Display devices, display modules, and electronic devices

Abstract

Provided is a high-definition display device. The present invention comprises a first and second light emitting device, a first and second colored layer, and a first, second, and third insulator, wherein: the first colored layer is disposed so as to overlap the first light emitting device; the second colored layer is disposed so as to overlap the second light emitting device; the first light emitting device and the second light emitting device have the function of emitting white light; the first colored layer has the function of transmitting visible light of a color differing from that of the second colored layer; the first light emitting device has a first conducting layer and a first light-emitting layer on the first conducting layer; the second light emitting device has a second conducting layer and a second light-emitting layer on the second conducting layer; the first insulator is in contact with at least part of a side surface of the first light emitting device; the second insulator is in contact with at least part of a side surface of the second light emitting device; the first insulator and the second insulator are disposed on the third insulator; and the third insulator is disposed so as to cover an end of the first conducting layer and an end of the second conducting layer.

Description

[Technical Field]

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

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

[0003] In recent years, information terminal devices such as smartphones and other mobile phones, tablet devices, and notebook PCs (personal computers) have become widespread. These devices require high-resolution display panels.

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

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

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-324673 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] One aspect of the present invention aims to provide a high-definition display device. One aspect of the present invention aims to provide a high-resolution display device. One aspect of the present invention aims to provide a display device with a high aperture ratio. One aspect of the present invention aims to provide a highly reliable display device. One aspect of the present invention aims to provide a method for manufacturing the above display device.

[0008] Note that the description of these problems does not preclude the existence of other problems. One aspect of the present invention is not necessarily required to solve all of these problems. It is possible to extract other problems from the description of the specification, drawings, and claims. [Means for Solving the Problems]

[0009] One aspect of the present invention has a first light-emitting device, a second light-emitting device, a first colored layer, a second colored layer, a first insulator, a second insulator, and a third insulator. The first colored layer is disposed so as to overlap the first light-emitting device, the second colored layer is disposed so as to overlap the second light-emitting device, the first light-emitting device and the second light-emitting device have a function of emitting white light, the first colored layer has a function of transmitting visible light of a color different from that of the second colored layer, the first light-emitting device has a first conductive layer and a first light-emitting layer on the first conductive layer, the second light-emitting device has a second conductive layer and a second light-emitting layer on the second conductive layer, the first insulator is in contact with at least a part of the side surface of the first light-emitting device, the second insulator is in contact with at least a part of the side surface of the second light-emitting device, the first insulator and the second insulator are disposed on the third insulator, and the third insulator is disposed so as to cover the ends of the first conductive layer and the second conductive layer. It is a display device.

[0010] In the above, the first light-emitting layer may have the same material as the second light-emitting layer.

[0011] In the above, the first light-emitting device has a first light-emitting unit including the first light-emitting layer, a first charge generation layer on the first light-emitting unit, and a second light-emitting unit on the first charge generation layer. The second light-emitting unit has a third light-emitting layer. The second light-emitting device has a third light-emitting unit including the second light-emitting layer, a second charge generation layer on the third light-emitting unit, and a fourth light-emitting unit on the second charge generation layer. The fourth light-emitting unit has a fourth light-emitting layer. This is preferable. Also, in the above, the first light-emitting unit may have the same material as the third light-emitting unit, the first charge generation layer may have the same material as the second charge generation layer, and the second light-emitting unit may have the same material as the fourth light-emitting unit.

[0012] In the above, the first light-emitting unit has a first hole injection layer, a first hole transport layer, and a first electron transport layer; the second light-emitting unit has a second hole transport layer and a second electron transport layer; the third light-emitting unit has a second hole injection layer, a third hole transport layer, and a third electron transport layer; the fourth light-emitting unit has a fourth hole transport layer and a fourth electron transport layer; and the first insulator has sides of the first hole injection layer and the first hole transport layer Preferably, the second insulator is in contact with the sides of the layers, the sides of the first light-emitting layer, the sides of the first electron transport layer, the sides of the first charge generation layer, the sides of the second hole transport layer, the sides of the third light-emitting layer, and the sides of the second electron transport layer, and the second insulator is in contact with the sides of the second hole injection layer, the sides of the third hole transport layer, the sides of the second light-emitting layer, the sides of the third electron transport layer, the sides of the second charge generation layer, the sides of the fourth hole transport layer, the sides of the second light-emitting layer, and the sides of the fourth electron transport layer.

[0013] In the above, it is preferable that the first insulator and the second insulator each have a first layer and a second layer on the first layer, and in the first insulator, the side surface of the first layer is in contact with at least a portion of the side surface of the first light-emitting device, the bottom surface of the first layer is in contact with at least a portion of the third insulator, and the side surface and bottom surface of the second layer are in contact with at least a portion of the first layer, and in the second insulator, the side surface of the first layer is in contact with at least a portion of the side surface of the second light-emitting device, the bottom surface of the first layer is in contact with at least a portion of the third insulator, and the side surface and bottom surface of the second layer are in contact with at least a portion of the first layer. Furthermore, it is preferable that the first layer contains aluminum oxide and the second layer contains silicon nitride.

[0014] In the above, it is preferable that the side surface of the first light-emitting layer and the side surface of the second light-emitting layer face each other, and that the distance between the side surface of the first light-emitting layer and the side surface of the second light-emitting layer is 8 μm or less.

[0015] One aspect of the present invention is a display module having a display device with any of the above configurations, to which a connector such as a Flexible Printed Circuit (FPC) or TCP (Tape Carrier Package) is attached, or a display module on which an integrated circuit (IC) is mounted by a COG (Chip On Glass) method or a COF (Chip On Film) method, etc.

[0016] One aspect of the present invention is an electronic device having the above-mentioned display module and at least one of a housing, a battery, a camera, a speaker, and a microphone. [Effects of the Invention]

[0017] According to one aspect of the present invention, a high-definition display device can be provided. According to one aspect of the present invention, a high-resolution display device can be provided. According to one aspect of the present invention, a display device with a high aperture ratio can be provided. According to one aspect of the present invention, a highly reliable display device can be provided. According to one aspect of the present invention, a method for manufacturing the above-mentioned display device can be provided.

[0018] Furthermore, the description of these effects does not preclude the existence of other effects. One aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description, drawings, and claims. [Brief explanation of the drawing]

[0019] Figure 1A is a top view showing an example of a display device. Figure 1B is a cross-sectional view showing an example of a display device. Figures 2A and 2B are cross-sectional views showing an example of a display device. Figures 3A and 3B are cross-sectional views showing an example of a display device. Figures 4A to 4E are top views showing examples of pixels in a display device. Figure 5A is a top view showing an example of a display device. Figure 5B is a cross-sectional view showing an example of a display device. Figures 6A to 6G are top views showing examples of pixels in a display device. Figures 7A and 7B are cross-sectional views showing an example of a display device. Figures 8A and 8B are cross-sectional views showing an example of a display device. Figures 9A and 9B are cross-sectional views showing an example of a display device. Figures 10A to 10D show an example of a method for manufacturing a display device. Figures 11A to 11C show an example of a method for manufacturing a display device. Figures 12A to 12C show an example of a method for manufacturing a display device. Figures 13A and 13B show an example of a method for manufacturing a display device. Figure 14 is a perspective view showing an example of a display device. Figure 15A is a cross-sectional view showing an example of a display device. Figures 15B and 15C are cross-sectional views showing an example of a transistor. Figure 16 is a cross-sectional view showing an example of a display device. Figures 17A and 17B show examples of the display module configuration. Figure 18 shows an example of a display device configuration. Figure 19 shows an example of a display device configuration. Figure 20 shows an example of a display device configuration. Figures 21A and 21B show examples of electronic devices. Figures 22A to 22D show examples of electronic devices. Figures 23A to 23F show examples of electronic devices. [Modes for carrying out the invention]

[0020] Embodiments will be described in detail with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be construed as being limited to the descriptions of the embodiments shown below.

[0021] In the invention described below, the same reference numerals are used in common across different drawings for parts that are identical or have similar functions, and repeated explanations are omitted. Furthermore, when referring to similar functions, the hatch patterns are the same, and reference numerals may not be assigned.

[0022] Furthermore, the position, size, and scope of each component shown in the drawings may not represent the actual position, size, and scope for the sake of ease of understanding. Therefore, the disclosed invention is not necessarily limited to the position, size, and scope disclosed in the drawings.

[0023] It should be noted that the terms "film" and "layer" can be interchanged depending on the context or situation. For example, the term "conductive layer" can be changed to "conductive film." Or, for example, the term "insulating film" can be changed to "insulating layer."

[0024] (Embodiment 1) In this embodiment, a display device according to one aspect of the present invention and a method for manufacturing the same will be explained with reference to Figures 1 to 13.

[0025] A display device according to one aspect of the present invention has a display unit in which pixels are arranged in a matrix, and an image can be displayed on the display unit. Each pixel has a light-emitting device that emits white light and a colored layer superimposed on the light-emitting device. Full-color display can be achieved by using a colored layer that transmits visible light of a different color in each pixel. Furthermore, since the light-emitting devices used in each pixel can be formed using the same material, the manufacturing process can be simplified and manufacturing costs can be reduced.

[0026] As the light-emitting device, it is preferable to use EL devices such as OLEDs (Organic Light Emitting Diodes) and QLEDs (Quantum-dot Light Emitting Diodes). Examples of light-emitting materials for EL devices include fluorescent materials, phosphorescent materials, inorganic compounds (such as quantum dot materials), and thermally activated delayed fluorescence (Thermally Activated Delayed Fluorescence (TADF) materials). In addition, LEDs such as microLEDs (Light Emitting Diodes) can also be used as light-emitting devices.

[0027] When the light-emitting device for each pixel is formed from a white-emitting organic EL device, it is not necessary to coat the light-emitting layer separately for each pixel. Therefore, layers other than the pixel electrodes included in the light-emitting device (e.g., the light-emitting layer) can be common to each pixel. However, some layers included in the light-emitting device are relatively conductive, and if a highly conductive layer is provided in common to each pixel, leakage current may occur between pixels. In particular, as the display device becomes higher resolution or has a higher aperture ratio, and the distance between pixels becomes smaller, this leakage current becomes a significant issue that can cause a decrease in the display quality of the display device. Therefore, in a display device according to one aspect of the present invention, the resolution of the display device is increased by forming at least a part of the light-emitting device in an island shape in each pixel. Here, the island-shaped portion of the light-emitting device includes a light-emitting layer.

[0028] For example, island-shaped light-emitting layers can be formed using a vacuum deposition method with a metal mask (also called a shadow mask). However, with this method, deviations from the design occur in the shape and position of the island-shaped light-emitting layers due to various factors such as the precision of the metal mask, the misalignment between the metal mask and the substrate, the deflection of the metal mask, and the spreading of the contour of the formed film due to vapor scattering. This makes it difficult to achieve high resolution and high aperture ratio in display devices.

[0029] In a method for manufacturing a display device according to one aspect of the present invention, island-shaped pixel electrodes (also called lower electrodes) are formed, a layer including an emissive layer (which can be called an EL layer or a part of an EL layer) is formed on one surface, and then a sacrificial layer is formed on the EL layer. Then, a resist mask is formed on the sacrificial layer, and the EL layer and the sacrificial layer are processed using the resist mask to form island-shaped EL layers. In this specification, the sacrificial layer may also be referred to as a mask layer.

[0030] Thus, in the method for manufacturing a display device according to one aspect of the present invention, the island-shaped EL layer is not formed by the pattern of the metal mask, but rather by processing after the EL layer has been deposited on one surface. Therefore, it is possible to realize a high-definition display device or a display device with a high aperture ratio, which has been difficult to achieve until now. In addition, by providing a sacrificial layer on the EL layer, the damage that the EL layer receives during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0031] While it is difficult to reduce the spacing between adjacent light-emitting devices to less than 10 μm using, for example, a metal mask formation method, the above method allows for narrowing the spacing to 8 μm or less, 6 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, or even 1 μm or less. Furthermore, by using, for example, an exposure apparatus for LSIs, the spacing can be narrowed to 500 nm or less, 200 nm or less, 100 nm or less, and even 50 nm or less.

[0032] Furthermore, the pattern (or processing size) of the EL layer itself can be made significantly smaller compared to when a metal mask is used. Also, for example, when a metal mask is used to create different EL layers, variations in thickness occur between the center and edges of the EL layer, resulting in a smaller effective area usable as an emitting region relative to the area of ​​the EL layer. On the other hand, with the above manufacturing method, a pattern is formed by processing a film deposited to a uniform thickness, so the thickness can be made uniform within the pattern, and even with a fine pattern, almost the entire area can be used as an emitting region. Therefore, it is possible to manufacture a display device that combines high resolution and a high aperture ratio.

[0033] Furthermore, in light-emitting devices that emit white light, it is not necessary to form all the layers constituting the EL layer in an island-like manner; some layers can be deposited in the same process. In a method for manufacturing a display device according to one aspect of the present invention, after forming some of the layers constituting the EL layer in an island-like manner for each pixel, the sacrificial layer can be removed, and the remaining layers constituting the EL layer (e.g., the carrier injection layer) and the common electrode (also called the upper electrode) can be formed in common.

[0034] On the other hand, the carrier injection layer is often a relatively conductive layer within the light-emitting device. Therefore, there is a risk of a short circuit occurring in the light-emitting device if the carrier injection layer comes into contact with the side surface of the island-shaped EL layer. Furthermore, even when the carrier injection layer is provided in an island shape and only a common electrode is formed in common between the light-emitting devices, there is a risk of a short circuit occurring in the light-emitting device if the common electrode comes into contact with the side surface of the island-shaped EL layer or the side surface of the pixel electrode.

[0035] Therefore, in one embodiment of the present invention, a display device is configured to have a side wall-shaped insulator in contact with the side surface of the island-shaped EL layer, and a dam-shaped insulator covering the ends of the island-shaped pixel electrodes. This prevents the island-shaped EL layer from coming into contact with the carrier injection layer or the common electrode. Consequently, short circuits in the light-emitting device can be suppressed, and the reliability of the light-emitting device can be improved.

[0036] [Example configuration of a light-emitting device] Here, we will explain examples of the configuration of the light-emitting device and the colored layer using Figures 2 and 3.

[0037] Figure 2A shows a schematic cross-sectional view of the display device 500. The display device 500 has multiple light-emitting devices 550W that emit white light, and on each light-emitting device 550W, a colored layer 545R that transmits red light, a colored layer 545G that transmits green light, or a colored layer 545B that transmits blue light is provided. Here, it is preferable that the colored layers 545R, 545G, and 545B are provided on the light-emitting device 550W via a protective layer 540.

[0038] The light-emitting device 550W has a configuration in which two light-emitting units (light-emitting unit 512Q_1, light-emitting unit 512Q_2) are stacked between a pair of electrodes (electrode 501, electrode 502) with an intermediate layer 531 in between.

[0039] Electrode 501 functions as a pixel electrode and is provided for each light-emitting device. Electrode 502 functions as a common electrode and is provided in common to multiple light-emitting devices.

[0040] The light-emitting unit 512Q_1 has layers 521, 522, light-emitting layer 523Q_1, layer 524, etc. The light-emitting unit 512Q_2 has layers 522, light-emitting layer 523Q_2, layer 524, etc. The light-emitting device 550W has layers 525, etc. between the light-emitting unit 512Q_2 and the electrode 502. Note that layer 525 can also be considered as part of the light-emitting unit 512Q_2.

[0041] Layer 521 includes, for example, a layer containing a material with high hole injection capabilities (hole injection layer). Layer 522 includes, for example, a layer containing a material with high hole transport capabilities (hole transport layer). Layer 524 includes, for example, a layer containing a material with high electron transport capabilities (electron transport layer). Layer 525 includes, for example, a layer containing a material with high electron injection capabilities (electron injection layer).

[0042] Alternatively, the configuration may include layer 521 having an electron injection layer, layer 522 having an electron transport layer, layer 524 having a hole transport layer, and layer 525 having a hole injection layer.

[0043] In Figure 2A, layers 521 and 522 are shown separately, but the design is not limited to this. For example, if layer 521 has the functions of both a hole injection layer and a hole transport layer, or if layer 521 has the functions of both an electron injection layer and an electron transport layer, layer 522 may be omitted.

[0044] Furthermore, the intermediate layer 531 has the function of injecting electrons into one of the light-emitting units 512Q_1 and 512Q_2 and holes into the other when a voltage is applied between the electrodes 501 and 502. The intermediate layer 531 can also be called a charge generation layer.

[0045] As the intermediate layer 531, for example, a material applicable to the electron injection layer, such as lithium fluoride, can be suitably used. Alternatively, as the intermediate layer, a material applicable to the hole injection layer can be suitably used. Furthermore, the intermediate layer can be a layer containing a material with high hole transport properties (hole transport material) and an acceptor material (electron-accepting material). Alternatively, the intermediate layer can be a layer containing a material with high electron transport properties (electron-transport material) and a donor material. By forming an intermediate layer having such a layer, it is possible to suppress the increase in driving voltage when light-emitting units are stacked.

[0046] By making the emission colors of the emission layer 523Q_1 and the emission layer 523Q_2 of the light-emitting device 550W complementary, the light-emitting device 550W can be made into a light-emitting device that emits white light. Preferably, the emission layers 523Q_1 and 523Q_2 contain light-emitting materials that emit light such as R (red), G (green), B (blue), Y (yellow), and O (orange), respectively. Alternatively, it is preferable that the emission of light from the light-emitting materials in the emission layers 523Q_1 and 523Q_2 contains spectral components of two or more colors from R, G, and B.

[0047] Here, we will explain an example of the combination of light-emitting colors of the light-emitting layers of each light-emitting unit that can be used in the 550W light-emitting device.

