Indication device

Abstract

Provided is a display device having a wide viewing angle. The display device has a first light-emitting element and a second light-emitting element on a substrate. The first light-emitting element has a first pixel electrode, a first organic layer, and a common electrode, and the second light-emitting element has a second pixel electrode, a second organic layer, and a common electrode. In a top view of the substrate, the first light-emitting element has a first side and a second side shorter than the first side. The absolute value of a difference between a chromaticity difference between a chromaticity in the front direction and a chromaticity in a first direction and a chromaticity difference between the chromaticity in the front direction and a chromaticity in a second direction is 0.05 or less. A projection on the substrate in the first direction is parallel to the first side, and a projection on the substrate in the second direction is parallel to the second side. An angle formed between the first direction and the normal direction of a surface of the substrate is 70 degrees, and an angle formed between the second direction and the normal direction of the surface of the substrate is 70 degrees.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a display device. Another aspect of the present invention relates to a method for manufacturing a display device.

[0002] It should be noted that one aspect of the present invention is not limited to the above-mentioned technical field. Examples of technical fields of one aspect of the present invention disclosed herein include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting devices, input devices, input / output devices, methods for driving them, or methods for manufacturing them. A semiconductor device refers to any device that can function by utilizing semiconductor properties. [Background technology]

[0003] In recent years, there has been a growing demand for higher resolution display panels. Devices requiring high-resolution display panels include, for example, smartphones, tablet devices, and notebook computers. Furthermore, even in stationary display devices such as television sets and monitors, higher resolution is required in line with the increasing demand for higher resolution displays.

[0004] Furthermore, typical examples of display devices applicable to display panels include liquid crystal displays, organic EL (Electro Luminescence) elements, light-emitting devices equipped with light-emitting elements (also called light-emitting devices) such as light-emitting diodes (LEDs), and electronic paper that displays information using electrophoretic methods.

[0005] For example, the basic structure of an organic EL element consists of a layer containing a light-emitting organic compound sandwiched between a pair of electrodes. By applying a voltage to this element, light can be obtained from the light-emitting organic compound. Because a display device using such an organic EL element does not require a backlight, which is necessary for liquid crystal displays and the like, it is possible to realize a thin, lightweight, high-contrast, and low-power display device. For example, an example of a display device using an organic EL element is described in Patent Document 1. [Prior art documents]

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] One aspect of the present invention is to provide a display device with a wide viewing angle as one of the problems. One aspect of the present invention is to provide a display device with high color purity as one of the problems. One aspect of the present invention is to provide a display device that can be easily refined to high definition as one of the problems. One aspect of the present invention is to provide a display device having high display quality and high definition as one of the problems. One aspect of the present invention is to provide a display device with high contrast as one of the problems. One aspect of the present invention is to provide a highly reliable display device as one of the problems. One aspect of the present invention is to provide a display device having a novel configuration as one of the problems.

[0008] One aspect of the present invention is to provide a method for manufacturing the above-described display device as one of the problems. One aspect of the present invention is to provide a method for manufacturing the above-described display device with high yield as one of the problems. One aspect of the present invention is to reduce at least one of the problems of the prior art as one of the problems.

[0009] Note that the description of these problems does not prevent the existence of other problems. Note that one aspect of the present invention does not need to solve all of these problems. Note that other problems can be extracted from the descriptions of the specification, drawings, claims, etc.

Means for Solving the Problems

[0010] One aspect of the present invention is a display device having a first light-emitting element and a second light-emitting element on a substrate. The first light-emitting element has a first pixel electrode, a first organic layer, and a common electrode, and the second light-emitting element has a second pixel electrode, a second organic layer, and a common electrode. In a top view of the substrate, the first light-emitting element has a first edge and a second edge that is shorter than the first edge. The absolute value of the difference between the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction and the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction is 0.05 or less. The projection onto the substrate in the first direction is parallel to the first edge, and the projection onto the substrate in the second direction is parallel to the second edge. The angle between the first direction and the normal direction of the substrate surface is 70°, and the angle between the second direction and the normal direction of the substrate surface is 70°.

[0011] Another aspect of the present invention is a display device having a first light-emitting element and a second light-emitting element on a substrate. The first light-emitting element has a first pixel electrode, a first organic layer, and a common electrode, and the second light-emitting element has a second pixel electrode, a second organic layer, and a common electrode. In a top view of the substrate, the first light-emitting element has a first edge and a second edge that is shorter than the first edge. The ratio of the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity difference Δu'v' between the chromaticity in the first direction and the chromaticity in the front direction is 0.5 or more and 1.5 or less. The projection onto the substrate in the first direction is parallel to the first edge, and the projection onto the substrate in the second direction is parallel to the second edge. The angle between the first direction and the normal direction of the substrate surface is 70°, and the angle between the second direction and the normal direction of the substrate surface is 70°.

[0012] In the above-described display device, in a top view of the first light-emitting element, in the region where the first pixel electrode and the common electrode overlap via the light-emitting region of the first organic layer, it is preferable that the entire surface of the first pixel electrode on the first organic layer side and the entire surface of the common electrode on the first organic layer side are parallel or approximately parallel.

[0013] Preferably, the above-mentioned display device further has an insulating layer, wherein the end of the first pixel electrode and the end of the first organic layer coincide or substantially coincide, the end of the second pixel electrode and the end of the second organic layer coincide or substantially coincide, and the insulating layer has a region that is in contact with the respective sides of the first pixel electrode, the second pixel electrode, the first organic layer, and the second organic layer.

[0014] Preferably, the above-mentioned display device further has an insulating layer, the width of the first pixel electrode is smaller than the width of the first organic layer, the width of the second pixel electrode is smaller than the width of the second organic layer, the first organic layer covers the side and top surfaces of the first pixel electrode, the second organic layer covers the side and top surfaces of the second pixel electrode, and the insulating layer has a region that is in contact with a part of the top surface and a side surface of the first organic layer and the second organic layer, respectively.

[0015] Preferably, the above-mentioned display device further has an insulating layer, the width of the first pixel electrode is greater than the width of the first organic layer, the width of the second pixel electrode is greater than the width of the second organic layer, and the insulating layer has a region that is in contact with a part of the upper surface and the side surface of the first and second pixel electrodes, and with the side surface of the first and second organic layers.

[0016] The above-mentioned display device further comprises a first insulating layer and a second insulating layer, wherein the first insulating layer covers the end of the first pixel electrode, the first organic layer is provided on the first pixel electrode and on the first insulating layer, and the second insulating layer is provided on the first organic layer and on the first insulating layer, and preferably the second insulating layer has a region that is in contact with a part of the upper surface and side of the first organic layer, and a part of the upper surface of the first insulating layer.

[0017] In the above-described display device, it is preferable that the end of the first insulating layer is tapered, and the second insulating layer has a region that overlaps with the end of the first insulating layer via the first organic layer.

[0018] In the above-described display device, it is preferable that the first light-emitting element has a common layer between the first organic layer and the common electrode, and the second light-emitting element has a common layer between the second organic layer and the common electrode.

[0019] In the above-described display device, it is preferable that the common layer has either an electron transport layer or an electron injection layer, or both.

[0020] In the above-described display device, the substrate is preferably flexible, and the shape of the substrate is preferably non-rectangular. [Effects of the Invention]

[0021] According to one aspect of the present invention, a display device with a wide viewing angle can be provided. Alternatively, a display device with high color purity can be provided. Alternatively, a display device that is easily made high-resolution can be provided. Alternatively, a display device that combines high display quality and high resolution can be provided. Alternatively, a display device with high contrast can be provided. Alternatively, a highly reliable display device can be provided. Alternatively, a display device with a novel configuration can be provided.

[0022] Furthermore, according to one aspect of the present invention, a method for manufacturing the above-described display device can be provided. Alternatively, a method for manufacturing the above-described display device with a high yield can be provided. According to one aspect of the present invention, at least one of the problems of the prior art can be mitigated.

[0023] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description in the specification, drawings, claims, etc. [Brief explanation of the drawing]

[0024] Figure 1A is a schematic top view showing an example of the configuration of a display device. Figures 1B and 1C are schematic cross-sectional views showing an example of the configuration of a display device. Figures 2A to 2C are schematic cross-sectional views showing examples of the configuration of a display device. Figure 3 shows the direction when calculating the chromaticity difference. Figure 4 is a schematic top view showing an example of the configuration of a display device. Figures 5A to 5D are cross-sectional views showing examples of the configuration of a display device. Figures 6A to 6C are cross-sectional views showing examples of the configuration of a display device. Figures 7A to 7E are cross-sectional views showing examples of the configuration of a display device. Figures 8A to 8F are cross-sectional views showing examples of the configuration of a display device. Figures 9A to 9F are cross-sectional views showing examples of the configuration of a display device. Figures 10A to 10D are cross-sectional views showing examples of the configuration of a display device. Figures 11A to 11D are cross-sectional views showing examples of methods for manufacturing a display device. Figures 12A to 12C are cross-sectional views showing examples of methods for manufacturing a display device. Figures 13A to 13D are cross-sectional views showing examples of methods for manufacturing a display device. Figures 14A to 14C are cross-sectional views showing examples of methods for manufacturing a display device. Figure 15 is a perspective view showing an example of a display device. Figure 16A is a cross-sectional view showing an example of a display device. Figures 16B and 16C are cross-sectional views showing an example of a transistor. Figure 17 is a cross-sectional view showing an example of a display device. Figures 18A to 18D are cross-sectional views showing an example of a display device. Figures 19A to 19D are top views showing an example of a pixel. Figures 20A to 20D are top views showing an example of a pixel. Figures 21A to 21E are top views showing an example of a pixel. Figures 22A to 22C are top views showing an example of a pixel. Figures 23A to 23C are top views showing an example of a pixel. Figures 24A, 24B, and 24D are cross-sectional views showing examples of display devices. Figures 24C and 24E show examples of images. Figures 24F and 24G are top views showing examples of pixels. Figures 25A and 25D are cross-sectional views showing examples of the configuration of a display device. Figures 25B, 25C, 25E, and 25F are top views showing examples of pixels. Figures 26A to 26F show examples of the configuration of a light-emitting device. Figures 27A and 27B show examples of configurations for light-emitting and light-receiving devices. Figures 28A and 28B show examples of display device configurations. Figures 29A, 29C, and 29E are schematic top views of the display panel in its deployed state, and Figures 29B, 29D, and 29F are external views of a display device showing one embodiment of the present invention. Figure 30A is a schematic top view showing multiple display panels before they are superimposed, and Figure 30B is an external view of a display device showing one embodiment of the present invention. Figures 31A to 31C show examples of the configuration of a display device. Figures 32A and 32B are schematic diagrams of a car that uses a display panel. Figures 33A and 33B show examples of electronic devices that use a display panel. Figure 34 shows an example of a vehicle configuration. Figures 35A to 35F show examples of electronic devices. [Modes for carrying out the invention]

[0025] The embodiments will be described below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the embodiments can be implemented in many different ways, and their form and details can be modified in various ways without departing from the spirit and scope thereof. Accordingly, the present invention shall not be construed as being limited to the contents of the following embodiments.

[0026] In the invention described below, the same reference numerals are used in common across different drawings for identical parts or parts having similar functions, and repeated explanations are omitted. Furthermore, when referring to similar functions, the same hatching pattern may be used, and reference numerals may not be assigned.

[0027] In the figures described herein, the size of each component, the thickness of the layers, or the area may be exaggerated for clarity. Therefore, the scale is not necessarily limited to those figures.

[0028] Furthermore, ordinal numbers such as "the first," "the second," etc., used in this specification are added to avoid confusion of constituent elements and do not imply any numerical limitation.

[0029] Furthermore, in this specification, the terms "film" and "layer" are interchangeable. For example, the terms "conductive layer" or "insulating layer" may be interchangeable with the terms "conductive film" or "insulating film."

[0030] In this specification, the term "EL layer" refers to a layer (also called a light-emitting layer) provided between a pair of electrodes of a light-emitting element and containing at least a light-emitting substance, or a laminate including a light-emitting layer.

[0031] In this specification, a display panel, which is one form of a display device, has the function of displaying (outputting) images or the like on its display surface. Therefore, a display panel is one form of an output device.

[0032] Furthermore, in this specification, a display panel on which a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) is attached, or on which an IC is mounted on the board using a COG (Chip On Glass) method, may be referred to as a display panel module, display module, or simply a display panel.

[0033] Furthermore, if upper and lower numerical limits are specified in this specification, configurations in which the upper and lower numerical limits can be freely combined are also disclosed.

[0034] In this specification, "heights match or approximately match" refers to a configuration in which the heights from a reference surface (e.g., a flat surface such as the substrate surface) are equal in a cross-sectional view. For example, in the manufacturing process of semiconductor devices, planarization (typically CMP) may expose the surfaces of one or more layers. In this case, the surfaces subjected to CMP will have a configuration in which the heights from the reference surface are equal. However, the heights of the multiple layers may differ depending on the processing apparatus, processing method, or material of the surface subjected to CMP. In this specification, this case will also be treated as "heights match or approximately match." For example, if there are two layers with different heights (here referred to as a first layer and a second layer) with respect to a reference surface, if the difference between the height of the top surface of the first layer and the height of the top surface of the second layer is 20 nm or less, it is also said that the heights match or approximately match.

[0035] In this specification, "ends coincide or roughly coincide" means that, when viewed from above, at least a portion of the contours of the stacked layers overlap. This includes, for example, cases where the upper and lower layers are processed with the same mask pattern, or partially with the same mask pattern. However, strictly speaking, the contours may not overlap, and the contour of the upper layer may be located inside the contour of the lower layer, or the contour of the upper layer may be located outside the contour of the lower layer; in this case, it is also referred to as "ends coincide or roughly coincide."

[0036] (Embodiment 1) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 1 to 3.

[0037] The display device of this embodiment has a first light-emitting element and a second light-emitting element. The first light-emitting element and the second light-emitting element each have a first electrode, a light-emitting layer on the first electrode, and a second electrode on the light-emitting layer. The display device of this embodiment may further have a third light-emitting element. The third light-emitting element has a first electrode, a light-emitting layer on the first electrode, and a second electrode on the light-emitting layer.

[0038] The display device of this embodiment has a first electrode, a second electrode, and a light-emitting layer. Furthermore, the upper surface of the first electrode that overlaps with the light-emitting region of the light-emitting layer is flat, and the lower surface of the second electrode that overlaps with the light-emitting region of the light-emitting layer is flat. With this configuration, color shift is less likely to occur when the display device is viewed from an oblique direction and when the display device is viewed from the front. Furthermore, color shift is less likely to occur when the display device is viewed from a first oblique direction and when the display device is viewed from a second oblique direction. As a result, a display device with a wide viewing angle can be realized. In addition, a display device with high color purity can be realized.

[0039] For example, if an insulating layer is provided so as to cover the end of the first electrode, light may be emitted from the light-emitting layer located on the insulating layer. Furthermore, if the insulating layer in the region overlapping with the light-emitting layer has a slope, the light will be emitted in an oblique direction, which may affect the viewing angle of the display device. Specifically, the viewing angle of the display device may be narrowed. On the other hand, in one embodiment of the present invention, the light-emitting region of the light-emitting layer is flat. This makes it possible to widen the viewing angle in the horizontal (left and right) and vertical (up and down) directions. For example, the viewing angle dependence of chromaticity can be reduced in the horizontal (left and right) and vertical (up and down) directions. Furthermore, the viewing angle dependence of chromaticity in the horizontal (left and right) direction and the viewing angle dependence of chromaticity in the vertical (up and down) direction can be made to be of a similar degree.

[0040] In the CIE1976 chromaticity coordinate system, the chromaticity difference Δu'v' between the chromaticity of the light emitted by each light-emitting element in the front direction and the chromaticity in the oblique direction (the direction in which the absolute value of the inclination from the front is greater than 0° and less than 90°) is preferably 0.05 or less, and more preferably 0.02 or less. Specifically, the chromaticity difference Δu'v' between the chromaticity of the light emitted by each light-emitting element in the front direction and the chromaticity in the direction inclined from the front at 30° to 60° (more preferably 30° to 80°) is preferably 0.05 or less, and more preferably 0.02 or less.

[0041] When displaying white using the first, second, and third light-emitting elements, the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the oblique direction (direction where the absolute value of the inclination from the front is greater than 0° and less than 90°) in the CIE1976 chromaticity coordinates is preferably 0.05 or less, and more preferably 0.02 or less. Specifically, the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the direction inclined 30° to 60° (more preferably 30° to 80°) from the front is preferably 0.05 or less, and more preferably 0.02 or less. If display is performed using the first, second, and third light-emitting elements, the color displayed using the first, second, and third light-emitting elements may be a color other than white.

[0042] The chromaticity difference Δu'v' mentioned above may be calculated for a single angle selected from between 30° and 80°. For example, it may be calculated for a single angle selected from between 60° and 80°, specifically 70°. If the chromaticity difference Δu'v' is small for that angle, the viewing angle dependence of chromaticity can be considered small. Alternatively, the chromaticity difference Δu'v' mentioned above may be the average value of the chromaticity differences Δu'v' calculated over a portion or all of the range between 30° and 80°.

[0043] In the CIE1976 chromaticity coordinate system, the absolute value of the difference between the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction of the light emitted by each light-emitting element, and the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction, is preferably 0.05 or less, and more preferably 0.02 or less. Specifically, the absolute value of the difference between the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction tilted 30° to 60° (more preferably 30° to 80°) from the front, and the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction, is preferably 0.05 or less, and more preferably 0.02 or less. The first direction and the second direction will be described later.

[0044] Alternatively, in the CIE1976 chromaticity coordinate system, the ratio of the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction to the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction for the light emitted by each light-emitting element is preferably 0.5 or more and 1.5 or less, more preferably 0.6 or more and 1.3 or less, and even more preferably 0.8 or more and 1.2 or less. Specifically, the ratio of the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction to the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction tilted 30° or more and 60° or less (more preferably 30° or more and 80° or less) from the front for the light emitted by each light-emitting element is preferably 0.5 or more and 1.5 or less, more preferably 0.6 or more and 1.3 or less, and even more preferably 0.8 or more and 1.2 or less. The first direction and the second direction will be described later.

[0045] When displaying white light using the first, second, and third light-emitting elements, the absolute value of the difference between the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction, and the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction, in CIE1976 chromaticity coordinates, is preferably 0.05 or less, and more preferably 0.02 or less. Specifically, the absolute value of the difference between the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction tilted 30° to 60° (more preferably 30° to 80°) from the front, and the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction, for the light emitted by each light-emitting element, is preferably 0.05 or less, and more preferably 0.02 or less. Note that if display is made using the first, second, and third light-emitting elements, the color displayed using the first, second, and third light-emitting elements may be a color other than white.

[0046] Alternatively, when displaying white using the first light-emitting element, the second light-emitting element, and the third light-emitting element, the ratio of the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction to the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction in CIE1976 chromaticity coordinates is preferably 0.5 or more and 1.5 or less, more preferably 0.6 or more and 1.3 or less, and even more preferably 0.8 or more and 1.2 or less. Specifically, the ratio of the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction to the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction tilted 30° or more and 60° or less (more preferably 30° or more and 80° or less) from the front is preferably 0.5 or more and 1.5 or less, more preferably 0.6 or more and 1.3 or less, and even more preferably 0.8 or more and 1.2 or less. Furthermore, if the first, second, and third light-emitting elements are used for display, the color displayed using the first, second, and third light-emitting elements may be a color other than white.

[0047] The absolute value of the difference or the ratio mentioned above may be calculated for a single angle selected from 30° to 80°. For example, it may be calculated for a single angle selected from 60° to 80°, specifically 70°. If the absolute value of the difference or the ratio mentioned above is small for that angle, the viewing angle dependence of chromaticity in the horizontal (left-right) direction and the viewing angle dependence of chromaticity in the vertical (up-down) direction can be considered to be of similar magnitude. Alternatively, the absolute value of the difference or the ratio mentioned above may be the average value of the absolute values ​​of the differences or the average value of the ratios calculated over a part or all of the range from 30° to 80°, respectively.

[0048] The display device of this embodiment exhibits low viewing angle dependence in both the horizontal (left-right) and vertical (up-down) directions, and even when the display device is observed from an oblique angle, there is little decrease in contrast and change in chromaticity due to the angle. Therefore, high visibility can be obtained not only when the display device is observed from the front, but also when it is observed from an oblique angle. For example, multiple people can simultaneously observe the display device of this embodiment from various angles and recognize the information displayed on the display device. Furthermore, high visibility can be obtained even when the flexible display is bent. The display device of this embodiment can be applied to various applications such as displays for portable electronic devices, large-screen displays, and curved-shaped displays.

[0049] The display device can be configured to represent one color using three subpixels of red (R), green (G), and blue (B); four subpixels of white (R, G, B, and W); or four subpixels of yellow (R, G, B, and Y). There are no limitations on the color elements, and colors other than RGBWY (for example, cyan or magenta) may be used.

[0050] For a display device to have the configuration of one aspect of the present invention, it is preferable that the end of the first electrode is not covered by an insulating layer. In other words, it is preferable that there is no insulating layer between the first electrode and the light-emitting layer. Specifically, it is preferable that the end of the first electrode and the end of the light-emitting layer coincide or substantially coincide. Alternatively, it is preferable that the width of the first electrode is smaller than the width of the light-emitting layer.

[0051] Alternatively, for the display device to have a configuration according to one aspect of the present invention, it is preferable that the end of the first electrode is covered with an insulating layer, and that the insulating layer is in contact with the side surface of the light-emitting layer. Specifically, it is preferable that the width of the first electrode is greater than the width of the light-emitting layer, and that the insulating layer is in contact with the side surface of the first electrode, a part of the upper surface of the first electrode, and the side surface of the light-emitting layer, respectively.

[0052] Alternatively, for the display device to have a configuration according to one aspect of the present invention, it is preferable that the end of the first electrode is covered by a first insulating layer, and a second insulating layer is provided above the light-emitting layer superimposed on the first insulating layer.

[0053] <Example of display device configuration> An example of the configuration of a display device according to one aspect of the present invention will be explained with reference to Figures 1 and 2.

[0054] Figure 1A is a schematic top view of the display area 80 of the display device. The display area 80 has multiple red-emitting light-emitting elements 90R, green-emitting light-emitting elements 90G, and blue-emitting light-emitting elements 90B. In Figure 1A, the labels R, G, and B are added within the light-emitting area of ​​each light-emitting element for easy distinction.

[0055] The light-emitting elements 90R, 90G, and 90B are each arranged in a matrix. Figure 1A shows a configuration in which the light-emitting elements have a stripe arrangement. However, the arrangement method of the light-emitting elements is not limited to this, and other arrangement methods such as S-strip arrangement, delta arrangement, Bayer arrangement, and zigzag arrangement may be applied, or a pentile arrangement or diamond arrangement may be used.

[0056] [Configuration Example 1] Figure 1B is a schematic cross-sectional view corresponding to the dashed line A1-A2 in Figure 1A. Figure 1B shows schematic cross-sectional views of light-emitting element 90R, light-emitting element 90G, and light-emitting element 90B.

[0057] The light-emitting elements 90R, 90G, and 90B are provided on a layer 101 that includes a transistor (not shown). Alternatively, layer 101 is provided on a substrate (not shown). Or, layer 101 includes a substrate (not shown).

[0058] The substrate is preferably flexible. Furthermore, the shape of the substrate is preferably non-rectangular. By forming light-emitting elements on the substrate, a display device with a curved display surface can be manufactured.

[0059] Layer 101 can be provided with, for example, multiple transistors, and an insulating layer can be provided to cover these transistors, thus forming a laminated structure. Layer 101 may have recesses between adjacent light-emitting elements. For example, recesses may be provided in the insulating layer located on the outermost surface of layer 101. An example of the configuration of layer 101 will be described later.

[0060] The light-emitting element 90R has a pixel electrode 111R, an organic layer 112R, and a common electrode 113. The light-emitting element 90G has a pixel electrode 111G, an organic layer 112G, and a common electrode 113. The light-emitting element 90B has a pixel electrode 111B, an organic layer 112B, and a common electrode 113. The common electrode 113 is provided in common to the light-emitting elements 90R, 90G, and 90B.

[0061] In the following, when describing matters common to the light-emitting element 90R, light-emitting element 90G, and light-emitting element 90B, the symbols attached to the reference numerals may be omitted, and the element may simply be referred to as "light-emitting element 90." Furthermore, the light-emitting element 90 described herein may refer to one or more of the light-emitting elements 90R, 90G, and 90B.

[0062] Furthermore, in the following, when describing matters common to pixel electrodes 111R, 111G, and 111B, the symbols attached to the reference numerals may be omitted, and the term "pixel electrode 111" may be used. Also, the term "pixel electrode 111" as described herein may refer to one or more of pixel electrodes 111R, 111G, and 111B.

[0063] Furthermore, in the following, when describing matters common to organic layer 112R, organic layer 112G, and organic layer 112B, the symbols attached to the reference numerals may be omitted, and the description may simply refer to "organic layer 112." Also, the organic layer 112 described herein may refer to one or more of organic layer 112R, organic layer 112G, and organic layer 112B.

[0064] A pixel electrode 111 is provided for each light-emitting element.

[0065] Organic layer 112R has a luminescent organic compound that emits light with intensity in at least the red wavelength range. Organic layer 112G has a luminescent organic compound that emits light with intensity in at least the green wavelength range. Organic layer 112B has a luminescent organic compound that emits light with intensity in at least the blue wavelength range. Organic layers 112R, 112G, and 112B can also be called EL layers.

[0066] As shown in Figure 1B, the edge of the pixel electrode 111R and the edge of the organic layer 112R coincide or approximately coincide. The edge of the pixel electrode 111G and the edge of the organic layer 112G coincide or approximately coincide. The edge of the pixel electrode 111B and the edge of the organic layer 112B coincide or approximately coincide.

[0067] As shown in Figure 1B, a gap is provided between the two organic layers between light-emitting elements of different colors. It is preferable that the organic layers 112R, 112G, and 112B are arranged so that they do not touch each other. This effectively prevents current from flowing through two adjacent organic layers, thus preventing unintended light emission. Therefore, color purity can be increased, and a display device with high display quality can be realized.

[0068] As shown in Figure 1B, the display device has an insulating layer 119, which is provided in the gap. Specifically, the insulating layer 119 has regions that are in contact with the sides of each of the pixel electrodes 111R, 111G, 111B, organic layer 112R, organic layer 112G, and organic layer 112B. By providing the insulating layer 119, electrical short circuits between the pixel electrode 111 and the common electrode 113, and leakage current between them can be effectively suppressed.

[0069] In Figure 1B, the insulating layer 119 is shown as a single layer, but this is not the only option. For example, the insulating layer 119 may be a multilayer structure of two or more layers. Figure 1C shows a configuration in which the insulating layer 119 has two layers. The display device shown in Figure 1C has an insulating layer 119a and an insulating layer 119b on the insulating layer 119a, and the other configurations are the same as the display device shown in Figure 1B.

