Indication device

Abstract

To provide a display device with high display quality. To provide a highly reliable display device. To provide a display device with low power consumption. To provide a display device that is easily made high-resolution. To provide a display device that combines high display quality and high resolution. To provide a display device with high contrast. [Solution] A display device comprising a first pixel, a second pixel arranged adjacent to the first pixel, and a first insulating layer, wherein the first pixel comprises a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer, and the second pixel comprises a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer, wherein the side surface of the first EL layer and the side surface of the second EL layer have regions in contact with the first insulating layer, the side surface of the first pixel electrode is covered by the first EL layer, and the side surface of the second pixel electrode is covered by the second EL layer.

Description

[Technical Field]

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

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

[0003] In recent years, there has been a growing demand for higher resolution display panels. Examples of devices requiring high-resolution display panels include smartphones, tablet devices, and notebook computers. Furthermore, stationary display devices such as television sets and monitors also require higher resolution and greater detail. Among the devices demanding the highest resolution are those used for virtual reality (VR) and augmented reality (AR).

[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 electroluminescent (OLED) element is a layer containing a light-emitting organic compound sandwiched between a pair of electrodes. By applying a voltage between the pair of electrodes, light can be obtained from the light-emitting organic compound. Because a display device using such an OLED 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 OLED element is disclosed in Patent Document 1.

[0006] Patent document 2 discloses a display device for VR using an organic EL device. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2002-324673 [Patent Document 2] International Publication No. 2018 / 087625 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] One aspect of the present invention aims to provide a display device with high display quality. One aspect of the present invention aims to provide a highly reliable display device. One aspect of the present invention aims to provide a display device with low power consumption. One aspect of the present invention aims to provide a display device that is easily made high-resolution. One aspect of the present invention aims to provide a display device that combines high display quality and high resolution. One aspect of the present invention aims to provide a display device with high contrast.

[0009] One aspect of the present invention is to provide a display device having a novel configuration or a method for manufacturing a display device. One aspect of the present invention is to provide a method for manufacturing the above-described display device with high yield. One aspect of the present invention is to at least reduce at least one of the problems of the prior art.

[0010] Note that the description of these problems does not prevent the existence of other problems. Note that one aspect of the present invention does not need to solve all of these problems. Note that other problems can be extracted from the descriptions in the specification, drawings, claims, etc.

Means for Solving the Problems

[0011] One aspect of the present invention is a display device having a first pixel, a second pixel disposed adjacent to the first pixel, and a first insulating layer, wherein the first pixel has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer, the second pixel has a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer, the side surfaces of the first EL layer and the second EL layer have a region in contact with the first insulating layer, the side surface of the first pixel electrode is covered by the first EL layer, and the side surface of the second pixel electrode is covered by the second EL layer.

[0012] Alternatively, one aspect of the present invention is a display device having a first pixel, a second pixel disposed adjacent to the first pixel, and a first insulating layer, wherein the first pixel has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer, the second pixel has a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer, the side surfaces of the first EL layer and the second EL layer have a region in contact with the first insulating layer, the end of the first pixel electrode is located inside the end of the first EL layer, and the end of the second pixel electrode is located inside the end of the second EL layer.

[0013] Alternatively, one aspect of the present invention is a display device having a first pixel, a second pixel arranged adjacent to the first pixel, and a first insulating layer, wherein the first pixel has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer, and the second pixel has a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer, and the side surface of the first EL layer and the side surface of the second EL layer have regions in contact with the first insulating layer, the side surface of the first pixel electrode is in contact with the first EL layer, and the side surface of the second pixel electrode is in contact with the second EL layer.

[0014] Furthermore, in the above configuration, it is preferable that the upper surface of the first EL layer, the upper surface of the second EL layer, and the upper surface of the first insulating layer have regions that are in contact with the common electrode.

[0015] Furthermore, in the above configuration, it is preferable that the first pixel has a common layer disposed between the first EL layer and the common electrode, the second pixel has a common layer disposed between the second EL layer and the common electrode, and that the upper surface of the first EL layer, the upper surface of the second EL layer, and the upper surface of the first insulating layer have regions in contact with the common layer.

[0016] Furthermore, in the above configuration, it is preferable that, in a cross-sectional view of the display device, the first insulating layer has a region that protrudes above at least one of the upper surfaces of the first EL layer and the upper surface of the second EL layer.

[0017] Furthermore, in the above configuration, it is preferable that, in a cross-sectional view of the display device, at least one of the first EL layer and the second EL layer has a region that protrudes above the upper surface of the first insulating layer.

[0018] Furthermore, in the above configuration, it is preferable that the upper surface of the first insulating layer has a concave curved shape when viewed in cross-section of the display device.

[0019] Furthermore, in the above configuration, it is preferable that the upper surface of the first insulating layer has a convex curved shape when viewed in cross-section of the display device.

[0020] Alternatively, one aspect of the present invention is a display device having a first pixel, a second pixel arranged adjacent to the first pixel, a first insulating layer, and a second insulating layer, wherein the first pixel has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer, the second pixel has a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer, the side surface of the first EL layer and the side surface of the second EL layer have regions in contact with the first insulating layer, the second insulating layer is provided in contact with the first insulating layer and arranged below the common electrode, the first insulating layer has an inorganic material, the second insulating layer has an organic material, the side surface of the first pixel electrode is covered by the first EL layer, and the side surface of the second pixel electrode is covered by the second EL layer.

[0021] Furthermore, in the above configuration, it is preferable that the upper surface of the first EL layer, the upper surface of the second EL layer, and the upper surface of the first insulating layer have regions that are in contact with the common electrode.

[0022] Furthermore, in the above configuration, it is preferable that the first pixel has a common layer disposed between the first EL layer and the common electrode, the second pixel has a common layer disposed between the second EL layer and the common electrode, and that the upper surface of the first EL layer, the upper surface of the second EL layer, and the upper surface of the first insulating layer have regions in contact with the common layer.

[0023] Furthermore, in the above configuration, it is preferable that, in a cross-sectional view of the display device, the first insulating layer has a region that protrudes above at least one of the upper surfaces of the first EL layer and the upper surface of the second EL layer.

[0024] Furthermore, in the above configuration, it is preferable that, in a cross-sectional view of the display device, at least one of the first EL layer and the second EL layer has a region that protrudes above the upper surface of the first insulating layer.

[0025] Furthermore, in the above configuration, it is preferable that the upper surface of the second insulating layer has a concave curved shape when viewed in cross-section of the display device.

[0026] Furthermore, in the above configuration, it is preferable that the upper surface of the second insulating layer has a convex curved shape when viewed in cross-section of the display device. [Effects of the Invention]

[0027] According to one aspect of the present invention, a display device with high display quality can be provided. Furthermore, a highly reliable display device can be provided. Furthermore, a display device with low power consumption can be provided. Furthermore, a display device that is easily made high-resolution can be provided. Furthermore, a display device that combines high display quality and high resolution can be provided. Furthermore, a display device with high contrast can be provided.

[0028] Furthermore, according to one aspect of the present invention, a display device having a novel configuration or a method for manufacturing a display device can be provided. Also, a method for manufacturing the above-mentioned display device with a high yield can be provided. According to one aspect of the present invention, at least one of the problems of the prior art can be mitigated.

[0029] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description in the specification, drawings, claims, etc. [Brief explanation of the drawing]

[0030] [Figure 1] Figure 1A is a top view showing an example of a display device. Figures 1B to 1D are cross-sectional views showing examples of display devices. [Figure 2] Figures 2A to 2C are cross-sectional views showing an example of a display device. [Figure 3] Figures 3A to 3C are cross-sectional views showing an example of a display device. [Figure 4] Figures 4A to 4F are cross-sectional views showing examples of methods for manufacturing a display device. [Figure 5] Figures 5A to 5D are cross-sectional views showing examples of methods for manufacturing a display device. [Figure 6] Figures 6A to 6C are cross-sectional views showing examples of methods for manufacturing a display device. [Figure 7] Figures 7A to 7C are cross-sectional views showing examples of methods for manufacturing a display device. [Figure 8] Figures 8A and 8B are cross-sectional views showing an example of a display device. [Figure 9] Figures 9A and 9B are cross-sectional views showing an example of a display device. [Figure 10] Figure 10 is a perspective view showing an example of a display device. [Figure 11] Figure 11A is a cross-sectional view showing an example of a display device. Figures 11B and 11C are cross-sectional views showing an example of a transistor. [Figure 12] Figures 12A and 12B are perspective views showing an example of a display module. [Figure 13] Figure 13 is a cross-sectional view showing an example of a display device. [Figure 14] Figure 14 is a cross-sectional view showing an example of a display device. [Figure 15] Figure 15 is a cross-sectional view showing an example of a display device. [Figure 16] Figure 16 is a cross-sectional view showing an example of a display device. [Figure 17] Figures 17A to 17F show examples of the configuration of a light-emitting element. [Figure 18] Figures 18A and 18B show examples of electronic devices. [Figure 19] Figures 19A to 19D show examples of electronic devices. [Figure 20] Figures 20A to 20F show examples of electronic devices. [Figure 21] Figures 21A to 21F show examples of electronic devices. [Figure 22] Figures 22A and 22B are photographs of the display panel according to the embodiment. [Figure 23] Figures 23A to 23C show the spectral measurement results for the example. [Figure 24] Figures 24A to 24C show the spectral measurement results for the example. [Modes for carrying out the invention]

[0031] The embodiments will be described below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the embodiments can be implemented in many different ways, and their form and details can be modified in various ways without departing from the spirit and scope thereof. Accordingly, the present invention shall not be construed as being limited to the contents of the following embodiments.

[0032] In the configuration of the invention described below, the same reference numerals are used in common across different drawings for identical parts or parts having similar functions, and repeated explanations are omitted. Furthermore, when referring to similar functions, the hatch patterns are the same, and reference numerals may not be assigned.

[0033] In the figures described herein, the size of each component, the thickness of the layers, or the area may be exaggerated for clarity. Therefore, the scale is not necessarily limited to those figures.

[0034] In this specification, the term "top view" may be replaced with the term "plan view." Similarly, in this specification, the term "top view" may be replaced with the term "plan view."

[0035] Furthermore, ordinal numbers such as "the first," "the second," etc., used in this specification are added to avoid confusion of constituent elements and do not imply any numerical limitation.

[0036] Furthermore, in this specification, the terms "film" and "layer" are interchangeable. For example, the terms "conductive layer" or "insulating layer" may be interchangeable with the terms "conductive film" or "insulating film."

[0037] In this specification, the term "EL layer" refers to a layer (also called a light-emitting layer) provided between a pair of electrodes of a light-emitting element and containing at least a light-emitting substance, or a laminate including a light-emitting layer.

[0038] In this specification, a display panel, which is one form of a display device, has the function of displaying (outputting) images or the like on its display surface. Therefore, a display panel is one form of an output device.

[0039] Furthermore, in this specification, a display panel on which a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) is attached, or on which an IC is mounted on the board using a COG (Chip On Glass) method, may be referred to as a display panel module, display module, or simply a display panel.

[0040] A light-emitting element according to one aspect of the present invention may have a layer containing a material with high hole injection properties, a material with high hole transport properties, a material with high electron transport properties, a material with high electron injection properties, and a bipolar material, etc.

[0041] Furthermore, the light-emitting layer, as well as the layers containing materials with high hole injection, high hole transport, high electron transport, high electron injection, and bipolar materials, may each contain inorganic compounds such as quantum dots, or polymer compounds (oligomers, dendrimers, polymers, etc.). For example, quantum dots can be used in the light-emitting layer to function as a light-emitting material.

[0042] Furthermore, as quantum dot materials, colloidal quantum dot materials, alloy-type quantum dot materials, core-shell type quantum dot materials, and core-type quantum dot materials can be used. Materials containing element groups 12 and 16, 13 and 15, or 14 and 16 may also be used. Alternatively, quantum dot materials containing elements such as cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium, lead, gallium, arsenic, and aluminum may be used.

[0043] 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.

[0044] In this specification, 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. Also, 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.

[0045] 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.

[0046] 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.

[0047] Furthermore, when comparing the aforementioned white light-emitting devices (single or tandem structure) with SBS structure light-emitting devices, SBS structure light-emitting devices can consume less power than white light-emitting devices. If you want to keep power consumption low, it is preferable to use SBS structure light-emitting devices. On the other hand, white light-emitting devices are preferable because their manufacturing process is simpler than that of SBS structure light-emitting devices, which can lead to lower manufacturing costs or higher manufacturing yields.

[0048] (Embodiment 1) This embodiment describes an example of the configuration of a display device according to one aspect of the present invention, and an example of a method for manufacturing the display device.

[0049] One aspect of the present invention is a display device having light-emitting elements (also called light-emitting devices). The display device has two light-emitting elements that emit light of at least different colors. Each light-emitting element has a pair of electrodes and an EL layer between them. As the light-emitting elements, electroluminescent elements such as organic EL elements and inorganic EL elements can be used. In addition, light-emitting diodes (LEDs) can be used. In one aspect of the present invention, the light-emitting element is preferably an organic EL element. The two or more light-emitting elements that emit different colors each have an EL layer containing a different material. For example, a full-color display device can be realized by having three types of light-emitting elements that emit red (R), green (G), or blue (B) light, respectively.

[0050] When differentiating EL layers between light-emitting elements of different colors, it is known that they are formed by a vapor deposition method using a shadow mask such as a metal mask. However, with this method, deviations from the design occur in the shape and position of the island-like organic film 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 deposited film due to vapor scattering, making it difficult to achieve high resolution and high aperture ratio. In addition, dust may be generated during vapor deposition due to material adhering to the metal mask. Such dust may cause pattern defects in the light-emitting elements. There is also a possibility of short circuits caused by the dust. Furthermore, a cleaning process for the material adhering to the metal mask is required. For this reason, measures have been taken to artificially increase resolution (also called pixel density) by applying special pixel arrangement methods such as PenTile arrangement.

[0051] One aspect of the present invention involves processing the EL layer into a fine pattern without using a shadow mask such as a metal mask. This makes it possible to realize a display device with high resolution and a large aperture ratio, which has been difficult to achieve until now. Furthermore, since the EL layer can be differentiated, it is possible to realize a display device with extremely vivid colors, high contrast, and high display quality.

[0052] For simplicity, this section describes the process of creating separate EL layers for two-color light-emitting elements. First, a first EL film and a first sacrificial film are laminated and formed, covering the pixel electrodes. Next, a resist mask is formed on the first sacrificial film. Then, using the resist mask, a portion of the first sacrificial film and a portion of the first EL film are etched to form the first EL layer and the first sacrificial layer on the first EL layer.

[0053] Next, a second EL film and a second sacrificial film are laminated together. Then, using a resist mask, a portion of the second sacrificial film and a portion of the second EL film are etched to form a second EL layer and a second sacrificial layer on the second EL layer. Next, using the first and second sacrificial layers as masks, the pixel electrodes are processed to form a first pixel electrode superimposed on the first EL layer and a second pixel electrode superimposed on the second EL layer. In this way, the first and second EL layers can be created separately. Finally, by removing the first and second sacrificial layers and forming a common electrode, two-color light-emitting elements can be created separately.

