Display devices, display modules, and electronic devices

Abstract

The present invention provides a display device having high display quality and reliability. This display device comprises: a first light-emitting element; a second light-emitting element disposed so as to be adjacent to the first light-emitting element; a first protective layer; a second protective layer; and an insulating layer. The first light-emitting element has a first pixel electrode, a first EL layer, a light-emitting layer, and a common electrode. The second light-receiving element has a second pixel electrode, a second EL layer, and the common electrode. The first EL layer is provided on the first pixel electrode, and the second EL layer is provided on the second pixel electrode. The first protective layer has a region that contacts a side surface of the first EL layer, and the second protective layer has a region that contacts a side surface of the second EL layer. The insulating layer is provided between the first protective layer and the second protective layer. The common electrode is provided on the first EL layer, on the second EL layer, on the first protective layer, on the second protective layer, and on the insulating layer.

Description

[Technical Field]

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

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

[0003] In recent years, there has been a growing demand for higher resolution display panels. 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) or augmented reality (AR).

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

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

[0006] Patent document 2 discloses a display device for VR using an organic EL element. [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 project] [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. One aspect of the present invention aims to provide a display device with a novel configuration.

[0009] One aspect of the present invention aims to provide a method for manufacturing a display device with high display quality. One aspect of the present invention aims to provide a method for manufacturing a display device with high reliability. One aspect of the present invention aims to provide a method for manufacturing a display device with low power consumption. One aspect of the present invention aims to provide a method for manufacturing a display device that is easily capable of high definition. One aspect of the present invention aims to provide a method for manufacturing a display device that combines high display quality and high definition. One aspect of the present invention aims to provide a method for manufacturing a display device with high contrast. One aspect of the present invention aims to provide a method for manufacturing a display device having a novel configuration.

[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 necessarily 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 has a first light-emitting element, a second light-emitting element arranged adjacent to the first light-emitting element, a first protective layer, a second protective layer, and an insulating layer. The first light-emitting element has a first pixel electrode, a first EL layer, and a common electrode. The second light-emitting element has a second pixel electrode, a second EL layer, and a common electrode. The first EL layer is provided on the first pixel electrode, the second EL layer is provided on the second pixel electrode, the first protective layer has a region in contact with the side surface of the first EL layer, the second protective layer has a region in contact with the side surface of the second EL layer, the insulating layer is provided between the first protective layer and the second protective layer, and the common electrode is provided on the first EL layer, the second EL layer, the first protective layer, the second protective layer, and the insulating layer, which is a display device.

[0012] Alternatively, in the above aspect, the insulating layer may contain an organic material.

[0013] Alternatively, in the above aspect, the insulating layer may contain a photosensitive resin.

[0014] Alternatively, in the above embodiment, the first protective layer and the second protective layer may have an inorganic material.

[0015] Alternatively, in the above embodiment, a common layer is provided between the first EL layer, the second EL layer, the first protective layer, the second protective layer, and the insulating layer and the common electrode, and the common layer may include at least one of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, or an electron injection layer in the first light-emitting element and the second light-emitting element.

[0016] Alternatively, in the above embodiment, there may be a region where the distance between the side surface of the first EL layer and the side surface of the second EL layer is 1 μm or less.

[0017] Alternatively, in the above embodiment, there may be a region where the distance between the side surface of the first EL layer and the side surface of the second EL layer is 100 nm or less.

[0018] Alternatively, in the above embodiment, the first light-emitting element has a third protective layer, the second light-emitting element has a fourth protective layer, the third protective layer has a region in contact with the side surface of the first pixel electrode, the fourth protective layer has a region in contact with the side surface of the second pixel electrode, and the insulating layer may be provided between the third protective layer and the fourth protective layer.

[0019] Alternatively, in the above embodiment, the third protective layer and the fourth protective layer may have an inorganic material.

[0020] A display module having a display device according to one aspect of the present invention and at least one of a connector and an integrated circuit is also an aspect of the present invention.

[0021] An electronic device comprising a display module according to one aspect of the present invention, and at least one of a housing, battery, camera, speaker, and microphone, is also according to one aspect of the present invention.