[0070] For example, by forming the insulating layer 119a from an inorganic material and the insulating layer 119b from an organic material, electrical short circuits between the pixel electrode 111 and the common electrode 113, as well as leakage current between them, can be suppressed even more effectively.

[0071] The common electrode 113 is provided as a continuous layer common to each light-emitting element. Furthermore, the common electrode 113 is provided on the organic layer 112R, the organic layer 112G, the organic layer 112B, and the insulating layer 119. Note that the common electrode 113 may be provided for each light-emitting element. In this case, a conductive layer functioning as wiring may be provided above each common electrode, and the conductive layer and each common electrode may be electrically connected.

[0072] In the above configuration, the light-emitting region of the organic layer 112 is the area shown by the hatched area in Figure 1B. In other words, the light-emitting region of the organic layer 112 is the entire organic layer 112.

[0073] The above configuration allows the organic layer 112 to be made flat. Furthermore, the common electrode 113 that overlaps with the light-emitting region of the organic layer 112 can be made flat. In other words, the entire upper surface of the pixel electrode 111 and the entire lower surface of the common electrode 113 that overlaps with the light-emitting region of the organic layer 112 are parallel or approximately parallel in a cross-sectional view of the light-emitting element 90. Also, in the region where the pixel electrode 111 and the common electrode 113 overlap via the light-emitting region of the organic layer 112 in a top view of the light-emitting element 90, the entire surface of the pixel electrode 111 on the organic layer 112 side and the entire surface of the common electrode 113 on the organic layer 112 side are parallel or approximately parallel in a cross-sectional view of the light-emitting element 90.

[0074] Figure 1B shows a configuration in which the end of the pixel electrode 111 and the end of the organic layer 112 coincide or roughly coincide, but the present invention is not limited to this. Examples of display device configurations different from the above configuration will be explained using Figures 2A to 2C.

[0075] [Configuration Example 2] Figure 2A is a schematic cross-sectional view corresponding to the dashed line A1-A2 in Figure 1A. The display device shown in Figure 2A differs from the display device shown in Figure 1B in that the width of the pixel electrode 111 is greater than the width of the organic layer 112. Note that the parts that overlap with the previously described Configuration Example 1 will not be explained, and only the differences will be described.

[0076] As shown in Figure 2A, the width of the pixel electrode 111R is greater than the width of the organic layer 112R. The width of the pixel electrode 111G is greater than the width of the organic layer 112G. The width of the pixel electrode 111B is greater than the width of the organic layer 112B.

[0077] As shown in Figure 2A, the insulating layer 119 has regions that are in contact with a portion of the upper surface and the side surface of each of the pixel electrodes 111R, 111G, and 111B, as well as the side surfaces of each of the organic layers 112R, 112G, and 112B.

[0078] In the above configuration, the light-emitting region of the organic layer 112 is the area shown by the diagonal lines in Figure 2A. In other words, the light-emitting region of the organic layer 112 is the entire organic layer 112.

[0079] The above configuration allows the organic layer 112 to be made flat. Furthermore, the common electrode 113 that overlaps with the light-emitting region of the organic layer 112 can be made flat. In other words, the entire upper surface of the pixel electrode 111 and the entire lower surface of the common electrode 113 that overlaps with the light-emitting region of the organic layer 112 are parallel or approximately parallel in a cross-sectional view of the light-emitting element 90. Also, in the region where the pixel electrode 111 and the common electrode 113 overlap via the light-emitting region of the organic layer 112 in a top view of the light-emitting element 90, the entire surface of the pixel electrode 111 on the organic layer 112 side and the entire surface of the common electrode 113 on the organic layer 112 side are parallel or approximately parallel in a cross-sectional view of the light-emitting element 90.

[0080] [Configuration Example 3] Figure 2B is a schematic cross-sectional view corresponding to the dashed line A1-A2 in Figure 1A. The display device shown in Figure 2B differs from the display device shown in Figure 1B in that the width of the pixel electrode 111 is smaller than the width of the organic layer 112. Note that the parts that overlap with the previously described Configuration Example 1 will not be explained, and only the differences will be described.

[0081] As shown in Figure 2B, the width of the pixel electrode 111R is smaller than the width of the organic layer 112R. The width of the pixel electrode 111G is smaller than the width of the organic layer 112G. The width of the pixel electrode 111B is smaller than the width of the organic layer 112B.

[0082] As shown in Figure 2B, the organic layer 112R is provided to cover the top and side surfaces of the pixel electrode 111R. The organic layer 112G is provided to cover the top and side surfaces of the pixel electrode 111G. The organic layer 112B is provided to cover the top and side surfaces of the pixel electrode 111B. Figure 2B shows an example where the side surface of the pixel electrode 111 is vertical, but it is not limited to this, and the end of the pixel electrode 111 may be tapered. This improves the step coverage of the organic layer 112, resulting in a highly reliable display device.

[0083] In this specification, the term "tapered end" refers to an end of an object where the angle between the side surface (front) and the surface to be formed (bottom) is greater than 0° and less than 90°, and the cross-sectional shape has a continuous increase in thickness from the end. The taper angle refers to the angle between the bottom surface (surface to be formed) and the side surface (front) at the end of the object.

[0084] As shown in Figure 2B, the insulating layer 119 has regions that are in contact with a portion of the upper surface and the side surface of each of the organic layers 112R, 112G, and 112B. This configuration suppresses the narrowing of the gap between the pixel electrode 111 and the common electrode 113 in the region that does not overlap with the pixel electrode 111. Therefore, in a top view, it is possible to suppress the emission of light from the region of the organic layer 112 that does not overlap with the pixel electrode 111. In other words, the region of the organic layer 112 that overlaps with the pixel electrode 111 (the region shown by the diagonal lines in Figure 2B) can be made into the light-emitting region of the organic layer 112.

[0085] The above configuration allows the light-emitting region of the organic layer 112 to be made flat. Furthermore, the common electrode 113 that overlaps with the light-emitting region of the organic layer 112 can be made flat. In other words, the entire upper surface of the pixel electrode 111 and the entire lower surface of the common electrode 113 that overlaps with the light-emitting region of the organic layer 112 are parallel or approximately parallel in a cross-sectional view of the light-emitting element 90. Also, in the region where the pixel electrode 111 and the common electrode 113 overlap via the light-emitting region of the organic layer 112 in a top view of the light-emitting element 90, the entire surface of the pixel electrode 111 on the organic layer 112 side and the entire surface of the common electrode 113 on the organic layer 112 side are parallel or approximately parallel in a cross-sectional view of the light-emitting element 90.

[0086] [Configuration Example 4] Figure 2C is a schematic cross-sectional view corresponding to the dashed line A1-A2 in Figure 1A. The display device shown in Figure 2C differs from the display device shown in Figure 1B in that an insulating layer 118 is provided to cover the ends of the pixel electrodes 111. Furthermore, the display device shown in Figure 2C differs from the display device shown in Figure 1B in that an insulating layer 119 is provided to cover the ends of the organic layer 112. Note that the parts that overlap with the above-mentioned Configuration Example 1 will not be explained, and only the differences will be described.

[0087] As shown in Figure 2C, the insulating layer 118 is provided on layer 101 and on the pixel electrode 111 so as to cover the end of the pixel electrode 111. In other words, the insulating layer 118 is in contact with a part of the upper surface and the side surface of the pixel electrode 111. The end of the insulating layer 118 is preferably tapered. This improves the coverage of the organic layer 112 formed on the insulating layer 118.

[0088] The organic layer 112 is provided on the pixel electrode 111 and on the insulating layer 118. Figure 2C shows a configuration in which the edges of the organic layer 112 coincide or approximately coincide with the edges of the pixel electrode 111, but the system is not limited to this configuration. The width of the pixel electrode 111 may be greater than the width of the organic layer 112, or the width of the pixel electrode 111 may be smaller than the width of the organic layer 112.

[0089] The insulating layer 119 is provided on the organic layer 112 and the insulating layer 118. The insulating layer 119 also has regions that are in contact with a part of the upper surface and side of the organic layer 112, and a part of the upper surface and side of the insulating layer 118. The regions in contact with the insulating layer 118 vary depending on the width of the organic layer 112, the shape of the insulating layer 118, etc. For example, in the display device shown in Figure 2C, the insulating layer 119 has regions that are in contact with a part of the upper surface and side of the organic layer 112, and a part of the upper surface and side of the insulating layer 118. Also, for example, when the insulating layer 118 is formed using an organic resin, the insulating layer 118 may not have recesses in regions that do not overlap with the pixel electrodes 111. In this case, the insulating layer 119 has regions that are in contact with a part of the upper surface and side of the organic layer 112, and the upper surface of the insulating layer 118.

[0090] The insulating layer 119 is preferably provided on a region of the organic layer 112 that has a slope, or on a region that overlaps with the edge of the insulating layer 118, and more preferably on a region of the organic layer 112 that has a slope, or on a region that overlaps with the edge of the insulating layer 118 via the organic layer 112. With this configuration, the distance between the pixel electrode 111 and the common electrode 113 can be increased via the region indicated by the arrow in Figure 2C (the region of the organic layer 112 that has a slope, or the region where the insulating layer 119 overlaps with the edge of the insulating layer 118). Therefore, the region of the organic layer 112 that overlaps with the region where the distance between the pixel electrode 111 and the common electrode 113 is shortest (the region indicated by the diagonal lines in Figure 2C) can be made the light-emitting region of the organic layer 112.

[0091] The above configuration allows the light-emitting region of the organic layer 112 to be made flat. Furthermore, the common electrode 113 that overlaps with the light-emitting region of the organic layer 112 can be made flat. In other words, the entire upper surface of the pixel electrode 111 and the entire lower surface of the common electrode 113 that overlaps with the light-emitting region of the organic layer 112 are parallel or approximately parallel in a cross-sectional view of the light-emitting element 90. Also, in the region where the pixel electrode 111 and the common electrode 113 overlap via the light-emitting region of the organic layer 112 in a top view of the light-emitting element 90, the entire surface of the pixel electrode 111 on the organic layer 112 side and the entire surface of the common electrode 113 on the organic layer 112 side are parallel or approximately parallel in a cross-sectional view of the light-emitting element 90.

[0092] <Regarding the chromaticity range of display devices> The display device of this embodiment has multiple light-emitting elements and can achieve full-color display. Several standard values ​​have been defined as indicators of quality in full-color display.

[0093] For example, the sRGB standard has become widely established as an international standard color space specification set by the IEC (International Electrotechnical Commission) to unify differences in color reproduction between devices such as displays, printers, digital cameras, and scanners. In the sRGB standard, the chromaticity (x,y) in the CIE 1931 chromaticity coordinate (xy chromaticity coordinate) defined by the CIE (International Commission on Illumination) is set as follows: Red (R)(x,y)=(0.640,0.330), Green (G)(x,y)=(0.300,0.600), and Blue (B)(x,y)=(0.150,0.060).

[0094] Furthermore, the chromaticity (x,y) in the CIE1931 chromaticity coordinate system (xy chromaticity coordinate system) can also be expressed in the CIE1976 chromaticity coordinate system (u'v' chromaticity coordinate system), which is intended to be approximately proportional to the distance in space, by using the following conversion formula (1).

[0095]

number

[0096] Furthermore, the NTSC standard, an analog television color gamut standard created by the National Television System Committee in the United States, defines chromaticity (x,y) as follows: Red (R)(x,y)=(0.670,0.330), Green (G)(x,y)=(0.210,0.710), and Blue (B)(x,y)=(0.140,0.080).

[0097] Furthermore, the DCI-P3 (Digital Cinema Initiatives) standard, an international unified standard for the distribution of digital films (cinema), sets the chromaticity (x,y) as follows: Red (R)(x,y)=(0.680,0.320), Green (G)(x,y)=(0.265,0.690), and Blue (B)(x,y)=(0.150,0.060).

[0098] Furthermore, the Recommendation ITU-R BT.2020 (hereinafter referred to as BT.2020), a standard used for high-definition UHDTV (Ultra High Definition Television, also known as Super Hi-Vision) established by NHK, specifies chromaticity (x,y) as follows: red (0.708, 0.292), green (0.170, 0.797), and blue (0.131, 0.046).

[0099] Various standards have been established regarding image display in this manner.

[0100] In calculating chromaticity, any of the following may be used: a colorimeter, a spectroradiometer, or an emission spectrum analyzer.

[0101] <First direction, second direction> The first and second directions described above will be explained using Figure 3. Here, the first and second directions will be mainly explained using a spherical coordinate system.

[0102] Figure 3 is a perspective view of the display area 80 of the display device. Figure 3 shows a configuration in which three light-emitting elements (light-emitting element 90R, light-emitting element 90G, and light-emitting element 90B) are arranged. The display area 80 is parallel to the surface of the substrate (not shown). Therefore, the display area 80 described below can be replaced with the substrate.

[0103] Here, we will assume that the shape of each light-emitting element is rectangular when viewed from above. That is, the top shape of each light-emitting element is assumed to be a rectangle consisting of a pair of long sides and a pair of short sides. Note that Figure 3 shows an example in which light-emitting elements 90R, 90G, and 90B have a rectangular shape when viewed from above, but it is not limited to this. It is desirable that at least one of the light-emitting elements 90R, 90G, and 90B have a rectangular shape when viewed from above. Furthermore, the top shape of each light-emitting element is not limited to a rectangle, and may be a shape other than a circle (perfect circle) or a regular polygon. For example, it may be a rectangle with rounded vertices, an oval (egg-shaped, oblong, elliptical, etc.), or a polygon with two or more sides of different lengths.

[0104] As shown in Figure 3, the z-axis is defined as the normal direction of the display area 80, the x-axis is defined as the direction perpendicular to the z-axis, and the y-axis is defined as the direction perpendicular to both the z-axis and the x-axis. In other words, the x-axis and y-axis are parallel to the display area 80. Hereafter, the plane parallel to the display area 80 may be referred to as the xy-plane.

[0105] Figure 3 illustrates the first direction 31 and the second direction 32. The first direction 31 corresponds to the first direction described above, and the second direction 32 corresponds to the second direction described above.

[0106] As shown in Figure 3, the angle between the first direction 31 and the z-axis is defined as angle 31A, and the angle between the second direction 32 and the z-axis is defined as angle 32A. Furthermore, the angle between the projection of the first direction 31 onto the xy-plane and the x-axis is defined as angle 31B, and the angle between the projection of the second direction 32 onto the xy-plane and the x-axis is defined as angle 32B.

[0107] In the CIE1976 chromaticity coordinate system described above, when calculating the absolute value of the difference between the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction of the emission of light from each light-emitting element, and the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction, the first direction 31 is set so that its projection onto the xy plane is parallel to the long side of the light-emitting element, and the second direction 32 is set so that its projection onto the xy plane is parallel to the short side of the light-emitting element. In other words, in a top view of the display area 80, the first direction 31 is parallel to the long side of the light-emitting element, and the second direction 32 is parallel to the short side of the light-emitting element. Since the light-emitting element has a rectangular shape in a top view, the angle between the long side and the short side of the light-emitting element is a right angle, so the projection of the second direction 32 onto the xy plane is perpendicular to the projection of the first direction 31 onto the xy plane.

[0108] Furthermore, in a top view of the display area 80, the first direction 31 and the second direction 32 are set such that the angle between the front direction (corresponding to the z-axis direction) and the first direction 31 is equal to the angle between the front direction and the second direction 32, and the angle between the projection of the first direction 31 onto the xy-plane and the projection of the second direction 32 onto the xy-plane is 90° or 270°. In other words, the first direction 31 and the second direction 32 are set such that the angle of angle 31A and the angle of angle 32A are equal, and the difference between the angle of angle 31B and the angle 32B is 90° or 270°.

[0109] The absolute value of the difference between the two chromaticity differences Δu'v' described above can be calculated by selecting one angle between 30° and 80° for each of angles 31A and 32A, or by using a portion or all of the range between 30° and 80°.

[0110] Furthermore, the absolute value of the inclination from the front in the second direction 32 is the same as that of the first direction 31, and the projection onto the display area 80 can be considered to be perpendicular to the projection onto the display area 80 of the first direction 31. In addition, the second direction 32 can be considered to be the first direction 31 when the display area 80 is rotated by 90° in a top view while the first direction 31 is fixed.

[0111] If the light-emitting element has a top surface shape other than a rectangle, it may not be possible to define the long side and short side. For example, if the top surface shape of the light-emitting element has an axis of symmetry, the first direction 31 may be set so that its projection onto the xy-plane is parallel to the axis of symmetry, and the second direction 32 may be set so that its projection onto the xy-plane is perpendicular to the axis of symmetry. Alternatively, the first direction 31 may be set so that its projection onto the xy-plane is parallel to the line passing through the centroid of the shape of the light-emitting element and taking the longest distance to the outer edge (contour) of that shape, and the second direction 32 may be set so that its projection onto the xy-plane is parallel to the line passing through the centroid of that shape and taking the shortest distance to the outer edge of that shape. In this case, the angle between the projection of the first direction 31 onto the xy-plane and the projection of the second direction 32 onto the xy-plane is not limited to a right angle (90° or 270°).

[0112] The same method is used when calculating the ratio of the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction to the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction for the emission of light from each light-emitting element, in the CIE1976 chromaticity coordinate system described above.

[0113] As described above, one aspect of the present invention can provide a display device with a wide viewing angle. Furthermore, it can provide a display device with high color purity. It can also provide a display device with a wide viewing angle in both the horizontal (left-right) and vertical (up-down) directions. Furthermore, it can provide a display device with high color purity in both the horizontal (left-right) and vertical (up-down) directions.

[0114] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0115] (Embodiment 2) This embodiment describes an example of the configuration and manufacturing method of a display device according to one aspect of the present invention.

[0116] One aspect of the present invention is a display device having light-emitting elements (also called light-emitting devices). For example, by having three types of light-emitting elements that emit red (R), green (G), or blue (B) light, a full-color display device can be realized.

[0117] One aspect of the present invention involves processing island-shaped EL layers, and island-shaped EL layers and active layers, into fine patterns using photolithography without the use of shadow masks such as metal masks. This makes it possible to realize a display device with high resolution and a large aperture ratio, which has been difficult to achieve until now. Furthermore, because the EL layers can be differentiated, it is possible to realize a display device with extremely vivid colors, high contrast, and high display quality.

[0118] In this specification, "island-like" refers to a state in which two or more layers made of the same material and formed in the same process are physically separated. For example, an island-like EL layer refers to a state in which the EL layer and an adjacent EL layer are physically separated.

[0119] While it is difficult to reduce the spacing between different colored EL layers, or between the EL layer and the active layer, to less than 10 μm using a metal mask formation method, the above method allows for narrowing the spacing to 3 μm or less, 2 μm or less, or even 1 μm or less. For example, by using an exposure apparatus for LSIs, the spacing can be narrowed to 500 nm or less, 200 nm or less, 100 nm or less, and even 50 nm or less. This significantly reduces the area of ​​the non-emitting region that may exist between two light-emitting elements, making it possible to approach a 100% aperture ratio. For example, an aperture ratio of 50% or more, 60% or more, 70% or more, 80% or more, and even 90% or more, can be achieved, and even less than 100%.

[0120] Furthermore, the patterns of the EL layer and the active layer themselves can be made significantly smaller compared to when a metal mask is used. Also, for example, when a metal mask is used to create different EL layers, variations in thickness occur between the center and edges of the pattern, resulting in a smaller effective area that can be used as an luminescent region relative to the total area of ​​the pattern. On the other hand, with the above manufacturing method, the pattern is formed by processing a film deposited to a uniform thickness, so the thickness can be made uniform within the pattern, and even with a fine pattern, almost the entire area can be used as an luminescent region. Therefore, with the above manufacturing method, it is possible to achieve both high resolution and a high aperture ratio.

[0121] Organic films formed using FMM (Fine Metal Mask) often have an extremely small taper angle (for example, greater than 0° and less than 30°), with the thickness decreasing towards the edges. Therefore, it can be difficult to clearly identify the sides of an organic film formed using FMM, as the sides and top surfaces are continuously connected. On the other hand, in one embodiment of the present invention, since the EL layer is processed without using FMM, the sides can be clearly identified. In particular, in one embodiment of the present invention, it is preferable that the taper angle of the EL layer is 30° or more and 120° or less, preferably 60° or more and 120° or less.

[0122] In this specification, devices fabricated using a metal mask or FMM (Fine Metal Mask, a high-resolution metal mask) may be referred to as MM (Metal Mask) structured devices. Furthermore, devices fabricated using an FMM may be referred to as FMM structured devices. Additionally, devices fabricated without using a metal mask or FMM may be referred to as MML (Metal Maskless) structured devices. Because MML structured display devices are fabricated without a metal mask, they offer greater design freedom in terms of pixel arrangement and pixel shape compared to FMM structured or MM structured display devices.

[0123] In the manufacturing method for MML-structured display devices, island-shaped EL layers are not formed by the pattern of a metal mask, but rather by processing after the EL layer has been deposited on one surface. Therefore, it is possible to realize high-definition display devices or display devices with a high aperture ratio, which have been difficult to achieve until now. Furthermore, since the EL layer can be manufactured separately for each color, it is possible to realize a display device that is extremely vivid, has high contrast, and has high display quality. In addition, by providing a sacrificial layer on the EL layer, the damage that the EL layer receives during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting element can be improved. In this specification, the sacrificial layer may also be referred to as the mask layer.

[0124] Furthermore, a display device according to one aspect of the present invention may have a structure in which no insulator is provided to cover the ends of the pixel electrodes. In other words, there is no insulator provided between the pixel electrodes and the EL layer. This configuration allows for efficient extraction of light emitted from the EL layer, thereby significantly reducing the viewing angle dependence. For example, in a display device according to one aspect of the present invention, the viewing angle (the maximum angle at which a constant contrast ratio is maintained when viewing the screen from an oblique direction) can be set to a range of 100° or more and less than 180°, preferably 150° or more and 170° or less. The above viewing angle can be applied to both the vertical and horizontal directions. By using a display device according to one aspect of the present invention, the viewing angle dependence is improved, and the visibility of the image can be enhanced.

[0125] Furthermore, when forming a display device using FMM, there may be limitations on the pixel arrangement configuration. The following explains the formation of an EL layer using FMM.

[0126] When forming an EL layer using an FMM (Fiber Masking Machine), a metal mask (also called an FMM) with openings is set opposite the substrate so that EL is deposited in the desired area during EL deposition. Then, EL deposition is performed through the FMM to deposit EL in the desired area. As the substrate size increases during EL deposition, the size and weight of the FMM also increase. In addition, heat and other forces are applied to the FMM during EL deposition, which may cause deformation of the FMM. Alternatively, there are methods that apply a certain tension to the FMM during EL deposition, so the weight and strength of the FMM are important parameters.

[0127] Therefore, when designing the pixel arrangement configuration of an FMM structure display device, it is necessary to consider the above parameters and other factors, and the design must be considered under certain limitations. On the other hand, in one embodiment of the present invention, since it is an MML structure display device, it has the advantage of a higher degree of design freedom compared to an FMM structure display device, such as the pixel arrangement configuration. Furthermore, this configuration has high compatibility with flexible devices, for example, and various circuit arrangements can be used for either the pixels or the driving circuit, or both.

[0128] In this specification, a structure in which different light-emitting layers are created or painted for each color of light-emitting element (here, blue (B), green (G), and red (R)) may be referred to as an SBS (Side By Side) structure. Also, in this specification, a light-emitting element capable of emitting white light may be referred to as a white light-emitting element. A white light-emitting element can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0129] Furthermore, light-emitting elements can be broadly classified into single structures and tandem structures. A single-structure element has one light-emitting unit between a pair of electrodes, and it is preferable that the light-emitting unit includes one or more light-emitting layers. When obtaining white light emission using two light-emitting layers, the light-emitting layers should be selected such that the light-emitting colors of each of the two layers are complementary colors. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary colors, a configuration that emits white light as a whole can be obtained. Also, when obtaining white light emission using three or more light-emitting layers, the light-emitting elements can be configured so that the light-emitting elements as a whole emit white light when the light-emitting colors of each of the three or more layers combine.

[0130] In a tandem structure, it is preferable to have two or more light-emitting units between a pair of electrodes, and each light-emitting unit includes one or more light-emitting layers. By using light-emitting layers that emit light of the same color in each light-emitting unit, the brightness per given current can be increased, and a more reliable light-emitting element can be obtained compared to a single structure. To obtain white light emission in a tandem structure, the light from the light-emitting layers of multiple light-emitting units can be combined to produce white light emission. The combination of light-emitting colors that produces white light emission is the same as in the single structure. In a tandem structure, it is preferable to provide an intermediate layer, such as a charge-generating layer, between the multiple light-emitting units.

[0131] Furthermore, when comparing the aforementioned white light-emitting elements (single or tandem structure) with SBS structure light-emitting elements, SBS structure light-emitting elements can consume less power than white light-emitting elements. If you want to keep power consumption low, it is preferable to use SBS structure light-emitting elements. On the other hand, white light-emitting elements are preferable because their manufacturing process is simpler than that of SBS structure light-emitting elements, which can lead to lower manufacturing costs or higher manufacturing yields.

[0132] The configuration of the light-emitting element in this embodiment is not particularly limited and may be a single structure or a tandem structure.

[0133] The following provides more specific examples.

[0134] [Example Configuration] Figure 4 shows a schematic top view of the display area and its surroundings of the display device 100. The display area of ​​the display device 100 has multiple red-emitting light-emitting elements 90R, green-emitting light-emitting elements 90G, and blue-emitting light-emitting elements 90B. In Figure 4, the labels R, G, and B are added within the light-emitting area of ​​each light-emitting element for easy distinction.

[0135] The light-emitting elements 90R, 90G, and 90B are each arranged in a matrix. Figure 4 shows a configuration with a stripe arrangement. Note that the arrangement method of the light-emitting elements is not limited to this, and other arrangement methods such as S-stripe arrangement, delta arrangement, Bayer arrangement, and zigzag arrangement may be applied, or a pentile arrangement or diamond arrangement may be used.

[0136] Figure 4 also shows a connecting electrode 111C that is electrically connected to the common electrode 113. The connecting electrode 111C is supplied with a potential (e.g., anode potential or cathode potential) to the common electrode 113. The connecting electrode 111C is located outside the display area where the light-emitting elements 90R and the like are arranged. The common electrode 113 is also shown as a dashed line in Figure 4.

[0137] The connecting electrode 111C can be provided along the outer perimeter of the display area. For example, it may be provided along one side of the outer perimeter of the display area, or it may be provided across two or more sides of the outer perimeter of the display area. That is, if the top surface shape of the display area is rectangular, the top surface shape of the connecting electrode 111C can be a strip, L-shape, U-shape (angle bracket shape), or square, etc.

[0138] Figure 5A is a cross-sectional view corresponding to the dashed lines A1-A2 and C1-C2 in Figure 4. Figure 5A shows cross-sectional views of the light-emitting element 90R, light-emitting element 90G, light-emitting element 90B, and the connecting portion 140. The light-emitting elements 90R, 90G, and 90B are provided on layer 101. Layer 101 is provided on a substrate (not shown). Alternatively, layer 101 includes a substrate (not shown).

