Electronic apparatus

Abstract

Provided is an electronic apparatus with which a high sense of immersion can be obtained. Provided is an electronic apparatus with low power consumption. Provided is an electronic apparatus. A first display device includes a plurality of first pixels. The first pixels include a light-emitting element that emits green light. A second display device includes a plurality of second pixels. The second pixels include a light-emitting element that emits red light and a light-emitting element that emits blue light. The first display device and the second display device having a function for displaying a first image and a second image, respectively. The first display device is provided at a position where the first image reflects from a first half mirror and is incident on an eyepiece. The second display device is provided at a position where the second image is transmitted through the first half mirror and is incident on the eyepiece. The first image and the second image are presented individually via the eyepiece.

Description

electronic equipment

[0001] FIELD OF THE INVENTION One embodiment of the present invention relates to a display device and an electronic device including the display device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention disclosed in this specification and the like include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices, input / output devices, driving methods thereof, and manufacturing methods thereof. A semiconductor device refers to any device that can function by utilizing semiconductor characteristics.

[0003] Wearable electronic devices that are equipped with display devices for augmented reality (AR) or virtual reality (VR) are becoming increasingly popular. Examples of wearable electronic devices include head-mounted displays (HMDs) and eyeglass-type electronic devices.

[0004] In electronic devices such as HMDs, where the display unit is close to the user, the user can easily see the pixels, which can cause a strong sense of graininess, which can reduce the sense of immersion or realism in AR or VR. For this reason, it is preferable to provide the HMD with a display device having fine pixels so that the pixels are not visible to the user. Patent Document 1 discloses a method for realizing an HMD with fine pixels by using fine transistors that can be driven at high speed.

[0005] Japanese Patent Application Laid-Open No. 2000-2856

[0006] An object of one embodiment of the present invention is to provide an electronic device that can provide a high sense of immersion. Another object is to provide an electronic device with high display quality. Another object is to provide an electronic device that can display an image with a higher resolution as the image is closer to a point of gaze. Another object is to provide an electronic device with low power consumption. Another object is to provide an electronic device that can be manufactured at low cost. Another object is to provide an electronic device with a novel structure.

[0007] An object of one embodiment of the present invention is to provide a display device or an electronic device having a novel structure. An object of one embodiment of the present invention is to alleviate at least one of the problems of the prior art.

[0008] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description of the specification, drawings, claims, etc.

[0009] One embodiment of the present invention includes a first display device, a second display device, a first half mirror, and an eyepiece. The first display device includes a plurality of first pixels, each of which has a light-emitting element that exhibits a first color. The second display device includes a plurality of second pixels, each of which has a light-emitting element that exhibits the second color and a light-emitting element that exhibits a third color. The first color is one of green and blue, the second color is red, and the third color is green and blue. The other is an electronic device in which the first display device has a function of displaying a first image, the second display device has a function of displaying a second image, the first display device is provided at a position where the first image is reflected by a first half mirror and enters an eyepiece, the second display device is provided at a position where the second image is transmitted through the first half mirror and enters the eyepiece, and the first image is presented through the eyepiece and the second image is presented through the eyepiece, superimposed on the first image.

[0010] Alternatively, one embodiment of the present invention includes a first display device, a second display device, a first half mirror, and an eyepiece. The first display device includes a plurality of first pixels, each of which has a light-emitting element that exhibits a first color. The second display device includes a plurality of second pixels, each of which has a light-emitting element that exhibits the second color and a light-emitting element that exhibits a third color. The first color is one of green and blue, the second color is red, and the third color is green and blue. The other is blue, and the first display device has the function of displaying a first image, and the second display device has the function of displaying a second image, the first display device is provided at a position where the first image passes through a first half mirror and enters an eyepiece, and the second display device is provided at a position where the second image is reflected by the first half mirror and enters the eyepiece, and the first image is presented through the eyepiece, and the second image is presented through the eyepiece, superimposed on the first image.

[0011] In the above configuration, it is preferable that the pixel density of the first pixels in the first display device is equal to the pixel density of the second pixels in the second display device.

[0012] In the above configuration, it is preferable that the pixel density of the first pixel in the first display device is 1000 ppi or more and 20000 ppi or less.

[0013] Alternatively, one embodiment of the present invention includes a first display device, a second display device, a first half mirror, and an eyepiece. The first display device has a plurality of first subpixels arranged in a matrix, and each of the plurality of first subpixels has a light-emitting element that exhibits a first color. The second display device has a plurality of second subpixels arranged in a matrix and a plurality of third subpixels arranged in a matrix, and each of the plurality of second subpixels has a light-emitting element that exhibits a second color. Each of the plurality of third subpixels has a light-emitting element that exhibits a third color, and the first color is one of green and blue, the second color is red, and the third color is the other of green and blue. the pixel density of the first subpixel in the first display device is greater than the pixel density of the second subpixel in the second display device, and in the second display device, the second subpixels and the third subpixels are arranged alternately in the horizontal direction and in the vertical direction in a planar view, the first display device has a function of displaying a first image, the second display device has a function of displaying a second image, the first display device is provided at a position where the first image is reflected by a first half mirror and enters an eyepiece, and the second display device is provided at a position where the second image is transmitted through the first half mirror and enters the eyepiece, and the first image is presented via the eyepiece and the second image is presented via the eyepiece.

[0014] Alternatively, one embodiment of the present invention includes a first display device, a second display device, a first half mirror, and an eyepiece. The first display device has a plurality of first subpixels arranged in a matrix, and each of the plurality of first subpixels has a light-emitting element that exhibits a first color. The second display device has a plurality of second subpixels arranged in a matrix and a plurality of third subpixels arranged in a matrix, and each of the plurality of second subpixels has a light-emitting element that exhibits a second color. Each of the plurality of third subpixels has a light-emitting element that exhibits a third color, and the first color is one of green and blue, the second color is red, and the third color is the other of green and blue. the pixel density of the first subpixel in the first display device is greater than the pixel density of the second subpixel in the second display device, and in the second display device, the second subpixels and the third subpixels are arranged alternately in the horizontal direction and in the vertical direction in a planar view, the first display device has a function of displaying a first image, the second display device has a function of displaying a second image, the first display device is provided at a position where the first image passes through a first half mirror and enters an eyepiece, and the second display device is provided at a position where the second image is reflected by the first half mirror and enters the eyepiece, and the first image is presented via the eyepiece and the second image is presented via the eyepiece.

[0015] Furthermore, in the above configuration, it is preferable that the first image and the second image are presented through the eyepiece as an overlapping third image, and that in the third image, the first sub-pixel has a first region that overlaps with one of the plurality of second sub-pixels, a second region that overlaps with one of the plurality of third sub-pixels, and a third region that does not overlap with either one of the plurality of second sub-pixels or one of the plurality of third sub-pixels.

[0016] Alternatively, one embodiment of the present invention includes a first display device, a second display device, a first half mirror, and an eyepiece. The first display device includes a first display portion. The second display device includes a second display portion and a third display portion. The third display portion is provided to surround at least a part of the second display portion in a plan view. The first display portion includes a plurality of first pixels. Each of the plurality of first pixels includes a light-emitting element that exhibits a first color. The display unit has a plurality of second pixels, each of which has a light-emitting element that exhibits a second color and a light-emitting element that exhibits a third color; the third display unit has a plurality of third pixels, each of which has a light-emitting element that exhibits a first color, a light-emitting element that exhibits a second color, and a light-emitting element that exhibits a third color, the first color being one of green and blue, the second color being red, and the third color being the other of green and blue; the pixel density of the third pixel in the display unit is lower than the pixel density of the first pixel in the first display unit and the pixel density of the second pixel in the second display unit; the first display unit has a function of displaying a first image, the second display unit has a function of displaying a second image, and the third display unit has a function of displaying a third image; the first display device is provided at a position where the first image is reflected by a first half mirror and enters an eyepiece; the second display device is provided at a position where the second image and the third image are transmitted through the first half mirror and enter the eyepiece; the first image is presented through the eyepiece, the second image is presented through the eyepiece superimposed on the first image, and the third image is presented through the eyepiece; and the third image presented through the eyepiece is presented in an area surrounding the first image presented through the eyepiece and the second image presented through the eyepiece.

[0017] Alternatively, one embodiment of the present invention includes a first display device, a second display device, a first half mirror, and an eyepiece. The first display device includes a first display portion. The second display device includes a second display portion and a third display portion. The third display portion is provided to surround at least a part of the second display portion in a plan view. The first display portion includes a plurality of first pixels. Each of the plurality of first pixels includes a light-emitting element that exhibits a first color. the display unit has a plurality of second pixels, each of which has a light-emitting element that exhibits a second color and a light-emitting element that exhibits a third color; the third display unit has a plurality of third pixels, each of which has a light-emitting element that exhibits a first color, a light-emitting element that exhibits a second color, and a light-emitting element that exhibits a third color, the first color being one of green and blue, the second color being red, and the third color being the other of green and blue; The pixel density of the third pixel in the display unit is lower than the pixel density of the first pixel in the first display unit and the pixel density of the second pixel in the second display unit, the first display unit has a function of displaying a first image, the second display unit has a function of displaying a second image, and the third display unit has a function of displaying a third image, the first display device is provided at a position where the first image passes through a first half mirror and enters an eyepiece, the second display device is provided at a position where the second image and the third image are reflected by the first half mirror and enter the eyepiece, the first image is presented through the eyepiece, the second image is presented through the eyepiece superimposed on the first image, the third image is presented through the eyepiece, and the third image presented through the eyepiece is presented in an area surrounding the first image presented through the eyepiece and the second image presented through the eyepiece.

[0018] In the above configuration, it is preferable that the pixel density of the first pixel in the first display portion is 1000 ppi or more and 20000 ppi or less, and the pixel density of the third pixel in the third display portion is 50 ppi or more and less than 1000 ppi.

[0019] According to one embodiment of the present invention, an electronic device that can provide a high sense of immersion can be provided. Alternatively, an electronic device with high display quality can be provided. Alternatively, an electronic device that can display an image with higher resolution as the image approaches a point of gaze can be provided. Alternatively, an electronic device with low power consumption can be provided. Alternatively, an electronic device that can be manufactured at low cost can be provided. Alternatively, an electronic device with a novel structure can be provided.

[0020] According to one aspect of the present invention, it is possible to provide a display device or an electronic device having a novel configuration. According to one aspect of the present invention, it is possible to at least alleviate at least one of the problems of the prior art.

[0021] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these can be extracted from the description in the specification, drawings, claims, etc.

[0022] FIGS. 1A and 1B are diagrams illustrating an example of the configuration of an electronic device. FIGS. 2A and 2B are diagrams illustrating an example of the configuration of an electronic device. FIGS. 3A and 3B are diagrams illustrating an example of the configuration of an electronic device. FIGS. 4A and 4B are diagrams illustrating an example of the configuration of an electronic device. FIGS. 5A and 5B are diagrams illustrating an example of the configuration of a display device. FIGS. 6A and 6B are diagrams illustrating an example of the configuration of a display device. FIGS. 7A and 7B are diagrams illustrating an example of the configuration of a display device. FIGS. 8A and 8B are diagrams illustrating an example of the configuration of a display device. FIGS. 9A, 9B, and 9C are diagrams illustrating an example of the configuration of a display device. FIG. 10 is a diagram illustrating an example of the configuration of a display device. FIGS. 11A to 11D are cross-sectional views showing an example of the configuration of a display device. FIGS. 12A and 12B are diagrams illustrating an example of the configuration of an electronic device. FIG. 13A is a plan view showing an example of the configuration of a display unit. FIG. 13B is a diagram illustrating an example of the configuration of an electronic device. FIG. 14 is a cross-sectional view showing an example of the configuration of a display device. FIGS. 15A to 15C are cross-sectional views showing an example of the configuration of a display device. 16A to 16C are cross-sectional views showing an example of the configuration of a display device. FIGS. 17A and 17B are cross-sectional views showing an example of the configuration of a display device. FIGS. 18A and 18B are block diagrams showing an example of the configuration of a display device. FIG. 19 is a perspective view showing an example of the configuration of a display device. FIG. 20 is a perspective view showing an example of the configuration of a display module. FIG. 21 is a cross-sectional view showing an example of the configuration of a display device. FIG. 22 is a cross-sectional view showing an example of the configuration of a display device. FIG. 23 is a cross-sectional view showing an example of the configuration of a display device. FIG. 24 is a cross-sectional view showing an example of the configuration of a display device. FIG. 25 is a cross-sectional view showing an example of the configuration of a display device. FIG. 26 is a cross-sectional view showing an example of the configuration of a display device. FIG. 27 is a perspective view showing an example of the configuration of a display device. FIG. 28A is a cross-sectional view showing an example of the configuration of a display device. FIGS. 28B and 28C are cross-sectional views showing examples of the configuration of a transistor. FIGS. 29A to 29F are cross-sectional views showing an example of the configuration of a light-emitting element. FIGS. 30A to 30C are cross-sectional views showing an example of the configuration of a light-emitting element.

[0023] Hereinafter, embodiments will be described with reference to the drawings. However, it will be readily understood by those skilled in the art that the embodiments can be implemented in many different ways and that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the following description of the embodiments.

[0024] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted. Furthermore, when referring to similar functions, the same hatching pattern may be used and no particular reference numeral may be assigned.

[0025] In the drawings described in this specification, the size of each component, the thickness of a layer, or an area may be exaggerated for clarity, and therefore, the drawings are not necessarily limited to the scale.

[0026] In this specification, ordinal numbers such as "first" and "second" are used to avoid confusion of components and do not limit the number.

[0027] In this specification and the like, a display panel, which is one aspect of a display device, has a function of displaying (outputting) an image or the like on a display surface, and therefore the display panel is one aspect of an output device.

[0028] In addition, in this specification, a display panel having a connector such as an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package) attached to the substrate, or a display panel having an IC mounted on the substrate using a COG (Chip On Glass) method or the like, may be referred to as a display panel module, a display module, or simply a display panel.

[0029] Embodiment 1 In this embodiment, an electronic device according to one embodiment of the present invention will be described.

[0030] An electronic device according to one embodiment of the present invention is a head-mountable electronic device. The electronic device can present a three-dimensional image to a user using parallax. That is, the electronic device can be used as a VR device. The electronic device may also have a function of displaying a forward view captured by a camera (also referred to as a video see-through function). Furthermore, the electronic device can perform so-called AR display, in which another image is composited with the forward view and displayed.

[0031] The electronic device has two display devices (a first display device and a second display device) and an eyepiece, through which a user can view an image that is a composite of a first image displayed by the first display device and a second image displayed by the second display device.

[0032] More specifically, the electronic device preferably includes a half mirror. One of the first image and the second image passes through the half mirror and reaches the eyepiece, while the other is reflected by the half mirror and reaches the eyepiece. By arranging the first display device, the second display device, the half mirror, and the eyepiece in this manner, the user can view a superimposed (composite) image of the first image and the second image through the eyepiece.

[0033] In this specification, the viewing angle of an electronic device refers to the range in which a user can view an image through an optical component such as a lens. Unless otherwise specified, the term "viewing angle" refers to the horizontal viewing angle. The viewing angle can be divided into a viewing angle per eye and a viewing angle with both eyes, with the viewing angle with both eyes generally being wider. The viewing angle is also sometimes called FOV (Field of View).

[0034] More specific examples of electronic devices will be described below with reference to the drawings.

[0035] 1A and 1B are perspective views of a portion of an electronic device 10 according to one embodiment of the present invention. The electronic device 10 includes a display device 11a, a display device 11b, a lens 12, and a half mirror 14. FIG. 1A shows a trajectory of light (image) emitted by the display device 11a, and FIG. 1B shows a trajectory of light emitted by the display device 11b. Also, FIGS. 1A and 1B schematically show a user's eye 20 near the lens 12. Furthermore, FIG. 2A is a schematic diagram of the electronic device 10 viewed from a direction perpendicular to the optical axis of the lens 12.

[0036] The display device 11a includes an element emitting light of a first color selected from red (R), green (G), and blue (B). The display device 11b includes an element emitting light of a second color selected from red, green, and blue, and an element emitting light of a third color selected from red, green, and blue. Each of the display devices 11a and 11b has a function of displaying an image. The image displayed by the display device 11a includes light of a first color selected from red, green, and blue. The image displayed by the display device 11b includes light of a second color selected from red, green, and blue, and light of a third color selected from red, green, and blue. The second color is preferably different from the first color, and the third color is preferably different from both the first color and the second color. In the example shown in FIG. 2A , the first color is blue, and the second and third colors are red and green, respectively.

[0037] The colors of light emitted by the elements included in the display devices 11a and 11b are not limited to red, green, and blue. For example, the display devices 11a and 11b may have elements that emit light of colors such as cyan, magenta, yellow, yellow-green, purple, blue-purple, orange, white, infrared, and ultraviolet. Furthermore, the colors of the images displayed by the display devices 11a and 11b are not limited to red, green, and blue. For example, the images may include light of colors such as cyan, magenta, yellow, yellow-green, purple, blue-purple, orange, white, infrared, and ultraviolet.

[0038] The display device 11a can be described as a display device that displays a single color. In a display device that displays a single color, for example, it is not necessary to create pixels corresponding to different colors, and therefore the manufacturing process can be simplified. Furthermore, since it is not necessary to arrange sub-pixels corresponding to different colors within one pixel, the pixel area can be reduced, and high-definition display devices can be realized. Furthermore, since it is not necessary to arrange multiple sub-pixels within one pixel, the pixel aperture ratio can be increased. Increasing the aperture ratio may reduce the power consumption of the display device 11a. Furthermore, increasing the aperture ratio may reduce the brightness per area, and thereby extend the life of the display device 11a.

[0039] The image displayed by the display device 11a and the image displayed by the display device 11b are incident on the user's eye 20 via the lens 12 and are viewed. The image displayed by the display device 11a and the image displayed by the display device 11b are preferably the same size when incident on the user's eye 20. Furthermore, the image displayed by the display device 11a and the image displayed by the display device 11b are preferably viewed as images of the same size in the user's eye 20. Furthermore, the image displayed by the display device 11a and the image displayed by the display device 11b are preferably overlapping to form a single image and are then incident on the user's eye 20. Furthermore, the image displayed by the display device 11a and the image displayed by the display device 11b are preferably viewed as overlapping images in the user's eye 20.

[0040] An electronic device of one embodiment of the present invention includes a plurality of display devices, and by displaying images displayed by the plurality of display devices in an overlapping manner, a higher-resolution image can be provided than an image displayed by a single display device.

[0041] Furthermore, an electronic device according to one embodiment of the present invention includes a plurality of display devices and displays an image in which images displayed by the plurality of display devices are superimposed on each other. This simplifies the manufacturing process of the display device compared to a case in which an image with the same pixel density is displayed by only one display device. This can increase the yield of the electronic device and reduce the manufacturing cost of the electronic device.

[0042] The electronic device 10 can display images of different colors on the display devices 11a and 11b, and can superimpose the image displayed by the display device 11a and the image displayed by the display device 11b. For example, a full-color image can be displayed by superimposing the image displayed by the display device 11a and the image displayed by the display device 11b. The electronic device 10 has a circuit that provides image data to the display devices 11a and 11b. The circuit that provides image data to the display devices will be described in detail below. The image data that the circuit provides to the display devices does not have to be composed of three-color gradation values, but may be composed of two or less colors or four or more colors.

[0043] In an electronic device of one embodiment of the present invention, image data includes, for example, a gradation value representing the luminance of red light (red gradation value), a gradation value representing the luminance of green light (green gradation value), and a gradation value representing the luminance of blue light (blue gradation value). In the electronic device 10 shown in FIG. 2A , for example, the blue gradation value is provided to the display device 11a, and the red gradation value and the green gradation value are provided to the display device 11b. The image data is data representing a display image.