[0054] Furthermore, by repeating the above process, it is possible to create EL layers with three or more light-emitting elements, thereby realizing a display device with three or more light-emitting elements.

[0055] At the edges of the EL layer, a step difference occurs due to the presence of pixel electrodes and the EL layer in one area and the absence of pixel electrodes and the EL layer in another. When forming a common electrode on the EL layer, the step difference at the edge of the EL layer may result in poor coverage of the common electrode, raising concerns that the common electrode may be cut. Furthermore, there is a concern that the common electrode may become thinner, leading to an increase in electrical resistance.

[0056] Furthermore, when the edges of the pixel electrodes are roughly aligned with the edges of the EL layer, and when the edges of the pixel electrodes are located outside the edges of the EL layer, a short circuit may occur between the common electrode and the pixel electrode when forming a common electrode on the EL layer.

[0057] One aspect of the present invention involves providing an insulating layer between the first EL layer and the second EL layer, thereby reducing the surface irregularities on which the common electrode is provided. This improves the coverage of the common electrode at the edges of the first EL layer and the second EL layer, enabling good conductivity of the common electrode. Furthermore, it suppresses short circuits between the common electrode and the pixel electrode.

[0058] When EL layers of different colors are adjacent, it is difficult to reduce the spacing between adjacent EL layers to less than 10 μm using, for example, a formation method using a metal mask. However, with the method described above, the spacing can be narrowed to 3 μm or less, 2 μm or less, or even 1 μm or less. For example, by using an exposure apparatus for LSIs, the spacing can be narrowed to 500 nm or less, 200 nm or less, 100 nm or less, and even 50 nm or less. This significantly reduces the area of ​​the non-emitting region that may exist between two light-emitting elements, making it possible to approach an aperture ratio of 100%. For example, an aperture ratio of 50% or more, 60% or more, 70% or more, 80% or more, and even 90% or more, can be achieved, and even less than 100%.

[0059] Furthermore, the pattern of the EL layer itself can be made extremely small compared to when a metal mask is used. Also, for example, when a metal mask is used to create different EL layers, variations in thickness occur between the center and edges of the pattern, so the effective area that can be used as an emitting region is small relative to the total area of ​​the pattern. On the other hand, with the above manufacturing method, the pattern is formed by processing a film deposited to a uniform thickness, so the thickness can be made uniform within the pattern, and even if the pattern is fine, almost the entire area can be used as an emitting region. Therefore, with the above manufacturing method, it is possible to achieve both high resolution and a high aperture ratio.

[0060] Thus, the above manufacturing method makes it possible to realize a display device that integrates fine light-emitting elements. Therefore, it is not necessary to apply a special pixel arrangement method such as the pentile method to artificially increase the resolution. Thus, it is possible to realize a display device with a resolution of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, 3000 ppi or more, or even 5000 ppi or more, using a so-called stripe arrangement in which R, G, and B are each arranged in one direction.

[0061] In the following section, a more specific configuration example and manufacturing method example of a display device according to one aspect of the present invention will be described with reference to the drawings.

[0062] [Configuration Example 1] Figure 1A shows a schematic top view of a display device 100 according to one embodiment of the present invention. The display device 100 has multiple red-emitting light-emitting elements 110R, green-emitting light-emitting elements 110G, and blue-emitting light-emitting elements 110B. In Figure 1A, the labels R, G, and B are added within the light-emitting area of ​​each light-emitting element to simplify the distinction between them.

[0063] The light-emitting elements 110R, 110G, and 110B are each arranged in a matrix. Pixel 103, shown in Figure 1A, exhibits a so-called stripe arrangement, where light-emitting elements of the same color are arranged in one direction. Note that the arrangement method of the light-emitting elements is not limited to this; other arrangement methods such as delta arrangements and zigzag arrangements may also be applied, and pentile arrangements can also be used.

[0064] It is preferable to use EL elements such as OLED (Organic Light Emitting Diode) or QLED (Quantum-dot Light Emitting Diode) as the light-emitting elements 110R, 110G, and 110B. Examples of light-emitting materials for EL elements include fluorescent materials, phosphorescent materials, inorganic compounds (such as quantum dot materials), and thermally activated delayed fluorescence (TADF) materials.

[0065] Figure 1B is a schematic cross-sectional view corresponding to the dashed lines A1-A2 and C1-C2 in Figure 1A, and Figure 1C is a schematic cross-sectional view corresponding to the dashed line B1-B2.

[0066] Figure 1B shows cross-sections of light-emitting elements 110R, 110G, and 110B. In Figure 1B, light-emitting elements 110R, 110G, and 110B are provided on a substrate 101. Light-emitting element 110R has a pixel electrode 111R, an EL layer 112R, a common layer 114, and a common electrode 113. Light-emitting element 110G has a pixel electrode 111G, an EL layer 112G, a common layer 114, and a common electrode 113. Light-emitting element 110B has a pixel electrode 111B, an EL layer 112B, a common layer 114, and a common electrode 113. An insulating layer 131 is provided between adjacent light-emitting elements. In the following, when describing matters common to pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B, the symbols attached to the reference numerals may be omitted, and it may be referred to simply as pixel electrode 111. Furthermore, when explaining matters common to EL layer 112R, EL layer 112G, and EL layer 112B, the symbols attached to the reference numerals may be omitted, and the explanation may simply refer to it as EL layer 112. Also, in the following, when explaining matters common to light-emitting elements 110R, 110G, and 110B, the symbols attached to the reference numerals may be omitted, and the explanation may simply refer to it as light-emitting element 110.

[0067] Figure 2A shows a magnified view of the area enclosed by the dashed-dotted square in Figure 1B. Figure 2B also shows a magnified view of the area enclosed by the dashed-dotted square in Figure 1C.

[0068] In this specification, the thickness of layers and films may be depicted as thicker in the original drawings for clarity. Furthermore, the distances between components of the display device may differ in the enlarged drawings. For example, in Figure 2A, the distance between the edge of the pixel electrode 111R and the edge of the EL layer 112R, and the distance between the edge of the pixel electrode 111B and the edge of the EL layer 112B are depicted as wider. Also, the spacing between the components of the light-emitting element 110B and the components of the light-emitting element 110R is depicted as wider.

[0069] The light-emitting element 110R has an EL layer 112R between the pixel electrode 111R and the common electrode 113. The EL layer 112R has a light-emitting organic compound that emits at least red light. The light-emitting element 110G has an EL layer 112G between the pixel electrode 111G and the common electrode 113. The EL layer 112G has a light-emitting organic compound that emits at least green light. The light-emitting element 110B has an EL layer 112B between the pixel electrode 111B and the common electrode 113. The EL layer 112B has a light-emitting organic compound that emits at least blue light.

[0070] In Figures 1B and 1C, the common layer 114 is provided between the pixel electrode 111 and the common electrode 113 of the light-emitting element 110. The common layer is provided as a continuous layer common to each light-emitting element. Note that the light-emitting element 110 may also be configured without the common layer 114.

[0071] Figure 1A also shows a connecting electrode 111C that is electrically connected to the common electrode 113. The connecting electrode 111C is supplied with a potential (e.g., anode potential or cathode potential) to the common electrode 113. The connecting electrode 111C is located outside the display area where the light-emitting elements 110R and the like are arranged. In Figure 1A, the common electrode 113 is shown with a dashed line.

[0072] The connecting electrode 111C can be provided along the outer perimeter of the display area. For example, it may be provided along one side of the outer perimeter of the display area, or along two or more sides of the outer perimeter of the display area. That is, if the top surface shape of the display area is rectangular, the top surface shape of the connecting electrode 111C can be a strip, L-shape, U-shape (angle bracket shape), or square, etc.

[0073] Figure 1B also shows a cross-section corresponding to the dashed line C1-C2 shown in Figure 1A. In the cross-section shown at C1-C2, a region 130 is provided where the connecting electrode 111C and the common electrode 113 are electrically connected. In Figure 1B, an example is shown in which a common layer 114 is provided between the connecting electrode 111C and the common electrode 113, but as shown in Figure 1D, the region 130 may be configured without a common layer 114. In Figure 1D, the connecting electrode 111C and the common electrode 113 can be in contact, which can further reduce the contact resistance.

[0074] In region 130, a common electrode 113 is provided on the connecting electrode 111C, and a protective layer 121 is provided covering the common electrode 113.

[0075] EL layer 112R, EL layer 112G, and EL layer 112B each have a layer (luminescent layer) containing a luminescent organic compound. The luminescent layer may contain one or more types of compounds (host material, assist material) in addition to the luminescent substance (guest material). As the host material and assist material, one or more types of materials having an energy gap larger than the energy gap of the luminescent substance (guest material) can be selected and used. It is preferable to use a combination of compounds that form an excited complex as the host material and assist material. In order to efficiently form an excited complex, it is particularly preferable to combine a compound that readily accepts holes (hole transport material) and a compound that readily accepts electrons (electron transport material).

[0076] The light-emitting element can be made from either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds (such as quantum dot materials).

[0077] Each of the EL layers 112R, 112G, and 112B may have, in addition to the light-emitting layer, one or more of the following: an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer.

[0078] Pixel electrodes 111R, 111G, and 111B are provided for each light-emitting element. A common electrode 113 is provided as a continuous layer common to each light-emitting element. A conductive film that is transparent to visible light is used on either each pixel electrode or the common electrode 113, and a conductive film that is reflective is used on the other. By making each pixel electrode transparent and the common electrode 113 reflective, a bottom-emission type display device can be made. Conversely, by making each pixel electrode reflective and the common electrode 113 transparent, a top-emission type display device can be made. Furthermore, by making both each pixel electrode and the common electrode 113 transparent, a dual-emission type display device can be made.

[0079] It is preferable to use a conductive film that is reflective to visible light for the pixel electrode 111. For example, silver, aluminum, titanium, tantalum, molybdenum, platinum, gold, titanium nitride, tantalum nitride, etc. can be used for the conductive film. Alternatively, an alloy can be used for the pixel electrode 111. For example, an alloy containing silver can be used. As an alloy containing silver, for example, an alloy containing silver, palladium, and copper can be used. Alternatively, for example, an alloy containing aluminum can be used. Furthermore, two or more layers of these materials may be used.

[0080] Furthermore, as the pixel electrode 111, a conductive film that is transparent to visible light can be used on a conductive film that is reflective to visible light. Conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, indium tin oxide containing silicon, and indium zinc oxide containing silicon can be used as the conductive material that is transparent to visible light. Alternatively, an oxide of a conductive material that is reflective to visible light may be used, and this oxide may be formed by oxidizing the surface of a conductive material that is reflective to visible light. Specifically, for example, titanium oxide may be used. Titanium oxide may be formed, for example, by oxidizing the surface of titanium.

[0081] By providing an oxide on the surface of the pixel electrode 111, oxidation reactions with the pixel electrode 111 during the formation of the EL layer 112 can be suppressed.

[0082] Furthermore, by laminating a conductive film that is transparent to visible light on a conductive film that is reflective to visible light as the pixel electrode 111, the conductive film that is transparent to visible light can function as an optical adjustment layer.

[0083] The optical path length can be adjusted by having an optical adjustment layer in the pixel electrode 111. The optical path length in each light-emitting element corresponds, for example, to the sum of the thickness of the optical adjustment layer and the thickness of the layer provided below the film containing the luminescent compound in the EL layer 112.

[0084] In light-emitting elements, a microcavity structure (micro-resonator structure) can be used to vary the optical path length, thereby intensifying light of a specific wavelength. This makes it possible to realize a display device with improved color purity.

[0085] For example, a microcavity structure can be realized by varying the thickness of the EL layer 112 in each light-emitting element. For instance, the EL layer 112R of the light-emitting element 110R that emits the longest wavelength light can be made the thickest, while the EL layer 112B of the light-emitting element 110B that emits the shortest wavelength light can be made the thinnest. However, this is not limited to this configuration, and the thickness of each EL layer can be adjusted by considering the wavelength of light emitted by each light-emitting element, the optical properties of the layers constituting the light-emitting element, and the electrical properties of the light-emitting element.

[0086] The upper surface and edges of the pixel electrode 111 are covered by the EL layer 112. Preferably, the edges of the EL layer 112 are located outside the edges of the pixel electrode 111.

[0087] Since the EL layer 112 covers the upper surface and edges of the pixel electrode 111, the processes of forming the EL layer 112, forming the insulating layer 131, etc., can be carried out without exposing the pixel electrode 111.

[0088] During the etching process for forming the EL layer 112 or the insulating layer 131, if the edges of the pixel electrodes 111 are exposed, corrosion may occur in the exposed areas. The products generated by the corrosion of the pixel electrodes 111 may be unstable; for example, in the case of wet etching, they may dissolve in the solution, and in the case of dry etching, there is a concern that they may scatter into the atmosphere. Dissolution of the products in the solution and scattering into the atmosphere may cause the products to adhere to, for example, the sides of the EL layer 112 and the surface of the substrate 101, potentially forming leak paths between adjacent light-emitting elements 110.

[0089] The film that becomes the EL layer 112, or the film that becomes the insulating layer 131, may have reduced adhesion in the area where the pixel electrode 111 is exposed, which may cause peeling of the film.

[0090] By covering the upper surface and edges of the pixel electrode 111 with the EL layer 112, for example, the yield of the light-emitting element 110 can be improved, and the display quality of the light-emitting element 110 can be improved.

[0091] An insulating layer 131 is provided between adjacent light-emitting elements 110. The insulating layer 131 is located between each of the EL layers 112 of the light-emitting elements 110. A common electrode 113 is also provided on the insulating layer 131.

[0092] The insulating layer 131 may be provided, for example, between two EL layers 112 that exhibit different colors. Alternatively, the insulating layer 131 may be provided, for example, between two EL layers 112 that exhibit the same color. Alternatively, the insulating layer 131 may be provided between two EL layers 112 that exhibit different colors, but not between two EL layers 112 that exhibit the same color.

[0093] The insulating layer 131 is provided, for example, between the two EL layers 112 when viewed from above.

[0094] It is preferable that the EL layer 112R, EL layer 112G, and EL layer 112B each have a region in contact with the upper surface of the pixel electrode and a region in contact with the side surface of the insulating layer 131. It is preferable that the ends of the EL layer 112R, EL layer 112G, and EL layer 112B are in contact with the side surface of the insulating layer 131.

[0095] By providing an insulating layer 131 between light-emitting elements of different colors, contact between the EL layer 112R, EL layer 112G, and EL layer 112G can be suppressed. This effectively prevents current from flowing through two adjacent EL layers and causing unintended light emission. As a result, contrast can be enhanced, and a display device with high display quality can be realized.

[0096] The insulating layer 131 comprises insulating layer 131a and insulating layer 131b. Insulating layer 131b is provided so as to be in contact with the side surfaces of each EL layer 112 of the light-emitting element 110. In cross-sectional view, insulating layer 131a is provided in contact with insulating layer 131b so as to fill the recesses of insulating layer 131b.