[0139] Layer 101 can be provided with, for example, multiple transistors (not shown), and a laminated structure can be applied in which an insulating layer is provided to cover these transistors. Here, Figure 5A shows an example in which layer 101 does not have recesses between adjacent light-emitting elements, but it may have recesses.

[0140] It is preferable that layer 101 includes, for example, a pixel circuit, a scan line driving circuit (gate driver), and a signal line driving circuit (source driver). In addition to the above, it may also include an arithmetic circuit or a memory circuit.

[0141] The light-emitting element 90R has a pixel electrode 111R, an organic layer 112R, an organic layer 114, and a common electrode 113. The light-emitting element 90G has a pixel electrode 111G, an organic layer 112G, an organic layer 114, and a common electrode 113. The light-emitting element 90B has a pixel electrode 111B, an organic layer 112B, an organic layer 114, and a common electrode 113. The organic layer 114 and the common electrode 113 are provided in common to the light-emitting elements 90R, 90G, and 90B. The organic layer 114 can also be called a common layer.

[0142] Organic layer 112R has a luminescent organic compound that emits light with intensity in at least the red wavelength range. Organic layer 112G has a luminescent organic compound that emits light with intensity in at least the green wavelength range. Organic layer 112B has a luminescent organic compound that emits light with intensity in at least the blue wavelength range. Organic layers 112R, 112G, and 112B can also be called EL layers.

[0143] Organic layers 112R, 112G, and 112B may each have one or more of the following: an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. Organic layer 114 may have a configuration without an emissive layer. For example, organic layer 114 may have one or more of the following: an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer.

[0144] In this case, it is preferable that the uppermost layer in the laminated structure of organic layer 112R, organic layer 112G, and organic layer 112B, i.e., the layer in contact with organic layer 114, is a layer other than the light-emitting layer. For example, it is preferable to cover the light-emitting layer with an electron injection layer, electron transport layer, hole injection layer, hole transport layer, or other layer, and to have this layer in contact with organic layer 114. In this way, the reliability of the light-emitting device can be improved by protecting the upper surface of the light-emitting layer with another layer when manufacturing each light-emitting device.

[0145] Each pixel electrode 111 is provided for each light-emitting element. The common electrode 113 and the organic layer 114 are provided as a continuous layer common to each light-emitting element. A conductive film that is transparent to visible light is used on either each pixel electrode or the common electrode 113, and a conductive film that is reflective is used on the other. By making each pixel electrode transparent and the common electrode 113 reflective, a bottom-emission type display device can be made. Conversely, by making each pixel electrode reflective and the common electrode 113 transparent, a top-emission type display device can be made. Furthermore, by making both each pixel electrode and the common electrode 113 transparent, a dual-emission type display device can be made.

[0146] As shown in Figure 5A, a gap is provided between the two organic layers 112 between light-emitting elements of different colors. It is preferable that the organic layers 112R, 112G, and 112B are arranged so that they do not touch each other. This effectively prevents current from flowing through two adjacent organic layers 112, thus preventing unintended light emission. Therefore, contrast can be enhanced, and a display device with high display quality can be realized.

[0147] Organic layers 112R, 112G, and 112B preferably have a taper angle of 30° or more. Organic layers 112R, 112G, and 112B preferably have an angle between the side surface (front) and the bottom surface (formed surface) at their ends that is 30° or more and 120° or less, preferably 45° or more and 120° or less, and more preferably 60° or more and 120° or less. Alternatively, organic layers 112R, 112G, and 112B preferably have a taper angle of 90° or near that (for example, 80° or more and 100° or less).

[0148] A protective layer 121 is provided on the common electrode 113. The protective layer 121 has the function of preventing impurities such as water from diffusing to each light-emitting element from above.

[0149] The protective layer 121 can be, for example, a single-layer structure or a multilayer structure including at least an inorganic insulating film. Examples of inorganic insulating films include oxide films such as silicon oxide film, silicon oxide nitride film, silicon nitride film, silicon nitride film, aluminum oxide film, aluminum oxide nitride film, and hafnium oxide film, as well as oxide films, oxide films, or nitride films. Alternatively, semiconductor materials such as indium gallium oxide and indium gallium zinc oxide may be used as the protective layer 121.

[0150] Furthermore, a laminated film of an inorganic insulating film and an organic insulating film can also be used as the protective layer 121. For example, it is preferable to have a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films. It is also preferable that the organic insulating film functions as a planarizing film. This makes the upper surface of the organic insulating film flat, thereby improving the coverage of the inorganic insulating film on top of it and enhancing the barrier properties of the protective layer 121 against impurities. In addition, since the upper surface of the protective layer 121 is flat, it is preferable because it reduces the influence of uneven shapes caused by the structure below when a structure (e.g., a color filter, touch sensor electrodes, or lens array, etc.) is provided above the protective layer 121.

[0151] In the connection portion 140, a common electrode 113 is provided in contact with the connecting electrode 111C, and a protective layer 121 is provided covering the common electrode 113.

[0152] Figure 5A shows an example where the edge of the pixel electrode 111R coincides with or roughly coincides with the edge of the organic layer 112R, the edge of the pixel electrode 111G coincides with or roughly coincides with the edge of the organic layer 112G, and the edge of the pixel electrode 111B coincides with or roughly coincides with the edge of the organic layer 112B.

[0153] Furthermore, Figure 5A shows that the organic layer 114 is provided covering the top and side surfaces of the organic layers 112R, 112G, and 112B. The organic layer 114 prevents the pixel electrode 111 and the common electrode 113 from coming into contact and causing an electrical short circuit.

[0154] Note that the display device according to one aspect of the present invention is not limited to the configuration shown in Figure 5A. Below, an example of a display device configuration that differs in some aspects from Figure 5A will be described.

[0155] Figure 5B shows an example where the display device has an organic layer 112R, an organic layer 112G, and an organic layer 112B, as well as an insulating layer 125 provided in contact with the side surface of the pixel electrode 111. In other words, the display device shown in Figure 5B differs from the display device shown in Figure 5A in that it has an insulating layer 125. By providing the insulating layer 125, electrical short circuits between the pixel electrode 111 and the common electrode 113, and leakage current between them can be effectively suppressed.

[0156] The insulating layer 125 may also be provided in contact with the side surface of the connecting electrode 111C. Figure 5B shows an example in which the insulating layer 125 has a region in contact with a part of the upper surface and the side surface of the connecting electrode 111C.

[0157] The insulating layer 125 can be an insulating layer having an inorganic material. For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used for the insulating layer 125. The insulating layer 125 may be a single layer or a laminated structure. Examples of oxide insulating films include silicon oxide film, aluminum oxide film, magnesium oxide film, indium gallium zinc oxide film, gallium oxide film, germanium oxide film, yttrium oxide film, zirconium oxide film, lanthanum oxide film, neodymium oxide film, hafnium oxide film, and tantalum oxide film. Examples of nitride insulating films include silicon nitride film and aluminum nitride film. Examples of oxidative nitride insulating films include silicon oxidative nitride film and aluminum oxidative nitride film. Examples of nitride oxide insulating films include silicon nitride film and aluminum nitride film. In particular, by applying inorganic insulating films such as aluminum oxide films, hafnium oxide films, and silicon oxide films formed by atomic layer deposition (ALD) to the insulating layer 125, it is possible to form an insulating layer 125 with fewer pinholes and excellent function in protecting the organic layer.

[0158] In this specification, the term "oxide-nitride" refers to a material in which the oxygen content is greater than the nitrogen content, and the term "nitride oxide" refers to a material in which the nitrogen content is greater than the oxygen content. For example, when "silicon oxynitride" is written, it refers to a material in which the oxygen content is greater than the nitrogen content, and when "silicon nitride oxide" is written, it refers to a material in which the nitrogen content is greater than the oxygen content. For example, when "aluminum oxynitride" is written, it refers to a material in which the oxygen content is greater than the nitrogen content, and when "aluminum nitride oxide" is written, it refers to a material in which the nitrogen content is greater than the oxygen content.

[0159] In Figure 5C, a resin layer 126 is provided between two adjacent light-emitting elements to fill the gap between two opposing pixel electrodes and the gap between two opposing organic layers. In other words, the display device shown in Figure 5C differs from the display device shown in Figure 5A in that it has a resin layer 126. The resin layer 126 can flatten the surfaces to be formed on, such as the organic layer 114 and the common electrode 113, thereby preventing the common electrode 113 from breaking due to poor coating of the common electrode 113 at the step between adjacent light-emitting elements.

[0160] While it is preferable for the upper surface of the resin layer 126 to be flat, the surface of the resin layer 126 may be concave or convex depending on the uneven shape of the surface on which the resin layer 126 is formed, the formation conditions of the resin layer 126, etc.

[0161] The resin layer 126 may also be provided in contact with the side surface of the connecting electrode 111C. Figure 5C shows an example in which the resin layer 126 has a region that is in contact with a part of the upper surface and the side surface of the connecting electrode 111C.

[0162] As the resin layer 126, an insulating layer having an organic material can be suitably used. For example, as the resin layer 126, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be applied. Alternatively, as the resin layer 126, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin may be used. Furthermore, a photosensitive resin can be used as the resin layer 126. A photoresist may be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0163] By using a photosensitive resin, the resin layer 126 can be fabricated using only the exposure and development processes. Alternatively, the resin layer 126 may be formed using a negative-type photosensitive resin (e.g., a resist material). Furthermore, when using an insulating layer containing an organic material as the resin layer 126, it is preferable to use a material that absorbs visible light. By using a material that absorbs visible light in the resin layer 126, the light emitted from the EL layer can be absorbed by the resin layer 126, thereby suppressing light (stray light) that may leak into adjacent EL layers. Therefore, a display device with high display quality can be provided.

[0164] Furthermore, by using a colored material (for example, a material containing black pigment) as the resin layer 126, a function may be provided to block stray light from adjacent pixels and suppress color mixing.

[0165] In Figure 5D, an insulating layer 125 and a resin layer 126 are provided on the insulating layer 125. In other words, the display device shown in Figure 5D differs from the display device shown in Figure 5A in that it has an insulating layer 125 and a resin layer 126. Because the insulating layer 125 prevents the organic layer 112 and the resin layer 126 from coming into contact, impurities such as moisture contained in the resin layer 126 can be prevented from diffusing into the organic layer 112, resulting in a highly reliable display device.

[0166] Furthermore, a mechanism may be provided to improve light extraction efficiency by providing a reflective film (for example, a metal film containing one or more selected from silver, palladium, copper, titanium, and aluminum) between the insulating layer 125 and the resin layer 126, and reflecting the light emitted from the light-emitting layer with the reflective film.

[0167] The display devices shown in Figures 6A to 6C and Figures 7A to 7E differ from the display device shown in Figure 5A in that the width of the pixel electrode 111 is different from the width of the organic layer 112.

[0168] Figures 6A to 6C show an example where the width of the pixel electrode 111R is greater than the width of the organic layer 112R, the width of the pixel electrode 111G is greater than the width of the organic layer 112G, and the width of the pixel electrode 111B is greater than the width of the organic layer 112B. The organic layer 112R is located inside the edge of the pixel electrode 111R, the organic layer 112G is located inside the edge of the pixel electrode 111G, and the organic layer 112B is located inside the edge of the pixel electrode 111B.

[0169] Figure 6A shows an example where an insulating layer 125 is present. The insulating layer 125 is provided covering the side surface of the organic layer 112 of the light-emitting element, and a part of the upper surface and side surface of the pixel electrode 111.

[0170] Figure 6B shows an example in which a resin layer 126 is present. The resin layer 126 is located between two adjacent light-emitting elements and covers the sides of the organic layer 112, as well as a portion of the upper surface and sides of the pixel electrode 111.

[0171] Figure 6C shows an example where both an insulating layer 125 and a resin layer 126 are present. The insulating layer 125 is provided between the organic layer 112 and the resin layer 126.

[0172] Figures 7A to 7E show examples where the width of the pixel electrode 111R is smaller than the width of the organic layer 112R, the width of the pixel electrode 111G is smaller than the width of the organic layer 112G, and the width of the pixel electrode 111B is smaller than the width of the organic layer 112B. The edges of the organic layer 112R are located outside the edges of the pixel electrode 111R, the edges of the organic layer 112G are located outside the edges of the pixel electrode 111G, and the edges of the organic layer 112B are located outside the edges of the pixel electrode 111B.

[0173] Figure 7B shows an example having an insulating layer 125. The insulating layer 125 is provided in contact with the side surfaces of the organic layers 112 of two adjacent light-emitting elements. Note that the insulating layer 125 may also cover a portion of the top surface of the organic layers 112, not just the side surfaces.

[0174] Figure 7C shows an example having a resin layer 126. The resin layer 126 is located between two adjacent light-emitting elements and covers part of the side and top surfaces of the organic layer 112. Alternatively, the resin layer 126 may be in contact with the side surfaces of the organic layer 112 and not cover the top surface.

[0175] Figure 7D shows an example where both an insulating layer 125 and a resin layer 126 are present. The insulating layer 125 is provided between the organic layer 112 and the resin layer 126.

[0176] Figure 7E shows an example where the material has an insulating layer 124, an insulating layer 125, and a resin layer 126. An insulating layer 124 is provided between the organic layer 112 and the insulating layer 125. The insulating layer 124 is formed from a sacrificial layer provided on the organic layer 112. This sacrificial layer will be explained in the [Example of Manufacturing Method] section below.

[0177] As shown in Figure 7E, layer 101 may have recesses between adjacent light-emitting elements. For example, recesses may be provided in the insulating layer located on the outermost surface of layer 101. However, layer 101 may not have recesses between adjacent light-emitting elements.

[0178] Figures 8A to 9F show the end of the pixel electrode 111R of the light-emitting element 90R, the end of the pixel electrode 111G of the light-emitting element 90G, and magnified views of their vicinity.

[0179] Figures 8A to 8C show enlarged views of the resin layer 126 and its vicinity when the upper surface of the resin layer 126 is flat. Figure 8A shows an example where the width of the organic layer 112R is greater than that of the pixel electrode 111R, and the width of the organic layer 112G is greater than that of the pixel electrode 111G. Figure 8B shows an example where the width of the pixel electrode 111R and the width of the organic layer 112R are the same or approximately the same, and the width of the pixel electrode 111G and the width of the organic layer 112G are the same or approximately the same. Figure 8C shows an example where the width of the organic layer 112R is smaller than that of the pixel electrode 111R, and the width of the organic layer 112G is smaller than that of the pixel electrode 111G.

[0180] As shown in Figure 8A, since the organic layer 112R covers the end of the pixel electrode 111R and the organic layer 112G covers the end of the pixel electrode 111G, it is preferable that the ends of the pixel electrode 111R and the pixel electrode 111G are tapered. This improves the stepped coverage of the organic layer 112R and the organic layer 112G, resulting in a highly reliable display device.

[0181] Figures 8D to 8F show an example where the upper surface of the resin layer 126 is concave. In this case, concave portions are formed on the upper surfaces of the organic layer 114, the common electrode 113, and the protective layer 121, reflecting the concave upper surface of the resin layer 126.

[0182] Figures 9A to 9C show an example where the upper surface of the resin layer 126 is convex. In this case, convex portions are formed on the upper surfaces of the organic layer 114, the common electrode 113, and the protective layer 121, reflecting the convex upper surface of the resin layer 126.

[0183] Figures 9D to 9F show an example where a portion of the resin layer 126 covers a portion of the side and top surfaces of the organic layer 112R and a portion of the side and top surfaces of the organic layer 112G. In this case, an insulating layer 125 is provided between the resin layer 126 and a portion of the side and top surfaces of the organic layer 112R or the organic layer 112G.

[0184] Figures 9D to 9F show an example where a portion of the upper surface of the resin layer 126 is concave. In this case, the upper surfaces of the organic layer 114, the common electrode 113, and the protective layer 121 are formed with uneven surfaces that reflect the upper surface of the resin layer 126.

[0185] Figures 10A and 10B show an example having an insulating layer 118.

[0186] An insulating layer 118 is provided to cover the ends of the pixel electrodes 111. The ends of the insulating layer 118 are preferably tapered.

[0187] Furthermore, by using an organic resin for the insulating layer 118, its surface can be made gently curved. This improves the coverage of the film formed on the insulating layer 118.

[0188] Examples of materials that can be used for the insulating layer 118 include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0189] Alternatively, an inorganic insulating material may be used as the insulating layer 118. Examples of inorganic insulating materials that can be used for the insulating layer 118 include oxides, oxidized nitrides, nitride oxides, or nitrides such as silicon oxide, silicon oxidized nitride, silicon nitride, silicon oxide, aluminum oxide, aluminum oxidized nitride, or hafnium oxide. In addition, yttrium oxide, zirconium oxide, gallium oxide, tantalum oxide, magnesium oxide, lanthanum oxide, cerium oxide, and neodymium oxide may also be used.

[0190] Figure 10A shows an example having an insulating layer 118 and a resin layer 126. In other words, the display device shown in Figure 10A differs from the display device shown in Figure 5A in that it has an insulating layer 118 and a resin layer 126.

[0191] The resin layer 126 is located between two adjacent light-emitting elements and covers a portion of the upper surface and sides of the organic layer 112, as well as the upper surface of the insulating layer 118.

[0192] Figure 10B shows an example where the device has an insulating layer 118, an insulating layer 125, and a resin layer 126. In other words, the display device shown in Figure 10B differs from the display device shown in Figure 10A in that it has an insulating layer 125. The insulating layer 125 is provided between the organic layer 112 and the insulating layer 118 and the resin layer 126. Note that in the configuration shown in Figure 10B, the resin layer 126 may not be necessary.

[0193] Furthermore, as shown in Figures 5B and 5C, the insulating layer 125 or resin layer 126 provided between two opposing organic layers in two adjacent light-emitting elements corresponds to the insulating layer 119 described in Embodiment 1. Also, as shown in Figure 5D, the insulating layer 125 and resin layer 126 provided between two opposing organic layers in two adjacent light-emitting elements correspond to the insulating layer 119a and insulating layer 119b described in Embodiment 1, respectively.

[0194] [Differentiation] The following describes an example with a slightly different structure from the one described above. Note that parts that overlap with the above will be referenced and explained in more detail below.

[0195] The display device shown in Figure 10C differs from the display device shown in Figure 5C mainly in that it has conductive layers 122R, 122G, and 122B. Conductive layers 122R, 122G, and 122B function as optical adjustment layers.

[0196] The light-emitting element 90R has a conductive layer 122R between the pixel electrode 111R and the organic layer 112R. The light-emitting element 90G has a conductive layer 122G between the pixel electrode 111G and the organic layer 112G. The light-emitting element 90B has a conductive layer 122B between the pixel electrode 111B and the organic layer 112B.

[0197] Furthermore, conductive layers 122R, 122G, and 122B are all transparent to visible light. Conductive layers 122R, 122G, and 122B each have different thicknesses. This allows for different optical path lengths for each light-emitting element.

[0198] Here, a conductive film reflective to visible light is used for the pixel electrodes 111R, 111G, and 111B, and a conductive film reflective and transmittant to visible light is used for the common electrode 113. As a result, each light-emitting element realizes a so-called microcavity structure (micro-resonator structure), which intensifies light of a specific wavelength. This makes it possible to realize a display device with improved color purity.

[0199] Each optical adjustment layer can be made of a conductive material that is transparent to visible light. For example, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, indium tin oxide containing silicon, and indium zinc oxide containing silicon can be used.

[0200] Each optical adjustment layer can be formed after the pixel electrodes 111R, 111G, and 111B have been formed, but before the organic film that will become the organic layer 112 has been formed. Each optical adjustment layer may use conductive films of different thicknesses, or it may be arranged in a single-layer structure, a two-layer structure, a three-layer structure, etc., from thinnest to thickest.

[0201] Furthermore, the optical adjustment layer is not limited to the display device shown in Figure 5C, but may also be provided on each light-emitting element of the display devices shown in Figures 5A, 5B, 5D, 6A to 6C, 7A to 7E, 10A, and 10B.

[0202] The display device shown in Figure 10D differs from the display device shown in Figure 10C mainly in that it does not have an optical adjustment layer. The display device shown in Figure 10D also differs from the display device shown in Figure 5C mainly in that the thickness of each organic layer 112 is different.

[0203] The display device shown in Figure 10D is an example in which a microcavity structure is realized by varying the thicknesses of organic layers 112R, 112G, and 112B. This configuration eliminates the need for a separate optical adjustment layer, thus simplifying the manufacturing process.

[0204] For example, in the display device shown in Figure 10D, the organic layer 112R of the light-emitting element 90R, which emits the longest wavelength light, is the thickest, and the organic layer 112B of the light-emitting element 90B, which emits the shortest wavelength light, is the thinnest. However, this is not limited to this, and the thickness of each organic layer can be adjusted by considering the wavelength of light emitted by each light-emitting element, the optical properties of the layers constituting the light-emitting element, and the electrical properties of the light-emitting element.

[0205] Furthermore, the light-emitting elements of the display device shown in Figure 5C are not the only ones that can be provided with a microcavity structure by varying the thickness of the organic layer 112 in the light-emitting elements of the display devices shown in Figures 5A, 5B, 5D, 6A to 6C, 7A to 7E, 10A, and 10B.

[0206] By adding a microcavity structure to the light-emitting element, the color purity can be improved.

[0207] [Example of manufacturing method] In the following section, an example of a method for manufacturing a display device according to one aspect of the present invention will be described with reference to the drawings. Here, the display device 100 shown in Figure 7E will be used as an example.

[0208] Thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed using sputtering, chemical vapor deposition (CVD), vacuum deposition, pulsed laser deposition (PLD), ALD, and other methods. CVD methods include plasma-enhanced CVD (PECVD) and thermal CVD. One type of thermal CVD is metal-organic CVD (MOCVD). Furthermore, ALD methods include PEALD and thermal ALD.

[0209] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating.

[0210] Furthermore, when processing the thin films that constitute the display device, photolithography or the like can be used. In addition, the thin films may be processed by nanoimprint lithography, sandblasting, lift-off lithography, or the like. Alternatively, island-shaped thin films may be directly formed by a film deposition method using a shielding mask such as a metal mask.

[0211] There are two main methods of photolithography. One method involves forming a resist mask on the thin film to be processed, then processing the thin film by etching or other means, and removing the resist mask. The other method involves forming a photosensitive thin film, then exposing and developing it to process the thin film into the desired shape.

[0212] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture thereof. Other light sources such as ultraviolet light, KrF laser light, or ArF laser light can also be used. Exposure may also be performed using immersion lithography. Furthermore, extreme ultraviolet (EUV) light or X-rays may be used as the light source for exposure. An electron beam can also be used instead of the light source for exposure. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because it enables extremely fine processing. Note that a photomask is not required when exposure is performed by scanning a beam such as an electron beam.

[0213] For etching thin films, methods such as dry etching, wet etching, and sandblasting can be used.

[0214] To manufacture the display device 100, first, a layer 101 is formed on a substrate (not shown). As mentioned above, the layer 101 can be a laminated structure in which an insulating layer is provided to cover a transistor, for example.

[0215] It is preferable to use a substrate that has at least sufficient heat resistance to withstand subsequent heat treatment. When using an insulating substrate, glass substrates, quartz substrates, sapphire substrates, ceramic substrates, organic resin substrates, etc., can be used. In addition, semiconductor substrates such as single-crystal semiconductor substrates, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, and SOI substrates made from silicon or silicon carbide can be used.

[0216] Next, a conductive film is formed on layer 101 to form the pixel electrode 111 and the connecting electrode 111C. Specifically, for example, the conductive film is formed on the insulating surface of layer 101. Subsequently, a portion of the conductive film is etched away to form the pixel electrode 111R, pixel electrode 111G, pixel electrode 111B, and connecting electrode 111C on layer 101 (Figure 11A).

[0217] When using a conductive film that is reflective to visible light as a pixel electrode, it is preferable to use a material (for example, silver or aluminum) that has the highest possible reflectivity across the entire wavelength range of visible light. This not only improves the light extraction efficiency of the light-emitting element but also enhances color reproduction.

[0218] Next, an organic film 112Rf, which will later become the organic layer 112R, is formed on the pixel electrode 111R, pixel electrode 111G, pixel electrode 111B, and on layer 101 (Figure 11B). Here, it is preferable that the organic film 112Rf is provided so as not to overlap with the connecting electrode 111C. For example, by shielding the region containing the connecting electrode 111C with a metal mask and forming the organic film 112Rf, the organic film 112Rf can be formed so as not to overlap with the connecting electrode 111C. In this case, the metal mask used does not need to shield the pixel region of the display unit, so it is not necessary to use a high-resolution metal mask.

[0219] The organic film 112Rf has a film containing at least a luminescent compound. In addition, it may have a structure in which one or more films functioning as a hole injection layer, hole transport layer, hole blocking layer, electron blocking layer, electron transport layer, or electron injection layer are laminated. The organic film 112Rf can be formed by, for example, vapor deposition, sputtering, or inkjet. However, it is not limited to these, and the above-mentioned film formation methods can be used as appropriate.

[0220] Next, a sacrificial film 144Ra is formed on the organic film 112Rf, the connecting electrode 111C, and layer 101, and a sacrificial film 144Rb is formed on the sacrificial film 144Ra (Figure 11B). In other words, a two-layer stacked sacrificial film is formed on the organic film 112Rf, the connecting electrode 111C, and layer 101. The sacrificial film may be a single layer or a stacked structure of three or more layers. When forming a sacrificial film in subsequent steps, a two-layer stacked sacrificial film is formed, but it may be a single layer or a stacked structure of three or more layers. In this specification, the sacrificial film may also be referred to as a mask film.

[0221] For the formation of the sacrificial films 144Ra and 144Rb, for example, sputtering, CVD, ALD, or vacuum deposition can be used. A formation method that causes less damage to the EL layer is preferred, and for the sacrificial film 144Ra formed directly on the organic film 112Rf, it is preferable to form the sacrificial film 144Ra using the ALD method or vacuum deposition method.

[0222] As the sacrificial film 144Ra, an inorganic film such as a metal film, alloy film, metal oxide film, semiconductor film, or inorganic insulating film can be suitably used.

[0223] Furthermore, an oxide film can be used as the sacrificial film 144Ra. Typically, oxide films or oxiditride films such as silicon oxide films, silicon oxiditride films, aluminum oxide films, aluminum oxiditride films, hafnium oxide films, and hafnium oxiditride films can be used. Alternatively, a nitride film can be used as the sacrificial film 144Ra. Specifically, nitride films such as silicon nitride films, aluminum nitride films, hafnium nitride films, titanium nitride films, tantalum nitride films, tungsten nitride films, gallium nitride films, and germanium nitride films can be used. Such inorganic insulating materials can be formed using film deposition methods such as sputtering, CVD, or ALD, but the sacrificial film 144Ra formed directly on the organic film 112Rf is preferably formed using the ALD method.

[0224] Furthermore, as the sacrificial film 144Ra, metal materials such as nickel, tungsten, chromium, molybdenum, cobalt, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metal materials, can be used. In particular, it is preferable to use low-melting-point materials such as aluminum or silver.