[0044] 2B shows an example of an electronic device in which the display device 11a has a display element that emits green (G) light, and the display device 11b includes a display element that emits red (R) light and a display element that emits blue (B) light. The image displayed by the display device 11a shown in FIG. 2B includes green (G) light, and the image displayed by the display device 11b includes red (R) light and blue (B) light. In the electronic device 10 shown in FIG. 2B, for example, a green gradation value is provided to the display device 11a, and a red gradation value and a blue gradation value are provided to the display device 11b.

[0045] The display device 11a has a plurality of pixels arranged in a matrix, each of which has a sub-pixel corresponding to a first color, while the display device 11b has a plurality of pixels arranged in a matrix, each of which has a sub-pixel corresponding to a second color and a sub-pixel corresponding to a third color.

[0046] For example, the number of subpixels in a pixel of the display device 11a is smaller than the number of subpixels in a pixel of the display device 11b. When the pixel density of the display device 11a and the pixel density of the display device 11b are the same, the area of ​​the subpixels in the pixel of the display device 11a can be larger than the area of ​​the subpixels in the pixel of the display device 11b.

[0047] Alternatively, the area of ​​each sub-pixel of a pixel of the display device 11a can be the same as the area of ​​each sub-pixel of a pixel of the display device 11b. In this case, since the number of sub-pixels of the pixel of the display device 11a is small, the area of ​​each pixel of the display device 11a can be made smaller than the area of ​​each pixel of the display device 11b. This allows the pixel density of the display device 11a to be higher than the pixel density of the display device 11b.

[0048] In the case where the image data includes image data corresponding to red, image data corresponding to green, and image data corresponding to blue, the resolution of the image data corresponding to any one of the colors may be higher than the resolution of the image data corresponding to the other colors. Note that the image data may include image data corresponding to white in addition to red, green, and blue.

[0049] For example, by increasing the number of pixels for colors with high luminosity, it is possible to increase the definition of colors with high luminosity in images displayed by the electronic device 10 .

[0050] The colors represented by the image data are not limited to red, green, blue, and white, but may be cyan, magenta, yellow, yellow-green, purple, blue-purple, orange, infrared, ultraviolet, and the like.

[0051] The display device 11a and the display device 11b each have a display unit. It is preferable that the display units of the display device 11a and the display device 11b have the same size. By making the display units the same size, the configuration of the optical system of the electronic device 10 can be simplified. For example, the number of components used in the optical system can be reduced. The display unit of the display device has, for example, a plurality of pixels arranged in a matrix. Alternatively, it can be expressed as the display device having a plurality of pixels, and the plurality of pixels being arranged in a matrix in the display unit. Alternatively, it can be expressed as the display device having a plurality of pixels, and the plurality of pixels being arranged in a matrix to form the display unit.

[0052] Furthermore, the display units of the display devices 11a and 11b may be different in size. When the display units of the two display devices are different in size, the optical system of the electronic device 10 is configured so that the images displayed by the two display devices overlap when incident on the user's eye 20.

[0053] It is preferable that the display devices 11a and 11b have the same screen aspect ratio, type of display element, power supply voltage, and drive frequency (also called frame frequency). It is also preferable that the display devices 11a and 11b have the same types of elements, such as transistors and capacitors, in their pixel circuits. In particular, the display devices 11a and 11b may be manufactured by the same manufacturer, in the same manufacturing factory, and on the same manufacturing line, thereby reducing the manufacturing cost of the electronic device 10.

[0054] Furthermore, by making the types of display elements, transistor configurations, and capacitance element configurations used in display device 11a and display device 11b equal, the differences in characteristics (color tone, brightness, color reproducibility, response speed, etc.) between display device 11a and display device 11b can be reduced, making it easier to make corrections to align the characteristics compared to using different types of display elements, transistors with different configurations, and capacitance elements with different configurations.

[0055] The display device 11a and the display device 11b may be display devices having the same arrangement of wiring, terminals, drivers (drive circuits), etc., or may be display devices having different arrangements of one or more of these.

[0056] The higher the pixel density of the display device 11a and the display device 11b, the more preferable it is.

[0057] The pixel density of the display device 11a can be, for example, 1000 ppi to 20000 ppi, preferably 2000 ppi to 15000 ppi, more preferably 3000 ppi to 10000 ppi, even more preferably 4000 ppi to 9000 ppi, and even more preferably 5000 ppi to 8000 ppi.

[0058] The pixel density of display device 11a can be the same as the pixel density of display device 11b.

[0059] Alternatively, the pixel density of the display device 11a can be higher than the pixel density of the display device 11b. For example, the pixel density of the display device 11a can be 1.5 times or more, preferably 1.5 times or more and 6 times or less, of the pixel density of the display device 11b. More specifically, for example, the pixel density of the display device 11a can be twice the pixel density of the display device 11b. Alternatively, for example, the pixel density of the display device 11a can be four times the pixel density of the display device 11b. Note that the pixel density of some regions of the display device 11a may be higher than that of the display device 11b, and the pixel density of other regions may be the same as that of the display device 11b.

[0060] The pixel density of the display device 11b may be lower than that of the display device 11a in only one of the horizontal direction (direction along rows) or the vertical direction (direction along columns). For example, the pixel density of the display device 11b may be 2 / 3 or less, or between 1 / 6 and 2 / 3, specifically 0.5 or 0.25 times, of the pixel density of the display device 11a in the horizontal direction.

[0061] The pixel density of the sub-pixels corresponding to the first color of the display device 11a can be the same as the pixel density of the sub-pixels corresponding to the second color of the display device 11b, and the pixel density of the sub-pixels corresponding to the first color of the display device 11a can be the same as the pixel density of the sub-pixels corresponding to the third color of the display device 11b.

[0062] Alternatively, the pixel density of the sub-pixels corresponding to the first color of the display device 11a can be higher than the pixel density of the sub-pixels corresponding to the second color of the display device 11b. For example, the pixel density of the sub-pixels corresponding to the first color of the display device 11a can be set to 1.5 times or more, preferably 1.5 times or more and 6 times or less, and more specifically, for example, 2 times or 4 times the pixel density of the sub-pixels corresponding to the second color of the display device 11b.

[0063] Alternatively, the pixel density of the sub-pixels corresponding to the first color of the display device 11a can be higher than the pixel density of the sub-pixels corresponding to the third color of the display device 11b. For example, the pixel density of the sub-pixels corresponding to the first color of the display device 11a can be set to 1.5 times or more, preferably 1.5 times or more and 6 times or less, and more specifically, for example, 2 times or 4 times the pixel density of the sub-pixels corresponding to the third color of the display device 11b.

[0064] The larger the size of the display unit of the display devices 11a and 11b, the thinner the lens 12 can be, and the smaller the image distortion caused by the lens can be. For example, the diagonal size of the display unit of the display devices 11a and 11b is preferably 0.3 inches or more, or 0.5 inches or more, preferably 0.7 inches or more, more preferably 1 inch or more, and even more preferably 1.3 inches or more, and is preferably 2 inches or less, or 1.7 inches or less. Specifically, a size of 1.5 inches or thereabouts is preferable.

[0065] It is preferable that the diagonal size of the display unit of the display device 11a and the display device 11b is smaller than the diameter of the lens 12. For example, it is preferable that the diagonal size of the display unit of the display device 11a or the display device 11b is 90% or less, preferably 80% or less, and more preferably 70% or less of the diameter of the lens 12. This reduces distortion of the image seen through the lens 12, thereby enhancing the sense of immersion. If the diagonal size of the display unit of the display device 11a or the display device 11b is larger than the diameter of the lens 12, there is a risk that part of the display unit will fall out of the field of view.

[0066] The pixel density and size of the display unit of the display device 11a and the display device 11b are not limited to those described above. For example, if high resolution is not required, a display device with a pixel density of less than 1000 ppi or a display device with a size exceeding 2 inches may be used.

[0067] The lens 12 is a lens located on the side of the user's eye 20 and can also be called an eyepiece. It is preferable to use a convex lens as the lens 12.

[0068] The half mirror 14 is an optical element that is both reflective and transmissive to visible light. For example, a thin metal film formed on a transparent substrate such as glass, quartz, or resin, or a dielectric multilayer film can be used. It is preferable to use a half mirror 14 with a transmittance / reflectance ratio of 1:1. The half mirror 14 is not limited to a half mirror, and other optical elements that utilize properties such as light reflection, refraction, polarization, diffraction, or scattering can also be used as long as they can achieve the function of combining two images. The half mirror 14 has the function of combining two images. For this reason, the half mirror 14 is sometimes called a combiner.

[0069] 1A, the trajectory of light (image) emitted by the display device 11a is shown by a dotted line. The image on the display device 11a is reflected by the half mirror 14, passes through the lens 12, and reaches the user's eye 20. When viewed from the user's perspective, the image displayed on the display device 11a through the lens 12 appears enlarged.

[0070] 1B, the trajectory of light emitted by the display device 11b is shown by a dotted line. The image on the display device 11b passes through the half mirror 14 and reaches the lens 12. When viewed by the user, the image displayed on the display device 11b through the lens 12 appears enlarged.

[0071] The image displayed on the display device 11a and the image displayed on the display device 11b are combined by a half mirror 14. When the display devices 11a and 11b are displayed simultaneously, the user can see through the lens 12 an image in which the image from the display device 11a and the image from the display device 11b are superimposed on each other.

[0072] Next, a more specific configuration of the electronic device 10 will be described. Fig. 2A is a schematic diagram of the electronic device 10. Fig. 2A shows a schematic diagram when viewed from a direction perpendicular to the optical axis of the lens 12.

[0073] 2A, the display device 11b is provided on the optical axis of the lens 12. The half mirror 14 is provided at an angle of 45° with respect to the optical axis of the lens 12, and the display device 11a is disposed at an angle of 45° with respect to the reflective surface of the half mirror 14. However, the angles of the half mirror 14 and the like are not limited to this.

[0074] The focal point of the lens 12 on the side of the user's eye 20 is designated as focal point f1a. Here, an example is shown in which the user's eye 20 is located at focal point f1a.

[0075] It is preferable to position the display device 11 a so that the distance along the path from the display surface of the display device 11 a through the reflecting surface of the half mirror 14 to the center of the lens 12 is shorter than the focal length of the lens 12 .

[0076] Light (shown by a dashed line) emitted from the display surface of the display device 11a is reflected by the half mirror 14 and reaches the lens 12. The light is condensed by the lens 12 and reaches the user's eye 20. The image displayed on the display device 11a appears magnified to the user through the lens 12. Here, the image seen by the user's eye 20 is vertically or horizontally inverted by the half mirror 14 relative to the image displayed on the display unit of the display device 11a. For this reason, it is preferable to display an image that has been vertically or horizontally inverted in advance on the display device 11a.

[0077] Light (shown by a dashed line) emitted from the display surface of the display device 11b passes through the half mirror 14 and reaches the lens 12. The light is condensed by the lens 12 and reaches the user's eye 20. The image displayed on the display device 11b appears magnified through the lens 12 to the user.

[0078] The positions of the display devices 11a and 11b may also be interchanged. Fig. 3A shows a configuration in which the positions of the display devices 11a and 11b are interchanged in Fig. 2A. Fig. 3B shows a configuration in which the positions of the display devices 11a and 11b are interchanged in Fig. 2B.

[0079] 4A and 4B show perspective views of the electronic device 10. Fig. 4A is a perspective view showing the front, top, and left side of the electronic device 10, and Fig. 4B is a perspective view showing the back, bottom, and right side of the electronic device 10. The electronic device 10 is a so-called goggle-type head-mounted display (HMD) that can be worn on the head.

[0080] The electronic device 10 can be used as an electronic device for VR. A user wearing the electronic device 10 can view three-dimensional images using parallax, with different images on the left and right.

[0081] The electronic device 10 has a housing 15 and a wearing device 42. The wearing device 42 has a function of fixing the housing 15 to the head.

[0082] Cameras 49R and 49L are provided on the surface of the housing 15. By displaying images captured by the cameras 49R and 49L in real time, the user can grasp the external situation even while wearing the electronic device 10. In addition, a video see-through function can be realized. By using two or more cameras, three-dimensional images can be created using parallax.

[0083] The electronic device 10 has two lenses 12. The lens 12 for the right eye is referred to as lens 12R, and the lens 12 for the left eye is referred to as lens 12L. The electronic device 10 also has two display devices 11a and 11b. The display devices 11a and 11b for displaying images for the right eye are referred to as display devices 11aR and 11bR, respectively. The display devices 11a and 11b for displaying images for the left eye are referred to as display devices 11aL and 11bL, respectively.

[0084] On the user's side of the housing 15, a lens 12R functioning as an eyepiece for the right eye and a lens 12L functioning as an eyepiece for the left eye are provided in the portion located in front of the user's eyes. Furthermore, inside the housing 15, display devices 11aR and 11bR for displaying images for the right eye, and display devices 11aL and 11bL for displaying images for the left eye are provided. Note that, because the various optical systems exemplified above can be applied to the optical system, components such as half mirrors and lenses are omitted here.

[0085] Since a shift in the relative positions of the display devices 11aR and 11bR would distort the image, it is preferable that they be fixed to the same frame to prevent their relative positions from shifting due to, for example, an impact. The same applies to the display devices 11aL and 11bL. On the other hand, it is preferable that the display devices 11aR and 11aL are configured to move up and down, forward and backward, and left and right, respectively, to match the positions of the user's left and right eyes. For this reason, the display devices 11aR and 11aL may be configured to be fixed to different frames.

[0086] An input terminal and an output terminal may also be provided on the surface of the housing 15. The input terminal can be connected to a cable for supplying a video signal from a video output device or the like, or for supplying power for charging a battery provided within the housing 15. The output terminal functions as an audio output terminal, for example, and can be connected to earphones, headphones, or the like. Note that if the configuration is such that audio data can be output via wireless communication, or if audio is output from an external video output device, the audio output terminal need not be provided.

[0087] The housing 15 may also include a wireless communication module, a storage module, and the like. The wireless communication module performs wireless communication, and the content to be viewed can be downloaded and stored in the storage module. This allows the user to view the downloaded content offline at any time.

[0088] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0089] In this embodiment, a structural example of a display device that can be applied to an electronic device of one embodiment of the present invention will be described. A display device exemplified below can be applied to the display device 11a, the display device 11b, or the like in Embodiment 1.

[0090] One embodiment of the present invention is a display device having a light-emitting element (also referred to as a light-emitting device). The display device has two or more pixels that emit light of different colors. Each pixel has a light-emitting element. Each light-emitting element has a pair of electrodes and an EL layer therebetween. The light-emitting element is preferably an organic EL element (organic electroluminescent element). Two or more light-emitting elements that emit light of different colors each have an EL layer containing a different light-emitting material (also referred to as a light-emitting substance). For example, a full-color display device can be realized by having three types of light-emitting elements that emit red (R), green (G), or blue (B) light, respectively.

[0091] When fabricating a display device having multiple light-emitting elements that emit different colors of light, it is necessary to form at least one layer containing a light-emitting material (light-emitting layer) in an island shape. When fabricating a partial or entire EL layer, a method of forming island-shaped organic films by vapor deposition using a shadow mask such as a metal mask is known. However, this method can cause deviations in the shape and position of the island-shaped organic films from the design due to various factors such as the accuracy of the metal mask, misalignment between the metal mask and the substrate, deflection of the metal mask, and spreading of the contours of the deposited film due to vapor scattering, making it difficult to achieve high-definition and high-aperture display devices. Furthermore, during vapor deposition, the contours of the layer can become blurred, resulting in thinning of the edges. In other words, the thickness of the island-shaped light-emitting layer can vary depending on the location. Furthermore, when fabricating large, high-resolution, or high-definition display devices, there is a concern that low dimensional accuracy of the metal mask and deformation due to heat, etc., can reduce manufacturing yield. Therefore, measures have been taken to artificially increase the resolution (also known as pixel density) by adopting special pixel arrangements such as a pentile array.

[0092] In this specification, the term "island-like" refers to a state in which two or more layers formed using the same material in the same process are physically separated. For example, an island-like light-emitting layer refers to a state in which the light-emitting layer is physically separated from an adjacent light-emitting layer.

[0093] In one embodiment of the present invention, an EL layer is processed into a fine pattern by photolithography without using a shadow mask such as a fine metal mask (FMM). This makes it possible to realize a display device with high definition and a large aperture ratio, which have been difficult to achieve until now. Furthermore, since different EL layers can be formed separately, a display device with extremely vivid images, high contrast, and high display quality can be realized. Note that, for example, the EL layer may be processed into a fine pattern using both a metal mask and photolithography.

[0094] Furthermore, the EL layer can be partially or entirely separated physically. This can suppress leakage current between adjacent light-emitting elements through a layer shared between the light-emitting elements (also referred to as a common layer). This can prevent unintended light emission due to crosstalk, thereby realizing a display device with extremely high contrast. In particular, a display device with high current efficiency at low luminance can be realized.

[0095] One embodiment of the present invention can also be a display device that combines a white-emitting light-emitting element and a color filter. In this case, light-emitting elements provided in pixels (subpixels) that emit light of different colors can have the same configuration, and all layers can be common layers. Furthermore, part or all of each EL layer can be separated by photolithography. This suppresses leakage current through the common layer, thereby achieving a display device with high contrast. In particular, in an element having a tandem structure in which multiple light-emitting layers are stacked via a highly conductive intermediate layer, leakage current through the intermediate layer can be effectively prevented, thereby achieving a display device that combines high brightness, high definition, and high contrast.

[0096] When the EL layer is processed by photolithography, a portion of the light-emitting layer may be exposed, which may cause deterioration. Therefore, it is preferable to provide an insulating layer that covers at least the side surfaces of the island-shaped light-emitting layer. The insulating layer may also be configured to cover a portion of the top surface of the island-shaped EL layer. The insulating layer is preferably made of a material that has barrier properties against water and oxygen. For example, an inorganic insulating film that is less likely to diffuse water or oxygen can be used. This suppresses deterioration of the EL layer, thereby achieving a highly reliable display device.

[0097] Furthermore, there is a region (recess) between two adjacent light-emitting elements where the EL layer of either light-emitting element is not provided. When a common electrode, or a common electrode and a common layer, is formed to cover the recess, a phenomenon in which the common electrode is separated by a step at the edge of the EL layer (also called a step discontinuity) may occur, resulting in insulation of the common electrode on the EL layer. Therefore, it is preferable to use a configuration in which the local step located between two adjacent light-emitting elements is filled with a resin layer functioning as a planarization film (also called LFP: Local Filling Planarization). The resin layer functions as a planarization film. This suppresses step discontinuity of the common layer or common electrode, thereby achieving a highly reliable display device.

[0098] A more specific example of the structure of the display device of one embodiment of the present invention will be described below with reference to the drawings.

[0099] [Configuration Example 1] The top surface shape of a subpixel included in a display device can have various shapes such as a polygon, an ellipse, a circle, and the like. The top surface shape of a subpixel included in a display device may have rounded corners. The top surface shape of a subpixel illustrated in the drawings in this embodiment corresponds to the top surface shape of a light-emitting region, for example.

[0100] 5A is a schematic top view of a display device 100a according to one embodiment of the present invention. The display device 100a is a display device that displays a single color and has light-emitting elements that emit a first color arranged in a matrix over a substrate. In the example shown in FIG. 5A, the display device 100a includes a plurality of pixels 110 over a substrate, and each pixel 110 includes a light-emitting element 110B (sub-pixel 110B) that emits blue light.