[0022] Alternatively, in one aspect of the present invention, a first pixel electrode and a second pixel electrode are formed on an insulating surface; a first EL film and a first sacrificial film are sequentially formed on the first pixel electrode and the second pixel electrode; a first sacrificial layer and a first EL layer are formed by processing the first sacrificial film and the first EL film, respectively, having a region that overlaps with the first pixel electrode; a first protective film is formed covering at least the side surface of the first EL layer and the side surface and top surface of the first sacrificial layer; a first protective layer is formed by processing the first protective film, having a region that contacts at least the side surface of the first EL layer; a second EL film and a second sacrificial film are sequentially formed on the first sacrificial layer and the second pixel electrode; and the second sacrificial film and the second EL film are processed, This is a method for manufacturing a display device, comprising: forming a second sacrificial layer and a second EL layer, each having a region overlapping with two pixel electrodes; forming a second protective film covering at least the side surfaces of the second EL layer and the side and top surfaces of the second sacrificial layer; processing the second protective film to form a second protective layer having a region in contact with at least the side surfaces of the second EL layer; forming an insulating film covering at least the top surface of the first sacrificial layer, the top surface of the second sacrificial layer, the side surfaces of the first protective layer, and the side surfaces of the second protective layer; processing the insulating film to form an insulating layer between the first protective layer and the second protective layer; removing the first and second sacrificial layers; and forming common electrodes on the first EL layer, the second EL layer, the first protective layer, the second protective layer, and the insulating layer.

[0023] Alternatively, in the above embodiment, the first protective film and the second protective film may be formed using ALD, sputtering, or CVD methods, and the insulating film may be formed using spin coating, spraying, screen printing, or painting methods.

[0024] Alternatively, in the above embodiment, before forming the common electrode, at least one of a hole injection layer, hole transport layer, hole blocking layer, electron blocking layer, electron transport layer, or electron injection layer may be formed as a common layer on the first EL layer, the second EL layer, the first protective layer, the second protective layer, and the insulating layer.

[0025] Alternatively, in the above embodiment, the second EL film may be processed such that there is a region where the distance between the side surface of the first EL layer and the side surface of the second EL layer is 1 μm or less.

[0026] Alternatively, in the above embodiment, the second EL film may be processed such that there is a region where the distance between the side surface of the first EL layer and the side surface of the second EL layer is 100 nm or less.

[0027] Alternatively, in the above embodiment, the first protective film may be processed to form a third protective layer having a region in contact with the side surface of the first pixel electrode in addition to a first protective layer having a region in contact with at least the side surface of the first EL layer, the second protective film may be processed to form a fourth protective layer having a region in contact with the side surface of the second pixel electrode in addition to a second protective layer having a region in contact with at least the side surface of the second EL layer, and the insulating film may be processed to form an insulating layer having a region in contact with the side surface of the first protective layer, the side surface of the second protective layer, the side surface of the third protective layer, and the side surface of the fourth protective layer. [Effects of the Invention]

[0028] According to one aspect of the present invention, a display device with high display quality can be provided. According to one aspect of the present invention, a highly reliable display device can be provided. According to one aspect of the present invention, a display device with low power consumption can be provided. According to one aspect of the present invention, a display device that can be easily made high-resolution can be provided. According to one aspect of the present invention, a display device that combines high display quality and high resolution can be provided. According to one aspect of the present invention, a display device with high contrast can be provided. According to one aspect of the present invention, a display device having a novel configuration can be provided.

[0029] According to one aspect of the present invention, a method for manufacturing a display device with high display quality can be provided. According to one aspect of the present invention, a method for manufacturing a highly reliable display device can be provided. According to one aspect of the present invention, a method for manufacturing a display device with low power consumption can be provided. According to one aspect of the present invention, a method for manufacturing a display device that is easily made high-resolution can be provided. According to one aspect of the present invention, a method for manufacturing a display device that combines high display quality and high resolution can be provided. According to one aspect of the present invention, a method for manufacturing a display device with high contrast can be provided. According to one aspect of the present invention, a method for manufacturing a display device having a novel configuration can be provided.

[0030] 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]

