first EL layer and the second EL layer preferably have the same structure. The first EL layer and the second EL layer are preferably separated from each other.

[0014] In addition, one embodiment of the present invention is a display device, including: a display unit capable of full-color display, wherein the display unit includes a first sub-pixel and a second sub-pixel, the first sub-pixel includes a first light-emitting device and a first color layer that transmits blue light, the second sub-pixel includes a second light-emitting device and a second color layer that transmits light of a different color than the first color layer, the first light-emitting device includes a first pixel electrode, a first EL layer on the first pixel electrode and a common electrode on the first EL layer, the second light-emitting device includes a second pixel electrode, a first EL layer on the second pixel electrode and a common electrode on the first EL layer, the first EL layer includes a first light-emitting unit on the first pixel electrode, a charge-generating layer on the first light-emitting unit and a second light-emitting unit on the charge-generating layer, wherein when the intensity of the first emission peak in the wavelength range of 400 nm or more and less than 500 nm in the emission spectrum when the display unit displays blue at a first brightness is set to 1, the intensity of the second emission peak in the wavelength range of 500 nm or more and less than 700 nm in the emission spectrum is 0.5 or less, and the first brightness is any value in the range of 0 cd / m2 or more and less than 1 cd / m2.

[0015] One embodiment of the present invention is a display device, comprising: a display unit capable of full-color display, wherein the display unit includes a first sub-pixel and a second sub-pixel, the first sub-pixel includes a first light-emitting device and a first color layer that transmits blue light, the second sub-pixel includes a second light-emitting device and a second color layer that transmits light of a different color than the first color layer, the first light-emitting device includes a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer, the second light-emitting device includes a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer, the first EL layer and The second EL layer has the same structure, and the first EL layer and the second EL layer are separated from each other. The first EL layer includes a first light-emitting unit on the first pixel electrode, a charge generation layer on the first light-emitting unit, and a second light-emitting unit on the charge generation layer. When the intensity of the first light-emitting peak in the wavelength range of 400 nm to 500 nm in the emission spectrum when the display unit is displayed in blue at a first brightness is set to 1, the intensity of the second light-emitting peak in the wavelength range of 500 nm to 700 nm in the emission spectrum is 0.5 or less, and the first brightness is any value in the range of 0 cd / m2 to 1 cd / m2.

[0016] Preferably, the first light-emitting device includes a common layer between the first EL layer and the common electrode, and the second light-emitting device preferably includes a common layer between the second EL layer and the common electrode, and the common layer includes at least one of a hole injection layer, a hole transport layer, a hole barrier layer, an electron barrier layer, an electron transport layer and an electron injection layer.

[0017] The display unit preferably includes a first insulating layer, which preferably covers the side surface of the first EL layer and the side surface of the second EL layer, and the common electrode is preferably located on the first insulating layer. Furthermore, the first insulating layer preferably contacts the side surface of the first pixel electrode and the side surface of the second pixel electrode.

[0018] Preferably, the display section includes a second insulating layer, the first insulating layer includes an inorganic material, and the second insulating layer includes an organic material and covers the side surface of the first EL layer and the side surface of the second EL layer through the first insulating layer.

[0019] The resolution of the display is preferably 1000ppi or higher, 2000ppi or higher, 3000ppi or higher, 5000ppi or higher, or 6000ppi or higher and 20000ppi or lower or 30000ppi or lower.

[0020] The first sub-pixel preferably includes a lens that overlaps with the first light-emitting device and the first color layer.

[0021] The first pixel electrode is preferably made of a material that reflects visible light.

[0022] Preferably, the first sub-pixel includes a reflective layer, the first pixel electrode includes a material that transmits visible light, and the first pixel electrode is located between the reflective layer and the first EL layer.

[0023] One embodiment of the present invention is a display module including a display device having any of the above structures. The display module is a display module with a connector such as a flexible printed circuit (FPC) or a TCP (tape carrier package), or a display module with an integrated circuit (IC) mounted using COG (Chip On Glass) or COF (Chip On Film) methods.

[0024] One embodiment of the present invention is an electronic device comprising: the above-described display module; and at least one of a housing, a battery, a camera, a speaker, and a microphone.

[0025] According to one embodiment of the present invention, a display device with high display quality can be provided. According to one embodiment of the present invention, a display device with minimal color variation between low-brightness and high-brightness displays can be provided. According to one embodiment of the present invention, a high-definition display device can be provided. According to one embodiment of the present invention, a high-resolution display device can be provided. According to one embodiment of the present invention, a display device with high reliability can be provided.

[0026] According to one embodiment of the present invention, a method for manufacturing a high-definition display device can be provided. According to one embodiment of the present invention, a method for manufacturing a high-resolution display device can be provided. According to one embodiment of the present invention, a method for manufacturing a display device with high reliability can be provided. According to one embodiment of the present invention, a method for manufacturing a display device with high yield can be provided.

[0027] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not require all of the above-described effects. Effects other than those described above can be extracted from the description in the specification, drawings, and claims.

Implementation Method

[0029] The embodiments will be described in detail with reference to the drawings. Note that the present invention is not limited to the following description, and those skilled in the art will readily understand that its methods and details can be varied in many ways without departing from the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited only to the contents described in the embodiments shown below.

[0030] Note that in the structure of the invention described below, the same element symbols are used in common across different figures to represent the same parts or parts having the same function, and repeated descriptions are omitted. Furthermore, when representing parts having the same function, the same shading lines are sometimes used without additional element symbols.

[0031] In addition, for ease of understanding, the positions, sizes, and ranges of the components shown in the drawings do not necessarily represent their actual positions, sizes, and ranges. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and ranges disclosed in the drawings.

[0032] In addition, depending on the situation or state, the "film" and "layer" can be interchanged. For example, the "conductive layer" can be changed into the "conductive film". Furthermore, the "insulating film" can be changed into the "insulating layer".

[0033] In this specification, etc., devices manufactured using a metal mask or FMM (Fine Metal Mask) are sometimes referred to as devices having an FMM structure or devices having an MM (Metal Mask) structure. Furthermore, in this specification, etc., devices manufactured without a metal mask or FMM are sometimes referred to as devices having an MML (Metal Mask Less) structure.

[0034] Embodiment 1 In this embodiment, a display device and its manufacturing method according to an embodiment of the present invention will be described using Figures 1 to 11.

[0035] One embodiment of the present invention is a display device including a display section capable of full-color display. The display section includes sub-pixels that emit blue light, each equipped with a light-emitting device and a color layer that transmits blue light. The light-emitting device includes a pixel electrode, an EL layer on the pixel electrode, and a common electrode on the EL layer. The EL layer includes a light-emitting material that emits blue light and a light-emitting material that emits light with a wavelength longer than blue. Furthermore, the EL layer includes a first light-emitting unit on the pixel electrode, a charge-generating layer on the first light-emitting unit, and a second light-emitting unit on the charge-generating layer. In other words, in the display device of one embodiment of the present invention, a light-emitting device employing a series structure including multiple light-emitting units is used. Furthermore, the display section capable of full-color display includes at least two types of sub-pixels: those emitting blue light and those emitting light other than blue. Examples of blue light include light with a peak wavelength of 400 nm or more and less than 500 nm.

[0036] In a display device according to one embodiment of the present invention, when the intensity of the first emission peak in the wavelength range of 400 nm or more and less than 500 nm in the emission spectrum when the display unit is displayed in blue at a first brightness is set to 1, the intensity of the second emission peak in the wavelength range of 500 nm or more and less than 700 nm in the emission spectrum is 0 or more and 0.5 or less, and the first brightness is any value in the range of more than 0 cd / m2 and less than 1 cd / m2. In other words, the display device according to one embodiment of the present invention mainly observes blue light when displaying in blue at low brightness and it is difficult to observe light with wavelengths longer than blue (including cases where it is not substantially observable).

[0037] In light-emitting devices with a single structure (a structure with only one light-emitting unit) having multiple light-emitting layers, adjusting the carrier balance is difficult, and sometimes the emitted color changes between low-brightness and high-brightness emission. On the other hand, compared with single-structure light-emitting devices, light-emitting devices with a series structure are easier to adjust the carrier balance and the emitted color does not easily change between low-brightness and high-brightness emission. Therefore, a display device according to one embodiment of the present invention can achieve high display quality with less color change between low-brightness and high-brightness display.

[0038] Furthermore, in a display device according to one embodiment of the present invention, each sub-pixel includes a light-emitting device having an EL layer with the same structure and a color layer overlapping the light-emitting device. By providing a color layer that transmits visible light of different colors for each sub-pixel, full-color display can be performed.

[0039] When a light-emitting device including an EL layer with the same structure is used in each sub-pixel, it is not necessary to separately coat the light-emitting layer of each of the multiple sub-pixels. Therefore, multiple sub-pixels can share (share) a layer other than the pixel electrode included in the light-emitting device (e.g., a light-emitting layer). However, there are layers with high conductivity included in the light-emitting device. When multiple sub-pixels share a layer with high conductivity, leakage current sometimes occurs between the sub-pixels. In particular, when the display device is made more detailed or has a higher aperture ratio and the distance between sub-pixels becomes smaller, there is a concern that the leakage current becomes larger and cannot be ignored, leading to a decrease in the display quality of the display device. Therefore, in a display device according to one embodiment of the present invention, at least a portion of the layer constituting the EL layer in each sub-pixel is formed as an island. By separating at least a portion of the layer constituting the EL layer for each sub-pixel, crosstalk between adjacent sub-pixels can be suppressed. Thus, both high definition and high display quality of the display device can be achieved simultaneously.

[0040] For example, island-shaped light-emitting layers can be deposited using vacuum evaporation with a metal mask (also known as a shadow mask). However, in this method, various factors such as the precision of the metal mask, the misalignment between the metal mask and the substrate, the bending of the metal mask, and the enlargement of the outline of the deposited film caused by vapor scattering result in the shape and position of the island-shaped light-emitting layer deviating from the design, making it difficult to achieve high resolution and high aperture ratio in the display device. In addition, during evaporation, the thickness at the ends sometimes decreases due to the blurring of the layer outline. That is, the thickness of the island-shaped light-emitting layer sometimes varies depending on the position. Furthermore, when manufacturing large and high-resolution or high-definition display devices, there are concerns such as a decrease in manufacturing yield due to low dimensional accuracy of the metal mask and deformation caused by heat.

[0041] Therefore, in manufacturing a display device according to one embodiment of the present invention, a pixel electrode is formed for each sub-pixel, and then a light-emitting layer is deposited across multiple pixel electrodes. Then, for example, the light-emitting layer is processed using photolithography to form an island-shaped light-emitting layer on one pixel electrode. Thus, the light-emitting layer is divided according to each sub-pixel, and an island-shaped light-emitting layer can be formed for each sub-pixel.

[0042] Thus, the island-shaped light-emitting layer manufactured by the display device manufacturing method according to one embodiment of the present invention is not formed using a metal mask including a highly fine pattern, but is formed by depositing the light-emitting layer on the entire surface and then processing it. Specifically, the size of the island-shaped light-emitting layer is a size that is miniaturized by segmentation using photolithography or the like. Therefore, the size of the island-shaped light-emitting layer can be made smaller than the size formed using a metal mask. Therefore, it is possible to realize a high-definition display device or a display device with a high aperture ratio that has been difficult to achieve until now.

[0043] Note that when the number of processing steps for the light-emitting layer using photolithography is small, manufacturing costs can be reduced and manufacturing yield can be increased, which is preferable. In a method for manufacturing a display device according to one embodiment of the present invention, the number of processing steps for the light-emitting layer using photolithography can be set to once, so the display device can be manufactured with high yield.

[0044] Regarding the spacing between adjacent light-emitting devices, it is difficult to achieve a spacing of less than 10 μm in methods using metal masks, but the above-described method can reduce this spacing to less than 10 μm, less than 5 μm, less than 3 μm, less than 2 μm, or less than 1 μm. Furthermore, for example, by using an LSI exposure apparatus, the spacing between adjacent light-emitting devices can be reduced to less than 500 nm, less than 200 nm, less than 100 nm, or even less than 50 nm. This significantly reduces the area of ​​the non-light-emitting region that can exist between two light-emitting devices, allowing the aperture ratio to approach 100%. For example, aperture ratios of 50% or more, 60% or more, 70% or more, 80% or more, or even 90% or more but less than 100% can be achieved.

[0045] Furthermore, the pattern (also known as the processing size) of the light-emitting layer itself can be extremely small compared to the case where a metal mask is used. Moreover, for example, when forming the light-emitting layer separately using a metal mask, the effective area usable as a light-emitting region in the overall area of ​​the light-emitting layer becomes smaller due to thickness inhomogeneities at the center and ends of the light-emitting layer. On the other hand, in the above manufacturing method, a film deposited with uniform thickness is processed, so island-shaped light-emitting layers can be formed with uniform thickness. Therefore, even using a fine pattern, almost the entire area of ​​the light-emitting layer can be used as a light-emitting region. Therefore, a display device with both high resolution and high aperture ratio can be manufactured.

[0046] Furthermore, in a method for manufacturing a display device according to one embodiment of the present invention, it is preferable to form a layer including a light-emitting layer (also referred to as an EL layer or a part of an EL layer) on one surface, and then form a sacrificial layer (also referred to as a mask layer) on the EL layer. Furthermore, it is preferable to form a photoresist mask on the sacrificial layer and process the EL layer and the sacrificial layer using the photoresist mask, thereby forming an island-shaped EL layer.

[0047] By setting a sacrificial layer on the EL layer, the damage to the EL layer during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-emitting device.

[0048] The island-shaped EL layer includes at least a light-emitting layer, and the island-shaped EL layer is preferably composed of multiple layers. Specifically, it is preferable to include one or more layers on the light-emitting layer. By including other layers between the light-emitting layer and the sacrificial layer, the exposure of the light-emitting layer to the outermost surface during the manufacturing process of the display device can be suppressed, and damage to the light-emitting layer can be reduced. As a result, the reliability of the light-emitting device can be improved. Therefore, each island-shaped EL layer preferably includes a light-emitting layer and a carrier transport layer (electron transport layer or hole transport layer) on the light-emitting layer.

[0049] Furthermore, in a light-emitting device, it is not necessary to process all layers constituting the EL layer into island shapes; some layers can be arranged in a manner shared by multiple light-emitting devices (commonly included). Examples of layers included in the EL layer include light-emitting layers, carrier injection layers (hole injection layers and electron injection layers), carrier transport layers (hole transport layers and electron transport layers), and carrier barrier layers (hole barrier layers and electron barrier layers). In a method for manufacturing a display device according to one embodiment of the present invention, layers constituting a portion of the EL layer can be formed into island shapes for each sub-pixel, and then at least a portion of the sacrificial layer can be removed to form other layers constituting the EL layer (e.g., carrier injection layers, etc.) and a common electrode (also referred to as the upper electrode) in a manner shared by multiple light-emitting devices.

[0050] On the other hand, in many cases, the carrier injection layer is a layer with high conductivity within the EL layer. Therefore, there is a concern that the light-emitting device may short-circuit when the carrier injection layer contacts the side of the island-shaped EL layer or the side of the pixel electrode. In addition, when the carrier injection layer is set in an island shape and a common electrode is formed in a manner shared by multiple light-emitting devices, there is also a concern that the light-emitting device may short-circuit when the common electrode contacts the side of the EL layer or the side of the pixel electrode.

[0051] Thus, a display device according to one embodiment of the present invention includes an insulating layer covering the sides of at least an island-shaped light-emitting layer.

[0052] Thus, it is possible to suppress at least a portion of the island-shaped EL layer and the pixel electrode from contacting the carrier injection layer or the common electrode. Therefore, short circuits in the light-emitting device can be suppressed, thereby improving the reliability of the light-emitting device.

[0053] Furthermore, by providing this insulating layer, the spaces between adjacent island-shaped EL layers can be filled, thus reducing the unevenness of the formed surfaces of the layers (carrier injection layer, common electrode, etc.) provided on the island-shaped EL layers and further achieving planarization. Therefore, the coverage of the carrier injection layer or common electrode can be improved. As a result, disconnection of the common electrode can be prevented.

[0054] In this specification, disconnection refers to the phenomenon that a layer, film, or electrode separates due to the shape of the surface it is formed on (e.g., a step).

[0055] Furthermore, the insulating layer can be provided in contact with the island-shaped EL layers. This prevents the EL layer from peeling off. When the insulating layer is in close contact with the island-shaped EL layers, adjacent island-shaped EL layers can be fixed or bonded together by the insulating layer. Additionally, by suppressing moisture from entering the interface between the pixel electrode and the EL layer, the insulating layer prevents the EL layer from peeling off. This improves the reliability of the light-emitting device. Furthermore, it improves the manufacturing yield of the light-emitting device.

[0056] Furthermore, the insulating layer preferably functions as a barrier insulating layer against at least one of water and oxygen. Additionally, the insulating layer preferably functions as a barrier insulating layer against the diffusion of at least one of water and oxygen. Furthermore, the insulating layer preferably functions as a trapping or fixing (also known as gettering) of at least one of water and oxygen.

[0057] 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 the function of inhibiting the diffusion of the corresponding substance (or, in other words, low permeability). Alternatively, it refers to the function of capturing or fixing the corresponding substance (also known as gettering).

[0058] By using an insulating layer that serves as a barrier or has gettering properties, a structure can be provided that suppresses the entry of impurities (typically at least one of water and oxygen) that may diffuse from the outside into each light-emitting device. By employing this structure, a highly reliable light-emitting device and a highly reliable display device can be provided.

[0059] A display device according to one embodiment of the present invention includes a pixel electrode, a first light-emitting unit on the pixel electrode, a charge-generating layer (also referred to as an intermediate layer) on the first light-emitting unit, a second light-emitting unit on the charge-generating layer, an insulating layer disposed such that it covers each side of the first light-emitting unit, the charge-generating layer, and the second light-emitting unit, and a common electrode on the second light-emitting unit. Alternatively, a common layer shared by light-emitting devices of different colors may be disposed between the second light-emitting unit and the common electrode.

[0060] In many cases, the hole injection layer, electron injection layer, or charge generation layer are layers with high conductivity in the EL layer. In a display device according to one embodiment of the present invention, the sides of the above-mentioned layers are covered by an insulating layer, so contact with common electrodes can be suppressed. Therefore, short circuits in the light-emitting device can be suppressed, thereby improving the reliability of the light-emitting device.

[0061] The insulating layer on the side of the island-shaped EL layer can have either a single-layer structure or a multilayer structure.

[0062] For example, by forming an insulating layer with a single-layer structure using inorganic materials, the insulating layer can be used as a protective insulating layer for the EL layer. This can improve the reliability of the display device.

[0063] Furthermore, when using a multilayer insulating layer, the first insulating layer is in contact with the EL layer, so it is preferable to form it using an inorganic insulating material. In particular, it is preferable to form it using atomic layer deposition (ALD), which causes less film damage. Alternatively, it is preferable to form the inorganic insulating layer using sputtering, chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD), which have higher deposition rates than ALD. This allows for the manufacture of highly reliable display devices with high productivity. Additionally, the second insulating layer is preferably formed using an organic material to planarize the recesses formed in the first insulating layer.

[0064] For example, the first layer of the insulating layer can be an alumina film formed by the ALD method, and the second layer of the insulating layer can be an organic resin film.

[0065] When the side of the EL layer is in direct contact with the organic resin film, organic solvents, etc., contained in the organic resin film may damage the EL layer. By using an inorganic insulating film, such as an alumina film formed by the ALD method, as the first layer of the insulating layer, a structure in which the organic resin film and the side of the EL layer are not in direct contact can be adopted. As a result, the dissolution of the EL layer due to organic solvents can be suppressed.

[0066] Furthermore, in a display device according to one embodiment of the present invention, it is not necessary to provide an insulating layer covering the end of the pixel electrode between the pixel electrode and the EL layer, so the spacing between adjacent light-emitting devices can be very narrow. Therefore, high definition or high resolution of the display device can be achieved. In addition, a mask used to form the insulating layer is not required, so the manufacturing cost of the display device can be reduced.

[0067] Furthermore, by employing a structure in which an insulating layer covering the end of the pixel electrode is not provided between the pixel electrode and the EL layer, i.e., a structure in which no insulating layer is provided between the pixel electrode and the EL layer, light emission from the EL layer can be extracted efficiently. Therefore, the display device according to one embodiment of the present invention can have minimal viewing angle dependence. By reducing viewing angle dependence, the visibility of images in the display device can be improved. For example, in the display device according to one embodiment of the present invention, the viewing angle (the maximum angle that maintains a certain contrast when viewing the screen from an oblique angle) can be 100° or more and less than 180°, preferably 150° or more and less than 170°. In addition, the above-mentioned viewing angle can be used in all directions.

[0068] Furthermore, the structure for suppressing crosstalk is not limited to a structure in which an island-shaped EL layer is formed for each light-emitting device. For example, crosstalk can be suppressed by employing a structure in which a thin region of the EL layer is formed between adjacent light-emitting devices. The presence of a thin region of the EL layer between adjacent light-emitting devices can suppress current flow through the outer side of the region in the EL layer that is in contact with the pixel electrode. Additionally, the region in the EL layer that is in contact with the pixel electrode can be primarily used as the light-emitting region.

[0069] For example, the ratio of the pixel electrode thickness T1 to the EL layer thickness T2, T1 / T2, is preferably 0.5 or more, more preferably 0.8 or more, further preferably 1.0 or more, and even more preferably 1.5 or more. Additionally, when the insulating layer forming the pixel electrode surface in the region between adjacent light-emitting devices has a recess (refer to the insulating layer 255b described in Embodiment 3 below (Fig. 17A, etc.)), the pixel electrode thickness T1 may sometimes be thin. Specifically, regarding the sum of the pixel electrode thickness and the recess depth T3 and the EL layer thickness T2, T3 / T2 is preferably 0.5 or more, more preferably 0.8 or more, further preferably 1.0 or more, and even more preferably 1.5 or more. When the relationship between T1 and T2 or T2 and T3 satisfies the above conditions, it is easy to form a region with a thin EL layer between adjacent light-emitting devices. Furthermore, when an extremely thin region is formed in the EL layer, a portion of the EL layer may separate.

[0070] In addition, the thickness T1 of the pixel electrode or the sum of the above T3 is preferably, for example, 160nm or more, 200nm or more, or 250nm or more and 1000nm or less, 750nm or less, 500nm or less, 400nm or less, or 300nm or less, respectively.

[0071] Furthermore, the angle (also referred to as the taper angle) between the side of the pixel electrode and the surface to be formed is preferably 60° or more and 140° or less, more preferably 70° or more and 140° or less, and even more preferably 80° or more and 140° or less. When the taper angle of the pixel electrode meets the above conditions, it is easy to form a region with a thin EL layer between adjacent light-emitting devices.

[0072] [Example of display device structure] Figures 1 and 2 show a display device according to one embodiment of the present invention.

[0073] FIG1A shows a top view of the display device 100. The display device 100 includes a display section with a plurality of pixels 103 disposed thereon and a connecting section 140 on the outer side of the display section. In the display section, the plurality of sub-pixels are arranged in a matrix. FIG1A shows two rows and six columns of sub-pixels, which constitute two rows and two columns of pixels. The connecting section 140 may also be referred to as a cathode contact section.

[0074] The pixel 103 shown in Figure 1A is composed of three sub-pixels: sub-pixel 110R, sub-pixel 110G, and sub-pixel 110B.

[0075] Subpixel 110R emits red light, subpixel 110G emits green light, and subpixel 110B emits blue light. In this embodiment, a subpixel of three colors—red (R), green (G), and blue (B)—is used as an example, but a subpixel of three colors—yellow (Y), cyan (C), and magenta (M)—can also be used. Furthermore, the type of subpixel is not limited to three; four or more can be used. Examples of four subpixels include: a subpixel of four colors—R, G, B, and white (W); a subpixel of four colors—R, G, B, and Y; and a subpixel of four colors—R, G, B, and infrared (IR) light; etc.