[0225] Furthermore, metal oxides such as indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO) can be used as the sacrificial film 144Ra. In addition, indium oxide, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc. can be used. Alternatively, indium tin oxide containing silicon can also be used.

[0226] Furthermore, the above-mentioned method can also be applied when element M (where M is one or more selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) is used instead of gallium. In particular, it is preferable that M be one or more selected from gallium, aluminum, or yttrium.

[0227] As the sacrificial film 144Rb, any of the materials listed above that can be used as the sacrificial film 144Ra can be used. For example, one material can be selected as the sacrificial film 144Ra from the materials listed above that can be used as the sacrificial film 144Ra, and another material can be selected as the sacrificial film 144Rb. Alternatively, from the materials listed above that can be used as the sacrificial film 144Ra, one or more materials can be selected for the sacrificial film 144Ra, and a material other than the material selected for the sacrificial film 144Ra can be used for the sacrificial film 144Rb.

[0228] Specifically, it is preferable to use aluminum oxide formed by the ALD method as the sacrificial film 144Ra and silicon nitride formed by the sputtering method as the sacrificial film 144Rb. In this configuration, the deposition temperature when forming the film by the ALD method and the sputtering method should be between room temperature and 120°C, preferably between room temperature and 100°C, as this reduces the effect on the organic film 112Rf. Furthermore, in the case of a laminated structure of sacrificial film 144Ra and sacrificial film 144Rb, it is preferable that the stress of the laminated structure is small. Specifically, it is preferable that the stress of the laminated structure be between -500 MPa and +500 MPa, more preferably between -200 MPa and +200 MPa, as this suppresses process problems such as film delamination and peeling.

[0229] The sacrificial film 144Ra can be a film with high resistance to etching treatment of each EL film, such as the organic film 112Rf, i.e., a film with a high etching selectivity ratio. Furthermore, it is particularly preferable that the sacrificial film 144Ra be a film that can be removed by a wet etching method that causes little damage to each EL film.

[0230] Furthermore, as the sacrificial film 144Ra, a material that is soluble in a chemically stable solvent may be used, at least for the film located on top of the organic film 112Rf. In particular, a material soluble in water or alcohol can be suitably used for the sacrificial film 144Ra. When forming the sacrificial film 144Ra, it is preferable to apply it using a wet deposition method while dissolved in a solvent such as water or alcohol, and then perform a heat treatment to evaporate the solvent. At this time, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to the organic film 112Rf.

[0231] Wet film deposition methods that can be used to form the sacrificial film 144Ra include spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating.

[0232] As the sacrificial film 144Ra, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used.

[0233] For the sacrificial film 144Rb, a film with a high selectivity ratio with the sacrificial film 144Ra should be used.

[0234] It is preferable to use an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by the ALD method as the sacrificial film 144Ra, and a metallic material such as nickel, tungsten, chromium, molybdenum, cobalt, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or an alloy material containing such a metallic material, formed by the sputtering method, as the sacrificial film 144Rb. In particular, it is preferable to use tungsten formed by the sputtering method as the sacrificial film 144Rb. Alternatively, a metal oxide containing indium, such as In-Ga-Zn oxide, formed by the sputtering method, may be used as the sacrificial film 144Rb. Furthermore, an inorganic material may be used as the sacrificial film 144Rb. For example, oxide films such as silicon oxide film, silicon oxide nitride film, silicon nitride film, silicon nitride film, aluminum oxide film, aluminum oxide film, hafnium oxide film, etc., can be used.

[0235] Furthermore, an organic film that can be used for the organic film 112Rf may be used as the sacrificial film 144Rb. For example, the same organic film used for the organic film 112Rf can be used as the sacrificial film 144Rb. Using such an organic film is preferable because it allows the same deposition apparatus to be used for both the organic film 112Rf and the sacrificial film 144Rb. Moreover, the process can be simplified because the sacrificial film 144Rb can be removed simultaneously when etching the organic film 112Rf.

[0236] Next, a resist mask (not shown) is formed on the sacrificial film 144Rb at a position overlapping with the pixel electrode 111R and the connecting electrode 111C. The resist mask can be made of a resist material containing a photosensitive resin, such as a positive-type resist material or a negative-type resist material.

[0237] Next, portions of the sacrificial film 144Rb and sacrificial film 144Ra that are not covered by the resist mask are removed by etching to form island-shaped or strip-shaped sacrificial layers 145Rb and 145Ra (Figure 11C). As shown in Figure 11C, the sacrificial layers 145Rb and 145Ra can be formed, for example, on the pixel electrode 111R and on the connecting electrode 111C.

[0238] Here, it is preferable to remove a portion of the sacrificial film 144Rb by etching using the resist mask described above, form a sacrificial layer 145Rb, then remove the resist mask, and subsequently etch the sacrificial film 144Ra using the sacrificial layer 145Rb as a hard mask. In this case, it is preferable to use etching conditions that have a high selectivity ratio with respect to the sacrificial film 144Ra for etching the sacrificial film 144Rb. For etching to form the hard mask, either a wet etching method or a dry etching method can be used, but by using a dry etching method, pattern reduction can be suppressed.

[0239] The sacrificial films 144Ra and 144Rb, as well as the resist mask, can be processed by wet etching or dry etching. For example, the sacrificial films 144Ra and 144Rb can be processed by dry etching using a fluorine-containing gas. The resist mask can be removed by dry etching (also known as plasma ashing) using an oxygen-containing gas (also known as oxygen gas).

[0240] When etching the sacrificial film 144Ra using the sacrificial layer 145Rb as a hard mask, the resist mask can be removed while the organic film 112Rf is covered by the sacrificial film 144Ra. For example, if the organic film 112Rf comes into contact with oxygen, it may adversely affect the electrical characteristics of the light-emitting element 90R. Therefore, when removing the resist mask using a method that uses oxygen gas, such as plasma ashing, it is preferable to etch the sacrificial film 144Ra using the sacrificial layer 145Rb as a hard mask.

[0241] Next, a portion of the organic film 112Rf not covered by the sacrificial layer 145Ra is removed by etching to form island-shaped or strip-shaped organic layers 112R (Figure 11D).

[0242] Using a dry etching method with oxygen gas to etch the organic film 112Rf increases the etching rate. Therefore, etching can be performed under low power conditions while maintaining a sufficiently fast etching rate, thereby reducing damage to the organic film 112Rf due to etching. Furthermore, problems such as the adhesion of reaction products generated during etching to the organic layer 112R can be suppressed.

[0243] On the other hand, etching the organic film 112Rf using a dry etching method with an etching gas that does not contain oxygen as its main component suppresses the deterioration of the organic film 112Rf, making the display device 100 a highly reliable display device. Examples of etching gases that do not contain oxygen as their main component include gases containing carbon tetrafluoride (CF4), C4F8, SF6, CHF3, Cl2, H2O, BCl3, etc., or gases containing group 18 elements such as He. In addition, a mixed gas of the above gas and an oxygen-free diluent gas can be used as the etching gas. Note that etching of the organic film 112Rf is not limited to the above, and may be carried out by a dry etching method using other gases or by a wet etching method.

[0244] When an organic layer 112R is formed by etching the organic film 112Rf, if impurities are attached to the side surface of the organic layer 112R, these impurities may penetrate into the interior of the organic layer 112R in subsequent processes. This may reduce the reliability of the display device 100. Therefore, it is preferable to remove impurities attached to the surface of the organic layer 112R after its formation, as this can improve the reliability of the display device 100.

[0245] Impurities adhering to the surface of the organic layer 112R can be removed, for example, by irradiating the surface of the organic layer 112R with an inert gas. Immediately after the formation of the organic layer 112R, the surface of the organic layer 112R is exposed. Specifically, the sides of the organic layer 112R are exposed. Therefore, after the formation of the organic layer 112R, if the substrate on which the organic layer 112R is formed is placed under an inert gas atmosphere, impurities adhering to the organic layer 112R can be removed. As the inert gas, one or more selected from, for example, Group 18 elements (typically helium, neon, argon, xenon, and krypton, etc.) and nitrogen can be used.

[0246] Incidentally, in the process shown in Figures 11C and 11D, etching the organic film 112Rf using an oxygen-containing gas may change the surface state of the pixel electrodes 111G and 111B. For example, the surfaces of the pixel electrodes 111G and 111B may become hydrophilic. For example, if the upper surface of the pixel electrodes 111G and 111B is a layer containing indium tin oxide, etching the organic film 112Rf using an oxygen-containing gas will make the indium tin oxide-containing layer hydrophilic. Here, the organic film formed in a later step to have a region in contact with the pixel electrode 111G, and the organic film formed to have a region in contact with the pixel electrode 111B, are, for example, hydrophobic. The adhesion between a hydrophilic surface and a hydrophobic surface is lower than the adhesion between hydrophilic surfaces and between hydrophobic surfaces. Therefore, if the surfaces of the pixel electrodes 111G and 111B are hydrophilic, the adhesion with the organic film formed in a later step may be low. Therefore, in subsequent processes, the organic film may peel off at the interface with the pixel electrode 111G or the interface with the pixel electrode 111B. Furthermore, if the organic film 112Rf is etched using an oxygen-containing gas, in addition to the above-mentioned changes in surface condition, the work function of the surfaces of the pixel electrode 111G and the pixel electrode 111B may change.

[0247] Therefore, by performing a hydrophobic treatment on the surfaces of the pixel electrode 111G and the pixel electrode 111B, peeling of the organic film formed in a later process can be suppressed. Thus, the display device 100 can be made into a highly reliable display device. In addition, the yield in the manufacturing of the display device 100 can be increased, making the display device 100 a low-cost display device.

[0248] Hydrophobic treatment can be performed, for example, by fluorine modification of the pixel electrodes 111G and 111B. Fluorine modification can be performed, for example, by treatment with a fluorine-containing gas, heat treatment, or plasma treatment in a fluorine-containing gas atmosphere. As the fluorine-containing gas, for example, fluorine gas can be used, or fluorocarbon gas can be used. As the fluorocarbon gas, for example, lower fluorinated carbon gases such as CF4 gas, C4F6 gas, C2F6 gas, C4F8 gas, and C5F8 can be used. In addition, as the fluorine-containing gas, for example, SF6 gas, NF3 gas, CHF3 gas, etc. can be used. Furthermore, helium gas, argon gas, or hydrogen gas can be added to these gases as appropriate.

[0249] Furthermore, the surfaces of the pixel electrodes 111G and 111B can be made hydrophobic by performing plasma treatment in a gas atmosphere containing a group 18 element such as argon, followed by treatment with a silylation agent. Hexamethyldisilazane (HMDS), trimethylsilylimidazole (TMSI), etc., can be used as silylation agents. In addition, the surfaces of the pixel electrodes 111G and 111B can also be made hydrophobic by performing plasma treatment in a gas atmosphere containing a group 18 element such as argon, followed by treatment with a silane coupling agent.

[0250] By performing plasma treatment on the surfaces of pixel electrodes 111G and 111B in a gas atmosphere containing a group 18 element such as argon, damage can be inflicted on the surfaces of pixel electrodes 111G and 111B. This makes it easier for methyl groups contained in silylation agents such as HMDS to bond to the surfaces of pixel electrodes 111G and 111B. It also facilitates silane coupling by silane coupling agents. As a result, by performing plasma treatment on the surfaces of pixel electrodes 111G and 111B in a gas atmosphere containing a group 18 element such as argon, followed by treatment with a silylation agent or a silane coupling agent, the surfaces of pixel electrodes 111G and 111B can be made hydrophobic.

[0251] Treatment using a silylation agent or silane coupling agent can be carried out by applying the silylation agent or silane coupling agent using, for example, a spin coating method or a dip method. Alternatively, treatment using a silylation agent or silane coupling agent can be carried out by forming a film containing a silylation agent or a film containing a silane coupling agent on the pixel electrode 111G and the pixel electrode 111B using, for example, a vapor phase method. In the vapor phase method, first, the silylation agent or silane coupling agent is introduced into the atmosphere by volatilizing the material containing the silylation agent or the material containing the silane coupling agent. Subsequently, the substrate on which the pixel electrode 111G and the pixel electrode 111B are formed is placed in the atmosphere. This allows a film containing a silylation agent or silane coupling agent to be formed on the pixel electrode 111G and the pixel electrode 111B, and the surfaces of the pixel electrode 111G and the pixel electrode 111B can be made hydrophobic.

[0252] Next, an organic film 112Gf, which will later become the organic layer 112G, is formed on the sacrificial layer 145Rb, on the pixel electrode 111G, on the pixel electrode 111B, and on layer 101. By forming the organic film 112Gf after the formation of the sacrificial layer 145Rb, it is possible to prevent the organic film 112Gf from coming into contact with the upper surface of the organic layer 112R. For details on the formation of the organic film 112Gf, etc., please refer to the description of the formation of the organic film 112Rf, etc.

[0253] Next, a sacrificial film 144Ga is formed on the organic film 112Gf and on the sacrificial layer 145Rb, and a sacrificial film 144Gb is formed on the sacrificial film 144Ga (Figure 12A). Subsequently, a resist mask (not shown) is formed on the sacrificial film 144Gb at a position overlapping with the pixel electrode 111G. For details on the formation of the sacrificial film 144Ga, the sacrificial film 144Gb, and the resist mask, refer to the descriptions of the formation of the sacrificial film 144Ra, the sacrificial film 144Rb, and the resist mask provided on the sacrificial film 144Rb, respectively.

[0254] Next, portions of the sacrificial film 144Gb and sacrificial film 144Ga that are not covered by the resist mask are removed by etching to form island-shaped or strip-shaped sacrificial layers 145Gb and 145Ga. The resist mask is then removed (Figure 12B). Here, the sacrificial layers 145Gb and 145Ga can be formed on the pixel electrode 111G. For details on the formation of the sacrificial layers 145Gb and 145Ga, and the removal of the resist mask, etc., refer to the descriptions of the formation of the sacrificial layer 145Rb and 145Ra, and the removal of the resist mask provided on the sacrificial film 144Rb.

[0255] Next, a portion of the organic film 112Gf not covered by the sacrificial layer 145Ga is removed by etching to form island-shaped or strip-shaped organic layers 112G (Figure 12C). For details on the formation of organic layers 112G, please refer to the description of the formation of organic layer 112R. In addition, it is preferable to remove impurities adhering to the surface of organic layer 112G, similar to organic layer 112R. For example, after the formation of organic layer 112G, placing the substrate on which the organic layer 112G is formed under an inert gas atmosphere can remove impurities adhering to organic layer 112G.

[0256] Subsequently, an organic film 112Bf, which will later become the organic layer 112B, is formed on the sacrificial layer 145Rb, on the sacrificial layer 145Gb, on the pixel electrode 111B, and on the layer 101. By forming the organic film 112Bf after the formation of the sacrificial layer 145Gb, it is possible to prevent the organic film 112Bf from contacting the upper surface of the organic layer 112G. Regarding the formation of the organic film 112Bf and the like, reference can be made to the description of the formation of the organic film 112Rf and the like.

[0257] Next, a sacrificial film 144Ba is formed on the organic film 112Bf and on the sacrificial layer 145Rb, and a sacrificial film 144Bb is formed on the sacrificial film 144Ba (FIG. 13A). Then, a resist mask (not shown) is formed at a position overlapping the pixel electrode 111B on the sacrificial film 144Bb. Regarding the formation of the sacrificial film 144Ba, the sacrificial film 144Bb, and the above resist mask, reference can be made to the descriptions of the formation of the sacrificial films 144Ra, 144Rb, and the resist mask provided on the sacrificial film 144Rb, respectively.

[0258] Subsequently, a portion of the sacrificial film 144Bb and the sacrificial film 144Ba that is not covered by the resist mask is removed by etching to form island-shaped or strip-shaped sacrificial layers 145Bb and 145Ba. Also, the resist mask is removed (FIG. 13B). Here, the sacrificial layers 145Bb and 145Ba can be formed on the pixel electrode 111B. Regarding the formation of the sacrificial layers 145Bb and 145Ba and the removal of the resist mask and the like, reference can be made to the descriptions of the formation of the sacrificial layers 145Rb and 145Ra and the removal of the resist mask provided on the sacrificial film 144Rb.

[0259] Subsequently, a part of the organic film 112Bf not covered by the sacrificial layer 145Ba is removed by etching to form an island-shaped or strip-shaped organic layer 112B (FIG. 13C). For the formation of the organic layer 112B and the like, reference can be made to the description of the formation of the organic layer 112R and the like. Similarly to the organic layer 112R and the organic layer 112G, it is preferable to remove the impurities adhering to the surface of the organic layer 112B. For example, after the formation of the organic layer 112B, for example, when the substrate on which the organic layer 112B is formed is placed in an inert gas atmosphere, the impurities adhering to the organic layer 112B can be removed.

[0260] Subsequently, the sacrificial layer 145Rb, the sacrificial layer 145Gb, and the sacrificial layer 145Bb are removed using etching or the like (FIG. 13D). For the etching of the sacrificial layer 145Rb, the sacrificial layer 145Gb, and the sacrificial layer 145Bb, it is preferable to use conditions with a high selectivity ratio with respect to the sacrificial layer 145Ra, the sacrificial layer 145Ga, and the sacrificial layer 145Ba. Note that there may be cases where the removal of the sacrificial layer 145Rb, the sacrificial layer 145Gb, and the sacrificial layer 145Bb may not be performed.

[0261] Subsequently, an insulating film 125f that will later become the insulating layer 125 is formed on the sacrificial layer 145Ra, on the sacrificial layer 145Ga, on the sacrificial layer 145Ba, and on the layer 101 (FIG. 14A).

[0262] The insulating film 125f is preferably formed by a method with high coverage. For example, the insulating film 125f can be formed by the ALD method. Note that the insulating film 125f may be formed by a sputtering method, a CVD method, a PLD method, or the like.

[0263] An inorganic insulating material can be used as the insulating film 125f. For example, an oxide, an oxynitride, a nitroxide, or a nitride can be used as the insulating film 125f, and it can include at least one of, for example, aluminum oxide, silicon oxide, silicon oxynitride, silicon nitroxide, silicon nitride, aluminum oxynitride, hafnium oxide, and the like.

[0264] The insulating film 125f is preferably deposited such that its thickness is 1 nm or more and 60 nm or less, more preferably 1 nm or more and 40 nm or less, and even more preferably 5 nm or more and 20 nm or less.

[0265] Next, an insulating film, which will later become a resin layer 126, is formed on the insulating film 125f. It is preferable to use an insulating film containing an organic material as the insulating film, and it is preferable to use a resin as the organic material. Furthermore, a photosensitive resin can be used as the insulating film. The photosensitive resin can be a positive-type material or a negative-type material.

[0266] When a photosensitive resin is used as the insulating film, the insulating film can be formed using a spin coating method, spray method, screen printing method, or paint method, etc.

[0267] The insulating film described above may be planarized. It may also have gentle irregularities that reflect the unevenness of the surface to which it is formed.

[0268] Next, the resin layer 126 is formed by processing the insulating film (Figure 14A). By using a photosensitive resin as the insulating film, the resin layer 126 can be formed without providing an etching mask such as a resist mask or a hard mask. Furthermore, since the photosensitive resin can be processed only by exposure and development, the resin layer 126 can be formed without using a dry etching method or the like. Thus, the process can be simplified. In addition, damage to the organic layer 112 due to etching of the insulating film can be reduced. Furthermore, a portion of the upper part of the resin layer 126 may be etched to adjust the surface height.

[0269] Alternatively, a resin layer 126 may be formed by etching the upper surface of the insulating film in a substantially uniform manner. This process of uniform etching and planarization is also called etch-back.

[0270] In forming the resin layer 126, the exposure and development process and the etch-back process may be used in combination.

[0271] Next, the sacrificial layers 145Ra, 145Ga, 145Ba, and insulating film 125f are etched to expose at least a portion of the upper surfaces of the organic layer 112R, organic layer 112G, organic layer 112B, and connecting electrode 111C (Figure 14B). At this time, the insulating layer 125 is formed from the insulating film 125f. The insulating layer 125 is formed to have a region in contact with the side surface of the resin layer 126 and a region in contact with the lower surface of the resin layer 126.

[0272] It is preferable to remove a portion of each of the sacrificial layers 145Ra, 145Ga, and 145Ba in a manner that causes as little damage as possible to the organic layer 112, for example, by using a wet etching method. Note that a portion of the sacrificial layer 145Ra may remain on the organic layer 112R, a portion of the sacrificial layer 145Ga may remain on the organic layer 112G, and a portion of the sacrificial layer 145Ba may remain on the organic layer 112B.

[0273] Next, a vacuum bake treatment is performed to remove water and other substances adsorbed on the surfaces of organic layer 112R, organic layer 112G, and organic layer 112B. The vacuum bake is preferably performed within a temperature range that does not alter the organic compounds contained in organic layer 112R, organic layer 112G, and organic layer 112B, for example, between 70°C and 120°C, more preferably between 80°C and 100°C. However, if there is little water or other substances adsorbed on the surfaces of organic layer 112R, organic layer 112G, and organic layer 112B, and the impact on the reliability of the display device 100 is minimal, the vacuum bake treatment may not be necessary.

[0274] Next, an organic layer 114 is formed on the organic layer 112R, the organic layer 112G, the organic layer 112B, and the resin layer 126. As described above, the organic layer 114 has at least one of the following: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, or an electron injection layer, for example, an electron injection layer or a hole injection layer. The organic layer 114 can be formed by, for example, a vapor deposition method, a sputtering method, or an inkjet method. If the organic layer 114 is not provided on the connecting electrode 111C, a metal mask that shields the connecting electrode 111C can be used when forming the organic layer 114. In this case, the metal mask used does not need to shield the pixel area of ​​the display unit, so there is no need to use a high-resolution metal mask.

[0275] Next, a common electrode 113 is formed on the organic layer 114. The common electrode 113 can be formed by, for example, sputtering or vacuum deposition. Through the above steps, the light-emitting element 90R, light-emitting element 90G, and light-emitting element 90B can be fabricated.

[0276] Next, a protective layer 121 is formed on the common electrode 113 (Figure 14C). When an inorganic insulating film is used as the protective layer 121, it is preferable to form the protective layer 121 using, for example, a sputtering method, a CVD method, or an ALD method. When an organic insulating film is used as the protective layer 121, it is preferable to form the protective layer 121 using, for example, an inkjet method, because a uniform film can be formed in the desired area.

[0277] The display device 100 can be manufactured through the above process.

[0278] As described above, in the method for manufacturing a display device according to one embodiment of the present invention, an EL layer is formed separately without using a shadow mask such as a metal mask, for example, by using a photolithography method and an etching method. As a result, the pattern of the EL layer can be made into a fine pattern. Therefore, by the method for manufacturing a display device according to one embodiment of the present invention, a display device with high definition and a high aperture ratio can be manufactured. In addition, a high-resolution display device and a large-sized display device can be manufactured. Furthermore, since the EL layer can be formed separately, a display device that is extremely vivid, has high contrast, and has high display quality can be manufactured.

[0279] This embodiment can be implemented in appropriate combination with at least a part of other embodiments described in this specification.

[0280] (Embodiment 3) In this embodiment, a display device according to one embodiment of the present invention will be described with reference to FIGS. 15 to 23.

[0281] The display device of this embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of this embodiment can be used, for example, in electronic devices having a relatively large screen such as a television device, a desktop or notebook personal computer, a monitor for a computer, a digital signage, a large game machine such as a pachinko machine, as well as in a digital camera, a digital video camera, a digital photo frame, a mobile phone, a portable game machine, a portable information terminal, and a display unit of an audio playback device.

[0282] [Display Device 100A] FIG. 15 shows a perspective view of the display device 100A, and FIG. 16A shows a cross-sectional view of the display device 100A.

[0283] The display device 100A has a configuration in which a substrate 152 and a substrate 151 are bonded together. In FIG. 15, the substrate 152 is indicated by a broken line.

[0284] The display device 100A includes a display unit 162, a circuit 164, wiring 165, etc. Figure 15 shows an example in which IC 173 and FPC 172 are mounted on the display device 100A. Therefore, the configuration shown in Figure 15 can also be described as a display module having the display device 100A, an IC (integrated circuit), and an FPC.

[0285] For example, a scan line drive circuit can be used as circuit 164.

[0286] Wiring 165 has the function of supplying signals and power to the display unit 162 and the circuit 164. These signals and power are input to wiring 165 from an external source via FPC 172 or from IC 173.

[0287] Figure 15 shows an example in which IC 173 is provided on the substrate 151 using the COG method or COF (Chip On Film) method. IC 173 can be an IC having, for example, a scan line drive circuit or a signal line drive circuit. Note that the display device 100A and the display module may be configured without an IC. Alternatively, the IC may be mounted on an FPC using the COF method or the like.

[0288] Figure 16A shows an example of a cross-section obtained by cutting a portion of the display device 100A, including the FPC 172, a portion of the circuit 164, a portion of the display unit 162, and a portion of the area including the end.

[0289] The display device 100A shown in Figure 16A has a transistor 201, a transistor 205, a light-emitting device 130a, a light-emitting device 130b, a light-emitting device 130c, and a colored layer 129a, a colored layer 129b, a colored layer 129c, etc., between a substrate 151 and a substrate 152.

[0290] Light-emitting device 130a emits red light, light-emitting device 130b emits green light, and light-emitting device 130c emits blue light. In this case, it is preferable that, for example, the colored layer 129a transmits red light, the colored layer 129b transmits green light, and the colored layer 129c transmits blue light. This makes it possible to increase the color purity of the light emitted from each light-emitting device and realize a display device with higher display quality. Note that the colored layers 129a, 129b, and 129c are not required.

[0291] Alternatively, the light-emitting devices 130a, 130b, and 130c may emit white light. The colored layers 129a, 129b, and 129c have the function of transmitting different colors from each other. The colored layers may also be called color filters.

[0292] Examples of structures capable of white light emission include single structures and tandem structures. A tandem structure for the light-emitting device is preferable because it allows for high-brightness light emission. Furthermore, by combining a structure capable of white light emission (either a single structure or a tandem structure, or both), a color filter, and an MML structure according to one aspect of the present invention, a display device with a high contrast ratio can be obtained.

[0293] Here, if the pixels of the display device have three types of subpixels having colored layers that transmit different colors from each other, examples of such three subpixels include subpixels of three colors: red (R), green (G), and blue (B); and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). If there are four such subpixels, examples of such four subpixels include subpixels of four colors: R, G, B, and white (W); and subpixels of four colors: R, G, B, and Y.

[0294] A display device according to one aspect of the present invention may be a top-emission type that emits light in the direction opposite to the substrate on which the light-emitting device is formed, a bottom-emission type that emits light toward the substrate on which the light-emitting device is formed, or a dual-emission type that emits light on both sides.