[0097] In Figure 1, the insulating layer 131 is arranged between the EL layers 112 of adjacent pixels so that it has a mesh-like (or grid-like, or matrix-like) shape when viewed from above.

[0098] The insulating layer 131 may be provided, for example, between two EL layers 112 that exhibit different colors. Alternatively, the insulating layer 131 may be provided, for example, between two EL layers 112 that exhibit the same color. Alternatively, the insulating layer 131 may be provided between two EL layers 112 that exhibit different colors, but not between two EL layers 112 that exhibit the same color.

[0099] The insulating layer 131 is provided, for example, between the two EL layers 112 when viewed from above.

[0100] It is preferable that the edges of the EL layer 112 have a region in contact with the insulating layer 131b.

[0101] By providing an insulating layer 131 between light-emitting elements of different colors, contact between the EL layer 112R, EL layer 112G, and EL layer 112G can be suppressed. This effectively prevents current from flowing through two adjacent EL layers and causing unintended light emission. As a result, contrast can be enhanced, and a display device with high display quality can be realized.

[0102] Furthermore, the insulating layer 131 may be formed only between pixels exhibiting different colors, without providing the insulating layer 131 between adjacent pixels exhibiting the same color. In this case, the insulating layer 131 can have a stripe shape when viewed from above. By making the insulating layer 131 stripe-shaped, the space required to form the insulating layer 131 is reduced compared to when it has a grid shape, thus increasing the aperture ratio. When the insulating layer 131 has a stripe shape, adjacent EL layers of the same color may be processed into strips so that they are continuous in the column direction.

[0103] The common layer 114 is preferably provided in contact with the upper surface of the EL layer 112, the upper surface of the insulating layer 131a, and the upper surface of the insulating layer 131b. The common electrode 113 is preferably provided in contact with the upper surface of the common layer 114. Furthermore, if the light-emitting element 110 does not have a common layer 114, the common electrode 113 is preferably provided in contact with the upper surface of the EL layer 112, the upper surface of the insulating layer 131a, and the upper surface of the insulating layer 131b.

[0104] Between adjacent light-emitting elements, a step difference occurs at the edge of the EL layer 112 due to the region where the EL layer 112 is provided and the region where the EL layer 112 is not provided. In one embodiment of the present invention, the display device has insulating layers 131a and 131b, which flatten the step difference and improve the coverage of the common electrode compared to the case where the common electrode 113 is provided in contact with the substrate 101 between adjacent light-emitting elements, thereby suppressing connection failures due to step breaks. Alternatively, it is possible to suppress the local thinning of the common electrode 113 due to the step difference, which would increase electrical resistance.

[0105] In one aspect of the present invention, by providing insulating layers 131a and 131b between adjacent EL layers 112, the surface irregularities of the common electrode 113 can be reduced, thereby improving the coverage of the common electrode 113 at the edges of the EL layer 112 and achieving good conductivity of the common electrode 113.

[0106] To improve the flatness of the surface where the common electrode 113 is formed, it is preferable that the upper surfaces of the insulating layer 131a and insulating layer 131b at the edges of the EL layer 112 roughly coincide with the upper surface of the EL layer 112. It is also preferable that the upper surface of the insulating layer 131 has a flat shape. However, the upper surfaces of the insulating layer 131a, insulating layer 131b, and EL layer 112 do not necessarily coincide. Furthermore, if the height of the upper surface of the EL layer 112 differs for EL layers 112 corresponding to different colors, it is preferable that the height of the upper surface of the insulating layer 131a roughly coincides with the height of the upper surface of the EL layer in the vicinity of each EL layer. It is also preferable that the height of the upper surface of the insulating layer 131b roughly coincides with the height of the EL layer in the region in contact with the side surface of each EL layer.

[0107] As shown in Figure 2A, the height of the upper surface of the insulating layer 131a is, for example, roughly the same as the height of the upper surface of the EL layer 112B in the vicinity of the EL layer 112B, and roughly the same as the height of the upper surface of the EL layer 112R in the vicinity of the EL layer 112R. Similarly, the height of the upper surface of the insulating layer 131b is, for example, roughly the same as the height of the upper surface of the EL layer 112B in the region in contact with the side surface of the EL layer 112B, and roughly the same as the height of the upper surface of the EL layer 112R in the region in contact with the side surface of the EL layer 112R.

[0108] Figure 2C shows an example where the shape of the insulating layer 131a, etc., differs from that in Figure 2B. In Figure 2C, the upper surface of the insulating layer 131a is lower than the height of the edge of the EL layer 112.

[0109] Figures 3A and 3B show examples where the shape of the insulating layer 131a differs from that of Figures 2A and 2B. In Figures 3A and 3B, the upper surface of the insulating layer 131a has a concave shape in the center and its vicinity.

[0110] Figure 3C shows an example where the shape of the insulating layer 131a differs from that of Figure 2B. In Figure 3C, the upper surface of the insulating layer 131a has a bulging shape in the center and its vicinity.

[0111] The insulating layer 131b has a region that is in contact with the side surface of the EL layer 112 and functions as a protective insulating layer for the EL layer 112. By providing the insulating layer 131b, it is possible to suppress the intrusion of oxygen, moisture, or their constituent elements into the interior from the side surface of the EL layer 112, resulting in a highly reliable display device.

[0112] If the width of the insulating layer 131b in the region in contact with the side surface of the EL layer 112 is large in a cross-sectional view, the spacing between the EL layers 112 may increase, resulting in a lower aperture ratio. Conversely, if the width of the insulating layer 131b is small, the effect of suppressing the intrusion of oxygen, moisture, or their constituent elements into the interior from the side surface of the EL layer 112 may be reduced. The width of the insulating layer 131b in the region in contact with the side surface of the EL layer 112 is preferably 3 nm to 200 nm, more preferably 3 nm to 150 nm, more preferably 5 nm to 150 nm, more preferably 5 nm to 100 nm, more preferably 10 nm to 100 nm, and more preferably 10 nm to 50 nm. By setting the width of the insulating layer 131b within the above range, a display device with a high aperture ratio and high reliability can be obtained.

[0113] The insulating layer 131b can be an insulating layer having an inorganic material. As the insulating layer 131b, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon oxide, silicon oxide nitride, or silicon oxide nitride can be used as a single layer or in a laminated form. In particular, aluminum oxide is preferred because it has a high selectivity ratio with the EL layer 112 during etching and has the function of protecting the EL layer 112 during the formation of the insulating layer 131b described later. In particular, by using inorganic insulating materials such as aluminum oxide, hafnium oxide, or silicon oxide formed by the ALD method as the insulating layer 131b, a film with fewer pinholes can be made, and an insulating layer 131b with excellent function in protecting the EL layer 112 can be made.

[0114] In this specification, "oxide-nitride" refers to a material in which the oxygen content is greater than the nitrogen content, and "nitride oxide" refers to a material in which the nitrogen content is greater than the oxygen content. For example, when "silicon oxynitride" is written, it refers to a material in which the oxygen content is greater than the nitrogen content, and when "silicon nitride oxide" is written, it refers to a material in which the nitrogen content is greater than the oxygen content.

[0115] The insulating layer 131b can be formed using sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), or atomic layer deposition (ALD). The ALD method, which provides good coverage, is preferably used for forming the insulating layer 131b.

[0116] The insulating layer 131a provided on the insulating layer 131b has the function of flattening the recess in the insulating layer 131b formed between adjacent light-emitting elements. In other words, the presence of the insulating layer 131a improves the flatness of the surface on which the common electrode 113 is formed. As the insulating layer 131a, an insulating layer having an organic material can be suitably used. For example, acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be applied as the insulating layer 131a. In addition, a photosensitive resin can be used as the insulating layer 131a. The photosensitive resin can be a positive-type material or a negative-type material.

[0117] By forming the insulating layer 131a using a photosensitive resin, the insulating layer 131a can be produced by only the exposure and development process.

[0118] The difference in height between the upper surface of the insulating layer 131a and the upper surface of the EL layer 112 is preferably 0.5 times or less the thickness of the insulating layer 131a, and more preferably 0.3 times or less the thickness of the insulating layer 131a. Alternatively, the insulating layer 131a may be provided such that the upper surface of the EL layer 112 is higher than the upper surface of the insulating layer 131a. Furthermore, the thickness of the insulating layer 131a is preferably 0.3 times or more, or 0.5 times or more, or 0.7 times or more the thickness of the pixel electrode 111.

[0119] Furthermore, a protective layer 121 is provided on the common electrode 113, covering the light-emitting elements 110R, 110G, and 110B. The protective layer 121 has the function of preventing impurities such as water from diffusing to each light-emitting element from above.

[0120] The protective layer 121 can be, for example, a single-layer structure or a multilayer structure including at least an inorganic insulating film. Examples of inorganic insulating films include oxide films or nitride films such as silicon oxide film, silicon oxide nitride film, silicon nitride film, silicon nitride film, aluminum oxide film, aluminum oxide nitride film, and hafnium oxide film. Alternatively, semiconductor materials such as indium gallium oxide and indium gallium zinc oxide may be used as the protective layer 121.

[0121] Furthermore, a laminated film of an inorganic insulating film and an organic insulating film can also be used as the protective layer 121. For example, it is preferable to have a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films. It is also preferable that the organic insulating film functions as a planarizing film. This makes the upper surface of the organic insulating film flat, thereby improving the coverage of the inorganic insulating film on top of it and enhancing its barrier properties. In addition, since the upper surface of the protective layer 121 is flat, it is preferable because it reduces the influence of uneven shapes caused by the structure below when a structure (e.g., a color filter, touch sensor electrodes, or lens array) is provided above the protective layer 121.

[0122] The common layer 114, like the common electrode 113, is provided across multiple light-emitting elements. The common layer 114 covers the EL layer 112R, EL layer 112G, and EL layer 112B. By having a configuration with a common layer 114, the manufacturing process can be simplified, thereby reducing manufacturing costs. The common layer 114 and the common electrode 113 can be formed continuously without intervening processes such as etching. Therefore, the interface between the common layer 114 and the common electrode can be made a clean surface, and good characteristics can be obtained in the light-emitting element.

[0123] Preferably, the EL layer 112R, EL layer 112G, and EL layer 112B each have a light-emitting layer containing a light-emitting material that emits at least one color. Furthermore, it is preferable that the common layer 114 is a layer containing one or more of the following: an electron injection layer, an electron transport layer, a hole injection layer, or a hole transport layer. In a light-emitting element where the pixel electrode is the anode and the common electrode is the cathode, the common layer 114 can be configured to include an electron injection layer, or to include both an electron injection layer and an electron transport layer.

[0124] [Example of manufacturing method 1] In the following, an example of a method for manufacturing a display device according to one aspect of the present invention will be described with reference to the drawings. Here, the display device 100 shown in the above configuration example will be used as an example. Figures 4A to 7C are schematic cross-sectional views of each step in the method for manufacturing the display device illustrated below.

[0125] Thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum deposition, pulsed laser deposition (PLD), and atomic layer deposition (ALD). CVD methods include plasma-enhanced CVD (PECVD) and thermal CVD. One type of thermal CVD is metal-organic vapor deposition (MOCVD).

[0126] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating.

[0127] Furthermore, when processing the thin films that constitute the display device, photolithography or the like can be used. In addition, the thin films may be processed by nanoimprint lithography, sandblasting, lift-off lithography, or the like. Alternatively, island-shaped thin films may be directly formed by a film deposition method using a shielding mask such as a metal mask.

[0128] 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.

[0129] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture thereof. Other options include ultraviolet light, KrF laser light, or ArF laser light. Exposure may also be performed using immersion lithography. Furthermore, extreme ultraviolet (EUV) light or X-rays may be used as the light source for exposure. An electron beam can also be used instead of the light source. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because it allows for extremely fine processing. Note that a photomask is not required when exposure is performed by scanning a beam such as an electron beam.

[0130] For etching thin films, methods such as dry etching, wet etching, and sandblasting can be used.

[0131] [Preparation of circuit board 101] As the substrate 101, a substrate having at least sufficient heat resistance to withstand subsequent heat treatment can be used. When an insulating substrate is used as the substrate 101, glass substrates, quartz substrates, sapphire substrates, ceramic substrates, organic resin substrates, etc., can be used. In addition, semiconductor substrates such as single-crystal semiconductor substrates made of silicon or silicon carbide, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, and SOI substrates can be used.

[0132] In particular, it is preferable to use a substrate 101 on which a semiconductor circuit including semiconductor elements such as transistors is formed on the semiconductor substrate or insulating substrate. Note that for clarity, the details of the semiconductor circuit are not shown in Figure 4, etc. The semiconductor circuit preferably comprises, for example, a pixel circuit, a gate line driving circuit (gate driver), a source line driving circuit (source driver), etc. In addition to the above, it may also include an arithmetic circuit, a memory circuit, etc.

[0133] Next, a conductive film that will become the pixel electrode 111 is deposited on the substrate 101. Subsequently, a portion of the conductive film is etched to form the pixel electrode 111R, pixel electrode 111G, pixel electrode 111B, and connecting electrode 111C on the substrate 101 (Figure 4A).

[0134] When using a conductive film that is reflective to visible light as a pixel electrode, it is preferable to use a material (such as silver or aluminum) that has the highest possible reflectivity across the entire wavelength range of visible light. This not only improves the light extraction efficiency of the light-emitting element but also enhances color reproduction.

[0135] [Formation of EL film 112Rf] Next, an EL film 112Rf, which will later become the EL layer 112R, is deposited on the pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B.

[0136] The EL film 112Rf has a film containing at least a luminescent compound. In addition, it may have a structure in which one or more films functioning as electron injection layers, electron transport layers, charge generation layers, hole transport layers, or hole injection layers are laminated. The EL film 112Rf can be formed by, for example, vapor deposition, sputtering, or inkjet. However, it is not limited to these, and the above-mentioned film formation methods can be used as appropriate.

[0137] [Formation of sacrificial film 144(1)R and sacrificial film 144(2)R] Next, we will explain the process of forming the sacrificial film.

[0138] Sacrificial film 144R is the film that becomes sacrificial layer 145R. Sacrificial film 144G is the film that becomes sacrificial layer 145G. Sacrificial film 144B is the film that becomes sacrificial layer 145B. Sacrificial layers 145R, 145G, and 145B are sometimes collectively referred to as sacrificial layer 145. A single-layer structure may be used for sacrificial layer 145, or a multilayer structure of two or more layers may be used.

[0139] The following example shows the use of a two-layer sacrificial layer.

[0140] In the example shown below, a stacked structure of sacrificial film 144(1)R and sacrificial film 144(2)R is used as sacrificial film 144R, a stacked structure of sacrificial film 144(1)G and sacrificial film 144(2)G is used as sacrificial film 144G, and a stacked structure of sacrificial film 144(1)B and sacrificial film 144(2)B is used as sacrificial film 144B.