[0076] Alternatively, it can be said that the pixel 103 shown in Figure 1A is arranged in stripes.

[0077] In this specification, the row direction is sometimes referred to as the X direction and the column direction as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly (see Figure 1A).

[0078] In the example shown in Figure 1A, subpixels of different colors are arranged in the X direction, and subpixels of the same color are arranged in the Y direction. Note that it is also possible for subpixels of different colors to be arranged in the Y direction and subpixels of the same color to be arranged in the X direction.

[0079] In the example shown in FIG1A, the connecting portion 140 is located below the display portion when viewed from above, but there are no particular restrictions on it. The connecting portion 140 can be provided at least one of the positions on the upper, right, left, and lower sides of the display portion when viewed from above, or it can be provided in a manner that surrounds the four sides of the display portion. As for the top surface shape of the connecting portion 140, it can be, for example, a strip shape, an L-shape, a U-shape, or a frame shape. Furthermore, the number of connecting portions 140 can be one or more.

[0080] Figure 1B is a cross-sectional view of the dashed line A1-A2 in Figure 1A. Figure 2A is a cross-sectional view of the dashed line B1-B2 in Figure 1A. Figures 2B and 2C are cross-sectional views of the dashed line C1-C2 in Figure 1A.

[0081] As shown in Figures 1B and 2A, in the display device 100, light-emitting devices 130 are disposed on a layer 101 including transistors, and a protective layer 131 is disposed to cover these light-emitting devices. Color layers 132R, 132G, and 132B are disposed on the protective layer 131, and a substrate 120 is 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 disposed in the area between adjacent light-emitting devices.

[0082] Figures 1B and 2A show multiple insulating layers 125 and multiple insulating layers 127, but when viewed from above, the insulating layers 125 and 127 can be formed as a continuous layer. In other words, the display device 100 may include, for example, one insulating layer 125 and one insulating layer 127. Alternatively, the display device 100 may also include multiple insulating layers 125 and multiple insulating layers 127 that are separate from each other.

[0083] The display device of one embodiment of the present invention may also employ any of the following structures: a top emission structure that emits light in the direction opposite to that of the substrate on which the light-emitting device 130 is formed, a bottom emission structure that emits light in one side of the substrate on which the light-emitting device 130 is formed, and a dual emission structure that emits light in both directions.

[0084] The layer 101 containing transistors can, for example, adopt a stacked structure, wherein a plurality of transistors are disposed on a substrate, and an insulating layer is disposed to cover these transistors. The layer 101 including transistors may also have recesses between adjacent light-emitting devices 130. For example, the insulating layer located on the outermost surface of the layer 101 including transistors may also have recesses. Structural examples of the layer 101 including transistors will be described later in Embodiments 2 and 3.

[0085] Each sub-pixel includes a light-emitting device 130, which includes an EL layer 113 and a common layer 114. In addition, the common layer 114 can also be considered as part of the EL layer in the light-emitting device. In this specification, the island-shaped layer in the EL layer included by each light-emitting device is referred to as the EL layer 113, and the layer shared by multiple light-emitting devices is referred to as the common layer 114.

[0086] Multiple EL layers 113 are all configured as islands. Multiple EL layers 113 can have the same structure.

[0087] For example, the EL layer 113 may include a light-emitting material that emits blue light and a light-emitting material that emits light with a longer wavelength than blue. For example, the EL layer 113 may have a structure that includes a light-emitting material that emits blue light and a light-emitting material that emits yellow light; or a structure that includes a light-emitting material that emits blue light, a light-emitting material that emits green light, and a light-emitting material that emits red light; etc.

[0088] The EL layer 113 includes a plurality of light-emitting units. In this embodiment, an example is shown in which the EL layer 113 includes two light-emitting units. Specifically, the EL layer 113 includes a first light-emitting unit 113a, a charge-generating layer 113b, and a second light-emitting unit 113c.

[0089] Each light-emitting unit includes a light-emitting layer. For example, when the light emitted by multiple light-emitting units is in a complementary color relationship, the light-emitting device 130 can emit white light.

[0090] In addition, by employing the microcavity structure described later, the light-emitting device 130 that emits white light sometimes enhances specific colors such as red, green or blue to emit light.

[0091] As the light-emitting device 130, it is preferable to use an EL device such as an OLED (Organic Light Emitting Diode) or a QLED (Quantum-dot Light Emitting Diode). Examples of light-emitting materials (also called luminescent materials) included in the EL device include fluorescent materials, phosphorescent materials, inorganic compounds (quantum dot materials, etc.), and materials exhibiting thermally activated delayed fluorescence (TADF materials). Furthermore, as the TADF material, materials in thermal equilibrium between singlet and triplet excited states can also be used. Because such TADF materials have a short emission lifetime (excitation lifetime), efficiency reduction in the high-brightness region of the light-emitting device can be suppressed. In addition, inorganic compounds (e.g., quantum dot materials) can also be used as the light-emitting material included in the EL device.

[0092] The light-emitting device 130 includes an EL layer between a pair of electrodes. The EL layer includes at least a light-emitting layer. In this specification, etc., one of the pair of electrodes is sometimes referred to as the pixel electrode and the other as the common electrode.

[0093] In a pair of electrodes included in a light-emitting device, one electrode is used as an anode and the other electrode is used as a cathode. The following explanation sometimes uses the case where the pixel electrode is used as the anode and the common electrode is used as the cathode as an example.

[0094] The light-emitting device 130 includes a pixel electrode 111 on a layer 101 having a transistor, an island-shaped EL layer 113 on the pixel electrode 111, a common layer 114 on the EL layer 113, and a common electrode 115 on the common layer 114.

[0095] The EL layer 113 includes at least a light-emitting layer. Alternatively, the EL layer 113 may also include one or more of the following: a hole injection layer, a hole transport layer, a hole barrier layer, a charge generation layer, an electron barrier layer, an electron transport layer, and an electron injection layer.

[0096] The first light-emitting unit 113a and the second light-emitting unit 113c each include at least one light-emitting layer. Alternatively, the first light-emitting unit 113a and the second light-emitting unit 113c may each include one or more of the following: a hole injection layer, a hole transport layer, a hole barrier layer, an electron barrier layer, an electron transport layer, and an electron injection layer.

[0097] The common layer 114 may include, for example, an electron injection layer or a hole injection layer. Alternatively, the common layer 114 may be a stack of an electron transport layer and an electron injection layer, or a stack of a hole transport layer and a hole injection layer. Multiple light-emitting devices 130 may share the common layer 114, for example, all light-emitting devices 130 may share the common layer 114.

[0098] The light-emitting device in this embodiment adopts a series structure. In this embodiment, an example is shown where the light-emitting device includes two light-emitting units, but the number of light-emitting units included in the light-emitting device may also be three or more.

[0099] Furthermore, multiple light-emitting devices 130 share a common electrode 115, for example, all light-emitting devices 130 share a common electrode 115. The common electrode 115 shared by the multiple light-emitting devices 130 is electrically connected to a conductive layer 123 disposed in the connection portion 140 (see Figures 2B and 2C). The conductive layer 123 can be a conductive layer formed using the same material as the pixel electrode 111 and by the same process as the pixel electrode 111.

[0100] Additionally, FIG. 2B shows an example where a common layer 114 is provided on the conductive layer 123 and the conductive layer 123 and the common electrode 115 are electrically connected through the common layer 114. The connection portion 140 may also not have a common layer 114. For example, FIG. 2C shows an example where there is no common layer 114 on the conductive layer 123 and the conductive layer 123 and the common electrode 115 are directly connected. For example, by using a mask (also called a range mask or coarse metal mask, etc.) to define the deposition range, the area deposited by the common layer 114 and the common electrode 115 can be changed.

[0101] There is no particular limitation on the shape and size relationship between the pixel electrode 111 and the EL layer 113. In the examples shown in FIG1B and FIG2A, the end of the EL layer 113 is located inside the end of the pixel electrode 111. FIG3A is an enlarged view of the light-emitting device shown in FIG1B and FIG2A. In FIG3A, the end of the EL layer 113 is located on the pixel electrode 111. In the example shown in FIG3A, the EL layer 113 is located in the center of the pixel electrode 111, and the width X1 of the left region of the pixel electrode 111 that does not overlap with the EL layer 113 and the width X2 of the right region are equal or approximately equal. Alternatively, the EL layer 113 may be offset to any end of the pixel electrode 111. In the example shown in FIG3B, the EL layer 113 is offset to the right end of the pixel electrode 111 and the width X2 is narrower than the width X1.

[0102] Additionally, the end of the EL layer 113 may include both a portion located outside the end of the pixel electrode 111 and a portion located inside the end of the pixel electrode 111. In FIG. 3C, the end of the EL layer 113 is located outside the end of the pixel electrode 111 and covers the end of the pixel electrode 111. Specifically, in the example shown in FIG. 3C, the left end of the EL layer 113 is located inside the left end of the pixel electrode 111, and the right end of the EL layer 113 covers the right end of the pixel electrode 111.

[0103] Additionally, Figure 4 shows an example where the end of the EL layer 113 is located outside the end of the pixel electrode 111. In Figure 4, the EL layer 113 is arranged to cover the end of the pixel electrode 111.

[0104] In addition, the end of the pixel electrode 111 may be aligned or approximately aligned with the end of the EL layer 113.

[0105] In cases where the ends are aligned or substantially aligned and the top surface shapes are consistent or substantially consistent, it can be said that, when viewed from above, at least a portion of the outline overlaps with each other between the stacked layers. For example, this includes cases where the upper and lower layers are processed by the same masking pattern or a portion thereof. However, there are actually cases where the edges do not overlap, and sometimes the upper layer is inside the lower layer or outside the lower layer; in such cases, it can also be said that the ends are "substantially aligned" or the "top surface shapes are substantially consistent".

[0106] Additionally, the end of the pixel electrode 111 may also have a tapered shape. By making the side of the pixel electrode 111 tapered, the coverage of the insulating layer 125 provided along the side of the pixel electrode 111 can be improved. Furthermore, by making the side of the pixel electrode 111 tapered, foreign matter (e.g., debris or particles) during the manufacturing process can be easily removed by washing or other methods, which is preferable.

[0107] Preferably, a protective layer 131 is provided on the light-emitting device 130. By providing the protective layer 131, the reliability of the light-emitting device can be improved. The protective layer 131 can have a single-layer structure or a stacked structure of two or more layers.

[0108] There are no limitations on the conductivity of the protective layer 131. At least one of an insulating film, a semiconductor film, and a conductive film can be used as the protective layer 131.

[0109] When the protective layer 131 includes an inorganic film, it can suppress the deterioration of the light-emitting device, such as preventing the oxidation of the common electrode 115 and suppressing impurities (moisture, oxygen, etc.) from entering the light-emitting device 130, thereby improving the reliability of the display device.

[0110] As the protective layer 131, inorganic insulating films such as oxide insulating films, nitride insulating films, oxynitride insulating films, and oxynitride insulating films can be used. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxynitride insulating films include silicon oxynitride films and aluminum oxynitride films. Examples of oxynitride insulating films include silicon oxynitride films and aluminum oxynitride films.

[0111] The protective layer 131 preferably includes a nitrided insulating film or a nitrogen-oxidized insulating film, and more preferably includes a nitrided insulating film.

[0112] Alternatively, an inorganic film comprising In-Sn oxide (also known as ITO), In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or indium gallium zinc oxide (also known as In-Ga-Zn oxide, IGZO) may be used for the protective layer 131. This inorganic film preferably has high resistance; specifically, it preferably has a resistance higher than that of the common electrode 115. The inorganic film may also contain nitrogen.

[0113] When the light emitted by the light-emitting device is extracted through the protective layer 131, the visible light transmittance of the protective layer 131 is preferably high. For example, ITO, IGZO and alumina are inorganic materials with high visible light transmittance, so they are preferred.

[0114] As the protective layer 131, for example, a laminated structure of an alumina film and a silicon nitride film on the alumina film, or a laminated structure of an alumina film and an IGZO film on the alumina film, can be used. By using this laminated structure, impurities (such as water and oxygen) can be suppressed from entering the EL layer side.

[0115] Furthermore, the protective layer 131 may also include an organic membrane. For example, the protective layer 131 may also include both an organic membrane and an inorganic membrane.

[0116] The protective layer 131 may also have a two-layer structure formed using different film-forming 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.

[0117] In sub-pixel 110R, a color layer 132R that transmits red light is provided on the protective layer 131. Thus, in sub-pixel 110R, the light emitted by the light-emitting device 130 is extracted as red light through the color layer 132R and sent to the outside of the display device 100. Furthermore, multiple adjacent sub-pixels 110R can share the color layer 132R. Alternatively, the color layer 132R can be provided one per sub-pixel 110R.

[0118] Similarly, in the sub-pixel 110G, a color layer 132G that transmits green light is provided on the protective layer 131. Thus, in the sub-pixel 110G, the light emitted by the light-emitting device 130 is extracted as green light through the color layer 132G and sent to the outside of the display device 100.

[0119] In addition, in sub-pixel 110B, a color layer 132B that transmits green light is provided on the protective layer 131. Thus, in sub-pixel 110B, the light emitted by the light-emitting device 130 is extracted as blue light through the color layer 132B and sent to the outside of the display device 100.

[0120] In the examples shown in Figures 1B and 2A, color layers 132R, 132G, and 132B are directly disposed on the light-emitting device 130 through a protective layer 131. By adopting this structure, the accuracy of the alignment between the light-emitting device 130 and the color layers can be improved. In addition, by bringing the positions of the light-emitting device 130 and the color layers closer together, color mixing can be suppressed and viewing angle characteristics can be improved, which is preferable.

[0121] Alternatively, as shown in FIG5A, a resin layer 122 can be used to bond the substrate 120, on which the color layers 132R, 132G, and 132B are provided, to the protective layer 131. By providing the color layers 132R, 132G, and 132B on the substrate 120, the temperature of the heat treatment in the formation process of the aforementioned color layers can be increased.

[0122] Although not shown, an insulating layer may be provided covering the end of the top surface of the pixel electrode 111. The EL layer 113 may have a portion that contacts the pixel electrode 111 and a portion that contacts the insulating layer. The insulating layer may be a single-layer structure or a stacked structure utilizing one or both of inorganic and organic insulating films.

[0123] Examples of organic insulating materials that can be used as insulating layers covering the ends of pixel electrodes 111 include acrylic resins, epoxy resins, polyimide resins, polyamide resins, polyimide-amide resins, polysiloxane resins, benzocyclobutene resins, and phenolic resins. Alternatively, inorganic insulating films suitable for use in the insulating layer can be used, specifically inorganic insulating films suitable for the protective layer 131.

[0124] When an inorganic insulating film is used as the insulating layer covering the end of the pixel electrode 111, impurities are less likely to enter the light-emitting device 130 compared to the case where an organic insulating film is used, thereby improving the reliability of the light-emitting device 130. When an organic insulating film is used as the insulating layer covering the end of the pixel electrode 111, the step coverage is better and less affected by the shape of the pixel electrode compared to the case where an inorganic insulating film is used. Therefore, short circuits in the light-emitting device 130 can be prevented. Specifically, when an organic insulating film is used as the insulating layer, the insulating layer can be processed into a conical shape or the like. Note that in this specification, a conical shape refers to a shape in which at least a portion of the side surface of the component is inclined relative to the substrate surface or the surface to which it is formed. For example, it is preferable to have a region where the angle (also called the cone angle) formed by the inclined side surface and the substrate surface or the surface to which it is formed is less than 90°.

[0125] The side surfaces of the pixel electrode 111 and the EL layer 113 are covered by insulating layers 125 and 127. This prevents the common layer 114 (or common electrode 115) from contacting the side surfaces of the pixel electrode 111 and the EL layer 113, and suppresses short circuits in the light-emitting device. This improves the reliability of the light-emitting device.

[0126] The insulating layer 125 preferably covers at least one of the side surface of the pixel electrode 111 and the side surface of the EL layer 113, and more preferably covers both the side surface of the pixel electrode 111 and the side surface of the EL layer 113. The insulating layer 125 may have a structure that contacts each side surface of the pixel electrode 111 and the EL layer 113.

[0127] The insulating layer 127 is disposed on the insulating layer 125 in such a way that it fills the recess of the insulating layer 125. The insulating layer 127 may be in a structure that overlaps with each side of the pixel electrode 111 and the EL layer 113 through the insulating layer 125 (or in other words, a structure that covers the sides).

[0128] By providing insulating layers 125 and 127, the interlayer spaces between adjacent islands can be filled, thus reducing the unevenness of the formed surface of the layer (e.g., common electrode) provided on the island-shaped layer and further achieving planarization. Therefore, the coverage of the common electrode can be improved and the disconnection of the common electrode can be prevented.

[0129] A common layer 114 and a common electrode 115 are disposed on an EL layer 113, an insulating layer 125, and an insulating layer 127. Before the insulating layer 125 and the insulating layer 127 are disposed, a step is generated between the region where the pixel electrode 111 and the EL layer 113 are disposed and the region where the pixel electrode 111 and the EL layer 113 are not disposed (the region between light-emitting devices). In a display device according to one embodiment of the present invention, by including the insulating layer 125 and the insulating layer 127, this step can be planarized, thereby improving the coverage of the common layer 114 and the common electrode 115. Therefore, poor connection due to the disconnection of the common electrode 115 can be suppressed. Furthermore, the resistance increase caused by the localized thinning of the common electrode 115 due to the step can be suppressed.

[0130] In order to improve the flatness of the surfaces on which the common layer 114 and the common electrode 115 are formed, the heights of the top surfaces of the insulating layer 125 and the insulating layer 127 are preferably the same as or approximately the same as the height of the top surface of the end of the EL layer 113 (or, in other words, the height of the end of the top surface of the EL layer 113). In addition, although the top surface of the insulating layer 127 is preferably flat, it may also have a convex portion, a convex curved surface, a concave curved surface, or a concave portion.

[0131] Furthermore, the insulating layer 125 or the insulating layer 127 can be disposed in contact with the island-shaped EL layer 113. By making the insulating layer 125 or the insulating layer 127 in close contact with the EL layer 113, the adjacent EL layers 113 can be fixed or bonded together by the insulating layer 125 or the insulating layer 127. This prevents the film peeling of the EL layer 113, thus improving the reliability of the light-emitting device. Additionally, it can improve the manufacturing yield of the light-emitting device.

[0132] Alternatively, either insulating layer 125 or insulating layer 127 may be omitted. For example, by forming an insulating layer 125 with a single-layer structure using an inorganic material, insulating layer 125 can be used as a protective insulating layer for EL layer 113. This can improve the reliability of the display device. Alternatively, by forming an insulating layer 127 with a single-layer structure using an organic material, planarization can be achieved by filling the spaces between adjacent EL layers 113 with insulating layer 127. This can improve the coverage of the common electrode 115 (upper electrode) formed on EL layer 113 and insulating layer 127.

[0133] FIG5B shows an example without the insulating layer 125. When the insulating layer 125 is not provided, the insulating layer 127 can contact each side of the pixel electrode 111 and the EL layer 113. The insulating layer 127 can be provided in such a way that it fills the spaces between the EL layers 113 included in each light-emitting device 130.

[0134] At this time, it is preferable to use an organic material that causes less damage to the EL layer 113 as the insulating layer 127. For example, it is preferable to use an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, or polyamide resin that is soluble in alcohol.

[0135] Additionally, Figure 5C shows an example where the insulating layer 127 is not provided.

[0136] Note that Figure 5C shows an example of a recess in which the common layer 114 is embedded in the insulating layer 125, but a void may also be formed in this area.

[0137] The insulating layer 125 has an area that contacts the side of the EL layer 113 and serves as a protective insulating layer for the EL layer 113. By providing the insulating layer 125, impurities (such as oxygen and moisture) can be prevented from entering the interior from the side of the EL layer 113, thereby enabling a display device with high reliability.

[0138] The insulating layer 125 can be an insulating layer comprising inorganic materials. For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxynitride insulating films, and oxynitride insulating films can be used as the insulating layer 125. The insulating layer 125 can have a single-layer structure or a multilayer structure. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, magnesium oxide films, indium gallium zinc oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxynitride insulating films include silicon oxynitride films and aluminum oxynitride films. Examples of oxynitride insulating films include silicon oxynitride films and aluminum oxynitride films. Especially, a high selectivity ratio of aluminum oxide to the EL layer during etching is preferred, as it protects 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 alumina film, hafnium oxide film, or silicon oxide film formed using the ALD method to the insulating layer 125, an insulating layer 125 with few pinholes and good protection of the EL layer can be formed. Alternatively, the insulating layer 125 can also be a laminated structure of a film formed using the ALD method and a film formed using the sputtering method. For example, the insulating layer 125 can be a laminated structure of an alumina film formed using the ALD method and a silicon nitride film formed using the sputtering method.

[0139] In this specification, etc., oxynitrides refer to materials in which the oxygen content is greater than the nitrogen content in their composition, while nitrogen oxides refer to materials in which the nitrogen content is greater than the oxygen content in their composition. For example, when referred to as "silicon oxynitride", it refers to materials in which the oxygen content is greater than the nitrogen content in their composition, while when referred to as "silicon oxynitride", it refers to materials in which the nitrogen content is greater than the oxygen content in their composition.

[0140] Furthermore, the insulating layer 125 preferably functions as a barrier insulating layer against at least one of water and oxygen. Additionally, the insulating layer 125 preferably functions as a barrier insulating layer against at least one of water and oxygen. Furthermore, the insulating layer 125 preferably functions as a trapping or fixing (also referred to as gettering) of at least one of water and oxygen.

[0141] When the insulating layer 125 is used as a barrier insulating layer or an insulating layer with gettering function, it can have a structure that inhibits the entry of impurities (typically at least one of water and oxygen) that may diffuse from the outside into each light-emitting device. By adopting this structure, a highly reliable light-emitting device can be provided, and a highly reliable display device can also be provided.

[0142] Furthermore, the impurity concentration in the insulating layer 125 is preferably low. This prevents impurities from mixing into the EL layer from the insulating layer 125 and causing EL layer degradation. Additionally, by reducing the impurity concentration in the insulating layer 125, the barrier properties against at least one of water and oxygen can be improved. For example, preferably, one of the hydrogen concentration and carbon concentration in the insulating layer 125 is sufficiently low, and preferably both the hydrogen concentration and carbon concentration are sufficiently low.

[0143] Examples of methods for forming the insulating layer 125 include sputtering, CVD, pulsed laser deposition (PLD), and ALD. The insulating layer 125 is preferably formed using the ALD method, which has good coverage.

[0144] By increasing the substrate temperature during the deposition of the insulating layer 125, an insulating layer 125 with a thin film thickness, low impurity concentration, and high barrier properties against at least one of water and oxygen can be formed. Therefore, the substrate temperature is preferably 60°C or higher, more preferably 80°C or higher, further preferably 100°C or higher, and even more preferably 120°C or higher. On the other hand, since the insulating layer 125 is deposited after the formation of the island-shaped EL layer, it is preferably formed at a temperature lower than the heat resistance temperature of the EL layer. Therefore, the substrate temperature is preferably 200°C or lower, more preferably 180°C or lower, further preferably 160°C or lower, even more preferably 150°C or lower, and even more preferably 140°C or lower.

[0145] As indicators of heat resistance temperature, examples include glass transition point, softening point, melting point, thermal decomposition temperature, and 5% weight loss temperature. Any of the above-mentioned temperatures can be used as the heat resistance temperature of the EL layer, but the lowest temperature among them is preferred.

[0146] The insulating layer 127 disposed on the insulating layer 125 has the function of planarizing the recesses of the insulating layer 125 formed between adjacent light-emitting devices. In other words, by including the insulating layer 127, the flatness of the surface on which the common electrode 115 is formed is improved. As the insulating layer 127, an insulating layer containing organic materials can be used. For example, acrylic resin, polyimide resin, epoxy resin, amide resin, polyamide resin, polyamide amide resin, silicone resin, silicone resin, benzocyclobutene resin, phenolic resin, and precursors of the above resins can be used as the insulating layer 127. In addition, as the insulating layer 127, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can also be used. In addition, as the insulating layer 127, a photosensitive resin can also be used. Photoresist can also be used as a photosensitive resin. Photosensitive resins can be either positive or negative materials.