[0048] For example, if a 550W light-emitting device has two light-emitting units, a 550W light-emitting device that emits white light can be obtained by emitting red and green light from one unit and blue light from the other unit. Alternatively, a 550W light-emitting device that emits white light can be obtained by emitting yellow or orange light from one unit and blue light from the other unit.

[0049] Furthermore, for example, if the light-emitting device 550W has three light-emitting units, a light-emitting device 550W that emits white light can be obtained by obtaining red light from one of the light-emitting units, green light from another light-emitting unit, and blue light from the remaining light-emitting unit. Alternatively, a blue light-emitting layer can be used in the first light-emitting unit, a yellow, yellow-green, or green light-emitting layer in the second light-emitting unit, and a blue light-emitting layer in the third light-emitting unit. Alternatively, a blue light-emitting layer can be used in the first light-emitting unit, a laminated structure can be used in the second light-emitting unit consisting of a red light-emitting layer and a yellow, yellow-green, or green light-emitting layer, and a blue light-emitting layer in the third light-emitting unit.

[0050] Furthermore, for example, if the 550W light-emitting device has four light-emitting units, a blue light-emitting layer can be used in the first light-emitting unit, a red light-emitting layer in one of the second and third light-emitting units, a yellow, yellow-green, or green light-emitting layer in the other, and a blue light-emitting layer in the fourth light-emitting unit.

[0051] By providing a colored layer 545R, a colored layer 545G, or a colored layer 545B on such a white-emitting light-emitting device 550W, red light emission, green light emission, or blue light emission can be performed for each pixel, enabling full-color display. While Figure 2 and other figures show an example where a colored layer 545R transmits red light, a colored layer 545G transmits green light, and a colored layer 545B transmits blue light, the present invention is not limited to this. The visible light transmitted by the colored layers should consist of at least two or more different colors of visible light, such as red, green, blue, cyan, magenta, or yellow, which can be appropriately selected.

[0052] Therefore, even if layers 521, 522, 524, 525, light-emitting layer 523Q_1, and light-emitting layer 523Q_2 have the same configuration (material, film thickness, etc.) for each color pixel, full-color display can be achieved by appropriately providing a colored layer. Thus, a display device according to one aspect of the present invention does not require the creation of a different light-emitting device for each pixel, thus simplifying the manufacturing process and reducing manufacturing costs. However, the present invention is not limited thereto, and one or more of layers 521, 522, 524, 525, light-emitting layer 523Q_1, and light-emitting layer 523Q_2 can have different configurations depending on the pixel.

[0053] In this specification, a configuration in which multiple light-emitting units are connected in series via an intermediate layer 531, such as the light-emitting device 550W, is called a tandem structure. On the other hand, a configuration in which one light-emitting unit is located between a pair of electrodes is called a single structure. In this specification, the term "tandem structure" is used, but it is not limited to this, and for example, a tandem structure may also be called a stacked structure. By using a tandem structure, a light-emitting device capable of high-brightness emission can be made. Furthermore, compared to a single structure, a tandem structure can reduce the current required to obtain the same brightness, thereby reducing the power consumption of the display device and improving its reliability.

[0054] In Figure 2A, the light-emitting unit 512Q_1, the intermediate layer 531, the light-emitting unit 512Q_2, and the layer 525 can be formed as island-like layers.

[0055] Figure 2B shows a modified version of the display device 500 shown in Figure 2A. The display device 500 shown in Figure 2B is an example in which layer 525 is provided in common among each light-emitting device, similar to the electrode 502. In this case, layer 525 can be called a common layer. By providing one or more common layers to multiple light-emitting devices in this way, the manufacturing process can be simplified, and thus manufacturing costs can be reduced. There are no particular limitations on the common layer. For example, one or more layers from hole injection layers, hole transport layers, light-emitting layers, electron transport layers, and electron injection layers can be used as a common layer. For example, a hole injection layer and a hole transport layer may be provided in common among each light-emitting device.

[0056] The display device 500 shown in Figure 3A is an example where the light-emitting device 550W has a configuration in which three light-emitting units are stacked. In Figure 3A, the light-emitting device 550W has a light-emitting unit 512Q_3 stacked on top of a light-emitting unit 512Q_2 via an intermediate layer 531. The light-emitting unit 512Q_3 has layers 522, light-emitting layer 523Q_3, layer 524, etc.

[0057] When applying a tandem structure to a light-emitting device, the number of light-emitting units is not particularly limited and can be two or more.

[0058] Figure 3B shows an example where n light-emitting units (where n is an integer greater than or equal to 2) are stacked.

[0059] In this way, by increasing the number of stacked light-emitting units, the brightness obtained from the light-emitting device with the same amount of current can be increased in proportion to the number of stacks. Furthermore, by increasing the number of stacked light-emitting units, the current required to obtain the same brightness can be reduced, thus reducing the power consumption of the light-emitting device in proportion to the number of stacks.

[0060] In addition, the light-emitting material of the light-emitting layer in the display device 500 is not particularly limited. For example, in the display device 500 shown in Figure 2A, the light-emitting layer 523Q_1 of the light-emitting unit 512Q_1 may have a phosphorescent material, and the light-emitting layer 523Q_2 of the light-emitting unit 512Q_2 may have a fluorescent material. Alternatively, the light-emitting layer 523Q_1 of the light-emitting unit 512Q_1 may have a fluorescent material, and the light-emitting layer 523Q_2 of the light-emitting unit 512Q_2 may have a phosphorescent material.

[0061] The configuration of the light-emitting unit is not limited to the above. For example, in the display device 500 shown in Figure 2A, the light-emitting layer 523Q_1 of the light-emitting unit 512Q_1 may have a TADF material, and the light-emitting layer 523Q_2 of the light-emitting unit 512Q_2 may have either a fluorescent material or a phosphorescent material. By using different light-emitting materials in this way, for example, by combining a highly reliable light-emitting material with a light-emitting material with high luminous efficiency, it is possible to compensate for the shortcomings of each and create a display device that improves both reliability and luminous efficiency.

[0062] Furthermore, in one embodiment of the present invention, the display device may be configured such that all light-emitting layers are made of fluorescent material, or so may be configured such that all light-emitting layers are made of phosphorescent material.

[0063] [Example of a display device configuration] Next, an embodiment of the present invention will be described with reference to Figures 1A and 1B.

[0064] A display device according to one aspect of the present invention may be a top-emission type that emits light in the direction opposite to the substrate on which the light-emitting device is formed, a bottom-emission type that emits light toward the substrate on which the light-emitting device is formed, or a dual-emission type that emits light on both sides.

[0065] Figure 1A shows a top view (which can also be called a plan view) of the display device 100. The display device 100 has a display unit in which a plurality of pixels 110 are arranged in a matrix, and a connection unit 140 outside the display unit. One pixel 110 is composed of three subpixels: subpixels 110a, 110b, and 110c.

[0066] There are no particular limitations on the arrangement of subpixels, and various methods can be applied. Examples of subpixel arrangements include stripe arrangements, S-stripe arrangements, matrix arrangements, delta arrangements, Bayer arrangements, and pentile arrangements. Pixel 110 shown in Figure 1A uses a stripe arrangement.

[0067] Furthermore, the top surface shape of a sub-pixel can be, for example, a polygon such as a triangle, quadrilateral (including rectangles and squares), or pentagon, or a polygon with rounded corners, or an ellipse or a circle. Here, the top surface shape of a sub-pixel corresponds to the top surface shape of the light-emitting region of the light-emitting device.

[0068] In this embodiment, sub-pixels 110a, 110b, and 110c have light-emitting devices that emit white light, and each sub-pixel emits light of a different color due to the colored layers 125a, 125b, and 125c (hereinafter sometimes collectively referred to as the colored layer 125) provided on them. For example, sub-pixels 110a, 110b, and 110c correspond to sub-pixels having a colored layer 545R, sub-pixels having a colored layer 545G, and sub-pixels having a colored layer 545B, as shown in Figure 2A, etc.

[0069] Figure 1A shows an example where the connection portion 140 is located below the display portion in a top view (which can also be called a plan view), but it is not particularly limited. The connection portion 140 only needs to be provided at least one location on the top, right, left, or bottom of the display portion in a top view, and may be provided so as to surround all four sides of the display portion. Also, there may be one or more connection portions 140.

[0070] Figure 1B shows cross-sectional views between the dashed lines X1-X2, Y1-Y2, and Y3-Y4 in Figure 1A.

[0071] As shown in Figure 1B, the display device 100 has light-emitting devices 130a, 130b, and 130c (hereinafter sometimes collectively referred to as light-emitting devices 130) provided on a layer 101 containing transistors, and a protective layer 131 is provided to cover these light-emitting devices. Here, an insulator 124 is provided on the sides of the light-emitting devices 130a, 130b, and 130c. In addition, colored layers 125a, 125b, and 125c are provided on the protective layer 131. Furthermore, a substrate 120 is bonded on top of that by a resin layer 122.

[0072] For example, the layer 101 containing transistors can be a laminated structure in which multiple transistors are provided on a substrate and an insulating layer is provided to cover these transistors. An example of the configuration of the layer 101 containing transistors will be described later in Embodiment 2.

[0073] The light-emitting devices 130a, 130b, and 130c preferably emit white (W) light. By providing colored layers 125a, 125b, and 125c on these that transmit light of different colors, sub-pixels 110a, 110b, and 110c that emit light of different colors can be formed.

[0074] The light-emitting device has an EL layer between a pair of electrodes. In this specification, one of the pair of electrodes may be referred to as the pixel electrode and the other as the common electrode.

[0075] In a light-emitting device, one electrode functions as the anode and the other as the cathode. The following explanation uses the example where the pixel electrode functions as the anode and the common electrode functions as the cathode.

[0076] Light-emitting device 130a includes a pixel electrode 111a on a layer 101 containing a transistor, a first layer 113 on the pixel electrode 111a, a second layer 114 on the first layer 113, and a common electrode 115 on the second layer 114. The first layer 113 and the second layer 114 can be collectively referred to as the EL layer. Light-emitting device 130b differs from light-emitting device 130a in that it has a pixel electrode 111b instead of a pixel electrode 111a. Light-emitting device 130c differs from light-emitting device 130a in that it has a pixel electrode 111c instead of a pixel electrode 111a. Hereinafter, the pixel electrodes 111a, 111b, and 111c may be collectively referred to as the pixel electrode 111.

[0077] The first layer 113 includes a first light-emitting unit 192 on the pixel electrode 111a, an intermediate layer 191 on the first light-emitting unit 192, and a second light-emitting unit 194 on the intermediate layer 191. For example, the first light-emitting unit 192 includes a first hole injection layer 181a on the pixel electrode 111a, a first hole transport layer 182a on the first hole injection layer 181a, a first light-emitting layer 183a on the first hole transport layer 182a, and a first electron transport layer 184a on the first light-emitting layer 183a. Also, for example, the second light-emitting unit 194 includes a second hole transport layer 182b on the intermediate layer 191, a second light-emitting layer 183b on the second hole transport layer 182b, and a second electron transport layer 184b on the second light-emitting layer 183b.

[0078] The first light-emitting unit 192, the intermediate layer 191, and the second light-emitting unit 194 can each be configured in the same way as, for example, the light-emitting unit 512Q_1, the intermediate layer 531, and the light-emitting unit 512Q_2 shown in Figure 2A. That is, the first light-emitting unit 192 can have layers 521, 522, light-emitting layers 523Q_1, 524, etc. Thus, the first hole injection layer 181a corresponds to layer 521, the first hole transport layer 182a corresponds to layer 522, the first light-emitting layer 183a corresponds to light-emitting layer 523Q_1, and the first electron transport layer 184a corresponds to layer 524. The second light-emitting unit 194 can also have layers 522, light-emitting layers 523Q_2, 524, etc. Therefore, the second hole transport layer 182b corresponds to layer 522, the second light-emitting layer 183b corresponds to light-emitting layer 523Q_2, and the second electron transport layer 184b corresponds to layer 524.

[0079] The second layer 114 is a layer common to the light-emitting devices 130a to 130c. The second layer 114 may, for example, have an electron injection layer. Alternatively, the second layer 114 may have an electron transport layer and an electron injection layer laminated together.

[0080] The common electrode 115 is electrically connected to the conductive layer 123 provided on the connection portion 140. As a result, the same potential is supplied to the common electrode 115 of each color light-emitting device.

[0081] Of the pixel electrodes and common electrodes, the electrode that extracts light should preferably use a conductive film that transmits visible light and infrared light. Furthermore, it is preferable to use a conductive film that reflects visible light and infrared light on the electrode that does not extract light.

[0082] As materials for forming the pair of electrodes (pixel electrode and common electrode) of a light-emitting device, metals, alloys, electrically conductive compounds, and mixtures thereof can be used as appropriate. Specifically, examples include indium tin oxide (In-Sn oxide, also called ITO), In-Si-Sn oxide (also called ITSO), indium zinc oxide (In-Zn oxide), In-W-Zn oxide, aluminum-containing alloys such as aluminum, magnesium, nickel, and lanthanum alloys (Al-Ni-La), as well as silver-containing alloys such as silver-magnesium alloys and silver-palladium-copper alloys (Ag-Pd-Cu, also written as APC). In addition, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys containing these in appropriate combinations can also be used. Furthermore, elements belonging to Group 1 or Group 2 of the periodic table not exemplified above (e.g., lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these in appropriate combinations, graphene, etc., can also be used. Furthermore, the above-mentioned metals, alloys, electrically conductive compounds, and mixtures thereof may be appropriately stacked to form a pair of electrodes (pixel electrodes and common electrodes) for a light-emitting device.

[0083] It is preferable that the light-emitting device has a microcavity structure. Therefore, it is preferable that one of the pair of electrodes in the light-emitting device has an electrode that is transparent to and reflective to visible light (a semi-transmissive / semi-reflective electrode), and the other has an electrode that is reflective to visible light (a reflective electrode). By having a microcavity structure in the light-emitting device, the light emitted from the light-emitting layer can be resonated between the two electrodes, thereby strengthening the light emitted from the light-emitting device.

[0084] Furthermore, semi-transmissive / semi-reflective electrodes can have a laminated structure consisting of a reflective electrode and an electrode that transmits visible light (also called a transparent electrode).

[0085] The light transmittance of the transparent electrode shall be 40% or more. For example, it is preferable to use an electrode in the light-emitting device that has a transmittance of 40% or more for visible light (light with a wavelength of 400 nm or more and less than 750 nm). The visible light reflectance of the semi-transparent / semi-reflective electrode shall be 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes shall be 1 × 10⁻⁶ -2 It is preferable that the transmittance or reflectance of these electrodes to near-infrared light (light with a wavelength of 750 nm to 1300 nm) satisfies the above numerical range, similar to the transmittance or reflectance of visible light.

[0086] In the first layer 113, the first light-emitting unit 192 and the second light-emitting unit 194 each have a light-emitting layer. It is preferable to apply a configuration in which white light emission is obtained by combining the light from the light-emitting layers of multiple light-emitting units. The first light-emitting unit 192 and the second light-emitting unit 194 may each have one or more light-emitting layers.

[0087] The luminescent layer is a layer containing a luminescent material. The luminescent layer may contain one or more types of luminescent materials. Suitable luminescent materials include those exhibiting colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red. Furthermore, materials emitting near-infrared light may also be used as luminescent materials.

[0088] Examples of luminescent materials include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence materials, and quantum dot materials.

[0089] 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.

[0090] Examples of phosphorescent materials include organometallic complexes (especially iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton; organometallic complexes (especially iridium complexes) using phenylpyridine derivatives having electron-withdrawing groups as ligands; platinum complexes; and rare earth metal complexes.

[0091] The light-emitting layer may contain one or more types of organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). One or more of these organic compounds may be hole-transporting materials and / or electron-transporting materials. Alternatively, one or more of these organic compounds may be bipolar materials or TADF materials.

[0092] The light-emitting layer preferably comprises, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that readily forms an excitation complex. This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excitation complex to the light-emitting substance (phosphorescent material). By selecting a combination that forms an excitation complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the light-emitting substance, energy transfer becomes smoother, and light emission can be obtained efficiently. This configuration simultaneously achieves high efficiency, low-voltage operation, and a long lifespan for the light-emitting device.

[0093] The first layer 113 may further include layers other than the light-emitting layer, such as a material with high hole injection properties, a material with high hole transport properties, a hole-blocking material, a material with high electron transport properties, a material with high electron injection properties, an electron-blocking material, or a bipolar material (a material with high electron transport and hole transport properties).

[0094] The light-emitting device may use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-emitting device can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0095] For example, the first layer 113 may have one or more of the following: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0096] The second layer 114 may have one or more of the following: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer. For example, when the pixel electrodes 111a, 111b, and 111c function as anodes and the common electrode 115 functions as a cathode, it is preferable that the second layer 114 has an electron injection layer.

[0097] The hole injection layer is a layer that injects holes from the anode into the hole transport layer, and is a layer containing a material with high hole injection capabilities. Examples of materials with high hole injection capabilities include aromatic amine compounds and composite materials containing hole transport materials and acceptor materials (electron-accepting materials).

[0098] In a light-emitting device, the hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light-emitting layer. The hole transport layer is a layer containing a hole-transporting material. The hole-transporting material is 1 × 10⁻¹⁶ -6 cm 2Materials having a hole mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher hole transport capabilities than electron transport. Preferred hole transport materials include π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, furan derivatives, etc.) and aromatic amines (compounds having an aromatic amine skeleton), which are materials with high hole transport capabilities.