[0101] FIG. 5B is a schematic top view of a display device 100b according to one embodiment of the present invention. The display device 100b includes a light-emitting element that exhibits a second color and a light-emitting element that exhibits a third color over a substrate. The light-emitting elements that exhibit the second color and the light-emitting elements that exhibit the third color are arranged in a matrix. Although not shown in FIG. 5B , the display device 100b may also include a light-emitting element that exhibits a fourth color. In the example shown in FIG. 5B , the display device 100b includes a plurality of pixels 110 over a substrate. Each pixel 110 includes a red light-emitting element 110R (sub-pixel 110R) and a green light-emitting element 110G (sub-pixel 110G). In an image displayed by the electronic device according to one embodiment of the present invention, the sub-pixels 110R and 110G of the display device 100b overlap with the sub-pixel 110B of the display device 100a. Therefore, in an image displayed on an electronic device, for example, the pixel 110 shown in FIG. 5A and the pixel 110 shown in FIG. 5B overlap each other.

[0102] 5A and 5B, the symbols R, G, and B are assigned within the light-emitting region of each light-emitting element to easily distinguish between the light-emitting elements. While Figures 5A and 5B show an example in which the display device 100a has a plurality of light-emitting elements that emit blue light, and the display device 100b has a plurality of light-emitting elements that emit red light and a plurality of light-emitting elements that emit green light, the combination of the colors of the light-emitting elements of the display device 100a and the light-emitting elements of the display device 100b is not limited to this. For example, the display device 100a may have a plurality of light-emitting elements that emit green light, and the display device 100b may have a plurality of light-emitting elements that emit red light and a plurality of light-emitting elements that emit blue light.

[0103] The display device 100a can be applied as appropriate to the display device 11a or the display device 11b shown in the above-described embodiments. The display device 100b can be applied as appropriate to the display device 11a or the display device 11b shown in the above-described embodiments. For example, the display device 100a can be applied to the display device that displays a monochrome image out of the display device 11a or the display device 11b, and the display device 100b can be applied to the display device that does not use the display device 100a out of the display device 11a or the display device 11b.

[0104] 5B shows a so-called stripe arrangement in which light-emitting elements of the same color are arranged in one direction. Note that the arrangement method of the light-emitting elements is not limited to this, and arrangement methods such as an S-stripe arrangement, a delta arrangement, a Bayer arrangement, a zigzag arrangement, or a diamond arrangement may also be used.

[0105] As the light-emitting element 110R, the light-emitting element 110G, and the light-emitting element 110B, for example, an OLED (organic light-emitting diode) or a QLED (quantum-dot light-emitting diode) is preferably used. Examples of the light-emitting substance contained in the light-emitting element include a substance that emits fluorescence (fluorescent material), a substance that emits phosphorescence (phosphorescent material), and a substance that exhibits thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) material). As the light-emitting substance contained in the light-emitting element, not only organic compounds but also inorganic compounds (such as quantum dot materials) can be used.

[0106] 5A and 5B also show a connection electrode 111C that is electrically connected to a common electrode of the light-emitting element (common electrode 113, described later). The connection electrode 111C is given a potential (e.g., an anode potential or a cathode potential) to be supplied to the common electrode 113. The connection electrode 111C is provided outside the display area where the light-emitting elements 110R and the like are arranged. Note that although the same reference numerals are used for the connection electrodes 111C in the display device 100a and the display device 100b, the connection electrodes 111C in each display device are not a continuous film, although they have, for example, the same material and similar properties.

[0107] The connection electrode 111C can be provided along the periphery of the display area. For example, it may be provided along one side of the periphery of the display area, or it may be provided over two or more sides of the periphery of the display area. That is, when the top surface shape of the display area is rectangular, the top surface shape of the connection electrode 111C can be a strip shape (rectangle), an L-shape, a U-shape (square bracket shape), a square shape, or the like.

[0108] Note that the display device 100a is a display device that displays a single color, and therefore does not require sub-pixels corresponding to different colors to be arranged within a single pixel. This allows the area of ​​the sub-pixels to be increased, thereby increasing the light-emitting area of ​​the light-emitting element. For example, the sub-pixel 110B shown in FIG. 5A can be configured to be wider than the sub-pixels 110R and 110G. This allows the sub-pixel 110B to have an area more than twice that of the sub-pixels 110R and 110G shown in FIG. 5B. Furthermore, in FIGS. 5A and 5B, the area of ​​the pixel 110 is approximately the same in the display device 100a and the display device 100b. Note that FIGS. 5A and 5B are depicted to approximately the same scale.

[0109] In a plan view, it is preferable that the horizontal and vertical widths of the pixels of the display device are approximately the same. By making the horizontal and vertical widths approximately the same, the horizontal and vertical resolutions of the display device can be made approximately the same, thereby improving display quality.

[0110] 5A shows an example in which the top surface shape of the subpixels of the display device 100a is approximately square. Note that in FIG. 5A, the top surface shape of the subpixels is not limited to a square, but it is preferable that the horizontal width and vertical width of the top surface shape of the subpixels are approximately the same.

[0111] 5A , the area of ​​the sub-pixel 110B corresponding to blue light emission can be increased. Therefore, the light-emitting area of ​​the light-emitting element included in the sub-pixel 110B can be increased. This allows, for example, the luminance per area of ​​the light-emitting element corresponding to blue light emission to be reduced, thereby extending the life of the display element and the display device 100a.

[0112] 6B shows an example of a display device 100b in which the arrangement of subpixels 110R and 110G is different from that shown in FIG. 5B . The display device 100b shown in FIG. 6B has a configuration in which two subpixels displaying the same color are adjacent to each other in the horizontal direction. In adjacent subpixels of the same color, for example, the organic layer 112 (here, organic layer 112R and organic layer 112G) can be made continuous, eliminating the need to process the organic layer 112 into an island shape in each subpixel. This allows for a larger processing dimension for the organic layer 112, making it easier to fabricate the display device 100b.

[0113] The display device 100a and the display device 100b have two pixels 110 (hereinafter referred to as pixel 110(1) and pixel 110(2)) with different sub-pixel arrangements. In the display device 100b, the pixel 110(1) and the pixel 110(2) have a configuration that is inverted horizontally.

[0114] 7A and 7B also show an example in which the areas of the subpixels 110R, 110G, and 110B are approximately the same. In the example shown in FIGS. 7A and 7B, the display device 100a has two subpixels 110B arranged horizontally in the pixel 110. In FIGS. 7A and 7B, for example, the same image signal may be applied to the two subpixels 110B of the pixel 110. Alternatively, different signals may be applied to the two subpixels 110B of the pixel 110, so that the horizontal definition of the display device 100a is higher than that of the display device 100b.

[0115] 5A, 5B, 6A, 6B, 7A, and 7B, the colors displayed by the subpixels of the display device 100a and the colors displayed by the subpixels of the display device 100b are not limited to those described above. For example, the subpixel 110G may be used in place of the subpixel 110B of the display device 100a, and the subpixel 110B may be used in place of the subpixel 110G of the display device 100b.

[0116] 8A and 8B show an example in which the display device 100a has a subpixel 110G, and the display device 100b has a subpixel 110R and a subpixel 110B. In FIGS. 8A and 8B, the area of ​​one subpixel is approximately square. Green has high luminosity. By reducing the pixel pitch of the display device 100a, the resolution of the display unit can be increased for colors with high luminosity. By increasing the resolution of colors with high luminosity, a user viewing an image displayed by the electronic device 10 can perceive the image as having high resolution.

[0117] 8B shows an example in which the subpixels 110R and 110B of the display device 100b are arranged in a lattice pattern. That is, in the display device 100b, the subpixels 110R and 110B are arranged alternately in both the row direction and the column direction. The arrangement of the subpixels 110R and 110B shown in FIG. 8B is sometimes referred to as a houndstooth arrangement.

[0118] In Fig. 8A , pixel 110 of display device 100a has one sub-pixel 110G. When display device 100a of Fig. 8A is superimposed on display device 100b of Fig. 8B , which region of display device 100b becomes pixel 110 varies depending on how pixel 110 of display device 100a is superimposed. Variations in superimposition of pixel 110 of display device 100a of Fig. 8A with sub-pixel of display device 100b of Fig. 8B are shown in Figs. 9A , 9B , 9C , and 10 .

[0119] 9A , 9B , 9C , and 10 , the subpixel 110G of the display device 100a coincides with the pixel 110. Each of these figures shows how the subpixel of the display device 100a (here, the subpixel 110G) and the subpixel of the display device 100b (here, the subpixel 110R and the subpixel 110B) overlap in an image formed by combining an image displayed by the display device 100a and an image displayed by the display device 100b. Note that in FIGS. 9A , 9B , 9C , and 10 , the area of ​​the subpixel 110G is depicted as being larger than the areas of the subpixels 110R and 110B to make the overlap of the subpixels easier to see. However, the areas of the subpixels 110G, 110R, and 110B may be substantially the same or different from each other.

[0120] FIG. 9A shows an example in which the subpixel 110G of the display device 100a overlaps with the subpixel 110R or the subpixel 110B of the display device 100b.

[0121] 9B shows an example in which approximately half the area of ​​the subpixel 110G of the display device 100a overlaps with both the subpixel 110R and the subpixel 110B of the display device 100b. In Fig. 9B, the subpixel 110G overlaps with the subpixels 110R and 110B adjacent to it on the left and right in a top view. In the example shown in Fig. 9B, all of the subpixels 110G of the display device 100a overlap with both the subpixels 110R and 110B of the display device 100b in the synthesized image, which has the advantage of making it easier to obtain a natural image.

[0122] The configuration in which all the subpixels 110G of the display device 100a overlap both the subpixels 110R and 110B of the display device 100b is not limited to that shown in FIG. 9B, and configurations such as those shown in FIGS. 9C and 10 are also possible.

[0123] FIG. 9C shows an example in which the subpixel 110G overlaps with the subpixels 110R and 110B that are adjacent to it in the vertical direction when viewed from above.

[0124] 10, one of the subpixels of the display device 100a is arranged so as to overlap with four subpixels arranged in two rows and two columns in the display device 100b. Alternatively, it can be expressed as one of the subpixels of the display device 100b is arranged so as to overlap with four subpixels arranged in two rows and two columns in the display device 100a.

[0125] Fig. 11A is a schematic cross-sectional view corresponding to dashed line A1-A2 in Fig. 5A. Fig. 11B is a schematic cross-sectional view corresponding to dashed line B1-B2 in Fig. 5B. Fig. 11C is a schematic cross-sectional view applicable to both dashed line A3-A4 in Fig. 5A and dashed line B3-B4 in Fig. 5B. Fig. 11A shows a schematic cross-sectional view of light-emitting element 110B, Fig. 11B shows schematic cross-sectional views of light-emitting element 110R and light-emitting element 110G, and Fig. 11C shows a schematic cross-sectional view of connection portion 140 where connection electrode 111C and common electrode 113 are connected.

[0126] The display device 100a shown in FIG. 11A has a light-emitting element 110B on a layer 101. The light-emitting element 110B has a pixel electrode 111B, an organic layer 112B, a common layer 114, and a common electrode 113. The display device 100b shown in FIG. 11B has a light-emitting element 110R and a light-emitting element 110G on a layer 101. The light-emitting element 110R has a pixel electrode 111R, an organic layer 112R, a common layer 114, and a common electrode 113. The light-emitting element 110G has a pixel electrode 111G, an organic layer 112G, a common layer 114, and a common electrode 113. In FIG. 11B, the common layer 114 and the common electrode 113 are provided in common to the light-emitting element 110R and the light-emitting element 110G.

[0127] The display device 100a and the display device 100b are assigned the same symbols for components such as the common layer 114 and the common electrode 113, but the components with the same symbols have, for example, similar materials and similar properties, but are not a continuous film.

[0128] Note that Figure 11A shows an example in which the organic layer 112B of the light-emitting element 110B is formed in an island shape for each light-emitting element, but as shown in Figure 11D, the organic layer 112B may not be formed in an island shape but may be provided across multiple light-emitting elements 110B.

[0129] The organic layer 112B of the light-emitting element 110B contains a light-emitting organic compound that emits at least blue light. The organic layer 112R of the light-emitting element 110R contains a light-emitting organic compound that emits at least red light. The organic layer 112G of the light-emitting element 110G contains a light-emitting organic compound that emits at least green light. The organic layer 112B, the organic layer 112R, and the organic layer 112G can also be referred to as EL layers, and each contains at least a layer (light-emitting layer) that contains a light-emitting organic compound.

[0130] Hereinafter, when describing matters common to organic layer 112B, organic layer 112R, and organic layer 112G, they may be referred to as organic layer 112. Similarly, when describing matters common to components distinguished by alphabets, such as pixel electrode 111B, pixel electrode 111R, and pixel electrode 111G, they may be described using symbols without the alphabets.

[0131] The layer 101 can be, for example, a variety of substrates.

[0132] As the various substrates, semiconductor substrates can be used. Specifically, as the substrate, a single crystal semiconductor substrate made of silicon, silicon carbide, or the like, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, or an SOI substrate can be used. Furthermore, as the substrate, an insulating substrate such as a glass substrate, a quartz substrate, a sapphire substrate, or a plastic substrate can also be used. Furthermore, the substrate may be flexible.

[0133] It is preferable to use a circuit substrate having a transistor, a wiring, or the like as the layer 101. For example, a substrate provided with a circuit for driving each light-emitting element (also referred to as a pixel circuit) or a semiconductor circuit that functions as a driver circuit for driving the pixel circuit can be used as the layer 101.

[0134] In particular, it is preferable to use the semiconductor substrate or the insulating substrate on which a semiconductor circuit including a semiconductor element such as a transistor is formed as the layer 101. The semiconductor circuit preferably constitutes, for example, a pixel circuit, a gate line driving circuit (gate driver), a source line driving circuit (source driver), or the like. In addition to the above, an arithmetic circuit, a memory circuit, or the like may also be configured.

[0135] The organic layer 112 and the common layer 114 may each independently include one or more of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. For example, the organic layer 112 may have a stacked structure of a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer from the pixel electrode 111 side, and the common layer 114 may have an electron injection layer.

[0136] The pixel electrode 111B, pixel electrode 111R, and pixel electrode 111G are provided for each light-emitting element. The common electrode 113 and common layer 114 are provided as a continuous layer common to each light-emitting element. A conductive film transmissive to visible light is used for either the pixel electrode or the common electrode 113, and a conductive film reflective to visible light is used for the other. By making each pixel electrode transmissive and the common electrode 113 reflective, a bottom-emission display device can be obtained. Conversely, by making each pixel electrode reflective and the common electrode 113 transmissive, a top-emission display device can be obtained. Note that by making both the pixel electrodes and the common electrode 113 transmissive, a dual-emission display device can also be obtained.

[0137] 11A and 11D, a protective layer 121 is provided on the common electrode 113 to cover the light-emitting element 110B. In addition, in Fig. 11B, a protective layer 121 is provided to cover the light-emitting element 110R and the light-emitting element 110G. The protective layer 121 has a function of preventing impurities such as water from diffusing from above into each light-emitting element.

[0138] The edge of the pixel electrode 111 preferably has a tapered shape. When the edge of the pixel electrode 111 has a tapered shape, the organic layer 112 provided along the edge of the pixel electrode 111 can have a shape having an inclined portion. By tapering the edge of the pixel electrode 111, the coverage of the organic layer 112 provided over the edge of the pixel electrode 111 can be improved. Furthermore, by tapering the side surface of the pixel electrode 111, foreign matter (for example, also referred to as dust or particles) during the manufacturing process can be easily removed by a process such as cleaning, which is preferable.

[0139] In this specification and the like, the term "tapered shape" refers to a shape in which at least a part of a side surface of a structure is inclined with respect to a substrate surface. For example, it is preferable that the structure has a region in which the angle between the inclined side surface and the substrate surface (also referred to as the taper angle) is less than 90°.

[0140] The organic layer 112 is processed into an island shape by photolithography. As a result, the angle between the top surface and the side surface of the organic layer 112 at its edge is close to 90 degrees. On the other hand, an organic film formed using FMM or the like tends to become gradually thinner closer to the edge. For example, the top surface is formed in a sloped shape over a range of 1 μm to 10 μm, making it difficult to distinguish between the top surface and the side surface.

[0141] Between two adjacent light emitting elements, an insulating layer 125, a resin layer 126, and a layer 128 are provided.

[0142] Between two adjacent light-emitting elements, the side surfaces of the organic layers 112 face each other with the resin layer 126 sandwiched therebetween. The resin layer 126 is located between the two adjacent light-emitting elements and is provided so as to fill the region between the two organic layers 112. In addition, in Figures 11A and 11B, the resin layer 126 is provided so as to cover the ends of each organic layer 112. The resin layer 126 has a smooth, convex upper surface, and a common layer 114 and a common electrode 113 are provided covering the upper surface of the resin layer 126.

[0143] The resin layer 126 functions as a planarization film that fills in a step located between two adjacent light-emitting elements. By providing the resin layer 126, it is possible to prevent a phenomenon (also called step disconnection) in which the common electrode 113 is divided by a step at the end of the organic layer 112, and the common electrode on the organic layer 112 is isolated. The resin layer 126 can also be called LFP (Local Filling Planarization).

[0144] An insulating layer containing an organic material can be suitably used as the resin layer 126. For example, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin, precursors of these resins, etc. can be used as the resin layer 126. Alternatively, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used as the resin layer 126.

[0145] Furthermore, a photosensitive resin can be used as the resin layer 126. A photoresist can be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0146] The resin layer 126 may contain a material that absorbs visible light. For example, the resin layer 126 itself may be made of a material that absorbs visible light, or the resin layer 126 may contain a pigment that absorbs visible light. For example, the resin layer 126 may be a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light, or a resin that contains carbon black as a pigment and functions as a black matrix.

[0147] The insulating layer 125 is provided in contact with the side surface of the organic layer 112. The insulating layer 125 is also provided to cover the upper end portion of the organic layer 112. A portion of the insulating layer 125 is provided in contact with the upper surface of the layer 101.

[0148] The insulating layer 125 is located between the resin layer 126 and the organic layer 112, and functions as a protective film to prevent the resin layer 126 from contacting the organic layer 112. If the organic layer 112 and the resin layer 126 come into contact with each other, the organic layer 112 may be dissolved by an organic solvent or the like used when forming the resin layer 126. Therefore, by providing the insulating layer 125 between the organic layer 112 and the resin layer 126, it is possible to protect the side surfaces of the organic layer 112.

[0149] The insulating layer 125 can be an insulating layer containing an inorganic material. For example, an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film can be used for the insulating layer 125. The insulating layer 125 may have a single-layer structure or a stacked-layer structure. Examples of oxide insulating films include a silicon oxide film, an aluminum oxide film, a magnesium oxide film, an indium gallium zinc oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, and a tantalum oxide film. Examples of nitride insulating films include a silicon nitride film and an aluminum nitride film. Examples of oxynitride insulating films include a silicon oxynitride film and an aluminum oxynitride film. Examples of nitride oxide insulating films include a silicon nitride oxide film and an aluminum nitride oxide film. In particular, by using an inorganic insulating film such as a metal oxide film, an aluminum oxide film, or a silicon oxide film formed by an ALD method as the insulating layer 125, an insulating layer 125 with few pinholes and excellent protection of the EL layer can be formed.

[0150] In this specification and elsewhere, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0151] The insulating layer 125 can be formed by a sputtering method, a CVD method, a PLD method, an ALD method, or the like. The insulating layer 125 is preferably formed by an ALD method because it has good coverage.

[0152] Furthermore, a reflective film (e.g., a metal film containing one or more selected from silver, palladium, copper, titanium, aluminum, etc.) may be provided between the insulating layer 125 and the resin layer 126, so that the light emitted from the light-emitting layer is reflected by the reflective film, thereby improving the light extraction efficiency.