[0147] The insulating layer 127 can also be made of a material that absorbs visible light. By absorbing the light emitted from the light-emitting device through the insulating layer 127, light leakage (stray light) from the light-emitting device to adjacent light-emitting devices can be suppressed. This improves the display quality of the display device. Furthermore, the display quality can be improved even without using a polarizing plate in the display device, thus enabling the display device to be lightweight and thin.

[0148] Examples of materials that absorb visible light include pigments such as black, dyes, light-absorbing resins (e.g., polyimide), and resins that can be used in color filters (color filter materials). In particular, resin materials made by mixing color filter materials of two or more colors can improve the effect of blocking visible light, and are therefore preferred. Especially, by mixing color filter materials of three or more colors, a black or near-black resin layer can be achieved.

[0149] Figures 6A to 6F show the cross-sectional structure including the insulating layer 127 and the surrounding region 139.

[0150] FIG6A shows an example where the thickness of the pixel electrode varies depending on the sub-pixels of each color. FIG6A shows an example where pixel electrode 111a has a two-layer structure and pixel electrode 111b has a single-layer structure. Specifically, the thicknesses of pixel electrode 111a and pixel electrode 111b are different. Since the EL layer 113 is formed across each color sub-pixel, the thickness of the EL layer 113 on pixel electrode 111a is equal to or approximately equal to the thickness of the EL layer 113 on pixel electrode 111b. Therefore, the heights of the top surfaces of the EL layer 113 on pixel electrode 111a and pixel electrode 111b are different. The height of the top surface of the insulating layer 125 is the same as or approximately the same as the height of the top surface of the EL layer 113 on both the pixel electrode 111a side and the pixel electrode 111b side. In addition, the top surface of the insulating layer 127 has a gentle slope that is higher on the pixel electrode 111a side and lower on the pixel electrode 111b side. Thus, the heights of insulating layers 125 and 127 are preferably the same as the height of the top surface of the adjacent EL layer. Alternatively, insulating layers 125 and 127 may also have a flat portion whose height is the same as the top surface of any one of the adjacent EL layers.

[0151] In FIG6B, the top surface of the insulating layer 127 has a region that is higher than the top surface of the EL layer 113. As shown in FIG6B, the top surface of the insulating layer 127 has a central and peripheral bulging shape when viewed in cross-section, that is, a convex curved shape.

[0152] In FIG. 6C, the top surface of the insulating layer 127, when viewed in cross-section, has the following shape: a shape that expands gently towards the center, i.e., has a convex surface, and a shape that is recessed in the center and around the periphery, i.e., has a concave surface. The insulating layer 127 has a region that is higher than the top surface of the EL layer 113. In addition, in region 139, the display device includes at least one of the sacrificial layer 118 and the sacrificial layer 119. The ends of the insulating layer 125 and the insulating layer 127 both overlap with the top surface of the EL layer 113 and are located above at least one of the sacrificial layers 118 and 119.

[0153] In Figure 6D, the top surface of the insulating layer 127 has a region that is lower than the top surface of the EL layer 113. In addition, the top surface of the insulating layer 127 has a shape with a central and peripheral depression when viewed in cross-section, that is, it has a concave curved surface.

[0154] In FIG6E, the top surface of the insulating layer 125 has a region that is higher than the top surface of the EL layer 113. In other words, on the surface where the common layer 114 is formed, the insulating layer 125 protrudes to form a protrusion.

[0155] For example, when the insulating layer 125 is formed in a manner that is consistent or substantially consistent with the height of the sacrificial layer, as shown in FIG6E, the insulating layer 125 is sometimes formed in a protruding shape.

[0156] In FIG6F, the top surface of the insulating layer 125 has a region that is lower than the top surface of the EL layer 113. In other words, a recess is formed in the insulating layer 125 on the surface of the common layer 114.

[0157] Thus, insulating layer 125 and insulating layer 127 can take various shapes.

[0158] As a sacrificial layer, one or more inorganic films such as metal films, alloy films, metal oxide films, semiconductor films, and inorganic insulating films can be used.

[0159] As a sacrificial layer, for example, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium and tantalum, as well as alloy materials containing such metallic materials can be used.

[0160] Alternatively, metal oxides such as In-Ga-Zn oxide can be used as the sacrificial layer. For example, an In-Ga-Zn oxide film can be formed using sputtering. Furthermore, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), and indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide) can be used as the sacrificial film. Alternatively, silicon-containing indium tin oxide can also be used.

[0161] Note that element M (which is one or more of aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) can also be used to replace gallium.

[0162] Furthermore, various inorganic insulating films suitable for use in the protective layer 131 can be used as the sacrificial layer. In particular, the adhesion between the oxide insulating film and the EL layer is higher than that between the nitride insulating film and the EL layer, so it is preferred. For example, inorganic insulating materials such as alumina, hafnium oxide, and silicon oxide can be used as the sacrificial layer. For example, an alumina film can be formed using the ALD method as the sacrificial layer. By using the ALD method, damage to the substrate (especially the EL layer, etc.) can be reduced, so it is preferred. For example, a silicon nitride film can be formed using sputtering as the sacrificial layer.

[0163] For example, the sacrificial layer may be a stacked structure of an inorganic insulating film (e.g., an alumina film) formed by ALD and an In-Ga-Zn oxide film formed by sputtering. Alternatively, the sacrificial layer may be a stacked structure of an inorganic insulating film (e.g., an alumina film) formed by ALD and an aluminum film, tungsten film, or inorganic insulating film (e.g., a silicon nitride film) formed by sputtering.

[0164] The display device of this embodiment can reduce the distance between light-emitting devices. Specifically, the distance between light-emitting devices, the distance between EL layers, or the distance between pixel electrodes can be reduced to less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 10 nm or less. In other words, the display device of this embodiment has a region where the spacing between two adjacent EL layers 113 is less than 1 μm, preferably a region where the spacing is less than 0.5 μm (500 nm), and more preferably a region where the spacing is less than 100 nm.

[0165] A light-shielding layer may also be provided on the surface of the substrate 120 on the side of the resin layer 122. Furthermore, various optical components may be disposed on the outer side of the substrate 120. As optical components, polarizing plates, retardation plates, light diffusion layers (diffusion films, etc.), anti-reflective layers, and condensing films may be used. In addition, surface protective layers such as antistatic films that inhibit dust adhesion, water-repellent films that are not easily soiled, hard coatings that inhibit damage during use, and buffer layers may also be disposed on the outer side of the substrate 120. For example, by providing a glass layer or a silicon dioxide layer (SiOx layer) as a surface protective layer, it is preferable to prevent the surface from being soiled or damaged. Additionally, DLC (diamond-like carbon), alumina (AlOx), polyester materials, or polycarbonate materials may also be used as surface protective layers. Furthermore, it is preferable to use a material with high visible light transmittance as a surface protective layer. Furthermore, it is preferable to use a material with high hardness as a surface protective layer.

[0166] The substrate 120 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, or semiconductor, etc. The substrate on the side from which light from the light-emitting device is taken out uses a material that allows light to pass through. Using a flexible material as the substrate 120 can improve the flexibility of the display device, thus realizing a flexible display. Alternatively, a polarizing plate can also be used as the substrate 120.

[0167] As the substrate 120, the following materials can be used: polyester resins such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyether ether (PES) resin, polyamide resin (nylon, aromatic polyamide, 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, and cellulose nanofibers, etc. As the substrate 120, glass whose thickness allows for flexibility can also be used.

[0168] When a circular polarizer is superimposed on a display device, it is preferable to use a substrate with high optical isotropy as the substrate included in the display device. The substrate with high optical isotropy has lower birefringence (or, in other words, less birefringence).

[0169] The absolute value of the retardation value of the substrate with high optical isotropy is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0170] Among thin films with high optical isotropy, examples include cellulose triacetate (also known as TAC) films, cyclic olefin polymer (COP) films, cyclic olefin copolymer (COC) films, and acrylic films.

[0171] When a thin film is used as a substrate, the display panel may experience shape changes such as wrinkles due to water absorption by the film. Therefore, it is preferable to use a thin film with a low water absorption rate as the substrate. For example, it is preferable to use a thin film with a water absorption rate of 1% or less, more preferably a thin film with a water absorption rate of 0.1% or less, and even more preferably a thin film with a water absorption rate of 0.01% or less.

[0172] As the resin layer 122, various 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, 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 can also be used. Furthermore, adhesive sheets can also be used.

[0173] Next, materials that can be used in light-emitting devices will be described.

[0174] The electrode serving as the light-extracting side of the pixel electrode and the common electrode uses a conductive film that transmits visible light. Conversely, the electrode serving as the non-light-extracting side preferably uses a conductive film that reflects visible light. Furthermore, when the display device includes a light-emitting device that emits infrared light, it is preferable to use a conductive film that transmits both visible and infrared light as the light-extracting side electrode and a conductive film that reflects both visible and infrared light as the non-light-extracting side electrode.

[0175] Alternatively, the electrode on the side that does not extract light can also be a conductive film that transmits visible light. In this case, it is preferable to place the electrode between the reflective layer and the EL layer. In other words, the light emitted from the EL layer can also be reflected by the reflective layer and extracted from the display device. Various materials that reflect light can be used as the reflective layer. One or more of insulators, semiconductors, and conductors can be used as the reflective layer. The reflectivity of the reflective layer for visible light is preferably 40% or more and 100% or less, more preferably 70% or more and 100% or less.

[0176] As materials for forming a pair of electrodes (pixel electrode and common electrode) of a light-emitting device, metals, alloys, conductive compounds, and mixtures thereof can be appropriately used. Specifically, examples include aluminum alloys such as indium tin oxide (also known as In-Sn oxide, ITO), In-Si-Sn oxide (also known as ITSO), indium zinc oxide (In-Zn oxide), In-W-Zn oxide, alloys of aluminum, nickel, and lanthanum (Al-Ni-La), and alloys containing silver such as alloys of silver and magnesium, and alloys of silver, palladium, and copper (also referred to as Ag-Pd-Cu, APC). In addition to the above, other examples include aluminum (Al), magnesium (Mg), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and other metals, as well as alloys of these metals. Furthermore, elements belonging to Group 1 or Group 2 of the periodic table (e.g., rare earth metals such as lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), europium (Eu), ytterbium (Yb), alloys of these metals, and graphene, can be used.

[0177] The light-emitting device preferably employs an optical microcavity resonator (microcavity) structure. Therefore, one of the pair of electrodes included in the light-emitting device is preferably an electrode that is both transmissive and reflective to visible light (a semi-transmissive and semi-reflective electrode), and the other is preferably an electrode that is reflective to visible light (a reflective electrode). When the light-emitting device has a microcavity structure, the light emitted from the light-emitting layer can resonate between the two electrodes, and the light emitted from the light-emitting device can be enhanced.

[0178] Note that a semi-transparent and semi-reflective electrode can be a stacked structure of a reflective electrode and an electrode that is transparent to visible light (also known as a transparent electrode).

[0179] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode with a visible light transmittance (light with a wavelength of 400 nm or more and less than 750 nm) of 40% or more in the light-emitting device. The reflectance of the semi-transparent and semi-reflective electrode to visible light is 10% or more and less than 95%, preferably 30% or more and less than 80%. The reflective electrode to visible light has a reflectance of 40% or more and less than 100%, preferably 70% or more and less than 100%. In addition, the resistivity of these electrodes is preferably 1 × 10⁻² Ωcm or less.

[0180] The luminescent layer is a layer that includes a luminescent material (also known as a luminescent substance). The luminescent layer may contain one or more luminescent substances. As a luminescent substance, substances that emit light in colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red are appropriately used. In addition, substances that emit near-infrared light may also be used as luminescent substances.

[0181] As luminescent materials, examples include fluorescent materials, phosphorescent materials, TADF materials, quantum dot materials, etc.

[0182] As fluorescent materials, examples include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fumonisin derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoline derivatives, quinoline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, naphthalene derivatives, etc.

[0183] As phosphorescent materials, examples include organometallic complexes (especially iridium complexes) having a 4H-triazole skeleton, a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, a pyrazine skeleton, or a pyridine skeleton, organometallic complexes (especially iridium complexes) with phenylpyridine derivatives having electron-withdrawing groups as ligands, platinum complexes, rare earth metal complexes, etc.

[0184] In addition to the luminescent material (guest material), the luminescent layer may also contain one or more organic compounds (host material, auxiliary material, etc.). As one or more organic compounds, one or both of hole transport materials and electron transport materials may be used. Furthermore, as one or more organic compounds, bipolar materials or TADF materials may also be used.

[0185] For example, the light-emitting layer is preferably a combination comprising a phosphorescent material, a hole transport material that readily forms excited-state complexes, and an electron transport material. By employing such a structure, ExTET (Exciplex-Triplet Energy Transfer) luminescence, utilizing energy transfer from the excited-state complex to the luminescent material (phosphorescent material), can be efficiently obtained. By selecting a combination of excited-state complexes that form light whose wavelength overlaps with the absorption band on the lowest energy side of the luminescent material, energy transfer can be facilitated, resulting in efficient luminescence, which is therefore preferable. This structure enables the simultaneous realization of high efficiency, low-voltage operation, and long lifetime of the light-emitting device.

[0186] The EL layer 113 (or light-emitting unit) may include, in addition to the light-emitting layer, a layer containing a material with high hole injection capacity, a material with high hole transport capacity (also referred to as a hole transport material), a hole blocking material, a material with high electron transport capacity (also referred to as an electron transport material), a material with high electron injection capacity, an electron blocking material, or a bipolar material (also referred to as a material with high electron transport and hole transport capacity, or a bipolar material).

[0187] Light-emitting devices may use low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-emitting device may be formed by methods such as vapor deposition (including vacuum vapor deposition), transfer printing, printing, inkjet printing, coating, etc.

[0188] For example, the EL layer 113 (or light-emitting unit) may also include one or more of the following: hole injection layer, hole transport layer, hole barrier layer, electron barrier layer, electron transport layer and electron injection layer.

[0189] The common layer 114 may also be one or more of the following: a hole injection layer, a hole transport layer, a hole barrier layer, an electron barrier layer, an electron transport layer, and an electron injection layer. For example, a carrier injection layer (hole injection layer or electron injection layer) may also be formed as the common layer 114. Alternatively, the light-emitting device 130 may not include the common layer 114.

[0190] The uppermost light-emitting unit in the EL layer 113 (in this embodiment, the second light-emitting unit 113c) preferably includes a light-emitting layer and a carrier transport layer on the light-emitting layer. This prevents the light-emitting layer from being exposed to the outermost surface during the manufacturing process of the display device 100, thus reducing damage to the light-emitting layer. This improves the reliability of the light-emitting device.

[0191] The hole injection layer is a layer containing a material with high hole injection capability, into which holes are injected from the anode to the hole transport layer. Examples of materials with high hole injection capability include aromatic amine compounds and composite materials containing hole transport materials and acceptor materials (electron acceptor materials).

[0192] The hole transport layer is a layer that transports holes injected from the anode through the hole injection layer to the light-emitting layer. The hole transport layer is a layer containing a hole transport material. As a hole transport material, it is preferably a material having a hole mobility of 1×10-6 cm² / Vs or higher. In addition, any material other than the above can be used as long as its hole transportability is higher than its electron transportability. As a hole transport material, it is preferably a π-electron-rich heteroaromatic compound (e.g., carbazole derivatives, thiophene derivatives, furan derivatives, etc.) or an aromatic amine (a compound containing an aromatic amine skeleton) or a material with high hole transportability.

[0193] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light-emitting layer. The electron transport layer is a layer containing an electron transport material. As an electron transport material, it is preferably a substance having an electron mobility of 1×10-6 cm2 / Vs or higher. In addition, any substance other than the above can be used as long as its electron transportability is higher than that of electron transportability. As an electron transport material, metal complexes with a quinoline skeleton, metal complexes with a benzoquinoline skeleton, metal complexes with a chloroazole skeleton, metal complexes with a thiazole skeleton, etc., can be used. Substances with high electron transportability, such as chlorodiazole derivatives, triazole derivatives, imidazole derivatives, chloroazole derivatives, thiazole derivatives, phenobarbital derivatives, quinoline derivatives with quinoline ligands, benzoquinoline derivatives, quinoline derivatives, dibenzoquinoline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, nitrogen-containing heteroaromatic compounds, and other π-electron-deficient heteroaromatic compounds, can also be used.

[0194] The electron injection layer is a layer containing a material with high electron injection capability, through which electrons are injected from the cathode into the electron transport layer. As a material with high electron injection capability, alkali metals, alkaline earth metals, or compounds containing the above substances can be used. As a material with high electron injection capability, a composite material containing an electron transport material and a donor material (electron donor material) can also be used.

[0195] As the electron injection layer, for example, lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaFX, where X is any number), lithium 8-(hydroxyoxoline) (abbreviated as Liq), lithium 2-(2-pyridyl)phenol (abbreviated as LiPP), lithium 2-(2-pyridyl)-3-hydroxypyridinolato (abbreviated as LiPPy), lithium 4-phenyl-2-(2-pyridyl)phenol (abbreviated as LiPPP), lithium oxide (LiOx), or cesium carbonate, or other alkali metals, alkaline earth metals, or compounds thereof, can be used. Furthermore, the electron injection layer may also have a stacked structure of two or more layers. For example, a structure in which lithium fluoride is used as the first layer and ytterbium is provided as the second layer can be used.

[0196] Alternatively, an electron transport material can also be used as an electron injection layer. For example, a compound having a non-shared electron pair and an electron-deficient heteroaromatic ring can be used as an electron transport material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyrazine ring), and a triazine ring can be used.

[0197] The lowest unoccupied molecular orbital (LUMO) of organic compounds with non-shared electron pairs is preferably above -3.6 eV and below -2.3 eV. Generally, the highest occupied molecular orbital (HOMO) and LUMO levels of organic compounds can be estimated using cyclic voltammetry (CV), photoelectron spectroscopy, absorption spectroscopy, and inverse photoelectron spectroscopy.

[0198] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-di(naphthyl-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), diquinolinezo[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz) can be used in organic compounds with non-shared electron pairs. Furthermore, compared to BPhen, NBPhen has a high glass transition point (Tg), thus exhibiting high heat resistance.

[0199] Furthermore, in this embodiment, the light-emitting device 130 adopts a series structure. Therefore, a charge generation layer is provided between the two light-emitting units. The charge generation layer has at least a charge generation region. The charge generation layer has the function of injecting electrons into one of the two light-emitting units and injecting holes into the other when a voltage is applied between a pair of electrodes.

[0200] As described above, the charge generation layer has at least a charge generation region. The charge generation region preferably includes an acceptor material (electron acceptor material), for example, preferably including a hole transport material and an acceptor material that can be applied to the above-mentioned hole injection layer.

[0201] Furthermore, the charge generation layer preferably includes a layer containing a material with high electron injection capability. This layer can also be referred to as an electron injection buffer layer. The electron injection buffer layer is preferably disposed between the charge generation region and the electron transport layer. By providing an electron injection buffer layer, the injection energy barrier between the charge generation region and the electron transport layer can be mitigated, so electrons generated in the charge generation region can be easily injected into the electron transport layer.

[0202] The electron injection buffer layer preferably contains an alkali metal or an alkaline earth metal, for example, it may contain a compound of an alkali metal or an alkaline earth metal. Specifically, the electron injection buffer layer preferably contains an inorganic compound containing an alkali metal and oxygen or an inorganic compound containing an alkaline earth metal and oxygen, and more preferably contains an inorganic compound containing lithium and oxygen (lithium oxide (Li2O), etc.). In addition, materials applicable to the above-mentioned electron injection layers can be used as the electron injection buffer layer.

[0203] The charge-generating layer preferably includes a layer containing a material with high electron transport properties. This layer can also be referred to as an electron relay layer. The electron relay layer is preferably disposed between the charge-generating region and the electron injection buffer layer. When the charge-generating layer does not include an electron injection buffer layer, the electron relay layer is preferably disposed between the charge-generating region and the electron transport layer. The electron relay layer has the function of preventing the interaction between the charge-generating region and the electron injection buffer layer (or electron transport layer) and facilitating the transfer of electrons.

[0204] As an electronic relay layer, it is preferable to use phthalocyanine materials such as phthalocyanine bronze (II) (abbreviated as: CuPc) or metal complexes with metal-oxygen bonds and aromatic ligands.

[0205] Note that sometimes the above-mentioned charge generation region, electron injection buffer layer and electron relay layer cannot be clearly distinguished based on the cross-sectional shape or characteristics.

[0206] In addition, the charge generation layer may also include a donor material instead of an acceptor material. For example, the charge generation layer may also include a layer containing an electron transport material and a donor material that can be applied to the above-mentioned electron injection layer.

[0207] When stacking light-emitting units, by setting a charge generation layer between two light-emitting units, the rise of driving voltage can be suppressed.

[0208] [Example of a method for manufacturing a display device] Next, an example of a method for manufacturing a display device will be described using Figures 7 and 8. Cross-sectional views of the dashed lines A1-A2 and C1-C2 in Figure 1A are shown side by side in Figures 7A to 7D and Figures 8A to 8C.

[0209] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting display devices can be formed using sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), and ALD methods. CVD methods include plasma-enhanced chemical vapor deposition (PECVD) and thermal CVD. Furthermore, one type of thermal CVD method is metal-organic chemical vapor deposition (MOCVD).

[0210] In addition, the thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by methods such as spin coating, dip coating, spray coating, inkjet coating, distributor coating, screen printing, flatbed printing, doctor knife coating, slot coating, roller coating, curtain coating, and doctor knife coating.

[0211] In particular, when manufacturing light-emitting devices, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet printing can be used. Examples of vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam vapor deposition, molecular beam vapor deposition, and vacuum vapor deposition, as well as chemical vapor deposition (CVD). In particular, functional layers (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, etc.) included in the EL layer can be formed using methods such as vapor deposition (vacuum vapor deposition), coating methods (dip coating, dye coating, rod coating, spin coating, spray coating), and printing methods (inkjet printing, screen printing, offset printing, flexographic printing, photogravure printing, or micro-contact printing, etc.).

[0212] Furthermore, when processing the thin film constituting the display device, processing can be performed using methods such as photolithography. Additionally, the thin film can be processed using methods such as nanoimprinting, sandblasting, and peeling. Furthermore, island-shaped thin films can be directly formed using shadow masking methods such as metal masks.

[0213] Photolithography typically includes two methods. One method involves forming a photoresist mask on the thin film to be processed, processing the film by etching or the like, and then removing the photoresist mask. The other method involves forming a photosensitive thin film, exposing it, and developing it to process the film into the desired shape.

[0214] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm), or a mixture of these. Additionally, ultraviolet light, KrF laser, or ArF laser can also be used. Furthermore, immersion exposure can also be used. Additionally, extreme ultraviolet (EUV) light or X-rays can be used as the light for exposure. Furthermore, an electron beam can be used instead of the light for exposure. Extreme ultraviolet light, X-rays, or electron beams allow for extremely fine processing, making them preferable. Note that when exposure is performed by scanning with a beam such as an electron beam, a photomask is not required.

[0215] As a method for etching thin films, dry etching, wet etching and sandblasting can be used.

[0216] First, a pixel electrode 111 and a conductive layer 123 are formed on the layer 101 including the transistor (FIG. 7A). When forming the pixel electrode 111, sputtering or vacuum evaporation can be used, for example.

[0217] Next, an EL layer 113A (FIG. 7B) is formed on the pixel electrode 111 and on the layer 101 including the transistor.

[0218] As shown in FIG7B, in the cross-sectional view along the dotted line C1-C2, the EL layer 113A is not formed on the conductive layer 123. For example, by using a mask 191 to define the deposition area (to distinguish it from a high-precision metal mask, it is called a range mask or a coarse metal mask, etc.), the EL layer 113A can be deposited only in the desired area. In one embodiment of the present invention, a light-emitting device is formed using a photoresist mask, and by combining the above-mentioned area masks, the light-emitting device can be manufactured with a simpler process.