[0031] Figure 1A is a top view showing an example of the configuration of a display device. Figures 1B to 1E are cross-sectional views showing examples of the configuration of a display device. Figures 2A to 2C are cross-sectional views showing examples of the configuration of a display device. Figures 3A to 3F are top views showing examples of pixel configurations. Figures 4A to 4E are top views showing examples of pixel configurations. Figures 5A to 5E are cross-sectional views showing examples of methods for manufacturing a display device. Figures 6A to 6D are cross-sectional views showing examples of methods for manufacturing a display device. Figures 7A to 7D are cross-sectional views showing examples of methods for manufacturing a display device. Figures 8A and 8B are cross-sectional views showing examples of methods for manufacturing a display device. Figures 9A to 9D are cross-sectional views showing examples of methods for manufacturing a display device. Figures 10A and 10B are cross-sectional views showing examples of methods for manufacturing a display device. Figures 11A to 11C are cross-sectional views showing examples of the configuration of a display device. Figures 12A to 12C are cross-sectional views showing examples of the configuration of a display device. Figures 13A to 13D are cross-sectional views showing examples of the configuration of a display device. Figures 14A to 14D are cross-sectional views showing examples of the configuration of a display device. Figure 15 is a perspective view showing an example of a display device configuration. Figure 16A is a cross-sectional view showing an example of the configuration of a display device. Figures 16B and 16C are cross-sectional views showing an example of the configuration of a transistor. Figure 17 is a cross-sectional view showing an example of the configuration of a display device. Figures 18A and 18B are perspective views showing example configurations of display modules. Figure 19 is a cross-sectional view showing an example of the configuration of a display device. Figure 20 is a cross-sectional view showing an example of the configuration of a display device. Figure 21 is a cross-sectional view showing an example of the configuration of a display device. Figure 22 is a cross-sectional view showing an example of the configuration of a display device. Figure 23 is a cross-sectional view showing an example of the configuration of a display device. Figures 24A to 24F show examples of the configuration of light-emitting elements. Figures 25A and 25B show examples of electronic devices. Figures 26A to 26D show examples of electronic devices. Figures 27A to 27F show examples of electronic devices. Figures 28A to 28F show examples of electronic devices. [Modes for carrying out the invention]

[0032] 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. Therefore, the present invention is not to be construed as being limited to the contents of the following embodiments.

[0033] 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.

[0034] 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.

[0035] Furthermore, the ordinal numbers "1st," "2nd," 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" may be interchangeable depending on the circumstances. 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), for example, an image 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, a display module, or simply a display panel, etc.

[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, and a material with high electron injection properties, a bipolar material, and the like.

[0041] Furthermore, the light-emitting layer, as well as the layers containing materials with high hole injection, high hole transport, high electron transport, and high electron injection, bipolar materials, etc., 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, or 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] (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.

[0044] 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 or 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 elements are preferably organic EL elements (organic electroluminescent elements). 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.

[0045] When different colored EL layers are to be created between light-emitting elements, 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 influences 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 film outline 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.

[0046] 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.

[0047] 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 FMM may be referred to as MML (Metal Maskless) structured devices.

[0048] For simplicity, this section describes the process of creating two different colored light-emitting elements (a first light-emitting element and a second light-emitting element). First, a first pixel electrode and a second pixel electrode are formed on a substrate. Next, a first EL film and a first sacrificial film are formed sequentially on the first and second pixel electrodes, respectively. Then, a resist mask is formed on the first sacrificial film. Subsequently, the first sacrificial film and the first EL film are processed using the resist mask to form a first sacrificial layer and a first EL layer, respectively, which have regions overlapping with the first pixel electrode. In this specification, the sacrificial film may be referred to as a mask film, and the sacrificial layer may be referred to as a mask layer.

[0049] Next, a first protective film is formed that covers the sides of the first EL layer, the sides and top of the first sacrificial layer, and the sides and top of the second pixel electrode. Subsequently, the first protective film is processed to form a first protective layer having a region in contact with the sides of the first EL layer.

[0050] Next, a second EL film and a second sacrificial film are formed sequentially on the first sacrificial layer and the second pixel electrode. Subsequently, a resist mask is formed on the second sacrificial film. Then, using the resist mask, the second sacrificial film and the second EL film are processed to form a second sacrificial layer and a second EL layer, respectively, which have a region overlapping with the second pixel electrode.

[0051] Next, a second protective film is formed that covers the sides of the first protective layer, the sides of the second EL layer, the top and sides of the first sacrificial layer, and the top and sides of the second sacrificial layer. Subsequently, the second protective film is processed to form a second protective layer having a region in contact with the sides of the second EL layer.

[0052] In this way, the first EL layer and the second EL layer can be manufactured separately. Furthermore, a first protective layer having a region in contact with the side surface of the first EL layer and a second protective layer having a region in contact with the side surface of the second EL layer can be formed. By providing the first protective layer, the intrusion of impurities such as oxygen and water into the interior from the side surface of the first EL layer can be suppressed. Similarly, by providing the second protective layer, the intrusion of impurities such as oxygen and water into the interior from the side surface of the second EL layer can be suppressed. As a result, a display device according to one aspect of the present invention can be made into a highly reliable display device.