[0153] The layer 128 is a remaining portion of a protective layer (also referred to as a mask layer or a sacrificial layer) for protecting the organic layer 112 during etching of the organic layer 112. The layer 128 can be made of a material that can be used for the insulating layer 125. In particular, it is preferable to use the same material for the layer 128 and the insulating layer 125 because a common processing device or the like can be used for both.

[0154] In particular, inorganic insulating films such as metal oxide films such as aluminum oxide films and hafnium oxide films, or silicon oxide films formed by the ALD method have few pinholes and therefore have an excellent function of protecting the EL layer, and can be suitably used for the insulating layer 125 and the layer 128.

[0155] The protective layer 121 may have, for example, a single-layer structure or a stacked structure including at least an inorganic insulating film. Examples of the inorganic insulating film include oxide films or nitride films such as a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, an aluminum oxynitride film, and a hafnium oxide film. Alternatively, the protective layer 121 may be made of a semiconductor material or a conductive material such as indium gallium oxide, indium zinc oxide, indium tin oxide, or indium gallium zinc oxide.

[0156] The protective layer 121 may also be a laminated film of an inorganic insulating film and an organic insulating film. For example, a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films is preferable. Furthermore, it is preferable that the organic insulating film functions as a planarizing film. This allows the upper surface of the organic insulating film to be flat, improving the coverage of the inorganic insulating film thereon and enhancing the barrier properties. Furthermore, since the upper surface of the protective layer 121 is flat, when a structure (e.g., a color filter, a touch sensor electrode, a lens array, etc.) is provided above the protective layer 121, the influence of uneven shapes caused by the structure below can be reduced, which is preferable.

[0157] 11C shows a connection portion 140 where the connection electrode 111C and the common electrode 113 are electrically connected. In the connection portion 140, an opening is provided in the insulating layer 125 and the resin layer 126 above the connection electrode 111C. The connection electrode 111C and the common electrode 113 are electrically connected in the opening.

[0158] 11C shows a connection portion 140 where the connection electrode 111C and the common electrode 113 are electrically connected, but the common electrode 113 may be provided on the connection electrode 111C via the common layer 114. In particular, when a carrier injection layer is used for the common layer 114, the electrical resistivity of the material used for the common layer 114 is sufficiently low and the common layer 114 can be formed thin, so there are many cases where no problem occurs even if the common layer 114 is located at the connection portion 140. This allows the common electrode 113 and the common layer 114 to be formed using the same shielding mask, thereby reducing manufacturing costs.

[0159] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0160] Embodiment 3 In this embodiment, an example of an electronic device according to one embodiment of the present invention will be described.

[0161] 12A and 12B show an example in which a display device 41 is applied instead of the display device 11b in the electronic device 10 shown in FIGS. 4A and 4B.

[0162] In the electronic device 10, the display device 41 can be used in place of the display device 11a or the display device 11b. For example, the display device 41 can be used in place of the display device 11b shown in Figures 2A, 2B, and 4, or the display device 11a shown in Figures 3A and 3B. The display device 41 for displaying an image for the right eye is referred to as the display device 41R, and the display device 41 for displaying an image for the left eye is referred to as the display device 41L.

[0163] The display device 41 includes a display unit 37 and a drive circuit. An example of the configuration of the display unit 37 applicable to the display device 41 is shown using FIG. 13A . The display unit 37 includes a display unit 37a having a high pixel density and a display unit 37b having a lower pixel density than the display unit 37a. The display unit 37b may be a peripheral area of ​​the display unit 37a. The display device 41R and the display device 41L include the display unit 37a and the display unit 37b, respectively. The pixel density of the display unit 37b may be less than 1000 ppi, preferably between 50 ppi and 1000 ppi, and more preferably between 100 ppi and 800 ppi.

[0164] FIG. 13A is a plan view showing an example of the configuration of the display unit 37.

[0165] The display unit 37 has a display unit 37a and a display unit 37b. The display unit 37a may be the center of the display unit 37 or a region in its vicinity, and the display unit 37b may be the peripheral region of the display unit 37a. In other words, the display unit 37b is provided so as to surround the display unit 37a in a plan view. This allows the user of the electronic device 10 to view the image displayed on the display unit 37a in the center of the field of view or in its vicinity, and view the image displayed on the display unit 37b in the peripheral field of view.

[0166] The display unit 37 can also be expressed as a configuration in which a low-resolution display unit is added to the periphery of the display unit of the display device 11a or the display unit of the display device 11b of the electronic device 10.

[0167] The center of the display unit 37 may be located on the display unit 37b instead of the display unit 37a. Furthermore, the display unit 37b does not have to surround the entire display unit 37a. For example, if the shape of the display unit 37a is rectangular, the display unit 37b does not have to surround all four sides of the display unit 37a. For example, the display unit 37b may be configured to surround three of the four sides of the display unit 37a. Alternatively, the display unit 37b may be configured to surround two of the four sides of the display unit 37a entirely and to surround the remaining two sides partially.

[0168] The pixels 27a and 27b are provided with pixel circuits that control the driving of the light-emitting elements. The pixel circuits include transistors. This allows the display units 37a and 37b to be driven by an active matrix method.

[0169] As shown in FIG. 13A , the pixel density of the display unit 37a is higher than that of the display unit 37b. For example, the area occupied by each pixel 27a in the display unit 37a is smaller than the area occupied by each pixel 27b in the display unit 37b. Furthermore, the distance between the pixels 27a is shorter than the distance between the pixels 27b. As described above, the display unit 37a displays an image viewed in the center of the user's visual field of the electronic device 10 and its vicinity, while the display unit 37b displays an image viewed in the peripheral visual field. Here, humans distinguish images in the center of the visual field and its vicinity in detail, while distinguishing images outside of that in a more general manner. For example, humans distinguish images in the central and effective visual fields in detail, while distinguishing images in the peripheral visual field in a more general manner. Therefore, even if the pixel density of display unit 37b is made lower than the pixel density of display unit 37a and the resolution of the image displayed on display unit 37b is made lower than the resolution of the image displayed on display unit 37a, the user of electronic device 10 will not notice a decrease in image quality, and will not notice a grainy appearance, for example. On the other hand, by lowering the pixel density of display unit 37b, for example, it is possible to increase the area occupied by the entire display unit 37. As described above, by making the pixel density of display unit 37b lower than the pixel density of display unit 37a, it is possible to increase the area occupied by display unit 37 without causing the user of the electronic device to notice a decrease in image quality, compared to when the pixel density is uniform across the entire display unit 37.

[0170] The display device 41 can be used in place of the display device 11b in the electronic device 10 shown in Figures 2A and 2B. In this case, for example, a full-color display can be realized by superimposing an image displayed on the display unit 37a of the display device 41 and an image displayed on the display unit of the display device 11a.

[0171] FIG. 13B shows an example in which the electronic device 10 shown in FIG. 2A uses the display device 41 instead of the display device 11b. In FIG. 13B, the image displayed by the display device 11a and the image displayed by the display unit 37a of the display device 41 are superimposed and viewed by the user through the lens 12. In FIG. 11B, the image displayed by the display unit 37b of the display device 41 is viewed by the user through the lens 12 as an image of the peripheral region of the image displayed by the display device 11a and the image displayed by the display unit 37a. It is preferable that the image displayed by the display unit 37b and the image displayed by the display device 11a do not overlap in the image viewed by the user through the lens 12. It is also possible that the image displayed by the display device 11a and the image displayed by the display unit 37b overlap in the vicinity of the periphery of the image displayed by the display device 11a.

[0172] 3A and 3B, the display device 41 can be used in place of the display device 11a. In this case, for example, a full-color display can be realized by superimposing an image displayed by the display unit 37a of the display device 41 and an image displayed by the display unit of the display device 11b.

[0173] The pixel 27a will be described below.

[0174] When using display device 41 in place of display device 11b, the display unit of display device 11b can be applied to display unit 37a, and pixel 27a has an element that displays one color selected from red, green, and blue, and an element that displays another color different from the one color.

[0175] When the display device 41 is used in place of the display device 11b shown in Fig. 2A, the pixel 27a has an element that displays red and an element that displays green. When the display device 41 is used in place of the display device 11b shown in Fig. 2B, the pixel 27a has an element that displays red and an element that displays blue.

[0176] When the display device 41 is used in place of the display device 11a, the display unit of the display device 11a can be applied to the display unit 37a, and the pixel 27a has an element that displays one color selected from red, green, and blue.

[0177] When the display device 41 is used in place of the display device 11a shown in Fig. 3A, the pixel 27a has an element that displays blue. When the display device 41 is used in place of the display device 11a shown in Fig. 3B, the pixel 27a has an element that displays green.

[0178] Next, the pixel 27b will be described.

[0179] The pixel 27b may have, for example, an element that displays red, an element that displays green, and an element that displays blue. The display unit 37b may have, for example, multiple display elements, each displaying a different color, thereby achieving a full-color display. The colors displayed by the display elements of the pixel 27b are not limited to red, green, and blue. For example, a combination of elements that display light of colors such as red, green, blue, cyan, magenta, yellow, yellow-green, purple, blue-purple, orange, white, infrared, and ultraviolet may be used. While it is preferable for the display unit 37b to achieve a full-color display, a monochrome display unit may also be used as the display unit 37b. In this case, for example, the pixel 27b may have one of the elements that display light of colors such as red, green, blue, cyan, magenta, yellow, yellow-green, purple, blue-purple, orange, white, infrared, and ultraviolet.

[0180] The display unit 37a and the display unit 37b can be provided on the same substrate.

[0181] FIG. 14 is a cross-sectional view showing an example of the configuration of a display device 41 taken along the dashed dotted line A1-A2 in FIG. 13, including the display units 37a and 37b.

[0182] The display device 41 includes a substrate 611, a layer 612 on the substrate 611, and a substrate 613 on the layer 612, and the display unit 37 is provided on the layer 612. In addition, for example, a driver circuit for driving the display device 41 is provided on the layer 612. Since the driver circuit includes, for example, a transistor, the layer 612 includes a transistor.

[0183] The display unit 37a can display an image by emitting the light 34a. The display unit 37b can display an image by emitting the light 34b. The light 34a and the light 34b are transmitted through the substrate 613.

[0184] Display unit 37a is provided so as to have an area that does not overlap with display unit 37b. Note that a portion of display unit 37a may overlap with display unit 37b. Specifically, an edge of display unit 37a may overlap with display unit 37b, and an edge of display unit 37b may overlap with display unit 37a. This configuration prevents an area where display unit 37 is not provided from being formed between display unit 37a and display unit 37b. This prevents a user of electronic device 10 from visually recognizing the boundary between display unit 37a and display unit 37b. Even if a portion of display unit 37a overlaps with display unit 37b, display unit 37b can be said to be provided so as to surround display unit 37a as long as the area of ​​display unit 37b that does not overlap with display unit 37a surrounds display unit 37a.

[0185] Furthermore, the display unit 37a and the display unit 37b may be formed on different substrates and then superimposed on each other, as shown in FIGS. 15A to 17B.

[0186] Fig. 15A is a cross-sectional view showing a configuration example between dashed dotted lines A1-A2 in Fig. 13A, and is a cross-sectional view showing a configuration example of a display device including display unit 37. As shown in Fig. 15A, display unit 37a is included in display device 41a, and display unit 37b is included in display device 41b.

[0187] The display device 41a has a substrate 611a, a layer 612a on the substrate 611a, and a substrate 613a on the layer 612a, and the display unit 37a is provided on the layer 612a. The display device 41b has a substrate 611b, a layer 612b on the substrate 611b, and a substrate 613b on the layer 612b, and the display unit 37b is provided on the layer 612b. For example, a driver circuit for driving the display device 41a is provided on the layer 612a, and a driver circuit for driving the display device 41b is provided on the layer 612b. These driver circuits include, for example, transistors, and therefore the layers 612a and 612b each include a transistor.

[0188] The display device 41b is provided on the display device 41a. The display device 41a overlaps with the display device 41b. Specifically, for example, the substrate 613a overlaps with the substrate 611b. For example, the substrate 613a has an area in contact with the substrate 611b, and the display device 41a is fixed below the display device 41b. For example, the first housing is attached to the display device 41a, and the second housing is attached to the display device 41b, and the first housing and the second housing are engaged, thereby fixing the display device 41a below the display device 41b. Furthermore, the display device 41b has an area that does not overlap with the display device 41a. Specifically, for example, the substrate 611b has an area that does not overlap with the substrate 613a.

[0189] The display unit 37a can display an image by emitting light 34a. The display unit 37b can display an image by emitting light 34b. The light 34a passes through the substrate 613a, the substrate 611b, the layer 612b, and the substrate 613b. The light 34b passes through the substrate 613b. As described above, the substrate 613a, the substrate 611b, the layer 612b, and the substrate 613b are configured to pass the light 34a. The substrate 613b is configured to pass the light 34b. Here, the substrate 611a can be configured to block the light 34a and the light 34b. Therefore, the substrate 611a can be configured to block visible light, for example. On the other hand, the substrates 611b, 613a, and 613b are configured to pass visible light.

[0190] The display unit 37a is provided so as to have an area that does not overlap with the display unit 37b. This allows the light 34a incident on the display device 41b to be extracted to the outside of the display device 41b even if the display unit 37b does not transmit the light 34a or even if the transmittance of the light 34a in the display unit 37b is lower than the transmittance of the light 34a in the area of ​​the layer 612b where the display unit 37b is not provided. Therefore, a user of the electronic device 10 having the display units 41a and 41b can view the image displayed on the display unit 37a.

[0191] Note that a portion of display unit 37a may overlap display unit 37b. Specifically, an edge of display unit 37a may overlap display unit 37b, and an edge of display unit 37b may overlap display unit 37a. This configuration prevents an area where display unit 37 is not provided from being formed between display unit 37a and display unit 37b. This prevents a user of electronic device 10 from visually recognizing the boundary between display unit 37a and display unit 37b. Even if a portion of display unit 37a overlaps display unit 37b, as long as the area of ​​display unit 37b that does not overlap with display unit 37a surrounds display unit 37a, it can be said that display unit 37b is provided to surround display unit 37a.

[0192] As described above, in the electronic device 10, the display device 41a is arranged to overlap the display device 41b, and the display unit 37b of the display device 41b is arranged to surround the display unit 37a of the display device 41a. This reduces the loss of light 34a compared to, for example, a case where the display devices 41a and 41b are not overlapped and the images displayed by the display units 37a and 37b are combined using an optical combiner such as a half mirror. Furthermore, the loss of light 34b may also be reduced in some cases. Therefore, the electronic device 10 can be a low-power electronic device. Furthermore, a user of the electronic device 10 can view a high-brightness image.

[0193] Materials that can be applied to the substrate 611, the substrate 611a, the substrate 611b, the substrate 613, the substrate 613a, or the substrate 613b will be described below.

[0194] The substrate 611 can be configured to be opaque to visible light. Alternatively, the substrate 611 can be configured to be transparent to visible light. The substrate 611 can also be a substrate that can be used as the substrate 611a, the substrate 611b, and the substrate 18 described below.

[0195] The substrate 613 can be configured to transmit visible light. The substrate 613 can also be a substrate that can be used as a substrate 613a, a substrate 613b, or a substrate 16 described below.

[0196] As described above, the substrate 611a may be configured to be opaque to visible light, for example. Therefore, the substrate 611a may be, for example, a semiconductor substrate. Specifically, the substrate 611a may be a single-crystal semiconductor substrate made of silicon, silicon carbide, or the like, a polycrystalline semiconductor substrate, a compound semiconductor substrate made of silicon germanium, or an SOI substrate.

[0197] As described above, the substrates 613a, 611b, and 613b are configured to transmit, for example, visible light. Therefore, for example, a glass substrate, a quartz substrate, a sapphire substrate, or a plastic substrate is used as the substrate 613a, 611b, and 613b. Note that a glass substrate, a quartz substrate, a sapphire substrate, or a plastic substrate can also be used as the substrate 611a as an insulating substrate.

[0198] The thickness of substrate 611a, substrate 613a, substrate 611b, and substrate 613b can be 50 μm or more and 2 mm or less, preferably 50 μm or more and 1 mm or less, more preferably 50 μm or more and 500 μm or less, and even more preferably 50 μm or more and 300 μm or less.

[0199] Various optical members can be disposed on the surface of the substrate 613a opposite to the display unit 37a and on the surface of the substrate 613b opposite to the display unit 37b. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light-collecting film.

[0200] FIG. 15B is a modified example of the configuration shown in FIG. 15A, and differs from the configuration shown in FIG. 15A in that a display device 41b has a substrate 18 instead of the substrate 611b and a substrate 16 instead of the substrate 613b.

[0201] The substrate 18 and the substrate 16 are flexible. This allows the display device 41b shown in Fig. 15B to be flexible. Therefore, the display device 41b shown in Fig. 15B can be called a flexible display.

[0202] A flexible substrate can be thinner than a non-flexible substrate. Therefore, for example, the thickness of the substrate 18 and the substrate 16 can be thinner than the thickness of the substrate 611a. As described above, by using a flexible display as the display device 41b, the difference in height between the display unit 37b and the display unit 37a, for example, relative to the surface of the substrate 611a, can be reduced. This reduces the difference between the distance from the user's eyes of the electronic device 10 to the display unit 37a and the distance from the user's eyes of the electronic device 10 to the display unit 37b, thereby preventing blurring of either or both of the images displayed on the display unit 37a and the display unit 37b. Therefore, the user of the electronic device 10 can view high-quality images.

[0203] Furthermore, for example, by reducing the difference in height between the display unit 37b and the display unit 37a with respect to the surface of the substrate 611a, it is possible to prevent the light 34a emitted by the display unit 37a of the display device 41a from being incident on the display unit 37b. For example, if the electrode of the light-emitting element of the display unit 37b reflects visible light, the light 34a incident on the display unit 37b is reflected by the electrode and is not extracted to the outside of the display device 41b. Therefore, by preventing the light 34a from being incident on the display unit 37b, it is possible to increase the light extraction efficiency of the display device 41a.

[0204] In the display device shown in FIG. 15B, the substrate 613b shown in FIG. 15A may be provided instead of the substrate 16. That is, among the substrates included in the display device 41b, only the substrate provided between the display units 37a and 37b may be flexible. Also, the substrate 613a included in the display device 41a may be flexible. For example, the thickness of the substrate 611b shown in FIG. 15A may be thinner than the thickness of the substrate 611a. That is, the substrate included in the display device 41b may be an inflexible substrate, but the thickness of the substrate may be thinner than the thickness of the substrate 611a. Also, the substrate 613a may be an inflexible substrate, but the thickness of the substrate 613a may be thinner than the thickness of the substrate 611a.

[0205] Examples of flexible substrates that can be used include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resins, acrylic resins, polyimide resins, polymethyl methacrylate resins, polycarbonate (PC) resins, polyethersulfone (PES) resins, polyamide resins (nylon, aramid, etc.), polysiloxane resins, cycloolefin resins, polystyrene resins, polyamideimide resins, polyurethane resins, polyvinyl chloride resins, polyvinylidene chloride resins, polypropylene resins, polytetrafluoroethylene (PTFE) resins, ABS resins, and cellulose nanofibers. Glass having a thickness sufficient to provide flexibility may also be used. By using the above-listed materials for the substrate, the substrate can transmit visible light.

[0206] The thickness of the flexible substrate is set within a range that achieves both flexibility and mechanical strength. For example, the thickness of the flexible substrate can be set to 1 μm or more and 300 μm or less, more preferably 10 μm or more and 300 μm or less, more preferably 10 μm or more and 100 μm or less, and even more preferably 10 μm or more and 50 μm or less. Note that, for example, the thickness of the substrate 611b shown in FIG. 15A may be set within this thickness range. In other words, the substrate of the display device 41b may be a non-flexible substrate, and the thickness of the substrate may be set within this thickness range.