[0219] The EL layer 113A can be formed, for example, by vapor deposition, specifically by vacuum vapor deposition. Figure 7B shows a so-called facedown deposition method in which the substrate is inverted with the surface to be formed facing down.

[0220] In addition, the EL layer 113A can also be formed by transfer, printing, inkjet and coating methods.

[0221] Next, a sacrificial layer 118A, which will later become a sacrificial layer 118, and a sacrificial layer 119A, which will later become a sacrificial layer 119, are sequentially formed on the EL layer 113A and the conductive layer 123 (FIG. 7C). Sacrificial layers 118A and 119A are films with high resistance to the processing conditions of the EL layer 113A, specifically films with a large etch selectivity to the EL layer 113A.

[0222] When forming the sacrificial layers 118A and 119A, methods such as sputtering, ALD (including thermal ALD and PEALD), CVD, or vacuum evaporation can be used. Furthermore, the sacrificial layer 118A, formed in contact with the EL layer 113A, is preferably formed using a method that causes less damage to the EL layer 113A than the sacrificial layer 119A. For example, compared to sputtering, it is more preferable to form the sacrificial layer 118A using ALD or vacuum evaporation. Additionally, the sacrificial layers 118A and 119A are formed at a temperature lower than the heat resistance temperature of the EL layer 113A. The substrate temperature for forming the sacrificial layers 118A and 119A is typically 200°C or lower, preferably 150°C or lower, more preferably 120°C or lower, further preferably 100°C or lower, and even more preferably 80°C or lower.

[0223] It is preferable to use a film that can be removed by wet etching as the sacrificial layer 118A and sacrificial layer 119A. By using wet etching, the damage to the EL layer 113A during the processing of sacrificial layer 118A and sacrificial layer 119A can be reduced compared with the case of using dry etching.

[0224] In addition, the sacrificial layer 118A is preferably a film with a larger etch selectivity than the sacrificial layer 119A.

[0225] In the manufacturing method of the display device of this embodiment, it is preferable that the layers constituting the EL layer (hole injection layer, hole transport layer, light-emitting layer, active layer, and electron transport layer, etc.) are not easily processed during the processing of various sacrificial layers, and that the various sacrificial layers are not easily processed during the processing of each layer constituting the EL layer. It is preferable to select the material of the sacrificial layer, the processing method of the sacrificial layer, and the processing method of the EL layer with these conditions in mind.

[0226] Note that in this embodiment, an example is shown in which a sacrificial layer is formed by a two-layer structure of sacrificial layer 118A and sacrificial layer 119A, but the sacrificial layer may also have a single-layer structure or a stacked structure of three or more layers.

[0227] As sacrificial layers 118A and 119A, for example, metal films, alloy films, metal oxide films, semiconductor films, organic insulating films, and inorganic films such as inorganic insulating films can be used.

[0228] The sacrificial layers 118A and 119A can each 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 alloys containing such metallic materials. Low-melting-point materials such as aluminum or silver are particularly preferred. By using a metallic material capable of blocking ultraviolet light as one or both of the sacrificial layers 118A and 119A, ultraviolet light irradiation onto the EL layer can be suppressed, thereby suppressing the degradation of the EL layer, which is therefore preferable.

[0229] Alternatively, metal oxides such as In-Ga-Zn oxide can be used for sacrificial layers 118A and 119A. For example, an In-Ga-Zn oxide film can be formed using sputtering as sacrificial layer 118A or sacrificial layer 119A. Furthermore, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc., can be used. Alternatively, indium tin oxide containing silicon, etc., can also be used.

[0230] Note that element M (which is one or more of aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) can also be used to replace gallium.

[0231] Furthermore, various inorganic insulating films suitable for use in the protective layer 131 can be used as sacrificial layers 118A and 119A. In particular, oxide insulating films have higher adhesion to the EL layer than nitrided insulating films, which is preferable. For example, inorganic insulating materials such as alumina, hafnium oxide, and silicon oxide can be used for sacrificial layers 118A and 119A, respectively. As sacrificial layer 118A or sacrificial layer 119A, for example, an alumina film can be formed using the ALD method. By using the ALD method, damage to the substrate (especially the EL layer, etc.) can be reduced, which is preferable.

[0232] For example, an inorganic insulating film (e.g., an aluminum oxide film) formed using the ALD method can be used as the sacrificial layer 118A, and an inorganic film (e.g., an In-Ga-Zn oxide film, an aluminum film, or a tungsten film) formed using the sputtering method can be used as the sacrificial layer 119A.

[0233] Furthermore, the same inorganic insulating film can be used for both the sacrificial layer 118A and the subsequently formed insulating layer 125. For example, an alumina film formed using the ALD method can be used for both the sacrificial layer 118A and the insulating layer 125. Here, the sacrificial layer 118A and the insulating layer 125 can be formed under the same or different film-forming conditions. For example, by depositing the sacrificial layer 118A under the same conditions as the insulating layer 125, the sacrificial layer 118A can be formed as an insulating layer with high barrier properties against at least one of water and oxygen. On the other hand, since the sacrificial layer 118A is a layer that is mostly or entirely removed in subsequent processes, it is preferably easy to process. Therefore, the sacrificial layer 118A is preferably deposited under conditions where the substrate temperature during film formation is lower than that during film formation of the insulating layer 125.

[0234] Organic materials may also be used as one or both of the sacrificial layers 118A and 119A. For example, materials that are chemically stable in solvents that are at least chemically stable to the uppermost layer of the EL layer 113A may also be used as organic materials. In particular, materials soluble in water or alcohol may be suitable for use as one or both of the sacrificial layers 118A and 119A. When depositing the above-mentioned materials, it is preferable to apply the materials by the above-described wet film-forming method while the materials are dissolved in a solvent such as water or alcohol, and then perform a heat treatment to evaporate the solvent. At this time, it is preferable to perform the heat treatment under a reduced pressure atmosphere, thereby removing the solvent at a low temperature and for a short time, and reducing thermal damage to the EL layer.

[0235] When forming the sacrificial layer 118A and the sacrificial layer 119A, appropriate wet film-forming methods such as spin coating, dip coating, spray coating, inkjet coating, distributor coating, screen printing, flatbed printing, doctor blade coating, slot coating, roller coating, curtain coating, and doctor blade coating can be used.

[0236] Furthermore, sacrificial layer 118A and sacrificial layer 119A may each be made of organic resins such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, or polyamide resin soluble in alcohol. Additionally, fluorinated resins such as perfluoropolymers may also be used as sacrificial layer 118A and sacrificial layer 119A.

[0237] For example, as the sacrificial layer 118A, an organic film (e.g., a PVA film) formed by any one of the above-described wet film formation methods can be used, and as the sacrificial layer 119A, an inorganic film (e.g., a silicon nitride film) formed by sputtering can be used.

[0238] Next, a photoresist mask 190 (FIG. 7C) is formed on the sacrificial layer 119A. The photoresist mask 190 can be formed by coating a photosensitive resin (photoresist) and then exposing and developing it.

[0239] The photoresist mask can utilize either positive or negative photoresist materials.

[0240] The photoresist mask 190 is disposed at a position overlapping with the pixel electrode 111. Preferably, the photoresist mask 190 is provided with an island-shaped pattern in each sub-pixel.

[0241] Furthermore, the photoresist mask 190 is preferably disposed at a position overlapping with the conductive layer 123. This helps to prevent damage to the conductive layer 123 during the manufacturing process of the display device. Note that the photoresist mask 190 may also be omitted from the conductive layer 123.

[0242] Next, a portion of the sacrificial layer 119A is removed using a photoresist mask 190 to form a sacrificial layer 119 (FIG. 7D). The sacrificial layer 119 remains on the pixel electrode 111 and the conductive layer 123.

[0243] When etching the sacrificial layer 119A, it is preferable to use etching conditions with a high selectivity to prevent the sacrificial layer 118A from being removed before this etching. Furthermore, since the EL layer 113A is not exposed during the processing of the sacrificial layer 119A, the range of processing methods is wider compared to the case of processing the sacrificial layer 118A. Specifically, using an oxygen-containing gas as the etching gas during the processing of the sacrificial layer 119A can further suppress the degradation of the EL layer 113A.

[0244] Then, the photoresist mask 190 is removed. For example, the photoresist mask 190 can be removed by ashing using oxygen plasma. Alternatively, oxygen gas and noble gases (also known as rare gases) such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He can be used. Alternatively, the photoresist mask 190 can be removed by wet etching. At this time, the sacrificial layer 118A is located on the outermost surface and the EL layer 113A is not exposed, so damage to the EL layer 113A can be suppressed during the removal process of the photoresist mask 190. In addition, the range of selection methods for removing the photoresist mask 190 can be expanded.

[0245] Next, the sacrificial layer 119 is used as a mask (also known as a hard mask) to remove a portion of the sacrificial layer 118A to form the sacrificial layer 118 (Fig. 7D).

[0246] The sacrificial layer 118A and the sacrificial layer 119A can be processed by wet etching or dry etching, respectively. The processing of the sacrificial layer 118A and the sacrificial layer 119A is preferably carried out by anisotropic etching.

[0247] By using wet etching, compared with dry etching, damage to the EL layer 113A can be reduced during the processing of sacrificial layers 118A and 119A. When using wet etching, it is preferable to use a solution of developer, aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0248] Furthermore, when using the dry etching method, the degradation of the EL layer 113A can be suppressed by not using an oxygen-containing gas as the etching gas. When using the dry etching method, it is preferable to use a gas containing noble gases (also known as rare gases) such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3 or He as the etching gas.

[0249] For example, when using an alumina film formed by the ALD method as the sacrificial layer 118A, the sacrificial layer 118A can be processed by dry etching using CHF3 and He. Alternatively, when using an In-Ga-Zn oxide film formed by sputtering as the sacrificial layer 119A, the sacrificial layer 119A can be processed by wet etching using dilute phosphoric acid. Alternatively, it can be processed by dry etching using CH4 and Ar. Alternatively, the sacrificial layer 119A can be processed by wet etching using dilute phosphoric acid. Furthermore, when using a tungsten film formed by sputtering as the sacrificial layer 119A, the sacrificial layer 119A can be processed by dry etching using SF6, CF4, and O2, or CF4, Cl2, and O2.

[0250] Next, EL layer 113A is processed to form EL layer 113. For example, sacrificial layer 119 and sacrificial layer 118 are used as a hard mask to remove part of EL layer 113A to form EL layer 113 (FIG. 7D).

[0251] As shown in FIG7D, multiple EL layers 113 can be formed by processing EL layer 113A. In other words, EL layer 113A can be divided into multiple EL layers 113. Note that it is also possible not to divide EL layer 113A in either the row direction or the column direction. In this case, the shape of EL layer 113 can be ribbon-shaped.

[0252] The EL layer 113A is preferably processed by anisotropic etching. In particular, anisotropic dry etching is preferred. Alternatively, wet etching may also be used.

[0253] When using the dry etching method, the degradation of the EL layer 113A can be suppressed by not using an oxygen-containing gas as the etching gas.

[0254] Alternatively, an oxygen-containing gas can be used as the etching gas. When the etching gas contains oxygen, the etching rate can be increased. Therefore, etching can be performed under low power conditions while maintaining a sufficient etching rate. Thus, damage to the EL layer 113A can be suppressed. Furthermore, defects such as the adhesion of reaction products generated during etching can be suppressed.

[0255] When using dry etching, it is preferable to use one or more gases containing noble gases (also known as rare gases) such as H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, He, and Ar as the etching gas. Alternatively, it is preferable to use a gas containing one or more of the above gases and oxygen as the etching gas. Alternatively, oxygen gas may also 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. In addition, for example, a gas containing CF4, He, and oxygen can be used as the etching gas.

[0256] As described above, in one embodiment of the present invention, the sacrificial layer 119 is formed by forming a photoresist mask 190 on the sacrificial layer 119A and removing a portion of the sacrificial layer 119A using the photoresist mask 190. Then, the EL layer 113 is formed by removing a portion of the EL layer 113A using the sacrificial layer 119 as a hard mask. Therefore, it can be said that the EL layer 113 is formed by processing the EL layer 113A using photolithography. Alternatively, a portion of the EL layer 113A can be removed using the photoresist mask 190. Then, the photoresist mask 190 can also be removed.

[0257] By setting island-shaped EL layers 113 for each sub-pixel, leakage current between sub-pixels can be suppressed. This suppresses the degradation of display quality in the display device. Furthermore, high definition and high display quality in the display device can be achieved.

[0258] Next, an insulating film 125A (FIG. 8A) is formed to cover the pixel electrode 111, EL layer 113, sacrificial layer 118 and sacrificial layer 119, which will later become the insulating layer 125.

[0259] As the insulating film 125A, it is preferred, for example, to be an insulating film with a thickness of 3 nm or more, 5 nm or more, or 10 nm or more and 200 nm or less, 150 nm or less, 100 nm or less, or 120 °C or more and 200 nm or less, 180 nm or less, 160 nm or less, 150 nm or less, or 50 nm or less, formed under conditions where the substrate temperature is 60 °C or more, 80 °C or more, 100 °C or more and 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less.

[0260] As an insulating film 125A, it is preferably an aluminum oxide film formed by the ALD method.

[0261] Next, an insulating film 127A (FIG. 8A) is formed on the insulating film 125A. The insulating film 127A can be made of a photosensitive material, such as a photosensitive resin. The insulating film 127A can be formed using wet film-forming methods such as spin coating, dip coating, spray coating, inkjet coating, dispensing, screen printing, offset printing, doctor blade coating, slot coating, roller coating, curtain coating, and doctor blade coating. In particular, it is preferable to form the insulating layer 127 by spin coating.

[0262] The insulating films 125A and 127A are preferably deposited using a formation method that causes less damage to the EL layer 113. In particular, since the insulating film 125A is formed in a manner that makes side contact with the EL layer 113, it is preferable to deposit it using a formation method that causes less damage to the EL layer 113 compared to the insulating film 127A. Furthermore, the insulating films 125A and 127A are each formed at a temperature lower than the heat resistance temperature of the EL layer 113. The substrate temperature during the formation of the insulating films 125A and 127A is typically 200°C or lower, preferably 180°C or lower, more preferably 160°C or lower, further preferably 150°C or lower, and even more preferably 140°C or lower. For example, the insulating film 125A can be formed using the ALD method. The ALD method reduces film formation damage and allows for the deposition of films with high coverage, making it preferable.

[0263] Next, the insulating film 127A is processed to form the insulating layer 127 (FIG. 8B). For example, when a photosensitive material is used for the insulating film 127A, the insulating layer 127 can be formed by exposing and developing the insulating film 127A. Alternatively, etching can be performed to adjust the surface height of the insulating layer 127. The insulating layer 127 can also be processed, for example, by ashing using oxygen plasma.

[0264] Next, at least a portion of the insulating film 125A is removed to form an insulating layer 125 (Fig. 8B).

[0265] The insulating film 125A is preferably processed by dry etching. The processing of the insulating film 125A is preferably performed by anisotropic etching. The insulating film 125A can be processed using the etching gas that can be used when processing the sacrificial layer.

[0266] Then, sacrificial layer 119 and sacrificial layer 118 are removed. As a result, at least a portion of the top surface of EL layer 113 and the top surface of conductive layer 123 is exposed.

[0267] The sacrificial layer is preferably removed by wet etching. This reduces damage to the EL layer 113 during sacrificial layer removal, for example, compared to removing the sacrificial layer by dry etching.

[0268] Alternatively, the sacrificial layer can be removed by dissolving it in a solvent such as water or alcohol. Examples of alcohols include ethanol, methanol, isopropanol (IPA), or glycerol.

[0269] After removing the sacrificial layer, a drying process can also be performed to remove water contained in the EL layer and water adhering to the surface of the EL layer. For example, a heating process can be performed in an inactive gas atmosphere or a reduced pressure atmosphere. The heating process can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 120°C or lower. By using a reduced pressure atmosphere, drying can be performed at a lower temperature, which is preferable.

[0270] Next, a common layer 114 is formed on the insulating layer 125, the insulating layer 127, and the EL layer 113. Then, a common electrode 115 is formed on the common layer 114 (FIG. 8C).

[0271] The common layer 114 can be formed by methods such as vapor deposition (including vacuum vapor deposition), transfer printing, printing, inkjet printing, and coating. As described above, the common layer 114 may include, for example, an electron injection layer or a hole injection layer.

[0272] The common electrode 115 is formed, for example, by sputtering or vacuum evaporation. Alternatively, a film formed by evaporation and a film formed by sputtering may be laminated.

[0273] Then, a protective layer 131 is formed on the common electrode 115, and color layers 132R, 132G, and 132B are formed on the protective layer 131 (FIG. 8C). Furthermore, a substrate 120 is bonded to the protective layer 131 and the color layers using a resin layer 122, thereby manufacturing the display device 100 shown in FIG. 1B and FIG. 2C.

[0274] Examples of methods for forming the protective layer 131 include vacuum evaporation, sputtering, CVD, and ALD. Additionally, the protective layer 131 may have a single-layer structure or a multilayer structure.

[0275] [Pixel Layout] The following mainly describes the pixel layout that differs from that in Figure 1A. There are no particular restrictions on the arrangement of subpixels, and various arrangement methods can be used. Examples of subpixel arrangements include stripe arrangement, S-stripe arrangement, matrix arrangement, Delta arrangement, Bayer arrangement, Pentile arrangement, etc.

[0276] Furthermore, examples of the top surface shape of a sub-pixel include triangles, quadrilaterals (including rectangles and squares), pentagons, and other polygonal shapes with rounded corners, as well as ellipses or circles. Here, the top surface shape of the sub-pixel corresponds to the top surface shape of the light-emitting area of ​​the light-emitting device.

[0277] Pixel 110 shown in Figure 9A uses an S-striped arrangement. Pixel 110 shown in Figure 9A is composed of three sub-pixels: sub-pixels 110a, 110b, and 110c. For example, as shown in Figure 11A, sub-pixel 110a can also be used as the blue sub-pixel B, sub-pixel 110b as the red sub-pixel R, and sub-pixel 110c as the green sub-pixel G.

[0278] The pixel 110 shown in FIG9B includes a sub-pixel 110a with a top surface shape that is approximately trapezoidal and has rounded corners, a sub-pixel 110b with a top surface shape that is approximately triangular and has rounded corners, and a sub-pixel 110c with a top surface shape that is approximately quadrilateral or hexagonal and has rounded corners. Furthermore, the light-emitting area of ​​sub-pixel 110a is larger than that of sub-pixel 110b. Thus, the shape and size of each sub-pixel can be determined independently. For example, the higher the reliability of the light-emitting device included in the sub-pixel, the smaller the size of that sub-pixel can be. For example, as shown in FIG11B, sub-pixel 110a can be used as a green sub-pixel G, sub-pixel 110b as a red sub-pixel R, and sub-pixel 110c as a blue sub-pixel B.

[0279] Pixels 124a and 124b shown in FIG9C are arranged in a Pentile pattern. In the example shown in FIG9C, pixel 124a, which includes sub-pixels 110a and 110b, and pixel 124b, which includes sub-pixels 110b and 110c, are alternately configured. For example, as shown in FIG11C, sub-pixel 110a can also be used as a red sub-pixel R, sub-pixel 110b can be used as a green sub-pixel G, and sub-pixel 110c can be used as a blue sub-pixel B.

[0280] Pixels 124a and 124b shown in Figures 9D and 9E are arranged in a Delta configuration. Pixel 124a includes two sub-pixels (sub-pixels 110a and 110b) in the upper row (first row) and one sub-pixel (sub-pixel 110c) in the lower row (second row). Pixel 124b includes one sub-pixel (sub-pixel 110c) in the upper row (first row) and two sub-pixels (sub-pixels 110a and 110b) in the lower row (second row). For example, as shown in Figure 11D, sub-pixel 110a can also be used as the red sub-pixel R, sub-pixel 110b as the green sub-pixel G, and sub-pixel 110c as the blue sub-pixel B.

[0281] Figure 9D is an example of an approximately quadrilateral top surface shape with rounded corners for each sub-pixel, and Figure 9E is an example of a circular top surface shape for each sub-pixel.

[0282] Figure 9F shows an example of subpixels of each color configured in a zigzag shape. Specifically, when viewed from above, the upper positions of two subpixels arranged in the column direction (e.g., subpixels 110a and 110b, or subpixels 110b and 110c) are offset. For example, as shown in Figure 11E, subpixel 110a can also be used as the red subpixel R, subpixel 110b as the green subpixel G, and subpixel 110c as the blue subpixel B.

[0283] In photolithography, the finer the pattern being processed, the more significant the effect of light diffraction becomes. Therefore, when transferring the pattern from the photomask through exposure, its fidelity deteriorates, making it difficult to process the photomask into the desired shape. Consequently, even if the photomask pattern is rectangular, it is easy to form a pattern with rounded corners. Therefore, the top surface shape of a subpixel sometimes takes the form of a polygon with rounded corners, an ellipse, or a circle.

[0284] Furthermore, in a method for manufacturing a display device according to one embodiment of the present invention, the EL layer is processed into an island shape using a photoresist mask. The photoresist 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 photoresist material, the photoresist film is sometimes not sufficiently cured. The insufficiently cured photoresist film sometimes takes on a shape far from the desired shape during processing. As a result, the top surface shape of the EL layer is sometimes a polygonal shape with rounded corners, an ellipse, or a circle, etc. For example, when a photoresist mask with a square top surface shape is to be formed, sometimes a photoresist mask with a circular top surface shape is formed and the top surface shape of the EL layer is circular.

[0285] In order to make the top surface shape of the EL layer the desired shape, a technique for correcting the mask pattern in advance by making the design pattern consistent with the transfer pattern (OPC (Optical Proximity Correction) technique) can also be used. Specifically, in the OPC technique, correction patterns are added to the corners of the pattern on the mask pattern.

[0286] In addition, there is no restriction on the arrangement order of the sub-pixels in the pixel 110 with the stripe arrangement shown in FIG1A. For example, as shown in FIG11F, they can also be arranged in the order of green sub-pixel G, red sub-pixel R, and blue sub-pixel B.

[0287] As shown in Figures 10A to 10H, a pixel may include four types of sub-pixels.

[0288] Pixels 110 shown in Figures 10A to 10C are arranged in stripes.

[0289] Figure 10A shows an example of a top surface shape where each sub-pixel has a rectangular shape, Figure 10B shows an example of a top surface shape where each sub-pixel has a top surface shape that connects two semicircles and a rectangle, and Figure 10C shows an example of a top surface shape where each sub-pixel has an oval shape.

[0290] Pixels 110 shown in Figures 10D to 10F are arranged in a matrix.

[0291] Figure 10D shows an example of a top surface shape where each sub-pixel has a square shape, Figure 10E shows an example of a top surface shape where each sub-pixel has a roughly square shape at the corners, and Figure 10F shows an example of a top surface shape where each sub-pixel has a circular shape.

[0292] Figures 10G and 10H show an example of a pixel 110 composed of two rows and three columns.

[0293] As shown in Figure 10G, pixel 110 includes three sub-pixels (sub-pixels 110a, 110b, and 110c) in the upper row (first row) and one sub-pixel (sub-pixel 110d) in the lower row (second row). In other words, pixel 110 includes sub-pixel 110a in the left column (first column), sub-pixel 110b in the middle column (second column), sub-pixel 110c in the right column (third column), and sub-pixel 110d across these three columns.

[0294] As shown in FIG10H, pixel 110 includes three sub-pixels (sub-pixels 110a, 110b, and 110c) in the upper row (first row) and three sub-pixels 110d in the lower row (second row). In other words, pixel 110 includes sub-pixels 110a and 110d in the left column (first column), sub-pixels 110b and 110d in the middle column (second column), and sub-pixels 110c and 110d in the right column (third column). As shown in FIG10H, by aligning the sub-pixel configuration of the upper and lower rows, waste that may be generated during the manufacturing process can be efficiently removed. Thus, a display device with high display quality can be provided.