[0099] In a light-emitting device, the electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light-emitting layer. The electron transport layer is a layer containing an electron-transporting material. The electron-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having an electron mobility of 1 / Vs or higher are preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes. Examples of electron-transporting materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds, which are materials with high electron transport capabilities.

[0100] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer, and is a layer containing a material with high electron injection capabilities. Alkali metals, alkaline earth metals, or compounds thereof can be used as materials with high electron injection capabilities. Composite materials containing both electron transport materials and donor materials (electron-donating materials) can also be used as materials with high electron injection capabilities.

[0101] Examples of electron injection layers include lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-(quinolinolato)lithium (abbreviated as Liq), 2-(2-pyridyl)phenolate (abbreviated as LiPP), 2-(2-pyridyl)-3-pyridinolatritium (abbreviated as LiPPy), 4-phenyl-2-(2-pyridyl)phenolate (abbreviated as LiPPP), and lithium oxide (LiO2). x ), alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used.

[0102] Alternatively, an electron-transporting material may be used as the electron injection layer. For example, a compound having a lone pair of electrons and an electron-deficient heteroaromatic ring can be used as the electron-transporting material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), or a triazine ring can be used.

[0103] Furthermore, it is preferable that the lowest unoccupied molecular orbital (LUMO) of an organic compound containing a lone pair of electrons is between -3.6 eV and -2.3 eV. In addition, the highest occupied molecular orbital (HOMO) level and LUMO level of an organic compound can generally be estimated by methods such as cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy.

[0104] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz) can be used in organic compounds containing lone pairs of electrons. Compared to BPhen, NBPhen has a higher glass transition temperature (Tg) and superior heat resistance.

[0105] Furthermore, a material made by mixing multiple types of substances (also called a composite material) can be used for the first layer 113. Specifically, a composite material containing an alkali metal, alkali metal compound, or alkali metal complex and an electron-transporting material can be used for the first layer 113. It is more preferable that the HOMO level of the electron-transporting material is -6.0 eV or higher.

[0106] Alternatively, a composite material of an acceptor material and a hole transporter material can be used for the first layer 113. Specifically, a composite material of an acceptor material and a material having a relatively deep HOMO level between -5.7 eV and -5.4 eV can be used for the first layer 113. By using this composite material for the first layer 113, the reliability of the light-emitting device can be improved.

[0107] In this specification, a light-emitting device using the above-mentioned composite material in the first layer 113 may be referred to as a Recombination-Site Tailoring Injection structure (ReSTI structure).

[0108] It is preferable to have a protective layer 131 on the light-emitting devices 130a, 130b, and 130c. Providing the protective layer 131 can improve the reliability of the light-emitting devices.

[0109] The conductivity of the protective layer 131 is not required. The protective layer 131 can be at least one of an insulating film, a semiconductor film, and a conductive film.

[0110] The protective layer 131 has an inorganic film or inorganic insulating film, which prevents oxidation of the common electrode 115 and suppresses the intrusion of impurities (such as moisture and oxygen) into the light-emitting devices 130a, 130b, and 130c. This suppresses the degradation of the light-emitting devices and improves the reliability of the display device.

[0111] For the protective layer 131, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxidative nitride insulating films include silicon oxide nitride films and aluminum oxide nitride films. Examples of nitride oxide insulating films include silicon oxide nitride films and aluminum oxide nitride films.

[0112] In this specification, the term "oxide-nitride" refers to a material in which the oxygen content is greater than the nitrogen content, and the term "nitride oxide" refers to a material in which the nitrogen content is greater than the oxygen content. For example, when "silicon oxynitride" is written, it refers to a material in which the oxygen content is greater than the nitrogen content, and when "silicon nitride oxide" is written, it refers to a material in which the nitrogen content is greater than the oxygen content.

[0113] The protective layer 131 preferably has a nitride insulating film or a nitride oxide insulating film, and more preferably has a nitride insulating film.

[0114] Furthermore, the protective layer 131 may also be an inorganic film containing In-Sn oxide (also known as ITO), In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or indium gallium zinc oxide (In-Ga-Zn oxide, also known as IGZO). The inorganic film is preferably highly resistive, and more specifically, it is preferably more resistive than the common electrode 115. The inorganic film may also contain nitrogen. For example, when the common electrode 115 is made of a metal that is easily degraded by impurities (moisture, oxygen, etc.), such as a silver-magnesium alloy, In-Ga-Zn oxide or the like can be used as the protective layer 131.

[0115] When the light emitted from a light-emitting device is extracted via a protective layer 131, it is preferable that the protective layer 131 has high transmittance to visible light. For example, ITO, IGZO, and aluminum oxide are preferred because they are inorganic materials with high transmittance to visible light.

[0116] As the protective layer 131, for example, a laminated structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a laminated structure of an aluminum oxide film and an IGZO film on the aluminum oxide film can be used. By using such a laminated structure, it is possible to suppress impurities (water, oxygen, etc.) that penetrate to the EL layer.

[0117] Furthermore, the protective layer 131 may have an organic film. For example, the protective layer 131 may have both an organic film and an inorganic film.

[0118] A colored layer 125 (colored layer 125a, colored layer 125b, and colored layer 125c) is provided on the protective layer 131. Colored layer 125a has a region that overlaps with the light-emitting device 130a, colored layer 125b has a region that overlaps with the light-emitting device 130b, and colored layer 125c has a region that overlaps with the light-emitting device 130c. Colored layers 125a, 125b, and 125c each have a region that overlaps with at least the light-emitting layer of their respective light-emitting devices 130.

[0119] The colored layers 125a, 125b, and 125c have the function of transmitting light of different colors from each other. For example, colored layer 125a has the function of transmitting red light, colored layer 125b has the function of transmitting green light, and colored layer 125c has the function of transmitting blue light. As a result, the display device 100 can display in full color. In addition, colored layers 125a, 125b, and 125c may also have the function of transmitting cyan, magenta, and yellow light.

[0120] Here, it is preferable that adjacent colored layers 125 have overlapping regions. Specifically, it is preferable that adjacent colored layers 125 have overlapping regions in regions that do not overlap with the light-emitting device 130. By overlapping colored layers 125 that transmit light of different colors, the colored layers 125 can function as light-shielding layers in the overlapping regions. Therefore, it is possible to suppress the leakage of light emitted by the light-emitting device 130 to adjacent sub-pixels. For example, it is possible to suppress the incidence of light emitted by the light-emitting device 130a that overlaps with the colored layer 125a onto the colored layer 125b. Therefore, the contrast of the image displayed on the display device can be increased, and a display device with high display quality can be realized.

[0121] It is not necessary for adjacent colored layers 125 to have overlapping regions. In this case, it is preferable to provide a light-shielding layer in a region that does not overlap with the light-emitting device 130. The light-shielding layer can be provided, for example, on the side of the substrate 120 facing the resin layer 122. Alternatively, the colored layer 125 may be provided on the side of the substrate 120 facing the resin layer 122.

[0122] Furthermore, by forming the colored layer 125 on the protective layer 131, the alignment of each light-emitting device 130 and each colored layer 125 is easier compared to the case where the colored layer 125 is formed on the substrate 120, enabling the realization of an extremely high-definition display device.

[0123] Each end of the pixel electrodes 111a, 111b, and 111c is covered by an insulator 121. The insulator 121 can also be called a bank, partition, barrier, or ridge. By providing such an insulator 121, it is possible to prevent the second layer 114 or the common electrode 115 from coming into contact with the pixel electrodes 111a, 111b, and 111c, thereby suppressing a short circuit in the light-emitting device 130.

[0124] Furthermore, the insulator 121 has openings above each of the pixel electrodes 111a, 111b, and 111c, and at these openings, the pixel electrodes 111a, 111b, and 111c are in contact with the lower part of the first light-emitting unit 192 (for example, the first hole injection layer 181a). In other words, at or near the ends of each of the pixel electrodes 111a, 111b, and 111c, a portion of the insulator 121 is provided between the pixel electrode 111a, 111b, or 111c and the first hole injection layer 181a.

[0125] The insulator 121 can have a single-layer structure or a multilayer structure using one or both of an inorganic insulating film and an organic insulating film.

[0126] Examples of organic insulating materials that can be used for the insulator 121 include acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyimidoamide resin, polysiloxane resin, benzocyclobutene resin, and phenolic resin. Furthermore, as the inorganic insulating film that can be used for the insulator 121, the same inorganic insulating film that can be used for the protective layer 131 can be used.

[0127] When an inorganic insulating film is used as the insulator 121 covering the ends of the pixel electrodes, impurities are less likely to enter the light-emitting device compared to when an organic insulating film is used, thereby improving the reliability of the light-emitting device. When an organic insulating film is used as the insulator 121 covering the ends of the pixel electrodes, the step coverage is higher compared to when an inorganic insulating film is used, and it is less affected by the shape of the pixel electrodes. Therefore, short circuits in the light-emitting device can be prevented. Specifically, when an organic insulating film is used as the insulator 121, the shape of the insulator 121 can be processed into a tapered shape or the like. In this specification, a tapered shape refers to a shape in which at least a part of the side surface of the structure is inclined with respect to the substrate surface. For example, it is preferable to have a region in which the angle between the inclined side surface and the substrate surface (also called the taper angle) is less than 90°.

[0128] The insulator 124 is provided on the insulator 121, in contact with at least a portion of the side surface of the light-emitting device 130. In this case, it is preferable that the insulator 124 is in contact with at least a portion of the side surface of the first light-emitting unit 192, the side surface of the intermediate layer 191, and the side surface of the second light-emitting unit 194. For example, as shown in Figure 1B, the insulator 124 can be configured to be in contact with the side surface of the first hole injection layer 181a, the side surface of the first hole transport layer 182a, the side surface of the first light-emitting layer 183a, the side surface of the first electron transport layer 184a, the side surface of the intermediate layer 191, the side surface of the second hole transport layer 182b, the side surface of the second light-emitting layer 183b, and the side surface of the second electron transport layer 184b. In this way, by configuring the light-emitting device so that at least a portion of its side surface is covered by the insulator 124, it is possible to suppress contact between the second layer 114 and any of the sides of the first light-emitting unit 192, the intermediate layer 191, and the second light-emitting unit 194. As a result, a short circuit in the light-emitting device 130 can be suppressed. The insulator 124 can also be called a side wall, a side wall protective layer, or a side wall insulating film.

[0129] Figure 1B shows an example in which the insulator 124 has a two-layer structure consisting of an insulator 124a and an insulator 124b on top of the insulator 124a. Preferably, the side surface of the insulator 124a is in contact with at least a portion of the side surface of the light-emitting device 130, and the bottom surface of the insulator 124a is in contact with at least a portion of the insulator 121. Also, preferably, the side surface and bottom surface of the insulator 124b are in contact with at least a portion of the insulator 124a.

[0130] Furthermore, the thickness of the insulator 124b in the direction perpendicular to the substrate surface of the substrate 120 can be made thicker than the thickness of the insulator 124b in the direction parallel to the substrate surface of the substrate 120. Also, the shape of the upper end of the insulator 124b can be rounded. Making the shape of the upper end of the insulator 124b rounded is preferable because it improves the coverage of the second layer 114, the common electrode 115, and the protective layer 131.

[0131] For insulators 124a and 124b, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxidative nitride insulating films include silicon oxide nitride films and aluminum oxide nitride films. Examples of nitride oxide insulating films include silicon oxide nitride films and aluminum oxide nitride films.

[0132] The insulators 124a and 124b can be formed by various film deposition methods, such as sputtering, vapor deposition (including vacuum deposition), CVD, and ALD. In particular, since the ALD method causes little damage to the layer being formed, it is preferable to deposit the insulator 124a, which is in direct contact with the first light-emitting unit 192, the intermediate layer 191, and the second light-emitting unit 194, using the ALD method. Furthermore, it is preferable to deposit the insulator 124b using a sputtering method or the like, as this can increase productivity.

[0133] For example, an aluminum oxide film deposited by the ALD method can be used for the insulator 124a, and a silicon nitride film deposited by the sputtering method can be used for the insulator 124b.

[0134] Furthermore, it is preferable that one or both of insulator 124a and insulator 124b function as a barrier insulating film against at least one of water and oxygen. Alternatively, it is preferable that one or both of insulator 124a and insulator 124b have a function to suppress the diffusion of at least one of water and oxygen. Alternatively, it is preferable that one or both of insulator 124a and insulator 124b have a function to capture or fix (also called gettering) at least one of water and oxygen.

[0135] In this specification, a barrier insulating film refers to an insulating film having barrier properties. In this specification, barrier properties refer to the function of suppressing the diffusion of the corresponding substance (also called low permeability). Alternatively, in this specification, barrier properties refer to the function of capturing or fixing the corresponding substance (also called gettering).

[0136] Insulator 124a and insulator 124b, or both, have the function of the barrier insulating film or gettering function described above, thereby suppressing the intrusion of impurities (typically water or oxygen) that can diffuse from the outside into each light-emitting element. This configuration makes it possible to provide a display device with excellent reliability.

[0137] In this specification, devices fabricated using a metal mask or an FMM (Fine Metal Mask, a high-resolution metal mask) may be referred to as MM (Metal Mask) structured devices. Furthermore, in this specification, devices fabricated without using a metal mask or an FMM may be referred to as MML (Metal Maskless) structured devices.

[0138] In this specification, a light-emitting device capable of emitting white light may be referred to as a white light-emitting device. A white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device. Furthermore, a structure in which different light-emitting layers are created or painted for each color of light-emitting device (here, blue (B), green (G), and red (R)) may be referred to as an SBS (Side By Side) structure.

[0139] Furthermore, light-emitting devices can be broadly classified into single-structure and tandem-structure devices. A single-structure device has one light-emitting unit between a pair of electrodes, and it is preferable that this light-emitting unit includes one or more light-emitting layers. To obtain white light emission, one should select light-emitting layers such that the light emitted from each of the two or more layers is complementary in color. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary, a configuration that emits white light as a whole can be obtained. The same applies to light-emitting devices having three or more light-emitting layers.

[0140] A tandem device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, the device should be configured such that the light from the light-emitting layers of the multiple light-emitting units is combined to produce white light emission. The configuration for obtaining white light emission is the same as that for a single-structure device. In a tandem device, it is preferable to provide an intermediate layer, such as a charge-generating layer, between the multiple light-emitting units.

[0141] Furthermore, when comparing the aforementioned white light-emitting devices (single or tandem structure) with light-emitting devices with an SBS structure, white light-emitting devices are preferable because their manufacturing process is simpler than that of SBS structures, which can lead to lower manufacturing costs or higher manufacturing yields.

[0142] The display device of this embodiment can reduce the distance between light-emitting devices. Here, the distance between light-emitting devices can be, for example, the distance between the opposing sides of adjacent pixel electrodes 111. Specifically, the distance between light-emitting devices can be reduced to 8 μm or less, 6 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Furthermore, by using, for example, an exposure apparatus for LSIs, the spacing can be reduced to 500 nm or less, 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 10 nm.

[0143] Figure 1A illustrates an example where sub-pixels 110a, 110b, and 110c are arranged in a stripe pattern; however, the present invention is not limited to this. Below, Figures 4 to 6 illustrate examples of pixel arrangements different from those shown in Figure 1A.

[0144] The pixel 110 shown in Figure 4A has an S-stripe array applied to it. The pixel 110 shown in Figure 4A is composed of three subpixels: subpixels 110a, 110b, and 110c. Here, in a 2x2 subpixel array, subpixels 110b and 110c in the second column are placed in the first and second rows, respectively, while subpixel 110a in the first column is placed across the first and second rows. For example, subpixel 110a could be a blue subpixel, subpixel 110b a red subpixel, and subpixel 110c a green subpixel.

[0145] The pixel 110 shown in Figure 4B includes a sub-pixel 110a with a roughly trapezoidal top surface shape with rounded corners, a sub-pixel 110b with a roughly triangular top surface shape with rounded corners, and a sub-pixel 110c with a roughly square or roughly hexagonal top surface shape with rounded corners. Furthermore, sub-pixel 110a has a larger light-emitting area than sub-pixel 110b. Thus, the shape and size of each sub-pixel can be determined independently. For example, the size of a sub-pixel can be reduced to a level that provides a more reliable light-emitting device. For example, sub-pixel 110a may be a green sub-pixel, sub-pixel 110b a red sub-pixel, and sub-pixel 110c a blue sub-pixel.

[0146] A Pentile array is applied to pixels 128a and 128b shown in Figure 4C. Figure 4C shows an example in which pixels 128a having subpixels 110a and 110b, and pixels 128b having subpixels 110b and 110c are arranged alternately. For example, subpixel 110a may be a blue subpixel, subpixel 110b a green subpixel, and subpixel 110c a red subpixel.

[0147] Pixels 128a and 128b, shown in Figures 4D and 4E, have a delta array applied. Pixel 128a has two subpixels (subpixels 110a and 110b) in the top row (1st row) and one subpixel (subpixel 110c) in the bottom row (2nd row). Pixel 128b has one subpixel (subpixel 110c) in the top row (1st row) and two subpixels (subpixels 110a and 110b) in the bottom row (2nd row).

[0148] Figure 4D shows an example where each subpixel has a roughly square top shape with rounded corners, and Figure 4E shows an example where each subpixel has a circular top shape.

[0149] In photolithography, the finer the pattern being processed, the more significant the effects of light diffraction become. This compromises the fidelity of the transfer of the photomask pattern through exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, patterns with rounded corners are likely to be formed. Consequently, the top surface shape of subpixels may be a polygon with rounded corners, an ellipse, or a circle.