[0207] In the configurations shown below, the substrate 611b may be replaced with the substrate 18, and the substrate 613b may be replaced with the substrate 16.

[0208] Fig. 15C is a modified example of the configuration shown in Fig. 15B, and differs from the configuration shown in Fig. 15B in that the display device 41a does not have a substrate 613a. For example, the various optical members described above can be provided directly on the layer 612a, and the display device 41b can be provided thereon.

[0209] By omitting the substrate 613a, for example, the difference in height between the display unit 37b and the display unit 37a relative to the surface of the substrate 611a can be reduced. This allows the user of the electronic device 10 to view high-quality images. Furthermore, the light 34a is prevented from being incident on the display unit 37b, thereby improving the light extraction efficiency of the display device 41a. In the display device 41b shown in FIG. 15C , the substrate 611b may be provided instead of the substrate 18, and the substrate 613b may be provided instead of the substrate 16. In other words, even if the display device 41a does not include the substrate 613a, the substrate provided in the display device 41b does not need to be flexible.

[0210] Fig. 16A is a modified example of the configuration shown in Fig. 15A, and differs from the configuration shown in Fig. 15A in that an adhesive layer 614 is provided between the substrate 613a and the substrate 611b. The adhesive layer 614 transmits light 34a. Therefore, the adhesive layer 614 transmits, for example, visible light.

[0211] By bonding the display devices 41a and 41b together with the adhesive layer 614, it is possible to prevent a gap from being formed between the display devices 41a and 41b. This prevents the light 34a emitted from the display device 41a from being reflected or refracted by the gap. Therefore, the display device 41a can display a high-quality image.

[0212] For the above reasons, it is preferable to provide the adhesive layer 614 in the region of the substrate 613a that does not overlap with the display unit 37b. On the other hand, it is not necessary to provide the adhesive layer 614 in the region of the substrate 613a that overlaps with the display unit 37b.

[0213] The adhesive layer 614 can be made of various curable adhesives, such as a photo-curable adhesive (e.g., an ultraviolet-curable adhesive), a reactive curable adhesive, a heat-curable adhesive, or an anaerobic adhesive. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. In particular, a material with low moisture permeability, such as epoxy resin, is preferable. A two-component resin may also be used. Alternatively, an adhesive sheet, for example, may also be used.

[0214] Figure 16B is a modified example of the configuration shown in Figure 15A, and differs from the configuration shown in Figure 15A in that a substrate 613b is provided on the display device 41a, a layer 612b including a display unit 37b is provided on the substrate 613b, and a substrate 611b is provided on the layer 612b.

[0215] For example, in the display device 41b shown in FIG. 15A, the drive circuit is provided below the display unit 37b. On the other hand, in the display device 41b shown in FIG. 16B, the drive circuit is provided above the display unit 37b. Also, for example, in the display device 41b shown in FIG. 15A, light 34b emitted from the display unit 37b passes through the substrate 613b. On the other hand, in the display device 41b shown in FIG. 16B, light 34b passes through the substrate 611b. For example, the display device 41b shown in FIG. 15A is a top-emission display device, and the display device 41b shown in FIG. 16B is a bottom-emission display device.

[0216] Fig. 16C is a modified example of the configuration shown in Fig. 15A, and differs from the configuration shown in Fig. 15A in that the display device 41a is provided on the display device 41b. As described above, the substrate 611a may be configured to be opaque to visible light, for example. Therefore, the display unit 37b may be provided so as to overlap the entire display unit 37a, for example. Furthermore, the substrate 611b may be configured to be opaque to visible light, for example.

[0217] FIG. 17A is a modified example of the configuration shown in FIG. 15A , differing from the configuration shown in FIG. 15A in that a display unit 37c is provided on layer 612b of display device 41b. Display unit 37c is provided so as to overlap display unit 37a of display device 41a. In the configuration shown in FIG. 17A , display unit 37 includes display units 37a, 37b, and 37c. Although not shown, display unit 37c has a plurality of pixels arranged, for example, in a matrix. Each pixel has a light-emitting element that emits visible light, and light emitted by the light-emitting element is emitted from the pixel as light 34c, thereby displaying an image on display unit 37c. Here, the pixel density of display unit 37c can be lower than that of display unit 37a and equivalent to that of display unit 37b. Therefore, the resolution of the image displayed on the display unit 37c can be lower than the resolution of the image displayed on the display unit 37a and can be made equal to the resolution of the image displayed on the display unit 37b.

[0218] The light 34c passes through the substrate 613b. The pixel has a pixel circuit that controls the driving of the light emitting element. As described above, the pixel circuit has a transistor.

[0219] In the configuration shown in FIG. 17A , light 34a emitted from the display unit 37a is incident on the display unit 37c. Therefore, the display unit 37c is configured to transmit the light 34a, specifically, to have a higher transmittance for the light 34a than the display unit 37b. For example, the display unit 37c is configured to transmit visible light, specifically, to have a higher transmittance for visible light than the display unit 37b. For example, an electrode of a light-emitting element provided in the display unit 37c is configured to transmit the light 34a. Furthermore, a layer included in a transistor included in a pixel circuit provided in the display unit 37c is configured to transmit the light 34a. Furthermore, if the pixel circuit has, for example, a capacitor, a layer constituting the capacitor is configured to transmit the light 34a. Furthermore, for example, wiring provided in the display unit 37c is also configured to transmit the light 34a. As described above, the display unit 37c can transmit the light 34a.

[0220] 17A , the user of the electronic device 10 can view the image displayed on the display unit 37c of the display device 41b superimposed on the image displayed on the display unit 37a of the display device 41a. Here, since the resolution of the image that the display unit 37c can display is lower than the resolution of the image that the display unit 37a can display, it is preferable to display images on the display units 37a and 37c. For example, a mark such as a cursor indicating a point of interest in the image displayed on the display unit 37a can be displayed on the display unit 37c.

[0221] Fig. 17B is a modified example of the configuration shown in Fig. 17A, and differs from the configuration shown in Fig. 17A in that the display unit 37c has an area that does not overlap with the display unit 37a. Note that Fig. 17B shows an example in which the display device 41b does not have the display unit 37b, but the display device 41b may have the display unit 37b. For example, the display unit 37b may be provided in an area that does not overlap with the display device 41a. Note that in the configuration shown in Fig. 17B, the area of ​​the display unit 37c that does not overlap with the display device 41a may transmit light 44, which is external light.

[0222] FIG. 18A is a block diagram showing an example configuration of a display device 41a having a display unit 37a. As described above, the display unit 37a has a plurality of pixels 27a arranged therein, for example, in a matrix. Each pixel 27a has one or more sub-pixels. The display device 41a also has a gate driver circuit 42a and a source driver circuit 43a. Although not shown in FIG. 18A, the gate driver circuit 42a and the source driver circuit 43a are electrically connected to the pixels 27a. The gate driver circuit 42a and the source driver circuit 43a are drive circuits for the display device 41a.

[0223] In the display device 41a, a source driver circuit 43a can write image data to pixels 27a selected by a gate driver circuit 42a. By writing image data to the pixels 27a, the pixels 27a emit light 34a with a brightness corresponding to the image data, thereby displaying an image on a display unit 37a.

[0224] FIG. 18B is a block diagram showing an example configuration of a display device 41b having a display unit 37b. As described above, a plurality of pixels 27b are arranged in the display unit 37b. Here, the display device 41b is provided with an area 38 where the pixels 27b are not arranged, and a display unit 37b is provided to surround the area 38. The area 38 overlaps with the display unit 37a of the display device 41a. Note that when the display device 41b has the configuration shown in FIG. 17A, the display unit 37b is provided in the area 38. When the display device 41b has the configuration shown in FIG. 17B, a display unit 37c is provided in place of the display unit 37b, and a display unit 37c is also provided in the area 38.

[0225] The display device 41b also includes a gate driver circuit 42b and a source driver circuit 43b. Although not shown in Fig. 18B, the gate driver circuit 42b and the source driver circuit 43b are electrically connected to the pixel 27b. The gate driver circuit 42b and the source driver circuit 43b are drive circuits for the display device 41b.

[0226] In the display device 41b, a source driver circuit 43b can write image data to pixels 27b selected by a gate driver circuit 42b. By writing image data to the pixels 27b, the pixels 27b emit light 34b with a brightness corresponding to the image data, thereby displaying an image on a display unit 37b.

[0227] Fig. 19 is a perspective view showing an example of the configuration of a display device 41a. As shown in Fig. 19, the display device 41a can have a configuration including a layer 40, a layer 50 on the layer 40, and a layer 60 on the layer 50.

[0228] A plurality of pixel circuits 51 are arranged in the layer 50, and a plurality of light-emitting elements 61 are arranged in the layer 60. The pixel circuits 51 and the light-emitting elements 61 are electrically connected to each other to function as pixels 27a. Therefore, the region where the plurality of pixel circuits 51 provided in the layer 50 and the plurality of light-emitting elements 61 provided in the layer 60 overlap functions as a display section 37a.

[0229] The layer 40 is provided with a gate driver circuit 42a and a source driver circuit 43a. By providing the gate driver circuit 42a and the source driver circuit 43a on a different layer from the pixel circuits 51, the gate driver circuit 42a and the source driver circuit 43a can be provided overlapping the display unit 37a. This allows the width of the frame around the display unit 37a to be narrower than when the gate driver circuit 42a and the source driver circuit 43a are provided so as not to overlap the display unit 37a. This allows the area occupied by the display unit 37a to be increased.

[0230] Furthermore, by stacking the pixel circuit 51, the gate driver circuit 42a, and the source driver circuit 43a, the wiring electrically connecting them can be shortened, thereby reducing wiring resistance and parasitic capacitance. This, for example, shortens the time required for charging and discharging the wiring, allowing the display device 41a to be driven at high speed. Furthermore, the power consumption of the display device 41a can be reduced, thereby reducing the power consumption of the electronic device 10.

[0231] The gate driver circuit 42a and the source driver circuit 43a may be provided in the same layer as the pixel circuit 51. In this case, for example, the transistors included in the gate driver circuit 42a and the source driver circuit 43a and the transistors included in the pixel circuit 51 can be formed in the same process. Furthermore, for example, some of the transistors included in the gate driver circuit 42a and some of the transistors included in the source driver circuit 43a may be provided in the layer 50. That is, the gate driver circuit 42a and the source driver circuit 43a may be provided across the layer 40 and the layer 50. Furthermore, one of the gate driver circuit 42a and the source driver circuit 43a may be provided in the layer 40, and the other of the gate driver circuit 42a and the source driver circuit 43a may be provided in the layer 50.

[0232] Note that multiple gate driver circuits 42a and multiple source driver circuits 43a may be provided. For example, the display unit may be divided into several sections, and a gate driver circuit and a source driver circuit may be provided for each section. Furthermore, each gate driver circuit and source driver circuit may be provided so as to overlap with each section of the display unit. Furthermore, each gate driver circuit and source driver circuit may be provided so as to be disposed close to each section of the display unit.

[0233] By providing multiple gate driver circuits 42a, the wiring electrically connecting the pixel circuits 51 and the gate driver circuits 42a can be shortened. Specifically, the maximum wiring length from the pixel circuits 51 to the gate driver circuits 42a can be reduced. Furthermore, by providing multiple source driver circuits 43a, the wiring electrically connecting the pixel circuits 51 and the source driver circuits 43a can be shortened. Specifically, the maximum wiring length from the pixel circuits 51 to the source driver circuits 43a can be reduced. This reduces wiring resistance and parasitic capacitance. This, for example, shortens the time required for charging and discharging the wiring, allowing the display device 41a to be driven at high speed. Furthermore, the power consumption of the display device 41a can be reduced, allowing the power consumption of the electronic device 10 to be reduced. Furthermore, for example, the number of rows of pixel circuits 51 scanned by one gate driver circuit 42a can be reduced, allowing the frame frequency of the display device 41a to be increased.

[0234] Furthermore, the gate driver circuit 42a may have an overlapping area with the source driver circuit 43a. By configuring the gate driver circuit 42a to have an overlapping area with the source driver circuit 43a, the degree of freedom in the layout of the gate driver circuit 42a and the source driver circuit 43a can be increased. On the other hand, by configuring the gate driver circuit 42a and the source driver circuit 43a so that they do not overlap, it is possible to prevent the driving of the gate driver circuit 42a and the driving of the source driver circuit 43a from affecting each other.

[0235] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0236] Embodiment 4 In this embodiment, a display device according to one embodiment of the present invention will be described.

[0237] [Display Module] FIG. 20 shows a perspective view of a display module 280. The display module 280 includes a display device 100A and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100A and may be any of the display devices 100C to 100G described later. The display devices 100A to 100G can be suitably applied to the display device 41a described in Embodiment 1. FIG. 20 shows the substrate 17a, the display portion 37a, and the substrate 13a, which are components of the display device 100A.

[0238] The FPC 290 functions as wiring for supplying data signals, power supply potential, etc. from the outside to the display device 100A. An IC may also be mounted on the FPC 290.

[0239] The substrates shown in the above embodiments can be appropriately referred to for the substrate 17a and the substrate 13a.

[0240] 21 is a cross-sectional view showing an example of the configuration of the display device 100A, specifically, a cross-sectional view showing an example of the configuration of a pixel included in the display device 100A. The display device 100A includes a substrate 301, a light-emitting element 61A, a light-emitting element 61C, a capacitor 240, and a transistor 310.

[0241] The substrate 301 corresponds to the substrate 17a in FIG. 20 . The transistor 310 is a transistor having a channel formation region in the substrate 301. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a pair of low-resistance regions 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The pair of low-resistance regions 312 are regions in which impurities are doped in the substrate 301 and function as a source and a drain. The insulating layer 314 is provided to cover side surfaces of the conductive layer 311.

[0242] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0243] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0244] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located therebetween. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as a dielectric of the capacitor 240.

[0245] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and the drain of the transistor 310 by a plug 275 buried in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0246] An insulating layer 255a is provided to cover the capacitor 240, an insulating layer 255b is provided on the insulating layer 255a, and an insulating layer 255c is provided on the insulating layer 255b. A light-emitting element 61A and a light-emitting element 61C are provided on the insulating layer 255c. The light-emitting element 61A emits light 34aA, and the light-emitting element 61C emits light 34aC.

[0247] An insulator is provided in the region between adjacent light emitting elements 61. For example, in Fig. 21, a protective layer 271 and an insulating layer 278 on the protective layer 271 are provided in this region.

[0248] An EL layer 172A is provided so as to cover the top surface and side surfaces of the conductive layer 171 of the light-emitting element 61A, and an EL layer 172C is provided so as to cover the top surface and side surfaces of the conductive layer 171 of the light-emitting element 61C. A layer 270A is located over the EL layer 172A, and a layer 270C is located over the EL layer 172C. The layers 270A and 270C are formed by leaving behind a part of a protective layer (also referred to as a mask layer or a sacrificial layer) for protecting the EL layers 172A and 172C when the EL layers 172A and 172C are etched.

[0249] The conductive layer 171 is electrically connected to one of the source and drain of the transistor 310 through a plug 256 embedded in the insulating layer 243, the insulating layer 255a, the insulating layer 255b, and the insulating layer 255c, the conductive layer 241 embedded in the insulating layer 254, and a plug 275 embedded in the insulating layer 261. The height of the top surface of the insulating layer 255c and the height of the top surface of the plug 256 are the same or approximately the same. Various conductive materials can be used for the plug.

[0250] A protective layer 273 is provided on the light emitting elements 61A and 61C. A substrate 120 is attached to the protective layer 273 by an adhesive layer 122. The substrate 120 corresponds to the substrate 13a in FIG.

[0251] The light emitting element 61A and the light emitting element 61C may be light emitting elements that emit different colors, or may be light emitting elements that emit the same color.

[0252] The light-emitting element 61A and the light-emitting element 61C can have any of the structures of the light-emitting element 110B, the light-emitting element 110R, and the light-emitting element 110G shown in the above-described embodiments.

[0253] The pixel electrode 111 described in the above embodiment can be applied to the conductive layer 171. The EL layer 172A and the EL layer 172C can refer to any one of the organic layers 112B, 112R, and 112G described in the above embodiment. The common layer 174 can refer to the common layer 114 described in the above embodiment. The conductive layer 173 can refer to the common electrode 113 described in the above embodiment. The protective layer 271 can refer to the insulating layer 125 described in the above embodiment. The insulating layer 278 can refer to the resin layer 126 described in the above embodiment. The layer 270A and the layer 270C can refer to the layer 128 described in the above embodiment.

[0254] A light-shielding layer may be provided on the surface of the substrate 120 facing the adhesive layer 122. Various optical members may be disposed on the outside of the substrate 120. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light-collecting film. The outside of the substrate 120 may also be provided with a surface protection layer such as an anti-static film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses the occurrence of scratches during use, or an impact absorbing layer. For example, a glass layer or a silica layer (SiO ｘ The surface protection layer can be preferably formed of a material such as DLC (diamond-like carbon), aluminum oxide (AlO ｘ ), polyester-based materials, polycarbonate-based materials, etc. may be used for the surface protection layer. It is preferable to use a material with high transmittance to visible light for the surface protection layer. It is also preferable to use a material with high hardness for the surface protection layer.

[0255] When a circularly polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy as a substrate included in the display device. A substrate with high optical isotropy has small birefringence. It can also be said that a substrate with high optical isotropy has a small amount of birefringence.

[0256] The absolute value of the retardation (phase difference) of a substrate having high optical isotropy is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0257] Examples of films with high optical isotropy include triacetyl cellulose (TAC, also known as cellulose triacetate) films, cycloolefin polymer (COP) films, cycloolefin copolymer (COC) films, and acrylic films.

[0258] Furthermore, when a film is used as a substrate, the film may absorb water, which may cause changes in shape, such as wrinkles, in the display device. For this reason, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferably 0.1% or less, and even more preferably 0.01% or less.

[0259] 22 has a configuration in which a transistor 310A and a transistor 310B, each having a channel formed in a semiconductor substrate, are stacked. Note that in the following description of the display device, descriptions of parts that are the same as those of the display device described above may be omitted.

[0260] The display device 100C has a configuration in which a substrate 301B on which a transistor 310B, a capacitor 240, and a light-emitting element 61 are provided and a substrate 301A on which a transistor 310A is provided are bonded together.

[0261] Here, it is preferable to provide an insulating layer 345 on the lower surface of the substrate 301B. It is also preferable to provide an insulating layer 346 on the insulating layer 261 provided on the substrate 301A. The insulating layers 345 and 346 are insulating layers that function as protective layers and can suppress the diffusion of impurities into the substrates 301B and 301A. The insulating layers 345 and 346 can be made of an inorganic insulating film that can be used for the protective layer 273.

[0262] The substrate 301B is provided with a plug 343 that penetrates the substrate 301B and an insulating layer 345. Here, it is preferable to provide an insulating layer 344 to cover the side surface of the plug 343. The insulating layer 344 is an insulating layer that functions as a protective layer and can suppress the diffusion of impurities into the substrate 301B. The insulating layer 344 can be an inorganic insulating film that can be used for the protective layer 273.

[0263] Furthermore, in the substrate 301B, a conductive layer 342 is provided below the insulating layer 345. The conductive layer 342 is preferably provided so as to be embedded in the insulating layer 335. Furthermore, the lower surfaces of the conductive layer 342 and the insulating layer 335 are preferably flattened. Here, the conductive layer 342 is electrically connected to the plug 343.

[0264] On the other hand, in the substrate 301A, a conductive layer 341 is provided on an insulating layer 346. The conductive layer 341 is preferably provided so as to be embedded in the insulating layer 336. In addition, the upper surfaces of the conductive layer 341 and the insulating layer 336 are preferably flattened.