[0053] If impurities are present on the surface of the EL layer, these impurities may penetrate into the EL layer, potentially reducing the reliability of the display device. Therefore, it is preferable to remove impurities adhering to the surface of the first EL layer after its formation and before the formation of the first protective film covering the first EL layer, as this improves the reliability of the display device. Similarly, it is preferable to remove impurities adhering to the surface of the second EL layer after its formation and before the formation of the second protective film covering the second EL layer. For example, placing the substrate on which the first EL layer is formed under an inert gas atmosphere can remove impurities adhering to the surface of the first EL layer. Similarly, placing the substrate on which the second EL layer is formed under an inert gas atmosphere can remove impurities adhering to the surface of the second EL layer. As the inert gas, one or more selected from, for example, Group 18 elements (typically helium, neon, argon, xenon, and krypton) and nitrogen can be used.

[0054] Furthermore, when the EL layer comes into contact with air, oxygen and other impurities such as water contained in the air may penetrate into the interior of the EL layer. Here, after the formation of the first EL layer, the surface of the first EL layer is exposed until the first protective film is formed. Therefore, it is preferable to perform the processes from processing the first EL film to forming the first protective film in the same apparatus. This makes it possible to form the first protective film covering the first EL layer without exposing the first EL layer to air after processing the first EL film to form the first EL layer. Similarly, it is preferable to perform the processing of the second EL film and the formation of the second protective film in the same apparatus. As a result, it is possible to suppress the penetration of impurities contained in the air into the interior of the EL layer and improve the reliability of the display device. It is also preferable to perform other processes in the same apparatus, as this can suppress the exposure of the display device components to air during the manufacturing process of the display device and can increase the throughput in the manufacturing of the display device.

[0055] Next, the first sacrificial layer and the second sacrificial layer are removed. Finally, by forming a common electrode on the first EL layer, the second EL layer, the first protective layer, and the second protective layer, two-color light-emitting elements can be created. Specifically, a first light-emitting element having a first pixel electrode, a first EL layer, a first protective layer, and a common electrode, and a second light-emitting element having a second pixel electrode, a second EL layer, a second protective layer, and a common electrode can be created.

[0056] Furthermore, by repeating the above process up to the point of removing the sacrificial layer, it is possible to create three or more different colored light-emitting elements, thereby realizing a display device having three or four or more colored light-emitting elements.

[0057] In this case, if a gap is provided between the first light-emitting element and the second light-emitting element, the common electrode may enter the gap, causing the common electrode to be cut (stepped).

[0058] In one aspect of the present invention, an insulating layer is provided between a first EL layer and a second EL layer. Specifically, before removing the first sacrificial layer and the second sacrificial layer, an insulating film is formed to cover the upper surface of the first sacrificial layer, the upper surface of the second sacrificial layer, the side surface of the first protective layer, and the side surface of the second protective layer. Subsequently, the insulating film is processed to form an insulating layer between a first protective layer having a region in contact with the side surface of the first EL layer and a second protective layer having a region in contact with the side surface of the second EL layer.

[0059] By providing an insulating layer between the first EL layer and the second EL layer, the surface on which the common electrode is provided can be made less uneven, thereby suppressing the breakage of the common electrode. As a result, a highly reliable display device can be realized.

[0060] When EL layers of different colors are adjacent, it is difficult to reduce the distance 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 distance 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 distance 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, the aperture ratio can be 50% or more, 60% or more, 70% or more, 80% or more, and even 90% or more, and it is possible to achieve less than 100%.

[0061] 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.

[0062] Thus, the above manufacturing method makes it possible to realize a display device that integrates fine light-emitting elements. Therefore, there is no need 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.

[0063] 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.

[0064] [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.

[0065] In this specification, for example, light-emitting elements 110R, 110G, and 110B may be collectively referred to as light-emitting element 110. For example, when referring to light-emitting element 110, it refers to some or all of light-emitting elements 110R, 110G, and 110B. The same description applies to other elements.

[0066] 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. However, the arrangement method of the light-emitting elements is not limited to this; other arrangement methods such as delta arrangement or zigzag arrangement may be applied, or a pentile arrangement may be used.

[0067] 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 (e.g., quantum dot materials), and thermally activated delayed fluorescence (TADF) materials.

[0068] Figure 1A also shows the connecting electrode 111C and the common electrode 113, with the common electrode 113 indicated by a dashed line. The connecting electrode 111C is supplied with the potential supplied to the common electrode 113 (for example, the anode potential or cathode potential). The connecting electrode 111C is provided outside the display area where the light-emitting elements 110 are arranged. For example, the connecting electrode 111C can be provided along the outer perimeter of the display area. For example, the connecting electrode 111C 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 frame shape, etc.