[0150] Furthermore, in a method for manufacturing a display device according to one aspect of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the EL layer material and the curing temperature of the resist material, the curing of the resist film may be insufficient. A resist film that is not sufficiently cured may take a shape that deviates from the desired shape during processing. As a result, the top surface shape of the EL layer may become a polygon with rounded corners, an ellipse, or a circle. For example, if an attempt is made to form a resist mask with a square top surface, a resist mask with a circular top surface may be formed, resulting in a circular top surface shape for the EL layer.

[0151] Furthermore, in order to achieve the desired shape of the upper surface of the EL layer, a technique (OPC (Optical Proximity Correction) technique) may be used to pre-correct the mask pattern so that the design pattern and the transferred pattern match. Specifically, in the OPC technique, a correction pattern is added to the corners of the shape on the mask pattern.

[0152] Furthermore, although Figure 1A shows a configuration with three subpixels, the present invention is not limited to this. A configuration with four or more subpixels is also possible. The pixel 110 shown in Figure 5A is composed of four subpixels: subpixels 110a, 110b, 110c, and 110d. Subpixel 110d also has a light-emitting device 130d that emits white light, similar to subpixels 110a, 110b, and 110c. As shown in Figure 5B, the light-emitting device 130d has a pixel electrode 111d, a first layer 113, a second layer 114, and a common electrode 115. However, unlike subpixels 110a, 110b, and 110c, subpixel 110d does not have a colored layer. With this configuration, for example, sub-pixels 110a, 110b, and 110c can be red, green, and blue sub-pixels, respectively, and sub-pixel 110d can be a white sub-pixel.

[0153] Figure 5A shows an example where one pixel 110 is arranged in a 2x3 grid. Pixel 110 has three subpixels (subpixels 110a, 110b, and 110c) in the top row (row 1) and one subpixel (subpixel 110d) in the bottom row (row 2). In other words, pixel 110 has subpixel 110a in the left column (column 1), subpixel 110b in the middle column (column 2), subpixel 110c in the right column (column 3), and subpixel 110d across these three columns.

[0154] The pixels 110 shown in Figures 6A to 6C are arranged in a stripe pattern. The pixels 110 shown in Figures 6A to 6C are composed of four subpixels: subpixels 110a, 110b, 110c, and 110d. Each subpixel 110a, 110b, 110c, and 110d has a light-emitting device that emits light of a different color. For example, subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and white subpixels, respectively.

[0155] Figure 6A shows an example where each subpixel has a rectangular top surface shape, Figure 6B shows an example where each subpixel has a top surface shape formed by connecting two semicircles and a rectangle, and Figure 6C shows an example where each subpixel has an elliptical top surface shape.

[0156] The pixel 110 shown in Figures 6D to 6F has a matrix array applied to it. The pixel 110 shown in Figures 6D to 6F is composed of four subpixels: subpixels 110a, 110b, 110c, and 110d. Each subpixel 110a, 110b, 110c, and 110d has a light-emitting device that emits light of a different color. For example, subpixels 110a, 110b, 110c, and 110d can be red, green, blue, and white subpixels, respectively.

[0157] Figure 6D shows an example where each subpixel has a square top surface shape, Figure 6E shows an example where each subpixel has a roughly square top surface shape with rounded corners, and Figure 6F shows an example where each subpixel has a circular top surface shape.

[0158] The pixel 110 shown in Figure 6G is composed of six subpixels: subpixel 110a, subpixel 110b, subpixel 110c, subpixel 110d1, subpixel 110d2, and subpixel 110d3. Subpixels 110d1, 110d2, and 110d3 in Figure 6G are obtained by separating subpixel 110d shown in Figure 5A in parallel with subpixels 110a, 110b, and 110c. Here, subpixels 110d1, 110d2, and 110d3 may be configured to be electrically connected to the same transistor in layer 101 which contains the transistor.

[0159] As shown in Figure 6G, the narrow passages formed between the sub-pixels 110a, 110b, 110c, 110d1, 110d2, and 110d3 are formed to cross the display device 100 in the X or Y direction. This makes it easier for debris to flow through these narrow passages during the cleaning process when manufacturing the display device 100, preventing debris generated during the manufacturing process from contaminating the display device.

[0160] Next, a modified example of the cross-sectional shape of the display device 100 will be described using Figures 7 to 9.

[0161] As shown in Figure 7A, recesses may be formed on the upper part of the insulator 121 between adjacent light-emitting devices 130. For example, a first recess may be formed in a region of the insulator 121 that does not overlap with the first layer 113. In this case, the lower surface of the insulator 124 may be in contact with the bottom surface of the first recess. Also, for example, a second recess may be formed in a region within the first recess that does not overlap with the insulator 124. In this case, a part of the second layer 114 may be in contact with the bottom surface of the second recess.

[0162] Furthermore, while Figure 1B shows an example where the second layer 114 extends into the region between adjacent insulators 124, as shown in Figure 7B, a void 133 may be formed in that region.

[0163] The void 133 contains, for example, one or more selected from air, nitrogen, oxygen, carbon dioxide, and Group 18 elements (typically helium, neon, argon, xenon, krypton, etc.).

[0164] Furthermore, if the refractive index of the air gap 133 is lower than that of the second layer 114, the light emitted from the light-emitting device is reflected at the interface between the second layer 114 and the air gap 133. This suppresses the incidence of light emitted from the light-emitting device on adjacent pixels (or sub-pixels). Therefore, since the mixing of light from different pixels can be suppressed, the display quality of the display device can be improved.

[0165] Furthermore, while Figure 1B shows an example in which the insulator 124 has an insulator 124a and an insulator 124b on top of the insulator 124a, as shown in Figure 8A, the insulator 124 may have a single-layer structure. The insulator 124 may be formed using a material that can be used for the insulator 124a or insulator 124b described above.

[0166] Furthermore, while Figure 1B shows an example where the upper end of the insulator 124 roughly coincides with the upper surface of the second electron transport layer 184b, the present invention is not limited to this. For example, as shown in Figure 8B, the upper ends of either or both of the insulators 124a and 124b may protrude beyond the upper surface of the second electron transport layer 184b. With such a configuration, the insulator 124 can cover the side surface of the first layer 113 up to its upper end, thereby further suppressing short circuits in the light-emitting device 130.

[0167] Furthermore, although Figure 1B shows an example in which the colored layers 125a, 125b, and 125c are in contact with the upper surface of the protective layer 131, the present invention is not limited to this. For example, as shown in Figure 9A, a well-flat insulating layer 126 may be provided covering the protective layer 131, and the colored layers 125a, 125b, and 125c may be provided on top of the insulating layer 126. Here, the insulating layer 126 may be, for example, an organic insulating material or an inorganic insulating material that can be used for the insulator 121. Furthermore, a resin layer 122 may be provided on top of the colored layers 125a, 125b, and 125c, and the substrate 120 may be bonded to it.

[0168] Furthermore, as shown in Figure 9B, a configuration may be used in which conductive layers 112a, 112b, and 112c (hereinafter collectively referred to as conductive layer 112) having the function of transmitting visible light are provided on the pixel electrodes 111a, 111b, and 111c. Similarly, in this case, conductive layer 123 will also have a laminated structure of conductive layer 123a and conductive layer 123b.

[0169] As the conductive layer 112, a conductive film that is transparent to visible light as described above can be used. Alternatively, as the conductive layer 112, a film can be used in which the conductive film that reflects visible light is formed to a degree that allows visible light to pass through. Furthermore, by creating a laminated structure of the conductive film and the conductive film that transmits visible light, conductivity and mechanical strength can be increased.

[0170] As shown in Figure 9B, the conductive layer 112 is positioned between the pixel electrode 111 and the first hole injection layer 181a. The conductive layer 112 is located on the pixel electrode 111.

[0171] Furthermore, as shown in Figure 9B, it is preferable that the conductive layers 112 provided on each light-emitting device 130 have different thicknesses for each light-emitting device. For example, if the colored layer 125a transmits red light, the colored layer 125b transmits green light, and the colored layer 125c transmits blue light, then the thickness of conductive layer 112a should be the thickest and the thickness of conductive layer 112c should be the thinnest among the three conductive layers 112. Here, the distance between the upper surface of the pixel electrode 111 and the lower surface of the common electrode 115 in each light-emitting device is largest in the light-emitting device 130 that overlaps with the colored layer 125a and smallest in the light-emitting device 130 that overlaps with the colored layer 125c. By changing the distance between the upper surface of the pixel electrode 111 and the lower surface of the common electrode 115 in each light-emitting device, the optical distance (optical path length) in each light-emitting element can be changed.

[0172] Of the three light-emitting devices, the light-emitting device 130 that overlaps with the colored layer 125a has the longest optical path length, and therefore emits light with the longest wavelength (e.g., red light) being amplified. On the other hand, the light-emitting device 130 that overlaps with the colored layer 125b has the shortest optical path length, and therefore emits light with the shortest wavelength (e.g., blue light) being amplified. The light-emitting device 130 that overlaps with the colored layer 125b emits light with the intermediate wavelength (e.g., green light) being amplified.

[0173] This configuration eliminates the need to create separate light-emitting layers for each subpixel of a different color, allowing for highly accurate color reproduction using light-emitting devices with the same configuration.

[0174] [Examples of methods for manufacturing display devices] Next, an example of a method for manufacturing a display device will be explained using Figures 10 to 13. Figures 10A to 10D show side by side the cross-sectional views between the dashed lines X1 and X2 in Figure 1A, between Y1 and Y2, and between Y3 and Y4. Figures 11 to 13 are similar to Figure 10.

[0175] Thin films (insulating films, semiconductor films, and conductive films, etc.) that constitute display devices can be formed using sputtering, chemical vapor deposition (CVD), vacuum deposition, pulsed laser deposition (PLD), ALD, and other methods. CVD methods include plasma-enhanced CVD (PECVD) and thermal CVD. One type of thermal CVD is metal-organic CVD (MOCVD).

[0176] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife coating, slit coating, roll coating, curtain coating, and knife coating.

[0177] In particular, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet can be used to fabricate light-emitting devices. Examples of vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, as well as chemical vapor deposition (CVD). Functional layers included in the EL layer (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, etc.) can be formed by vapor deposition (vacuum deposition, etc.), coating methods (dip coating, die coating, bar coating, spin coating, spray coating, etc.), and printing methods (inkjet, screen printing, offset printing, flexographic printing, gravure, or microcontact printing, etc.).

[0178] Furthermore, when processing the thin film that constitutes the display device, photolithography or the like can be used. Alternatively, the thin film may be processed by nanoimprint lithography, sandblasting, lift-off lithography, or the like. In addition, island-shaped thin films may be directly formed by a film deposition method using a shielding mask such as a metal mask.

[0179] There are two main methods of photolithography. One method involves forming a resist mask on the thin film to be processed, then processing the thin film by etching or other means, and removing the resist mask. The other method involves forming a photosensitive thin film, then exposing and developing it to process the thin film into the desired shape.

[0180] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture thereof. Other options include ultraviolet light, KrF laser light, or ArF laser light. Exposure may also be performed using immersion lithography. Furthermore, extreme ultraviolet (EUV) light or X-rays may be used as the light source for exposure. An electron beam can also be used instead of the light source. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because it allows for extremely fine processing. Note that when exposure is performed by scanning a beam such as an electron beam, a photomask may not be necessary.

[0181] For etching thin films, methods such as dry etching, wet etching, and sandblasting can be used.

[0182] First, as shown in Figure 10A, pixel electrodes 111a, 111b, 111c, and a conductive layer 123 are formed on the layer 101 containing the transistor. Each pixel electrode is provided on the display section, and the conductive layer 123 is provided on the connection section 140.

[0183] Next, an insulator 121 is formed to cover the ends of the pixel electrodes 111a, 111b, and 111c and the ends of the conductive layer 123.

[0184] Then, as shown in Figure 10B, a first hole injection layer 181A, a first hole transport layer 182A, a first light-emitting layer 183A, a first electron transport layer 184A, an intermediate layer 191A, a second hole transport layer 182B, a second light-emitting layer 183B, and a second electron transport layer 184B are formed in this order on each pixel electrode and on the insulator 121, a first sacrificial layer 118A is formed on the second electron transport layer 184B, and a second sacrificial layer 119A is formed on the first sacrificial layer 118A.

[0185] Figure 10B shows an example in which the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, the second electron transport layer 184B, the first sacrificial layer 118A, and the second sacrificial layer 119A are all provided on the conductive layer 123 in a cross-sectional view between Y1 and Y2, but the invention is not limited to this example.

[0186] For example, the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, the second electron transport layer 184B, and the first sacrificial layer 118A do not have to overlap with the conductive layer 123. Also, the ends of the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B on the connection portion 140 side may be located inward from the ends of the first sacrificial layer 118A and the second sacrificial layer 119A. For example, by using a mask to define the film deposition area (also called an area mask or rough metal mask), the areas to be deposited can be varied between the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B, and the first sacrificial layer 118A and the second sacrificial layer 119A. In one embodiment of the present invention, a light-emitting device is formed using a resist mask, but by combining it with an area mask as described above, a light-emitting device can be manufactured in a relatively simple process.

[0187] The materials that can be used as pixel electrodes are as described above. For forming the pixel electrodes, for example, sputtering or vacuum deposition can be used.

[0188] As described above, the insulator 121 can be a single-layer structure or a multilayer structure using one or both of an inorganic insulating film and an organic insulating film.

[0189] The first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B are layers that later become the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, the first electron transport layer 184a, the intermediate layer 191, the second hole transport layer 182b, the second light-emitting layer 183b, and the second electron transport layer 184b, respectively. Therefore, the configurations applicable to the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, the first electron transport layer 184a, the intermediate layer 191, the second hole transport layer 182b, the second light-emitting layer 183b, and the second electron transport layer 184b described above can be applied accordingly.

[0190] The first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B can each be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating. Furthermore, the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B may each be formed using a premixed material. In this specification, a premixed material refers to a composite material obtained by pre-combining or mixing multiple materials.

[0191] In this embodiment, an example is shown in which the sacrificial layer has a two-layer structure consisting of a first sacrificial layer and a second sacrificial layer, but the sacrificial layer may be a single-layer structure or a laminated structure of three or more layers. For the sacrificial layer, a film with high resistance to the processing conditions of the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B is used, specifically a film with a high etching selectivity ratio.

[0192] For forming the sacrificial layer, methods such as sputtering, ALD (thermal ALD, PEALD), or vacuum deposition can be used. A method that minimizes damage to the EL layer is preferred, and it is preferable to use ALD or vacuum deposition rather than sputtering to form the sacrificial layer.

[0193] It is preferable to use a film that can be removed by wet etching for the sacrificial layer. By using wet etching, compared to using dry etching, it is possible to reduce the damage inflicted on the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B during processing of the sacrificial layer.

[0194] In the manufacturing process of the display device according to this embodiment, it is desirable that the various functional layers constituting the light-emitting device (hole injection layer, hole transport layer, light-emitting layer, active layer, and electron transport layer, etc.) are difficult to process, and that the various sacrificial layers are difficult to process during the processing of the functional layers. It is desirable to select the material and processing method of the sacrificial layers and the processing method of the functional layers taking these factors into consideration.

[0195] As the sacrificial layer, for example, an inorganic film such as a metal film, alloy film, metal oxide film, semiconductor film, or inorganic insulating film can be used.

[0196] The sacrificial layer can be made of metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metallic materials.

[0197] Furthermore, metal oxides such as In-Ga-Zn oxide can be used as the sacrificial layer. For example, an In-Ga-Zn oxide film can be formed as the sacrificial layer using a sputtering method. In addition, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc. can be used. Alternatively, indium tin oxide containing silicon can also be used.

[0198] In addition, element M (where M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) may be used instead of gallium.

[0199] Furthermore, various inorganic insulating films that can be used for the protective layer 131 can be used as the sacrificial layer. In particular, oxide insulating films are preferred because they have higher adhesion to the EL layer compared to nitride insulating films. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used as the sacrificial layer. For example, an aluminum oxide film can be formed as the sacrificial layer using the ALD method. Using the ALD method is preferable because it reduces damage to the substrate (especially the EL layer).

[0200] For example, a laminated structure can be applied as a sacrificial layer, consisting of an In-Ga-Zn oxide film formed by sputtering and an aluminum oxide film formed on the In-Ga-Zn oxide film using ALD. Alternatively, a laminated structure can be applied as a sacrificial layer, consisting of an aluminum oxide film formed by ALD and an In-Ga-Zn oxide film formed on the aluminum oxide film using sputtering. Furthermore, a single-layer structure of an aluminum oxide film formed by ALD can be applied as a sacrificial layer.

[0201] Next, as shown in Figure 10C, a resist mask 190 is formed on the second sacrificial layer 119A. The resist mask can be formed by applying a photosensitive resin (photoresist), exposing it to light, and developing it. The resist mask 190 is positioned to overlap with the pixel electrodes 111a, 111b, and 111c. It is preferable that the resist mask 190 does not overlap with the conductive layer 123.

[0202] Then, as shown in Figure 10D, a portion of the second sacrificial layer 119A is removed using the resist mask 190. This removes the region of the second sacrificial layer 119A that does not overlap with the resist mask 190. Therefore, the second sacrificial layer 119 remains in the position that overlaps with the pixel electrodes 111a, 111b, and 111c. After that, the resist mask 190 is removed.

[0203] Next, as shown in Figure 11A, a portion of the first sacrificial layer 118A is removed using the second sacrificial layer 119. This removes the region of the first sacrificial layer 118A that does not overlap with the second sacrificial layer 119. Therefore, the stacked structure of the first sacrificial layer 118 and the second sacrificial layer 119 remains in the position that overlaps with the pixel electrodes 111a, 111b, and 111c.