[0265] The substrate 301A and the substrate 301B are electrically connected by bonding the conductive layer 341 and the conductive layer 342. Here, by improving the flatness of the surface formed by the conductive layer 342 and the insulating layer 335 and the surface formed by the conductive layer 341 and the insulating layer 336, the conductive layer 341 and the conductive layer 342 can be favorably bonded to each other.

[0266] It is preferable to use the same conductive material for the conductive layers 341 and 342. For example, a metal film containing an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, or a metal nitride film containing the above elements (e.g., a titanium nitride film, a molybdenum nitride film, or a tungsten nitride film) can be used. In particular, it is preferable to use copper for the conductive layers 341 and 342. This allows for the application of Cu-Cu (copper-copper) direct bonding technology (technology for achieving electrical conductivity by connecting Cu (copper) pads together).

[0267] Display Device 100D The display device 100D shown in FIG. 23 has a configuration in which a conductive layer 341 and a conductive layer 342 are joined via a bump 347.

[0268] 23 , by providing a bump 347 between the conductive layer 341 and the conductive layer 342, the conductive layer 341 and the conductive layer 342 can be electrically connected. The bump 347 can be formed using a conductive material containing, for example, gold (Au), nickel (Ni), indium (In), or tin (Sn). For example, solder may be used as the bump 347. An adhesive layer 348 may be provided between the insulating layer 345 and the insulating layer 346. When the bump 347 is provided, the insulating layer 335 and the insulating layer 336 may not be provided.

[0269] [Display Device 100E] A display device 100E shown in FIG. 24 differs from the display device 100A mainly in the configuration of the transistors.

[0270] The transistor 320 is an OS transistor. The transistor 320 includes a semiconductor layer 321, an insulating layer 323, a conductive layer 324, a pair of conductive layers 325, an insulating layer 326, and a conductive layer 327.

[0271] The substrate 331 corresponds to the substrate 17a in Fig. 20. The substrate 331 may be an insulating substrate or a semiconductor substrate.

[0272] An insulating layer 332 is provided over a substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320 and prevents oxygen from being released from the semiconductor layer 321 toward the insulating layer 332. The insulating layer 332 can be, for example, a film through which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0273] A conductive layer 327 is provided over the insulating layer 332, and an insulating layer 326 is provided to cover the conductive layer 327. The conductive layer 327 functions as a first gate electrode of the transistor 320, and part of the insulating layer 326 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a region of the insulating layer 326 that is in contact with the semiconductor layer 321. The top surface of the insulating layer 326 is preferably planarized.

[0274] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide film having semiconductor properties. A pair of conductive layers 325 is provided over and in contact with the semiconductor layer 321 and functions as a source electrode and a drain electrode.

[0275] An insulating layer 328 is provided to cover top surfaces and side surfaces of the pair of conductive layers 325 and side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided over the insulating layer 328. The insulating layer 328 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 264 or the like into the semiconductor layer 321 and prevents oxygen from being released from the semiconductor layer 321. The insulating layer 328 can be an insulating film similar to the insulating layer 332.

[0276] Openings reaching the semiconductor layer 321 are provided in the insulating layer 328 and the insulating layer 264. Inside the openings, an insulating layer 323 in contact with side surfaces of the insulating layer 264, the insulating layer 328, and the conductive layer 325 and a top surface of the semiconductor layer 321, and a conductive layer 324 on the insulating layer 323 are buried. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0277] The top surface of the conductive layer 324, the top surface of the insulating layer 323, and the top surface of the insulating layer 264 are planarized so that their heights are the same or approximately the same, and an insulating layer 329 and an insulating layer 265 are provided to cover them.

[0278] The insulating layer 264 and the insulating layer 265 function as interlayer insulating layers. The insulating layer 329 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 265 or the like to the transistor 320. The insulating layer 329 can be formed using an insulating film similar to the insulating layer 328 and the insulating layer 332.

[0279] The plug 274 electrically connected to one of the pair of conductive layers 325 is provided to be embedded in the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328. Here, the plug 274 preferably includes a conductive layer 274a covering the side surfaces of the openings of the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328 and part of the top surface of the conductive layer 325, and a conductive layer 274b in contact with the top surface of the conductive layer 274a. In this case, the conductive layer 274a is preferably made of a conductive material through which hydrogen and oxygen do not easily diffuse.

[0280] [Display Device 100F] A display device 100F illustrated in FIG. 25 has a stacked structure of a transistor 320A and a transistor 320B each including an oxide semiconductor as a semiconductor in which a channel is formed.

[0281] The transistor 320A, the transistor 320B, and the surrounding configurations thereof can be referred to the display device 100E.

[0282] Although two transistors including an oxide semiconductor are stacked here, the present invention is not limited to this structure, and for example, three or more transistors may be stacked.

[0283] [Display Device 100G] A display device 100G illustrated in FIG. 26 has a stacked structure of a transistor 310 in which a channel is formed in a substrate 301 and a transistor 320 in which a channel is formed and a semiconductor layer containing metal oxide.

[0284] An insulating layer 261 is provided to cover the transistor 310, and a conductive layer 251 is provided over the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided over the insulating layer 262. The conductive layers 251 and 252 each function as wirings. An insulating layer 263 and an insulating layer 332 are provided to cover the conductive layer 252, and the transistor 320 is provided over the insulating layer 332. An insulating layer 265 is provided to cover the transistor 320, and a capacitor 240 is provided over the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0285] The transistor 320 can be used as a transistor that forms a pixel circuit. The transistor 310 can be used as a transistor that forms a pixel circuit or a driver circuit (such as a gate driver circuit or a source driver circuit) that drives the pixel circuit. The transistors 310 and 320 can be used as transistors that form various circuits such as an arithmetic circuit or a memory circuit.

[0286] With this configuration, not only the pixel circuit but also, for example, a driver circuit can be formed directly under the light-emitting element, which makes it possible to reduce the size of the display device compared to when the driver circuit is provided around the periphery of the display area.

[0287] 27 shows a perspective view of the display device 100H. The display device 100H can be suitably applied to the display device 41b shown in the third embodiment.

[0288] The display device 100H has a configuration in which the substrate 13b and the substrate 17b are bonded together. In Fig. 27, the substrate 13b is indicated by a dashed line. The substrates shown in the previous embodiments can be appropriately referred to for the substrate 17b and the substrate 13b.

[0289] The display device 100H has a display unit 37b, a connection unit 140, a circuit 164, wiring 165, etc. Fig. 27 shows an example in which an IC 176 and an FPC 177 are mounted on the display device 100H. Therefore, the configuration shown in Fig. 27 can also be called a display module having the display device 100H, an IC (integrated circuit), and an FPC. Here, a display device with a connector such as an FPC attached to its substrate, or a display device with an IC mounted on the substrate, is called a display module.

[0290] The display unit 37b is provided so as to surround the region 38. The region 38 is a region where no image is displayed. Here, the display unit 37c shown in Embodiment 1 may be provided in the region 38. Alternatively, the display unit 37c may be provided instead of the display unit 37b, and the display unit 37c may also be provided in the region 38. Furthermore, the display unit 37b may be provided not only outside the region 38 but also within the region 38.

[0291] The connection portion 140 is provided outside the display portion 37b. The connection portion 140 can be provided along one side or multiple sides of the display portion 37b. The connection portion 140 may be single or multiple. Figure 27 shows an example in which the connection portion 140 is provided so as to surround the four sides of the display portion 37b. The connection portion 140 electrically connects the common electrode of the light-emitting element and the conductive layer, and can supply a potential to the common electrode.

[0292] The circuit 164 may be, for example, a gate driver circuit.

[0293] Signals and power can be supplied to the display portion 37b and the circuit 164 through the wiring 165. The signals and power are input to the wiring 165 from the outside through the FPC 177 or from the IC 176.

[0294] 27 shows an example in which an IC 176 is provided on the substrate 17b by a chip-on-glass (COG) method or a chip-on-film (COF) method. The IC 176 may be, for example, an IC having a gate driver circuit or a source driver circuit. The display device 100H and the display module may be configured without an IC. Alternatively, the IC may be mounted on an FPC by a COF method, for example.

[0295] 28A shows an example of a cross section of the display device 100H, in which a part of a region including the FPC 177, a part of the circuit 164, a part of the display portion 107, a part of the connecting portion 140, and a part of a region including an end portion are cut away. Here, the structure of the display portion 107 can be applied to the display portion 37b shown in FIG. 27. When the display portion 37c described in Embodiment 1 is provided in the region 38, the structure of the display portion 107 can be applied to the display portion 37c.

[0296] 28A includes, between substrate 17b and substrate 13b, transistor 201, transistor 205, light-emitting element 63R that emits red light 34bR, light-emitting element 63G that emits green light 34bG, and light-emitting element 63B that emits blue light 34bB. Various optical components can be disposed on the outside of substrate 13b. Examples of optical components include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light-collecting film.

[0297] The light-emitting element 63R has a conductive layer 171, an EL layer 172R on the conductive layer 171, and a conductive layer 173 on the EL layer 172R. The light-emitting element 63G has a conductive layer 171, an EL layer 172G on the conductive layer 171, and a conductive layer 173 on the EL layer 172G. The light-emitting element 63B has a conductive layer 171, an EL layer 172B on the conductive layer 171, and a conductive layer 173 on the EL layer 172B. The EL layer 172R, EL layer 172G, and EL layer 172B can refer to the organic layers 112R, 112G, and 112B, respectively.

[0298] The conductive layer 171 functioning as a pixel electrode included in each of the light-emitting elements 63R, 63G, and 63B is electrically connected to the conductive layer 222b included in the transistor 205 through an opening provided in the insulating layer 214. The conductive layer 171 is provided along the opening in the insulating layer 214. As a result, a recess is provided in the conductive layer 171.

[0299] 28H shows an example in which an insulating layer 272 is provided to cover the end portion of the conductive layer 171. The insulating layer 272 can be provided so as to fill a recess in the conductive layer 171. Note that although FIG. 28H shows a configuration example in which the insulating layer 272 covers the end portion of the conductive layer 171, a configuration in which the end portion of the conductive layer 171 is not covered with an insulating layer may also be used. For example, as a configuration of a light-emitting element, as shown in FIGS. 11A and 11B, a configuration in which the end portion of a conductive layer functioning as a pixel electrode is not covered with an insulating layer, but is covered with an organic layer, and an insulating layer is provided between the organic layers of adjacent light-emitting elements.

[0300] A protective layer 273 is provided on the light-emitting elements 63R, 63G, and 63B. The protective layer 273 and the substrate 13b are bonded via an adhesive layer 142. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light-emitting elements 63R, 63G, and 63B. In FIG. 28A , the space between the substrate 13b and the substrate 17b is filled with the adhesive layer 142, and a solid sealing structure is applied. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), and a hollow sealing structure may be applied. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting elements. Alternatively, the space may be filled with a resin different from the frame-shaped adhesive layer 142.

[0301] 28A shows an example in which the connection portion 140 has a conductive layer 168 obtained by processing the same conductive film as the conductive film that becomes the conductive layer 171. A power supply potential is supplied to the conductive layer 168, and the conductive layer 168 is electrically connected to a conductive layer 173 that functions as a common electrode. Therefore, the power supply potential can be supplied to the conductive layer 173 through the conductive layer 168.

[0302] The display device 100H is a top-emission type. Light emitted from the light-emitting elements is emitted toward the substrate 13b. The conductive layer 171, which functions as a pixel electrode, contains a material that reflects visible light, and the conductive layer 173, which functions as a common electrode, contains a material that transmits visible light.

[0303] The transistor 201 and the transistor 205 are both formed on the substrate 17b and can be manufactured using the same material and in the same process.

[0304] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided in this order over the substrate 17b. A part of the insulating layer 211 functions as a first gate insulating layer of each transistor. A part of the insulating layer 213 functions as a second gate insulating layer of each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 is provided to cover the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0305] At least one insulating layer covering the transistor is preferably made of a material that is resistant to the diffusion of impurities such as water and hydrogen. This allows the insulating layer to function as a barrier layer. With this structure, it is possible to effectively prevent impurities from diffusing into the transistor from the outside, thereby improving the reliability of the display device.

[0306] It is preferable to use an inorganic insulating film for each of the insulating layers 211, 213, and 215. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. Alternatively, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may also be used. Two or more of the above insulating films may be stacked.

[0307] An organic insulating layer is suitable for the insulating layer 214, which functions as a planarization layer. Materials that can be used for the organic insulating layer include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene-based resin, phenolic resin, and precursors of these resins. The insulating layer 214 may also have a laminated structure of an organic insulating layer and an inorganic insulating layer. The outermost layer of the insulating layer 214 preferably functions as an etching protection layer. This can prevent recesses from being formed in the insulating layer 214, for example, during processing of a conductive film that will become the conductive layer 171. Recesses may be formed in the insulating layer 214, for example, during processing of a conductive film that will become the conductive layer 171.

[0308] The transistor 201 and the transistor 205 each include a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a first gate insulating layer, conductive layers 222a and 222b that function as a source and a drain, a semiconductor layer 231, an insulating layer 213 that functions as a second 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.

[0309] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Furthermore, either a top-gate transistor or a bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0310] The transistor 201 and the transistor 205 have a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates may be connected and the same signal may be supplied to drive the transistor. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential for controlling the threshold voltage to one of the two gates and a potential for driving to the other.

[0311] The crystallinity of the semiconductor layer of the transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0312] A semiconductor layer of the transistor preferably contains a metal oxide. That is, an OS transistor is preferably used as a transistor included in the display device of this embodiment.

[0313] Examples of metal oxides that can be used in the semiconductor layer include indium oxide, gallium oxide, and zinc oxide. The metal oxide preferably contains two or three elements selected from indium, element M, and zinc. The element M is one or more elements selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, cobalt, and magnesium. In particular, the element M is preferably one or more elements selected from aluminum, gallium, yttrium, and tin.

[0314] In particular, as the metal oxide used for the semiconductor layer, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO). Alternatively, it is preferable to use an oxide containing indium, tin, and zinc (also referred to as ITZO (registered trademark)). Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), and zinc (Zn) (also referred to as IAZO). Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), gallium (Ga), and zinc (Zn) (also referred to as IAGZO).

[0315] When the metal oxide used in the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. Examples of atomic ratios of metal elements in such an In-M-Zn oxide include a composition of In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:1:1.2 or thereabouts, In:M:Zn=1:3:2 or thereabouts, In:M:Zn=1:3:4 or thereabouts, In:M:Zn=2:1:3 or thereabouts, In:M:Zn=3:1:2 or thereabouts, and In:M:Zn=4:2. :3 or a composition in the vicinity thereof, In:M:Zn = 4:2:4.1 or a composition in the vicinity thereof, In:M:Zn = 5:1:3 or a composition in the vicinity thereof, In:M:Zn = 5:1:6 or a composition in the vicinity thereof, In:M:Zn = 5:1:7 or a composition in the vicinity thereof, In:M:Zn = 5:1:8 or a composition in the vicinity thereof, In:M:Zn = 6:1:6 or a composition in the vicinity thereof, and In:M:Zn = 5:2:5 or a composition in the vicinity thereof. Note that a composition in the vicinity thereof includes a range of ±30% of the desired atomic ratio.

[0316] For example, when describing a composition having an atomic ratio of In:Ga:Zn = 4:2:3 or thereabout, this includes a case where, when In is taken as 4, Ga is 1 to 3 and Zn is 2 to 4. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn = 5:1:6 or thereabout, this includes a case where, when In is taken as 5, Ga is more than 0.1 and 2 or less and Zn is 5 to 7. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn = 1:1:1 or thereabout, this includes a case where, when In is taken as 1, Ga is more than 0.1 and 2 or less and Zn is more than 0.1 and 2 or less.

[0317] The semiconductor layer may have two or more metal oxide layers with different compositions. For example, a stacked structure of a first metal oxide layer having an atomic ratio of In:M:Zn=1:3:4 or a similar composition and a second metal oxide layer having an atomic ratio of In:M:Zn=1:1:1 or a similar composition provided on the first metal oxide layer is suitable. Gallium or aluminum is particularly preferred as the element M.

[0318] Alternatively, for example, a stacked structure of any one selected from indium oxide, indium gallium oxide, and IGZO and any one selected from IAZO, IAGZO, and ITZO (registered trademark) may be used.

[0319] Examples of crystalline oxide semiconductors include c-axis-aligned crystalline (CAAC)-OS, nanocrystalline (nc)-OS, and the like.

[0320] Alternatively, a transistor using silicon for a channel formation region (Si transistor) may be used. Examples of silicon include single crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, a transistor having low temperature polysilicon (LTPS) in a semiconductor layer (also referred to as an LTPS transistor) may be used. An LTPS transistor has high field-effect mobility and favorable frequency characteristics.

[0321] By using Si transistors such as LTPS transistors, circuits that need to be driven at high frequencies (such as data driver circuits) can be built on the same substrate as the display unit, which simplifies the external circuits mounted on the display device and reduces component and mounting costs.

[0322] An OS transistor has significantly higher field-effect mobility than a transistor using amorphous silicon. Furthermore, an OS transistor has significantly lower source-drain leakage current (also referred to as off-state current) in an off state and can hold charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of an OS transistor can reduce the power consumption of a display device.

[0323] Furthermore, to increase the emission luminance of a light-emitting element included in a pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting element. To achieve this, it is necessary to increase the source-drain voltage of a driving transistor included in the pixel circuit. Since an OS transistor has a higher source-drain withstand voltage than a Si transistor, a high voltage can be applied between the source and drain of the OS transistor. Therefore, by using an OS transistor as the driving transistor included in a pixel circuit, it is possible to increase the amount of current flowing through the light-emitting element and increase the emission luminance of the light-emitting element.

[0324] Furthermore, when the transistor operates in the saturation region, the OS transistor can reduce the change in source-drain current with respect to the change in gate-source voltage compared to a Si transistor. Therefore, by using an OS transistor as a driving transistor included in a pixel circuit, the current flowing between the source and drain can be precisely controlled by controlling the gate-source voltage. Therefore, the amount of current flowing to the light-emitting element can be controlled. This allows for a greater number of gray levels in the pixel circuit.

[0325] Furthermore, in terms of the saturation characteristics of the current that flows when a transistor is driven in the saturation region, an OS transistor can pass a more stable current (saturation current) than a Si transistor, even when the source-drain voltage gradually increases. Therefore, by using an OS transistor as a driving transistor, a stable current can be passed to a light-emitting element, even when, for example, the current-voltage characteristics of an organic EL element vary. In other words, when an OS transistor is driven in the saturation region, the source-drain current of the OS transistor remains almost unchanged even when the source-drain voltage increases. Therefore, the light-emitting luminance of the light-emitting element can be stabilized.

[0326] As described above, by using an OS transistor for a driving transistor included in a pixel circuit, it is possible to suppress black floating, increase light emission luminance, increase gray levels, and suppress variations in light-emitting elements.

[0327] The transistors included in the circuit 164 and the transistors included in the display portion 37b may have the same structure or different structures. The transistors included in the circuit 164 may all have the same structure or may have two or more types. Similarly, the transistors included in the display portion 37b may all have the same structure or may have two or more types.

[0328] All the transistors included in the display portion 37b may be OS transistors, or all the transistors included in the display portion 37b may be Si transistors. Alternatively, some of the transistors included in the display portion 37b may be OS transistors and the rest may be Si transistors.

[0329] For example, by using both an LTPS transistor and an OS transistor in the display portion 37b, a display device with low power consumption and high driving capability can be realized. A configuration in which an LTPS transistor and an OS transistor are combined is sometimes called an LTPO. Note that, for example, it is preferable to use an OS transistor as a transistor that functions as a switch for controlling the conduction / non-conduction of a wiring, and to use an LTPS transistor as a transistor for controlling current.