[0069] Figure 1B is a schematic cross-sectional view corresponding to the dashed line A1-A2 in Figure 1A. Figure 1C is a schematic cross-sectional view corresponding to the dashed line B1-B2 in Figure 1A. Figure 1D is a schematic cross-sectional view corresponding to the dashed line C1-C2 in Figure 1A.

[0070] Figure 1B shows cross-sections of the light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B. Figure 1C shows a cross-section of the light-emitting element 110G. The light-emitting element 110 is provided on a layer 101 containing a transistor. The layer 101 containing the transistor is provided on a substrate (not shown).

[0071] A layered structure can be applied in which, for example, multiple transistors are provided in the transistor-containing layer 101, and an insulating layer is provided to cover these transistors. Here, as shown in Figures 1B and 1C, the transistor-containing layer 101 may have recesses between adjacent light-emitting elements 110. For example, recesses may be provided in the insulating layer located on the outermost surface of the transistor-containing layer 101. Note that recesses may not be provided between adjacent light-emitting elements 110.

[0072] The layer 101 containing the transistor preferably includes, for example, a pixel circuit, a scan line driving circuit (gate driver), and a signal line driving circuit (source driver). In addition to the above, it may also include an arithmetic circuit and a memory circuit.

[0073] The light-emitting element 110R includes a pixel electrode 111R, an EL layer 112R on the pixel electrode 111R, and a protective layer 131 having a region in contact with the side surface of the EL layer 112R. The light-emitting element 110G includes a pixel electrode 111G, an EL layer 112G on the pixel electrode 111G, and a protective layer 131 having a region in contact with the side surface of the EL layer 112G. The light-emitting element 110B includes a pixel electrode 111B, an EL layer 112B on the pixel electrode 111B, and a protective layer 131 having a region in contact with the side surface of the EL layer 112B.

[0074] Furthermore, a common layer 114 is provided on the EL layer 112R, EL layer 112G, EL layer 112B, and protective layer 131, and a common electrode 113 is provided on the common layer 114. In addition, the light-emitting element 110R may have a protective layer 131 that has a region in contact with the side surface of the pixel electrode 111R, as well as a protective layer 131 that has a region in contact with the side surface of the EL layer 112R. Similarly, the light-emitting element 110G may have a protective layer 131 that has a region in contact with the side surface of the pixel electrode 111G, as well as a protective layer 131 that has a region in contact with the side surface of the EL layer 112G. Furthermore, the light-emitting element 110B may have a protective layer 131 that has a region in contact with the side surface of the pixel electrode 111B, as well as a protective layer 131 that has a region in contact with the side surface of the EL layer 112B. Furthermore, the protective layer 131 having a region in contact with the side surface of the pixel electrode 111R, the protective layer 131 having a region in contact with the side surface of the pixel electrode 111G, and the protective layer 131 having a region in contact with the side surface of the pixel electrode 111B do not need to be provided. Also, the common layer 114 does not need to be provided.

[0075] Here, the number of protective layers 131 having regions in contact with the sides of the EL layer 112R, the number of protective layers 131 having regions in contact with the sides of the EL layer 112G, and the number of protective layers 131 having regions in contact with the sides of the EL layer 112B can be different from each other. Figures 1B and 1C show an example in which three protective layers 131 having regions in contact with the sides of the EL layer 112R are provided per side, two protective layers 131 having regions in contact with the sides of the EL layer 112G are provided per side, and one protective layer 131 having regions in contact with the sides of the EL layer 112B is provided per side. Also, Figures 1B and 1C show an example in which three protective layers 131 having regions in contact with the sides of the pixel electrode 111 are provided per side. The number of layers of the protective layer 131 is not limited to the examples shown in Figures 1B and 1C, and can be appropriately varied depending on the manufacturing method of the display device 100, as will be described in detail later.

[0076] EL layer 112R has a luminescent organic compound that emits light with intensity in at least the red wavelength range. EL layer 112G has a luminescent organic compound that emits light with intensity in at least the green wavelength range. EL layer 112B has a luminescent organic compound that emits light with intensity in at least the blue wavelength range.