[0204] Next, as shown in Figure 11B, the first sacrificial layer 118 and the second sacrificial layer 119 are used to remove a portion of the first hole injection layer 181A, a portion of the first hole transport layer 182A, a portion of the first light-emitting layer 183A, a portion of the first electron transport layer 184A, a portion of the intermediate layer 191A, a portion of the second hole transport layer 182B, a portion of the second light-emitting layer 183B, and a portion of the second electron transport layer 184B. This removes the portions of the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B that do not overlap with the first sacrificial layer 118 and the second sacrificial layer 119. As a result, the conductive layer 123 is exposed. Then, a stacked structure remains on the pixel electrodes 111a, 111b, and 111c, consisting of a first hole injection layer 181a, a first hole transport layer 182a, a first light-emitting layer 183a, a first electron transport layer 184a, an intermediate layer 191, a second hole transport layer 182b, a second light-emitting layer 183b, a second electron transport layer 184b, a first sacrificial layer 118, and a second sacrificial layer 119.

[0205] The laminated structure of the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, and the first electron transport layer 184a may be referred to as the first light-emitting unit 192. The laminated structure of the second hole transport layer 182b, the second light-emitting layer 183b, and the second electron transport layer 184b may be referred to as the second light-emitting unit 194. The laminated structure of the first light-emitting unit 192, the intermediate layer 191, and the second light-emitting unit 194 may be referred to as the first layer 113.

[0206] The first sacrificial layer 118A and the second sacrificial layer 119A can be processed by wet etching or dry etching, respectively. It is preferable to process the first sacrificial layer 118A and the second sacrificial layer 119A by anisotropic etching.

[0207] By using the wet etching method, compared to the dry etching method, damage to the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B during processing of the sacrificial layer can be reduced. When using the wet etching method, it is preferable to use chemical solutions such as a developer, an aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0208] Furthermore, when using the dry etching method, the degradation of the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B can be suppressed by not using an oxygen-containing gas as the etching gas. When using the dry etching method, it is preferable to use a gas containing noble gases (also called rare gases) such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He as the etching gas.

[0209] By creating a layered structure for the sacrificial layer, a portion of the layer can be processed using the resist mask 190, and after removing the resist mask 190, the portion of the layer can be used as a hard mask to process the remaining layer.

[0210] For example, after processing the second sacrificial layer 119A using a resist mask 190, the resist mask 190 is removed by ashing using oxygen plasma or the like. At this time, the first sacrificial layer 118A is located on the outermost surface, and the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B are not exposed. Therefore, damage to the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B can be suppressed during the resist mask 190 removal process. Then, the first sacrificial layer 118A can be processed using the second sacrificial layer 119 as a hard mask, and the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B can be processed using the first sacrificial layer 118 and the second sacrificial layer 119 as a hard mask.

[0211] The processing of the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B is preferably carried out by anisotropic etching. In particular, anisotropic dry etching is preferred. As the etching gas, it is preferable to use a gas containing nitrogen, a gas containing hydrogen, a gas containing noble gas, a gas containing nitrogen and argon, or a gas containing nitrogen and hydrogen. By not using an oxygen-containing gas as the etching gas, the degradation of the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, the second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B can be suppressed.

[0212] In this case, the etching process may remove a portion of the insulator 121 that does not overlap with the resist mask 190 on its upper surface. In this case, as shown in Figure 7A, a first recess is formed on the upper surface of the insulator 121. This first recess is formed in a region that does not overlap with the first layer 113.

[0213] Next, as shown in Figure 11C, an insulating film 124A is formed covering the first layer 113, the first sacrificial layer 118, and the second sacrificial layer 119. Furthermore, an insulating film 124B is formed on top of the insulating film 124A. The insulating films 124A and 124B can be made of materials that can be used as insulators 124a and 124, respectively.

[0214] Methods for depositing insulating film 124A and insulating film 124B include vacuum deposition, sputtering, CVD, and ALD. Insulating film 124A is preferably deposited using a method that minimizes damage to the first layer 113. Furthermore, insulating film 124A and insulating film 124B are formed at a temperature lower than the heat resistance temperature of the first layer 113. For example, an aluminum oxide film can be formed as insulating film 124A using the ALD method. The ALD method is preferred because it allows for the formation of a film with high coverage. Alternatively, for example, a silicon oxide nitride film or silicon nitride film can be formed as insulating film 124B using the PECVD method or sputtering method.

[0215] Next, as shown in Figure 12A, the insulating film 124B is etched to form the insulator 124b. The insulating film 124B is preferably processed by anisotropic etching. In particular, anisotropic dry etching is preferred. For example, gases containing noble gases such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He can be used as the etching gas.

[0216] Next, as shown in Figure 12B, the insulating film 124A is etched using the insulator 124b as a hard mask to form the insulator 124a. It is preferable to process the insulating film 124A using a wet etching method. By using a wet etching method, damage to the second sacrificial layer 119 and the like during the processing of the insulator 124a can be reduced compared to when a dry etching method is used. When using a wet etching method, it is preferable to use a chemical solution containing, for example, a developer, an aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0217] In this way, an insulator 124 can be formed by laminating an insulator 124b on an insulator 124a. The side surface of the insulator 124 is in contact with the first layer 113, and the bottom surface is in contact with an insulator 121. This prevents the light-emitting device 130 from short-circuiting due to contact between the side surface of the pixel electrode 111 or the side surface of the first layer 113 and the second layer 114 or common electrode 115 that will be formed later. Furthermore, damage to the first layer 113 in later processes can be suppressed.

[0218] In this case, the etching process may remove a portion of the upper part of the insulator 121 that does not overlap with the insulator 124. In this case, as shown in Figure 7A, a second recess is formed on the upper part of the insulator 121. The second recess is formed in the region of the first recess that does not overlap with the insulator 124.

[0219] Next, as shown in Figure 12C, the second sacrificial layer 119 is removed. Furthermore, as shown in Figure 13A, the first sacrificial layer 118 is removed. As a result, the second electron transport layer 184b is exposed on the pixel electrode 111, and the conductive layer 123 is exposed at the connection portion 140.

[0220] The same method as the sacrificial layer processing method can be used for the sacrificial layer removal process. In particular, by using a wet etching method, the damage inflicted on the first layer 113, the conductive layer 123, and the insulator 124 when removing the sacrificial layer can be reduced compared to when using a dry etching method.

[0221] Next, as shown in Figure 13B, a second layer 114 is formed so as to cover the first layer 113, the conductive layer 123, the insulator 124, and the insulator 121, and a common electrode 115 is formed on the second layer 114, the insulator 121, and the conductive layer 123.

[0222] The materials that can be used as the second layer 114 are as described above. The layers constituting the second layer 114 can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating. The layers constituting the second layer 114 may also be formed using a premixed material. The second layer 114 may be omitted if it is not needed.

[0223] The materials that can be used as the common electrode 115 are as described above. For the formation of the common electrode 115, for example, sputtering or vacuum deposition can be used.

[0224] Then, as shown in Figure 13B, a protective layer 131 is formed on the common electrode 115.

[0225] The materials that can be used for the protective layer 131 are as described above. Methods for forming the protective layer 131 include vacuum deposition, sputtering, CVD, and ALD. The protective layer 131 may be a single-layer structure or a multilayer structure. For example, the protective layer 131 may be a two-layer structure formed using different deposition methods.

[0226] Next, colored layers 125a, 125b, and 125c are formed on the protective layer 131, such that they overlap with the pixel electrodes 111a, 111b, and 111c. The colored layers 125a, 125b, and 125c can be formed at desired positions using methods such as inkjet etching or photolithography. Specifically, different colored layers 125 (colored layer 125a, colored layer 125b, or colored layer 125c) can be formed for each pixel.

[0227] Then, by bonding the substrate 120 onto the protective layer 131 using a resin layer 122, the display device 100 shown in Figure 1B can be manufactured.

[0228] As described above, in the manufacturing method of the display device of this embodiment, the island-shaped EL layer is not formed by the pattern of the metal mask, but rather by processing after the EL layer has been deposited on one surface, so that the island-shaped EL layer can be formed with a uniform thickness. Furthermore, it is possible to realize a high-definition display device or a display device with a high aperture ratio, which has been difficult to achieve until now.

[0229] A display device according to one aspect of the present invention has a tandem-structured light-emitting device. The sides of the pixel electrodes, light-emitting layer, carrier transport layer, carrier injection layer, and intermediate layer of the light-emitting device are covered with sidewall-shaped insulators and ridge-shaped insulators. This configuration suppresses contact between the common electrode and the sides of the pixel electrodes, light-emitting layer, carrier transport layer, carrier injection layer, and intermediate layer, thereby suppressing short circuits in the light-emitting device.

[0230] This embodiment can be combined with other embodiments as appropriate. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, these configuration examples can be combined as appropriate.

[0231] (Embodiment 2) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figures 14 to 16.

[0232] The display device of this embodiment can be a high-resolution display device or a large-screen display device. Therefore, the display device of this embodiment can be used in electronic devices with relatively large screens, such as television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal information terminals, and audio playback devices.

[0233] [Display device 100A] Figure 14 shows a perspective view of the display device 100A, and Figure 15A shows a cross-sectional view of the display device 100A.

[0234] The display device 100A has a configuration in which substrate 152 and substrate 151 are bonded together. In Figure 14, substrate 152 is clearly indicated by a dashed line.

[0235] The display device 100A includes a display unit 162, a circuit 164, wiring 165, etc. Figure 14 shows an example in which IC 173 and FPC 172 are mounted on the display device 100A. Therefore, the configuration shown in Figure 14 can also be described as a display module having the display device 100A, an IC (integrated circuit), and an FPC.

[0236] For example, a scan line drive circuit can be used as circuit 164.

[0237] Wiring 165 has the function of supplying signals and power to the display unit 162 and the circuit 164. These signals and power are input to wiring 165 from an external source via FPC 172 or from IC 173.

[0238] Figure 14 shows an example in which IC 173 is mounted on the substrate 151 using a COG (Chip On Glass) method or COF (Chip On Film) method. IC 173 can be an IC having, for example, a scan line drive circuit or a signal line drive circuit. Note that the display device 100A and the display module may be configured without an IC. Alternatively, the IC may be mounted on an FPC using a COF method or the like.

[0239] Figure 15A shows an example of a cross-section obtained by cutting a portion of the display device 100A, including the FPC 172, a portion of the circuit 164, a portion of the display unit 162, and a portion of the area including the end.

[0240] The display device 100A shown in Figure 15A has transistors 201 and 205, light-emitting devices 130a and 130b, a colored layer 125a and 125b, etc., between substrates 151 and 152. Light-emitting devices 130a and 130b emit white light. Colored layers 125a and 125b have the function of transmitting light of different colors to each other. Although two types of colored layers are shown in Figure 15A, the display device 100A can have even more types of colored layers.

[0241] Here, if the pixels of the display device have three types of subpixels, each having a colored layer 125 that transmits light of different colors, examples of these three subpixels include subpixels of three colors: R, G, and B; and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). If there are four such subpixels, examples of these four subpixels include subpixels of four colors: R, G, B, and white (W); and subpixels of four colors: R, G, B, and Y.

[0242] The protective layer 131 and the substrate 152 are bonded together via an adhesive layer 142. For sealing the light-emitting device, a solid sealing structure or a hollow sealing structure can be applied. In Figure 15A, the space between the substrate 152 and the substrate 151 is filled with the adhesive layer 142, demonstrating a solid sealing structure. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), demonstrating a hollow sealing structure. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting device. Furthermore, the space may be filled with a resin different from the frame-shaped adhesive layer 142.

[0243] The light-emitting device 130a has a laminated structure similar to the light-emitting device 130a shown in Figure 1B, and the light-emitting device 130b has a laminated structure similar to the light-emitting device 130b shown in Figure 1B. Details of the light-emitting devices can be found in Embodiment 1. An insulator 124 is formed in contact with the side surfaces of the light-emitting device 130a and the light-emitting device 130b. A protective layer 131 is formed covering the light-emitting devices 130a, 130b, the insulator 124, and the insulator 121.

[0244] The pixel electrode 111a is connected to the conductive layer 222b of the transistor 205 through an opening in the insulating layer 214. Similarly, the pixel electrode 111b is electrically connected to one of the source and drain electrodes of the transistor 205 through an opening in the insulating layer 214.

[0245] The region including the ends of the pixel electrodes 111a and 111b is covered by an insulator 121. The pixel electrodes 111a and 111b contain a material that reflects visible light, while the common electrode 115 contains a material that transmits visible light.

[0246] The light emitted by the light-emitting device is projected onto the substrate 152. Therefore, it is preferable to use a material with high transparency to visible light for the substrate 152.

[0247] The laminated structure from the substrate 151 to the insulating layer 214 corresponds to the layer 101 containing the transistor in Embodiment 1.

[0248] Transistors 201 and 205 are both formed on the substrate 151. These transistors can be manufactured using the same materials and the same process.

[0249] On the substrate 151, insulating layers 211, 213, 215, and 214 are provided in this order. A portion of insulating layer 211 functions as a gate insulating layer for each transistor. A portion of insulating layer 213 functions as a gate insulating layer for each transistor. Insulating layer 215 is provided covering the transistors. Insulating layer 214 is provided covering the transistors and functions as a planarization layer. The number of gate insulating layers and insulating layers covering the transistors are not limited and may be a single layer or two or more layers, respectively.

[0250] It is preferable to use a material that does not easily allow impurities such as water and hydrogen to diffuse into at least one layer of the insulating layer covering the transistor. This allows the insulating layer to function as a barrier insulating film. With such a configuration, the diffusion of impurities from the outside into the transistor can be effectively suppressed, thereby improving the reliability of the display device.

[0251] It is preferable to use inorganic insulating films for insulating layer 211, insulating layer 213, and insulating layer 215. Examples of inorganic insulating films that can be used include silicon nitride film, silicon oxide nitride film, silicon oxide film, silicon nitride oxide film, aluminum oxide film, and aluminum nitride film. Alternatively, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, and neodymium oxide film may also be used. Furthermore, two or more of the above insulating films may be laminated together.

[0252] An organic insulating film is preferred for the insulating layer 214, which functions as a planarizing layer. Examples of materials that can be used as the organic insulating film include acrylic resins, polyimide resins, epoxy resins, polyamide resins, polyimidoamide resins, siloxane resins, benzocyclobutene resins, phenolic resins, and precursors of these resins.

[0253] Here, organic insulating films often have lower barrier properties than inorganic insulating films. Therefore, it is preferable that the organic insulating film has an opening near the edge of the display device 100A. This prevents impurities from entering through the organic insulating film from the edge of the display device 100A. Alternatively, the organic insulating film may be formed so that its edge is inward from the edge of the display device 100A, so that the organic insulating film is not exposed at the edge of the display device 100A.

[0254] In the region 228 shown in Figure 15A, an opening is formed in the insulating layer 214. This prevents impurities from entering the display unit 162 from the outside through the insulating layer 214, even when an organic insulating film is used for the insulating layer 214. Therefore, the reliability of the display device 100A can be improved.

[0255] Transistors 201 and 205 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as source and drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0256] The transistor structure of the display device of this embodiment is not particularly limited. For example, planar transistors, staggered transistors, inverse staggered transistors, etc., can be used. Furthermore, either a top-gate or bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below the semiconductor layer in which the channel is formed.

[0257] Transistors 201 and 205 are configured in which a semiconductor layer on which a channel is formed is sandwiched between two gates. The transistors may be driven by connecting the two gates and supplying them with the same signal. Alternatively, the threshold voltage of the transistors may be controlled by applying a potential to control the threshold voltage to one of the two gates and a potential to drive the other gate.

[0258] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors with crystalline regions in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0259] The semiconductor layer of the transistor preferably has a metal oxide (also called an oxide semiconductor). In other words, the display device of this embodiment preferably uses a transistor (hereinafter referred to as an OS transistor) that uses a metal oxide in the channel formation region. Alternatively, the semiconductor layer of the transistor may have silicon. Examples of silicon include amorphous silicon and crystalline silicon (low-temperature polysilicon, single-crystal silicon, etc.).

[0260] The semiconductor layer preferably comprises, for example, indium, M (where M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin.

[0261] In particular, it is preferable to use an oxide (also written as IGZO) containing indium (In), gallium (Ga), and zinc (Zn) as the semiconductor layer.

[0262] When the semiconductor layer is an In-M-Zn oxide, it is preferable that the atomic ratio of In in the In-M-Zn oxide is equal to or greater than the atomic ratio of M. Examples of such In-M-Zn oxide atomic ratios of metal elements include compositions where In:M:Zn=1:1:1 or close to it, In:M:Zn=1:1:1.2 or close to it, In:M:Zn=2:1:3 or close to it, In:M:Zn=3:1:2 or close to it, In:M:Zn=4:2:3 or close to it, In:M:Zn=4:2:4.1 or close to it, In:M:Zn=5:1:3 or close to it, In:M:Zn=5:1:6 or close to it, In:M:Zn=5:1:7 or close to it, In:M:Zn=5:1:8 or close to it, In:M:Zn=6:1:6 or close to it, In:M:Zn=5:2:5 or close to it, and so on. Note that "close to it" compositions include a range of ±30% of the desired atomic ratio.

[0263] For example, when the atomic ratio is described as In:Ga:Zn = 4:2:3 or a composition in the vicinity thereof, when the atomic ratio of In is 4, it includes cases where the atomic ratio of Ga is 1 or more and 3 or less, and the atomic ratio of Zn is 2 or more and 4 or less. Further, when the atomic ratio is described as In:Ga:Zn = 5:1:6 or a composition in the vicinity thereof, when the atomic ratio of In is 5, it includes cases where the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is 5 or more and 7 or less. Further, when the atomic ratio is described as In:Ga:Zn = 1:1:1 or a composition in the vicinity thereof, when the atomic ratio of In is 1, it includes cases where the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is greater than 0.1 and 2 or less.