[0330] For example, one of the transistors included in the display unit 37b functions as a transistor for controlling the current flowing through the light-emitting element and can be called a driving transistor. One of the source and drain of the driving transistor is electrically connected to the pixel electrode of the light-emitting element. It is preferable to use an LTPS transistor as the driving transistor. This allows the current flowing through the light-emitting element to be increased.

[0331] On the other hand, the other transistor included in the display portion 37b functions as a switch for controlling pixel selection / deselection and can also be referred to as a selection transistor. The gate of the selection transistor is electrically connected to a gate line, and one of the source and drain is electrically connected to a data line. An OS transistor is preferably used as the selection transistor. This allows the gradation of pixels to be maintained even when the frame frequency is significantly reduced (for example, 1 fps or less), thereby reducing power consumption by stopping the driver when displaying a still image.

[0332] As described above, the display device of one embodiment of the present invention can have a high aperture ratio, high definition, high display quality, and low power consumption.

[0333] A display device according to one embodiment of the present invention includes an OS transistor and a light-emitting element with an MML structure. This structure can significantly reduce leakage current that can flow through the transistor and between adjacent light-emitting elements. Furthermore, with this structure, when an image is displayed on the display device, a viewer can observe one or more of image clarity, image sharpness, high saturation, and a high contrast ratio. By using a structure in which leakage current that can flow through the transistor and lateral leakage current between light-emitting elements are significantly reduced, light leakage that can occur during black display (so-called floating black) can be minimized.

[0334] In particular, by applying the SBS structure to light-emitting elements having an MML structure, the layers provided between the light-emitting elements are separated, thereby eliminating or extremely reducing side leakage.

[0335] 28B and 28C show other examples of transistor configurations.

[0336] The transistor 209 and the transistor 210 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a first gate insulating layer, a semiconductor layer 231 including a channel formation region 231i and a pair of low-resistance regions 231n, a conductive layer 222a electrically connected to one of the pair of low-resistance regions 231n, a conductive layer 222b electrically connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 functioning as a second gate insulating layer, a conductive layer 223 functioning as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel formation region 231i. The insulating layer 225 is located at least between the conductive layer 223 and the channel formation region 231i. Furthermore, an insulating layer 218 covering the transistor may be provided.

[0337] 28B shows an example in which the insulating layer 225 covers the top surface and side surfaces of the semiconductor layer 231. The conductive layer 222a and the conductive layer 222b are electrically connected to the low-resistance region 231n through openings provided in the insulating layer 225 and the insulating layer 215, respectively. One of the conductive layer 222a and the conductive layer 222b functions as a source, and the other functions as a drain.

[0338] 28C , the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231 but does not overlap with the low-resistance region 231n. For example, the insulating layer 225 is processed using the conductive layer 223 as a mask, thereby manufacturing the structure shown in FIG. 28C . In FIG. 28C , the insulating layer 215 is provided to cover the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and the conductive layer 222b are electrically connected to the low-resistance region 231n through the openings in the insulating layer 215.

[0339] A connection portion 204 is provided in an area of ​​the substrate 17b that does not overlap with the substrate 13b. In the connection portion 204, the wiring 165 is electrically connected to the FPC 177 via a conductive layer 166 and a connection layer 242. The conductive layer 166 can be a conductive layer obtained by processing the same conductive film as the conductive film that becomes the conductive layer 171. The conductive layer 166 is exposed on the top surface of the connection portion 204. This allows the connection portion 204 and the FPC 177 to be electrically connected via the connection layer 242.

[0340] The materials that can be used for the substrate 120 can be used for the substrate 17b and the substrate 13b.

[0341] The adhesive layer 142 can be made of a material that can be used for the adhesive layer 122 .

[0342] The connection layer 242 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0343] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0344] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0345] Embodiment 5 In this embodiment, a light-emitting element that can be used for a display device of one embodiment of the present invention will be described with reference to drawings.

[0346] 29A, the light-emitting element has an EL layer 763 between a pair of electrodes (a lower electrode 761 and an upper electrode 762). The EL layer 763 can be composed of a plurality of layers such as a layer 780, a light-emitting layer 771, and a layer 790.

[0347] The light-emitting layer 771 contains at least a light-emitting substance.

[0348] When the lower electrode 761 is an anode and the upper electrode 762 is a cathode, the layer 780 includes one or more of a layer containing a substance with high hole-injecting properties (hole-injecting layer), a layer containing a substance with high hole-transporting properties (hole-transporting layer), and a layer containing a substance with high electron-blocking properties (electron-blocking layer). The layer 790 also includes one or more of a layer containing a substance with high electron-injecting properties (electron-injecting layer), a layer containing a substance with high electron-transporting properties (electron-transporting layer), and a layer containing a substance with high hole-blocking properties (hole-blocking layer). When the lower electrode 761 is a cathode and the upper electrode 762 is an anode, the layers 780 and 790 have the opposite structures to those described above.

[0349] A structure having the layer 780, the light-emitting layer 771, and the layer 790 provided between a pair of electrodes can function as a single light-emitting unit, and the structure of FIG. 29A is referred to as a single structure in this specification and the like.

[0350] 29B shows a modified example of the EL layer 763 included in the light-emitting element shown in Fig. 29A. Specifically, the light-emitting element shown in Fig. 29B includes a layer 781 over a lower electrode 761, a layer 782 over the layer 781, a light-emitting layer 771 over the layer 782, a layer 791 over the light-emitting layer 771, a layer 792 over the layer 791, and an upper electrode 762 over the layer 792.

[0351] When the lower electrode 761 is an anode and the upper electrode 762 is a cathode, for example, the layer 781 can be a hole injection layer, the layer 782 can be a hole transport layer, the layer 791 can be an electron transport layer, and the layer 792 can be an electron injection layer. When the lower electrode 761 is a cathode and the upper electrode 762 is an anode, the layer 781 can be an electron injection layer, the layer 782 can be an electron transport layer, the layer 791 can be a hole transport layer, and the layer 792 can be a hole injection layer. Such a layer structure allows carriers to be efficiently injected into the light-emitting layer 771, and the efficiency of carrier recombination in the light-emitting layer 771 can be increased.

[0352] 29C and 29D, a variation of the single structure is a configuration in which multiple light-emitting layers (light-emitting layer 771, light-emitting layer 772, and light-emitting layer 773) are provided between layer 780 and layer 790. While an example having three light-emitting layers is shown in FIGS. 29C and 29D, the number of light-emitting layers in a light-emitting element with a single structure may be two, or may be four or more. Furthermore, a light-emitting element with a single structure may have a buffer layer between the two light-emitting layers.

[0353] 29E and 29F, a structure in which a plurality of light-emitting units (light-emitting unit 763a and light-emitting unit 763b) are connected in series via a charge generation layer 785 (also referred to as an intermediate layer) is referred to as a tandem structure in this specification. The tandem structure may also be referred to as a stack structure. The tandem structure can provide a light-emitting element capable of emitting high-luminance light. Furthermore, the tandem structure can reduce the current required to obtain the same luminance compared to a single structure, thereby improving reliability.

[0354] 29D and 29F are examples of display devices having a layer 764 overlapping with a light-emitting element. Fig. 29D is an example in which the layer 764 overlaps with the light-emitting element shown in Fig. 29C, and Fig. 29F is an example in which the layer 764 overlaps with the light-emitting element shown in Fig. 29E. In Fig. 29D and 29F, a conductive film that transmits visible light is used for the upper electrode 762 in order to extract light to the upper electrode 762 side.

[0355] The layer 764 can be a color conversion layer, a color filter (coloring layer), or both.

[0356] 29C and 29D , the light-emitting layers 771, 772, and 773 may be made of light-emitting materials that emit light of the same color, or even the same light-emitting material. For example, the light-emitting layers 771, 772, and 773 may be made of a light-emitting material that emits blue light. In a subpixel that emits blue light, blue light emitted by a light-emitting element can be extracted. In a subpixel that emits red light and a subpixel that emits green light, a color conversion layer is provided as the layer 764 shown in FIG. 29D to convert blue light emitted by the light-emitting element into light with a longer wavelength, thereby extracting red or green light. The layer 764 preferably includes both a color conversion layer and a coloring layer. A portion of the light emitted by the light-emitting element may be transmitted directly without being converted by the color conversion layer. By extracting the light that has passed through the color conversion layer through the coloring layer, light other than the desired color can be absorbed by the coloring layer, thereby improving the color purity of the light emitted by the subpixel.

[0357] 29C and 29D , light-emitting layers 771, 772, and 773 may each contain light-emitting materials with different emission colors. When the light emitted from the light-emitting layers 771, 772, and 773 has a complementary color relationship, white light can be obtained. For example, a light-emitting element with a single structure preferably has a light-emitting layer containing a light-emitting material that emits blue light and a light-emitting layer containing a light-emitting material that emits visible light with a wavelength longer than blue.

[0358] A color filter may be provided as layer 764 shown in Figure 29D. When white light passes through the color filter, light of a desired color can be obtained.

[0359] For example, when a light-emitting element having a single structure has three light-emitting layers, it preferably has a light-emitting layer having a light-emitting material that emits red (R) light, a light-emitting layer having a light-emitting material that emits green (G) light, and a light-emitting layer having a light-emitting material that emits blue (B) light. The stacking order of the light-emitting layers can be R, G, B from the anode side, or R, B, G from the anode side, etc. In this case, a buffer layer may be provided between R and G or B.

[0360] Furthermore, for example, when a light-emitting element with a single structure has two light-emitting layers, a structure having a light-emitting layer containing a light-emitting substance that emits blue (B) light and a light-emitting layer containing a light-emitting substance that emits yellow (Y) light is preferable. Such a structure may be referred to as a BY single structure.

[0361] A light-emitting element that emits white light preferably contains two or more types of light-emitting materials. To obtain white light emission, light-emitting materials may be selected such that the respective emissions of the two or more light-emitting materials have a complementary color relationship. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary to each other, a light-emitting element that emits white light as a whole can be obtained. The same applies to a light-emitting element having three or more light-emitting layers.

[0362] 29C and 29D, the layer 780 and the layer 790 may each be independently formed into a laminated structure consisting of two or more layers, as shown in FIG. 29B.

[0363] 29E and 29F , the light-emitting layers 771 and 772 may be formed using light-emitting materials that emit light of the same color, or even the same light-emitting material. For example, in the light-emitting elements included in the subpixels that emit light of each color, the light-emitting layers 771 and 772 may each be formed using a light-emitting material that emits blue light. In the subpixel that emits blue light, the blue light emitted by the light-emitting element can be extracted. In the subpixels that emit red light and the subpixels that emit green light, a color conversion layer can be provided as the layer 764 shown in FIG. 29F to convert the blue light emitted by the light-emitting element into light with a longer wavelength, thereby allowing red or green light to be extracted. Furthermore, it is preferable to use both a color conversion layer and a coloring layer as the layer 764.

[0364] 29E or 29F are used for the subpixels emitting light of each color, different light-emitting materials may be used for each subpixel. Specifically, in a light-emitting element included in a subpixel emitting red light, light-emitting materials that emit red light may be used for the light-emitting layers 771 and 772. Similarly, in a light-emitting element included in a subpixel emitting green light, light-emitting materials that emit green light may be used for the light-emitting layers 771 and 772. In a light-emitting element included in a subpixel emitting blue light, light-emitting materials that emit blue light may be used for the light-emitting layers 771 and 772. A display device having such a configuration employs light-emitting elements with a tandem structure and can be said to have an SBS structure. Therefore, it can have the advantages of both the tandem structure and the SBS structure. This allows for a highly reliable light-emitting element to be realized.

[0365] 29E and 29F, light-emitting layers 771 and 772 may be made of light-emitting materials with different light emission colors. When the light emitted by light-emitting layer 771 and the light emitted by light-emitting layer 772 are complementary colors, white light can be obtained. A color filter may be provided as layer 764 shown in FIG. 29F. When white light passes through the color filter, light of a desired color can be obtained.

[0366] 29E and 29F show an example in which the light-emitting unit 763a has one light-emitting layer 771 and the light-emitting unit 763b has one light-emitting layer 772, but this is not limiting. Each of the light-emitting unit 763a and the light-emitting unit 763b may have two or more light-emitting layers.

[0367] 29E and 29F illustrate light-emitting elements having two light-emitting units, but the present invention is not limited to this. The light-emitting element may have three or more light-emitting units. Note that a configuration having two light-emitting units may be referred to as a two-tiered tandem structure, and a configuration having three light-emitting units may be referred to as a three-tiered tandem structure.

[0368] 29E and 29F, the light-emitting unit 763a includes a layer 780a, a light-emitting layer 771, and a layer 790a, and the light-emitting unit 763b includes a layer 780b, a light-emitting layer 772, and a layer 790b.

[0369] When the lower electrode 761 is an anode and the upper electrode 762 is a cathode, the layers 780a and 780b each have one or more of a hole injection layer, a hole transport layer, and an electron blocking layer. The layers 790a and 790b each have one or more of an electron injection layer, an electron transport layer, and a hole blocking layer. When the lower electrode 761 is a cathode and the upper electrode 762 is an anode, the layers 780a and 790a have the opposite structures to those described above, and the layers 780b and 790b also have the opposite structures to those described above.

[0370] When the lower electrode 761 is an anode and the upper electrode 762 is a cathode, for example, the layer 780a may have a hole injection layer, a hole transport layer on the hole injection layer, and an electron blocking layer on the hole transport layer. The layer 790a may have an electron transport layer and a hole blocking layer between the light-emitting layer 771 and the electron transport layer. The layer 780b may have a hole transport layer and an electron blocking layer on the hole transport layer. The layer 790b may have an electron transport layer, an electron injection layer on the electron transport layer, and a hole blocking layer between the light-emitting layer 772 and the electron transport layer. When the lower electrode 761 is a cathode and the upper electrode 762 is an anode, for example, the layer 780a may have an electron injection layer, an electron transport layer on the electron injection layer, and an electron blocking layer on the electron transport layer. Layer 790a may have a hole transport layer and may further have an electron blocking layer between light-emitting layer 771 and the hole transport layer. Layer 780b may have an electron transport layer and may further have a hole blocking layer on the electron transport layer. Layer 790b may have a hole transport layer and a hole injection layer on the hole transport layer and may further have an electron blocking layer between light-emitting layer 772 and the hole transport layer.

[0371] When a light-emitting element having a tandem structure is fabricated, two light-emitting units are stacked via a charge generation layer 785. The charge generation layer 785 has at least a charge generation region. The charge generation layer 785 has a function of injecting electrons into one of the two light-emitting units and injecting holes into the other when a voltage is applied between a pair of electrodes.

[0372] An example of a light emitting device having a tandem structure is shown in FIGS. 30A to 30C.

[0373] 30A shows a configuration having three light-emitting units. In FIG. 30A , a plurality of light-emitting units (light-emitting unit 763a, light-emitting unit 763b, and light-emitting unit 763c) are connected in series via charge generation layers 785. Furthermore, light-emitting unit 763a includes layer 780a, light-emitting layer 771, and layer 790a. Light-emitting unit 763b includes layer 780b, light-emitting layer 772, and layer 790b. Light-emitting unit 763c includes layer 780c, light-emitting layer 773, and layer 790c. Note that layer 780c can have a structure applicable to layers 780a and 780b, and layer 790c can have a structure applicable to layers 790a and 790b.

[0374] 30A , the light-emitting layers 771, 772, and 773 preferably contain light-emitting materials that emit light of the same color. Specifically, the light-emitting layers 771, 772, and 773 may each contain a red (R) light-emitting material (a so-called R\R\R three-stage tandem structure), the light-emitting layers 771, 772, and 773 may each contain a green (G) light-emitting material (a so-called G\G\G three-stage tandem structure), or the light-emitting layers 771, 772, and 773 may each contain a blue (B) light-emitting material (a so-called B\B\B three-stage tandem structure). Note that "a\b" means that a light-emitting unit containing a light-emitting material that emits light of b is provided on a light-emitting unit containing a light-emitting material that emits light of a, via a charge-generating layer, and a and b represent colors.

[0375] 30A , light-emitting materials with different light-emitting colors may be used for some or all of the light-emitting layers 771, 772, and 773. Examples of combinations of the light-emitting colors of the light-emitting layers 771, 772, and 773 include a configuration in which two of them are blue (B) and the remaining one is yellow (Y), and a configuration in which one of them is red (R), the other one is green (G), and the remaining one is blue (B).

[0376] The configuration of the light-emitting unit is not limited to that shown in FIG. 30A . For example, as shown in FIG. 30B , a tandem light-emitting element in which light-emitting units having a plurality of light-emitting layers are stacked may be used. FIG. 30B shows a configuration in which two light-emitting units (light-emitting unit 763a and light-emitting unit 763b) are connected in series via a charge generation layer 785. Furthermore, the light-emitting unit 763a includes a layer 780a, a light-emitting layer 771a, a light-emitting layer 771b, a light-emitting layer 771c, and a layer 790a. The light-emitting unit 763b includes a layer 780b, a light-emitting layer 772a, a light-emitting layer 772b, a light-emitting layer 772c, and a layer 790b.

[0377] In FIG. 30B , light-emitting materials having complementary colors are selected for the light-emitting layers 771a, 771b, and 771c, and the light-emitting unit 763a is configured to emit white light (W). Light-emitting materials having complementary colors are also selected for the light-emitting layers 772a, 772b, and 772c, and the light-emitting unit 763b is configured to emit white light (W). That is, the structure shown in FIG. 30B is a two-tiered W\W tandem structure. There are no particular limitations on the stacking order of the light-emitting materials having complementary colors. The implementer can select the optimal stacking order as appropriate. Although not shown, a three-tiered W\W\W tandem structure or a four-tiered or more tandem structure may also be used.

[0378] In addition, when a light-emitting element having a tandem structure is used, there are a B\Y or Y\B two-stage tandem structure having a light-emitting unit that emits yellow (Y) light and a light-emitting unit that emits blue (B) light, a R.G\B or B\R.G two-stage tandem structure having a light-emitting unit that emits red (R) and green (G) light and a light-emitting unit that emits blue (B) light, a light-emitting unit that emits yellow (Y) light and a light-emitting unit that emits blue (B) light, and a light-emitting unit that emits blue (B) light. Examples of such a tandem structure include a B\Y\B three-stage tandem structure having a light-emitting unit that emits blue (B) light, a light-emitting unit that emits yellow-green (YG) light, and a light-emitting unit that emits blue (B) light, in that order, a B\YG\B three-stage tandem structure having a light-emitting unit that emits blue (B) light, a light-emitting unit that emits green (G) light, and a light-emitting unit that emits blue (B) light, in that order, and a B\G\B three-stage tandem structure having a light-emitting unit that emits blue (B) light, a light-emitting unit that emits green (G) light, and a light-emitting unit that emits blue (B) light, in that order. Note that "a·b" means that one light-emitting unit has a light-emitting substance that emits light of a and a light-emitting substance that emits light of b.

[0379] Furthermore, as shown in FIG. 30C, a light-emitting unit having one light-emitting layer and a light-emitting unit having multiple light-emitting layers may be combined.

[0380] 30C , a plurality of light-emitting units (light-emitting unit 763a, light-emitting unit 763b, and light-emitting unit 763c) are connected in series via charge generation layers 785. Light-emitting unit 763a includes layer 780a, light-emitting layer 771, and layer 790a. Light-emitting unit 763b includes layer 780b, light-emitting layer 772a, light-emitting layer 772b, light-emitting layer 772c, and layer 790b. Light-emitting unit 763c includes layer 780c, light-emitting layer 773, and layer 790c.