[0295] It is preferable to use EL devices such as OLED (Organic Light Emitting Diode) or QLED (Quantum-dot Light Emitting Diode) as light-emitting devices 130a, 130b, and 130c. Examples of light-emitting materials for EL devices include fluorescent materials, phosphorescent materials, inorganic compounds (such as quantum dot materials), and thermally activated delayed fluorescence (Thermally Activated Delayed Fluorescence (TADF) materials). As the TADF material, a material in which the singlet excited state and the triplet excited state are in thermal equilibrium may be used. Since such TADF materials have a shorter emission lifetime (excitation lifetime), it is possible to suppress the decrease in efficiency in the high-brightness region of the light-emitting device.

[0296] The light-emitting device has an EL layer between a pair of electrodes. In this specification, one of the pair of electrodes may be referred to as the pixel electrode and the other as the common electrode.

[0297] In a light-emitting device, one electrode functions as the anode and the other as the cathode. The following explanation uses the example where the pixel electrode functions as the anode and the common electrode functions as the cathode.

[0298] The light-emitting device 130a includes a pixel electrode 111a, a conductive layer 122a on the pixel electrode 111a, an island-shaped first layer 123a on the conductive layer 122a, an organic layer 114 on the island-shaped first layer 123a, and a common electrode 113 on the organic layer 114. In the light-emitting device 130a, the first layer 123a and the organic layer 114 can be collectively referred to as the EL layer.

[0299] The light-emitting device 130b includes a pixel electrode 111b, a conductive layer 122b on the pixel electrode 111b, an island-shaped second layer 123b on the conductive layer 122b, an organic layer 114 on the island-shaped second layer 123b, and a common electrode 113 on the organic layer 114. In the light-emitting device 130b, the second layer 123b and the organic layer 114 can be collectively referred to as the EL layer.

[0300] The light-emitting device 130c includes a pixel electrode 111c, a conductive layer 122c on the pixel electrode 111c, an island-shaped third layer 123c on the conductive layer 122c, an organic layer 114 on the island-shaped third layer 123c, and a common electrode 113 on the organic layer 114. In the light-emitting device 130c, the third layer 123c and the organic layer 114 can be collectively referred to as the EL layer.

[0301] Each color of light-emitting device shares the same film as a common electrode. This common electrode, shared by all light-emitting devices, is electrically connected to a conductive layer provided at the connection portion 204. As a result, the same potential is supplied to the common electrode of each light-emitting device.

[0302] Of the pixel electrodes and common electrodes, the electrode that extracts light should preferably use a conductive film that transmits visible light. Furthermore, it is preferable to use a conductive film that reflects visible light on the electrode that does not extract light.

[0303] As materials for forming the pair of electrodes (pixel electrode and common electrode) of a light-emitting device, metals, alloys, electrically conductive compounds, and mixtures thereof can be used as appropriate. Specifically, examples include indium tin oxide (In-Sn oxide, also called ITO), In-Si-Sn oxide (also called ITSO), indium zinc oxide (In-Zn oxide), In-W-Zn oxide, aluminum-containing alloys such as aluminum, nickel, and lanthanum alloys (Al-Ni-La), and silver, palladium, and copper alloys (Ag-Pd-Cu, also written as APC). In addition, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys containing these in appropriate combinations can also be used. Furthermore, elements belonging to Group 1 or Group 2 of the periodic table not exemplified above (e.g., lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these in appropriate combinations, graphene, etc., can also be used.

[0304] It is preferable that the light-emitting device has a microcavity structure. Therefore, it is preferable that one of the pair of electrodes in the light-emitting device has an electrode that is transparent to and reflective to visible light (a semi-transmissive / semi-reflective electrode), and the other has an electrode that is reflective to visible light (a reflective electrode). By having a microcavity structure in the light-emitting device, the light emitted from the light-emitting layer can be resonated between the two electrodes, thereby strengthening the light emitted from the light-emitting device.

[0305] The light transmittance of the transparent electrode shall be 40% or more. For example, it is preferable to use an electrode in the light-emitting device that has a transmittance of 40% or more for visible light (light with a wavelength of 400 nm or more and less than 750 nm). The visible light reflectance of the semi-transparent / semi-reflective electrode shall be 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes shall be 1 × 10⁻⁶ -2 A value of Ωcm or less is preferable.

[0306] The first layer 123a, the second layer 123b, and the third layer 123c are each provided in an island-like manner. The first layer 123a, the second layer 123b, and the third layer 123c each have an emissive layer. Preferably, the first layer 123a has an emissive layer that emits red light, the second layer 123b has an emissive layer that emits green light, and the third layer 123c has an emissive layer that emits blue light.

[0307] Alternatively, the first layer 123a, the second layer 123b, and the third layer 123c may have light-emitting layers that emit white light. Here, it is preferable that the island-shaped first layer 123a, the island-shaped second layer 123b, and the island-shaped third layer 123c are made of the same material. In other words, it is preferable that the island-shaped first layer 123a, the island-shaped second layer 123b, and the island-shaped third layer 123c are formed by patterning films deposited in the same process.

[0308] The luminescent layer is a layer containing a luminescent material. The luminescent layer may contain one or more types of luminescent materials. Suitable luminescent materials include those exhibiting colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red. Furthermore, materials emitting near-infrared light may also be used as luminescent materials.

[0309] Examples of luminescent materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0310] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0311] Examples of phosphorescent materials include organometallic complexes (especially iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton; organometallic complexes (especially iridium complexes) using phenylpyridine derivatives having electron-withdrawing groups as ligands; platinum complexes; and rare earth metal complexes.

[0312] The light-emitting layer may contain one or more types of organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). One or more of these organic compounds may be hole-transporting materials and / or electron-transporting materials. Alternatively, one or more of these organic compounds may be bipolar materials or TADF materials.

[0313] The light-emitting layer preferably comprises, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that readily forms an excitation complex. This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excitation complex to the light-emitting substance (phosphorescent material). By selecting a combination that forms an excitation complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the light-emitting substance, energy transfer becomes smoother, and light emission can be obtained efficiently. This configuration simultaneously achieves high efficiency, low-voltage operation, and a long lifespan for the light-emitting device.

[0314] The first layer 123a, the second layer 123b, and the third layer 123c may further include layers other than the light-emitting layer, such as a material with high hole injection properties, a material with high hole transport properties, a hole blocking material, a material with high electron transport properties, a material with high electron injection properties, an electron blocking material, or a bipolar material (a material with high electron transport and hole transport properties).

[0315] The light-emitting device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-emitting device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0316] For example, the first layer 123a, the second layer 123b, and the third layer 123c may each have one or more of the following: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0317] Among the EL layers, one or more of the following layers can be applied to be formed in common for each light-emitting device: a hole injection layer, a hole transport layer, a hole blocking layer (sometimes called a hole suppression layer), an electron blocking layer (sometimes called an electron suppression layer), an electron transport layer, and an electron injection layer. For example, a carrier injection layer (hole injection layer or electron injection layer) may be formed as the organic layer 114. Furthermore, all layers of the EL layer may be made differently for each color. In other words, the EL layer does not need to have layers that are formed in common for each color.

[0318] Preferably, the first layer 123a, the second layer 123b, and the third layer 123c each have an emissive layer and a carrier transport layer on the emissive layer. This suppresses exposure of the emissive layer to the outermost surface during the manufacturing process of the display device 100, thereby reducing damage to the emissive layer. This improves the reliability of the light-emitting device.

[0319] The hole injection layer is a layer that injects holes from the anode into the hole transport layer, and is a layer containing a material with high hole injection capabilities. Examples of materials with high hole injection capabilities include aromatic amine compounds and composite materials containing hole transport materials and acceptor materials (electron-accepting materials).

[0320] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light-emitting layer. The hole transport layer is a layer containing a hole-transporting material. The hole-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having a hole mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher hole transport capabilities than electron transport. Preferred hole transport materials include π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, furan derivatives, etc.) and aromatic amines (compounds having an aromatic amine skeleton), which are materials with high hole transport capabilities.

[0321] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light-emitting layer. The electron transport layer is a layer containing an electron-transporting material. The electron-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having an electron mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes. Examples of electron-transporting materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds.

[0322] Furthermore, the electron transport layer may have a multilayer structure, and may also have a hole blocking layer in contact with the light-emitting layer to block holes moving from the anode side through the light-emitting layer to the cathode side.

[0323] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer, and is a layer containing a material with high electron injection capabilities. Alkali metals, alkaline earth metals, or compounds thereof can be used as materials with high electron injection capabilities. Composite materials containing both electron transport materials and donor materials (electron-donating materials) can also be used as materials with high electron injection capabilities.

[0324] Examples of electron injection layers include lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), and calcium fluoride (CaF). x (where X is any number), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatrium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatrium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatrium (abbreviation: LiPPP), lithium oxide (LiO x Alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. Furthermore, the electron injection layer may be a multilayer structure of two or more layers. For example, this multilayer structure may consist of lithium fluoride in the first layer and ytterbium in the second layer.

[0325] Alternatively, an electron-transporting material may be used as the electron injection layer. For example, a compound having a lone pair of electrons and an electron-deficient heteroaromatic ring can be used as the electron-transporting material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), or a triazine ring can be used.

[0326] Furthermore, it is preferable that the lowest unoccupied molecular orbital (LUMO) of an organic compound containing a lone pair of electrons is between -3.6 eV and -2.3 eV. In addition, the highest occupied molecular orbital (HOMO) level and LUMO level of an organic compound can generally be estimated by methods such as cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy.

[0327] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz) can be used in organic compounds containing lone pairs of electrons. NBPhen has a higher glass transition temperature (Tg) and superior heat resistance compared to BPhen.

[0328] Furthermore, when fabricating a tandem light-emitting device, an intermediate layer is provided between the two light-emitting units. The intermediate layer has the function of injecting electrons into one of the two light-emitting units and holes into the other when a voltage is applied between the pair of electrodes.

[0329] As the intermediate layer, for example, a material applicable to the electron injection layer, such as lithium, can be suitably used. Alternatively, as the intermediate layer, a material applicable to the hole injection layer can be suitably used. Furthermore, the intermediate layer can include a layer containing a hole transport material and an acceptor material (electron-accepting material). Alternatively, the intermediate layer can include a layer containing an electron transport material and a donor material. By forming an intermediate layer having such a layer, the increase in driving voltage when light-emitting units are stacked can be suppressed.

[0330] The conductive layers 122a, 122b, and 122c function as optical adjustment layers. Note that the conductive layers 122a, 122b, and 122c may be omitted in some cases.

[0331] Each side of the pixel electrode 111a, pixel electrode 111b, pixel electrode 111c, conductive layer 122a, conductive layer 122b, conductive layer 122c, first layer 123a, second layer 123b, and third layer 123c is covered by insulating layer 125 and insulating layer 127. This prevents the organic layer 114 (or common electrode 113) from coming into contact with any side of the pixel electrode 111a, pixel electrode 111b, pixel electrode 111c, first layer 123a, second layer 123b, and third layer 123c, thereby suppressing short circuits in the light-emitting device. Insulating layer 127 corresponds to the resin layer 126 described in Embodiment 1 and other embodiments.

[0332] The insulating layer 125 can be an insulating layer having an inorganic material. For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used for the insulating layer 125. The insulating layer 125 may be a single layer or a laminated structure. Examples of oxide insulating films include silicon oxide film, aluminum oxide film, magnesium oxide film, indium gallium zinc oxide film, gallium oxide film, germanium oxide film, yttrium oxide film, zirconium oxide film, lanthanum oxide film, neodymium oxide film, hafnium oxide film, and tantalum oxide film. Examples of nitride insulating films include silicon nitride film and aluminum nitride film. Examples of oxidative nitride insulating films include silicon oxidative nitride film and aluminum oxidative nitride film. Examples of nitride oxide insulating films include silicon nitride oxide film and aluminum nitride oxide film. In particular, aluminum oxide film is preferred because it has a high selectivity ratio with the EL layer during etching and has the function of protecting the EL layer during the formation of the insulating layer 127, which will be described later. In particular, by applying inorganic insulating films such as aluminum oxide films, hafnium oxide films, and silicon oxide films formed by the ALD method to the insulating layer 125, it is possible to form an insulating layer 125 with fewer pinholes and excellent function in protecting the EL layer.

[0333] The insulating layer 125 can be formed using sputtering, CVD, PLD, ALD, or other methods. It is preferable to form the insulating layer 125 using the ALD method, which provides good coverage.

[0334] The insulating layer 127 provided on the insulating layer 125 has the function of flattening the recess in the insulating layer 125 formed between adjacent light-emitting devices. In other words, the presence of the insulating layer 127 has the effect of improving the flatness of the surface on which the common electrode 113 is formed. As the insulating layer 127, an insulating layer having an organic material can be suitably used. For example, as the insulating layer 127, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be applied. Alternatively, as the insulating layer 127, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin may be used. Furthermore, a photosensitive resin can be used as the insulating layer 127. A photoresist may be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0335] The difference between the height of the upper surface of the insulating layer 127 and the height of the upper surface of any of the first layer 123a, the second layer 123b, and the third layer 123c is preferably 0.5 times or less the thickness of the insulating layer 127, and more preferably 0.3 times or less. Alternatively, the insulating layer 127 may be provided such that the upper surface of any of the first layer 123a, the second layer 123b, and the third layer 123c is higher than the upper surface of the insulating layer 127. Alternatively, the insulating layer 127 may be provided such that the upper surface of the insulating layer 127 is higher than the upper surface of the light-emitting layer of the first layer 123a, the second layer 123b, or the third layer 123c.

[0336] An organic layer 114 is provided on the first layer 123a, the second layer 123b, the third layer 123c, the insulating layer 125, and the insulating layer 127, and a common electrode 113 is provided on the organic layer 114. In addition, a protective layer 131 is provided on each of the light-emitting devices 130a, 130b, and 130c. A protective layer 132 is provided on the protective layer 131. By providing protective layers 131 and 132, the reliability of the light-emitting devices can be improved.

[0337] The conductivity of protective layers 131 and 132 is not required. At least one of an insulating film, a semiconductor film, and a conductive film can be used as protective layers 131 and 132.

[0338] The presence of inorganic films in protective layers 131 and 132 prevents oxidation of the common electrode 113 and suppresses the intrusion of impurities (such as moisture and oxygen) into light-emitting devices 130a, 130b, and 130c, thereby suppressing degradation of the light-emitting devices and improving the reliability of the display device.

[0339] For protective layers 131 and 132, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxidative nitride insulating films include silicon oxide nitride films and aluminum oxide nitride films. Examples of nitride oxide insulating films include silicon oxide nitride films and aluminum oxide nitride films.

[0340] The protective layer 131 and the protective layer 132 each preferably have a nitride insulating film or a nitride oxide insulating film, and more preferably have a nitride insulating film.

[0341] Furthermore, the protective layers 131 and 132 may also be made of inorganic films containing In-Sn oxide (also known as ITO), In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or indium gallium zinc oxide (In-Ga-Zn oxide, also known as IGZO). The inorganic film is preferably highly resistive, and more specifically, it is preferably more resistive than the common electrode 113. The inorganic film may further contain nitrogen.

[0342] When the light emitted from a light-emitting device is extracted via protective layers 131 and 132, it is preferable that protective layers 131 and 132 have high transmittance to visible light. For example, ITO, IGZO, and aluminum oxide are preferred because they are inorganic materials with high transmittance to visible light.

[0343] For example, protective layers 131 and 132 can be a laminated structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a laminated structure of an aluminum oxide film and an IGZO film on the aluminum oxide film. By using such a laminated structure, impurities (water, oxygen, etc.) that penetrate to the EL layer can be suppressed.

[0344] Furthermore, protective layers 131 and 132 may have organic films. For example, protective layer 132 may have both an organic film and an inorganic film.

[0345] Different film deposition methods may be used for protective layer 131 and protective layer 132. Specifically, protective layer 131 may be formed using the ALD method and protective layer 132 may be formed using the sputtering method.

[0346] A colored layer (colored layer 129a, colored layer 129b, and colored layer 129c) is provided on the protective layer 131. Colored layer 129a has a region that overlaps with the light-emitting device 130a, colored layer 129b has a region that overlaps with the light-emitting device 130b, and colored layer 129c has a region that overlaps with the light-emitting device 130c. Colored layer 129a has a region that overlaps with at least the light-emitting layer of the light-emitting device 130a, colored layer 129b has a region that overlaps with at least the light-emitting layer of the light-emitting device 130b, and colored layer 129c has a region that overlaps with at least the light-emitting layer of the light-emitting device 130c.

[0347] The colored layers 129a, 129b, and 129c have the function of transmitting light of different colors from each other. For example, colored layer 129a has the function of transmitting red light, colored layer 129b has the function of transmitting green light, and colored layer 129c has the function of transmitting blue light. As a result, the display device 100 can display in full color. In addition, colored layers 129a, 129b, and 129c may also have the function of transmitting cyan, magenta, and yellow light.

[0348] The protective layer 132 and the substrate 152 are bonded together via the adhesive layer 142. For sealing the light-emitting device, a solid sealing structure or a hollow sealing structure can be applied. In Figure 16A, the space between substrate 152 and substrate 151 is filled with the adhesive layer 142, demonstrating a solid sealing structure. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), demonstrating a hollow sealing structure. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting device. Furthermore, the space may be filled with a resin different from the frame-shaped adhesive layer 142.

[0349] The pixel electrodes 111a, 111b, and 111c are each connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214.

[0350] Recesses are formed in the pixel electrodes 111a, 111b, and 111c so as to cover the openings provided in the insulating layer 214. It is preferable that layer 128 is embedded in these recesses. It is also preferable to form a conductive layer 122a on the pixel electrode 111a and layer 128, a conductive layer 122b on the pixel electrode 111b and layer 128, and a conductive layer 122c on the pixel electrode 111c and layer 128. The conductive layers 122a, 122b, and 122c can also be called pixel electrodes.

[0351] Layer 128 has the function of flattening the recesses of pixel electrodes 111a, 111b, and 111c. By providing layer 128, the unevenness of the surface on which the EL layer is formed can be reduced, and the coverage can be improved. Furthermore, by providing a conductive layer 122a electrically connected to pixel electrode 111a on pixel electrode 111a and on layer 128, a conductive layer 122b electrically connected to pixel electrode 111b on pixel electrode 111b and on layer 128, and a conductive layer 122c electrically connected to pixel electrode 111c on pixel electrode 111c and on layer 128, the regions overlapping with the recesses of pixel electrodes 111a, 111b, and 111c can also be used as light-emitting regions. This makes it possible to increase the aperture ratio of the pixels.

[0352] Layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used for layer 128 as appropriate. In particular, it is preferable that layer 128 be formed using an insulating material.

[0353] As layer 128, an insulating layer having an organic material can be suitably used. For example, acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be used as layer 128. Alternatively, a photosensitive resin can be used as layer 128. The photosensitive resin can be a positive-type material or a negative-type material.

[0354] By using a photosensitive resin, layer 128 can be fabricated using only exposure and development processes, reducing the impact on the surfaces of pixel electrodes 111a, 111b, and 111c due to dry etching or wet etching. Furthermore, by forming layer 128 using a negative-type photosensitive resin, it may be possible to form layer 128 using the same photomask (exposure mask) used to form the openings of the insulating layer 214.

[0355] The conductive layer 122a is provided on the pixel electrode 111a and on the layer 128. The conductive layer 122a has a first region in contact with the upper surface of the pixel electrode 111a and a second region in contact with the upper surface of the layer 128. Preferably, the height of the upper surface of the pixel electrode 111a in contact with the first region and the height of the upper surface of the layer 128 in contact with the second region are the same or approximately the same.

[0356] Similarly, the conductive layer 122b is provided on the pixel electrode 111b and on the layer 128. The conductive layer 122b has a first region in contact with the upper surface of the pixel electrode 111b and a second region in contact with the upper surface of the layer 128. Preferably, the height of the upper surface of the pixel electrode 111b in contact with the first region and the height of the upper surface of the layer 128 in contact with the second region are the same or approximately the same.

[0357] The conductive layer 122c is provided on the pixel electrode 111c and on the layer 128. The conductive layer 122c has a first region in contact with the upper surface of the pixel electrode 111c and a second region in contact with the upper surface of the layer 128. Preferably, the height of the upper surface of the pixel electrode 111c in contact with the first region and the height of the upper surface of the layer 128 in contact with the second region are the same or approximately the same.

[0358] The pixel electrode contains a material that reflects visible light, and the counter electrode contains a material that transmits visible light.

[0359] The display device 100A is a top-emission type. The light emitted from the light-emitting device is emitted towards the substrate 152. It is preferable to use a material with high transparency to visible light for the substrate 152.

[0360] Layer 101 includes a laminated structure from the substrate 151 to the insulating layer 214.

[0361] Both transistors 201 and 205 are formed on the substrate 151. These transistors can be manufactured using the same materials and the same process.

[0362] On the substrate 151, insulating layers 211, 213, 215, and 214 are provided in this order. A portion of insulating layer 211 functions as a gate insulating layer for each transistor. A portion of insulating layer 213 functions as a gate insulating layer for each transistor. Insulating layer 215 is provided covering the transistors. Insulating layer 214 is provided covering the transistors and functions as a planarization layer. The number of gate insulating layers and insulating layers covering the transistors are not limited and may be a single layer or two or more layers, respectively.

[0363] It is preferable to use a material that does not easily allow impurities such as water and hydrogen to diffuse into at least one layer of the insulating layer covering the transistor. This allows the insulating layer to function as a barrier layer. With such a configuration, the diffusion of impurities from the outside into the transistor can be effectively suppressed, thereby improving the reliability of the display device.

[0364] It is preferable to use inorganic insulating films for insulating layer 211, insulating layer 213, and insulating layer 215. Examples of inorganic insulating films that can be used include silicon nitride film, silicon oxide nitride film, silicon oxide film, silicon nitride oxide film, aluminum oxide film, and aluminum nitride film. Alternatively, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, and neodymium oxide film may also be used. Furthermore, two or more of the above insulating films may be laminated together.

[0365] Here, organic insulating films often have lower barrier properties against impurities compared to inorganic insulating films. Therefore, it is preferable that the organic insulating film has an opening near the edge of the display device 100A. This prevents impurities from entering through the organic insulating film from the edge of the display device 100A. Alternatively, the organic insulating film may be formed so that its edge is inward from the edge of the display device 100A, so that the organic insulating film is not exposed at the edge of the display device 100A.

[0366] An organic insulating film is preferred for the insulating layer 214, which functions as a planarization layer. Examples of materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. Alternatively, the insulating layer 214 may have a laminated structure of an organic insulating film and an inorganic insulating film. The outermost layer of the insulating layer 214 preferably functions as an etching protective film. This suppresses the formation of recesses in the insulating layer 214 during processing of the pixel electrode 111a or the conductive layer 122a. Alternatively, recesses may be provided in the insulating layer 214 during processing of the pixel electrode 111a or the conductive layer 122a.

[0367] In the region 228 shown in Figure 16A, an opening is formed in the insulating layer 214. This prevents impurities from entering the display unit 162 from the outside through the insulating layer 214, even when an organic insulating film is used for the insulating layer 214. Therefore, the reliability of the display device 100A can be improved.

[0368] Transistors 201 and 205 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as source and drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0369] The transistor structure of the display device of this embodiment is not particularly limited. For example, planar transistors, staggered transistors, inverse staggered transistors, etc., can be used. Furthermore, either a top-gate or bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below the semiconductor layer in which the channel is formed.

[0370] Transistors 201 and 205 are configured in which a semiconductor layer on which a channel is formed is sandwiched between two gates. The transistors may be driven by connecting the two gates and supplying them with the same signal. Alternatively, the threshold voltage of the transistors may be controlled by applying a potential to control the threshold voltage to one of the two gates and a potential to drive the other gate.

[0371] The crystallinity of the semiconductor material used in the semiconductor layer of the transistor is not particularly limited; amorphous semiconductors, crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors having a crystalline region in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0372] The semiconductor layer of the transistor preferably has a metal oxide (also called an oxide semiconductor). In other words, the display device of this embodiment preferably uses a transistor (hereinafter referred to as an OS transistor) that uses a metal oxide in the channel formation region.

[0373] In this specification, "metal oxide" refers to an oxide of a metal in a broad sense. Metal oxides are classified into oxide insulators, oxide conductors (including transparent oxide conductors), oxide semiconductors (also called oxide semiconductors or simply OS), etc. For example, when a metal oxide is used in the active layer of a transistor, that metal oxide may be referred to as an oxide semiconductor. In other words, when an OS transistor is described, it can be rephrased as a transistor having a metal oxide or oxide semiconductor.

[0374] The band gap of the metal oxide used in the semiconductor layer of the transistor is preferably 2 eV or more, and more preferably 2.5 eV or more. By using a metal oxide with a large band gap, the off-current of the OS transistor can be reduced.

[0375] The metal oxide preferably contains at least indium or zinc, and more preferably indium and zinc. For example, the metal oxide preferably contains indium, M (where M is one or more selected from gallium, aluminum, yttrium, tin, silicon, boron, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt), and zinc. In particular, M is preferably one or more selected from gallium, aluminum, yttrium, and tin, and gallium is more preferred. A metal oxide containing indium, M, and zinc may hereafter be referred to as In-M-Zn oxide.

[0376] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also written as IGZO) as the semiconductor layer of the transistor. Alternatively, an oxide containing indium (In), aluminum (Al), and zinc (Zn) (also written as IAZO) may be used as the semiconductor layer of the transistor. Alternatively, an oxide containing indium (In), aluminum (Al), gallium (Ga), and zinc (Zn) (IAGZO) may be used as the semiconductor layer.

[0377] When the metal oxide is an In-M-Zn oxide, it is preferable that the atomic ratio of In in the In-M-Zn oxide is equal to or greater than the atomic ratio of M. Examples of such In-M-Zn oxide atomic ratios of metal elements include compositions where In:M:Zn=1:1:1 or close to it, In:M:Zn=1:1:1.2 or close to it, In:M:Zn=2:1:3 or close to it, In:M:Zn=3:1:2 or close to it, In:M:Zn=4:2:3 or close to it, In:M:Zn=4:2:4.1 or close to it, In:M:Zn=5:1:3 or close to it, In:M:Zn=5:1:6 or close to it, In:M:Zn=5:1:7 or close to it, In:M:Zn=5:1:8 or close to it, In:M:Zn=6:1:6 or close to it, In:M:Zn=5:2:5 or close to it, and so on. Note that "close to it" compositions include a range of ±30% of the desired atomic ratio. By increasing the atomic ratio of indium in a metal oxide, the on-current or field-effect mobility of a transistor can be increased.

[0378] For example, when describing a composition with an atomic ratio of In:M:Zn = 4:2:3 or a similar ratio, it includes cases where, when In is set to 4, M is between 1 and 3, and Zn is between 2 and 4. Also, when describing a composition with an atomic ratio of In:M:Zn = 5:1:6 or a similar ratio, it includes cases where, when In is set to 5, M is greater than 0.1 and 2 or less, and Zn is between 5 and 7. Furthermore, when describing a composition with an atomic ratio of In:M:Zn = 1:1:1 or a similar ratio, it includes cases where, when In is set to 1, M is greater than 0.1 and 2 or less, and Zn is greater than 0.1 and 2 or less.