[0295] The pixel 110 shown in Figures 10A to 10H is composed of four sub-pixels: sub-pixels 110a, 110b, 110c, and 110d. Each of the sub-pixels 110a, 110b, 110c, and 110d includes 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); etc. For example, as shown in Figures 11G to 11J, sub-pixels 110a, 110b, 110c, and 110d can be red, green, blue, and white sub-pixels, respectively.

[0296] As described above, in a display device according to one embodiment of the present invention, various layouts can be adopted for pixels composed of sub-pixels including light-emitting devices.

[0297] Thus, in the manufacturing method of the display device of this embodiment, the island-shaped EL layer is not formed using a metal mask including a highly fine pattern, but is formed by depositing an EL layer on the entire surface and then processing it. Therefore, the size of the island-shaped EL layer can be made smaller than that formed using a metal mask. Therefore, a high-definition display device or a display device with a high aperture ratio, which has been difficult to achieve until now, can be realized.

[0298] One embodiment of the display device of the present invention includes light-emitting devices employing a series structure, which makes it easy to adjust carrier balance and prevents color change between low-brightness and high-brightness light emission. Furthermore, by providing island-shaped EL layers for each sub-pixel, leakage current between sub-pixels can be suppressed. This suppresses the degradation of display quality. Additionally, high definition and high display quality of the display device can be achieved.

[0299] This embodiment can be appropriately combined with other embodiments. Furthermore, in this specification, where multiple structural examples are shown in one embodiment, these structural examples can be appropriately combined.

[0300] Embodiment 2 In this embodiment, a display device according to an embodiment of the present invention will be described using Figures 12 to 15.

[0301] 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 as a display unit for devices such as: electronic devices with large screens, such as televisions, desktop or laptop computers, monitors for computers, digital signage, large game consoles such as pinball machines, etc.; digital cameras; digital video cameras; digital photo frames; mobile phones; portable game consoles; portable information terminals; and audio playback devices.

[0302] In the display device of this embodiment, the light-emitting devices adopt a series structure, so the chromaticity change between low-brightness and high-brightness light emission is small. Furthermore, in the display device of this embodiment, the EL layer in each light-emitting device is separated, so crosstalk between adjacent sub-pixels is suppressed. Therefore, a display device with high display quality can be realized.

[0303] [Display Device 100A] FIG12 is a perspective view of display device 100A, and FIG13A is a cross-sectional view of display device 100A.

[0304] The display device 100A has a structure in which substrate 152 and substrate 151 are bonded together. Substrate 152 is shown in dashed lines in FIG12.

[0305] The display device 100A includes a display section 162, a connection section 140, a circuit 164, wiring 165, etc. Figure 12 shows an example of the display device 100A with IC 173 and FPC 172 installed. Therefore, it can also be said that the structure shown in Figure 12 is a display module including the display device 100A, IC (integrated circuit) and FPC.

[0306] The connecting portion 140 is provided on the outer side of the display portion 162. The connecting portion 140 may be provided along one or more sides of the display portion 162. The number of connecting portions 140 may be one or more. Figure 12 shows an example in which the connecting portions 140 are provided around the four sides of the display portion. In the connecting portion 140, the common electrode of the light-emitting device is electrically connected to the conductive layer, and power can be supplied to the common electrode.

[0307] As circuit 164, for example, a scan line drive circuit can be used.

[0308] Wiring 165 has the function of supplying signals and power to display unit 162 and circuit 164. The signals and power are input to wiring 165 from the outside via FPC 172 or from IC 173.

[0309] Figure 12 shows an example of IC 173 being mounted on substrate 151 using COG or COF methods. IC 173 can be, for example, an IC including scan line drive circuitry or signal line drive circuitry. Note that the display device 100A and the display module do not necessarily need to have an IC mounted on them. Alternatively, the IC can also be mounted on an FPC using COF methods.

[0310] FIG13A shows an example of a cross-section of a portion of the display device 100A including a portion of the area of ​​FPC 172, a portion of the circuit 164, a portion of the display portion 162, a portion of the connection portion 140, and a portion of the area including the end.

[0311] The display device 100A shown in FIG. 13A includes transistors 201 and 205, a light-emitting device 130, a color layer 132R that transmits red light, a color layer 132G that transmits green light, and a color layer 132B that transmits blue light, between substrates 151 and 152. The light-emitting device 130 may have a structure that emits white light. The light emitted by the light-emitting device 130 overlapping with the color layer 132R is extracted as red light through the color layer 132R and is emitted to the outside of the display device 100A. Similarly, the light emitted by the light-emitting device 130 overlapping with the color layer 132G is extracted as green light through the color layer 132G and is emitted to the outside of the display device 100A. In addition, the light emitted by the light-emitting device 130 overlapping with the color layer 132B is extracted as blue light through the color layer 132B and is emitted to the outside of the display device 100A.

[0312] The display device 100A may adopt the pixel layout shown in Embodiment 1.

[0313] The light-emitting devices included in each sub-pixel that emits light of each color have the same structure; for example, they can all adopt a structure that emits white light. Specifically, the EL layer 113 included in each light-emitting device can have the same structure. On the other hand, since the EL layer 113 included in each light-emitting device is separated, leakage current between the light-emitting devices can be suppressed. As a result, the display quality of the display device can be improved.

[0314] Except for the different structure of the pixel electrode, the light-emitting device 130 has the same structure as the stacked structure shown in FIG1B. For details of the light-emitting device 130, please refer to Embodiment 1.

[0315] The light-emitting device 130 includes a conductive layer 126 and a conductive layer 129 on the conductive layer 126. One or both of the conductive layer 126 and the conductive layer 129 may be referred to as a pixel electrode.

[0316] The conductive layer 126 is connected to the conductive layer 222b included in the transistor 205 through an opening provided in the insulating layer 214. In the display device 100A, the ends of the conductive layer 126 are aligned or substantially aligned with the ends of the conductive layer 129, but are not limited thereto. For example, the conductive layer 129 may also be provided in a manner that covers the ends of the conductive layer 126. The conductive layers 126 and 129 preferably each include a conductive layer used as a reflective electrode. Furthermore, one or both of the conductive layers 126 and 129 may also include a conductive layer used as a transparent electrode.

[0317] The conductive layer 126 is provided in such a way that it covers the opening provided in the insulating layer 214. The recess of the conductive layer 126 is filled with layer 128.

[0318] Layer 128 has the function of planarizing the recesses of conductive layer 126. A conductive layer 129 electrically connected to conductive layer 126 is provided on conductive layer 126 and layer 128. Therefore, the area overlapping with the recesses of conductive layer 126 can also be used as a light-emitting area, thereby improving the aperture ratio of the pixel.

[0319] Layer 128 can be either an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be appropriately used as layer 128. In particular, layer 128 is preferably formed using an insulating material.

[0320] As layer 128, an insulating layer containing organic materials can be suitable. For example, acrylic resin, polyimide resin, epoxy resin, polyimide resin, polyimide-polyamide resin, silicone resin, benzocyclobutene resin, phenolic resin, and precursors of the above resins can be used as layer 128. Alternatively, a photosensitive resin can also be used as layer 128. The photosensitive resin can be a positive or negative material.

[0321] By using a photosensitive resin, layer 128 can be manufactured using only an exposure and development process, thereby reducing the impact of dry etching or wet etching on the surface of conductive layer 126. In addition, by using a negative photosensitive resin to form layer 128, sometimes the same photomask forming layer 128 used when forming the opening of insulating layer 214 can be used.

[0322] The top surface of the conductive layer 129 is covered by the EL layer 113. When viewed from above, the entire overlapping area of ​​the conductive layer 129 and the EL layer 113 can be used as the light-emitting area of ​​the light-emitting device 130, thus improving the pixel aperture ratio. Additionally, the EL layer 113 may also cover at least a portion of the side surface of the conductive layer 129. Furthermore, the EL layer 113 may also cover only a portion of the top surface of the conductive layer 129. In other words, a portion of the top surface of the conductive layer 129 may not be covered by the EL layer 113.

[0323] The side of the EL layer 113 is covered by the insulating layer 125 and overlaps with the insulating layer 127 through the insulating layer 125. A common layer 114 is provided on the EL layer 113, the insulating layer 125 and the insulating layer 127, and a common electrode 115 is provided on the common layer 114. The common layer 114 and the common electrode 115 are both continuous films used by multiple light-emitting devices.

[0324] In addition, a protective layer 131 is provided on the light-emitting device 130. By forming a protective layer 131 covering the light-emitting device, impurities such as water can be prevented from entering the light-emitting device, thereby improving the reliability of the light-emitting device.

[0325] The protective layer 131 and the substrate 152 are bonded together by the adhesive layer 142. A solid sealing structure or a hollow sealing structure can be used as the seal for the light-emitting device. In FIG. 13A, the space between the substrate 152 and the substrate 151 is filled by the adhesive layer 142, employing a solid sealing structure. Alternatively, a hollow sealing structure can be used, where the space is filled with an inactive gas (nitrogen or argon, etc.). In this case, the adhesive layer 142 can also be arranged in a manner that does not overlap with the light-emitting device. Furthermore, a resin different from that used in the frame-shaped adhesive layer can be used to fill the space.

[0326] In the connecting portion 140, a conductive layer 123 is provided on the insulating layer 214. An example is shown here where the conductive layer 123 has a laminated structure having a conductive film processed with the same conductive film as the conductive layer 126 and a conductive film processed with the same conductive film as the conductive layer 129. The side surface of the conductive layer 123 is covered by the insulating layer 125 and overlaps with the insulating layer 127 through the insulating layer 125. Furthermore, 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 through the common layer 114. Alternatively, the connecting portion 140 may not have a common layer 114. In this case, the conductive layer 123 and the common electrode 115 are in direct contact and electrically connected.

[0327] The display device 100A has a top-emitting structure. Light emitted from the light-emitting device is emitted to one side of the substrate 152. The substrate 152 is preferably made of a material with high transmittance to visible light.

[0328] The pixel electrode contains a material that reflects visible light, and the opposite electrode (common electrode 115) contains a material that transmits visible light.

[0329] The stacked structure of substrate 151 to insulating layer 214 corresponds to layer 101 with transistor in embodiment 1.

[0330] Transistors 201 and 205 are both disposed on substrate 151. These transistors can be formed using the same material and the same process.

[0331] Insulating layers 211, 213, 215, and 214 are sequentially disposed on substrate 151. A portion of insulating layer 211 serves as a gate insulating layer for each transistor. A portion of insulating layer 213 serves as a gate insulating layer for each transistor. Insulating layer 215 is disposed to cover the transistor. Insulating layer 214 is disposed to cover the transistor and serves as a planarization layer. Furthermore, there is no particular limitation on the number of gate insulating layers and the number of insulating layers covering the transistor; there can be one or more.

[0332] Preferably, at least one of the insulating layers covering the transistor is made of a material that does not readily diffuse impurities such as water and hydrogen. This allows the insulating layer to function as a barrier layer. By employing this structure, the diffusion of impurities from the outside into the transistor can be effectively suppressed, thereby improving the reliability of the display device.

[0333] Inorganic insulating films are preferably used as insulating layers 211, 213, and 215. Examples of inorganic insulating films include silicon nitride films, silicon oxynitride films, silicon oxide films, silicon oxynitride films, aluminum oxide films, and aluminum nitride films. Additionally, hafnium oxide films, yttrium oxide films, zirconium oxide films, gallium oxide films, tantalum oxide films, magnesium oxide films, lanthanum oxide films, cerium oxide films, and neodymium oxide films can also be used. Furthermore, two or more of the above-mentioned insulating films can be laminated.

[0334] The insulating layer 214, used as a planarization layer, is preferably an organic insulating layer. Materials suitable for use as organic insulating layers include, for example, acrylic resin, polyimide resin, epoxy resin, polyimide resin, polyimide-polyamide resin, silicone resin, benzocyclobutene resin, phenolic resin, and precursors of these resins. Alternatively, the insulating layer 214 may also employ a laminated structure of an organic insulating layer and an inorganic insulating film. The outermost layer of the insulating layer 214 is preferably used as an etching protective film. This suppresses the formation of recesses in the insulating layer 214 during the processing of the conductive layer 126 or conductive layer 129. Alternatively, the insulating layer 214 may also have recesses during the processing of the conductive layer 126 or conductive layer 129.

[0335] Transistors 201 and 205 include: a conductive layer 221 serving as a gate; an insulating layer 211 serving as a gate insulating layer; conductive layers 222a and 222b serving as a source and drain; a semiconductor layer 231; an insulating layer 213 serving as a gate insulating layer; and a conductive layer 223 serving as a gate. Here, the multiple layers obtained by processing the same conductive film are given the same shaded lines. 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.

[0336] There are no particular limitations on the structure of the transistors included in the display device of this embodiment. For example, planar transistors, interleaved transistors, or anti-interleaved transistors can be used as the transistor structure. Furthermore, top-gate or bottom-gate transistor structures can also be used. Alternatively, gates can be provided above and below the semiconductor layer forming the channel.

[0337] Transistors 201 and 205 employ a structure in which a semiconductor layer forming a channel is sandwiched between two gates. Alternatively, the two gates can be connected, and the transistor can be driven by supplying the same signal to both gates. Or, the critical voltage of the transistor can be controlled by applying a potential to one of the two gates to control the critical voltage and applying a potential to the other to drive it.

[0338] There are no particular restrictions on the crystallinity of the semiconductor material used for the transistor. Amorphous semiconductors, single-crystal semiconductors, or semiconductors with crystallinity other than single crystals (microcrystalline semiconductors, polycrystalline semiconductors, or semiconductors with a portion of crystalline regions) can be used. When using single-crystal semiconductors or semiconductors with crystallinity, the degradation of transistor characteristics can be suppressed, so it is preferable.

[0339] The semiconductor layer of the transistor is preferably made of metal oxide (also known as oxide semiconductor). That is, the display device of this embodiment preferably uses a transistor (hereinafter, OS transistor) that contains metal oxide in the channel forming region.

[0340] As crystalline oxide semiconductors, examples include CAAC (c-axis-aligned crystalline)-OS and nc (nanocrystalline)-OS.

[0341] Alternatively, a transistor (Si transistor) in which silicon is used in the channel formation region can also be used. Examples of silicon include monocrystalline silicon, polycrystalline silicon, and amorphous silicon. In particular, a transistor containing low-temperature polycrystalline silicon (LTPS) in the semiconductor layer (hereinafter also referred to as LTPS transistor) can be used. LTPS transistors have high field-effect mobility and good frequency characteristics.

[0342] By using Si transistors such as LTPS transistors, circuits that require high-frequency driving (e.g., source driver circuits) and display sections can be formed on the same substrate. Therefore, the external circuits mounted to the display device can be simplified, and component costs and installation costs can be reduced.

[0343] Compared to transistors using amorphous silicon, OS transistors have a very high field-effect mobility. Furthermore, the leakage current between the source and drain of an OS transistor in the off state (hereinafter also referred to as off-state current) is extremely low, allowing the charge stored in the capacitor connected in series with the transistor to be maintained for extended periods. Additionally, by using OS transistors, the power consumption of the display device can be reduced.

[0344] Furthermore, the off-state current of an OS transistor with a channel width of 1 μm at room temperature can be less than 1aA (1×10⁻¹⁸ A), less than 1zA (1×10⁻²¹ A), or less than 1yA (1×10⁻²⁴ A). Note that the off-state current of a Si transistor with a channel width of 1 μm at room temperature is greater than or equal to 1fA (1×10⁻¹⁵ A) and less than 1pA (1×10⁻¹² A). Therefore, it can also be said that the off-state current of an OS transistor is about 10 bits lower than that of a Si transistor.

[0345] Furthermore, when increasing the luminous brightness of the light-emitting device included in the pixel circuit, it is necessary to increase the current flowing through the light-emitting device. For this purpose, it is necessary to increase the source-drain voltage of the driving transistor included in the pixel circuit. Because the source-drain breakdown voltage of an OS transistor is higher than that of a Si transistor, a high voltage can be applied between the source and drain of the OS transistor. Therefore, by using an OS transistor as the driving transistor included in the pixel circuit, the current flowing through the light-emitting device can be increased, thereby improving the luminous brightness of the light-emitting device.

[0346] Furthermore, when the transistor operates in the saturation region, compared to a Si transistor, an OS transistor can minimize the change in source-drain current as the gate-source voltage changes. Therefore, by using an OS transistor as the driving transistor included in the pixel circuit, the current flowing through the source-drain can be precisely determined based on the change in the gate-source voltage, thus controlling the amount of current flowing through the light-emitting device. This allows for an increase in the grayscale level of the pixel circuit.

[0347] Furthermore, regarding the saturation characteristics of the current flowing through a transistor when it operates in the saturation region, compared to Si transistors, OS transistors can maintain a stable current (saturation current) even when the source-drain voltage is gradually increased. Therefore, by using OS transistors as driving transistors, even if the current-voltage characteristics of, for example, EL devices become non-uniform, a stable current can flow through the light-emitting device. In other words, when an OS transistor operates in the saturation region, the source-drain current remains almost unchanged even when the source-drain voltage is increased, thus stabilizing the luminous brightness of the light-emitting device.

[0348] As described above, by using an OS transistor as the driving transistor included in the pixel circuit, it is possible to achieve "suppression of black blur", "increase in light emission brightness", "multi-grayscale conversion", "suppression of non-uniformity of light emission devices", etc.

[0349] For example, the metal oxide used for the semiconductor layer preferably comprises indium, M (M is selected from one or more of 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 selected from one or more of aluminum, gallium, yttrium, and tin.

[0350] In particular, as the semiconductor layer, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also denoted as IGZO). 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 denoted as IAZO). Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), gallium (Ga), and zinc (Zn) (also denoted as IAGZO).

[0351] When using In-M-Zn oxide in a semiconductor layer, the number of In atoms in the In-M-Zn oxide is preferably greater than or equal to the number of M atoms. Examples of the metal element atomic ratios in the aforementioned In-M-Zn oxide include: In:M:Zn = 1:1:1 or a similar ratio; In:M:Zn = 1:1:1.2 or a similar ratio; In:M:Zn = 1:3:2 or a similar ratio; In:M:Zn = 1:3:4 or a similar ratio; In:M:Zn = 2:1:3 or a similar ratio; In:M:Zn = 3:1:2 or a similar ratio; In:M:Zn = 4 ... Compositions with n=4:2:3 or similar, In:M:Zn=4:2:4.1 or similar, In:M:Zn=5:1:3 or similar, In:M:Zn=5:1:6 or similar, In:M:Zn=5:1:7 or similar, In:M:Zn=5:1:8 or similar, In:M:Zn=6:1:6 or similar, In:M:Zn=5:2:5 or similar, etc. Note that "similar" composition includes a range of ±30% of the desired atomic number ratio.

[0352] For example, when the atomic number ratio is described as In:Ga:Zn = 4:2:3 or a similar composition, the following cases are included: when In is 4, Ga is 1 or more and 3 or less, and Zn is 2 or more and 4 or less. Furthermore, when the atomic number ratio is described as In:Ga:Zn = 5:1:6 or a similar composition, the following cases are included: when In is 5, Ga is greater than 0.1 and 2 or less, and Zn is 5 or more and 7 or less. Furthermore, when the atomic number ratio is described as In:Ga:Zn = 1:1:1 or a similar composition, the following cases are included: when In is 1, Ga is greater than 0.1 and 2 or less, and Zn is greater than 0.1 and 2 or less.

[0353] The transistors included in circuit 164 and the transistors included in display unit 162 may have the same structure or different structures. The multiple transistors included in circuit 164 may have the same structure or two or more different structures. Similarly, the multiple transistors included in display unit 162 may have the same structure or two or more different structures.

[0354] Alternatively, all transistors included in the display unit 162 may be OS transistors, all transistors included in the display unit 162 may be Si transistors, OS transistors may be used as part of the transistors included in the display unit 162 and Si transistors may be used as other transistors.

[0355] 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, the structure combining LTPS transistors and OS transistors is sometimes referred to as LTPO. As a more suitable example, it is preferable to use OS transistors as switches to control the conduction and non-conduction between wirings and LTPS transistors as transistors to control current.

[0356] For example, one of the transistors included in the display unit 162 is used as a transistor for controlling the current flowing through the light-emitting device and may also be called a driving transistor. One of the source and drain electrodes of the driving transistor is electrically connected to the pixel electrode of the light-emitting device. Preferably, an LTPS transistor is used as the driving transistor. As a result, the current flowing through the light-emitting device in the pixel circuit can be increased.

[0357] On the other hand, another transistor included in the display unit 162 is used as a switch for controlling the selection and non-selection of pixels and may also be referred to as 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 as the selection transistor. As a result, the grayscale of the pixels can be maintained even when the frame rate is greatly reduced (e.g., less than 1 fps), thereby reducing power consumption by stopping the driver when displaying static images.

[0358] As described above, the display device of one embodiment of the present invention can have a high aperture ratio, high definition, high display quality and low power consumption.

[0359] A display device according to one embodiment of the present invention has a structure including an OS transistor and a light-emitting device having an MML (Metal Mask Less) structure. By employing this structure, the leakage current flowing through the transistor and the leakage current flowing between adjacent light-emitting devices (also referred to as lateral leakage current, side leakage current, etc.) can be extremely low. In addition, by employing the above structure, when an image is displayed on the display device, the viewer can observe one or more of the following: image sharpness, image sharpness, high color saturation, and high contrast. Furthermore, by employing a structure with extremely low leakage current flowing through the transistor and extremely low lateral leakage current between light-emitting devices, display with minimal light leakage, which can occur when displaying black, is possible.

[0360] Figures 13B and 13C show other examples of transistor structures.

[0361] Transistors 209 and 210 include: a conductive layer 221 serving as a gate; an insulating layer 211 serving as a gate insulating layer; a semiconductor layer 231 including 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 serving as a gate insulating layer; a conductive layer 223 serving 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 also be provided.

[0362] In the example shown in FIG13B, in transistor 209, insulating layer 225 covers the top and side surfaces of semiconductor layer 231. Conductive layers 222a and 222b are connected to low-resistance region 231n through openings provided in insulating layers 225 and 215. One of conductive layers 222a and 222b is used as a source and the other is used as a drain.

[0363] On the other hand, in the transistor 210 shown in FIG13C, the insulating layer 225 overlaps with the channel forming region 231i of the semiconductor layer 231 but does not overlap with the low resistance region 231n. For example, the structure shown in FIG13C can be formed by processing the insulating layer 225 with the conductive layer 223 as a mask. In FIG13C, the insulating layer 215 covers the insulating layer 225 and the conductive layer 223, and the conductive layers 222a and 222b are respectively connected to the low resistance region 231n through the opening of the insulating layer 215.

[0364] A connection portion 204 is provided in a region of the substrate 151 that does not overlap with the substrate 152. In the connection portion 204, wiring 165 is electrically connected to the FPC 172 through the conductive layer 166 and the connection layer 242. The conductive layer 166 has a laminated structure of a conductive film obtained by processing the same conductive film as the conductive layer 126 and a conductive film obtained by processing the same conductive film as the conductive layer 129. The conductive layer 166 is exposed on the top surface of the connection portion 204. Therefore, the connection portion 204 can be electrically connected to the FPC 172 through the connection layer 242.

[0365] Preferably, the light-shielding layer 117 is provided on the surface of the substrate 152 on the substrate 151 side. Alternatively, color layers 132R and 132G may be provided on the surface of the substrate 152 on the substrate 151 side. In FIG13A, when viewed with reference to the substrate 152, the color layers 132R and 132G cover a portion of the light-shielding layer 117.

[0366] The substrates 151 and 152 may be made of the material that can be used on the substrate 120 as shown in Embodiment 1. In addition, the outer side of the substrates 151 or 152 may also be made of various components that can be disposed on the outer side of the substrate 120.

[0367] As the adhesive layer 142, the material that can be used for the resin layer 122 as shown in Embodiment 1 can be used.