[0381] For example, in the configuration shown in Figure 30C, a three-stage tandem structure of B\R.G.YG\B can be applied, in which light-emitting unit 763a is a light-emitting unit that emits blue (B) light, light-emitting unit 763b is a light-emitting unit that emits red (R), green (G), and yellow-green (YG) light, and light-emitting unit 763c is a light-emitting unit that emits blue (B) light.

[0382] For example, the number of layers of the light-emitting units and the order of the colors can be, from the anode side, a two-layer structure of B and Y, a two-layer structure of B and light-emitting unit X, a three-layer structure of B, Y, and B, and a three-layer structure of B, X, and B. The number of layers of the light-emitting layers in light-emitting unit X and the order of the colors can be, from the anode side, a two-layer structure of R and Y, a two-layer structure of R and G, a two-layer structure of G and R, a three-layer structure of G, R, and G, or a three-layer structure of R, G, and R. Furthermore, another layer can be provided between the two light-emitting layers.

[0383] Next, materials that can be used for the light-emitting element will be described.

[0384] Of the lower electrode 761 and the upper electrode 762, a conductive film that transmits visible light is used for the electrode from which light is extracted. A conductive film that reflects visible light is preferably used for the electrode from which light is not extracted. When the display device has a light-emitting element that emits infrared light, a conductive film that transmits visible light and infrared light is preferably used for the electrode from which light is extracted, and a conductive film that reflects visible light and infrared light is preferably used for the electrode from which light is not extracted.

[0385] A conductive film that transmits visible light may also be used for the electrode on the side from which light is not extracted. In this case, the electrode is preferably disposed between the reflective layer and the EL layer 763. That is, light emitted from the EL layer 763 may be reflected by the reflective layer and extracted from the display device.

[0386] Materials for forming the pair of electrodes of the light-emitting element can include metals, alloys, electrically conductive compounds, and mixtures thereof. Specific examples of such materials include metals such as aluminum, magnesium, titanium, chromium, manganese, iron, cobalt, nickel, copper, gallium, zinc, indium, tin, molybdenum, tantalum, tungsten, palladium, gold, platinum, silver, yttrium, and neodymium, as well as alloys containing appropriate combinations of these metals. Examples of such materials include indium tin oxide, silicon-containing indium tin oxide, indium zinc oxide, and tungsten-containing indium zinc oxide. Examples of such materials include aluminum-containing alloys such as an alloy of aluminum, nickel, and lanthanum (Al-Ni-La), and silver-containing alloys such as an alloy of silver and magnesium and an alloy of silver, palladium, and copper (APC). Other examples of the material include elements belonging to Group 1 or 2 of the periodic table (e.g., lithium, cesium, calcium, or strontium) that are not listed above as examples, rare earth metals such as europium and ytterbium, alloys containing appropriate combinations of these, and graphene.

[0387] It is preferable that a microcavity structure is applied to the light-emitting element. Therefore, one of a pair of electrodes of the light-emitting element is preferably an electrode that is transmissive and reflective to visible light (semi-transmissive / semi-reflective electrode), and the other is preferably an electrode that is reflective to visible light (reflective electrode). When the light-emitting element has a microcavity structure, light emitted from the light-emitting layer can be resonated between the two electrodes, thereby intensifying the light emitted from the light-emitting element.

[0388] The semi-transmitting / semi-reflective electrode can have a stacked structure of a conductive layer that can be used as a reflective electrode and a conductive layer that can be used as an electrode that is transparent to visible light (also called a transparent electrode), for example.

[0389] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode having a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more for the transparent electrode of the light-emitting element. The visible light reflectance of the semi-transmissive / semi-reflective electrode is 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. Furthermore, the resistivity of these electrodes is 1×10 −２ Preferably, it is Ωcm or less.

[0390] A light-emitting element has at least a light-emitting layer. The light-emitting element may further include, as a layer other than the light-emitting layer, a layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a hole-blocking material, a substance with high electron-transport properties, an electron-blocking material, a substance with high electron-injection properties, or a bipolar substance (a substance with high electron-transport properties and high hole-transport properties). For example, the light-emitting element may have, in addition to the light-emitting layer, one or more layers selected from a hole-injection layer, a hole-transport layer, a hole-blocking layer, a charge-generating layer, an electron-blocking layer, an electron-transport layer, and an electron-injection layer.

[0391] The light-emitting element can be made of either a low-molecular-weight compound or a high-molecular-weight compound, and may contain an inorganic compound. Each of the layers constituting the light-emitting element can be formed by a method such as a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, or a coating method.

[0392] The light-emitting layer contains one or more light-emitting materials. As the light-emitting material, a material that emits light of blue, purple, blue-purple, green, yellow-green, yellow, orange, red, or the like is appropriately used. Furthermore, a material that emits near-infrared light can also be used as the light-emitting material.

[0393] Examples of the light-emitting material include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0394] 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.

[0395] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, a pyrazine skeleton, or a pyridine skeleton; organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand; platinum complexes; and rare earth metal complexes.

[0396] The light-emitting layer may contain one or more organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). As the one or more organic compounds, one or both of a substance with high hole-transporting properties (hole-transporting material) and a substance with high electron-transporting properties (electron-transporting material) can be used. As the hole-transporting material, a substance with high hole-transporting properties that can be used in a hole-transporting layer, which will be described later, can be used. As the electron-transporting material, a substance with high electron-transporting properties that can be used in an electron-transporting layer, which will be described later, can be used. Furthermore, as the one or more organic compounds, a bipolar material or a TADF material may be used.

[0397] The light-emitting layer preferably includes, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material, which are a combination that easily forms an exciplex. This configuration allows efficient emission using Exciplex-Triple Energy Transfer (ExTET), which is energy transfer from the exciplex to the light-emitting material (phosphorescent material). By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material, the energy transfer becomes smooth and efficient emission can be achieved. This configuration allows the light-emitting element to simultaneously achieve high efficiency, low-voltage operation, and a long lifetime.

[0398] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a substance with high hole injection properties, such as an aromatic amine compound and a composite material containing a hole transport material and an acceptor material (electron acceptor material).

[0399] As the hole transporting material, a substance having high hole transporting properties that can be used for the hole transport layer, which will be described later, can be used.

[0400] As the acceptor material, for example, an oxide of a metal belonging to Groups 4 to 8 of the periodic table can be used. Specific examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is particularly preferred because it is stable in the air, has low hygroscopicity, and is easy to handle. Alternatively, an organic acceptor material containing fluorine can be used. Alternatively, an organic acceptor material such as a quinodimethane derivative, a chloranil derivative, or a hexaazatriphenylene derivative can be used.

[0401] For example, as a substance with high hole-injection properties, a material containing a hole-transporting material and an oxide of a metal belonging to Groups 4 to 8 in the periodic table (typically, molybdenum oxide) may be used.

[0402] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light emitting layer. The hole transport layer is a layer that contains a hole transporting material. The hole transporting material is a material having a concentration of 1×10 −６ cm ２ A substance having a hole mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, a substance having a high hole transporting property, such as a π-electron-rich heteroaromatic compound (e.g., a carbazole derivative, a thiophene derivative, or a furan derivative) or an aromatic amine (a compound having an aromatic amine skeleton), is preferred.

[0403] The electron blocking layer is provided in contact with the light-emitting layer. The electron blocking layer is a layer containing a material that has hole transport properties and can block electrons. The electron blocking layer can be made of a material that has electron blocking properties among the hole transport materials described above.

[0404] The electron blocking layer has hole transport properties and can therefore also be called a hole transport layer. Furthermore, a layer of the hole transport layer that has electron blocking properties can also be called an electron blocking layer.

[0405] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light emitting layer. The electron transport layer is a layer that contains an electron transporting material. The electron transporting material is a material having a concentration of 1×10 −６ cm ２ / Vs or more is preferred. Note that other substances can also be used as long as they have a higher electron transporting property than holes. As the electron-transporting material, a metal complex having a quinoline skeleton, a metal complex having a benzoquinoline skeleton, a metal complex having an oxazole skeleton, or a metal complex having a thiazole skeleton can be used, 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, or other π-electron-deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds.

[0406] The hole-blocking layer is provided in contact with the light-emitting layer. The hole-blocking layer is a layer containing a material that has electron transport properties and can block holes. The hole-blocking layer can be made of a material that has hole-blocking properties and is selected from the above electron-transporting materials.

[0407] The hole blocking layer has electron transport properties and can therefore also be called an electron transport layer. Furthermore, a layer of the electron transport layer that has hole blocking properties can also be called a hole blocking layer.

[0408] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a substance with high electron injection properties. Examples of the substance with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the substance with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0409] Furthermore, it is preferable that the LUMO level of the material with high electron injection properties has a small difference from the work function value of the material used for the cathode (specifically, 0.5 eV or less).

[0410] The electron injection layer may contain, for example, lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ｘ , where X is an arbitrary number), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatolithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviation: LiPPP), lithium oxide (LiO ｘ ), alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. The electron injection layer may have a stacked structure of two or more layers. For example, the stacked structure may include a structure in which lithium fluoride is used in the first layer and ytterbium is provided in the second layer.

[0411] The electron injection layer may include an electron transporting material. For example, a compound having an unshared electron pair 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 (a pyrimidine ring, a pyrazine ring, and a pyridazine ring), and a triazine ring can be used.

[0412] The lowest unoccupied molecular orbital (LUMO) level of an organic compound having an unshared electron pair is preferably −3.6 eV or more and −2.3 eV or less. Generally, the highest occupied molecular orbital (HOMO) level and the LUMO level of an organic compound can be estimated by CV (cyclic voltammetry), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, or the like.

[0413] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviation: BPhen), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2,2′-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), diquinoxalino[2,3-a:2′,3′-c]phenazine (abbreviation: HATNA), or 2,4,6-tris[3′-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz) can be used as the organic compound having an unshared electron pair. Note that NBPhen has a higher glass transition point (Tg) and is more heat resistant than BPhen.

[0414] As described above, the charge generation layer has at least a charge generation region. The charge generation region preferably contains an acceptor material, for example, a hole transport material and an acceptor material applicable to the hole injection layer.

[0415] The charge generation layer preferably includes a layer containing a substance with high electron injection properties. This layer can also be called an electron injection buffer layer. The electron injection buffer layer is preferably provided between the charge generation region and the electron transport layer. By providing the electron injection buffer layer, the injection barrier between the charge generation region and the electron transport layer can be alleviated, so that electrons generated in the charge generation region can be easily injected into the electron transport layer.

[0416] The electron injection buffer layer preferably contains an alkali metal or an alkaline earth metal, and may contain, for example, an alkali metal compound or an alkaline earth metal compound. Specifically, the electron injection buffer layer preferably contains an inorganic compound containing an alkali metal and oxygen, or an inorganic compound containing an alkaline earth metal and oxygen, and may contain an inorganic compound containing lithium and oxygen (for example, lithium oxide (Li ２ In addition, the electron injection buffer layer can be suitably made of the materials applicable to the electron injection layer described above.

[0417] The charge generation layer preferably has a layer containing a substance with high electron transport properties. This layer can also be called an electron relay layer. The electron relay layer is preferably provided between the charge generation region and the electron injection buffer layer. When the charge generation layer does not have an electron injection buffer layer, the electron relay layer is preferably provided between the charge generation region and the electron transport layer. The electron relay layer has the function of preventing interaction between the charge generation region and the electron injection buffer layer (or the electron transport layer) and smoothly transferring electrons.

[0418] As the electron relay layer, it is preferable to use a phthalocyanine-based material such as copper (II) phthalocyanine (abbreviated as CuPc) or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0419] It should be noted that the charge generation region, the electron injection buffer layer, and the electron relay layer may not be clearly distinguishable from each other, for example, based on their cross-sectional shapes or characteristics.

[0420] The charge generation layer may have a donor material instead of an acceptor material. For example, the charge generation layer may have a layer containing an electron transport material and a donor material that can be used for the electron injection layer.

[0421] When light-emitting units are stacked, an increase in driving voltage can be suppressed by providing a charge generating layer between two light-emitting units.

[0422] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0423] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0424] 10: Electronic device, 11a: Display device, 11aL: Display device, 11aR: Display device, 11b: Display device, 11bL: Display device, 11bR: Display device, 12L: Lens, 12R: Lens, 12: Lens, 13a: Substrate, 13b: Substrate, 14: Half mirror, 15: Housing, 16: Substrate, 17a: Substrate, 17b: Substrate, 18: Substrate, 20: Eye, 27a: Pixel, 27b: Pixel, 34a: Light, 34aA: Light, 34aC: Light, 34b: Light, 34bB: Light, 34bG: Light, 34bR: Light, 34c: Light, 37a: Display unit, 37b: Display unit, 37c: Display unit, 37: Display unit, 8: region, 40: layer, 41a: display device, 41b: display device, 41L: display device, 41R: display device, 41: display device, 42a: gate driver circuit, 42b: gate driver circuit, 42: mounting fixture, 43a: source driver circuit, 43b: source driver circuit, 44: light, 49L: camera, 49R: camera, 50: layer, 51: pixel circuit, 60: layer, 61A: light-emitting element, 61C: light-emitting element, 61: light-emitting element, 63B: light-emitting element, 63G: light-emitting element, 63R: light-emitting element, 100A: display device, 100a: display device, 100b: display device, 100C: display device, 100D: display device, 100E: display device, 100F: display device, 100G: display device, 100H: display device, 101: layer, 107: display unit, 110B: sub-pixel, light-emitting element, 110G: sub-pixel, light-emitting element, 110R: sub-pixel, light-emitting element, 110: pixel, 111B: pixel electrode, 111C: connection electrode, 111G: pixel electrode, 111R: pixel electrode, 111: pixel electrode, 112B: organic layer, 112G: organic layer, 112R: organic layer, 112: organic layer, 113: common electrode, 114: common layer, 120: substrate, 121: protective layer, 122: adhesive layer, 125: insulating layer, 126: Resin layer, 128: layer, 140: connection portion, 142: adhesive layer, 164: circuit, 165: wiring, 166: conductive layer, 168: conductive layer, 171: conductive layer, 172A: EL layer, 172B: EL layer, 172C: EL layer, 172G: EL layer, 172R: EL layer, 173: conductive layer, 174: common layer, 176: IC, 177: FPC, 201: transistor, 204: connection portion, 205: transistor, 209: transistor, 210: transistor, 211: insulating layer, 213: insulating layer, 214: insulating layer, 215: insulating layer, 218: insulating layer, 221: conductive layer, 222a: conductive layer,222b: conductive layer, 223: conductive layer, 225: insulating layer, 231i: channel formation region, 231n: low resistance region, 231: semiconductor layer, 240: capacitor, 241: conductive layer, 242: connection layer, 243: insulating layer, 245: conductive layer, 251: conductive layer, 252: conductive layer, 254: insulating layer, 255a: insulating layer, 255b: insulating layer, 255c: insulating layer, 256: plug, 261: insulating layer, 262: insulating layer, 263: insulating layer, 264: insulating layer, 265: insulating layer, 270A: layer, 270C: layer, 271: protective layer, 272: insulating layer, 273: protective layer, 274a: conductive layer, 274b: conductive layer, 274: plug, 275: plug, 278: insulating layer, 280: display module, 290: FPC, 301A: substrate, 301B: substrate, 301: substrate, 310A: transistor, 310B: transistor, 310: transistor, 311: conductive layer, 312: low resistance region, 313: insulating layer, 314: insulating layer, 315: element isolation layer, 320A: transistor, 320B: transistor, 320: transistor, 321: semiconductor layer, 323: insulating layer, 324: conductive layer, 325: conductive layer, 326: insulating layer, 327: conductive layer, 328: insulating layer, 329: insulating layer, 331: substrate, 332: insulating layer, 335: insulating layer, 336: insulating layer, 341: conductive layer, 342: conductive layer, 343: plug, 344: insulating layer, 345: insulating layer, 346: insulating layer, 347: bump, 348: adhesive layer, 611: substrate, 611a: substrate, 611b: substrate, 612: layer, 612a: layer, 612b: layer, 613: substrate, 613a: substrate, 613b: substrate, 614: adhesive layer, 761: lower electrode , 762: upper electrode, 763a: light-emitting unit, 763b: light-emitting unit, 763c: light-emitting unit, 763: EL layer, 764: layer, 771a: light-emitting layer, 771b: light-emitting layer, 771c: light-emitting layer, 771: light-emitting layer, 772a: light-emitting layer, 772b: light-emitting layer, 772c: light-emitting layer, 772: light-emitting layer, 773: light-emitting layer, 780a: layer, 780b: layer, 780c: layer, 780: layer, 781: layer, 782: layer, 785: charge generation layer, 790a: layer, 790b: layer, 790c: layer, 790: layer, 791: layer, 792: layer,

Claims

1. a first display device, a second display device, a first half mirror, and an eyepiece; the first display device has a first display unit, the second display device has a second display unit and a third display unit, the third display unit is provided so as to surround at least a part of the second display unit in a plan view, the first display unit has a plurality of first pixels, each of the plurality of first pixels has a light-emitting element that exhibits a first color; the second display unit has a plurality of second pixels, each of the plurality of second pixels has a light-emitting element that exhibits a second color and a light-emitting element that exhibits a third color; the third display unit has a plurality of third pixels, each of the plurality of third pixels includes a light-emitting element that exhibits the first color, a light-emitting element that exhibits the second color, and a light-emitting element that exhibits the third color; the first color is one of green and blue, the second color is red, and the third color is the other of green and blue; a pixel density of the third pixel in the third display unit is lower than a pixel density of the first pixel in the first display unit and a pixel density of the second pixel in the second display unit; the first display unit has a function of displaying a first image, the second display unit has a function of displaying a second image, the third display unit has a function of displaying a third image, the first display device is provided at a position where the first image is reflected by the first half mirror and incident on the eyepiece; the second display device is provided at a position where the second image and the third image are transmitted through the first half mirror and incident on the eyepiece; the first image is presented through the eyepiece; the second image is presented through the eyepiece overlaid on the first image; the third image is presented through the eyepiece; An electronic device in which the third image presented through the eyepiece is presented in an area surrounding the first image presented through the eyepiece and the second image presented through the eyepiece.

2. a first display device, a second display device, a first half mirror, and an eyepiece; the first display device has a first display unit, the second display device has a second display unit and a third display unit, the third display unit is provided so as to surround at least a part of the second display unit in a plan view, the first display unit has a plurality of first pixels, each of the plurality of first pixels has a light-emitting element that exhibits a first color; the second display unit has a plurality of second pixels, each of the plurality of second pixels has a light-emitting element that exhibits a second color and a light-emitting element that exhibits a third color; the third display unit has a plurality of third pixels, each of the plurality of third pixels includes a light-emitting element that exhibits the first color, a light-emitting element that exhibits the second color, and a light-emitting element that exhibits the third color; the first color is one of green and blue, the second color is red, and the third color is the other of green and blue; a pixel density of the third pixel in the third display unit is lower than a pixel density of the first pixel in the first display unit and a pixel density of the second pixel in the second display unit; the first display unit has a function of displaying a first image, the second display unit has a function of displaying a second image, the third display unit has a function of displaying a third image, the first display device is provided at a position where the first image passes through the first half mirror and enters the eyepiece; the second display device is provided at a position where the second image and the third image are reflected by the first half mirror and incident on the eyepiece; the first image is presented through the eyepiece; the second image is presented through the eyepiece overlaid on the first image; the third image is presented through the eyepiece; An electronic device in which the third image presented through the eyepiece is presented in an area surrounding the first image presented through the eyepiece and the second image presented through the eyepiece.

3. In claim 1 or claim 2, the pixel density of the first pixel in the first display unit is equal to or greater than 1000 ppi and equal to or less than 20000 ppi, The pixel density of the third pixels in the third display unit is equal to or greater than 50 ppi and less than 1000 ppi.