[0141] Sacrificial film 144(1)R is the film that becomes sacrificial layer 145(1)R, and sacrificial film 144(2)R is the film that becomes sacrificial layer 145(2)R. Sacrificial film 144(1)G is the film that becomes sacrificial layer 145(1)G, and sacrificial film 144(2)G is the film that becomes sacrificial layer 145(2)G. Sacrificial film 144(1)B is the film that becomes sacrificial layer 145(1)B, and sacrificial film 144(2)B is the film that becomes sacrificial layer 145(2)B.

[0142] The sacrificial film formation process begins by forming a sacrificial film 144(1)R over the EL film 112Rf. The sacrificial film 144(1)R is provided in contact with the upper surface of the connecting electrode 111C. Subsequently, a sacrificial film 144(2)R is formed on top of the sacrificial film 144(1)R.

[0143] For the formation of the sacrificial films 144(1)R and 144(2)R, for example, sputtering, ALD (thermal ALD, PEALD), or vacuum deposition can be used. A formation method that causes less damage to the EL layer is preferred, and for the sacrificial film 144(1)R formed directly on the EL film 112Rf, it is preferable to use the ALD or vacuum deposition method rather than the sputtering method.

[0144] As the sacrificial film 144(1)R, an inorganic film such as a metal film, alloy film, metal oxide film, semiconductor film, or inorganic insulating film can be suitably used.

[0145] Furthermore, an oxide film can be used as the sacrificial film 144(1)R. Typically, oxide films or oxynitride films such as silicon oxide, silicon oxide nitride, aluminum oxide, aluminum oxide nitride, hafnium oxide, and hafnium oxide nitride can be used. Alternatively, a nitride film can be used as the sacrificial film 144(1)R. Specifically, nitrides such as silicon nitride, aluminum nitride, hafnium nitride, titanium nitride, tantalum nitride, tungsten nitride, gallium nitride, and germanium nitride can be used. Such inorganic materials can be formed using film deposition methods such as sputtering, CVD, or ALD, but it is particularly preferable to use the ALD method for the sacrificial film 144(1)R that is directly formed on the EL film 112Rf.

[0146] Furthermore, as the sacrificial film 144(1)R, 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, can be used. In particular, it is preferable to use low-melting-point materials such as aluminum or silver.

[0147] Furthermore, metal oxides such as indium gallium zinc oxide (In-Ga-Zn oxide, also denoted as IGZO) can be used as the sacrificial film 144(1)R. In addition, indium oxide, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc. can be used. Alternatively, indium tin oxide containing silicon can also be used.

[0148] Furthermore, the above-mentioned method can also be applied when element M (where M is one or more selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) is used instead of gallium. In particular, it is preferable that M be one or more selected from gallium, aluminum, or yttrium.

[0149] As the sacrificial film 144(2)R, any of the materials listed above that can be used as the sacrificial film 144(1)R can be used. Alternatively, one material can be selected as the sacrificial film 144(1)R and another as the sacrificial film 144(2)R from the materials listed above that can be used as the sacrificial film 144(1)R. Furthermore, from the materials listed above that can be used as the sacrificial film 144(1)R, one or more materials can be selected for the sacrificial film 144(1)R, and a material other than the one selected for the sacrificial film 144(1)R can be selected for the sacrificial film 144(2)R.

[0150] The sacrificial film 144(1)R can be a film with high resistance to etching treatment of each EL film, such as the EL film 112Rf, i.e., a film with a high etching selectivity ratio. Furthermore, it is particularly preferable that the sacrificial film 144(1)R be a film that can be removed by a wet etching method that causes little damage to each EL film.

[0151] Furthermore, as the sacrificial film 144(1)R, a material that is soluble in a chemically stable solvent may be used, at least for the film located on the uppermost part of the EL film 112Rf. In particular, a material soluble in water or alcohol can be suitably used for the sacrificial film 144(1)R. When forming the sacrificial film 144(1)R, it is preferable to apply it using a wet deposition method while dissolved in a solvent such as water or alcohol, and then perform a heat treatment to evaporate the solvent. At this time, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to the EL film 112Rf.

[0152] Wet film deposition methods that can be used to form the sacrificial film 144(1)R include spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating.

[0153] As the sacrificial film 144(1)R, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used.

[0154] For the sacrificial film 144(2)R, a film with a high selectivity ratio with sacrificial film 144(1)R should be used.

[0155] It is particularly preferable to use an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by the ALD method as the sacrificial film 144(1)R, and an indium-containing metal oxide such as indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO) formed by the sputtering method as the sacrificial film 144(2)R.

[0156] Furthermore, an organic film that can be used for EL films 112Rf, etc., may be used as the sacrificial film 144(2)R. For example, the same organic film used for EL films 112Rf, EL films 112Gf, or EL films 112Bf can be used as the sacrificial film 144(2)R. Using such an organic film is preferable because it allows the same deposition equipment to be used for both EL films 112Rf, etc., and EL films 112Rf, etc. Furthermore, the sacrificial layer 145(2)R can be removed simultaneously when etching EL films 112Rf, etc., thus simplifying the process.

[0157] For example, when dry etching using a fluorine-containing gas (also called a fluorine-based gas) is used to etch the sacrificial film 144(1)R, silicon, silicon nitride, silicon oxide, tungsten, titanium, molybdenum, tantalum, tantalum nitride, an alloy containing molybdenum and niobium, or an alloy containing molybdenum and tungsten can be used for the sacrificial film 144(2)R. Here, metal oxide films such as IGZO and ITO can be used for the sacrificial film 144(1)R, as they allow for a higher selectivity ratio for etching (i.e., a slower etching rate) compared to the dry etching using the above-mentioned fluorine-based gas.

[0158] [Formation of resist mask 143a] Next, a resist mask 143a is formed on the sacrificial film 144(2)R (Figure 4B). Figure 4B shows an example in which the EL film 112Rf is not deposited in region 130. When region 130 is shielded during the deposition of the EL film 112Rf, a metal mask can be used. In this case, the metal does not need to shield the pixel area of ​​the display, so there is no need to use a high-resolution mask.

[0159] The resist mask 143a can use a resist material containing a photosensitive resin, such as a positive-type resist material or a negative-type resist material.

[0160] Here, when forming a resist mask 143a on the sacrificial film 144(2)R, if defects such as pinholes exist in the sacrificial film 144(2)R, there is a risk that the EL film 112Rf may dissolve due to the solvent of the resist material. By using an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by the ALD method as the sacrificial film 144(1)R, it is possible to create a film with fewer pinholes, thereby preventing such problems from occurring.

[0161] [Etching of sacrificial film 144(1)R and sacrificial film 144(2)R] Next, portions of the sacrificial film 144(2)R and sacrificial film 144(1)R that are not covered by the resist mask 143a are removed by etching to form island-shaped or strip-shaped sacrificial layers 145(1)R and 145(2)R. Here, the sacrificial layers 145(1)R and 145(2)R are formed on the pixel electrode 111R and on the connecting electrode 111C.

[0162] Here, it is preferable to remove a portion of the sacrificial film 144(2)R by etching using the resist mask 143a to form the sacrificial layer 145(2)R, then remove the resist mask 143a, and use the sacrificial layer 145(2)R as a hard mask to etch the sacrificial film 144(1)R. For etching the sacrificial film 144(2)R, it is preferable to use etching conditions that have a high selectivity ratio with respect to the sacrificial film 144(1)R. For etching to form the hard mask, wet etching or dry etching can be used, but dry etching can suppress the reduction of the pattern. For example, if an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by the ALD method is used as the sacrificial film 144(1)R, and an indium-containing metal oxide such as indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO) formed by the sputtering method is used as the sacrificial film 144(2)R, then the sacrificial film 144(2)R formed by the sputtering method is etched to form a hard mask.

[0163] The resist mask 143a can be removed by wet etching or dry etching. In particular, it is preferable to remove the resist mask 143a by dry etching (also called plasma ashing) using oxygen gas as the etching gas.

[0164] By etching the sacrificial film 144(1)R using the sacrificial layer 145(2)R as a hard mask, the resist mask 143a can be removed while the EL film 112Rf is covered by the sacrificial film 144(1)R. This is particularly suitable when etching is performed using oxygen gas, such as plasma ashing, because contact with oxygen can adversely affect the electrical properties of the EL film 112Rf.

[0165] Next, the sacrificial layer 144(1)R is removed by etching using the sacrificial layer 145(2)R as a mask to form island-shaped or strip-shaped sacrificial layers 145(1)R. In one embodiment of the present invention, the method for manufacturing a display device may be configured without using either the sacrificial layer 145(1)R or the sacrificial layer 145(2)R.

[0166] [Etching of EL film 112Rf] Next, a portion of the EL film 112Rf that is not covered by the sacrificial layer 145(1)R is removed by etching to form island-shaped or strip-shaped EL layers 112R.

[0167] For etching the EL film 112Rf, it is preferable to use dry etching with an etching gas that does not contain oxygen as its main component. This suppresses deterioration of the EL film 112Rf and enables the realization of a highly reliable display device. Examples of etching gases that do not contain oxygen as their main component include noble gases such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He. Alternatively, a mixed gas of the above gases and an oxygen-free diluent gas can be used as the etching gas. In this case, a portion of the sacrificial layer 145(1)R may be removed during etching of the EL film 112Rf. For example, if the sacrificial layer 144(1)R has a two-layer structure, with an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by the ALD method as the lower layer, and an indium-containing metal oxide such as indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO) formed by the sputtering method as the upper layer, then the upper layer may be etched during etching of the EL film 112Rf.

[0168] Furthermore, etching of the EL film 112Rf is not limited to the above; it may also be performed by dry etching using other gases or by wet etching.

[0169] Furthermore, using an etching gas containing oxygen gas, or dry etching using oxygen gas, for etching the EL film 112Rf can increase the etching rate. Therefore, etching can be performed under low power conditions while maintaining a sufficiently fast etching rate, thereby reducing etching damage. In addition, defects such as the adhesion of reaction products generated during etching can be suppressed. For example, an etching gas to which oxygen gas is added to the above-mentioned etching gas that does not primarily contain oxygen can be used.

[0170] [Formation of EL layer 112G and EL layer 112B] Next, an EL film 112Gf, which will become the EL layer 112G, is deposited on the sacrificial layer 145(1)R, on the pixel electrode 111G, and on the pixel electrode 111B. For details on the EL film 112Gf, please refer to the description of the EL film 112Rf.

[0171] Next, a sacrificial film 144(1)G is deposited on the EL film 112Gf. For details on the sacrificial film 144(1)G, please refer to the description of the sacrificial film 144(1)R.

[0172] Next, a sacrificial film 144(2)G is deposited on the sacrificial film 144(1)G. For details on the sacrificial film 144(2)G, refer to the description of the sacrificial film 144(2)R.

[0173] Next, a resist mask 143b is formed on the sacrificial film 144(2)G (Figure 4C).

[0174] Next, sacrificial layers 145(1)G, 145(2)G, and EL layer 112G are formed (Figure 4D). The formation of sacrificial layers 145(1)G, 145(2)G, and EL layer 112G can be described by referring to the formation of sacrificial layers 145(1)R, 145(2)R, and EL layer 112R.

[0175] Next, an EL film 112Bf, which will become the EL layer 112B, is deposited on the sacrificial layer 145(2)R, the sacrificial layer 145(2)G, and the pixel electrode 111B. For details on the EL film 112Bf, refer to the description of the EL film 112Rf.

[0176] Next, a sacrificial film 144(1)B is deposited on the EL film 112Bf. For details on the sacrificial film 144(1)B, refer to the description of the sacrificial film 144(1)R.

[0177] Next, sacrificial film 144(2)B is deposited on sacrificial film 144(1)B. For details on sacrificial film 144(2)B, refer to the description of sacrificial film 144(2)R.

[0178] Next, a resist mask 143c is formed on the sacrificial film 144(2)B (Figure 4D).

[0179] Next, sacrificial layers 145(1)B, 145(2)B, and EL layer 112B are formed (Figure 4E). The formation of sacrificial layers 145(1)B, 145(2)B, and EL layer 112B can be described by referring to the formation of sacrificial layers 145(1)R, 145(2)R, and EL layer 112R.

[0180] Figure 4F shows a magnified view of the area enclosed by the dotted square in Figure 4E.

[0181] In this specification, the thickness of layers and films may be depicted as thicker in the original drawings for clarity. Furthermore, the distances between components of the display device may differ in the enlarged drawings. For example, in Figure 4F, the distance between the edge of the pixel electrode 111 and the edge of the EL layer 112 is depicted as wider. Also, the spacing between the components of the light-emitting element 110B and the components of the light-emitting element 110R is depicted as wider.

[0182] Next, sacrificial layers 145(2)R, 145(2)G, and 145(2)B (hereinafter collectively referred to as sacrificial layer 145(2)) are removed using etching or the like (Figure 5A). For etching sacrificial layer 145(2), it is preferable to use conditions that have a high selectivity ratio with sacrificial layer 145(1)R, 145(1)G, and 145(1)B (hereinafter collectively referred to as sacrificial layer 145(1)). Note that removal of sacrificial layer 145(2) is not required.

[0183] [Formation of insulating layer 131] Next, an insulating film 131bf, which will become the insulating layer 131b, is formed (Figure 5B). It is preferable to apply a film having an inorganic material as the insulating film 131bf. For example, a film having aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon oxide, silicon oxide-nitride, silicon nitride, or silicon nitride-oxide can be used as a single layer or in a laminated configuration.

[0184] The insulating film 131bf can be formed using sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), atomic layer deposition (ALD), and other methods. The ALD method, which provides good coverage, is preferably used for forming the insulating film 131bf.

[0185] As the insulating film 131bf, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon oxide, silicon oxide nitride, silicon nitride, or silicon oxide nitride can be used as a single layer or in a laminated configuration. In particular, aluminum oxide is preferred because it has a high selectivity ratio with the EL layer 112 during etching and has the function of protecting the EL layer 112 during the formation of the insulating layer 131b described later.

[0186] By forming the insulating film 131bf using the ALD method, a film with fewer pinholes can be obtained, resulting in an insulating layer 131b with excellent function in protecting the EL layer 112.

[0187] It is preferable that the insulating film 131bf is formed at a temperature lower than the heat resistance temperature of the EL layer 112.

[0188] Here, aluminum oxide is formed as the insulating film 131bf by the ALD method. The formation temperature of the insulating film 131bf by the ALD method is preferably 60°C to 150°C, more preferably 70°C to 115°C, and even more preferably 80°C to 100°C. By forming the insulating film 131bf at such temperatures, a dense insulating film can be obtained, and damage to the EL layer 112 can be reduced.

[0189] Next, an insulating film 131af, which will become the insulating layer 131a, is formed (Figure 5C). The insulating film 131af is provided so as to fill the recesses of the insulating film 131bf. The insulating film 131af is also provided so as to cover the sacrificial layer 145(1), the EL layer 112, and the pixel electrode 111. The insulating film 131af is preferably a planarized film.

[0190] It is preferable to use an insulating film having an organic material as the insulating film 131af, and it is preferable to use a resin as the organic material.