[0368] As the connecting layer 242, anisotropic conductive film (ACF) or anisotropic conductive paste (ACP) can be used.

[0369] Materials that can be used as gates, sources, and drains of transistors, as well as conductive layers such as wiring and electrodes constituting display devices, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or alloys with the above metals as the main component. Films containing these materials can be used in single-layer or multi-layer structures.

[0370] In addition, as a transparent conductive material, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and gallium-containing zinc oxide, or graphene, can be used. Alternatively, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or alloys containing such metallic materials, can be used. Alternatively, nitrides of the metallic materials (e.g., titanium nitride) can also be used. Furthermore, when using metallic or alloy materials (or their nitrides), it is preferable to form them thin enough to be transparent. Furthermore, a laminate of the above materials can be used as a conductive layer. For example, using a laminate of an alloy of silver and magnesium with indium tin oxide is preferable because it can improve conductivity. The above materials can also be used to construct various conductive layers such as wiring and electrodes in a display device, as well as conductive layers included in light-emitting devices (conductive layers used as pixel electrodes or common electrodes).

[0371] As insulating materials that can be used in various insulating layers, examples include resins such as acrylic resin or epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, or aluminum oxide.

[0372] [Display Device 100B] The main difference between the display device 100B shown in Figure 14 and the display device 100A is that it adopts a bottom-emitting structure. Note that the description of parts that are the same as those in the display device 100A is sometimes omitted.

[0373] Light emitted from the light-emitting device is emitted to one side of the substrate 151. The substrate 151 is preferably made of a material with high transmittance to visible light. On the other hand, there is no limitation on the transmittance of the material used for the substrate 152.

[0374] In addition, in the display device 100B, the conductive layer 126 and the conductive layer 129 include materials that transmit visible light and the common electrode 115 includes materials that reflect visible light.

[0375] Preferably, a light-shielding layer 117 is formed between the substrate 151 and the transistor 201 and between the substrate 151 and the transistor 205. In the example shown in FIG14, 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.

[0376] Furthermore, in the display device 100B, a color layer 132R that transmits red light and a color layer 132G that transmits green light are disposed between the insulating layer 215 and the insulating layer 214. Preferably, the ends of the color layer 132R and the ends of the color layer 132G overlap with the light-shielding layer 117. The light emitted by the light-emitting device 130 overlapping with the color layer 132R is extracted as red light through the color layer 132R and is emitted as green light to the outside of the display device 100B. Note that, although not shown, a color layer 132B that transmits blue light is also disposed between the insulating layer 215 and the insulating layer 214, and the light emitted by the light-emitting device 130 overlapping with the color layer 132B is extracted as blue light to the outside of the display device 100B through the color layer 132B.

[0377] Here, Figures 15A to 15D show the cross-sectional structure of display devices 100A and 100B, including conductive layers 126 and 128 and the surrounding region 138.

[0378] Figures 13A and 14 show examples where the top surface of layer 128 is substantially aligned with the top surface of conductive layer 126, but the present invention is not limited thereto. For example, as shown in Figure 15A, sometimes the top surface of layer 128 is higher than the top surface of conductive layer 126. In this case, the top surface of layer 128 has a convex shape that expands gently towards the center.

[0379] Additionally, as shown in FIG15B, sometimes the top surface of layer 128 is lower than the top surface of conductive layer 126. In this case, the top surface of layer 128 has a concave shape that gently slopes towards the center.

[0380] Additionally, as shown in FIG15C, when the top surface of layer 128 is higher than the top surface of conductive layer 126, sometimes the width of the upper part of layer 128 is greater than the width of the recess in conductive layer 126. In this case, sometimes a part of layer 128 covers a portion of the generally flat area of ​​conductive layer 126.

[0381] Additionally, as shown in FIG15D, sometimes in the structure shown in FIG15C, layer 128 also has a recess on its top surface. This recess has a shape that is gently recessed towards the center.

[0382] This embodiment can be appropriately combined with other embodiments.

[0383] Embodiment 3 In this embodiment, a display device according to an embodiment of the present invention will be described with reference to FIGS. 16 to 21.

[0384] The display device of this embodiment can be a high-definition display device. Therefore, for example, the display device of this embodiment can be used as the display unit of information terminal devices (wearable devices) such as watch-type and bracelet-type devices, as well as the display unit of wearable devices that can be worn on the head, such as VR devices such as head-mounted displays and AR devices such as glasses-type devices.

[0385] In the display device of this embodiment, the light-emitting devices adopt a series structure, so the chromaticity change between low-brightness and high-brightness light emission is small. Furthermore, in the display device of this embodiment, the EL layer in each light-emitting device is separated, so even in a high-definition display device, crosstalk between adjacent sub-pixels can be suppressed. Therefore, a high-definition display device with high display quality can be realized.

[0386] Specifically, the resolution of the display portion of the display device according to one embodiment of the present invention is preferably 1000ppi or more, 2000ppi or more, 3000ppi or more, 5000ppi or more, or 6000ppi or more and 20000ppi or less or 30000ppi or less.

[0387] [Display Module] FIG16A is a perspective view of display module 280. Display module 280 includes display device 100C and FPC 290. Note that the display device included in display module 280 is not limited to display device 100C, but may be any of display devices 100D to 100G, which will be described later.

[0388] The display module 280 includes a substrate 291 and a substrate 292. The display module 280 includes a display section 281. The display section 281 is an image display area in the display module 280, and can display light from each pixel disposed in the pixel section 284 described below.

[0389] FIG16B is a perspective view of the structure of one side of 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 on the substrate 291. In addition, a terminal section 285 for connecting to the FPC 290 is provided on 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 through a wiring section 286 composed of multiple wirings.

[0390] The pixel unit 284 includes a plurality of pixels 284a arranged periodically. An enlarged view of a pixel 284a is shown on the right side of FIG16B. A pixel 110R emitting red light, a sub-pixel 110G emitting green light, and a sub-pixel 110B emitting blue light are sequentially arranged in the pixel 284a. Regarding the pixel layout applicable to the pixel unit 284, please refer to Embodiment 1.

[0391] The pixel circuit section 283 includes a plurality of pixel circuits 283a arranged periodically.

[0392] A pixel circuit 283a controls the light emission of the three light-emitting devices included in a pixel 284a. A pixel circuit 283a can be composed of three circuits that control the light emission of a single light-emitting device. For example, the pixel circuit 283a can be structured to have at least one select transistor, one current control transistor (driving transistor), and a capacitor for each light-emitting device. In this case, the gate of the select transistor is input with a gate signal, and the source is input with a source signal. Thus, an active matrix display device is realized.

[0393] The circuit section 282 includes circuitry for driving each pixel circuit 283a of the pixel circuit section 283. For example, it is preferably one or both of a gate line driving circuit and a source line driving circuit. In addition, it may also include at least one of an arithmetic circuit, a memory circuit, and a power supply circuit.

[0394] The FPC290 is used for wiring to supply video signals or power potentials, etc., from the outside to the circuit section 282. In addition, ICs can also be mounted on the FPC290.

[0395] The display module 280 can adopt a structure in which one or both of the pixel circuit section 283 and the circuit section 282 are stacked on the lower side of the pixel section 284, so that the display section 281 can have an extremely high aperture ratio (effective display area ratio). For example, the aperture ratio of the display section 281 can be 40% or more and less than 100%, preferably 50% or more and less than 95%, and more preferably 60% or more and less than 95%. In addition, the pixels 284a can be arranged in an extremely high density, thereby enabling the display section 281 to have extremely high resolution. For example, the display section 281 is preferably arranged with a resolution of 20,000 ppi or less, or 30,000 ppi or less and 2,000 ppi or more, more preferably 3,000 ppi or more, further preferably 5,000 ppi or more, and even more preferably 6,000 ppi or more.

[0396] This high-definition display module 280 is suitable for use in VR devices such as head-mounted displays or AR devices such as glasses. For example, because the display module 280 has an extremely high-definition display section 281, even when the display section of the display module 280 is viewed through a lens, the user cannot see the pixels, thereby achieving a highly immersive display. Furthermore, not limited to this, the display module 280 can also be applied to electronic devices with relatively small display sections. For example, it is suitable for use in the display section of wearable electronic devices such as watch-type devices.

[0397] [Display Device 100C] The display device 100C shown in FIG. 17A includes a substrate 301, a light-emitting device 130, a color layer 132R, a color layer 132G, a color layer 132B, a capacitor 240, and a transistor 310, etc. Sub-pixel 110R includes a light-emitting device 130 and a color layer 132R, sub-pixel 110G includes a light-emitting device 130 and a color layer 132G, and sub-pixel 110B includes a light-emitting device 130 and a color layer 132B. The light-emitting device 130 can emit white light. In sub-pixel 110R, the light emitted by the light-emitting device 130 is extracted as red light through the color layer 132R and transmitted to the outside of the display device 100C. Similarly, in sub-pixel 110G, the light emitted by the light-emitting device 130 is extracted as green light through the color layer 132G and transmitted to the outside of the display device 100C. In sub-pixel 110B, the light emitted by the light-emitting device 130 is extracted as blue light through the color layer 132B and sent to the outside of the display device 100C.

[0398] The light-emitting devices included in each sub-pixel that emits light of each color all adopt the same structure, for example, they can all adopt a structure that emits white light. Specifically, the EL layer 113 included in each light-emitting device can have the same structure. On the other hand, since the EL layer 113 included in each light-emitting device is separated, leakage current between the light-emitting devices can be suppressed. As a result, the display quality of the display device can be improved.

[0399] The substrate 301 corresponds to the substrate 291 in FIG16A and FIG16B. The stacked structure from the substrate 301 to the insulating layer 255b corresponds to the layer 101 with transistor in Embodiment 1.

[0400] Transistor 310 is a transistor having a channel forming region in substrate 301. Substrate 301 can be, for example, a semiconductor substrate such as a single-crystal silicon substrate. Transistor 310 includes a portion of substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. Conductive layer 311 serves as a gate electrode. Insulating layer 313 is located between substrate 301 and conductive layer 311 and serves as a gate insulating layer. Low-resistance region 312 is a region in substrate 301 doped with impurities and serves as one of the source and drain electrodes. Insulating layer 314 is provided to cover the sides of conductive layer 311.

[0401] Furthermore, a component separation layer 315 is provided between two adjacent transistors 310 in such a way as to be embedded in the substrate 301.

[0402] In addition, an insulating layer 261 is provided in such a way as to cover the transistor 310, and a capacitor 240 is provided on the insulating layer 261.

[0403] The capacitor 240 includes a conductive layer 241, a conductive layer 245, and an insulating layer 243 located therebetween. The conductive layer 241 serves as one electrode in the capacitor 240, the conductive layer 245 serves as the other electrode in the capacitor 240, and the insulating layer 243 serves as the dielectric of the capacitor 240.

[0404] A conductive layer 241 is disposed on an insulating layer 261 and embedded in an insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain electrodes of a transistor 310 through a plug 271 embedded in the insulating layer 261. An insulating layer 243 is disposed covering the conductive layer 241. A conductive layer 245 is disposed in the region where it overlaps with the conductive layer 241, separated by the insulating layer 243.

[0405] An insulating layer 255a is provided in such a way as to cover the capacitor 240, and an insulating layer 255b is provided on the insulating layer 255a.

[0406] For each of the insulating layers 255a and 255b, various inorganic insulating films such as oxide insulating films, nitride insulating films, oxynitride insulating films, and oxynitride insulating films can be suitably used. As the insulating layer 255a, it is preferable to use an oxide insulating film or an oxynitride insulating film such as a silicon oxide film, an oxynitride silicon film, or an aluminum oxide film. As the insulating layer 255b, it is preferable to use a nitride insulating film or an oxynitride insulating film such as a silicon nitride film or an oxynitride silicon film. More specifically, it is preferable to use a silicon oxide film as the insulating layer 255a and a silicon nitride film as the insulating layer 255b. The insulating layer 255b is preferably used as an etching protective film. Alternatively, an oxynitride insulating film or an oxynitride insulating film can be used as the insulating layer 255a and an oxide insulating film or an oxynitride insulating film can be used as the insulating layer 255b. This embodiment shows an example where the insulating layer 255b has a recess, but the insulating layer 255b may also not have a recess.

[0407] A light-emitting device 130 is disposed on the insulating layer 255b. This embodiment shows an example in which the light-emitting device 130 has the same structure as the stacked structure shown in FIG. 1B. The side surface of the pixel electrode 111 and the side surface of the EL layer 113 are each covered by the insulating layer 125 and overlap with the insulating layer 127 through the insulating layer 125. A common layer 114 is disposed on the EL layer 113, the insulating layer 125 and the insulating layer 127, and a common electrode 115 is disposed on the common layer 114.

[0408] The pixel electrode 111 of the light-emitting device is electrically connected to one of the source and drain electrodes of the transistor 310 through a plug 256 embedded in insulating layers 255a and 255b, a conductive layer 241 embedded in insulating layer 254, and a plug 271 embedded in insulating layer 261. The height of the top surface of insulating layer 255b is the same as or approximately the same as the height of the top surface of plug 256. Various conductive materials can be used as plugs.

[0409] In addition, a protective layer 131 is provided on the light-emitting device 130. Color layers 132R, 132G, and 132B are provided on the protective layer 131. The substrate 120 is bonded to the color layers 132R, 132G, and 132B by a resin layer 122. For details of the assembly of the light-emitting device to the substrate 120, please refer to Embodiment 1. The substrate 120 corresponds to the substrate 292 in FIG16A.

[0410] The top surfaces of the pixel electrodes 111 are not covered by an insulating layer. Therefore, the spacing between adjacent light-emitting devices can be made extremely small. Thus, a high-definition or high-resolution display device can be realized.

[0411] As shown in Figures 17B and 17C, a lens array 133 can also be provided. By using the lens array 133, the light emitted by the light-emitting device 130 can be concentrated.

[0412] In the example shown in FIG17B, color layers 132R, 132G, and 132B are disposed on the light-emitting device 130 with a protective layer 131 in between, an insulating layer 134 is disposed on the color layers 132R, 132G, and 132B, and a lens array 133 is disposed on the insulating layer 134. By directly forming the color layers 132R, 132G, 132B, and lens array 133 on the substrate on which the light-emitting device 130 is formed, the accuracy of the positional alignment between the light-emitting device and the color layers or lens array can be improved.

[0413] One or both of inorganic and organic insulating films can be used as the insulating layer 134. The insulating layer 134 can have a single-layer structure or a multilayer structure. As the insulating layer 134, for example, a material that can also be used for the protective layer 131 can be used. Since the light emitted by the light-emitting device is extracted through the insulating layer 134, the insulating layer 134 preferably has high transmittance to visible light.

[0414] In Figure 17B, the light emitted by the light-emitting device 130 is extracted to the outside of the display device after passing through the color layer and the lens array 133. By positioning the light-emitting device and the color layer, color mixing can be suppressed and viewing angle characteristics can be improved, which is preferable. Alternatively, the lens array 133 can be provided on the light-emitting device 130 and the color layer can be provided on the lens array 133.

[0415] Figure 17C shows an example where a substrate 120 having color layers 132R, 132G, 132B, and a lens array 133 is bonded to a protective layer 131 by a resin layer 122. By providing color layers 132R, 132G, 132B, and the lens array 133 on the substrate 120, the heat treatment temperature during their formation process can be increased.

[0416] In the example shown in FIG17C, color layers 132R, 132G, and 132B are provided in contact with substrate 120, insulating layer 134 is provided in contact with color layers 132R, 132G, and 132B, and lens array 133 is provided in contact with insulating layer 134.

[0417] In FIG. 17C, the light emitted by the light-emitting device 130 is extracted to the outside of the display device after passing through the lens array 133 and the color layer. Alternatively, the lens array 133 may be disposed in contact with the substrate 120, the insulating layer 134 may be disposed in contact with the lens array 133, and the color layer may be disposed in contact with the insulating layer 134. In this case, the light emitted by the light-emitting device 130 is extracted to the outside of the display device after passing through the color layer and the lens array 133.

[0418] The convex surface of the lens array 133 can face both the substrate 120 side and the light-emitting device 130 side.

[0419] The lens array 133 can be formed from at least one of inorganic and organic materials. For example, the lens can be made of a material containing resin. Furthermore, a material containing at least one of oxides and sulfides can be used for the lens. As the lens array 133, a microlens array can be used, for example. The lens array 133 can be formed directly on a substrate or on a light-emitting device, or it can be bonded to a separately formed lens array.

[0420] [Display Device 100D] The main difference between the display device 100D shown in FIG18 and the display device 100C lies in the structure of the transistor. In addition, in the description of the display device described below, the same parts as those described previously are sometimes omitted.

[0421] Transistor 320 is a transistor (OS transistor) that uses metal oxide (also known as oxide semiconductor) in the semiconductor layer that forms the channel.

[0422] The transistor 320 includes a semiconductor layer 321, an insulating layer 323, a conductive layer 324, a pair of conductive layers 325, an insulating layer 326, and a conductive layer 327.

[0423] The substrate 331 corresponds to the substrate 291 in Figures 16A and 16B. The stacked structure from the substrate 331 to the insulating layer 255b corresponds to the layer 101 with a transistor in Embodiment 1. An insulating substrate or a semiconductor substrate can be used as the substrate 331.

[0424] An insulating layer 332 is provided on the substrate 331. The insulating layer 332 serves as a barrier layer, which prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320 and prevents oxygen from escaping from the semiconductor layer 321 to the insulating layer 332 side. As the insulating layer 332, for example, a film that is less susceptible to hydrogen or oxygen diffusion than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film, can be used.

[0425] A conductive layer 327 is provided on the insulating layer 332, and an insulating layer 326 is provided to cover the conductive layer 327. The conductive layer 327 serves as the first gate electrode of the transistor 320, and a portion of the insulating layer 326 serves as the first gate insulating layer. Preferably, the portion of the insulating layer 326 that contacts the semiconductor layer 321 is an oxide insulating film such as a silicon oxide film. Preferably, the top surface of the insulating layer 326 is planarized.

[0426] A semiconductor layer 321 is disposed on an insulating layer 326. Preferably, the semiconductor layer 321 contains a metal oxide (also known as an oxide semiconductor) film with semiconductor properties.

[0427] A pair of conductive layers 325 are in contact with the semiconductor layer 321 and serve as the source electrode and the drain electrode.

[0428] In addition, an insulating layer 328 is provided to cover the top and side surfaces of the pair of conductive layers 325 and the side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided on the insulating layer 328. The insulating layer 328 serves as a barrier layer, which prevents impurities such as water or hydrogen from diffusing from the insulating layer 264 to the semiconductor layer 321 and oxygen from detaching from the semiconductor layer 321. As the insulating layer 328, the same insulating film as the insulating layer 332 described above can be used.

[0429] Openings are provided in insulating layer 328 and insulating layer 264 to reach semiconductor layer 321. An insulating layer 323 and a conductive layer 324 are embedded inside the openings, contacting the sides of insulating layer 264, insulating layer 328, and conductive layer 325, as well as the top surface of semiconductor layer 321. Conductive layer 324 is used as a second gate electrode, and insulating layer 323 is used as a second gate insulating layer.

[0430] The top surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are flattened so that their heights are all the same or approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0431] Insulating layers 264 and 265 are used as interlayer insulating layers. Insulating layer 329 is used as a barrier layer to prevent impurities such as water or hydrogen from diffusing from insulating layer 265 to transistor 320. Insulating layer 329 may use the same insulating film as insulating layers 328 and 332 described above.

[0432] A plug 274, electrically connected to one of the pair of conductive layers 325, is embedded in insulating layers 265, 329, and 264. Preferably, the plug 274 is a conductive layer 274a having a portion of the side surface covering the openings of each of the insulating layers 265, 329, 264, and 328, and a conductive layer 274b in contact with the top surface of the conductive layer 274a. Preferably, the conductive layer 274a is made of a conductive material that does not readily diffuse hydrogen and oxygen.

[0433] The structure of the insulating layer 254 to the substrate 120 in the display device 100D is the same as that in the display device 100C.

[0434] [Display Device 100E] In the display device 100E shown in FIG19, a transistor 310 with a channel formed in a substrate 301 and a transistor 320 with a metal oxide semiconductor layer forming the channel are stacked.

[0435] An insulating layer 261 is provided to cover the transistor 310, and a conductive layer 251 is provided on the insulating layer 261. Furthermore, an insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided on the insulating layer 262. Both conductive layers 251 and 252 are used for wiring. Furthermore, insulating layers 263 and 332 are provided to cover the conductive layer 252, and a transistor 320 is provided on the insulating layer 332. Furthermore, an insulating layer 265 is provided to cover the transistor 320, and a capacitor 240 is provided on the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected through a connector 274.

[0436] Transistor 320 can be used as a transistor constituting a pixel circuit. Furthermore, transistor 310 can 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) used to drive the pixel circuit. Moreover, transistors 310 and 320 can be used as transistors constituting various circuits such as arithmetic circuits or memory circuits.

[0437] With this structure, not only pixel circuits but also driving circuits can be formed directly under the light-emitting device. Therefore, compared with the case where driving circuits are set around the display area, the display device can be miniaturized.

[0438] [Display Device 100F] The display device 100F shown in FIG20 has a stacked structure of transistors 310A and 310B, each having a channel formed on a semiconductor substrate.

[0439] The display device 100F has a structure in which a substrate 301B, on which a transistor 310B, a capacitor 240 and a light-emitting device are disposed, and a substrate 301A on which a transistor 310A is disposed are bonded together.

[0440] Preferably, an insulating layer 345 is provided on the bottom surface of the substrate 301B. Alternatively, preferably, an insulating layer 346 is provided on the insulating layer 261 provided on the substrate 301A. The insulating layers 345 and 346 are insulating layers used as protective layers, which can suppress the diffusion of impurities into the substrates 301B and 301A. Inorganic insulating films suitable for use in the protective layer 131 can be used as the insulating layers 345 and 346.

[0441] The substrate 301B is provided with a plug 343 that penetrates the substrate 301B and the insulating layer 345. Preferably, the insulating layer 344 is provided in such a way that it covers the side of the plug 343. The insulating layer 344 is an insulating layer used as a protective layer to suppress the diffusion of impurities into the substrate 301B. As the insulating layer 344, an inorganic insulating film suitable for the protective layer 131 can be used.

[0442] Furthermore, a conductive layer 342 is provided below the insulating layer 345 on the back side (the surface opposite to the substrate 120 side) of the substrate 301B. Preferably, the conductive layer 342 is provided in a manner that embeds it within the insulating layer 335. Additionally, the bottom surfaces of the conductive layer 342 and the insulating layer 335 are preferably planarized. Here, the conductive layer 342 is electrically connected to the plug 343.

[0443] On the other hand, a conductive layer 341 is provided on the insulating layer 346 of the substrate 301A. The conductive layer 341 is preferably provided in a manner that fills the insulating layer 336. In addition, the bottom surfaces of the conductive layer 341 and the insulating layer 336 are preferably planarized.

[0444] When conductive layer 341 and conductive layer 342 are bonded together, substrate 301A and substrate 301B are electrically connected. Here, by improving the flatness of the surface formed by conductive layer 342 and insulating layer 335 and the surface formed by conductive layer 341 and insulating layer 336, conductive layer 341 and conductive layer 342 can be bonded well.

[0445] It is preferable to use the same conductive material for both conductive layers 341 and 342. For example, a metal film containing elements 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 aforementioned elements can be used. In particular, copper is preferably used for both conductive layers 341 and 342. This allows for the use of Cu-Cu (copper-copper) direct bonding technology (a technology that connects Cu (copper) pads to each other to achieve electrical conductivity).

[0446] [Display Device 100G] FIG20 shows an example of using Cu-Cu direct bonding technology when bonding conductive layer 341 and conductive layer 342, but the present invention is not limited thereto. As shown in FIG21, the structure in display device 100G can also be formed by bonding conductive layer 341 and conductive layer 342 by bump 347.