[0379] Furthermore, the atomic ratio of In in an In-M-Zn oxide may be less than the atomic ratio of M. Examples of such atomic ratios of metal elements in an In-M-Zn oxide include compositions where In:M:Zn = 1:3:2 or close to it, In:M:Zn = 1:3:3 or close to it, In:M:Zn = 1:3:4 or close to it, etc. By increasing the atomic ratio of M in the metal oxide, it is possible to increase the band gap of the In-M-Zn oxide and improve its resistance to photo-negative bias stress testing. Specifically, it is possible to reduce the change in threshold voltage or the change in shift voltage (Vsh) measured in the NBTIS (Negative Bias Temperature Illumination Stress) test of a transistor. Note that the shift voltage (Vsh) is defined as the Vg at which the tangent line at the point where the slope of the drain current (Id)-gate voltage (Vg) curve is maximum intersects the straight line where Id = 1 pA.

[0380] Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystal silicon).

[0381] Alternatively, the semiconductor layer of a transistor may have a layered material that functions as a semiconductor. A layered material is a general term for a group of materials having a layered crystalline structure. A layered crystalline structure is a structure in which layers formed by covalent or ionic bonds are stacked via weaker bonds than covalent or ionic bonds, such as van der Waals forces. Layered materials have high electrical conductivity within a unit layer, that is, high two-dimensional electrical conductivity. By using a material that functions as a semiconductor and has high two-dimensional electrical conductivity in the channel formation region, a transistor with a large on-current can be provided.

[0382] Examples of the above-mentioned layered materials include graphene, silicene, and chalcogenides. Chalcogenides are compounds containing chalcogens (elements belonging to Group 16). Examples of chalcogenides include transition metal chalcogenides and Group 13 chalcogenides. Specific examples of transition metal chalcogenides applicable as semiconductor layers in transistors include molybdenum sulfide (typically MoS2), molybdenum selenide (typically MoSe2), molybdenum tellurium (typically MoTe2), tungsten sulfide (typically WS2), tungsten selenide (typically WSe2), tungsten tellurium (typically WTe2), hafnium sulfide (typically HfS2), hafnium selenide (typically HfSe2), zirconium sulfide (typically ZrS2), and zirconium selenide (typically ZrSe2).

[0383] The transistors in circuit 164 and the transistors in display unit 162 may have the same structure or different structures. The structures of the multiple transistors in circuit 164 may all be the same or there may be two or more different structures. Similarly, the structures of the multiple transistors in display unit 162 may all be the same or there may be two or more different structures.

[0384] A connection portion 204 is provided in the region of substrate 151 where substrate 152 does not overlap. At the connection portion 204, wiring 165 is electrically connected to FPC 172 via conductive layer 166 and connection layer 242. The conductive layer 166 is shown as an example of a laminated structure consisting of a conductive film obtained by processing the same conductive film as pixel electrodes 111a, 111b, and 111c, and a conductive film obtained by processing the same conductive film as conductive layers 122a, 122b, and 122c. The conductive layer 166 is exposed on the upper surface of the connection portion 204. This allows the connection portion 204 and FPC 172 to be electrically connected via the connection layer 242.

[0385] It is preferable to provide a light-shielding layer 117 on the surface of the substrate 152 that faces the substrate 151. Alternatively, colored layers 129a, 129b, and 129c may be provided on the surface of the substrate 152 that faces the substrate 151. In Figure 16A, when the substrate 152 is viewed through the substrate 151, the colored layers 129a, 129b, and 129c are provided so as to cover a portion of the light-shielding layer 117.

[0386] Furthermore, various optical components can be placed on the outside of the substrate 152. Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (such as diffusion films), anti-reflective layers, and light-gathering films. Additionally, an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, and an impact-absorbing layer may be placed on the outside of the substrate 152.

[0387] By providing protective layers 131 and 132 that cover the light-emitting device, it is possible to suppress the ingress of impurities such as water into the light-emitting device and improve the reliability of the light-emitting device.

[0388] In the region 228 near the edge of the display device 100A, it is preferable that the insulating layer 215 and the protective layer 131 or protective layer 132 are in contact with each other through an opening in the insulating layer 214. In particular, it is preferable that the inorganic insulating films are in contact with each other. This suppresses the entry of impurities into the display unit 162 from the outside through the organic insulating film. Therefore, the reliability of the display device 100A can be improved.

[0389] Substrates 151 and 152 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, etc., respectively. The substrate on the side that extracts light from the light-emitting device should be made of a material that transmits the light. Using flexible materials for substrates 151 and 152 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used as substrate 151 or substrate 152.

[0390] Substrates 151 and 152 can be made from polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. One or both of substrates 151 and 152 may be made of glass of a thickness sufficient to provide flexibility.

[0391] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy for the substrate of the display device. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence).

[0392] For substrates with high optical isotropy, the absolute value of the retardation (phase difference) is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0393] Examples of films with high optical isotropy include triacetylcellulose (TAC, also known as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0394] Furthermore, when using a film as the substrate, the film may absorb water, potentially causing wrinkles or other shape changes in the display panel. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferable to use a film with a water absorption rate of 0.1% or less, and even more preferable to use a film with a water absorption rate of 0.01% or less.

[0395] As the adhesive layer 142, various types of curing adhesives can be used, such as UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0396] As the connecting layer 242, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), etc., can be used.

[0397] Materials that can be used for conductive layers such as the gate, source, and drain of transistors, as well as various wirings and electrodes that constitute display devices, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys mainly composed of these metals. Films containing these materials can be used as single layers or in a multilayer structure.

[0398] Furthermore, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene can be used as the light-transmitting conductive material. Alternatively, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metallic materials, can be used. Alternatively, nitrides of such metallic materials (e.g., titanium nitride) may be used. When using metallic materials or alloy materials (or their nitrides), it is preferable to make them thin enough to be light-transmitting. In addition, a laminated film of the above materials can be used as a conductive layer. For example, using a laminated film of a silver-magnesium alloy and indium tin oxide is preferable because it can enhance conductivity. These can also be used as conductive layers for various wirings and electrodes that constitute a display device, and as conductive layers (conductive layers that function as pixel electrodes or common electrodes) in light-emitting devices.

[0399] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide, and aluminum oxide.

[0400] Figures 16B and 16C show other examples of transistor configurations.

[0401] Transistors 209 and 210 each have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer 231 having a channel forming region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel forming region 231i. The insulating layer 225 is located at least between the conductive layer 223 and the channel forming region 231i. Furthermore, an insulating layer 218 covering the transistor may be provided.

[0402] In the transistor 209 shown in Figure 16B, an example is shown where the insulating layer 225 covers the top and sides of the semiconductor layer 231. The conductive layers 222a and 222b are connected to the low-resistance region 231n through openings provided in the insulating layers 225 and 215, respectively. Of the conductive layers 222a and 222b, one functions as the source and the other as the drain.

[0403] On the other hand, in the transistor 210 shown in Figure 16C, the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231, but does not overlap with the low-resistance region 231n. For example, the structure shown in Figure 16C can be fabricated by processing the insulating layer 225 using the conductive layer 223 as a mask. In Figure 16C, an insulating layer 215 is provided covering the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and conductive layer 222b are connected to the low-resistance region 231n, respectively, through openings in the insulating layer 215.

[0404] In addition, all of the transistors included in the pixel circuit for driving the light-emitting device may use transistors having silicon in the semiconductor layer in which the channel is formed (hereinafter, also referred to as Si transistors). Examples of the material used for the Si transistors include single-crystalline silicon, polycrystalline silicon, amorphous silicon, and the like. In particular, transistors having low-temperature polysilicon (LTPS (Low Temperature Poly Silicon)) in the semiconductor layer (hereinafter, also referred to as LTPS transistors) can be used. The LTPS transistors have high field-effect mobility and good frequency characteristics.

[0405] By applying Si transistors such as LTPS transistors, a circuit (for example, a source driver circuit) that needs to be driven at a high frequency can be formed on the same substrate as the display unit. Thereby, the external circuit mounted on the display device can be simplified, and the component cost and the mounting cost can be reduced.

[0406] In addition, it is preferable to use OS transistors for at least one of the transistors included in the pixel circuit. The OS transistors have extremely high field-effect mobility compared to transistors using amorphous silicon. In addition, the OS transistors have extremely small source-drain leakage current (hereinafter, also referred to as off-current) in the off state, and can hold the charge accumulated in the capacitor connected in series with the transistor for a long period of time. In addition, by applying the OS transistors, the power consumption of the display device can be reduced.

[0407] In addition, the off-current value of the OS transistor per 1 μm of channel width at room temperature is 1 aA (1×10 -18 A) or less, 1 zA (1×10 -21 A) or less, or 1 yA (1×10 -24 A) or less. Note that the off-current value of the Si transistor per 1 μm of channel width at room temperature is 1 fA (1×10 -15 A) or more and 1 pA (1×10 -12A) The following applies. Therefore, it can be said that the off-current of an OS transistor is about 10 orders of magnitude smaller than the off-current of a Si transistor.

[0408] By using LTPS transistors in some of the transistors included in the pixel circuit and OS transistors in others, a display device with low power consumption and high driving capability can be realized. Furthermore, a configuration combining LTPS transistors and OS transistors is sometimes referred to as LTPO. In a more preferable example, it is preferable to apply OS transistors to transistors that function as switches to control conduction and non-conduction between wiring, and LTPS transistors to transistors that control current.

[0409] For example, one of the transistors provided in the pixel circuit functions as a transistor for controlling the current flowing to the light-emitting device, and can be called a drive transistor. One of the source and drain of the drive transistor is electrically connected to the pixel electrode of the light-emitting device. It is preferable to use an LTPS transistor for this drive transistor. This makes it possible to increase the current flowing to the light-emitting device in the pixel circuit.

[0410] On the other hand, another transistor provided in the pixel circuit functions as a switch to control the selection and deselection of pixels, and can be called a selection transistor. The gate of the selection transistor is electrically connected to the gate line, and one of the source and drain is electrically connected to the source line (signal line). It is preferable to use an OS transistor for the selection transistor. This allows the pixel gradation to be maintained even when the frame frequency is significantly reduced (e.g., 1 fps or less), and thus power consumption can be reduced by stopping the driver when displaying still images.

[0411] Thus, one aspect of the present invention makes it possible to realize a display device that combines a high aperture ratio, high resolution, high display quality, and low power consumption.

[0412] Furthermore, one embodiment of the present invention is a display device having an OS transistor and a light-emitting device with an MML (metal maskless) structure. This configuration makes it possible to make the leakage current that can flow through the transistor and the leakage current that can flow between adjacent light-emitting devices (also called lateral leakage current or side leakage current) extremely small. With this configuration, when an image is displayed on the display device, the observer can observe one or more of the following: image sharpness, image clarity, high saturation, and high contrast ratio. Moreover, by making the leakage current that can flow through the transistor and the lateral leakage current between light-emitting devices extremely small, it is possible to achieve a display (also called true black display) with as little light leakage (so-called white floating) that may occur when displaying black as possible.

[0413] In particular, even among light-emitting devices with an MML structure, applying the SBS structure described above results in a configuration in which the layers provided between light-emitting devices (for example, an organic layer used in common between light-emitting devices, also called a common layer) are separated, making it possible to achieve a display with no side leakage or extremely low side leakage.

[0414] Furthermore, to increase the luminescence brightness of the light-emitting device included in the pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting device. To achieve this, it is necessary to increase the source-drain voltage of the drive transistor included in the pixel circuit. Compared to Si transistors, OS transistors have a higher breakdown voltage between the source and drain, so a higher voltage can be applied between the source and drain of an OS transistor. As a result, by using an OS transistor as the drive transistor in the pixel circuit, the amount of current flowing through the light-emitting device can be increased, thereby increasing the luminescence brightness of the light-emitting device.

[0415] Furthermore, when the transistor operates in the saturation region, OS transistors exhibit smaller changes in source-drain current in response to changes in gate-source voltage compared to Si transistors. Therefore, by using OS transistors as driving transistors in the pixel circuit, the current flowing between the source and drain can be precisely controlled by changes in gate-source voltage, thereby controlling the amount of current flowing to the light-emitting device. This allows for a wider range of tonal gradations in the pixel circuit.

[0416] Furthermore, in terms of the saturation characteristics of the current flowing when a transistor operates in the saturation region, OS transistors can supply a more stable current (saturation current) than Si transistors, even when the source-drain voltage gradually increases. Therefore, by using OS transistors as driving transistors, for example, a stable current can be supplied to a light-emitting device even if there are variations in the current-voltage characteristics of the light-emitting device containing EL material. In other words, when operating in the saturation region, the source-drain current remains almost unchanged even when the source-drain voltage is increased, thus stabilizing the luminescence brightness of the light-emitting device.

[0417] As described above, by using OS transistors in the drive transistors included in the pixel circuit, it is possible to achieve "suppression of black level floating," "increase in luminescence brightness," "multi-gradation," and "suppression of variations in light-emitting devices."

[0418] [Display device 100B] The display device 100B shown in Figure 17 differs from the display device 100A mainly in that it is a bottom-emission type. Parts that are the same as those of the display device 100A are omitted from the explanation. Although Figure 17 shows subpixels including the first layer 123a and subpixels including the second layer 123b, three or more types of subpixels can be provided, as in Figure 16A.

[0419] The light emitted by the light-emitting device is projected onto the substrate 151. It is preferable to use a material with high transparency to visible light for the substrate 151. On the other hand, the light transmittance of the material used for the substrate 152 is not a requirement.

[0420] Furthermore, the display device 100B includes a pixel electrode 111a, a pixel electrode 111b, and conductive layers 122a and 122b made of a material that transmits visible light, and a common electrode 113 made of a material that reflects visible light. Here, the conductive layer 166, which is obtained by processing the same conductive film as the pixel electrode 111a, a pixel electrode 111b, and conductive layers 122a and 122b, also includes a material that transmits visible light.

[0421] It is preferable to form a light-shielding layer 117 between the substrate 151 and the transistor 201, and between the substrate 151 and the transistor 205. Figure 17 shows an example in which a light-shielding layer 117 is provided on the substrate 151, an insulating layer 153 is provided on the light-shielding layer 117, and transistors 201, 205, etc. are provided on the insulating layer 153.

[0422] Furthermore, in the display device 100B, the colored layer 129a and the colored layer 129b are provided between the insulating layer 215 and the insulating layer 214. Preferably, the edges of the colored layer 129a and the colored layer 129b overlap with the light-shielding layer 117.

[0423] Here, for display devices 100A and 100B, Figures 18A to 18D show the cross-sectional structure of the region 138 including the pixel electrode 111a and layer 128 and its surroundings. The same applies to light-emitting devices 130b and 130c as described in Figures 18A to 18D.

[0424] Figures 16A and 17 show an example where the upper surface of layer 128 and the upper surface of pixel electrode 111a are roughly coincide, but the present invention is not limited to this. For example, as shown in Figure 18A, the upper surface of layer 128 may be higher than the upper surface of pixel electrode 111a. In this case, the upper surface of layer 128 has a shape that is convex towards the center and gently bulges outwards.

[0425] Furthermore, as shown in Figure 18B, the upper surface of layer 128 may be lower than the upper surface of the pixel electrode 111a. In this case, the upper surface of layer 128 has a gently concave shape that slopes downwards toward the center.

[0426] Furthermore, as shown in Figure 18C, if the upper surface of layer 128 is higher than the upper surface of the pixel electrode 111a, the upper part of layer 128 may extend beyond the recess formed in the pixel electrode 111a. In this case, a part of layer 128 may be formed to cover a portion of the generally flat area of ​​the pixel electrode 111a.

[0427] Furthermore, as shown in Figure 18D, in the structure shown in Figure 18C, a recess may be formed on a part of the upper surface of layer 128. This recess has a shape that is gently indented toward the center.

[0428] [Pixel layout] Next, we will explain the pixel layout. There are no particular limitations on the arrangement of subpixels, and various methods can be applied. Examples of subpixel arrangements include stripe arrangements, S-stripe arrangements, matrix arrangements, delta arrangements, Bayer arrangements, and pentile arrangements.

[0429] Furthermore, the top surface shape of a sub-pixel can be, for example, a triangle, a quadrilateral (including rectangles, trapezoids, etc.), a pentagon, or other polygons, or a polygon with rounded corners, an ellipse, or a circle. Here, the top surface shape of a sub-pixel corresponds to the top surface shape of the light-emitting region of the light-emitting device.

[0430] A stripe array is applied to pixel 110 shown in Figure 19A. Pixel 110 shown in Figure 19A is composed of three subpixels: subpixel 110a, subpixel 110b, and subpixel 110c. For example, as shown in Figure 20A, subpixel 110a may be a red subpixel R, subpixel 110b may be a green subpixel G, and subpixel 110c may be a blue subpixel B.

[0431] The pixel 110 shown in Figure 19B has an S-stripe array applied to it. The pixel 110 shown in Figure 19B is composed of three subpixels: subpixel 110a, subpixel 110b, and subpixel 110c. For example, as shown in Figure 20B, subpixel 110a may be a blue subpixel B, subpixel 110b may be a red subpixel R, and subpixel 110c may be a green subpixel G.

[0432] Figure 19C shows an example where the subpixels of each color are arranged in a zigzag pattern. Specifically, in a top view, the upper edges of two subpixels arranged in the column direction (for example, subpixels 110a and 110b, or subpixels 110b and 110c) are offset. For example, as shown in Figure 20C, subpixel 110a may be the red subpixel R, subpixel 110b may be the green subpixel G, and subpixel 110c may be the blue subpixel B.

[0433] The pixel 110 shown in Figure 19D includes a sub-pixel 110a with a roughly trapezoidal top surface shape with rounded corners, a sub-pixel 110b with a roughly triangular top surface shape with rounded corners, and a sub-pixel 110c with a roughly quadrilateral or hexagonal top surface shape with rounded corners. Furthermore, sub-pixel 110a has a larger light-emitting area than sub-pixel 110b. Thus, the shape and size of each sub-pixel can be determined independently. For example, the size of a sub-pixel can be reduced to a level that provides a more reliable light-emitting device. For example, as shown in Figure 20D, sub-pixel 110a may be a green sub-pixel G, sub-pixel 110b may be a red sub-pixel R, and sub-pixel 110c may be a blue sub-pixel B.

[0434] In photolithography, the finer the pattern being processed, the more significant the effects of light diffraction become. This compromises the fidelity of the transfer of the photomask pattern through exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, patterns with rounded corners are likely to be formed. Consequently, the top surface shape of subpixels may be a polygon with rounded corners, an ellipse, or a circle.

[0435] Furthermore, in a method for manufacturing a display device according to one aspect of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the EL layer material and the curing temperature of the resist material, the curing of the resist film may be insufficient. A resist film that is not sufficiently cured may take a shape that deviates from the desired shape during processing. As a result, the top surface shape of the EL layer may become a polygon with rounded corners, an ellipse, or a circle. For example, if an attempt is made to form a resist mask with a square top surface, a resist mask with a circular top surface may be formed, resulting in a circular top surface shape for the EL layer.

[0436] Furthermore, in order to achieve the desired shape of the upper surface of the EL layer, a technique (OPC (Optical Proximity Correction) technique) may be used to pre-correct the mask pattern so that the design pattern and the transferred pattern match. Specifically, in the OPC technique, a correction pattern is added to the corners of the shape on the mask pattern.

[0437] The pixels 110 shown in Figures 21A to 21C have a stripe arrangement applied to them.

[0438] Figure 21A shows an example where each subpixel has a rectangular top surface shape, Figure 21B shows an example where each subpixel has a top surface shape formed by connecting two semicircles and a rectangle (also called an oval shape), and Figure 21C shows an example where each subpixel has an elliptical top surface shape.

[0439] The pixel 110 shown in Figures 21A to 21C is composed of four subpixels: subpixel 110a, subpixel 110b, subpixel 110c, and subpixel 110d. Each of the subpixels 110a, 110b, 110c, and 110d emits light of a different color. For example, subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and white subpixels, respectively. For example, as shown in Figure 22A, subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and white subpixels, respectively. Alternatively, subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and infrared emitting subpixels, respectively.

[0440] The sub-pixel 110d has a light-emitting device. The light-emitting device has a pixel electrode, an island-shaped fourth layer of the pixel electrode, an organic layer 114 on the island-shaped fourth layer, and a common electrode 113 on the organic layer 114. In this light-emitting device, the fourth layer and the organic layer 114 can be collectively called the EL layer. The pixel electrode may be made of the same material as the pixel electrode 111a, pixel electrode 111b, and pixel electrode 111c. The fourth layer may be made of the same material as the first layer 123a, the second layer 123b, and the third layer 123c.

[0441] Figure 21D shows an example where one pixel 110 is composed of two rows and three columns. Pixel 110 has three subpixels (subpixels 110a, 110b, and 110c) in the top row (1st row) and three subpixels 110d in the bottom row (2nd row). In other words, pixel 110 has subpixels 110a and 110d in the left column (1st column), subpixels 110b and 110d in the middle column (2nd column), and subpixels 110c and 110d in the right column (3rd column). As shown in Figure 21D, by aligning the arrangement of subpixels in the top row and the bottom row, it becomes possible to efficiently remove dust and other debris that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided.

[0442] Figure 21E shows an example where a single pixel 110 is composed of 2 rows and 3 columns. Pixel 110 has three subpixels (subpixels 110a, 110b, and 110c) in the top row (row 1) and one subpixel (subpixel 110d) in the bottom row (row 2). In other words, pixel 110 has subpixel 110a in the left column (column 1), subpixel 110b in the middle column (column 2), subpixel 110c in the right column (column 3), and subpixel 110d across these three columns.

[0443] Furthermore, in the pixel 110 shown in Figures 21D and 21E, for example, as shown in Figures 22B and 22C, sub-pixel 110a can be a red sub-pixel R, sub-pixel 110b can be a green sub-pixel G, sub-pixel 110c can be a blue sub-pixel B, and sub-pixel 110d can be a white sub-pixel W.

[0444] A display device according to one aspect of the present invention may have a light-receiving device (also called a light-receiving element) in each pixel.

[0445] Of the four subpixels of pixel 110 shown in Figure 21D or Figure 21E, three may be configured to have light-emitting devices, and the remaining one may be configured to have a light-receiving device.

[0446] For example, a pn-type or pin-type photodiode can be used as the light-receiving device. The light-receiving device functions as a photoelectric conversion device (also called a photoelectric conversion element) that detects light incident on it and generates an electric charge. The amount of charge generated from the light-receiving device is determined by the amount of light incident on it.

[0447] In particular, it is preferable to use an organic photodiode having a layer containing an organic compound as the light-receiving device. Organic photodiodes can be easily made thinner, lighter, and larger in area, and because they offer a high degree of freedom in shape and design, they can be applied to various display devices.

[0448] In one aspect of the present invention, an organic EL device is used as the light-emitting device, and an organic photodiode is used as the light-receiving device. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be incorporated into a display device using an organic EL device.

[0449] The light-receiving device has at least an active layer functioning as a photoelectric conversion layer between a pair of electrodes. In this specification, one of the pair of electrodes may be referred to as the pixel electrode and the other as the common electrode.

[0450] For example, sub-pixels 110a, 110b, and 110c may be sub-pixels of three colors, R, G, and B, and sub-pixel 110d may be a sub-pixel having a light-receiving device. In this case, the fourth layer has at least an active layer.

[0451] In a photodetector, one electrode functions as the anode and the other as the cathode. The following explanation uses the example where the pixel electrode functions as the anode and the common electrode functions as the cathode. The photodetector can detect incoming light, generate an electric charge, and extract it as an electric current by applying a reverse bias between the pixel electrode and the common electrode. Alternatively, the pixel electrode may function as the cathode and the common electrode as the anode.

[0452] The same manufacturing methods as for light-emitting devices can be applied to light-receiving devices. The island-shaped active layer (also called the photoelectric conversion layer) of the light-receiving device is not formed by the pattern of the metal mask, but rather by processing after depositing the film that will become the active layer onto the entire surface, so that the island-shaped active layer can be formed with a uniform thickness. In addition, by providing a sacrificial layer on the active layer, the damage that the active layer receives during the manufacturing process of the display device can be reduced, and the reliability of the light-receiving device can be improved.

[0453] Here, layers common to both the light-receiving and light-emitting devices may have different functions in the light-emitting device and the light-receiving device. In this specification, components may be referred to based on their function in the light-emitting device. For example, a hole injection layer functions as a hole injection layer in the light-emitting device and as a hole transport layer in the light-receiving device. Similarly, an electron injection layer functions as an electron injection layer in the light-emitting device and as an electron transport layer in the light-receiving device. Furthermore, layers common to both the light-receiving and light-emitting devices may have the same function in the light-emitting device and the light-receiving device. For example, a hole transport layer functions as a hole transport layer in both the light-emitting and light-receiving devices, and an electron transport layer functions as an electron transport layer in both the light-emitting and light-receiving devices.

[0454] The active layer of a light-receiving device includes a semiconductor. Examples of such semiconductors include inorganic semiconductors such as silicon, and organic semiconductors containing organic compounds. In this embodiment, an example is shown in which an organic semiconductor is used as the semiconductor of the active layer. Using an organic semiconductor is preferable because the light-emitting layer and the active layer can be formed using the same method (for example, vacuum deposition), and the manufacturing equipment can be shared.

[0455] As for the n-type semiconductor material of the active layer, fullerene (for example, C 60 , C 70 Examples include electron-accepting organic semiconductor materials such as fullerene derivatives. Fullerenes have a shape like a soccer ball, and this shape is energetically stable. Both the HOMO and LUMO levels of fullerenes are deep (low). Because the LUMO level of fullerenes is deep, they have extremely high electron-accepting properties. Normally, when π-electron conjugation (resonance) spreads out in a plane, as in benzene, electron-donating properties increase, but because fullerenes have a spherical shape, they have high electron-accepting properties despite the large spread of π-electron conjugation. High electron-accepting properties allow for fast and efficient charge separation, making them useful as photodetectors. 60 , C 70Both have a broad absorption band in the visible light region, and especially C 70 is C 60 Compared to [another compound], it is preferable because it has a larger π-electron conjugation system and a broad absorption band in the long-wavelength region. Other examples of fullerene derivatives include [6,6]-Phenyl-C71-butyric acid methyl ester (abbreviated as PC70BM), [6,6]-Phenyl-C61-butyric acid methyl ester (abbreviated as PC60BM), and 1',1'',4',4''-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2'',3''][5,6]fullerene-C60 (abbreviated as ICBA).

[0456] Furthermore, examples of n-type semiconductor materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, naphthalene derivatives, anthracene derivatives, coumarin derivatives, rhodamine derivatives, triazine derivatives, and quinone derivatives.

[0457] Examples of p-type semiconductor materials for the active layer include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin phthalocyanine (SnPc), and quinacridone.

[0458] Furthermore, examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, and compounds having an aromatic amine skeleton. In addition, examples of p-type semiconductor materials include naphthalene derivatives, anthracene derivatives, pyrene derivatives, triphenylene derivatives, fluorene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, indrocarbazole derivatives, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, quinacridone derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polythiophene derivatives.