[0264] The transistors included in the circuit 164 and the transistors included in the display unit 162 may have the same structure or different structures. The structures of the plurality of transistors included in the circuit 164 may all be the same or there may be two or more types. Similarly, the structures of the plurality of transistors included in the display unit 162 may all be the same or there may be two or more types.

[0265] FIGS. 15B and 15C show other configuration examples of the transistor.

[0266] The transistor 209 and the transistor 210 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer 231 having a channel formation region 231i and a pair of low resistance regions 231n, a conductive layer 222a connected to one of the pair of low resistance regions 231n, a conductive layer 222b connected to the other of the pair of low resistance regions 231n, an insulating layer 225 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 that covers 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. Further, an insulating layer 218 that covers the transistor may be provided.

[0267] In the transistor 209 shown in FIG. 15B, an example is shown in which the insulating layer 225 covers the upper surface and the side surfaces of the semiconductor layer 231. The conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n through openings provided in the insulating layer 225 and the insulating layer 215. One of the conductive layer 222a and the conductive layer 222b functions as a source, and the other functions as a drain.

[0268] On the other hand, in the transistor 210 shown in FIG. 15C, the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231 and does not overlap with the low-resistance region 231n. For example, by processing the insulating layer 225 using the conductive layer 223 as a mask, the structure shown in FIG. 15C can be fabricated. In FIG. 15C, the insulating layer 215 is provided covering the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n through the opening of the insulating layer 215.

[0269] A connection portion 204 is provided in a region of the substrate 151 where the substrate 152 does not overlap. In the connection portion 204, the wiring 165 is electrically connected to the FPC 172 through the conductive layer 166 and the connection layer 242. The conductive layer 166 is a conductive film obtained by processing the same conductive film as the pixel electrode. On the upper surface of the connection portion 204, the conductive layer 166 is exposed. Thereby, the connection portion 204 and the FPC 172 can be electrically connected through the connection layer 242.

[0270] It is preferable to provide a light-shielding layer 148 on the surface of the substrate 152 on the side of the substrate 151. Also, coloring layers 125a and 125b may be provided on the surface of the substrate 152 on the side of the substrate 151. In FIG. 15A, when viewed with the substrate 152 as a reference, the coloring layers 125a and 125b are provided so as to cover a part of the light-shielding layer 148.

[0271] Furthermore, various optical components can be placed on the outside of the substrate 152. Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (such as diffusion films), anti-reflective layers, and light-gathering films. Additionally, an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, and an impact-absorbing layer may be placed on the outside of the substrate 152.

[0272] By providing a protective layer 131 that covers the light-emitting device, it is possible to suppress the ingress of impurities such as water into the light-emitting device and improve the reliability of the light-emitting device.

[0273] In the region 228 near the edge of the display device 100A, it is preferable that the insulating layer 215 and the protective layer 131 are in contact with each other through an opening in the insulating layer 214. In particular, it is preferable that the inorganic insulating films are in contact with each other. This makes it possible to suppress the entry of impurities into the display unit 162 from the outside through the organic insulating film. Therefore, the reliability of the display device 100A can be improved.

[0274] Substrates 151 and 152 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, etc., respectively. The substrate on the side that extracts light from the light-emitting device should be made of a material that transmits the light. If flexible materials are used for substrates 151 and 152, the flexibility of the display device can be increased, and a flexible display can be realized. Alternatively, a polarizing plate may be used as substrate 151 or substrate 152.

[0275] As substrates 151 and 152, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. may be used. Glass of a thickness sufficient to provide flexibility may be used for one or both of substrates 151 and 152.

[0276] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy for the substrate of the display device. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence).

[0277] For substrates with high optical isotropy, the absolute value of the retardation (phase difference) is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0278] Examples of films with high optical isotropy include triacetylcellulose (TAC, also known as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0279] Furthermore, when using a film as the substrate, the film may absorb water, potentially causing wrinkles or other shape changes in the display panel. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferable to use a film with a water absorption rate of 0.1% or less, and even more preferable to use a film with a water absorption rate of 0.01% or less.

[0280] As the adhesive layer 142, various types of curing adhesives can be used, such as UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0281] As the connecting layer 242, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), etc., can be used.

[0282] Materials that can be used for conductive layers such as the gate, source, and drain of transistors, as well as various wirings and electrodes that constitute display devices, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys mainly composed of these metals. Films containing these materials can be used as single layers or in a multilayer structure.

[0283] Furthermore, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene can be used as the light-transmitting conductive material. Alternatively, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metallic materials, can be used. Alternatively, nitrides of such metallic materials (e.g., titanium nitride) may be used. When using metallic materials or alloy materials (or their nitrides), it is preferable to make them thin enough to be light-transmitting. In addition, a laminated film of the above materials can be used as a conductive layer. For example, using a laminated film of a silver-magnesium alloy and indium tin oxide is preferable because it can enhance conductivity. These can also be used as conductive layers for various wirings and electrodes that constitute a display device, and as conductive layers (conductive layers that function as pixel electrodes or common electrodes) in light-emitting devices.

[0284] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide, and aluminum oxide.

[0285] Figure 15A shows an example of a top-emission type display device 100A in which light is emitted towards the substrate 152, but the present invention is not limited to this. For example, a bottom-emission type display device in which light is emitted towards the substrate 151 may be used, as shown in Figure 16, display device 100B.

[0286] Display device 100B differs from display device 100A in that the colored layers 125a and 125b are provided between the insulating layer 213 and the insulating layer 214. The colored layers 125a and 125b are provided so as to overlap with the light-emitting devices 130a and 130b, respectively.

[0287] Further, the display device 100B is different from the display device 100A in that the pixel electrodes 111a and 111b contain a material that transmits visible light, and the common electrode 115 contains a material that reflects visible light. Here, the conductive layer 166, which is obtained by processing the same conductive film as the pixel electrodes 111a and 111b, also contains a material that transmits visible light.

[0288] Further, in the display device 100B, a material with high transmittance to visible light is used for the substrate 151.

[0289] With the above configuration, the light emitted from the light-emitting layers of the light-emitting devices 130a and 130b passes through the pixel electrodes 111a and 111b and the coloring layers 125a and 125b, respectively, and is emitted from the substrate 151 side.

[0290] This embodiment can be implemented by appropriately combining at least a part of it with other embodiments described in this specification.

[0291] (Embodiment 3) In this embodiment, a configuration example of a display module having a display device according to an aspect of the present invention will be described.

[0292] FIG. 17A is a schematic perspective view of the display module 480. The display module 480 includes a display device 400 and an FPC 490.

[0293] The display module 480 includes a substrate 401 and a substrate 402. Further, a display unit 481 is provided on the substrate 402 side. The display unit 481 is an area for displaying an image in the display module 480 and is an area where light from each pixel provided in a pixel unit 484 described later can be visually recognized.

[0294] Figure 17B shows a schematic perspective view illustrating the configuration of the substrate 401. The substrate 401 has a configuration in which a circuit section 482, a pixel circuit section 483 on the circuit section 482, and a pixel section 484 on the pixel circuit section 483 are stacked. In addition, the substrate 401 has a terminal section 485 for connecting to the FPC 490 in a portion that does not overlap with the pixel section 484. The terminal section 485 and the circuit section 482 are electrically connected by a wiring section 486 composed of multiple wires.

[0295] The pixel section 484 has a plurality of pixels 484a arranged periodically. An enlarged view of one pixel 484a is shown on the right side of Figure 17B. Pixel 484a has sub-pixels 110a, 110b, and 110c. The configuration of sub-pixels 110a, 110b, and 110c and their surroundings can be referenced from the previous embodiment.

[0296] The pixel circuit section 483 has a plurality of periodically arranged pixel circuits 483a. The plurality of pixels 484a and the plurality of pixel circuits 483a may be arranged in a stripe arrangement as shown in Figure 17B. However, the plurality of pixels 484a and the plurality of pixel circuits 483a may not be limited to a stripe arrangement, but may also be arranged in a delta arrangement or the like.

[0297] A single pixel circuit 483a is a circuit that controls the light emission of the three light-emitting elements of a single pixel 484a. A single pixel circuit 483a may be configured to have three circuits that control the light emission of a single light-emitting element. For example, a single pixel circuit 483a may have at least one selection transistor, one current control transistor (drive transistor), and a capacitive element for each light-emitting element. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain. This realizes an active-matrix type display device.

[0298] The circuit section 482 has circuits for driving each pixel circuit 483a of the pixel circuit section 483. For example, it is preferable to have a gate line drive circuit, a source line drive circuit, etc. In addition, it may also have an arithmetic circuit, a memory circuit, a power supply circuit, etc.

[0299] The FPC490 functions as wiring for supplying video signals or power supply potential, etc., to the circuit section 482 from an external source. An IC may also be mounted on the FPC490.

[0300] The display module 480 can be configured such that a pixel circuit section 483 or a circuit section 482 is stacked on the lower side of the pixel section 484, thereby enabling an extremely high aperture ratio (effective display area ratio) of the display section 481. For example, the aperture ratio of the display section 481 can be 40% or more and less than 100%, preferably 50% or more and 95%, and more preferably 60% or more and 95%. Furthermore, it is possible to arrange the pixels 484a at an extremely high density, enabling an extremely high resolution of the display section 481. For example, it is preferable that the pixels 484a are arranged in the display section 481 with a resolution of 20000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and with a resolution of 20000 ppi or less, or 30000 ppi or less.

[0301] Because of its extremely high resolution, the display module 480 is suitable for use in VR devices such as head-mounted displays, or in glasses-type AR devices. For example, even in a configuration where the display unit of the display module 480 is viewed through lenses, the display module 480 has an extremely high-resolution display unit 481, so even when the display unit is magnified with lenses, pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 480 is not limited to this and can be suitably used in electronic devices with relatively small display units. For example, it can be suitably used in the display unit of wearable electronic devices such as wristwatches.

[0302] The following describes the structure of each display device (display device 400A to display device 400C) that can be used with the above-mentioned display device 400.

[0303] [Configuration Example 1] Figure 18A is a schematic cross-sectional view of the display device 400A.

[0304] The display device 400A includes a substrate 401, sub-pixels 110a, 110b, 110c, a capacitive element 440, a transistor 410, and the like.

[0305] The stacked structure from the substrate 401 to the capacitive element 440 corresponds to the layer 101 containing the transistor in Embodiment 1.

[0306] The transistor 410 is a transistor in which a channel formation region is formed on a substrate 401. As the substrate 401, a semiconductor substrate such as a single-crystal silicon substrate can be used. The transistor 410 has a part of the substrate 401, a conductive layer 411, a low-resistance region 412, an insulating layer 413, an insulating layer 414, etc. The conductive layer 411 functions as a gate electrode. The insulating layer 413 is located between the substrate 401 and the conductive layer 411 and functions as a gate insulating layer. The low-resistance region 412 is a region of the substrate 401 doped with impurities and functions as either a source or a drain. The insulating layer 414 is provided covering the side surface of the conductive layer 411.

[0307] Furthermore, an element isolation layer 415 is provided between two adjacent transistors 410 so as to be embedded in the substrate 401.

[0308] Furthermore, an insulating layer 461 is provided covering the transistor 410, and a capacitive element 440 is provided on the insulating layer 461.

[0309] The capacitive element 440 has a conductive layer 441, a conductive layer 442, and an insulating layer 443 located between them. The conductive layer 441 functions as one electrode of the capacitive element 440, the conductive layer 442 functions as the other electrode of the capacitive element 440, and the insulating layer 443 functions as the dielectric of the capacitive element 440.

[0310] The conductive layer 441 is provided on the insulating layer 461 and is electrically connected to either the source or drain of the transistor 410 by a plug 471 embedded in the insulating layer 461. The insulating layer 443 is provided covering the conductive layer 441. The conductive layer 442 is provided in the region that overlaps with the conductive layer 441 via the insulating layer 443.

[0311] An insulating layer 321 is provided covering the capacitive element 440, and sub-pixels 110a, 110b, 110c, etc. are provided on the insulating layer 321. The pixel electrodes of sub-pixels 110a, 110b, and 110c are electrically connected to the conductive layer 441 by plugs 331 embedded in the insulating layer 321 and insulating layer 443. Here, an example using the configuration exemplified in Figure 1B is shown for the sub-pixels 110a, 110b, 110c, etc., but it is not limited to this, and various configurations exemplified above can be applied.

[0312] In the display device 400A, a protective layer 131, an insulating layer 362, and an insulating layer 363 are provided in this order to cover the common electrode 115 of the light-emitting elements of the sub-pixels 110a, 110b, and 110c. These three insulating layers function as protective layers to prevent impurities such as water from diffusing into the light-emitting elements of the sub-pixels 110a, 110b, and 110c. It is preferable to use an inorganic insulating film with low moisture permeability, such as a silicon oxide film, a silicon nitride film, or an aluminum oxide film, for the insulating layer 363. In addition, an organic insulating film with high light permeability can be used for the insulating layer 362. By using an organic insulating film for the insulating layer 362, the influence of the uneven shape below the insulating layer 362 can be mitigated, and the surface on which the insulating layer 363 is formed can be made smooth. As a result, defects such as pinholes are less likely to occur in the insulating layer 363, and the moisture permeability of the protective layer can be further improved. The protective layer covering the light-emitting elements of sub-pixels 110a, 110b, and 110c is not limited to this configuration; it may be a single layer, a two-layer structure, or a stacked structure of four or more layers.

[0313] The display device 400A has a substrate 402 on the viewing side. Substrate 402 and substrate 401 are bonded together by a light-transmitting adhesive layer 364. As substrate 402, a light-transmitting substrate such as a glass substrate, quartz substrate, sapphire substrate, or plastic substrate can be used.

[0314] This configuration makes it possible to realize a display device with extremely high resolution and high display quality.

[0315] [Configuration Example 2] Figure 19 is a schematic cross-sectional view of the display device 400B. The display device 400B differs from the display device 400A mainly in its transistor configuration.

[0316] Transistor 420 is a transistor in which a metal oxide (also called an oxide semiconductor) is applied to the semiconductor layer where the channel is formed.

[0317] The transistor 420 has a semiconductor layer 421, an insulating layer 423, a conductive layer 424, a pair of conductive layers 425, an insulating layer 426, a conductive layer 427, and so on.

[0318] As the substrate 401 on which the transistor 420 is provided, the insulating substrate or semiconductor substrate described above can be used.

[0319] An insulating layer 432 is provided on the substrate 401. The insulating layer 432 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 401 to the transistor 420, and prevents oxygen from detaching from the semiconductor layer 421 to the insulating layer 432. As the insulating layer 432, for example, a film that is less susceptible to hydrogen or oxygen diffusion than a silicon oxide film can be used, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0320] A conductive layer 427 is provided on an insulating layer 432, and an insulating layer 426 is provided covering the conductive layer 427. The conductive layer 427 functions as the first gate electrode of the transistor 420, and a portion of the insulating layer 426 functions as the first gate insulating layer. It is preferable to use an oxide insulating film, such as a silicon oxide film, for at least the portion of the insulating layer 426 that is in contact with the semiconductor layer 421. It is preferable that the upper surface of the insulating layer 426 is flattened.

[0321] The semiconductor layer 421 is provided on the insulating layer 426. Preferably, the semiconductor layer 421 has a metal oxide (also called an oxide semiconductor) film having semiconductor properties. Details of materials suitable for use in the semiconductor layer 421 will be described later.

[0322] A pair of conductive layers 425 are provided in contact with the semiconductor layer 421 and function as source and drain electrodes.

[0323] Furthermore, an insulating layer 428 is provided covering the top and side surfaces of the pair of conductive layers 425, as well as the side surfaces of the semiconductor layer 421, and an insulating layer 461b is provided on the insulating layer 428. The insulating layer 428 functions as a barrier insulating film that prevents impurities such as water or hydrogen from diffusing into the semiconductor layer 421 from the insulating layer 461b, etc., and prevents oxygen from detaching from the semiconductor layer 421. As the insulating layer 428, an insulating film similar to that of the insulating layer 432 can be used.

[0324] An opening is provided in the insulating layer 428 and the insulating layer 461b that reaches the semiconductor layer 421. Inside this opening, an insulating layer 423 and a conductive layer 424 are embedded, which are in contact with the sides of the insulating layer 461b, the insulating layer 428, and the conductive layer 425, as well as the upper surface of the semiconductor layer 421. The conductive layer 424 functions as a second gate electrode, and the insulating layer 423 functions as a second gate insulating layer.

[0325] The upper surfaces of the conductive layer 424, the insulating layer 423, and the insulating layer 461b are flattened so that their heights are approximately the same, and the insulating layer 429 and insulating layer 461a are provided covering them.

[0326] Insulating layers 461a and 461b function as interlayer insulating layers. In addition, insulating layer 429 functions as a barrier insulating film that prevents impurities such as water or hydrogen from diffusing from insulating layer 461a, etc., to the transistor 420. As insulating layer 429, an insulating film similar to that used for insulating layers 428 and 432 can be used.

[0327] A plug 471, which is electrically connected to one of the pair of conductive layers 425, is provided so as to be embedded in the insulating layer 461a, insulating layer 429, and insulating layer 461b. Here, it is preferable that the plug 471 has a conductive layer 471a that covers the sides of the openings of each of the insulating layer 461a, insulating layer 461b, insulating layer 429, and insulating layer 428, and a part of the upper surface of the conductive layer 425, and a conductive layer 471b that is in contact with the upper surface of the conductive layer 471a. In this case, it is preferable to use a conductive material that does not easily allow hydrogen and oxygen to diffuse as the conductive layer 471a.