[0447] As shown in FIG21, by providing a bump 347 between conductive layer 341 and conductive layer 342, conductive layer 341 and conductive layer 342 can be electrically connected. The bump 347 can be formed using conductive materials such as gold (Au), nickel (Ni), indium (In), and tin (Sn). In addition, solder is sometimes used as the bump 347. In addition, an adhesive layer 348 can be provided between insulating layer 345 and insulating layer 346. In addition, insulating layer 335 and insulating layer 336 may not be provided when providing bump 347.

[0448] [Display Device 100H] FIG22 is a cross-sectional view of display device 100H. Display device 100H has transistors 310, 320a, 320b, capacitor 240, light-emitting device 130, color layer 132R, color layer 132G, and connecting portion 140 disposed between substrate 301 and substrate 120. Light-emitting device 130 and connecting portion 140 are disposed on insulating layer 255. Materials suitable for insulating layers 255a and 255b can be used as insulating layer 255. Insulating layer 255 may have a stacked structure of insulating layers 255a and 255b. Insulating layer 255 and substrate 120 are bonded together by sealant 361. Materials suitable for adhesive layer 142 can be used as sealant 361.

[0449] The light-emitting device 130 included in the display device 100H can emit white light. Furthermore, by providing a color layer with an area overlapping the light-emitting device 130, the display device 100H can perform full-color display. Figure 22 shows a color layer 132R that transmits red light and a color layer 132G that transmits green light, which are provided in the color layer of the display device 100H. Figure 22 also shows the light-emitting device 130 overlapping with the color layer 132R and the light-emitting device 130 overlapping with the color layer 132G. In Figure 22, the area where the color layers 132R and 132G overlap is shown in dashed lines.

[0450] The pixel electrode 111 of the light-emitting device 130 is electrically connected to one of the source and drain electrodes of the transistor 320b and the conductive layer 245 of the capacitor 240. The conductive layer 241 of the capacitor 240 is electrically connected to one of the source and drain electrodes of the transistor 320a. The other of the source and drain electrodes of the transistor 320a is electrically connected to one of the source and drain electrodes of the transistor 310.

[0451] Transistors 320a and 320b may have the same structure as transistor 320. In other words, transistor 320 may be, for example, an OS transistor.

[0452] The conductive layer 123 included in the connecting portion 140 is electrically connected to the conductive layer 351a on the insulating layer 255 through the wiring 355a on the insulating layer 354. The conductive layer 351a is electrically connected to the FPC 172a through the connecting layer 242a. As described above, the common electrode 115 is electrically connected to the conductive layer 123, so the common electrode 115 is electrically connected to the FPC 172a through the conductive layer 123, the wiring 355a, the conductive layer 351a, and the connecting layer 242a. Thus, the common electrode 115 is supplied with a potential such as a power supply potential from outside the display device 100H through the FPC 172a.

[0453] The end of the conductive layer 351a is covered by the sacrificial layer 353a. In addition, the insulating layer 125a and the insulating layer 127a are sequentially stacked on the sacrificial layer 353a.

[0454] The other of the source and drain electrodes of transistor 320b is electrically connected to the conductive layer 351b on insulating layer 255 through wiring 355b and the like provided on insulating layer 354. Conductive layer 351b is electrically connected to FPC172b through connection layer 242b. Thus, the other of the source and drain electrodes of transistor 320b is electrically connected to FPC172b through wiring 355b, conductive layer 351b, and connection layer 242b. As a result, the other of the source and drain electrodes of transistor 320b is supplied with a potential such as a power supply potential from outside the display device 100H through FPC172b and the like.

[0455] Here, the potential supplied to FPC172a and the potential supplied to FPC172b can be different from each other. For example, a high potential can be supplied to FPC172a and a low potential can be supplied to FPC172b. Alternatively, a low potential can be supplied to FPC172a and a high potential can be supplied to FPC172b. In this way, current can flow through the light-emitting device 130 to make the light-emitting device 130 emit light.

[0456] The end of the conductive layer 351b is covered by the sacrificial layer 353b. In addition, the insulating layer 125b and the insulating layer 127b are sequentially stacked on the sacrificial layer 353b.

[0457] Connecting layers 242a and 242b may have the same structure as connecting layer 242, for example, ACF may be used. Additionally, sacrificial layers 353a and 353b may each have a stacked structure of sacrificial layers 118 and 119 (see Figure 6C). Furthermore, insulating layers 125a and 125b comprise the same material as insulating layer 125, and insulating layers 127a and 127b comprise the same material as insulating layer 127.

[0458] The conductive layers 351a and 351b can be formed using the same materials and the same process as the pixel electrode 111 and the conductive layer 123.

[0459] A connecting portion 140 is disposed between the display portion on which the light-emitting device 130 is disposed and the sealant 361. On the other hand, conductive layer 351a, connecting layer 242a, FPC 172a, sacrificial layer 353a, insulating layer 125a, and insulating layer 127a are disposed on the outside of the sealant 361 (opposite to the display portion). In addition, conductive layer 351b, connecting layer 242b, FPC 172b, sacrificial layer 353b, insulating layer 125b, and insulating layer 127b are disposed on the outside of the sealant 361 (opposite to the display portion). Conductive layer 351a, conductive layer 351b, connecting layer 242a, connecting layer 242b, FPC 172a, FPC 172b, sacrificial layer 353a, sacrificial layer 353b, insulating layer 125a, insulating layer 125b, insulating layer 127a, and insulating layer 127b have areas that do not overlap with the substrate 120.

[0460] This embodiment can be appropriately combined with other embodiments.

[0461] Embodiment 4 In this embodiment, a light-emitting device of a display device that can be used in one embodiment of the present invention will be described.

[0462] As shown in FIG23A, the light-emitting device includes an EL layer 786 between a pair of electrodes (lower electrode 772 and upper electrode 788). The EL layer 786 may be composed of multiple layers such as layer 4420, light-emitting layer 4411, and layer 4430. Layer 4420 may include, for example, a layer containing a substance with high electron injection capability (electron injection layer) and a layer containing a substance with high electron transport capability (electron transport layer). Light-emitting layer 4411 may, for example, contain a luminescent compound. Layer 4430 may, for example, include a layer containing a substance with high hole injection capability (hole injection layer) and a layer containing a substance with high hole transport capability (hole transport layer).

[0463] The structure including layer 4420, light-emitting layer 4411 and layer 4430 disposed between a pair of electrodes can be used as a single light-emitting unit. In this specification, the structure of FIG23A is referred to as a single structure.

[0464] Additionally, FIG23B shows a modified example of the EL layer 786 included in the light-emitting device shown in FIG23A. Specifically, the light-emitting device shown in FIG23B includes layer 4431 on the lower electrode 772, layer 4432 on layer 4431, light-emitting layer 4411 on layer 4432, layer 4421 on light-emitting layer 4411, layer 4422 on layer 4421, and upper electrode 788 on layer 4422. For example, when the lower electrode 772 is used as an anode and the upper electrode 788 is used as a cathode, layer 4431 is used as a hole injection layer, layer 4432 is used as a hole transport layer, layer 4421 is used as an electron transport layer, and layer 4422 is used as an electron injection layer. Alternatively, when the lower electrode 772 is used as the cathode and the upper electrode 788 is used as the anode, layer 4431 is used as an electron injection layer, layer 4432 as an electron transport layer, layer 4421 as a hole transport layer, and layer 4422 as a hole injection layer. By employing the above layer structure, carriers can be efficiently injected into the light-emitting layer 4411, thereby improving the recombination efficiency of carriers within the light-emitting layer 4411.

[0465] In addition, as shown in Figures 23C and 23D, the structure in which multiple light-emitting layers (light-emitting layer 4411, light-emitting layer 4412, and light-emitting layer 4413) are disposed between layer 4420 and layer 4430 is also a variation of the single structure.

[0466] Furthermore, as shown in Figures 23E and 23F, the structure in this specification where multiple light-emitting units (EL layers 786a and 786b) are connected in series with the charge-generating layer 4440 in between is called a series structure. Alternatively, the series structure can also be called a stacked structure. By employing a series structure, a light-emitting device capable of emitting light with high brightness can be realized.

[0467] In Figures 23C and 23D, light-emitting materials that emit light of the same color, or even the same light-emitting material, can be used for light-emitting layers 4411, 4412, and 4413. For example, a light-emitting material that emits blue light can be used for light-emitting layers 4411, 4412, and 4413. A color conversion layer can also be provided as layer 785 shown in Figure 23D.

[0468] Alternatively, luminescent materials that emit light of different colors can be used in luminescent layers 4411, 4412, and 4413. When the light emitted by each of luminescent layer 4411, 4412, and 4413 is in a complementary color relationship, white light emission can be obtained. As layer 785 shown in FIG. 23D, a color filter (also called a color layer) can also be provided. When white light passes through the color filter, light of the desired color can be obtained.

[0469] Additionally, in Figures 23E and 23F, luminescent materials emitting the same color of light, or even the same luminescent material, can be used for luminescent layers 4411 and 4412. Alternatively, luminescent materials emitting different colors of light can be used for luminescent layers 4411 and 4412. When the light emitted by luminescent layer 4411 and the light emitted by luminescent layer 4412 are complementary colors, white light emission can be obtained. Figure 23F shows an example where layer 785 is also provided. Layer 785 can be one or both of a color conversion layer and a color filter (color layer).

[0470] Note that in Figures 23C, 23D, 23E and 23F, as shown in Figure 23B, layers 4420 and 4430 may also have a stacked structure consisting of two or more layers.

[0471] A structure in which each light-emitting device emits a light color (e.g., blue (B), green (G) and red (R)) is formed separately is called an SBS (Side By Side) structure.

[0472] The emission color of the light-emitting device can be red, green, blue, cyan, magenta, yellow, or white, depending on the material constituting the EL layer 786. Furthermore, when the light-emitting device has a microcavity structure, the color purity can be further improved.

[0473] Preferably, the white light-emitting device has a structure in which the light-emitting layer contains two or more light-emitting materials. To obtain white light emission, it is possible to select light-emitting materials in which the light emission of the two light-emitting materials is in a complementary color relationship, or to obtain a white light-emitting material by combining the light emission of two or more light-emitting materials. For example, when obtaining white light emission using two light-emitting layers, by making the light emission colors of the two light-emitting layers in a complementary color relationship, a light-emitting device that emits white light throughout the entire device can be obtained. Furthermore, when obtaining white light emission using three or more light-emitting layers, a structure in which the light emission colors of the three or more light-emitting layers are combined to obtain a structure that emits white light throughout the entire device can be obtained.

[0474] Preferably, the luminescent layer comprises two or more luminescent materials, each emitting light in the form of R (red), G (green), B (blue), Y (yellow), O (orange), etc. Alternatively, it preferably comprises two or more luminescent materials, each emitting light in the form of two or more spectral components of R, G, and B.

[0475] This embodiment can be appropriately combined with other embodiments.

[0476] Embodiment 5 In this embodiment, an electronic device according to an embodiment of the present invention will be described using Figures 24 to 27.

[0477] The electronic device of this embodiment includes a display device according to one embodiment of the present invention in its display section. The display device according to one embodiment of the present invention can easily achieve high definition and high resolution. Therefore, it can be used in the display section of various electronic devices.

[0478] As electronic devices, in addition to electronic devices with large screens such as televisions, desktop or laptop personal computers, monitors for computers, digital signage, and large game consoles such as pinball machines, examples include digital cameras, digital camcorders, digital photo frames, mobile phones, portable game consoles, portable information terminals, and audio playback devices.

[0479] In particular, since the display device of one embodiment of the present invention can improve clarity, it can be suitably used in electronic devices that include a small display section. Examples of such electronic devices include watch-type and bracelet-type information terminal devices (wearable devices), wearable devices that can be worn on the head, VR devices such as head-mounted displays, AR devices such as glasses, and MR devices.

[0480] A display device according to one embodiment of the present invention preferably has extremely high resolution, such as HD (1280×720 pixels), FHD (1920×1080 pixels), WQHD (2560×1440 pixels), WQXGA (2560×1600 pixels), 4K (3840×2160 pixels), 8K (7680×4320 pixels), etc. In particular, it is preferred to set the resolution to 4K, 8K or higher. In addition, the pixel density (clarity) in the display device according to one embodiment of the present invention is preferably 100ppi or higher, preferably 300ppi or higher, more preferably 500ppi or higher, further preferably 1000ppi or higher, even more preferably 2000ppi or higher, even more preferably 3000ppi or higher, still more preferably 5000ppi or higher, and even more preferably 7000ppi or higher. By using a display device with one or both of the aforementioned high resolution and high definition, realism and depth can be further enhanced in personal electronic devices such as portable or home-use devices. Furthermore, there is no particular limitation on the screen aspect ratio (vertical-to-horizontal ratio) of the display device according to one embodiment of the present invention. For example, the display device can accommodate various screen aspect ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0481] The electronic device of this embodiment may also include a sensor (which has the function of measuring factors such as force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, tilt, vibration, odor, or infrared radiation).

[0482] The electronic device of this embodiment may have various functions. For example, it may have the following functions: displaying various information (still images, moving images, text images, etc.) on the display unit; touch panel function; displaying calendar, date or time, etc.; executing various software (programs); performing wireless communication function; reading programs or data stored in the storage medium; etc.

[0483] An example of a wearable device that can be worn on the head is illustrated using Figures 24A to 24D. These wearable devices have one or both of the functions of displaying AR content and displaying VR content. In addition, these wearable devices may also have the function of displaying SR or MR content in addition to AR and VR. When an electronic device has the function of displaying AR, VR, SR, MR, etc., the user's immersion can be enhanced.

[0484] The electronic device 700A shown in FIG24A and the electronic device 700B shown in FIG24B both include a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical components 753, a frame 757 and a pair of nose pads 758.

[0485] The display panel 751 can be applied to a display device according to one embodiment of the present invention. Therefore, an electronic device capable of displaying with extremely high clarity can be realized.

[0486] Both electronic devices 700A and 700B can project the image displayed by the display panel 751 onto the display area 756 in the optical component 753. Because the optical component 753 is light-transmitting, the user can see the image displayed in the display area by superimposing it with the image seen through the optical component 753. Therefore, both electronic devices 700A and 700B are electronic devices capable of AR display.

[0487] A camera capable of capturing images in front can also be provided as an imaging unit on electronic devices 700A and 700B. In addition, by providing an accelerometer such as a gyroscope sensor on electronic devices 700A and 700B, the orientation of the user's head can be detected and the image corresponding to that orientation can be displayed on the display area 756.

[0488] The communications department has a wireless communication device, through which image signals can be supplied. In addition, a connector capable of connecting a cable that supplies image signals and power potential may be included instead of the wireless communication device or in addition to the wireless communication device.

[0489] In addition, electronic devices 700A and 700B are equipped with batteries that can be charged wirelessly or wiredly or both.

[0490] A touch sensor module may also be provided on the housing 721. The touch sensor module has the function of detecting whether the outer surface of the housing 721 is touched. By means of the touch sensor module, various processes can be performed by detecting user tapping or swiping operations. For example, by means of tapping operations, processes such as temporarily pausing or replaying moving images can be performed, and by means of swiping operations, processes such as fast forwarding and rewinding can be performed. In addition, by providing a touch sensor module on each of the two housings 721, the operating range can be expanded.

[0491] As a touch sensor module, various touch sensors can be used. For example, capacitive, resistive, infrared, electromagnetic, surface acoustic wave, and optical sensors can be employed. In particular, it is preferable to use capacitive or optical sensors in the touch sensor module.

[0492] When using an optical touch sensor, a photoelectric conversion device (also called a photoelectric conversion element) can be used as a light-receiving device (also called a light-receiving element). One or both of inorganic semiconductors and organic semiconductors can be used in the active layer of the photoelectric conversion device.

[0493] The electronic device 800A shown in FIG24C and the electronic device 800B shown in FIG24D both include a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0494] The display unit 820 can be equipped with a display device according to one embodiment of the present invention. Therefore, an electronic device capable of displaying extremely high clarity can be realized. As a result, the user can experience a high degree of immersion.

[0495] The display unit 820 is located inside the housing 821 and is visible through the lens 832. Furthermore, by displaying different images on each of the pair of display units 820, three-dimensional display utilizing parallax can be achieved.

[0496] Both electronic device 800A and electronic device 800B can be referred to as VR-oriented electronic devices. Users who have installed electronic device 800A or electronic device 800B can see the image displayed on display unit 820 through lens 832.

[0497] Electronic devices 800A and 800B preferably have a mechanism that allows adjustment of the left and right positions of the lens 832 and the display unit 820 to position them in the most suitable way according to the user's eye position. Furthermore, it is preferable to have a mechanism that adjusts the focus by changing the distance between the lens 832 and the display unit 820.

[0498] The user can use the mounting part 823 to attach the electronic device 800A or electronic device 800B to their head. In Figure 24C, etc., the mounting part 823 is shown to have a shape similar to the temple of an eyeglass (also called a hinge, temple thread, etc.), but it is not limited to this. As long as the user can attach it, the mounting part 823 can, for example, have a helmet-type or strap-type shape.

[0499] The imaging unit 825 has the function of acquiring external information. The data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used in the imaging unit 825. In addition, multiple cameras can be set to support various viewing angles such as telephoto and wide-angle.

[0500] Note that the example shown here includes an imaging unit 825. A range sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object can be provided. In other words, the imaging unit 825 is one implementation of the detection unit. For example, an image sensor or a distance image sensor such as LiDAR (Light Detection and Ranging) can be used as the detection unit. By using images acquired by a camera and images acquired by a distance image sensor, more information can be obtained, and more precise attitude control can be achieved.

[0501] The electronic device 800A may also include a vibration mechanism used as a bone conduction headphone. For example, the structure including the vibration mechanism may be adopted as any one or more of the display unit 820, housing 821, and mounting unit 823. Thus, there is no need to separately install audio equipment such as headphones, earphones, or speakers, and one can enjoy images and sound simply by installing the electronic device 800A.

[0502] Both electronic devices 800A and 800B may include input terminals. Cables supplying image signals from image output devices and the like, as well as power for charging batteries installed in the electronic devices, can be connected to the input terminals.

[0503] An electronic device according to one embodiment of the present invention may also have the function of wirelessly communicating with the earphone 750. The earphone 750 includes a communication unit (not shown) and has a wireless communication function. The earphone 750 can receive information (e.g., audio data) from the electronic device via the wireless communication function. For example, the electronic device 700A shown in FIG24A has the function of sending information to the earphone 750 via the wireless communication function. In addition, for example, the electronic device 800A shown in FIG24C has the function of sending information to the earphone 750 via the wireless communication function.

[0504] Alternatively, the electronic device may also include an earphone unit. The electronic device 700B shown in FIG24B includes an earphone unit 727. For example, a structure in which the earphone unit 727 and the control unit are connected by a wire can be adopted. A portion of the wiring connecting the earphone unit 727 and the control unit may also be disposed inside the housing 721 or the mounting portion 723.

[0505] Similarly, the electronic device 800B shown in FIG. 24D includes an earphone unit 827. For example, a structure in which the earphone unit 827 and the control unit 824 are connected by a wire can be adopted. A portion of the wiring connecting the earphone unit 827 and the control unit 824 can also be disposed inside the housing 821 or the mounting part 823. In addition, the earphone unit 827 and the mounting part 823 can also include magnets. Thus, the earphone unit 827 can be fixed to the mounting part 823 by magnetic force, making storage easier, which is preferable.

[0506] The electronic device may also include an audio output terminal capable of connecting to headphones or headsets. Additionally, the electronic device may include one or both of an audio input terminal and an audio input mechanism. For example, a microphone or other sound-receiving device can be used as the audio input mechanism. By incorporating an audio input mechanism into the electronic device, the electronic device can be equipped with a so-called headset function.

[0507] Thus, as an embodiment of the present invention, both eyeglass type (electronic device 700A and electronic device 700B, etc.) and goggle type (electronic device 800A and electronic device 800B, etc.) are preferred electronic devices.

[0508] In addition, the electronic device of one embodiment of the present invention can transmit information to the earphone in a wired or wireless manner.

[0509] The electronic device 6500 shown in Figure 25A is a portable information terminal device that can be used as a smartphone.

[0510] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508, etc. The display unit 6502 has a touch panel function.

[0511] The display unit 6502 may use a display device according to an embodiment of the present invention.

[0512] Figure 25B is a cross-sectional view of one end of the microphone 6506 including the housing 6501.

[0513] A light-transmitting protective member 6510 is provided on one side of the display surface of the housing 6501. A display panel 6511, an optical member 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are provided in the space surrounded by the housing 6501 and the protective member 6510.

[0514] The display panel 6511, optical component 6512 and touch sensor panel 6513 are fixed to the protective component 6510 using an adhesive layer (not shown).

[0515] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and this folded portion is connected to an FPC 6515. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals provided on a printed circuit board 6517.

[0516] The display panel 6511 can use a flexible display according to one embodiment of the present invention. This allows for the realization of an extremely lightweight electronic device. Furthermore, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be installed while minimizing the thickness of the electronic device. Additionally, by folding a portion of the display panel 6511 to provide a connection portion with the FPC 6515 on the back of the pixel portion, a narrow-bezel electronic device can be realized.

[0517] Figure 25C shows an example of a television set. In the television set 7100, a display unit 7000 is assembled in the housing 7101. The structure in which the housing 7101 is supported by a bracket 7103 is shown here.

[0518] A display device to which an embodiment of the present invention can be applied to the display unit 7000.

[0519] The television 7100 shown in FIG. 25C can be operated using the operation switch provided in the housing 7101 and the separately provided remote control 7111. Alternatively, a touch sensor may be provided in the display unit 7000, allowing operation of the television 7100 by touching the display unit 7000 with a finger or the like. Furthermore, the remote control 7111 may include a display unit for displaying data output from the remote control 7111. Channel and volume adjustments can be made using the operation keys or touch panel provided in the remote control 7111, and the images displayed on the display unit 7000 can be manipulated.

[0520] In addition, the television set 7100 is equipped with a receiver and a modem. It can receive general television broadcasts by using the receiver. Furthermore, it can connect to a wired or wireless communication network by using the modem to conduct one-way (from sender to receiver) or two-way (between sender and receiver or between receivers, etc.) information communication.

[0521] Figure 25D shows an example of a notebook computer. The notebook computer 7200 includes a casing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, etc. A display unit 7000 is assembled in the casing 7211.

[0522] A display device to which an embodiment of the present invention can be applied to the display unit 7000.

[0523] Figures 25E and 25F show an example of a digital signage.

[0524] The digital signage 7300 shown in Figure 25E includes a housing 7301, a display unit 7000, and a speaker 7303, etc. In addition, it may also include LED lights, operation keys (including power switches or operation switches), connection terminals, various sensors, microphones, etc.

[0525] Figure 25F shows a digital signboard 7400 disposed on a cylindrical column 7401. The digital signboard 7400 includes a display section 7000 disposed along the curved surface of the column 7401.

[0526] In Figures 25E and 25F, a display device according to one embodiment of the present invention can be used in the display unit 7000.

[0527] The larger the display unit 7000, the more information it can provide at once. The larger the display unit 7000, the easier it is to attract people's attention, for example, it can improve the effectiveness of advertising.

[0528] By using a touch panel for the display unit 7000, not only can static or dynamic images be displayed on the display unit 7000, but users can also operate it intuitively, which is superior. In addition, when used to provide information such as route information or traffic information, the intuitive operation can improve ease of use.

[0529] As shown in Figures 25E and 25F, the digital signage 7300 or 7400 is preferably able to wirelessly communicate with a user's smartphone or other information terminal device 7311 or 7411. For example, advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal device 7311 or 7411. Furthermore, the display on the display unit 7000 can be switched by operating the information terminal device 7311 or 7411.

[0530] Furthermore, the game can be executed on the digital signage 7300 or 7400 using the screen of the information terminal device 7311 or 7411 as the operating unit (controller). Thus, multiple users can participate in the game simultaneously and enjoy the experience.