[0459] The HOMO level of electron-donating organic semiconductor materials is preferably shallower (higher) than the HOMO level of electron-accepting organic semiconductor materials. The LUMO level of electron-donating organic semiconductor materials is preferably shallower (higher) than the LUMO level of electron-accepting organic semiconductor materials.

[0460] It is preferable to use spherical fullerenes as electron-accepting organic semiconductor materials and organic semiconductor materials with a near-planar shape as electron-donating organic semiconductor materials. Molecules with similar shapes tend to aggregate, and when molecules of the same type aggregate, their molecular orbital energy levels are close, which can improve carrier transport.

[0461] For example, the active layer is preferably formed by co-depositing an n-type semiconductor and a p-type semiconductor. Alternatively, the active layer may be formed by stacking an n-type semiconductor and a p-type semiconductor.

[0462] The photodetector may further include layers other than the active layer, such as a material with high hole transport properties, a material with high electron transport properties, or a bipolar material (a material with high electron and hole transport properties). Furthermore, it may also further include layers containing a material with high hole injection properties, a hole blocking material, a material with high electron injection properties, an electron blocking material, etc.

[0463] The light-receiving device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-receiving device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0464] For example, polymer compounds such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) and inorganic compounds such as molybdenum oxide and copper iodide (CuI) can be used as hole transporting materials or electron blocking materials. In addition, inorganic compounds such as zinc oxide (ZnO) and organic compounds such as polyethyleneimine ethoxylate (PEIE) can be used as electron transporting materials or hole blocking materials. The light-receiving device may have, for example, a mixed film of PEIE and ZnO.

[0465] Furthermore, the active layer can use polymer compounds such as Poly[[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c']dithiophene-1,3-diyl]]polymer (abbreviated as PBDB-T) or PBDB-T derivatives, which function as donors. For example, a method of dispersing the acceptor material in PBDB-T or a PBDB-T derivative can be used.

[0466] Furthermore, the active layer may contain a mixture of three or more materials. For example, to broaden the wavelength range, a third material may be mixed with an n-type semiconductor material and a p-type semiconductor material. In this case, the third material may be a low-molecular-weight compound or a high-molecular-weight compound.

[0467] In a display device having light-emitting and light-receiving devices in its pixels, the pixels have a light-receiving function, allowing for the detection of contact or proximity of an object while displaying an image. For example, not only can the display device display an image using all of its subpixels, but some subpixels can also emit light as a light source, while the remaining subpixels display an image.

[0468] A display device according to one aspect of the present invention has a display unit in which light-emitting devices are arranged in a matrix, and an image can be displayed on the display unit. Furthermore, light-receiving devices are arranged in a matrix on the display unit, and the display unit has an image display function, as well as one or both of an imaging function and a sensing function. The display unit can be used as an image sensor or a touch sensor. That is, by detecting light on the display unit, an image can be captured, or the proximity or contact of an object (such as a finger, hand, or pen) can be detected. Moreover, in a display device according to one aspect of the present invention, the light-emitting devices can be used as a light source for a sensor. Therefore, it is not necessary to provide a separate light-receiving unit and light source from the display device, and the number of components in the electronic device can be reduced.

[0469] In one embodiment of the present invention, when an object reflects (or scatters) light emitted by a light-emitting device of the display unit, a light-receiving device can detect the reflected light (or scattered light), thus enabling image capture or touch detection even in dark places.

[0470] When a light-receiving device is used as an image sensor, the display device can capture an image using the light-receiving device. For example, the display device of this embodiment can be used as a scanner.

[0471] For example, an image sensor can be used to acquire biometric data such as fingerprints and palm prints. In other words, a biometric authentication sensor can be built into the display device. By having the display device incorporate the biometric authentication sensor, the number of components in the electronic device can be reduced compared to when a separate biometric authentication sensor is provided, enabling miniaturization and weight reduction of the electronic device.

[0472] Furthermore, when a light-receiving device is used as a touch sensor, the display device can use the light-receiving device to detect the proximity or contact of an object.

[0473] The pixels shown in Figures 23A to 23C have sub-pixels G, B, R, and PS.

[0474] The pixels shown in Figure 23A have a stripe array applied to them.

[0475] Figures 23B and 23C show an example where one pixel is arranged across two rows and three columns. The top row (first row) has three subpixels (subpixel G, subpixel B, and subpixel R). In Figure 23B, the bottom row (second row) has three subpixels PS. On the other hand, in Figure 23C, the bottom row (second row) has two subpixels PS. As shown in Figure 23B, by aligning the arrangement of subpixels in the top and bottom rows, it becomes possible to efficiently remove dust and other debris that may occur during the manufacturing process. Therefore, a display device with high display quality can be provided. Note that the layout of subpixels is not limited to the configuration shown in Figures 23A to 23C.

[0476] Sub-pixel R has a light-emitting device that emits red light, sub-pixel G has a light-emitting device that emits green light, and sub-pixel B has a light-emitting device that emits blue light. Alternatively, sub-pixels R, G, and B each have a light-emitting device that emits white light. If sub-pixels R, G, and B each have a light-emitting device that emits white light, a corresponding colored layer is provided superimposed on the light-emitting device in sub-pixels R, G, and B.

[0477] The sub-pixel PS has a light-receiving device. The wavelength of light detected by the sub-pixel PS is not particularly limited.

[0478] The light-receiving device in the sub-pixel PS preferably detects visible light, and more preferably detects one or more colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red. Alternatively, the light-receiving device in the sub-pixel PS may also detect infrared light.

[0479] The configuration shown in Figure 23A and other figures includes a light-emitting device and a light-receiving device in each pixel. In one embodiment of the present invention, since the pixels have a light-receiving function, it is possible to detect contact or proximity of an object while displaying an image. Furthermore, since one embodiment of the present invention has sub-pixels that emit infrared light, it is also possible to display an image while emitting infrared light as a light source using the sub-pixels of the display device. In other words, one embodiment of the present invention has a configuration that is highly compatible with functions other than display functions (in this case, light-receiving functions).

[0480] Furthermore, the light-receiving devices of the pixels shown in Figure 23A and other figures may be used as touch sensors or non-contact sensors.

[0481] Here, a touch sensor or a non-contact sensor can detect the proximity or contact of an object (such as a finger, hand, or pen). A touch sensor can detect an object when the electronic device and the object are in direct contact. A non-contact sensor can detect an object even if the object does not come into contact with the electronic device. For example, it is preferable that the display device (or electronic device) can detect an object when the distance between the display device (or electronic device) and the object is in the range of 0.1 mm to 300 mm, preferably 3 mm to 50 mm. With this configuration, it becomes possible to operate the electronic device without the object directly touching it; in other words, it becomes possible to operate the display device without contact (touchless). With the above configuration, the risk of the electronic device becoming dirty or scratched can be reduced, or it becomes possible to operate the electronic device without the object directly touching any dirt (e.g., dust or viruses) attached to the electronic device.

[0482] Furthermore, non-contact sensor functions can also be referred to as hover sensor functions, hover-touch sensor functions, near-touch sensor functions, touchless sensor functions, etc. Similarly, touch sensor functions can also be referred to as direct-touch sensor functions, etc.

[0483] Furthermore, a display device according to one aspect of the present invention can have a variable refresh rate. For example, power consumption can be reduced by adjusting the refresh rate according to the content displayed on the display device (for example, within a range of 0.01 Hz to 240 Hz). In addition, a drive that reduces the power consumption of the display device by driving with a reduced refresh rate may be called an idling stop (IDS) drive.

[0484] Furthermore, the drive frequency of the touch sensor or near-touch sensor may be changed according to the refresh rate mentioned above. For example, if the refresh rate of the display device is 120Hz, the drive frequency of the touch sensor or near-touch sensor can be set to a frequency higher than 120Hz (typically 240Hz). This configuration enables low power consumption and increases the response speed of the touch sensor or near-touch sensor.

[0485] This embodiment can be combined with other embodiments as appropriate.

[0486] (Embodiment 4) The display device described in the previous embodiment may also have a light-receiving element. In this embodiment, a display device (also called a light-emitting / receiving device) having a light-emitting element and a light-receiving element will be described.

[0487] The light-receiving and light-emitting unit of one embodiment of the present invention has a light-receiving element (also called a light-receiving device) and a light-emitting element (also called a light-emitting device). The light-receiving and light-emitting unit has the function of displaying an image using the light-emitting element. Furthermore, the light-receiving and light-emitting unit has one or both of the functions of capturing images and sensing using the light-receiving element. Therefore, the light-receiving and light-emitting unit of one embodiment of the present invention can also be described as a display device, and the light-receiving and light-emitting unit can also be described as a display unit.

[0488] Alternatively, a light-receiving and light-emitting device according to one aspect of the present invention may have a configuration comprising a light-receiving and light-emitting element (also called a light-receiving and light-emitting device) and a light-emitting element.

[0489] First, we will describe a light-receiving and light-emitting device having a light-receiving element and a light-emitting element.

[0490] One embodiment of the present invention provides a light-receiving and light-emitting device having a light-receiving element and a light-emitting element in its light-receiving and light-emitting section. In one embodiment of the present invention, the light-emitting elements are arranged in a matrix in the light-receiving and light-emitting device, and the light-receiving and light-emitting device can display an image. Furthermore, the light-receiving and light-emitting device also has light-receiving elements arranged in a matrix, and the light-receiving and light-emitting device has either an imaging function or a sensing function, or both. The light-receiving and light-emitting device can be used as an image sensor, a touch sensor, etc. That is, by detecting light in the light-receiving and light-emitting device, it is possible to capture an image or detect touch operations of an object (finger, pen, etc.). Moreover, in one embodiment of the present invention, the light-emitting elements can be used as a light source for a sensor. Therefore, it is not necessary to provide a separate light-receiving section and light source from the light-receiving and light-emitting device, and the number of components in the electronic device can be reduced.

[0491] In one embodiment of the present invention, when an object reflects (or scatters) the light emitted by the light-emitting element of the light-emitting unit, the light-receiving element can detect the reflected (or scattered) light, making it possible to perform tasks such as image capture and touch operation detection even in dark places.

[0492] A light-emitting element in a light-receiving device according to one aspect of the present invention functions as a display element (also called a display device).

[0493] As the light-emitting element, it is preferable to use an EL element (also called an EL device) such as an OLED or QLED. Examples of light-emitting materials for EL elements include fluorescent materials, phosphorescent materials, inorganic compounds (such as quantum dot materials), and thermally activated delayed fluorescence (TADF) materials. In addition, LEDs such as microLEDs can also be used as the light-emitting element.

[0494] A light-receiving and light-emitting device according to one aspect of the present invention has the function of detecting light using a light-receiving element.

[0495] When a light-receiving element is used as an image sensor, the light-receiving and light-emitting device can capture an image using the light-receiving element. For example, the light-receiving and light-emitting device can be used as a scanner.

[0496] An electronic device to which a light-receiving device according to one aspect of the present invention is applied can acquire data related to biometric information such as fingerprints and palm prints using its function as an image sensor. In other words, a biometric authentication sensor can be built into the light-receiving device. By building a biometric authentication sensor into the light-receiving device, the number of components in the electronic device can be reduced compared to a case where a separate biometric authentication sensor is provided in the light-receiving device, enabling miniaturization and weight reduction of the electronic device.

[0497] Furthermore, when a light-receiving element is used in a touch sensor, the light-receiving device can use the light-receiving element to detect touch operations on the object.

[0498] For details regarding the configuration of the light-receiving element, etc., please refer to the description of the configuration of the light-receiving device, etc., described in Embodiment 3.

[0499] In one aspect of the present invention, an organic EL element (also called an organic EL device) is used as a light-emitting element, and an organic photodiode is used as a light-receiving element. The organic EL element and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be incorporated into a display device using an organic EL element.

[0500] If all the layers constituting an organic EL element and an organic photodiode were to be fabricated separately, the number of film deposition steps would become enormous. However, since organic photodiodes have many layers that can share the same configuration as organic EL elements, the increase in film deposition steps can be suppressed by depositing these common layers in a single process.

[0501] For example, one of a pair of electrodes (the common electrode) can be a common layer for both the photodetector and the light-emitting element. Alternatively, at least one of the hole injection layer, hole transport layer, electron transport layer, and electron injection layer may be a common layer for both the photodetector and the light-emitting element. By having a common layer for both the photodetector and the light-emitting element in this way, the number of film deposition cycles and masks can be reduced, thereby reducing the manufacturing process and cost of the light-receiving device. Furthermore, a light-receiving device with a photodetector can be manufactured using existing manufacturing equipment and methods for display devices.

[0502] Next, we will describe a light-emitting / receiving device having a light-emitting / receiving element. Note that explanations of functions, operations, and effects similar to those described above may be omitted.

[0503] In one embodiment of the present invention, a sub-pixel exhibiting one of the colors has a light-receiving element instead of a light-emitting element, while a sub-pixel exhibiting another color has a light-emitting element. The light-receiving element has both a function of emitting light (light emission function) and a function of receiving light (light receiving function). For example, if a pixel has three sub-pixels, a red sub-pixel, a green sub-pixel, and a blue sub-pixel, at least one sub-pixel has a light-receiving element, and the other sub-pixels have light-emitting elements. Therefore, the light-receiving unit of one embodiment of the present invention has the function of displaying an image using both a light-receiving element and a light-emitting element.

[0504] By having the light-emitting element serve as both the light-emitting element and the light-receiving element, it is possible to add a light-receiving function to a pixel without increasing the number of subpixels included in the pixel. This makes it possible to add either or both imaging and sensing functions to the light-emitting section of the light-emitting device while maintaining the aperture ratio of the pixel (aperture ratio of each subpixel) and the resolution of the light-emitting device. Therefore, in one embodiment of the present invention, the aperture ratio of the pixel can be increased and high resolution can be easily achieved compared to a case where subpixels having light-receiving elements are provided separately from subpixels having light-emitting elements.

[0505] In one embodiment of the present invention, a light-receiving and light-emitting device has a light-receiving and light-emitting element arranged in a matrix in the light-receiving and light-emitting section, and can display an image in the light-receiving and light-emitting section. The light-receiving and light-emitting section can also be used as an image sensor, a touch sensor, etc. In one embodiment of the present invention, the light-emitting element can be used as a light source for the sensor. Therefore, imaging and detection of touch operations are possible even in dark places.

[0506] Light-emitting and receiving devices can be fabricated by combining organic EL elements and organic photodiodes. For example, a light-emitting and receiving device can be fabricated by adding an active layer of an organic photodiode to the stacked structure of an organic EL element. Furthermore, when fabricating a light-emitting and receiving device by combining an organic EL element and an organic photodiode, the number of film deposition steps can be increased by depositing layers that can share a common structure with the organic EL element in a single process.

[0507] For example, one of a pair of electrodes (the common electrode) can be a layer common to both the light-receiving and light-emitting elements. Alternatively, at least one of the hole injection layer, hole transport layer, electron transport layer, and electron injection layer may be a layer common to both the light-receiving and light-emitting elements.

[0508] Furthermore, the function of the layers in a light-receiving element may differ depending on whether the element functions as a light-receiving element or as a light-emitting element. In this specification, the components are referred to based on their function when the element functions as a light-emitting element.

[0509] The light-emitting and light-receiving device of this embodiment has the function of displaying an image using a light-emitting element and a light-receiving element. In other words, the light-emitting element and the light-receiving element function as display elements.

[0510] The light-receiving and light-emitting device of this embodiment has the function of detecting light using a light-receiving and light-emitting element. The light-receiving and light-emitting element can detect light with a shorter wavelength than the light it emits itself.

[0511] When the light-emitting / receiving element is used as an image sensor, the light-emitting / receiving device of this embodiment can capture an image using the light-emitting / receiving element. Furthermore, when the light-emitting / receiving element is used as a touch sensor, the light-emitting / receiving device of this embodiment can detect touch operations on an object using the light-emitting / receiving element.

[0512] The light-receiving element functions as a photoelectric conversion element. The light-receiving element can be fabricated by adding an active layer of a light-receiving element to the configuration of the light-receiving element described above. For example, the active layer of a pn-type or pin-type photodiode can be used for the light-receiving element.

[0513] In particular, it is preferable to use an organic photodiode with an active layer containing an organic compound as the light-emitting and receiving element. Organic photodiodes can be easily made thinner, lighter, and larger in area, and because they offer a high degree of freedom in shape and design, they can be applied to a variety of devices.

[0514] In the following section, a display device, which is an example of a light-receiving and light-emitting device according to one aspect of the present invention, will be described in more detail with reference to the drawings.

[0515] [Example of a display device configuration] [Configuration Example 1] Figure 24A shows a schematic diagram of the display panel 300. The display panel 300 includes a substrate 301, a substrate 302, a light-receiving element 312, a light-emitting element 311R, a light-emitting element 311G, a light-emitting element 311B, a functional layer 303, and the like.

[0516] The light-emitting element 311R, light-emitting element 311G, light-emitting element 311B, and light-receiving element 312 are provided between substrate 301 and substrate 302. The light-emitting elements 311R, 311G, and 311B emit red (R), green (G), and blue (B) light, respectively. In the following, when light-emitting elements 311R, 311G, and 311B are not distinguished, they may be referred to simply as light-emitting element 311.

[0517] The display panel 300 has a plurality of pixels arranged in a matrix. Each pixel has one or more subpixels. Each subpixel has one light-emitting element. For example, a pixel can have a configuration with three subpixels (three colors: R, G, and B, or three colors: yellow (Y), cyan (C), and magenta (M)), or a configuration with four subpixels (four colors: R, G, B, and white (W), or four colors: R, G, B, and Y). Furthermore, each pixel has a light-receiving element 312. The light-receiving element 312 may be provided in all pixels or in some pixels. Also, a single pixel may have multiple light-receiving elements 312.

[0518] Figure 24A shows how a finger 320 touches the surface of the substrate 302. A portion of the light emitted by the light-emitting element 311G is reflected at the contact point between the substrate 302 and the finger 320. A portion of the reflected light is then incident on the light-receiving element 312, allowing detection that the finger 320 has touched the substrate 302. In other words, the display panel 300 can function as a touch panel.

[0519] The functional layer 303 includes circuits for driving the light-emitting elements 311R, 311G, and 311B, and a circuit for driving the light-receiving element 312. The functional layer 303 is provided with switches, transistors, capacitors, wiring, etc. However, when the light-emitting elements 311R, 311G, 311B, and the light-receiving element 312 are driven in a passive matrix manner, the configuration may be made without switches, transistors, etc.

[0520] Preferably, the display panel 300 has a function to detect the fingerprint of the finger 320. Figure 24B schematically shows an enlarged view of the contact area when the finger 320 is in contact with the substrate 302. Figure 24B also shows alternately arranged light-emitting elements 311 and light-receiving elements 312.

[0521] Fingerprints are formed on finger 320 by recesses and protrusions. Therefore, as shown in Figure 24B, the protrusions of the fingerprints are in contact with the substrate 302.

[0522] Light reflected from a surface or interface can be either specular or diffuse. Specularly reflected light is highly directional, with the angle of incidence and the angle of reflection being the same, while diffusely reflected light is less directional, with low angular dependence of intensity. The light reflected from the surface of finger 320 is predominantly diffuse. On the other hand, the light reflected from the interface between substrate 302 and the atmosphere is predominantly specular.

[0523] The intensity of light reflected from the contact or non-contact surface between the finger 320 and the substrate 302, and incident on the photodetector 312 located directly beneath them, is the sum of specular reflection and diffuse reflection. As described above, in the recessed areas of the finger 320, the substrate 302 and the finger 320 do not come into contact, so specular reflection (indicated by the solid arrow) is dominant, while in the convex areas, they come into contact, so diffuse reflection from the finger 320 (indicated by the dashed arrow) is dominant. Therefore, the intensity of light received by the photodetector 312 located directly beneath the recessed areas is higher than that received by the photodetector 312 located directly beneath the convex areas. This allows for imaging of the fingerprint of the finger 320.

[0524] The spacing between the light-receiving elements 312 is set to be smaller than the distance between two protrusions of a fingerprint, preferably the distance between an adjacent recess and a protrusion, thereby enabling the acquisition of a clear fingerprint image. Since the distance between a recess and a protrusion in a human fingerprint is approximately 200 μm, for example, the spacing between the light-receiving elements 312 is 400 μm or less, preferably 200 μm or less, more preferably 150 μm or less, even more preferably 100 μm or less, and even more preferably 50 μm or less, and 1 μm or more, preferably 10 μm or more, and more preferably 20 μm or more.

[0525] Figure 24C shows an example of a fingerprint image captured by the display panel 300. In Figure 24C, the outline of the finger 320 is shown with a dashed line and the outline of the contact area 321 is shown with a dashed line within the imaging range 323. Within the contact area 321, a high-contrast fingerprint 322 can be captured due to the difference in the amount of light incident on the light-receiving element 312.

[0526] The display panel 300 can also function as a touch panel and a pen tablet. Figure 24D shows the tip of the stylus 325 in contact with the substrate 302 and being slid in the direction of the dashed arrow.

[0527] As shown in Figure 24D, diffusely reflected light diffused at the contact surface between the tip of the stylus 325 and the substrate 302 is incident on the light-receiving element 312 located in the area overlapping with the contact surface, thereby enabling high-precision detection of the position of the tip of the stylus 325.

[0528] Figure 24E shows an example of the trajectory 326 of the stylus 325 detected by the display panel 300. Because the display panel 300 can detect the position of the object being detected, such as the stylus 325, with high positional accuracy, it is possible to perform high-resolution drawing in drawing applications, etc. Furthermore, unlike when using capacitive touch sensors or electromagnetic induction type touch pens, it is possible to detect the position of the object being detected even if it has high insulating properties, so the material of the tip of the stylus 325 is not a concern, and various writing instruments (e.g., brushes, glass pens, quill pens, etc.) can be used.

[0529] Here, Figures 24F and 24G show examples of pixels applicable to the display panel 300.

[0530] The pixels shown in Figure 24F each have a red (R) light-emitting element 311R, a green (G) light-emitting element 311G, a blue (B) light-emitting element 311B, and a light-receiving element 312. Each pixel has a pixel circuit for driving the light-emitting elements 311R, 311G, 311B, and the light-receiving element 312.

[0531] Figure 24F shows an example in which three light-emitting elements are arranged in a row, with a single horizontally elongated light-receiving element 312 positioned below them.

[0532] The pixel shown in Figure 24G is an example having a white (W) light-emitting element 311W. Here, four light-emitting elements are arranged in a row, with a light-receiving element 312 positioned below them.

[0533] Furthermore, the pixel configuration is not limited to the above, and various arrangement methods can be adopted.

[0534] [Configuration Example 2] The following describes an example of a configuration comprising a light-emitting element that emits visible light, a light-emitting element that emits infrared light, and a light-receiving element.

[0535] The display panel 300A shown in Figure 25A has a light-emitting element 311IR in addition to the configuration illustrated in Figure 24A. The light-emitting element 311IR is a light-emitting element that emits infrared light (IR). In this case, it is preferable to use a light-receiving element 312 that can receive at least the infrared light (IR) emitted by the light-emitting element 311IR. It is even more preferable to use a light-receiving element 312 that can receive both visible light and infrared light.

[0536] As shown in Figure 25A, when the finger 320 touches the substrate 302, the infrared light IR emitted from the light-emitting element 311IR is reflected by the finger 320, and a portion of this reflected light is incident on the light-receiving element 312, thereby allowing the position information of the finger 320 to be obtained.

[0537] Figures 25B and 25C show examples of pixels applicable to the display panel 300A.

[0538] Figure 25B shows an example where three light-emitting elements are arranged in a row, with the light-emitting element 311IR and the light-receiving element 312 positioned side by side below them. Figure 25C shows an example where four light-emitting elements, including the light-emitting element 311IR, are arranged in a row, with the light-receiving element 312 positioned below them.

[0539] In addition, in the pixels shown in Figures 25B and 25C, the positions of the light-emitting elements and the light-emitting elements and the light-receiving elements are interchangeable.

[0540] [Configuration Example 3] The following describes an example of a configuration comprising a light-emitting element that emits visible light and a light-receiving element that emits and receives visible light.

[0541] The display panel 300B shown in Figure 25D includes a light-emitting element 311B, a light-emitting element 311G, and a light-receiving element 313R. The light-receiving element 313R has the function of a light-emitting element that emits red (R) light and a function of a photoelectric conversion element that receives visible light. Figure 25D shows an example in which the light-receiving element 313R receives green (G) light emitted by the light-emitting element 311G. The light-receiving element 313R may also receive blue (B) light emitted by the light-emitting element 311B. Furthermore, the light-receiving element 313R may receive both green and blue light.

[0542] For example, it is preferable that the light-receiving element 313R receives light with a shorter wavelength than the light it emits. Alternatively, the light-receiving element 313R may be configured to receive light with a longer wavelength than the light it emits (e.g., infrared light). The light-receiving element 313R may also be configured to receive light with a wavelength similar to the light it emits, but in that case, it may also receive the light it emits, which may reduce its luminous efficiency. Therefore, it is preferable that the light-receiving element 313R is configured such that the peaks of its emission spectrum and the peaks of its absorption spectrum do not overlap as much as possible.

[0543] Furthermore, the light emitted by the light-receiving element is not limited to red light. Nor is the light emitted by the light-emitting element limited to a combination of green and blue light. For example, the light-receiving element can emit green or blue light and receive light of a different wavelength than the light it emits.

[0544] In this way, by having the light-emitting element 313R serve as both a light-emitting element and a light-receiving element, the number of elements arranged in a single pixel can be reduced. This makes it easier to achieve higher resolution, higher aperture ratio, and higher resolution.

[0545] Figures 25E and 25F show examples of pixels applicable to the display panel 300B.

[0546] Figure 25E shows an example where the light-emitting element 313R, light-emitting element 311G, and light-emitting element 311B are arranged in a single row. Figure 25F shows an example where the light-emitting elements 311G and 311B are arranged alternately in the vertical direction, with the light-emitting element 313R positioned to the side of them.

[0547] The top surface shape of the light-emitting element and the light-receiving element is not particularly limited and can be a circle, ellipse, polygon, polygon with rounded corners, etc. Furthermore, the top surface shapes of the light-emitting element and the light-receiving element of each color may be different from each other, or they may be the same for some or all colors. Also, the size of the light-emitting area (or light-receiving area) of the light-emitting element and the light-receiving element of each color may be different from each other, or they may be the same for some or all colors.

[0548] For example, when detecting touch operations using a light-receiving element, it is preferable that the light emitted from the light source is not easily visible to the user. Since blue light is less visible than green light, it is preferable to use a light-emitting element that emits blue light as the light source. Therefore, it is preferable that the light-receiving element has the function of receiving blue light. However, it is not limited to this, and the light-emitting element used as the light source can be appropriately selected according to the sensitivity of the light-receiving element.

[0549] As described above, various pixel arrangements can be applied to the display device of this embodiment.

[0550] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0551] (Embodiment 5) In this embodiment, a light-emitting device (also called a light-emitting element) and a light-receiving device (also called a light-receiving element) that can be used in a light-receiving device which is one aspect of the present invention will be described.