[0191] Materials that can be used for the insulating film 131af include acrylic resins, polyimide resins, epoxy resins, polyamide resins, polyimidoamide resins, siloxane resins, benzocyclobutene resins, phenolic resins, and precursors of these resins. In addition, a photosensitive resin can be used as the insulating film 131af. The photosensitive resin can be a positive-type material or a negative-type material.

[0192] By forming the insulating film 131af using a photosensitive resin, the insulating film 131af can be manufactured using only exposure and development steps, thereby reducing damage to each layer constituting the light-emitting element 110, particularly the EL layer.

[0193] As shown in Figure 5C, the insulating film 131af may have smooth irregularities that reflect the irregularities of the surface to be formed. Alternatively, as shown in Figure 5D, the insulating film 131af may be less affected by the irregularities of the surface to be formed, and may have higher flatness compared to Figure 5C.

[0194] Next, the insulating layer 131a is formed. By using a photosensitive resin as the insulating film 131af, the insulating layer 131a can be formed without providing an etching mask such as a resist mask or a hard mask. Furthermore, since the photosensitive resin can be processed only by exposure and development steps, the insulating layer 131a can be formed without using dry etching methods. Thus, the process can be simplified. In addition, damage to the EL layer due to etching of the insulating film 131af can be reduced. Furthermore, a portion of the upper part of the insulating layer 131a may be etched to adjust the surface height.

[0195] Alternatively, an insulating layer 131a may be formed by etching the upper surface of the insulating film 131af substantially uniformly. This process of uniform etching and planarization is also called etch-back.

[0196] In forming the insulating layer 131a, the exposure and development process and the etch-back process may be used in combination.

[0197] An example of a method for forming the insulating layer 131a will be explained using Figures 6A to 6C. Figure 6A shows an example in which a photosensitive resin is used as the insulating film 131af, and the insulating film 131af is processed using exposure and development steps to form the insulating layer 131ap. Figure 6B is an enlarged view of the area enclosed by the square dashed line in Figure 6A. By further etching the insulating layer 131ap shown in Figure 6B, the insulating layer 131a shown in Figure 6C can be formed.

[0198] Furthermore, the insulating layer 131ap shown in Figure 6B can also be used as the insulating layer 131a. In such cases, the light-emitting element 110 may have a configuration in which a sacrificial layer 145(1) remains between the insulating layer 131a and the EL layer 112.

[0199] Next, etching of the insulating film 131bf and the sacrificial layer 145(1) is performed (Figure 7A). At this time, it is preferable to use a method that causes as little damage as possible to the EL layer 112R, EL layer 112G, and EL layer 112B. This forms an insulating layer 131b that covers the sides of the EL layer 112R, EL layer 112G, and EL layer 112B. Figure 7B is an enlarged view of the area enclosed by the square dashed line in Figure 7A.

[0200] By using the same material for the insulating film 131bf and the sacrificial layer 145(1), etching can be performed simultaneously, which can sometimes simplify the process.

[0201] Etching of the insulating film 131bf can be performed using dry etching or wet etching methods. Etching may also be performed by ashing using oxygen plasma, etc. Furthermore, chemical mechanical polishing (CMP) may be used for etching the insulating film 131bf.

[0202] Furthermore, when etching the insulating film 131bf, it is preferable to suppress damage to the EL layer 112 due to etching. Therefore, for example, it is preferable to use a material with a high selectivity ratio between the EL layer 112 and etching as the insulating film 131bf.

[0203] By using an inorganic material as the insulating film 131bf, the selectivity ratio with respect to the EL layer 112 can be increased. Furthermore, as the insulating layer 131b, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon oxide, silicon oxide nitride, or silicon nitride oxide can be used as a single layer or in a laminated configuration. In particular, aluminum oxide is preferred because it exhibits a high selectivity ratio with respect to the EL layer 112 during etching and has the function of protecting the EL layer 112 during the formation of the insulating layer 131b, as described later. In particular, by using inorganic insulating materials such as aluminum oxide, hafnium oxide, or silicon oxide formed by the ALD method as the insulating layer 131b, a film with fewer pinholes can be formed, resulting in an insulating layer 131b with excellent protection for the EL layer 112.

[0204] When forming the insulating film 131af and insulating film 131bf, the height of their respective upper surfaces can be adjusted by the amount of etching. Here, it is preferable to adjust the amount of etching so that the insulating layer 131b covers the side surface of the EL layer 112. In particular, it is preferable to adjust the amount of etching so that the insulating layer 131b covers the side surface of the light-emitting layer of the EL layer 112.

[0205] Furthermore, the flatness of the surface of the insulating film 131af, which contains organic material, may change depending on the unevenness of the surface to be formed and the density of the pattern formed on the surface. Also, the flatness of the insulating film 131af may change depending on the viscosity of the material used as the insulating film 131af. For example, the thickness of the insulating film 131af in the region that does not overlap with the EL layer 112 may be smaller than the thickness of the insulating film 131af in the region that overlaps with the EL layer 112. In such cases, for example, by performing etch-back of the insulating film 131af, the height of the upper surface of the insulating layer 131 may become lower than the height of the upper surface of the sacrificial layer 145(1).

[0206] Furthermore, the insulating film 131af may have a concave shape (a recessed shape), a convex shape (a bulging shape), etc., in the region between the multiple EL layers 112.

[0207] [Formation of common layer 114] Next, the common layer 114 is formed. If the configuration does not have a common layer 114, the common electrode 113 can be formed by covering the EL layer 112R, EL layer 112G, and EL layer 112B.

[0208] [Formation of common electrode 113] Next, a common electrode 113 is formed on the common layer 114. The common electrode 113 can be formed, for example, by sputtering or vacuum deposition. If the common layer 114 is not provided on the connecting electrode 111C, a metal mask can be used to shield the connecting electrode 111C during the deposition of the common layer 114. In this case, the metal mask used does not need to shield the pixel area of ​​the display unit, so there is no need to use a high-resolution mask.

[0209] Through the above process, the light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B can be manufactured.

[0210] [Formation of protective layer 121] Next, a protective layer 121 is formed on the common electrode 113 (Figure 7C). For depositing the inorganic insulating film used in the protective layer 121, sputtering, PECVD, or ALD methods are preferred. The ALD method is particularly preferred because it offers excellent step coverage and is less prone to defects such as pinholes. Furthermore, for depositing the organic insulating film, the inkjet method is preferred because it allows for the formation of a uniform film in the desired area.

[0211] By following the above steps, the display device 100 shown in Figure 1A can be manufactured.

[0212] [Modified version of Configuration Example 1] Figures 8A and 8B show modified configurations of the display device 100 shown in Figure 1.

[0213] The display device 100 shown in Figure 8A has different shapes for the insulating layer 131a, insulating layer 131b, etc., compared to Figure 1B. Figure 8B shows an enlarged view of the area enclosed by the square dashed line in Figure 8A.

[0214] In Figures 8A and 8B, the display device 100 has a sacrificial layer 145(1) between the insulating layer 131b and the pixel electrode 111. This configuration can be obtained by processing the insulating layer 131ap in the configuration shown in Figure 6B such that a region covering the sacrificial layer 145(1) remains.

[0215] Figures 9A and 9B show differences in the shape of insulating layer 131a, insulating layer 131b, etc., compared to Figure 8B.

[0216] The configuration shown in Figure 9A can be obtained by using the insulating layer 131ap shown in Figure 6B as the insulating layer 131a. Alternatively, for example, the insulating layer 131a can be provided such that its upper surface is higher than the upper surface of the light-emitting layer of the EL layer 112.

[0217] The configuration shown in Figure 9B illustrates an example where the edges of the EL layer 112 do not have steps. By using the configuration shown in Figure 9B, the distance between the EL layers 112 of different light-emitting elements 110 can be reduced, and the aperture ratio of the light-emitting elements 110 can be increased in some cases.

[0218] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0219] (Embodiment 2) This embodiment describes an example of the configuration of a display device according to one aspect of the present invention.

[0220] 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, smartphones, smartwatches, tablet devices, personal digital assistants, and audio playback devices.

[0221] [Example of a display device configuration] Figure 10 shows a perspective view of the display device 400A, and Figure 11A shows a cross-sectional view of the display device 400A.

[0222] The display device 400A has a configuration in which substrate 452 and substrate 451 are bonded together. In Figure 10, substrate 452 is clearly indicated by a dashed line.

[0223] The display device 400A includes a display unit 462, a circuit 464, wiring 465, etc. Figure 10 shows an example in which IC 473 and FPC 472 are mounted on the display device 400A. Therefore, the configuration shown in Figure 10 can also be described as a display module having the display device 400A, an IC (integrated circuit), and an FPC.

[0224] For example, a scan line drive circuit can be used as circuit 464.

[0225] Wiring 465 has the function of supplying signals and power to the display unit 462 and the circuit 464. These signals and power are input to wiring 465 from an external source via FPC 472 or from IC 473.

[0226] Figure 10 shows an example in which IC 473 is mounted on the substrate 451 using a COG (Chip On Glass) method or COF (Chip On Film) method. IC 473 can be an IC having, for example, a scan line drive circuit or a signal line drive circuit. Note that the display device 400A 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.

[0227] Figure 11A shows an example of a cross-section obtained by cutting a portion of the display device 400A, including the FPC 472, a portion of the circuit 464, a portion of the display unit 462, and a portion of the area including the end.

[0228] The display device 400A shown in Figure 11A has a transistor 201, a transistor 205, a light-emitting element 430a that emits red light, a light-emitting element 430b that emits green light, and a light-emitting element 430c that emits blue light, etc., between substrates 451 and 452.

[0229] The light-emitting elements 430a, 430b, and 430c can be the light-emitting elements exemplified in Embodiment 1.

[0230] Here, if the pixels of the display device have three types of subpixels that have light-emitting elements that emit different colors from each other, examples of such three subpixels include subpixels of three colors: red (R), green (G), and blue (B); and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). If there are four such subpixels, examples of such four subpixels include subpixels of four colors: red (R), green (G), blue (B), and white (W); and subpixels of four colors: R, G, B, and Y.

[0231] The protective layer 410 and the substrate 452 are bonded together via an adhesive layer 442. For sealing the light-emitting element, a solid sealing structure or a hollow sealing structure can be applied. In Figure 11A, the space 443 surrounded by the substrate 452, the adhesive layer 442, and the substrate 451 is filled with an inert gas (such as nitrogen or argon), demonstrating the application of a hollow sealing structure. The adhesive layer 442 may be provided overlapping the light-emitting element. Alternatively, the space 443 surrounded by the substrate 452, the adhesive layer 442, and the substrate 451 may be filled with a resin different from that of the adhesive layer 442.

[0232] In an opening provided in the insulating layer 214 such that the upper surface of the conductive layer 222b of transistor 205 is exposed, parts of conductive layers 418a, 418b, and 418c are formed along the bottom and side surfaces of the opening. Conductive layers 418a, 418b, and 418c are each connected to the conductive layer 222b of transistor 205 through the opening provided in the insulating layer 214. The pixel electrode contains a material that reflects visible light, and the counter electrode contains a material that transmits visible light. In addition, other parts of conductive layers 418a, 418b, and 418c are provided on the insulating layer 214.

[0233] Pixel electrodes 411a, 411b, and 411c are provided on conductive layers 418a, 418b, and 418c, respectively. In addition, insulating layers 414 may be provided between conductive layers 418a and 411a of the light-emitting element 430a, between conductive layers 418b and 411b of the light-emitting element 430b, and between conductive layers 418c and 411c of the light-emitting element 430c.

[0234] Furthermore, as shown in Figure 11A, insulating layers 421 may be provided between the EL layer 416a of the light-emitting element 430a, the EL layer 416b of the light-emitting element 430b, and the EL layer 416c of the light-emitting element 430c.

[0235] The pixel electrodes 111 shown in the previous embodiment can be used as pixel electrodes 411a, 411b, and 411c.

[0236] An insulating layer 421 is provided in the region between the light-emitting element 430a and the light-emitting element 430b, which is on the insulating layer 214, and in the region between the light-emitting element 430b and the light-emitting element 430c, which is on the insulating layer 214. As the insulating layer 421, the insulating layer 131 shown in the previous embodiment can be used as a reference.

[0237] The light emitted by the light-emitting element is directed towards the substrate 452. It is preferable to use a material with high transmittance to visible light for the substrate 452.

[0238] Both transistors 201 and 205 are formed on the substrate 451. These transistors can be manufactured using the same materials and processes.

[0239] On the substrate 451, 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.

[0240] It is preferable to use a material that does not easily allow impurities such as water and hydrogen to diffuse into at least one layer of the insulating layer covering the transistor. This allows the insulating layer to function as a barrier layer. With such a configuration, the diffusion of impurities from the outside into the transistor can be effectively suppressed, thereby improving the reliability of the display device.

[0241] 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.

[0242] 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 400A. This prevents impurities from entering through the organic insulating film from the edge of the display device 400A. Alternatively, the organic insulating film may be formed so that its edge is inward from the edge of the display device 400A, so that the organic insulating film is not exposed at the edge of the display device 400A.

[0243] 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.

[0244] In the region 228 shown in Figure 11A, an opening is formed in the two-layer laminated structure of the insulating layer 214 and the insulating layer 421b on the insulating layer 214. The insulating layer 421b can be formed using the same material as the insulating layer 421. Also, the insulating layer 421b is formed using, for example, the same process as the insulating layer 421. A protective layer 410 is formed to cover the opening. By using an inorganic layer as the protective layer 410, even when an organic insulating film is used for the insulating layer 214, it is possible to suppress the intrusion of impurities into the display unit 462 from the outside through the insulating layer 214. Therefore, the reliability of the display device 400A can be improved.

[0245] 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, a conductive layer 222a that functions as one of the source and drain, a conductive layer 222b that functions as the other of the 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.

[0246] 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.

[0247] 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.

[0248] 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.

[0249] 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.).

[0250] 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.

[0251] 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.

[0252] 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.

[0253] For example, when describing a composition with an atomic ratio of In:Ga:Zn = 4:2:3 or a similar ratio, it includes cases where, when the atomic ratio of In is 4, the atomic ratio of Ga is between 1 and 3, and the atomic ratio of Zn is between 2 and 4. Also, when describing a composition with an atomic ratio of In:Ga:Zn = 5:1:6 or a similar ratio, it includes cases where, when the atomic ratio of In is 5, the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is between 5 and 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn = 1:1:1 or a similar ratio, it includes cases where, when the atomic ratio of In is 1, 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.

[0254] The transistors in circuit 464 and the transistors in display unit 462 may have the same structure or different structures. The structures of the multiple transistors in circuit 464 may all be the same or there may be two or more different structures. Similarly, the structures of the multiple transistors in display unit 462 may all be the same or there may be two or more different structures.

[0255] In the area of the substrate 451 where the substrate 452 does not overlap, a connection portion 204 is provided. In the connection portion 204, the wiring 465 is electrically connected to the FPC 472 via the conductive layer 466 and the connection layer 242. As the conductive layer 466, a conductive film obtained by processing the same conductive film as the pixel electrode, or a conductive film obtained by processing a laminated film of the same conductive film as the pixel electrode and the same conductive film as the optical adjustment layer can be used. On the upper surface of the connection portion 204, the conductive layer 466 is exposed. Thereby, the connection portion 204 and the FPC 472 can be electrically connected via the connection layer 242.