[0328] [Configuration Example 3] Figure 20 is a schematic cross-sectional view of the display device 400C. The display device 400C has a configuration in which a transistor 410 in which a channel is formed and a transistor 420 containing a metal oxide are stacked on a substrate 401.

[0329] An insulating layer 461 is provided covering the transistor 410, and a conductive layer 451 is provided on the insulating layer 461. An insulating layer 462 is provided covering the conductive layer 451, and a conductive layer 452 is provided on the insulating layer 462. The conductive layers 451 and 452 each function as wiring. An insulating layer 463 and an insulating layer 432 are provided covering the conductive layer 452, and a transistor 420 is provided on the insulating layer 432. An insulating layer 465 is provided covering the transistor 420, and a capacitive element 440 is provided on the insulating layer 465. The capacitive element 440 and the transistor 420 are electrically connected by a plug 474.

[0330] Transistor 420 can be used as a transistor constituting a pixel circuit. Transistor 410 can also be used as a transistor constituting a pixel circuit, or as a transistor constituting a drive circuit (gate line drive circuit, source line drive circuit) for driving the pixel circuit. Furthermore, transistors 410 and 420 can be used as transistors constituting various circuits such as arithmetic circuits or memory circuits.

[0331] This configuration allows for the formation of not only pixel circuits but also drive circuits and other components directly beneath the light-emitting unit, making it possible to miniaturize the display device compared to cases where the drive circuits are located around the display area.

[0332] The following describes the components, such as transistors, that can be applied to display devices.

[0333] [Transistor] A transistor comprises a conductive layer that functions as a gate electrode, a semiconductor layer, a conductive layer that functions as a source electrode, a conductive layer that functions as a drain electrode, and an insulating layer that functions as a gate insulating layer.

[0334] The structure of the transistor in the display device according to one aspect of the present invention is not particularly limited. For example, it may be a planar transistor, a staggered transistor, or an inverse staggered transistor. It may also be a top-gate or bottom-gate transistor structure. Alternatively, gate electrodes may be provided above and below the channel.

[0335] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors with crystalline regions in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0336] The following section will describe transistors that use metal oxide films as the semiconductor layer in which the channel is formed (OS transistors).

[0337] As semiconductor materials used in transistors, metal oxides with an energy gap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more, can be used. Typical examples include metal oxides containing indium, such as CAC-OS described later.

[0338] Transistors made from metal oxides, which have a wider bandgap and lower carrier density than silicon, can retain the charge stored in a capacitive element connected in series with the transistor for a long period of time due to their low off-current.

[0339] The semiconductor layer can be a film represented as an In-M-Zn oxide containing, for example, indium, zinc, and M (where M is a metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium).

[0340] When the metal oxide constituting the semiconductor layer is an In-M-Zn system oxide, it is preferable that the atomic ratio of the metal elements in the sputtering target used to deposit the In-M-Zn oxide satisfy In≧M and Zn≧M. Preferred atomic ratios of the metal elements in such a sputtering target include In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=3:1:2, In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:6, In:M:Zn=5:1:7, and In:M:Zn=5:1:8. The atomic ratio of the deposited semiconductor layer includes a variation of plus or minus 40% of the atomic ratio of the metal elements contained in the sputtering target.

[0341] [Conductive layer] Materials that can be used for conductive layers such as the gate, source, and drain of transistors, as well as various wirings and electrodes that constitute display devices, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or alloys mainly composed of these metals. Films containing these materials can be used as single layers or in multilayer structures. For example, there are single-layer structures of aluminum films containing silicon, two-layer structures of aluminum films laminated on titanium films, two-layer structures of aluminum films laminated on tungsten films, two-layer structures of copper films laminated on copper-magnesium-aluminum alloy films, two-layer structures of copper films laminated on titanium films, two-layer structures of copper films laminated on tungsten films, three-layer structures of titanium films or titanium nitride films with aluminum films or copper films laminated on top and titanium films or titanium nitride films formed on top of those, and three-layer structures of molybdenum films or molybdenum nitride films with aluminum films or copper films laminated on top and molybdenum films or molybdenum nitride films formed on top of those. Furthermore, oxides such as indium oxide, tin oxide, or zinc oxide may be used. In addition, using copper containing manganese is preferable because it improves the controllability of the shape through etching.

[0342] [Insulating layer] In addition to resins such as acrylic resin and epoxy resin, and resins having siloxane bonds such as silicone, inorganic insulating materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon nitride, and aluminum oxide can also be used as insulating materials for each insulating layer.

[0343] Furthermore, it is preferable that the light-emitting element is placed between a pair of low-permeability insulating films (barrier insulating films). This prevents impurities such as water from entering the light-emitting element, thereby suppressing a decrease in the reliability of the device.

[0344] Examples of the low-permeability insulating film include films containing nitrogen and silicon such as silicon nitride films and silicon oxynitride films, or films containing nitrogen and aluminum such as aluminum nitride films. Further, silicon oxide films, silicon oxynitride films, aluminum oxide films, etc. may be used.

[0345] For example, the water vapor transmission rate of the low-permeability insulating film is 1 × 10 -5 [g / (m 2 ·day)] or less, preferably 1 × 10 -6 [g / (m 2 ·day)] or less, more preferably 1 × 10 -7 [g / (m 2 ·day)] or less, still more preferably 1 × 10 -8 [g / (m 2 ·day)] or less.

[0346] This embodiment can be implemented by appropriately combining at least a part thereof with other embodiments described in this specification.

[0347] (Embodiment 4) In this embodiment, a metal oxide (also referred to as an oxide semiconductor) that can be used for the OS transistor described in the above embodiment will be described.

[0348] The metal oxide preferably contains at least indium or zinc. Particularly preferably, it contains indium and zinc. In addition to these, it is preferable that aluminum, gallium, yttrium, tin, etc. are contained. Further, one or more selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, etc. may be contained.

[0349] Furthermore, metal oxides can be formed by methods such as sputtering, chemical vapor deposition (CVD) methods including metal-organic chemical vapor deposition (MOCVD), or atomic layer deposition (ALD).

[0350] <Classification of crystal structures> Examples of crystalline structures for oxide semiconductors include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and polycrystal.

[0351] The crystal structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectroscopy. For example, it can be evaluated using the XRD spectrum obtained by GIXD (Grazing-Incidence XRD) measurement. The GIXD method is also known as the thin-film method or the Seemann-Bohlin method.

[0352] For example, in a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, in an IGZO film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical shape of the XRD spectrum peak clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0353] Furthermore, the crystalline structure of a film or substrate can be evaluated by the diffraction pattern (also called the nano-beam electron diffraction pattern) observed using nano-beam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, confirming that the quartz glass is in an amorphous state. However, in the diffraction pattern of an IGZO film deposited at room temperature, a spot-like pattern is observed instead of a halo. Therefore, it is presumed that an IGZO film deposited at room temperature is in an intermediate state, neither crystalline nor amorphous, and cannot be concluded to be in an amorphous state.

[0354] <<Oxide semiconductor structure>> It should be noted that oxide semiconductors may be classified differently from those described above when considering their structure. For example, oxide semiconductors can be divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the aforementioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors also include polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0355] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0356] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, the c-axis of which is oriented in a specific direction. This specific direction is the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region with periodic atomic arrangement. If we consider the atomic arrangement as a lattice arrangement, then a crystalline region is also a region with a aligned lattice arrangement. Furthermore, CAAC-OS has regions where multiple crystalline regions are connected in the ab-plane direction, and these regions may exhibit distortion. Distortion refers to a point in the connected region where the orientation of the lattice arrangement changes between a region with a aligned lattice arrangement and another region with a aligned lattice arrangement. In short, CAAC-OS is an oxide semiconductor that is c-axis oriented and does not exhibit clear orientation in the ab-plane direction.

[0357] Each of the multiple crystalline regions described above is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of a single minute crystal, the maximum diameter of that crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of that crystalline region may be around several tens of nanometers.

[0358] Furthermore, in In-M-Zn oxides (where element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), CAAC-OS tends to have a layered crystalline structure (also called a layered structure) consisting of layers containing indium (In) and oxygen (hereinafter referred to as the In layer) and layers containing element M, zinc (Zn), and oxygen (hereinafter referred to as the (M,Zn) layer). Note that indium and element M are mutually substitutable. Therefore, the (M,Zn) layer may contain indium. Also, the In layer may contain element M. Also, the In layer may contain Zn. This layered structure can be observed, for example, as a lattice image in high-resolution TEM (Transmission Electron Microscope) images.

[0359] When structural analysis of a CAAC-OS film is performed using an XRD instrument, for example, out-of-plane XRD measurements using θ / 2θ scanning show a peak indicating c-axis orientation at 2θ = 31° or nearby. Note that the position of the c-axis orientation peak (value of 2θ) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0360] Furthermore, for example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film. These spots are observed at point-symmetric positions with respect to the incident electron beam spot (also called the direct spot) that passed through the sample.

[0361] When the crystal region is observed from the specific direction described above, the lattice arrangement within that crystal region is based on a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the strain may have lattice arrangements such as pentagons or heptagons. Moreover, in CAAC-OS, clear grain boundaries cannot be observed even near the strain. In other words, it can be seen that the formation of grain boundaries is suppressed by the strain in the lattice arrangement. This is thought to be because CAAC-OS can tolerate strain due to the fact that the arrangement of oxygen atoms is not dense in the ab-plane direction, and the bond distance between atoms changes due to the substitution of metal atoms.

[0362] A crystal structure in which clear grain boundaries are observed is called a polycrystal. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in transistor on-current and field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries are not observed, is one of the crystalline oxides with a suitable crystal structure for the semiconductor layer of a transistor. In addition, a structure containing Zn is preferred for the composition of CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are preferred because they suppress the generation of grain boundaries more than In oxide.

[0363] CAAC-OS is an oxide semiconductor with high crystallinity and no clearly defined grain boundaries. Therefore, CAAC-OS is less susceptible to the decrease in electron mobility caused by grain boundaries. Furthermore, since the crystallinity of oxide semiconductors can decrease due to the inclusion of impurities and the generation of defects, CAAC-OS can be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Consequently, oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat resistant and highly reliable. In addition, CAAC-OS is stable even at high temperatures (so-called thermal budget) during the manufacturing process. Therefore, using CAAC-OS in OS transistors allows for greater flexibility in the manufacturing process.

[0364] [nc-OS] nc-OS exhibits periodicity in atomic arrangement in minute regions (e.g., regions between 1 nm and 10 nm, particularly between 1 nm and 3 nm). In other words, nc-OS contains minute crystals. These minute crystals are also called nanocrystals because their size is, for example, between 1 nm and 10 nm, particularly between 1 nm and 3 nm. Furthermore, nc-OS shows no regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Consequently, depending on the analytical method, nc-OS may be indistinguishable from a-like OS or amorphous oxide semiconductors. For example, when structural analysis of an nc-OS film is performed using an XRD instrument, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Also, when electron diffraction (also called limited-field electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of the nanocrystals (e.g., 50 nm or larger), a diffraction pattern resembling a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystal (for example, 1 nm to 30 nm), an electron diffraction pattern may be obtained in which multiple spots are observed within a ring-shaped region centered on a direct spot.

[0365] [a-like OS] a-like OS is an oxide semiconductor having a structure between nc-OS and amorphous oxide semiconductors. a-like OS has porous or low-density regions. That is, a-like OS has lower crystallinity compared to nc-OS and CAAC-OS. Also, a-like OS has a higher hydrogen concentration in the film compared to nc-OS and CAAC-OS.

[0366] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0367] [CAC-OS] CAC-OS is a material composition in which, for example, the elements constituting the metal oxide are unevenly distributed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size. In the following, a state in which one or more metal elements are unevenly distributed in a metal oxide, and the regions containing these metal elements are mixed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size, is also referred to as a mosaic or patchy state.

[0368] Furthermore, CAC-OS is a composite metal oxide having a mosaic-like structure formed by the separation of the material into a first region and a second region, with the first region distributed within the film (hereinafter also referred to as a cloud-like structure). In other words, CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0369] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS of In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of the CAC-OS film. The second region is the region where [Ga] is greater than the [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is the region where [In] is greater than the [In] in the second region, and [Ga] is smaller than the [Ga] in the second region. The second region is the region where [Ga] is greater than the [Ga] in the first region, and [In] is smaller than the [In] in the first region.

[0370] Specifically, the first region described above is a region whose main components are indium oxide, indium zinc oxide, etc. The second region described above is a region whose main components are gallium oxide, gallium zinc oxide, etc. In other words, the first region can be rephrased as a region whose main component is In. Similarly, the second region can be rephrased as a region whose main component is Ga.

[0371] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

[0372] Furthermore, CAC-OS in In-Ga-Zn oxide refers to a material composition containing In, Ga, Zn, and O, in which regions with Ga as the main component and regions with In as the main component are arranged in a mosaic-like manner, with these regions existing randomly. Therefore, it is presumed that CAC-OS has a structure in which metal elements are unevenly distributed.

[0373] CAC-OS can be formed, for example, by sputtering under conditions where the substrate is not heated. When forming CAC-OS by sputtering, one or more gases selected from inert gases (typically argon), oxygen gas, and nitrogen gas may be used as the film-forming gas. Furthermore, it is preferable that the ratio of the oxygen gas flow rate to the total flow rate of the film-forming gas during film formation be as low as possible. For example, it is preferable that the ratio of the oxygen gas flow rate to the total flow rate of the film-forming gas during film formation be 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0374] Furthermore, for example, in the case of CAC-OS in In-Ga-Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) confirms that it has a structure in which regions mainly composed of In (first region) and regions mainly composed of Ga (second region) are unevenly distributed and mixed.

[0375] Here, the first region is a region with higher conductivity compared to the second region. In other words, the conductivity of the metal oxide is exhibited when carriers flow through the first region. Therefore, a high field-effect mobility (μ) can be achieved when the first region is distributed in a cloud-like manner within the metal oxide.

[0376] On the other hand, the second region is a region with higher insulating properties compared to the first region. In other words, the distribution of the second region within the metal oxide can suppress leakage current.

[0377] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulation due to the second region work complementaryly to give CAC-OS a switching function (on / off function). In other words, CAC-OS has conductive function in part of the material, insulating function in part of the material, and semiconductor function as a whole. By separating the conductive function and the insulating function, both functions can be maximized. Therefore, by using CAC-OS in a transistor, a high on-current (I on ), high field-effect mobility (μ), and good switching operation can be achieved.

[0378] Furthermore, transistors using CAC-OS offer high reliability. Therefore, CAC-OS is ideal for various semiconductor devices, including display devices.

[0379] Oxide semiconductors can take on diverse structures, each possessing different properties. One embodiment of the present invention may include two or more of the following: amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0380] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0381] By using the above-mentioned oxide semiconductor in transistors, it is possible to realize transistors with high field-effect mobility. Furthermore, it is possible to realize highly reliable transistors.

[0382] It is preferable to use an oxide semiconductor with a low carrier concentration for the transistor. For example, the carrier concentration of an oxide semiconductor is 1 × 10⁻⁶. 17 cm -3 The following is preferably 1 × 10 15 cm -3 More preferably 1 × 10 13 cm -3More preferably 1 × 10 11 cm -3 More preferably 1 × 10 10 cm -3 It is less than 1 × 10 -9 cm -3 This concludes the explanation. Furthermore, when lowering the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film should be lowered to reduce the defect level density. In this specification, a low impurity concentration and low defect level density are referred to as high-purity intrinsic or substantially high-purity intrinsic. Note that oxide semiconductors with low carrier concentrations are sometimes referred to as high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors.

[0383] Furthermore, oxide semiconductor films that are highly intrinsic or substantially highly intrinsic may have a low trap level density due to their low defect level density.

[0384] Furthermore, charges trapped in the trap levels of oxide semiconductors can take a long time to disappear, sometimes behaving like fixed charges. Therefore, transistors in which channel formation regions are formed in oxide semiconductors with a high trap level density may exhibit unstable electrical properties.

[0385] Therefore, reducing the impurity concentration in the oxide semiconductor is effective in stabilizing the electrical characteristics of the transistor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in adjacent films. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon.

[0386] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0387] In oxide semiconductors, the presence of silicon or carbon, which are Group 14 elements, leads to the formation of defect levels in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are compared by 2 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 17 atoms / cm 3 The following applies:

[0388] Furthermore, if an oxide semiconductor contains alkali metals or alkaline earth metals, it may form defect levels and generate carriers. Therefore, transistors using oxide semiconductors containing alkali metals or alkaline earth metals tend to exhibit normally-on characteristics. For this reason, the concentration of alkali metals or alkaline earth metals in the oxide semiconductor obtained by SIMS should be set to 1 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 16 atoms / cm 3 Do the following:

[0389] Furthermore, in oxide semiconductors, the presence of nitrogen generates electrons, which act as carriers, increasing the carrier concentration and making it easier for the semiconductor to become n-type. As a result, transistors using oxide semiconductors containing nitrogen tend to exhibit normally-on characteristics. Alternatively, the presence of nitrogen in oxide semiconductors can lead to the formation of trap levels. As a result, the electrical properties of the transistor may become unstable. For this reason, the nitrogen concentration in oxide semiconductors obtained by SIMS should be set to 5 × 10⁻⁶. 19 atoms / cm 3 Less than 5 × 10 18 atoms / cm 3 More preferably 1 × 10 18 atoms / cm 3 More preferably 5 × 10 17 atoms / cm 3 Do the following:

[0390] Furthermore, hydrogen contained in oxide semiconductors can react with oxygen bonded to metal atoms to form water, potentially creating oxygen vacancies. Hydrogen can then fill these vacancies, generating electrons, which act as carriers. Additionally, some of the hydrogen can combine with oxygen bonded to metal atoms to generate electrons. Therefore, transistors using oxide semiconductors containing hydrogen tend to exhibit normally-on characteristics. For this reason, it is preferable to reduce the hydrogen content in oxide semiconductors as much as possible. Specifically, in oxide semiconductors, the hydrogen concentration obtained by SIMS should be 1 × 10⁻⁶. 20 atoms / cm 3 Less than 1 × 10 19 atoms / cm 3 Less than 5x10 18 atoms / cm 3 Less than 1 × 10 18 atoms / cm 3 Make it less than.