[0531] The electronic device shown in Figures 26A to 26G includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), a connection terminal 9006, a sensor 9007 (which has the function of measuring the following factors: force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, tilt, vibration, odor, or infrared radiation), a microphone 9008, etc.

[0532] In Figures 26A to 26G, a display device according to one embodiment of the present invention can be used in the display unit 9001.

[0533] The electronic devices shown in Figures 26A to 26G have various functions. For example, they may have the following functions: displaying various information (still images, moving images, and text images, etc.) on a display unit; touch panel function; displaying calendars, dates, or times, etc.; control processing via various software (programs); wireless communication function; reading and processing programs or data stored in a storage medium; etc. Note that the functions of the electronic device are not limited to the above functions, and it may have various functions. The electronic device may include multiple display units. In addition, a camera or the like may be installed in the electronic device to give it the following functions: capturing still images or moving images and storing the captured images in a storage medium (external storage medium or storage medium built into the camera); displaying the captured images on a display unit; etc.

[0534] The electronic devices shown in Figures 26A to 26G will now be described in detail.

[0535] Figure 26A is a perspective view showing a portable information terminal 9101. The portable information terminal 9101 can be used, for example, as a smartphone. Note that a speaker 9003, a connection terminal 9006, a sensor 9007, etc., can also be provided in the portable information terminal 9101. Furthermore, as a portable information terminal 9101, text or image information can be displayed on multiple surfaces. Examples of three illustrations 9050 are shown in Figure 26A. Additionally, information 9051, shown as a dashed rectangle, can be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of received emails, SNS messages, or phone calls; the subject of the email or SNS message; the sender's name; the date; the time; remaining battery level; and radio wave strength. Alternatively, illustrations 9050 can be displayed in the same locations where information 9051 is displayed.

[0536] Figure 26B is a perspective view showing a portable information terminal 9102. The portable information terminal 9102 has the function of displaying information on three or more surfaces of the display unit 9001. Here, examples are shown where information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, when the portable information terminal 9102 is placed in a jacket pocket, the user can check the information 9053 displayed in a position seen from above the portable information terminal 9102. For example, the user can check the display without taking the portable information terminal 9102 out of the pocket, thereby determining whether to answer a phone call.

[0537] Figure 26C is a perspective view showing the tablet terminal 9103. The tablet terminal 9103 can, for example, perform various application software such as mobile phone calls, emails, reading and editing articles, playing music, internet communication, and computer games. The tablet terminal 9103 includes a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the housing 9000, operation keys 9005 used as operation buttons on the left side of the housing 9000, and a connection terminal 9006 on the bottom surface.

[0538] Figure 26D is a perspective view showing a watch-type portable information terminal 9200. The portable information terminal 9200 can be used, for example, as a smartwatch (registered trademark). Furthermore, the display surface of the display unit 9001 is curved, allowing display along its curved surface. In addition, the portable information terminal 9200 can make hands-free calls, for example, by communicating with a headset capable of wireless communication. Furthermore, by using the connection terminal 9006, the portable information terminal 9200 can transmit data or charge with other information terminals. Charging can also be performed wirelessly.

[0539] Figures 26E to 26G are perspective views showing the foldable portable information terminal 9201. Figure 26E is a perspective view of the portable information terminal 9201 in its unfolded state, Figure 26G is a perspective view of its folded state, and Figure 26F is a perspective view of the intermediate state during the transition from one of the states in Figures 26E and 26G to the other. The portable information terminal 9201 offers good portability in its folded state and excellent browsing experience in its unfolded state due to its large, seamlessly integrated display area. The display unit 9001 included in the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. The display unit 9001 can be bent, for example, within a radius of curvature of 0.1 mm or more and 150 mm or less.

[0540] The personal computer 2800 shown in FIG27A includes a casing 2801, a casing 2802, a display unit 2803, a keyboard 2804, and a pointing device 2805, etc. A secondary battery 2807 is provided inside the casing 2801, and a secondary battery 2806 is provided inside the casing 2802. The display unit 2803 uses a display device according to one embodiment of the present invention and is used as a touch panel. As shown in FIG27B, the personal computer 2800 can be disassembled from the casing 2801 and the casing 2802 so that only the casing 2802 is used as a tablet terminal.

[0541] In the modified example of the personal computer shown in FIG27C, a flexible display is applied to the display unit 2803. The secondary battery 2806 can be made flexible by using a flexible film as the outer packaging. Thus, as shown in FIG27C, the outer casing 2802, the display unit 2803, and the secondary battery 2806 can be folded for use. At this time, as shown in FIG27C, a portion of the display unit 2803 can also be used as a keyboard.

[0542] In addition, the housing 2802 can be folded either in a manner where the display unit 2803 is located on the inside, as shown in FIG27D, or in a manner where the display unit 2803 is located on the outside, as shown in FIG27E.

[0543] Figure 27F is a perspective view of a vehicle steering wheel. The steering wheel 41 includes a steel rim 42, a hub 43, spokes 44, and a shaft 45. A display section 20 is provided on the surface of the hub 43. A display device according to one embodiment of the present invention can be applied to the display section 20. The lower, left, and right spokes 44 are respectively provided with a light-receiving section 20b, a plurality of light-receiving sections 20c, and a plurality of light-receiving sections 20d. By placing the finger of the hand 35 on the light-receiving section 20b, the driver's fingerprint information can be obtained and used for identification. In addition, by touching the light-receiving sections 20c and 20d, the navigation system, audio system, and communication system included in the vehicle can be operated. In addition, various operations such as adjusting the interior mirror, adjusting the rearview mirror, switching on and off the interior lighting and adjusting the brightness, and opening and closing the windows can be performed.

[0544] This embodiment can be appropriately combined with other embodiments. Example

[0545] In this embodiment, the results of comparing the low-brightness display and the high-brightness display of the display device are shown.

[0546] In this embodiment, four display devices are prepared: display device A, display device B, display device C and display device D.

[0547] Display device A employs a structure combining a series-connected light-emitting device and a color filter. The diagonal of the display section (also referred to as the display area) is 0.95 inches, the resolution is 3078 ppi, and the pixel arrangement uses a stripe arrangement of RGB colors (see Figure 1A). In addition, display device A has measures to counteract crosstalk, specifically forming pixel electrodes with a thickness of 258 nm.

[0548] The display device B adopts a structure combining a single-structure light-emitting device and a color filter, wherein the diagonal of the display section is 0.7 inches, the resolution is 3256ppi, and the pixel arrangement is a Delta arrangement of RGB three colors (see Figures 9D and 9E).

[0549] The display device C adopts a structure combining a single-structure light-emitting device and a color filter, wherein the diagonal of the display section is 0.43 inches, the resolution is 3256ppi, and the pixel arrangement adopts a stripe arrangement of RGB three colors.

[0550] In display device D, the diagonal of the display section is 0.99 inches, the resolution is 2731ppi, the pixel arrangement is a stripe arrangement of the three colors of RGB, and an SBS structure light-emitting device is used. In other words, a light-emitting device is manufactured separately for each color of light emission. Subpixels emitting blue light are provided with a light-emitting device including a light-emitting layer that emits blue light, subpixels emitting green light are provided with a light-emitting device including a light-emitting layer that emits green light, and subpixels emitting red light are provided with a light-emitting device including a light-emitting layer that emits red light. In addition, display device D has measures to counteract crosstalk, specifically by processing a portion of the EL layer into island shapes using photolithography.

[0551] The chromaticity and emission spectra of each display device when displaying red (R), green (G), and blue (B) were measured using a spectroradiometer (SR-LEDW-5N manufactured by Topcon). Additionally, the emission spectrum of each display device when displaying black (BK) was also measured. Both high-brightness and low-brightness conditions were used when displaying each color.

[0552] As a high brightness condition, the brightness values ​​of red, green, and blue are used when white is displayed on the display unit at a brightness of 100 cd / m². In other words, under high brightness conditions, one of the colors red, green, and blue is displayed at any value in the range of 0 cd / m² to 100 cd / m².

[0553] As a low-brightness condition, the brightness values ​​of red, green, and blue are used when white is displayed on the display unit at a brightness of 1 cd / m². In other words, under low-brightness conditions, one of the colors red, green, and blue is displayed at any value in the range of 0 cd / m² to 1 cd / m².

[0554] Figure 28A shows the chromaticity of display device A under high brightness conditions (A_100cd / m2) and low brightness conditions (A_1cd / m2).

[0555] Figure 28B shows the chromaticity of display device B under high brightness conditions (B_100cd / m2) and low brightness conditions (B_1cd / m2).

[0556] Figure 28C shows the chromaticity of the display device C under high brightness conditions (C_100cd / m2) and low brightness conditions (C_1cd / m2).

[0557] Figure 32 shows the chromaticity of the display device D under high brightness conditions (D_100cd / m2) and low brightness conditions (D_1cd / m2).

[0558] The color gamut of the DCI-P3 (Digital Cinema Initiatives P3) specification is also plotted in Figures 28A to 28C and Figure 32.

[0559] As shown in Figure 28A, the chromaticity of display device A hardly changes between two conditions when displaying red, green, or blue. The DCI-P3 coverage of display device A hardly changes, being 88.1% under high brightness conditions and 86.1% under low brightness conditions. This indicates that the color purity is very high regardless of the brightness.

[0560] As shown in Figure 28B, the display device B exhibits chromaticity changes on the red side under low brightness conditions. Therefore, it can be assumed that in display device B, instead of crosstalk (unintended light-emitting device emitting light), the light-emitting device's color changes to the red side. The DCI-P3 coverage in display device B is 69.0% under high brightness conditions and 22.6% under low brightness conditions, indicating a significant reduction in DCI-P3 coverage.

[0561] As shown in Figure 28C, the display device C exhibits chromaticity changes on the yellow side under low brightness conditions. In display device C, the chromaticity of both RGB values ​​changes, so crosstalk can be considered to occur. Furthermore, the variation is significant when displaying blue in monochrome, suggesting a possible change in the emitted color of the light-emitting device. The DCI-P3 coverage in display device C is 88.3% under high brightness conditions and 8.9% under low brightness conditions, indicating a substantial reduction in DCI-P3 coverage.

[0562] As shown in Figure 32, the chromaticity of display device D hardly changes between the two conditions when displaying red, green, or blue. The DCI-P3 coverage of display device D hardly changes, being 99.7% under high brightness conditions and 99.3% under low brightness conditions. This indicates that the color purity is very high regardless of the brightness.

[0563] Figures 29A and 29B show the wavelength dependence of the spectral radiance (unit: W / sr / m2 / nm) of display device A. Figure 29A shows the emission spectrum under high brightness conditions, and Figure 29B shows the emission spectrum under low brightness conditions.

[0564] Figures 30A and 30B show the wavelength dependence of the spectral radiance (unit: W / sr / m2 / nm) of display device B. Figure 30A shows the emission spectrum under high brightness conditions, and Figure 30B shows the emission spectrum under low brightness conditions.

[0565] Figures 31A and 31B show the wavelength dependence of the spectral radiance (unit: W / sr / m2 / nm) of the display device C. Figure 31A shows the emission spectrum under high brightness conditions, and Figure 31B shows the emission spectrum under low brightness conditions.

[0566] Figures 33A and 33B show the wavelength dependence of the spectral radiance (unit: W / sr / m2 / nm) of the display device D. Figure 33A shows the emission spectrum under high brightness conditions, and Figure 33B shows the emission spectrum under low brightness conditions.

[0567] As can be seen from Figures 29A and 29B, display device A does not experience color mixing under both high-brightness and low-brightness conditions. Specifically, when display device A displays red (R) under low-brightness conditions, only the light-emitting devices included in the red sub-pixels emit light to extract red light. Similarly, it can be seen that when displaying green (G) under low-brightness conditions, only the light-emitting devices included in the green sub-pixels emit light to extract green light. Furthermore, it can be seen that when displaying blue (B) under low-brightness conditions, only the light-emitting devices included in the blue sub-pixels emit light to extract blue light. In addition, when displaying black (BK), almost no light emission is observed under both high-brightness and low-brightness conditions.

[0568] Display device A uses a series-connected light-emitting device and implements countermeasures against crosstalk. Therefore, it can be seen that changes in brightness result in minimal changes in displayed color, and crosstalk is suppressed. Display device A has a very high resolution of over 3000 ppi, but no crosstalk is detected, indicating that very high display quality can be achieved.

[0569] Display device A can be described as having the following structure: when the intensity of the first emission peak in the wavelength range of 400 nm to 500 nm in the emission spectrum used to display blue at a first brightness is 1, the intensity of the second emission peak in the wavelength range of 500 nm to 700 nm in the emission spectrum is 0.5 or less. Here, the first brightness is any value in the range of 0 cd / m² to 1 cd / m².

[0570] As shown in Figure 30A, the light-emitting device of display device B is designed to maintain RGB color balance under high brightness conditions. On the other hand, as shown in Figure 30B, in display device B, the red light emission is strong under low brightness conditions. Therefore, it can be considered that the chromaticity changes between low brightness and high brightness conditions.

[0571] Specifically, when display device B displays red (R) under low brightness conditions, red emission is primarily observed. Furthermore, when displaying green (G) under low brightness conditions, red emission is observed in addition to green emission, indicating color mixing. As shown in Figure 28B, the chromaticity changes from green (G) to red (R). Additionally, it is known that when displaying blue (B) under low brightness conditions, red emission is observed in addition to blue emission, indicating color mixing. As shown in Figure 28B, the chromaticity changes from blue (B) to red (R). Furthermore, when displaying black (BK) under low brightness conditions, red emission is also observed.

[0572] Display device B uses a single-structure light-emitting device including a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer. It can be considered that: a single structure including multiple light-emitting layers is difficult to adjust carrier balance, so under low brightness conditions, carrier balance is disrupted and the light-emitting device is prone to emitting red light.

[0573] As shown in Figure 31A, no color mixing was observed in display device C under high brightness conditions. On the other hand, as shown in Figure 31B, color mixing occurred in display device C under low brightness conditions. Therefore, it can be considered that the chromaticity changes between low and high brightness conditions.

[0574] Specifically, when display device C displays red (R) under low brightness conditions, green emission is also observed in addition to red, indicating that color mixing has occurred. As shown in Figure 28C, the chromaticity changes from red (R) to the yellow side. Furthermore, when displaying green (G) under low brightness conditions, red emission is also observed in addition to green emission, indicating that color mixing has occurred. As shown in Figure 28C, the chromaticity changes from green (G) to the yellow side. Additionally, it can be seen that when displaying blue (B) under low brightness conditions, green and red emission are observed in addition to blue emission, indicating that color mixing has occurred. As shown in Figure 28C, the chromaticity changes from blue (B) to the yellow side.

[0575] The display device C uses a single-structure light-emitting device comprising a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer. It can be considered that a single structure comprising multiple light-emitting layers is difficult to adjust carrier balance, therefore, under low brightness conditions, carrier balance is disrupted, and the light-emitting device easily emits red and green light. Furthermore, it can be considered that because crosstalk occurs in the display device C, there is a change between low-brightness chromaticity and high-brightness chromaticity.

[0576] As can be seen from Figures 33A and 33B, display device D does not experience color mixing under both high-brightness and low-brightness conditions. Specifically, when display device D displays red (R) under low-brightness conditions, only the light-emitting devices included in the red sub-pixels emit light and extract red light. Similarly, it can be seen that when displaying green (G) under low-brightness conditions, only the light-emitting devices included in the green sub-pixels emit light and extract green light. Furthermore, it can be seen that when displaying blue (B) under low-brightness conditions, only the light-emitting devices included in the blue sub-pixels emit light and extract blue light. In addition, when displaying black (BK), almost no light emission is observed under both high-brightness and low-brightness conditions.

[0577] In display device D, light-emitting devices are manufactured separately for each light-emitting color, and countermeasures are formulated to address crosstalk. Therefore, it can be seen that changes in brightness result in minimal changes in displayed color, and crosstalk is also suppressed. Display device D has very high resolution, but no crosstalk is detected, indicating that very high display quality can be achieved.

[0578] As described above, it can be considered that by employing a series structure, carrier balance can be easily adjusted even in light-emitting devices comprising multiple light-emitting layers, thereby suppressing color variations over a wider brightness range. Furthermore, it can be considered that by developing countermeasures against crosstalk, color variations over a wider brightness range can be suppressed. In a display device according to one embodiment of the present invention, at least a portion of the EL layer included in the light-emitting device employing a series structure is formed in an island shape. Therefore, carrier balance can be easily adjusted and crosstalk can be suppressed. Thus, color variations over a wider brightness range can be suppressed. [Simplified Explanation of the Diagram]

[0028] [Fig. 1A] is a top view showing an example of a display device. [Fig. 1B] is a cross-sectional view showing an example of a display device. [Fig. 2A] to [Fig. 2C] are cross-sectional views showing an example of a display device. [Fig. 3A] to [Fig. 3C] are cross-sectional views showing an example of a display device. [Fig. 4] is a cross-sectional view showing an example of a display device. [Fig. 5A] to [Fig. 5C] are cross-sectional views showing an example of a display device. [Fig. 6A] to [Fig. 6F] are cross-sectional views showing an example of a display device. [Fig. 7A] to [Fig. 7D] are cross-sectional views showing an example of a method of manufacturing a display device. [Fig. 8A] to [Fig. 8C] are cross-sectional views showing an example of a method of manufacturing a display device. [Fig. 9A] to [Fig. 9F] are top views showing an example of a pixel. [Fig. 10A] to [Fig. 10H] are top views showing an example of a pixel. [Fig. 11A] to [Fig. 11J] are top views showing an example of a pixel. [Fig. 12] is a perspective view showing an example of a display device. [Fig. 13A] is a cross-sectional view showing an example of a display device. [Fig. 13B] and [Fig. 13C] are cross-sectional views showing an example of a transistor. [Fig. 14] is a cross-sectional view showing an example of a display device. [Fig. 15A] to [Fig. 15D] are cross-sectional views showing an example of a display device. [Fig. 16A] and [Fig. 16B] are perspective views showing an example of a display module. [Fig. 17A] to [Fig. 17C] are cross-sectional views showing an example of a display device. [Fig. 18] is a cross-sectional view showing an example of a display device. [Fig. 19] is a cross-sectional view showing an example of a display device. [Fig. 20] is a cross-sectional view showing an example of a display device. [Fig. 21] is a cross-sectional view showing an example of a display device. [Fig. 22] is a cross-sectional view showing an example of a display device. [Fig. 23A] to [Fig. 23F] are diagrams showing examples of the structure of a light-emitting device. Figures 24A to 24D are diagrams illustrating an example of an electronic device. Figures 25A to 25F are diagrams illustrating an example of an electronic device. Figures 26A to 26G are diagrams illustrating an example of an electronic device. Figures 27A to 27F are diagrams illustrating an example of an electronic device. Figures 28A to 28C are chromaticity diagrams of a display device. Figures 29A and 29B show the measurement results of the emission spectrum of the display device. Figures 30A and 30B show the measurement results of the emission spectrum of the display device. Figures 31A and 31B show the measurement results of the emission spectrum of the display device. Figure 32 is a chromaticity diagram of a display device. Figures 33A and 33B show the measurement results of the emission spectrum of the display device.

Claims

1. A display device, comprising: A display unit capable of full-color display, wherein the display unit includes a first sub-pixel, the first sub-pixel includes a first light-emitting device and a first color layer that transmits blue light, the first light-emitting device includes a first pixel electrode, a first EL layer on the first pixel electrode and a common electrode on the first EL layer, the first EL layer includes a first light-emitting material that emits blue light and a second light-emitting material that emits light with a longer wavelength than blue, the first EL layer includes a first light-emitting unit on the first pixel electrode, a charge-generating layer on the first light-emitting unit and a second light-emitting unit on the charge-generating layer, wherein when the intensity of the first emission peak in the wavelength range of 400 nm to 500 nm in the emission spectrum when the display unit displays blue at a first brightness is set to 1, the intensity of the second emission peak in the wavelength range of 500 nm to 700 nm in the emission spectrum is 0.5 or less, and the first brightness is any value in the range of 0 cd / m2 to 1 cd / m2.

2. The display device of claim 1, wherein the display portion includes a second sub-pixel, the second sub-pixel includes a second light-emitting device and a second color layer that transmits light of a different color than the first color layer, the second light-emitting device includes a second pixel electrode, a second EL layer on the second pixel electrode and a common electrode on the second EL layer, the first EL layer and the second EL layer having the same structure, and the first EL layer and the second EL layer being separate from each other.

3. A display device, comprising: A display unit capable of full-color display, wherein the display unit includes a first sub-pixel and a second sub-pixel. The first sub-pixel includes a first light-emitting device and a first color layer that transmits blue light. The second sub-pixel includes a second light-emitting device and a second color layer that transmits light of a different color than the first color layer. The first light-emitting device includes a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer. The second light-emitting device includes a second pixel electrode, the first EL layer on the second pixel electrode, and the common electrode on the first EL layer. The first EL layer includes a first light-emitting unit on the first pixel electrode, a charge-generating layer on the first light-emitting unit, and a second light-emitting unit on the charge-generating layer. When the intensity of the first emission peak in the wavelength range of 400 nm to 500 nm in the emission spectrum when the display unit displays blue at a first brightness is set to 1, the intensity of the second emission peak in the wavelength range of 500 nm to 700 nm in the emission spectrum is 0.5 or less, and the first brightness is any value in the range of 0 cd / m² to 1 cd / m².

4. A display device, comprising: A display unit capable of full-color display includes a first sub-pixel and a second sub-pixel. The first sub-pixel includes a first light-emitting device and a first color layer that transmits blue light. The second sub-pixel includes a second light-emitting device and a second color layer that transmits light of a different color than the first color layer. The first light-emitting device includes a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer. The second light-emitting device includes a second pixel electrode, a second EL layer on the second pixel electrode, and the common electrode on the second EL layer. The first EL layer and the second EL layer have the same structure and are separate from each other. The first EL layer includes a first light-emitting unit on the first pixel electrode, a charge-generating layer on the first light-emitting unit, and a second light-emitting unit on the charge-generating layer. When the intensity of the first emission peak in the wavelength range of 400 nm to 500 nm in the emission spectrum when the display unit displays blue at a first brightness is set to 1, the intensity of the second emission peak in the wavelength range of 500 nm to 700 nm in the emission spectrum is 0.5 or less. Furthermore, the first brightness is any value within the range of 0 cd / m2 to 1 cd / m2.

5. The display device of claim 2 or 4, wherein the first light-emitting device includes a common layer between the first EL layer and the common electrode, the second light-emitting device includes the common layer between the second EL layer and the common electrode, and the common layer includes at least one of a hole injection layer, a hole transport layer, a hole barrier layer, an electron barrier layer, an electron transport layer, and an electron injection layer.

6. The display device as claimed in claim 2 or 4, wherein the display portion includes a first insulating layer covering the side surface of the first EL layer and the side surface of the second EL layer, and the common electrode is located on the first insulating layer.

7. The display device of claim 6, wherein the first insulating layer is in contact with the side surface of the first pixel electrode and the side surface of the second pixel electrode.

8. The display device of claim 6 or 7, wherein the display portion includes a second insulating layer, the first insulating layer includes an inorganic material, and the second insulating layer includes an organic material and covers the side surface of the first EL layer and the side surface of the second EL layer through the first insulating layer.

9. The display device according to any one of requests 1 to 8, wherein the resolution of the display section is 1000ppi or higher.

10. The display device of any one of claims 1 to 9, wherein the first sub-pixel includes a lens overlapping the first light-emitting device and the first color layer.

11. The display device of any one of claims 1 to 10, wherein the first pixel electrode comprises a material that reflects visible light.

12. A display device according to any one of claims 1 to 10, wherein the first sub-pixel includes a reflective layer, the first pixel electrode includes a material that transmits visible light, and the first pixel electrode is located between the reflective layer and the first EL layer.

13. A display module, comprising: Such as the display device for any of the requests 1 to 12; And at least one of the connector and integrated circuit.

14. An electronic device comprising: Such as the display module in request item 13; And at least one of the following: casing, battery, camera, speaker, and microphone.