[0256] It is preferable to provide a light-shielding layer 417 on the surface of the substrate 452 on the side of the substrate 451. In addition, various optical members can be arranged outside the substrate 452. Examples of the optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an antireflection layer, and a condensing film. Further, outside the substrate 452, an antistatic film for suppressing the adhesion of dust, a water-repellent film for making it difficult for dirt to adhere, a hard coat film for suppressing the generation of scratches during use, a shock absorption layer, etc. may be arranged.

[0257] By providing a protective layer 410 that covers the light-emitting element, it is possible to suppress the entry of impurities such as water into the light-emitting element and improve the reliability of the light-emitting element.

[0258] In the region 228 near the end of the display device 400A, it is preferable that the insulating layer 215 and the protective layer 410 are in contact with each other through the opening of the insulating layer 214. In particular, it is preferable that the inorganic insulating film of the insulating layer 215 and the inorganic insulating film of the protective layer 410 are in contact with each other. Thereby, it is possible to suppress the entry of impurities from the outside into the display portion 462 through the organic insulating film. Therefore, the reliability of the display device 400A can be improved.

[0259] Substrates 451 and 452 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 element should be made of a material that transmits the light. Using flexible materials for substrates 451 and 452 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used as substrate 451 or substrate 452.

[0260] Substrates 451 and 452 can be made from polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. One or both of substrates 451 and 452 may be made of glass of a thickness sufficient to provide flexibility.

[0261] 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).

[0262] 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.

[0263] 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.

[0264] 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.

[0265] Various types of curing adhesives can be used as the adhesive layer, including 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.

[0266] As the connecting layer 242, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), etc., can be used.

[0267] 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.

[0268] 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 for conductive layers of various wirings and electrodes that constitute a display device, and for conductive layers of light-emitting elements (conductive layers that function as pixel electrodes or common electrodes).

[0269] 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.

[0270] Transistors 201 and 205 each have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer having a channel forming region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel forming region 231i. The insulating layer 225 is located between the conductive layer 223 and the channel forming region 231i.

[0271] Conductive layer 222a and conductive layer 222b are connected to the low-resistance region 231n via openings provided in insulating layer 215 and insulating layer 225, respectively. Of the conductive layer 222a and conductive layer 222b, one functions as a source and the other as a drain.

[0272] Figure 11B shows an example in which the insulating layer 225 covers the top and sides of the semiconductor layer. The conductive layer 222a and conductive layer 222b are connected to the low-resistance region 231n through openings provided in the insulating layer 225 and insulating layer 215, respectively.

[0273] On the other hand, in the transistor 209 shown in Figure 11C, the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231, but does not overlap with the low-resistance region 231n. For example, the structure shown in Figure 11C can be fabricated by processing the insulating layer 225 using the conductive layer 223 as a mask. In Figure 11C, an insulating layer 215 is provided covering the insulating layer 225 and the conductive layer 223, and the conductive layers 222a and 222b are connected to the low-resistance region 231n, respectively, through openings in the insulating layer 215. Furthermore, an insulating layer 218 covering the transistor may also be provided.

[0274] Furthermore, all transistors included in the pixel circuit that drives the light-emitting element may be transistors in which the semiconductor layer in which the channel is formed is silicon. Examples of silicon include single-crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, transistors having low-temperature polysilicon (LTPS (Low Temperature Poly Silicon)) in the semiconductor layer (hereinafter also referred to as LTPS transistors) can be used. LTPS transistors have high field-effect mobility and good frequency characteristics.

[0275] By using silicon-based transistors such as LTPS transistors, circuits that need to be driven at high frequencies (e.g., source driver circuits) can be fabricated on the same board as the display unit. This simplifies the external circuits implemented in the display device, reducing component and mounting costs.

[0276] Furthermore, it is preferable to use a transistor (hereinafter also called an OS transistor) in which a metal oxide (hereinafter also called an oxide semiconductor) is used as the semiconductor in which the channel is formed. OS transistors have extremely high field-effect mobility compared to amorphous silicon. In addition, OS transistors have a remarkably small source-drain leakage current (hereinafter also called an off-current) in the off state, and can retain the charge stored in a capacitor connected in series with the transistor for a long period of time. Moreover, by applying OS transistors, the power consumption of the display device can be reduced.

[0277] By using LTPS transistors in some of the transistors included in the pixel circuit and OS transistors in others, a display device with low power consumption and high driving capability can be realized. Furthermore, a configuration combining LTPS transistors and OS transistors is sometimes referred to as LTPO. In a more preferable example, it is preferable to apply OS transistors to transistors that function as switches to control conduction and non-conduction between wiring, and LTPS transistors to transistors that control current.

[0278] For example, one of the transistors provided in the pixel circuit functions as a transistor for controlling the current flowing to the light-emitting element, and can also be called a driving transistor. One of the source and drain of the driving transistor is electrically connected to the pixel electrode of the light-emitting element. It is preferable to use an LTPS transistor for this driving transistor. This makes it possible to increase the current flowing to the light-emitting element in the pixel circuit.

[0279] On the other hand, another one of the transistors provided in the pixel circuit functions as a switch for controlling selection and non-selection of the pixel, and can also be called a selection transistor. The gate of the selection transistor is electrically connected to the gate line, and one of the source and the drain is electrically connected to the source line (signal line). It is preferable to apply an OS transistor to the selection transistor. Thereby, even if the frame frequency is significantly reduced (for example, to 1 fps or less), the gradation of the pixel can be maintained. Therefore, by stopping the driver when displaying a still image, the power consumption can be reduced.

[0280] Thus, one aspect of the present invention can realize a display device having a high aperture ratio, high definition, high display quality, and low power consumption.

[0281] The configuration examples illustrated in the present embodiment, and the corresponding drawings, etc. can be appropriately combined with at least a part of other configuration examples, drawings, etc.

[0282] (Embodiment 3) In the present embodiment, a configuration example of a display device different from the above will be described.

[0283] The display device of the present embodiment can be a high-definition display device. Therefore, the display device of the present embodiment can be used, for example, for the display unit of information terminals (wearable devices) such as wristwatch type and bracelet type, as well as VR devices such as head-mounted displays, and wearable devices that can be worn on the head such as glasses-type AR devices.

[0284] [Display module] FIG. 12A shows a perspective view of the display module 280. The display module 280 includes a display device 400C and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 400C, and may be the display device 400D, the display device 400E, or the display device 400F described later.

[0285] The display module 280 has substrates 291 and 292. The display module 280 has a display unit 281. The display unit 281 is an area in the display module 280 that displays an image, and is an area in which light from each pixel provided in the pixel unit 284, which will be described later, can be seen.

[0286] Figure 12B shows a schematic perspective view illustrating the configuration of the substrate 291. On the substrate 291, a circuit section 282, a pixel circuit section 283 on the circuit section 282, and a pixel section 284 on the pixel circuit section 283 are stacked. In addition, a terminal section 285 for connecting to the FPC 290 is provided in the portion of the substrate 291 that does not overlap with the pixel section 284. The terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286, which is composed of multiple wires.

[0287] The pixel section 284 has a plurality of pixels 284a arranged periodically. A magnified view of one pixel 284a is shown on the right side of Figure 12B. The pixel 284a has light-emitting elements 430a, 430b, and 430c that emit light in different colors from each other. It is preferable to arrange the plurality of light-emitting elements in a stripe arrangement as shown in Figure 12B. By using a stripe arrangement, the light-emitting elements of one aspect of the present invention can be arranged in a high-density pixel circuit, thereby providing a high-definition display device. Furthermore, various arrangement methods such as delta arrangement and pentile arrangement can be applied.

[0288] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0289] A single pixel circuit 283a is a circuit that controls the light emission of the three light-emitting elements of a single pixel 284a. A single pixel circuit 283a may be configured to have three circuits that control the light emission of a single light-emitting element. For example, a single pixel circuit 283a 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.

[0290] The circuit section 282 has circuits for driving each pixel circuit 283a of the pixel circuit section 283. For example, it is preferable to have one or both of a gate line drive circuit and a source line drive circuit. In addition, it may have at least one of the following: an arithmetic circuit, a memory circuit, and a power supply circuit.

[0291] The FPC290 functions as wiring for supplying video signals or power potential, etc., to the circuit section 282 from an external source. An IC may also be mounted on the FPC290.

[0292] The display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are stacked on the lower side of the pixel section 284, thereby enabling an extremely high aperture ratio (effective display area ratio) of the display section 281. For example, the aperture ratio of the display section 281 can be 40% or more and less than 100%, preferably 50% or more and 95%, and more preferably 60% or more and 95%. Furthermore, it is possible to arrange the pixels 284a at an extremely high density, enabling an extremely high resolution of the display section 281. For example, it is preferable that the pixels 284a in the display section 281 are arranged with a resolution of 20000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and with a resolution of 20000 ppi or less, or 30000 ppi or less.

[0293] Because such a display module 280 is extremely high-resolution, it can be suitably used in VR devices such as head-mounted displays, or in glasses-type AR devices. For example, even in a configuration where the display part of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display part 281, so even when the display part is magnified with lenses, pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 280 is not limited to this, and can be suitably used in electronic devices with relatively small display parts. For example, it can be suitably used in the display part of wearable electronic devices such as wristwatches.

[0294] [Display device 400C] The display device 400C shown in Figure 13 comprises a substrate 301, light-emitting elements 430a, 430b, and 430c, a capacitor 240, and a transistor 310.

[0295] The transistor 310 is a transistor having a channel-forming region in the substrate 301. The substrate 301 can be a semiconductor substrate such as a single-crystal silicon substrate. The transistor 310 comprises a portion of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region of the substrate 301 doped with impurities and functions as either a source or a drain. The insulating layer 314 covers the side surface of the conductive layer 311 and functions as an insulating layer.

[0296] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0297] Furthermore, an insulating layer 261 is provided covering the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0298] Capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located between them. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as the dielectric of the capacitor 240.

[0299] The conductive layer 241 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is electrically connected to either the source or drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided covering the conductive layer 241. The conductive layer 245 is provided in the region that overlaps with the conductive layer 241 via the insulating layer 243.

[0300] An insulating layer 255 is provided covering the capacitance 240, and light-emitting elements 430a, 430b, 430c, etc. are provided on the insulating layer 255. A protective layer 416 is provided on the light-emitting elements 430a, 430b, 430c, and a substrate 420 is bonded to the upper surface of the protective layer 416 by a resin layer 419. The substrate 420 corresponds to the substrate 292 in Figure 12A.

[0301] The pixel electrodes of the light-emitting element are electrically connected to either the source or drain of the transistor 310 by plugs 256 embedded in the insulating layer 255, a conductive layer 241 embedded in the insulating layer 254, and plugs 271 embedded in the insulating layer 261.

[0302] [Display device 400D] The display device 400D shown in Figure 14 differs from the display device 400C mainly in its transistor configuration. Note that explanations of parts similar to those of the display device 400C may be omitted.

[0303] Transistor 320 is a transistor in which a metal oxide (also called an oxide semiconductor) is applied to the semiconductor layer where the channel is formed.

[0304] The transistor 320 has a semiconductor layer 321, an insulating layer 323, a conductive layer 324, a pair of conductive layers 325, an insulating layer 326, and a conductive layer 327.

[0305] Substrate 331 corresponds to substrate 291 in Figures 12A and 12B. An insulating substrate or a semiconductor substrate can be used as substrate 331.

[0306] An insulating layer 332 is provided on the substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320, and prevents oxygen from detaching from the semiconductor layer 321 to the insulating layer 332. As the insulating layer 332, for example, a film that is less susceptible to hydrogen or oxygen diffusion than a silicon oxide film can be used, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0307] A conductive layer 327 is provided on an insulating layer 332, and an insulating layer 326 is provided covering the conductive layer 327. The conductive layer 327 functions as the first gate electrode of the transistor 320, and a portion of the insulating layer 326 functions as the first gate insulating layer. It is preferable to use an oxide insulating film, such as a silicon oxide film, for at least the portion of the insulating layer 326 that is in contact with the semiconductor layer 321. It is preferable that the upper surface of the insulating layer 326 is flattened.

[0308] The semiconductor layer 321 is provided on the insulating layer 326. Preferably, the semiconductor layer 321 has a metal oxide (also called an oxide semiconductor) film having semiconductor properties. Details of materials suitable for use in the semiconductor layer 321 will be described later.

[0309] A pair of conductive layers 325 are provided in contact with the semiconductor layer 321 and function as source and drain electrodes.

[0310] Furthermore, an insulating layer 328 is provided covering the top and side surfaces of the pair of conductive layers 325, as well as the side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided on the insulating layer 328. The insulating layer 328 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing into the semiconductor layer 321 from the insulating layer 264, etc., and to prevent oxygen from detaching from the semiconductor layer 321. As the insulating layer 328, an insulating film similar to that of the insulating layer 332 can be used.

[0311] An opening is provided in the insulating layer 328 and the insulating layer 264 that reaches the semiconductor layer 321. Inside this opening, the insulating layer 323 and the conductive layer 324 are embedded, in contact with the sides of the insulating layer 264, the insulating layer 328, and the conductive layer 325, as well as the upper surface of the semiconductor layer 321. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0312] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are flattened so that their heights are roughly the same, and the insulating layer 329 and insulating layer 265 are provided covering them.

[0313] Insulating layers 264 and 265 function as interlayer insulating layers. Insulating layer 329 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing into the transistor 320 from insulating layer 265, etc. As insulating layer 329, an insulating film similar to that used for insulating layers 328 and 332 can be used.

[0314] A plug 274, which is electrically connected to one of the pair of conductive layers 325, is provided so as to be embedded in the insulating layers 265, 329, and 264. Here, it is preferable that the plug 274 has a conductive layer 274a that covers the sides of the openings of the insulating layers 265, 329, 264, and 328, and a part of the upper surface of the conductive layer 325, and a conductive layer 274b that is in contact with the upper surface of the conductive layer 274a. In this case, it is preferable to use a conductive material that does not easily allow hydrogen and oxygen to diffuse as the conductive layer 274a.

[0315] The configuration from the insulating layer 254 to the substrate 420 in the display device 400D is the same as that of the display device 400C.

[0316] [Display device 400E] The display device 400E shown in Figure 15 has a configuration in which transistors 310A and 310B, each with a channel formed on a semiconductor substrate, are stacked.

[0317] The display device 400E has a configuration in which a substrate 301B on which transistors 310B, capacitors 240, and each light-emitting device are provided, and a substrate 301A on which transistor 310A is provided are bonded together.

[0318] A plug 343 is provided on substrate 301B, which penetrates the substrate 301B. The plug 343 is electrically connected to a conductive layer 342 provided on the back surface of substrate 301B (the surface opposite to the substrate 420 side). On the other hand, a conductive layer 341 is provided on substrate 301A on an insulating layer 261.