[0391] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be imparted.

[0392] This embodiment can be combined with other embodiments as appropriate.

[0393] (Embodiment 5) In this embodiment, an electronic device according to one aspect of the present invention will be described with reference to Figures 21 to 23.

[0394] The electronic device of this embodiment has a display device according to one aspect of the present invention in its display unit. The display device according to one aspect of the present invention is easily made high-definition and high-resolution. Therefore, it can be used in the display units of various electronic devices.

[0395] Examples of electronic devices include television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as other electronic devices with relatively large screens, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, and audio playback devices.

[0396] In particular, a display device according to one aspect of the present invention can be used suitably in electronic devices having a relatively small display area because it can increase the resolution. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), as well as wearable devices that can be worn on the head, such as VR devices such as head-mounted displays, AR devices such as glasses, and MR devices.

[0397] A display device according to one aspect of the present invention preferably has an extremely high resolution such as HD (1280 x 720 pixels), FHD (1920 x 1080 pixels), WQHD (2560 x 1440 pixels), WQXGA (2560 x 1600 pixels), 4K (3840 x 2160 pixels), or 8K (7680 x 4320 pixels). In particular, a resolution of 4K, 8K, or higher is preferred. Furthermore, the pixel density (resolution) of the display device according to one aspect of the present invention is preferably 100 ppi or more, preferably 300 ppi or more, more preferably 500 ppi or more, more preferably 1000 ppi or more, more preferably 2000 ppi or more, more preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 7000 ppi or more. By using a display device that has either high resolution or high detail, or both, it becomes possible to further enhance the sense of presence and depth in personal electronic devices such as portable or home-use devices. Furthermore, there are no particular limitations on the screen ratio (aspect ratio) of the display device according to one embodiment of the present invention. For example, the display device can support various screen ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0398] The electronic device of this embodiment may have sensors (including those with the function of measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation).

[0399] The electronic device of this embodiment can have a variety of functions. For example, it can have a function to display various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function to display a calendar, date or time, a function to execute various software (programs), a wireless communication function, a function to read programs or data recorded on a recording medium, and so on.

[0400] The electronic device 6500 shown in Figure 21A is a portable information terminal that can be used as a smartphone.

[0401] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508, etc. The display unit 6502 has a touch panel function.

[0402] A display device according to one embodiment of the present invention can be applied to the display unit 6502.

[0403] Figure 21B is a schematic cross-sectional view of the housing 6501, including the end on the microphone 6506 side.

[0404] A light-transmitting protective member 6510 is provided on the display side of the housing 6501, and the display panel 6511, optical member 6512, touch sensor panel 6513, printed circuit board 6517, battery 6518, etc. are arranged in the space enclosed by the housing 6501 and the protective member 6510.

[0405] The protective member 6510 is fixed to the display panel 6511, the optical member 6512, and the touch sensor panel 6513 by an adhesive layer (not shown).

[0406] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and the FPC 6515 is connected to this folded portion. IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals provided on the printed circuit board 6517.

[0407] A flexible display according to one embodiment of the present invention can be applied to the display panel 6511. This makes it possible to realize an extremely lightweight electronic device. Furthermore, because the display panel 6511 is extremely thin, it is possible to incorporate a large-capacity battery 6518 while keeping the thickness of the electronic device low. In addition, by folding back a part of the display panel 6511 and placing the connection part with the FPC 6515 on the back of the pixel area, it is possible to realize an electronic device with a narrow bezel.

[0408] Figure 22A shows an example of a television system. The television system 7100 has a display unit 7000 incorporated into a housing 7101. Here, the housing 7101 is shown supported by a stand 7103.

[0409] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0410] The television device 7100 shown in Figure 22A can be operated using the operation switches on the housing 7101 and a separate remote control unit 7111. Alternatively, the display unit 7000 may be equipped with a touch sensor, and the television device 7100 can be operated by touching the display unit 7000 with a finger or the like. The remote control unit 7111 may have a display unit that displays information output from the remote control unit 7111. Channels and volume can be controlled and the image displayed on the display unit 7000 can be controlled using the operation keys or touch panel on the remote control unit 7111.

[0411] The television system 7100 is configured to include a receiver and a modem. The receiver can receive general television broadcasts. Furthermore, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0412] Figure 22B shows an example of a notebook personal computer. The notebook personal computer 7200 has a casing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, etc. A display unit 7000 is incorporated into the casing 7211.

[0413] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0414] Figures 22C and 22D show examples of digital signage.

[0415] The digital signage 7300 shown in Figure 22C comprises a housing 7301, a display unit 7000, and a speaker 7303, etc. Furthermore, it may include LED lamps, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc.

[0416] Figure 22D shows a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 has a display unit 7000 that is provided along the curved surface of the column 7401.

[0417] In Figures 22C and 22D, a display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0418] The larger the display area 7000, the more information can be provided at once. Furthermore, a larger display area 7000 is more eye-catching, which can, for example, enhance the effectiveness of advertising.

[0419] Applying a touch panel to the display unit 7000 is preferable because it not only allows images or videos to be displayed on the display unit 7000, but also enables intuitive operation by the user. Furthermore, when used for purposes such as providing route information or traffic information, intuitive operation can enhance usability.

[0420] Furthermore, as shown in Figures 22C and 22D, it is preferable that the digital signage 7300 or digital signage 7400 can be linked wirelessly with an information terminal 7311 or information terminal 7411 such as a smartphone owned by the user. For example, the advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or information terminal 7411. In addition, the display on the display unit 7000 can be switched by operating the information terminal 7311 or information terminal 7411.

[0421] Furthermore, the digital signage 7300 or digital signage 7400 can be used to run games using the screen of the information terminal 7311 or information terminal 7411 as the control device (controller). This allows an unspecified number of users to participate in and enjoy the game simultaneously.

[0422] The electronic equipment shown in Figures 23A to 23F includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), connection terminals 9006, sensors 9007 (including functions for measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation), a microphone 9008, etc.

[0423] The electronic devices shown in Figures 23A to 23F have various functions. For example, they may have functions to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date or time, a function to control processing by various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. However, the functions of electronic devices are not limited to these and can have various functions. Electronic devices may have multiple display units. Furthermore, electronic devices may be equipped with a camera, etc., and have functions to capture still images or videos and save them to a recording medium (external or built into the camera), a function to display the captured images on a display unit, etc.

[0424] The details of the electronic equipment shown in Figures 23A to 23F will be explained below.

[0425] Figure 23A is a perspective view showing a personal digital assistant (PDA) 9101. The PDA 9101 can be used, for example, as a smartphone. The PDA 9101 may also be equipped with a speaker 9003, connection terminals 9006, sensors 9007, etc. The PDA 9101 can also display text and image information on multiple surfaces. Figure 23A shows an example where three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the subject of an email or SNS message, the sender's name, date and time, time, battery level, signal strength, etc. Alternatively, icons 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0426] Figure 23B is a perspective view showing the personal digital assistant (PDA) 9102. The PDA 9102 has the function of displaying information on three or more sides of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, a user can check information 9053, which is displayed in a position that can be observed from above the PDA 9102, while the PDA 9102 is stored in the breast pocket of their clothing. The user can check the display without taking the PDA 9102 out of their pocket and decide, for example, whether or not to answer a call.

[0427] Figure 23C is a perspective view showing a wristwatch-type personal information terminal 9200. The personal information terminal 9200 can be used, for example, as a smartwatch (registered trademark). The display unit 9001 has a curved display surface, allowing it to display information along the curved surface. The personal information terminal 9200 can also make hands-free calls by communicating with, for example, a wireless communication headset. Furthermore, the personal information terminal 9200 can transmit data to other information terminals and be charged via a connection terminal 9006. Charging may be performed by wireless power supply.

[0428] Figures 23D to 23F are perspective views showing a foldable personal information terminal 9201. Figure 23D shows the personal information terminal 9201 in an unfolded state, Figure 23F shows it in a folded state, and Figure 23E shows a perspective view of the state in between, transitioning from one of Figures 23D or 23F to the other. The personal information terminal 9201 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state. The display unit 9001 of the personal information terminal 9201 is supported by three housings 9000 connected by a hinge 9055. For example, the display unit 9001 can be bent with a radius of curvature of 0.1 mm to 150 mm.

[0429] This embodiment can be combined with other embodiments as appropriate. [Explanation of symbols]

[0430] 100: Display device, 100A: Display device, 100B: Display device, 101: Layer, 110: Pixel, 110a: Sub-pixel, 110b: Sub-pixel, 110c: Sub-pixel, 110d: Sub-pixel, 110d1: Sub-pixel, 110d2: Sub-pixel, 110d3: Sub-pixel, 111: Pixel electrode, 111a: Pixel electrode, 111b: Pixel electrode, 111c: Pixel electrode, 111d: Pixel electrode, 112: Conductive layer, 112a: Conductive layer, 112b: Conductive layer, 112c: Conductive layer, 113: Layer, 114: Layer, 115: Common electrode, 118: Sacrificial layer, 118A: Sacrificial layer, 119: Sacrificial layer, 119A: Sacrificial layer, 1 20: Substrate, 121: Insulator, 122: Resin layer, 123: Conductive layer, 123a: Conductive layer, 123b: Conductive layer, 124: Insulator, 124a: Insulator, 124A: Insulating film, 124b: Insulator, 124B: Insulating film, 125: Colored layer, 125a: Colored layer, 125b: Colored layer, 125c: Colored layer, 126: Insulating layer, 128a: Pixel, 128b: Pixel, 130: Light-emitting device, 130a: Light-emitting device, 130b: Light-emitting device, 130c: Light-emitting device, 130d: Light-emitting device, 131: Protective layer, 133: Gap, 140: Connection part, 142: Adhesive layer, 148: Light-shielding layer, 151: Substrate, 152: Substrate, 162: Display unit, 164: Circuit, 165: Wiring, 166: Conductive layer, 172: FPC, 173: IC, 181a: Hole injection layer, 181A: Hole injection layer, 182a: Hole transport layer, 182A: Hole transport layer, 182b: Hole transport layer, 182B: Hole transport layer, 183a: Light-emitting layer, 183A: Light-emitting layer, 183b: Light-emitting layer, 183B: Light-emitting layer, 184a: Electron transport layer, 184A: Electron transport layer, 184b: Electron transport layer, 184B: Electron transport layer, 190: Resist mask, 191: Intermediate layer, 191A: Intermediate layer, 192: Light-emitting unit, 194: Light-emitting unit, 201: Transistor, 204: Connector, 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, 228: Region, 231: Semiconductor layer, 231i: Channel formation region, 231n: Low-resistance region, 242: Connection layer, 321: Insulating layer, 331: Plug, 362: Insulating layer, 363: Insulating layer, 364: Adhesive layer, 400: Display device, 400A: Display device,400B: Display device, 400C: Display device, 401: Substrate, 402: Substrate, 410: Transistor, 411: Conductive layer, 412: Low resistance region, 413: Insulating layer, 414: Insulating layer, 415: Element isolation layer, 420: Transistor, 421: Semiconductor layer, 423: Insulating layer, 424: Conductive layer, 425: Conductive layer, 426: Insulating layer, 427: Conductive layer, 428: Insulating layer, 429: Insulating layer, 432: Insulating layer, 440: Capacitive element, 441: Conductive layer, 442: Conductive layer, 443: Insulating layer, 451: Conductive layer, 452: Conductive layer, 461: Insulating layer, 461a: Insulating layer, 461b: Insulating layer, 4 62: Insulating layer, 463: Insulating layer, 465: Insulating layer, 471: Plug, 471a: Conductive layer, 471b: Conductive layer, 474: Plug, 480: Display module, 481: Display unit, 482: Circuit unit, 483: Pixel circuit unit, 483a: Pixel circuit, 484: Pixel unit, 484a: Pixel, 485: Terminal unit, 486: Wiring unit, 490: FPC, 500: Display device, 501: Electrode, 502: Electrode, 512Q_1: Light-emitting unit, 512Q_2: Light-emitting unit, 512Q_3: Light-emitting unit, 521: Layer, 522: Layer, 523Q_1: Light-emitting layer, 523Q_2: Light-emitting layer, 523Q_ 3: Light-emitting layer, 524: Layer, 525: Layer, 531: Intermediate layer, 540: Protective layer, 545B: Coloring layer, 545G: Coloring layer, 545R: Coloring layer, 550W: Light-emitting device, 6500: Electronic device, 6501: Housing, 6502: Display unit, 6503: Power button, 6504: Button, 6505: Speaker, 6506: Microphone, 6507: Camera, 6508: Light source, 6510: Protective component, 6511: Display panel, 6512: Optical component, 6513: Touch sensor panel, 6515: FPC, 6516: IC, 6517: Printed circuit board, 6518: Battery, 7000: Display unit 7100: Television equipment, 7101: Enclosure, 7103: Stand, 7111: Remote control, 7200: Notebook personal computer, 7211: Enclosure, 7212: Keyboard, 7213: Pointing device, 7214: External connection port, 7300: Digital signage, 7301: Enclosure, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 9000: Enclosure, 9001: Display unit, 9003: Speaker, 9005: Operation keys, 9006: Connection terminal, 9007: Sensor9008: Microphone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9101: Personal Digital Assistant, 9102: Personal Digital Assistant, 9200: Personal Digital Assistant, 9201: Personal Digital Assistant

Claims

1. It comprises a first light-emitting device, a second light-emitting device, a first colored layer, a second colored layer, a first insulator, a second insulator, and a third insulator. The first colored layer is placed superimposed on the first light-emitting device. The second colored layer is arranged superimposed on the second light-emitting device. The first light-emitting device and the second light-emitting device have the function of emitting white light, The first colored layer has the function of transmitting visible light of a different color from the second colored layer. The first light-emitting device comprises a first pixel electrode, a first light-emitting unit on the first pixel electrode, a first charge generation layer on the first light-emitting unit, a second light-emitting unit on the first charge generation layer, a common layer on the second light-emitting unit, and a common electrode on the common layer. The second light-emitting device comprises a second pixel electrode, a third light-emitting unit on the second pixel electrode, a second charge generation layer on the third light-emitting unit, a fourth light-emitting unit on the second charge generation layer, the common layer on the fourth light-emitting unit, and the common electrode on the common layer. The first insulator is in contact with at least a portion of the side surface of the first light-emitting device. The second insulator is in contact with at least a portion of the side surface of the second light-emitting device. The first insulator and the second insulator are placed on the third insulator. The third insulator is positioned to cover the ends of the first pixel electrode and the ends of the second pixel electrode. The first insulator and the second insulator each have a first layer and a second layer on the first layer. In the first insulator, The side surface of the first layer is in contact with at least a portion of the side surface of the first light-emitting device. The lower surface of the first layer is in contact with at least a portion of the third insulator. The side and bottom surfaces of the second layer are in contact with at least a portion of the first layer. In the second insulator, The side surface of the first layer is in contact with at least a portion of the side surface of the second light-emitting device. The lower surface of the first layer is in contact with at least a portion of the third insulator. The sides and bottom surface of the second layer are in contact with at least a portion of the first layer. Display device.

2. In Claim 1, The common layer has an electron injection layer. Display device.

3. In claim 1 or 2, The first light-emitting unit has a first light-emitting layer, The third light-emitting unit has a second light-emitting layer, The second light-emitting unit has a third light-emitting layer, The fourth light-emitting unit has a fourth light-emitting layer, Display device.

4. In claim 3, The first light-emitting layer has the same material as the second light-emitting layer. The third light-emitting layer is made of the same material as the fourth light-emitting layer. Display device.

5. In claim 3 or 4, The first charge generation layer has the same material as the second charge generation layer. Display device.

6. In any one of claims 3 to 5, The first light-emitting unit comprises a first hole injection layer, a first hole transport layer, and a first electron transport layer. The aforementioned second light-emitting unit comprises a second hole transport layer and a second electron transport layer, The third light-emitting unit comprises a second hole injection layer, a third hole transport layer, and a third electron transport layer. The fourth light-emitting unit comprises a fourth hole transport layer and a fourth electron transport layer, The first insulator is in contact with the side surface of the first hole injection layer, the side surface of the first hole transport layer, the side surface of the first light-emitting layer, the side surface of the first electron transport layer, the side surface of the first charge generation layer, the side surface of the second hole transport layer, the side surface of the third light-emitting layer, and the side surface of the second electron transport layer. The second insulator is in contact with the side surface of the second hole injection layer, the side surface of the third hole transport layer, the side surface of the second light-emitting layer, the side surface of the third electron transport layer, the side surface of the second charge generation layer, the side surface of the fourth hole transport layer, the side surface of the second light-emitting layer, and the side surface of the fourth electron transport layer. Display device.

7. In any one of claims 1 to 6, The first layer contains aluminum oxide, The second layer comprises silicon nitride, Display device.

8. In any one of claims 3 to 6, The side surface of the first light-emitting layer and the side surface of the second light-emitting layer are facing each other. The distance between the side surface of the first light-emitting layer and the side surface of the second light-emitting layer is 8 μm or less. Display device.

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

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

Images