[0552] [Light-emitting devices] As shown in Figure 26A, the light-emitting device has an EL layer 790 between a pair of electrodes (lower electrode 791, upper electrode 792). The EL layer 790 can be composed of multiple layers, such as layer 720, light-emitting layer 711, and layer 730. Layer 720 may include, for example, a layer containing a material with high electron injection properties (electron injection layer) and a layer containing a material with high electron transport properties (electron transport layer). The light-emitting layer 711 may include, for example, a light-emitting compound. Layer 730 may include, for example, a layer containing a material with high hole injection properties (hole injection layer) and a layer containing a material with high hole transport properties (hole transport layer).

[0553] A configuration having a layer 720, an emissive layer 711, and a layer 730 provided between a pair of electrodes can function as a single emissive unit, and in this specification, the configuration shown in Figure 26A is referred to as a single structure.

[0554] Furthermore, Figure 26B shows a modified example of the EL layer 790 of the light-emitting device shown in Figure 26A. Specifically, the light-emitting device shown in Figure 26B includes a layer 730-1 on the lower electrode 791, a layer 730-2 on layer 730-1, a light-emitting layer 711 on layer 730-2, a layer 720-1 on the light-emitting layer 711, a layer 720-2 on layer 720-1, and an upper electrode 792 on layer 720-2. For example, when the lower electrode 791 is the anode and the upper electrode 792 is the cathode, layer 730-1 functions as a hole injection layer, layer 730-2 functions as a hole transport layer, layer 720-1 functions as an electron transport layer, and layer 720-2 functions as an electron injection layer. Alternatively, when the lower electrode 791 is used as the cathode and the upper electrode 792 as the anode, layer 730-1 functions as an electron injection layer, layer 730-2 functions as an electron transport layer, layer 720-1 functions as a hole transport layer, and layer 720-2 functions as a hole injection layer. By using such a layer structure, it is possible to efficiently inject carriers into the light-emitting layer 711 and increase the efficiency of carrier recombination within the light-emitting layer 711.

[0555] Furthermore, as shown in Figures 26C and 26D, a configuration in which multiple light-emitting layers (light-emitting layers 711, 712, and 713) are provided between layer 720 and layer 730 is also a variation of the single structure.

[0556] Furthermore, as shown in Figures 26E and 26F, a configuration in which multiple light-emitting units (EL layer 790a, EL layer 790b) are connected in series via an intermediate layer 740 is referred to as a tandem structure in this specification. The intermediate layer 740 may also be referred to as a charge generation layer. In this specification, the configuration shown in Figures 26E and 26F is referred to as a tandem structure, but it is not limited to this, and for example, a tandem structure may also be called a stacked structure. By using a tandem structure, a light-emitting device capable of high-brightness light emission can be made.

[0557] In Figure 26C, the light-emitting layers 711, 712, and 713 may be made of the same light-emitting material.

[0558] Furthermore, different light-emitting materials may be used for the light-emitting layers 711, 712, and 713. When the light emitted by the light-emitting layers 711, 712, and 713 are complementary in color, white light emission is obtained. Figure 26D shows an example in which a colored layer 795, which functions as a color filter, is provided. By passing white light through the color filter, light of the desired color can be obtained.

[0559] Furthermore, in Figure 26E, the same light-emitting material may be used for both the light-emitting layer 711 and the light-emitting layer 712. Alternatively, light-emitting materials that emit different types of light may be used for both the light-emitting layer 711 and the light-emitting layer 712. When the light emitted by the light-emitting layer 711 and the light emitted by the light-emitting layer 712 are complementary colors, white light emission is obtained. Figure 26F shows an example in which a colored layer 795 is further provided.

[0560] Furthermore, in Figures 26C, 26D, 26E, and 26F, as shown in Figure 26B, layer 720 and layer 730 may be a laminated structure consisting of two or more layers.

[0561] Furthermore, in Figure 26D, the same light-emitting material may be used for light-emitting layers 711, 712, and 713. Similarly, in Figure 26F, the same light-emitting material may be used for light-emitting layers 711 and 712. In this case, by applying a color conversion layer instead of the colored layer 795, it is possible to obtain light of a desired color different from that of the light-emitting material. For example, by using a blue light-emitting material for each light-emitting layer, blue light can pass through the color conversion layer to obtain light with a longer wavelength than blue (e.g., red, green, etc.). Fluorescent materials, phosphorescent materials, or quantum dots can be used as the color conversion layer.

[0562] The light-emitting color of the light-emitting device can be red, green, blue, cyan, magenta, yellow, or white, depending on the material that makes up the EL layer 790. Furthermore, the color purity can be further enhanced by adding a microcavity structure to the light-emitting device.

[0563] A light-emitting device that emits white light preferably has a configuration that includes two or more types of light-emitting materials in its light-emitting layer. To obtain white light emission, it is sufficient to select light-emitting materials such that the light emitted by each of the two or more materials is complementary in color. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary, a light-emitting device that emits white light as a whole can be obtained. The same applies to light-emitting devices that have three or more light-emitting layers.

[0564] The light-emitting layer preferably contains two or more light-emitting materials that emit light such as R (red), G (green), B (blue), Y (yellow), and O (orange). Alternatively, it is preferable to have two or more light-emitting materials, and for each light-emitting material to emit light that contains spectral components of two or more colors from R, G, and B.

[0565] [Light receiving device] Figure 27A shows schematic cross-sectional views of the light-emitting devices 750R, 750G, 750B, and 760. The light-emitting devices 750R, 750G, 750B, and 760 all share a common upper electrode 792 layer.

[0566] The light-emitting device 750R has a pixel electrode 791R, layers 751 and 752, a light-emitting layer 753R, layers 754 and 755, and an upper electrode 792. The light-emitting device 750G has a pixel electrode 791G and a light-emitting layer 753G. The light-emitting device 750B has a pixel electrode 791B and a light-emitting layer 753B.

[0567] Layer 751 includes, for example, a layer containing a material with high hole injection properties (hole injection layer). Layer 752 includes, for example, a layer containing a material with high hole transport properties (hole transport layer). Layer 754 includes, for example, a layer containing a material with high electron transport properties (electron transport layer). Layer 755 includes, for example, a layer containing a material with high electron injection properties (electron injection layer).

[0568] Alternatively, the configuration may include layer 751 having an electron injection layer, layer 752 having an electron transport layer, layer 754 having a hole transport layer, and layer 755 having a hole injection layer.

[0569] Note that in Figure 27A, layers 751 and 752 are shown separately, but this is not the only way. For example, if layer 751 has the functions of both a hole injection layer and a hole transport layer, or if layer 751 has the functions of both an electron injection layer and an electron transport layer, then layer 752 may be omitted.

[0570] Furthermore, the light-emitting layer 753R of the light-emitting device 750R contains a light-emitting material that emits red light, the light-emitting layer 753G of the light-emitting device 750G contains a light-emitting material that emits green light, and the light-emitting layer 753B of the light-emitting device 750B contains a light-emitting material that emits blue light. The light-emitting devices 750G and 750B have a configuration in which the light-emitting layer 753R of the light-emitting device 750R is replaced with the light-emitting layer 753G and light-emitting layer 753B, respectively, and the other configurations are the same as those of the light-emitting device 750R.

[0571] Layers 751, 752, 754, and 755 may have the same configuration (material, film thickness, etc.) for each color of light-emitting device, or they may have different configurations from each other.

[0572] The light-receiving device 760 has a pixel electrode 791PD, layers 761, 762, 763, and an upper electrode 792. The light-receiving device 760 can be configured without a hole injection layer and an electron injection layer.

[0573] Layer 762 has an active layer (also called a photoelectric conversion layer). Layer 762 has the function of absorbing light in a specific wavelength band and generating carriers (electrons and holes).

[0574] Layers 761 and 763 each have, for example, either a hole transport layer or an electron transport layer. If layer 761 has a hole transport layer, then layer 763 has an electron transport layer. Conversely, if layer 761 has an electron transport layer, then layer 763 has a hole transport layer.

[0575] Furthermore, the light-receiving device 760 may have the pixel electrode 791PD as the anode and the upper electrode 792 as the cathode, or the pixel electrode 791PD as the cathode and the upper electrode 792 as the anode.

[0576] Figure 27B is a modified example of Figure 27A. In Figure 27B, layer 755 is provided in common between each light-emitting device and between each photodetector, similar to the upper electrode 792. In this case, layer 755 can be called a common layer. By providing one or more common layers between each light-emitting device and between each photodetector, the manufacturing process can be simplified, thereby reducing manufacturing costs.

[0577] Here, layer 755 functions as an electron injection layer or a hole injection layer for the light-emitting device 750. At the same time, it functions as an electron transport layer or a hole transport layer for the light-receiving device 760. Therefore, the light-receiving device 760 shown in Figure 27B does not need to have a layer 763 that functions as an electron transport layer or a hole transport layer.

[0578] The above is a description of the light-receiving device.

[0579] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0580] (Embodiment 6) This embodiment describes metal oxides (also called oxide semiconductors) that can be used in the OS transistor described in the above embodiment.

[0581] The metal oxide used in the OS transistor preferably contains at least indium or zinc, and more preferably indium and zinc. For example, the metal oxide preferably contains indium, M (where M is one or more selected from gallium, aluminum, yttrium, tin, silicon, boron, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt), and zinc. In particular, M is preferably one or more selected from gallium, aluminum, yttrium, and tin, and more preferably gallium.

[0582] Metal oxides can be formed by methods such as sputtering, CVD (Chemical Vapor Deposition) methods including MOCVD, or ALD (Artificial Alkaline Dissolution).

[0583] In the following sections, we will describe oxides containing indium (In), gallium (Ga), and zinc (Zn) as examples of metal oxides. Note that oxides containing indium (In), gallium (Ga), and zinc (Zn) are sometimes called In-Ga-Zn oxides.

[0584] <Classification of crystal structures> Examples of crystalline structures for oxide semiconductors include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and polycrystal.

[0585] The crystal structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectroscopy. For example, it can be evaluated using the XRD spectrum obtained from a GIXD (Grazing-Incidence XRD) measurement. The GIXD method is also known as the thin-film method or the Seemann-Bohlin method. In the following text, the XRD spectrum obtained from a GIXD measurement may simply be referred to as the XRD spectrum.

[0586] For example, in a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, in an In-Ga-Zn oxide film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical shape of the XRD spectrum peaks clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0587] Furthermore, the crystalline structure of a film or substrate can be evaluated by the diffraction pattern (also called the nano-beam electron diffraction pattern) observed using nano-beam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, confirming that the quartz glass is in an amorphous state. On the other hand, a spot-like pattern is observed in the diffraction pattern of an In-Ga-Zn oxide film deposited at room temperature, rather than a halo. Therefore, it is presumed that the In-Ga-Zn oxide deposited at room temperature is in an intermediate state, neither single-crystal nor polycrystalline, nor amorphous, and cannot be concluded to be in an amorphous state.

[0588] <<Oxide semiconductor structure>> It should be noted that oxide semiconductors may be classified differently from those described above when considering their structure. For example, oxide semiconductors can be divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the aforementioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors also include polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0589] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0590] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, the c-axis of which is oriented in a specific direction. This specific direction is the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region with periodic atomic arrangement. If we consider the atomic arrangement as a lattice arrangement, then a crystalline region is also a region with a aligned lattice arrangement. Furthermore, CAAC-OS has regions where multiple crystalline regions are connected in the ab-plane direction, and these regions may exhibit distortion. Distortion refers to a point in the connected region where the orientation of the lattice arrangement changes between a region with a aligned lattice arrangement and another region with a aligned lattice arrangement. In short, CAAC-OS is an oxide semiconductor that is c-axis oriented and does not exhibit clear orientation in the ab-plane direction.

[0591] Each of the above-mentioned crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of one minute crystal, the maximum diameter of that crystalline region will be less than 10 nm. When a crystalline region is composed of many minute crystals, the maximum diameter of that crystalline region may be around several tens of nm.

[0592] Furthermore, in In-Ga-Zn oxides, CAAC-OS tends to have a layered crystalline structure (also called a layered structure) consisting of layers containing indium (In) and oxygen (hereinafter referred to as the In layer) and layers containing gallium (Ga), zinc (Zn), and oxygen (hereinafter referred to as the (Ga,Zn) layer). Note that indium and gallium are mutually substitutable. Therefore, the (Ga,Zn) layer may contain indium. Also, the In layer may contain gallium. Also, the In layer may contain zinc. This layered structure can be observed, for example, as a lattice image in high-resolution TEM (Transmission Electron Microscope) images.

[0593] When structural analysis of a CAAC-OS film is performed using an XRD instrument, for example, out-of-plane XRD measurements using θ / 2θ scanning show a peak indicating c-axis orientation at 2θ = 31° or nearby. Note that the position of the c-axis orientation peak (value of 2θ) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0594] Furthermore, for example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film. These spots are observed at point-symmetric positions with respect to the incident electron beam spot (also called the direct spot) that passed through the sample.

[0595] When the crystal region is observed from the specific direction described above, the lattice arrangement within that crystal region is based on a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the strain may have lattice arrangements such as pentagons or heptagons. Moreover, in CAAC-OS, clear grain boundaries cannot be observed even near the strain. In other words, it can be seen that the formation of grain boundaries is suppressed by the strain in the lattice arrangement. This is thought to be because CAAC-OS can tolerate strain due to the fact that the arrangement of oxygen atoms is not dense in the ab-plane direction, and the bond distance between atoms changes due to the substitution of metal atoms.

[0596] Furthermore, a crystal structure in which clear grain boundaries can be observed is called a polycrystalline material. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in transistor on-current and field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries cannot be observed, is one of the crystalline oxides with a suitable crystal structure for the semiconductor layer of a transistor. In addition, a structure containing Zn is preferred for the composition of CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are preferred because they can suppress the generation of grain boundaries more effectively than In oxide.

[0597] CAAC-OS is an oxide semiconductor with high crystallinity and no clearly defined grain boundaries. Therefore, CAAC-OS is less susceptible to the decrease in electron mobility caused by grain boundaries. Furthermore, since the crystallinity of oxide semiconductors can decrease due to the inclusion of impurities and the generation of defects, CAAC-OS can be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Consequently, oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat-resistant and highly reliable. In addition, CAAC-OS is stable even at high temperatures (so-called thermal budget) during the manufacturing process. Therefore, using CAAC-OS in OS transistors allows for greater flexibility in the manufacturing process.

[0598] [nc-OS] nc-OS exhibits periodicity in atomic arrangement in minute regions (e.g., regions between 1 nm and 10 nm, particularly between 1 nm and 3 nm). In other words, nc-OS contains minute crystals. These minute crystals are also called nanocrystals because their size is, for example, between 1 nm and 10 nm, particularly between 1 nm and 3 nm. Furthermore, nc-OS shows no regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Consequently, depending on the analytical method, nc-OS may be indistinguishable from a-like OS or amorphous oxide semiconductors. For example, when structural analysis of an nc-OS film is performed using an XRD instrument, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Also, when electron diffraction (also called limited-field electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of the nanocrystals (e.g., 50 nm or larger), a diffraction pattern resembling a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystal (for example, 1 nm to 30 nm), an electron diffraction pattern may be obtained in which multiple spots are observed within a ring-shaped region centered on a direct spot.

[0599] [a-like OS] a-like OS is an oxide semiconductor having a structure between nc-OS and amorphous oxide semiconductors. a-like OS has porous or low-density regions. In other words, a-like OS has lower crystallinity compared to nc-OS and CAAC-OS. Also, a-like OS has a higher hydrogen concentration in the film compared to nc-OS and CAAC-OS.

[0600] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0601] [CAC-OS] CAC-OS is a material composition in which, for example, the elements constituting the metal oxide are unevenly distributed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size. In the following, a state in which one or more metal elements are unevenly distributed in a metal oxide, and the regions containing these metal elements are mixed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size, is also referred to as a mosaic or patchy state.

[0602] Furthermore, CAC-OS is a composite metal oxide having a mosaic-like structure formed by the separation of the material into a first region and a second region, with the first region distributed within the film (hereinafter also referred to as a cloud-like structure). In other words, CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0603] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS of In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of the CAC-OS film. The second region is the region where [Ga] is greater than the [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is the region where [In] is greater than the [In] in the second region, and [Ga] is smaller than the [Ga] in the second region. The second region is the region where [Ga] is greater than the [Ga] in the first region, and [In] is smaller than the [In] in the first region.

[0604] Specifically, the first region described above is a region whose main components are indium oxide, indium zinc oxide, etc. The second region described above is a region whose main components are gallium oxide, gallium zinc oxide, etc. In other words, the first region can be rephrased as a region whose main component is In. Similarly, the second region can be rephrased as a region whose main component is Ga.

[0605] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

[0606] Furthermore, CAC-OS in In-Ga-Zn oxide refers to a material composition containing In, Ga, Zn, and O, in which regions with Ga as the main component and regions with In as the main component are arranged in a mosaic-like fashion, with these regions existing randomly. Therefore, it is presumed that CAC-OS has a structure in which the metallic elements are unevenly distributed.

[0607] CAC-OS can be formed, for example, by sputtering under conditions where the substrate is not heated. When forming CAC-OS by sputtering, one or more gases selected from inert gases (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. Furthermore, a lower ratio of the oxygen gas flow rate to the total deposition gas flow rate during deposition is preferable. For example, the ratio of the oxygen gas flow rate to the total deposition gas flow rate during deposition should be 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0608] Furthermore, for example, in the case of CAC-OS in In-Ga-Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) confirms that it has a structure in which regions mainly composed of In (first region) and regions mainly composed of Ga (second region) are unevenly distributed and mixed.

[0609] Here, the first region is a region with higher conductivity compared to the second region. In other words, the conductivity of the metal oxide is exhibited when carriers flow through the first region. Therefore, a high field-effect mobility (μ) can be achieved when the first region is distributed in a cloud-like manner within the metal oxide.

[0610] On the other hand, the second region is a region with higher insulating properties compared to the first region. In other words, the distribution of the second region within the metal oxide can suppress leakage current.

[0611] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulation due to the second region work complementaryly to give CAC-OS a switching function (on / off function). In other words, CAC-OS has conductive function in part of the material, insulating function in part of the material, and semiconductor function as a whole. By separating the conductive function and the insulating function, both functions can be maximized. Therefore, by using CAC-OS in a transistor, a high on-current (I on This enables high field-effect mobility (μ) and good switching operation.

[0612] Furthermore, transistors using CAC-OS offer high reliability. Therefore, CAC-OS is ideal for various semiconductor devices, including display devices.

[0613] Oxide semiconductors can take on diverse structures, each possessing different properties. One embodiment of the present invention may include two or more of the following: amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0614] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0615] By using the above-mentioned oxide semiconductor in transistors, transistors with high field-effect mobility can be realized. Furthermore, highly reliable transistors can be achieved.

[0616] It is preferable to use an oxide semiconductor with a low carrier concentration for the transistor. For example, the carrier concentration of an oxide semiconductor is 1 × 10⁻⁶. 17 cm-3 The following is preferably 1 × 10 15 cm -3 More preferably 1 × 10 13 cm -3 More preferably 1 × 10 11 cm -3 More preferably 1 × 10 10 cm -3 It is less than 1 × 10 -9 cm -3 This concludes the explanation. Furthermore, when lowering the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film should be lowered to reduce the defect level density. In this specification, a low impurity concentration and low defect level density are referred to as high-purity intrinsic or substantially high-purity intrinsic. Note that oxide semiconductors with low carrier concentrations are sometimes referred to as high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors.

[0617] Furthermore, oxide semiconductor films that are highly intrinsic or substantially highly intrinsic may have a low trap level density due to their low defect level density.

[0618] Furthermore, charges trapped in the trap levels of oxide semiconductors can take a long time to disappear, sometimes behaving like fixed charges. Therefore, transistors in which channel formation regions are formed in oxide semiconductors with a high trap level density may exhibit unstable electrical properties.

[0619] Therefore, reducing the impurity concentration in the oxide semiconductor is effective in stabilizing the electrical characteristics of a transistor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in adjacent films. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon. Note that impurities in an oxide semiconductor refer to elements other than the main components that make up the oxide semiconductor. For example, elements with a concentration of less than 0.1 atomic percent can be considered impurities.

[0620] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0621] In oxide semiconductors, the presence of silicon or carbon, which are both Group 14 elements, leads to the formation of defect levels in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor (the concentration obtained by secondary ion mass spectrometry (SIMS)) is 2 × 10⁻¹⁰. 18 atoms / cm 3 The following is preferably 2 × 10 17 atoms / cm 3 The following applies:

[0622] Furthermore, if an oxide semiconductor contains alkali metals or alkaline earth metals, it may form defect levels and generate carriers. Therefore, transistors using oxide semiconductors containing alkali metals or alkaline earth metals tend to exhibit normally-on characteristics. For this reason, the concentration of alkali metals or alkaline earth metals in the oxide semiconductor obtained by SIMS should be set to 1 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 16 atoms / cm 3 Do the following:

[0623] Furthermore, in oxide semiconductors, the presence of nitrogen generates electrons, which act as carriers, increasing the carrier concentration and making it easier for the semiconductor to become n-type. As a result, transistors using oxide semiconductors containing nitrogen tend to exhibit normally-on characteristics. Alternatively, the presence of nitrogen in oxide semiconductors can lead to the formation of trap levels. As a result, the electrical properties of the transistor may become unstable. For this reason, the nitrogen concentration in oxide semiconductors obtained by SIMS should be set to 5 × 10⁻⁶. 19 atoms / cm 3 Less than 5 × 10 18 atoms / cm 3 More preferably 1 × 10 18 atoms / cm 3 More preferably 5 × 1017 atoms / cm 3 Do the following:

[0624] Furthermore, hydrogen contained in oxide semiconductors can react with oxygen bonded to metal atoms to form water, potentially creating oxygen vacancies. Hydrogen can then fill these vacancies, generating electrons as carriers. Additionally, some of the hydrogen can combine with oxygen bonded to metal atoms to generate electrons. Therefore, transistors using oxide semiconductors containing hydrogen tend to exhibit normally-on characteristics. For this reason, it is preferable to reduce the hydrogen content in oxide semiconductors as much as possible. Specifically, the hydrogen concentration in the oxide semiconductor obtained by SIMS should be 1 × 10⁻⁶. 20 atoms / cm 3 Less than 1 × 10 19 atoms / cm 3 Less than 5x10 18 atoms / cm 3 Less than 1 × 10 18 atoms / cm 3 Make it less than.

[0625] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be provided.

[0626] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0627] (Embodiment 7) In this embodiment, an example of a laminated panel configuration, which is one type of display panel that can be easily enlarged, and an example of its application will be described with reference to the drawings.

[0628] One aspect of the present invention is a display panel that can be enlarged by arranging multiple display panels so that they partially overlap. Furthermore, of the two overlapping display panels, at least the display panel located on the display surface side (upper panel) has a portion adjacent to the display area that transmits visible light. The pixels of the lower display panel and the visible light-transmitting portion of the upper display panel are arranged to overlap. As a result, when the two display panels are viewed from the display surface side (in a plan view), the images displayed on them can be displayed seamlessly and continuously.

[0629] For example, one aspect of the present invention is a laminated panel having a first display panel and a second display panel. The first display panel has a first region, the first region having a first pixel and a second pixel. The second display panel has a second region, a third region and a fourth region. The second region has a third pixel, the third region has the function of transmitting visible light, and the fourth region has the function of blocking visible light. Furthermore, the second pixel of the first display panel and the third region of the second display panel have overlapping regions. It is also preferable that the aperture ratio of the second pixel is greater than that of the first pixel.

[0630] One or both of the first and second display panels may be a display device equipped with a light-emitting element and a light-receiving element, as illustrated above. In other words, at least one of the first pixel, second pixel, and third pixel may have a light-emitting element and a light-receiving element.

[0631] More specifically, the configuration can be as follows:

[0632] [Configuration Example 1] [Display Panel] Figure 28A is a schematic top view of a display panel 500 included in a display device according to one embodiment of the present invention.

[0633] The display panel 500 includes a display area 501, a visible light-transmitting area 510 adjacent to the display area 501, and an area 520 having a portion that blocks visible light. Figure 28A shows an example in which an FPC 512 is provided on the display panel 500.

[0634] Here, the display panel 500 can display an image in the displ...

Claims

1. The substrate has a first light-emitting element, a second light-emitting element, a first insulating layer, and a second insulating layer. The first light-emitting element described above includes a first pixel electrode, a first organic layer, and a common electrode. The second light-emitting element comprises a second pixel electrode, a second organic layer, and the common electrode. The first insulating layer covers the end of the first pixel electrode, The first organic layer is provided on the first pixel electrode and the first insulating layer. The second insulating layer is provided on the first organic layer and on the first insulating layer, The second insulating layer has a portion of the upper surface and side surface of the first organic layer, and a region in contact with a portion of the upper surface of the first insulating layer. In a top view of the substrate, the first light-emitting element has a first side and a second side that is shorter than the first side. The absolute value of the difference between the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the first direction, and the chromaticity difference Δu'v' between the chromaticity in the front direction and the chromaticity in the second direction, is 0.05 or less. The projection of the first direction onto the substrate is parallel to the first side, The projection of the second direction onto the substrate is parallel to the second side, The angle between the first direction and the normal direction of the substrate surface is 70°. The angle between the second direction and the normal direction of the substrate surface is 70°. Display device.

2. In claim 1, In a top view of the first light-emitting element, in the region where the first pixel electrode and the common electrode overlap via the light-emitting region of the first organic layer, the entire surface of the first pixel electrode on the first organic layer side and the entire surface of the common electrode on the first organic layer side are parallel or substantially parallel. Display device.

3. In claim 1 or 2, The end of the first insulating layer is tapered, The second insulating layer has a region that overlaps with the edge of the first insulating layer via the first organic layer. Display device.

4. In any one of claims 1 to 3, It further has an insulating layer, The end of the first pixel electrode and the end of the first organic layer coincide or substantially coincide. The end of the second pixel electrode and the end of the second organic layer coincide or substantially coincide. The insulating layer has regions that are in contact with the sides of the first pixel electrode, the second pixel electrode, the first organic layer, and the second organic layer. Display device.

5. In any one of claims 1 to 3, It further has an insulating layer, The width of the first pixel electrode is smaller than the width of the first organic layer. The width of the second pixel electrode is smaller than the width of the second organic layer. The first organic layer covers the side and top surfaces of the first pixel electrode. The second organic layer covers the side and top surfaces of the second pixel electrode. The insulating layer has a portion of the upper surface and a region that is in contact with the side surface of the first organic layer and the second organic layer, respectively. Display device.

6. In any one of claims 1 to 5, The first light-emitting element has a common layer between the first organic layer and the common electrode. The second light-emitting element has the common layer between the second organic layer and the common electrode. Display device.

7. In claim 6, The common layer has either an electron transport layer or an electron injection layer, or both. Display device.

8. In any one of claims 1 to 7, The substrate is flexible, The shape of the substrate is non-rectangular. Display device.

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