[0319] The conductive layer 341 and the conductive layer 342 are joined together, thereby electrically connecting substrate 301A and substrate 301B.

[0320] It is preferable to use the same conductive material for conductive layer 341 and conductive layer 342. For example, a metal film containing an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, or a metal nitride film (titanium nitride film, molybdenum nitride film, tungsten nitride film) composed of the above elements can be used. In particular, it is preferable to use copper for conductive layer 341 and conductive layer 342. This allows the application of Cu-Cu (copper-copper) direct bonding technology (a technology that achieves electrical conductivity by connecting Cu (copper) pads to each other). The conductive layer 341 and conductive layer 342 may be bonded via bumps.

[0321] [Display device 400F] The display device 400F shown in Figure 16 has a configuration in which a transistor 310 with a channel formed on a substrate 301 and a transistor 320 containing a metal oxide in the semiconductor layer where the channel is formed are stacked. Note that explanations of parts that are the same as those of display devices 400C and 400D may be omitted.

[0322] An insulating layer 261 is provided covering the transistor 310, and a conductive layer 251 is provided on the insulating layer 261. An insulating layer 262 is provided covering the conductive layer 251, and a conductive layer 252 is provided on the insulating layer 262. The conductive layers 251 and 252 each function as wiring. An insulating layer 263 and an insulating layer 332 are provided covering the conductive layer 252, and a transistor 320 is provided on the insulating layer 332. An insulating layer 265 is provided covering the transistor 320, and a capacitor 240 is provided on the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0323] Transistor 320 can be used as a transistor constituting a pixel circuit. Transistor 310 can also be used as a transistor constituting a pixel circuit, or as a transistor constituting a drive circuit (gate line drive circuit, source line drive circuit) for driving the pixel circuit. Furthermore, transistors 310 and 320 can be used as transistors constituting various circuits such as arithmetic circuits or memory circuits.

[0324] This configuration allows for the formation of not only pixel circuits but also drive circuits and other components directly beneath the light-emitting element, making it possible to miniaturize the display device compared to cases where the drive circuits are located around the display area.

[0325] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part.

[0326] (Embodiment 4) In this embodiment, a light-emitting element (also called a light-emitting device) that can be used in a display device according to one aspect of the present invention will be described.

[0327] <Example of light-emitting device configuration> As shown in Figure 17A, the light-emitting device has an EL layer 786 between a pair of electrodes (lower electrode 772, upper electrode 788). The EL layer 786 can be composed of multiple layers, such as layer 4420, light-emitting layer 4411, and layer 4430. Layer 4420 may include, for example, a layer containing a material with high electron injection properties (electron injection layer) and a layer containing a material with high electron transport properties (electron transport layer). Light-emitting layer 4411 may include, for example, a light-emitting compound. Layer 4430 may include, for example, a layer containing a material with high hole injection properties (hole injection layer) and a layer containing a material with high hole transport properties (hole transport layer).

[0328] A configuration having a layer 4420, an emissive layer 4411, and a layer 4430 provided between a pair of electrodes can function as a single emissive unit, and in this specification, the configuration shown in Figure 17A is referred to as a single structure.

[0329] Furthermore, Figure 17B shows a modified example of the EL layer 786 of the light-emitting device shown in Figure 17A. Specifically, the light-emitting device shown in Figure 17B has a layer 4430-1 on the lower electrode 772, a layer 4430-2 on layer 4430-1, a light-emitting layer 4411 on layer 4430-2, a layer 4420-1 on the light-emitting layer 4411, a layer 4420-2 on layer 4420-1, and an upper electrode 788 on layer 4420-2. For example, when the lower electrode 772 is the anode and the upper electrode 788 is the cathode, layer 4430-1 functions as a hole injection layer, layer 4430-2 functions as a hole transport layer, layer 4420-1 functions as an electron transport layer, and layer 4420-2 functions as an electron injection layer. Alternatively, when the lower electrode 772 is used as the cathode and the upper electrode 788 is used as the anode, layer 4430-1 functions as an electron injection layer, layer 4430-2 functions as an electron transport layer, layer 4420-1 functions as a hole transport layer, and layer 4420-2 functions as a hole injection layer. By using such a layer structure, it is possible to efficiently inject carriers into the light-emitting layer 4411 and increase the efficiency of carrier recombination within the light-emitting layer 4411.

[0330] Furthermore, as shown in Figures 17C and 17D, a configuration in which multiple light-emitting layers (light-emitting layers 4411, 4412, and 4413) are provided between layer 4420 and layer 4430 is also a variation of the single structure.

[0331] Furthermore, as shown in Figures 17E and 17F, a configuration in which multiple light-emitting units (EL layer 786a, EL layer 786b) are connected in series via an intermediate layer (charge generation layer) 4440 is referred to as a tandem structure in this specification. In this specification, the configuration shown in Figures 17E and 17F is referred to as a tandem structure, but it is not limited to this, and for example, a tandem structure may also be called a stack structure. By using a tandem structure, a light-emitting device capable of high-brightness light emission can be made.

[0332] In Figure 17C, the light-emitting layers 4411, 4412, and 4413 may be made of light-emitting materials that emit light of the same color.

[0333] Furthermore, different light-emitting materials may be used for the light-emitting layers 4411, 4412, and 4413. When the light emitted by the light-emitting layers 4411, 4412, and 4413 are complementary in color, white light emission is obtained. Figure 17D shows an example in which a colored layer 785, which functions as a color filter, is provided. By passing white light through the color filter, light of the desired color can be obtained.

[0334] Furthermore, in Figure 17E, the same light-emitting material may be used for both the light-emitting layer 4411 and the light-emitting layer 4412. Alternatively, light-emitting materials emitting different colors of light may be used for both the light-emitting layer 4411 and the light-emitting layer 4412. When the light emitted by the light-emitting layer 4411 and the light emitted by the light-emitting layer 4412 are complementary colors, white light emission is obtained. Figure 17F shows an example in which a colored layer 785 is further provided.

[0335] Furthermore, in Figures 17C, 17D, 17E, and 17F, as shown in Figure 17B, layer 4420 and layer 4430 may be a laminated structure consisting of two or more layers.

[0336] A structure in which different light-emitting layers (in this case, blue (B), green (G), and red (R)) are created for each light-emitting device is sometimes called an SBS (Side By Side) structure.

[0337] The light-emitting color of the light-emitting device can be red, green, blue, cyan, magenta, yellow, or white, depending on the material that makes up the EL layer 786. Furthermore, the color purity can be further enhanced by adding a microcavity structure to the light-emitting device.

[0338] A light-emitting device that emits white light preferably has a configuration that includes two or more types of light-emitting materials in its light-emitting layer. To obtain white light emission, it is sufficient to select light-emitting materials such that the light emitted by each of the two or more materials is complementary in color. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary, a light-emitting device that emits white light as a whole can be obtained. The same applies to light-emitting devices that have three or more light-emitting layers.

[0339] The light-emitting layer preferably contains two or more light-emitting materials that emit light such as R (red), G (green), B (blue), Y (yellow), and O (orange). Alternatively, it is preferable to have two or more light-emitting materials, and for each light-emitting material to emit light that contains spectral components of two or more colors from R, G, and B.

[0340] Here, we will describe a specific example of the configuration of a light-emitting device.

[0341] The light-emitting device has at least a light-emitting layer. The light-emitting device may also have layers other than the light-emitting layer that include 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, an electron-blocking material, a material with high electron injection properties, or a bipolar material (a material with high electron transport and hole transport properties).

[0342] 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.

[0343] For example, a light-emitting device can have a configuration that includes, in addition to the light-emitting layer, one or more layers from among 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.

[0344] 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).

[0345] 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. As for the hole-transporting material, 10 -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.

[0346] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light-emitting layer. The electron transport layer is a layer containing an electron-transporting material. The electron-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having an electron mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes. Examples of electron-transporting materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds.

[0347] 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.

[0348] 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.

[0349] Alternatively, an electron-transporting material may be used as the electron injection layer described above. 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.

[0350] 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.

[0351] 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. NBPhen has a higher glass transition temperature (Tg) and superior heat resistance compared to BPhen.

[0352] 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.

[0353] Examples of luminescent materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0354] 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.

[0355] 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.

[0356] 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.

[0357] 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.

[0358] This embodiment can be combined with other embodiments as appropriate.

[0359] (Embodiment 5) This embodiment describes metal oxides (also called oxide semiconductors) that can be used in the OS transistor described in the above embodiment.

[0360] The metal oxide preferably contains at least indium or zinc. It is particularly preferable that it contains indium and zinc. In addition, it is preferable that it contains aluminum, gallium, yttrium, tin, etc. It may also contain one or more selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, etc.

[0361] 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).

[0362] <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.

[0363] 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.

[0364] 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.

[0365] 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.

[0366] <<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.

[0367] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0368] [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.

[0369] 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.

[0370] 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.

[0371] 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.

[0372] 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.

[0373] 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.

[0374] 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.

[0375] 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 or 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.

[0376] [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 and 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.

[0377] [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.

[0378] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0379] [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.

[0380] 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.

[0381] 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.

[0382] 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.

[0383] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

[0384] 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.

[0385] 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.

[0386] 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.

[0387] 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.

[0388] 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.

[0389] Therefore, when using CAC-OS in a transistor, the conductivity caused by the first region and the insulation caused by the second region act complementarily, enabling the function of switching (on / off function) to be imparted to the CAC-OS. That is, CAC-OS has a conductive function in a part of the material and an insulating function in a part of the material, and has a semiconductor function as a whole. By separating the conductive function and the insulating function, both functions can be enhanced to the maximum extent. 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 realized.

[0390] In addition, a transistor using CAC-OS has high reliability. Therefore, CAC-OS is optimal for various semiconductor devices including display devices.

[0391] Oxide semiconductors have various structures and each has different characteristics. The oxide semiconductor of one aspect of the present invention may have two or more of amorphous oxide semiconductor, polycrystalline oxide semiconductor, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0392] <Transistor having an oxide semiconductor> Subsequently, the case of using the above oxide semiconductor in a transistor will be described.

[0393] By using the above oxide semiconductor in a transistor, a transistor with high field-effect mobility can be realized. Also, a highly reliable transistor can be realized.

[0394] It is preferable to use an oxide semiconductor with a low carrier concentration in a transistor. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 or less, preferably 1×10 15 cm -3 or less, 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.

[0395] 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.

[0396] 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.

[0397] 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.

[0398] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0399] 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 concentrations of silicon and carbon in the oxide semiconductor and the concentrations of silicon and carbon near the interface with the oxide semiconductor (concentrations 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:

[0400] 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:

[0401] 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:

[0402] 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.

[0403] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be provided.

[0404] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0405] (Embodiment 6) In this embodiment, an electronic device according to one aspect of the present invention will be described with reference to Figures 18A to 21F.

[0406] The electronic device of this embodiment has a display device according to one aspect of the present invention. The display device according to one aspect of the present invention is easily made high-definition, high-resolution, and large-scale. Therefore, the display device according to one aspect of the present invention can be used in the display units of various electronic devices.

[0407] Furthermore, since the display device according to one aspect of the present invention can be manufactured at a low cost, the manufacturing cost of electronic devices can be reduced.

[0408] 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.

[0409] 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 resolution. Examples of such electronic devices include information terminals (wearable devices) such as wristwatches and bracelets, as well as wearable devices that can be worn on the head, such as VR devices such as head-mounted displays and AR devices such as glasses. Wearable devices also include devices for SR and MR.

[0410] 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), 4K2K (3840 x 2160 pixels), or 8K4K (7680 x 4320 pixels). In particular, a resolution of 4K2K, 8K4K, or higher is preferred. Furthermore, the pixel density (resolution) of the display device according to one aspect of the present invention is 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 display devices with such high resolution or detail, it becomes possible to enhance the sense of presence and depth in personal electronic devices such as portable or home-use devices.

[0411] The electronic device of this embodiment can be incorporated along the curved surfaces of the interior or exterior walls of a house or building, or the interior or exterior of an automobile.

[0412] The electronic device in this embodiment may have an antenna. By receiving signals with the antenna, the display unit can display images and information. Furthermore, if the electronic device has an antenna and a secondary battery, the antenna may be used for contactless power transmission.

[0413] 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).

[0414] 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.

[0415] The electronic device 6500 shown in Figure 18A is a portable information terminal that can be used as a smartphone.

[0416] 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.

[0417] A display device according to one aspect of the present invention can be applied to the display unit 6502.

[0418] Figure 18B is a schematic cross-sectional view of the housing 6501, including the end on the microphone 6506 side.

[0419] 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.

[0420] 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).

[0421] 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.

[0422] A flexible display (a display device with flexibility) according to one embodiment of the present invention can be applied to the display panel 6511. As a result, an extremely lightweight electronic device can be realized. Furthermore, because the display panel 6511 is extremely thin, a large-capacity battery 6518 can be installed 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, an electronic device with a narrow bezel can be realized.

[0423] Figure 19A 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.

[0424] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0425] The television device 7100 shown in Figure 19A 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.

[0426] 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.

[0427] Figure 19B 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.

[0428] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0429] Figures 19C and 19D show examples of digital signage.

[0430] The digital signage 7300 shown in Figure 19C 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 switches), connection terminals, various sensors, a microphone, etc.

[0431] Figure 19D 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.

[0432] In Figures 19C and 19D, a display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0433] 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.

[0434] 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.

[0435] Furthermore, as shown in Figures 19C and 19D, 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. Also, the display on the display unit 7000 can be switched by operating the information terminal 7311 or information terminal 7411.

[0436] 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 a large number of users to participate in and enjoy the game simultaneously.

[0437] Figure 20A shows the external appearance of the camera 8000 with the viewfinder 8100 attached.

[0438] The camera 8000 includes a housing 8001, a display unit 8002, operation buttons 8003, a shutter button 8004, etc. A detachable lens 8006 is also attached to the camera 8000. The lens 8006 and the housing of the camera 8000 may be integrated into a single unit.

[0439] Camera 8000 can take an image by pressing the shutter button 8004 or by touching the display unit 8002, which functions as a touch panel.

[0440] The housing 8001 has a mount with electrodes, and in addition to the viewfinder 8100, a strobe device and the like can be connected to it.

[0441] The viewfinder 8100 includes a housing 8101, a display unit 8102, buttons 8103, etc.

[0442] The housing 8101 is attached to the camera 8000 by a mount that engages with the camera 8000's mount. The viewfinder 8100 can display images and other data received from the camera 8000 on the display unit 8102.

[0443] Button 8103 functions as a power button, etc.

[0444] A display device according to one embodiment of the present invention can be applied to the display unit 8002 of the camera 8000 and the display unit 8102 of the viewfinder 8100. The camera 8000 may also have a built-in viewfinder.

[0445] Figure 20B shows the external appearance of the head-mounted display 8200.

[0446] The head-mounted display 8200 includes a mounting section 8201, lenses 8202, a main unit 8203, a display unit 8204, a cable 8205, etc. The mounting section 8201 also has a built-in battery 8206.

[0447] Cable 8205 supplies power from battery 8206 to main unit 8203. Main unit 8203 is equipped with a wireless receiver and can display received video information on display unit 8204. In addition, main unit 8203 is equipped with a camera and can use information about the user's eyeball or eyelid movements as an input means.

[0448] Furthermore, the attachment unit 8201 may be provided with multiple electrodes at a position that touches the user, capable of detecting the current flowing in accordance with the user's eye movements, and may have a function to recognize the user's gaze. It may also have a function to monitor the user's pulse rate based on the current flowing through the electrodes. In addition, the attachment unit 8201 may have various sensors such as a temperature sensor, a pressure sensor, and an acceleration sensor, and may have a function to display the user's biometric information on the display unit 8204, or a function to change the image displayed on the display unit 8204 in accordance with the user's head movements.

[0449] A display device according to one aspect of the present invention can be applied to the display unit 8204.

[0450] Figures 20C to 20E show the external appearance of the head-mounted display 8300. The head-mounted display 8300 includes a housing 8301, a display unit 8302, a band-shaped fixing device 8304, and a pair of lenses 8305.

[0451] The user can view the display on the display unit 8302 through the lens 8305. It is preferable to position the display unit 8302 in a curved shape, as this allows the user to experience a greater sense of presence. Furthermore, by viewing different images displayed in different areas of the display unit 8302 through the lens 8305, three-dimensional display using parallax can be performed. Note that the configuration is not limited to a single display unit 8302; two display units 8302 may be provided, with one display unit for each of the user's eyes.

[0452] A display device according to one embodiment of the present invention can be applied to the display unit 8302. This display device according to one embodiment of the present invention can achieve extremely high resolution. For example, even when the display is magnified and viewed using the lens 8305 as shown in Figure 20E, the pixels are difficult for the user to see. In other words, the display unit 8302 can be used to allow the user to view highly realistic images.

[0453] Figure 20F shows the external appearance of a goggle-type head-mounted display 8400. The head-mounted display 8400 has a pair of housings 8401, a mounting part 8402, and a cushioning member 8403. A display unit 8404 and a lens 8405 are provided inside each of the pair of housings 8401. By displaying different images on the pair of display units 8404, a three-dimensional display using parallax can be achieved.

[0454] The user can view the display unit 8404 through the lens 8405. The lens 8405 has a focus adjustment mechanism and its position can be adjusted according to the user's eyesight. The display unit 8404 is preferably a square or a horizontally elongated rectangle. This can enhance the sense of realism.

[0455] The mounting portion 8402 is preferably adjustable to the size of the user's face and has plasticity and elasticity to prevent it from slipping off. Furthermore, it is preferable that a part of the mounting portion 8402 has a vibration mechanism that functions as a bone conduction earphone. This eliminates the need for separate audio equipment such as earphones or speakers, allowing users to enjoy video and audio simply by wearing the device. The housing 8401 may also have a function to output audio data via wireless communication.

[0456] The mounting portion 8402 and the cushioning member 8403 are parts that come into contact with the user's face (forehead, cheeks, etc.). By ensuring that the cushioning member 8403 is in close contact with the user's face, light leakage can be prevented, thereby enhancing the sense of immersion. It is preferable to use a soft material for the cushioning member 8403 so that it adheres closely to the user's face when the user wears the head-mounted display 8400. For example, materials such as rubber, silicone rubber, urethane, and sponge can be used. Furthermore, if the surface of a sponge or similar material is covered with cloth, leather (genuine leather or synthetic leather), gaps are less likely to form between the user's face and the cushioning member 8403, effectively preventing light leakage. In addition, using such materials is preferable because it feels good against the skin and does not make the user feel cold when worn in cold seasons. It is preferable that the components that come into contact with the user's skin, such as the cushioning member 8403 or the mounting portion 8402, are removable, as this makes cleaning or replacement easier.

[0457] The electronic equipment shown in Figures 21A to 21F 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.

[0458] The electronic devices shown in Figures 21A to 21F 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.

[0459] A display device according to one embodiment of the present invention can be applied to the display unit 9001.

[0460] Details of the electronic equipment shown in Figures 21A to 21F will be explained below.

[0461] Figure 21A 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 21A 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 or phone calls, the subject of emails or SNS, sender name, date and time, battery level, and antenna signal strength. Alternatively, icons 9050 or the like may be displayed in the location where the information 9051 is displayed.

[0462] Figure 21B 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.

[0463] Figure 21C 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 be used for 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.

[0464] Figures 21D to 21F are perspective views showing a foldable portable information terminal 9201. Figure 21D shows the portable information terminal 9201 in an unfolded state, Figure 21F shows it in a folded state, and Figure 21E shows a perspective view of the state in between Figures 21D and 21F. The portable 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 portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display unit 9001 can be bent with a radius of curvature of 0.1 mm to 150 mm.

[0465] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part. [Examples]

[0466] In this embodiment, a display panel according to one aspect of the present invention was fabricated.

[0467] [Creation of display panel] The display panel was fabricated based on the method exemplified in Embodiment 1, Fabrication Method Example 1. Specifically, first, a substrate was prepared on which a pixel circuit comprising transistors and wiring, and pixel electrodes were formed on a single-crystal silicon substrate. Next, a red EL layer, a green EL layer, and a blue EL layer were formed in order, and then an insulating layer was formed to protect the sides of each EL layer. Subsequently, the sacrificial layer and protective layer on each EL layer were removed. Next, an electron injection layer, a common electrode, and a protective layer were formed in order on the EL layers.

[0468] A single-crystal silicon substrate was used as the base material, and a display panel was fabricated by sequentially stacking a single-crystal silicon transistor, a wiring layer, an oxide semiconductor transistor (OS transistor), and a light-emitting element. For the OS transistor, an In-Ga-Zn oxide film (IGZO) was used for the semiconductor layer.

[0469] The EL layer was formed with a laminated structure consisting of a hole injection layer, a hole transport layer, an emissive layer, and an electron transport layer. For the sacrificial layer, an aluminum oxide film formed by ALD at a substrate temperature of 80°C and a tungsten film formed by sputtering were used. For the insulating layer protecting the sidewalls of the EL layer, an aluminum oxide film formed by ALD and a photosensitive resin were used. For the electron injection layer, a laminated film of lithium fluoride and ytterbium was used, a mixed film of silver and magnesium was used for the common electrode, and an ITO film formed by sputtering was used as the protective layer on the common electrode.

[0470] The display panel fabricated in this embodiment has a square display area with a diagonal size of 0.99 inches, an effective pixel count of 1920 x 1920, a resolution of 2731 ppi, a pixel pitch of 9.3 μm x 9.3 μm, a pixel arrangement of R, G, B stripes, an aperture ratio of 43% (design value), and a frame frequency of 90 Hz.

[0471] [Display results] Figures 22A and 22B show photographs of the fabricated display panel. By using a color-coding method that does not employ a metal mask, it was possible to achieve an extremely high resolution of 2731 ppi and a color image.

[0472] [Spectral measurement] Spectral measurements were performed on the fabricated display panel. The measurement involved displaying all pixels of the display panel in red (R), green (G), blue (B), and black (BK), respectively, and measuring the wavelength dependence of the spectral radiant intensity. For comparison, two types of display panels (Comparative Example 1 and Comparative Example 2) using a white OLED and a color filter were also evaluated in the same manner. The resolution of Comparative Example 1 and Comparative Example 2 is comparable to that of the display panel fabricated in this example (referred to as "Example").

[0473] Figures 23A, 23B, and 23C show the spectral measurement results for Example, Comparative Example 1, and Comparative Example 2, respectively. Figures 24A, 24B, and 24C use a logarithmic scale for the vertical axis. In each figure, the horizontal axis represents wavelength [nm], and the vertical axis represents spectral radiance [W / sr / m]. 2 The value is [ / nm]. Also, the results shown in black (BK) are omitted in Figures 23A, 23B, and 23C.

[0474] Focusing on the examples, it can be seen that the full width at half maximum (FMAX) is small for R, G, and B, and there is almost no overlap in the spectra of each color. Furthermore, as shown in Figure 24A, almost no light emission was observed when displaying black, indicating that light leakage during black display is extremely small.

[0475] On the other hand, focusing on Comparative Example 1, it can be seen that the spectral full width at half maximum is larger compared to the example. Furthermore, peaks are observed around 650 nm in the blue display (B), and around 450 nm and 620 nm in the green display (G). These peaks are presumed to be due to crosstalk and are a factor in the decrease in contrast. Moreover, as shown in Figure 24B, even in the black display, slight emission is observed around 600 nm to 700 nm, confirming that light leakage is occurring.

[0476] Furthermore, in Comparative Example 2, as shown in Figure 24C, no light leakage was observed when displaying black, but in blue (B) and green (G) displays, luminescence due to crosstalk was observed around a wavelength of 600 nm.

[0477] From the above, it was confirmed that the display panel fabricated in this embodiment achieves extremely high contrast and color rendering without any crosstalk, despite having an extremely high resolution of 2731 ppi. [Explanation of symbols]

[0478] 100: Display device, 101: Substrate, 103: Pixel, 110: Light-emitting element, 110B: Light-emitting element, 110G: Light-emitting element, 110R: Light-emitting element, 111: Pixel electrode, 111B: Pixel electrode, 111C: Connection electrode, 111G: Pixel electrode, 111R: Pixel electrode, 112: EL layer, 112B: EL layer, 112Bf: EL film, 112G: EL layer, 112Gf: EL film, 112R: EL layer, 112Rf: EL film, 113: Common electrode, 114: Common layer, 121: Protective layer, 130: Region, 131: Insulating layer, 131a: Insulating layer, 131af: Insulating film, 131ap: Insulating layer, 131b: Insulating layer, 131bf: insulating film, 143a: resist mask, 143b: resist mask, 143c: resist mask, 144: sacrificial film, 144B: sacrificial film, 144G: sacrificial film, 144R: sacrificial film, 145: sacrificial layer, 145B: sacrificial layer, 145G: sacrificial layer, 145R: sacrificial layer, 201: transistor, 204: connector, 205: transistor, 209: 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, 240: Capacitance, 241: Conductive layer, 242: Connection layer, 243: Insulating layer, 245: Conductive layer, 251: Conductive layer, 252: Conductive layer, 254: Insulating layer, 255: Insulating layer, 256: Plug, 261: Insulating layer, 262: Insulating layer, 263: Insulating layer, 264: Insulating layer, 265: Insulating layer, 271: Plug, 274: Plug, 274a: Conductive layer, 274b: Conductive layer, 280: Display module, 281: Display section, 282: Circuit section, 283: Pixel circuit section, 283a: Pixel circuit, 284: Pixel section, 284a :Pixel, 285:Terminal section, 286:Wiring section, 290:FPC, 291:Substrate, 292:Substrate, 301:Substrate, 301A:Substrate, 301B:Substrate, 310:Transistor, 310A:Transistor, 310B:Transistor, 311:Conductive layer, 312:Low resistance region, 313:Insulating layer, 314:Insulating layer, 315:Element isolation layer, 320:Transistor, 321:Semiconductor layer, 323:Insulating layer, 324:Conductive layer, 325:Conductive layer, 326:Insulating layer, 327:Conductive layer, 328:Insulating layer, 329:Insulating layer, 331:Substrate, 332:Insulating layer, 341:Conductive layer, 342:Conductive layer,343: Plug, 400A: Display device, 400C: Display device, 400D: Display device, 400E: Display device, 400F: Display device, 410: Protective layer, 411a: Pixel electrode, 411b: Pixel electrode, 411c: Pixel electrode, 414: Insulating layer, 416: Protective layer, 416a: EL layer, 416b: EL layer, 416c: EL layer, 417: Light-shielding layer, 418a: Conductive layer, 418b: Conductive layer, 418c: Conductive layer, 419: Resin layer, 420: Substrate, 421: Insulating layer, 421b: Insulating layer, 430a: Light-emitting element, 430b: Light-emitting element, 430c: Light-emitting element, 442: Adhesive layer, 443: Air Interval, 451: substrate, 452: substrate, 462: display unit, 464: circuit, 465: wiring, 466: conductive layer, 472: FPC, 473: IC, 772: lower electrode, 785: colored layer, 786: EL layer, 786a: EL layer, 786b: EL layer, 788: upper electrode, 4411: light-emitting layer, 4412: light-emitting layer, 4413: light-emitting layer, 4420: layer, 4420-1: layer, 4420-2: layer, 4430: layer, 4430-1: layer, 4430-2: layer, 6500: electronic equipment, 6501: housing, 6502: display unit, 6503: power button, 6504: button, 6505: speaker, 650 6: 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 unit, 7200: Notebook personal computer, 7211: Enclosure, 7212: Keyboard, 7213: Pointing device, 7214: External connection port, 7300: Digital signage, 730 1: Housing, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 8000: Camera, 8001: Housing, 8002: Display unit, 8003: Operation buttons, 8004: Shutter button, 8006: Lens, 8100: Viewfinder, 8101: Housing, 8102: Display unit, 8103: Buttons, 8200: Head-mounted display, 8201: Mounting unit, 8202: Lens, 8203: Main unit, 8204: Display unit, 8205: Cable, 8206: Battery, 8300: Head-mounted display,8301: Housing, 8302: Display unit, 8304: Fixing device, 8305: Lens, 8400: Head-mounted display, 8401: Housing, 8402: Mounting part, 8403: Cushioning material, 8404: Display unit, 8405: Lens, 9000: Housing, 9001: Display unit, 9003: Speaker, 9005: Operation keys, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9101: Personal Information Terminal, 9102: Personal Information Terminal, 9200: Personal Information Terminal, 9201: Personal Information Terminal,

Claims

1. A display device comprising a first pixel, a second pixel arranged adjacent to the first pixel, a first insulating layer, a second insulating layer, a third insulating layer, and a fourth insulating layer, The first pixel comprises a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer. The second pixel comprises a second pixel electrode, a second EL layer on the second pixel electrode, and the common electrode on the second EL layer. The side surface of the first EL layer and the side surface of the second EL layer have a region in contact with the first insulating layer. The upper surface of the first EL layer has a region that overlaps with the first insulating layer via the third insulating layer. The upper surface of the second EL layer has a region that overlaps with the first insulating layer via the fourth insulating layer. The second insulating layer is provided in contact with the first insulating layer and is positioned below the common electrode. The first insulating layer has an inorganic material, The second insulating layer has an organic material, The third insulating layer described above has an inorganic material, The side surface of the first pixel electrode is covered by the first EL layer. The side surface of the second pixel electrode is covered by the second EL layer in the display device.

2. In claim 1, A display device having a region in contact with the common electrode on the upper surface of the first EL layer, the upper surface of the second EL layer, and the upper surface of the first insulating layer.

3. In claim 1, The first pixel has a common layer disposed between the first EL layer and the common electrode, The second pixel has the common layer disposed between the second EL layer and the common electrode, A display device having a region in contact with the common layer, where the upper surface of the first EL layer, the upper surface of the second EL layer, the side surface of the first insulating layer, the side surface of the third insulating layer, and the side surface of the fourth insulating layer are all located.

Images