[0077] Each of the EL layers 112R, 112G, and 112B has an emissive layer. The emissive layer is a layer containing an emissive material. The emissive layer may contain one or more types of emissive materials. As the emissive material, a material that exhibits an emission color such as blue, purple, blue-violet, green, yellow-green, yellow, orange, or red may be used as appropriate. In addition, a material that emits near-infrared light may be used as the emissive material.

[0078] Examples of luminescent materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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 material (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 material, 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 element.

[0083] The EL layer 112R, EL layer 112G, and EL layer 112B may further include layers other than the light-emitting layer, such as a material with high hole injection properties, a material with high hole transport properties, a hole blocking material, a material with high electron transport properties, a material with high electron injection properties, an electron blocking material, or a bipolar material (a material with high electron transport and hole transport properties).

[0084] The light-emitting element can be made from either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. The layers constituting the light-emitting element can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, or coating.

[0085] For example, EL layer 112R, EL layer 112G, and EL layer 112B may each have one or more of the following: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0086] Preferably, the EL layer 112R, EL layer 112G, and EL layer 112B each have an emissive layer and a carrier transport layer on the emissive layer. This suppresses the exposure of the emissive layer to the outermost surface during the manufacturing process of the display device 100, thereby reducing damage to the emissive layer. This improves the reliability of the light-emitting element.

[0087] 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).

[0088] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light-emitting layer. The hole transport layer is a layer containing a hole-transporting material. The hole-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having a hole mobility of 1 / Vs or higher are preferred. 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, or furan derivatives) or aromatic amines (compounds having an aromatic amine skeleton) that have high hole transport capabilities.

[0089] 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 2Materials 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, or 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, or other π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds, which are materials with high electron transport capabilities.

[0090] 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.

[0091] Examples of electron injection layers include lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), and calcium fluoride (CaF). x (where X is any number), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatrium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatrium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatrium (abbreviation: LiPPP), lithium oxide (LiO x Alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. Furthermore, the electron injection layer may be a laminated structure of two or more layers. For example, this laminated structure may consist of lithium fluoride as the first layer and ytterbium as the second layer.

[0092] Alternatively, an electron-transporting material may be used as the electron injection layer. For example, a compound having a lone pair of electrons and an electron-deficient heteroaromatic ring can be used as the electron-transporting material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), or a triazine ring can be used.

[0093] 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.

[0094] 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), or 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.

[0095] 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.

[0096] When a conductive film reflective to visible light is used as the pixel electrode 111, for example, silver, aluminum, titanium, tantalum, molybdenum, platinum, gold, titanium nitride, or tantalum nitride can be used. Alternatively, an alloy can be used as the pixel electrode 111. For example, an alloy containing silver can be used. As an example of a silver-containing alloy, an alloy containing silver, palladium, and copper can be used. Alternatively, an alloy containing aluminum can be used. Furthermore, these materials may be used in stacks of two or more layers.

[0097] 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 materials that are transparent to visible light include conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, indium tin oxide containing silicon, or indium zinc oxide containing silicon. 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. For example, the pixel electrode 111 can have a three-layer laminated structure of aluminum, titanium oxide, and indium tin oxide containing silicon.

[0098] 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, for example.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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 the thickest, while the EL layer 112B of the light-emitting element 110B that emits the shortest wavelength light can be 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.

[0103] As the common electrode 113, a conductive film that is translucent to visible light can be used. For example, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, or graphene can be used. 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 translucent. Furthermore, a laminated film of the above materials can be used as the conductive layer. For example, using a laminated film of a silver-magnesium alloy and indium tin oxide is preferable because it can enhance conductivity.

[0104] As described above, the protective layer 131 is provided so as to have a region in contact with the side surface of the EL layer 112. It is preferable that the protective layer 131 be a layer with high barrier properties against oxygen and water. This prevents impurities such as oxygen and water from entering the interior from the side surface of the EL layer 112. Thus, the display device 100 can be made into a highly reliable display device.

[0105] In this case, increasing the distance between adjacent EL layers 112 may reduce the aperture ratio of the pixels 103. On the other hand, decreasing the distance between adjacent EL layers 112 may reduce the barrier effect of the protective layer 131, making it easier for impurities to penetrate into the interior from the sides of the EL layers 112. Therefore, it is preferable that the distance between the side of one EL layer 112 and the side of an adjacent EL layer 112 is in a region of 3 nm to 200 nm, more preferably in a region of 3 nm to 150 nm, more preferably in a region of 5 nm to 150 nm, more preferably in a region of 5 nm to 100 nm, more preferably in a region of 10 nm to 100 nm, and more preferably in a region of 10 nm to 50 nm. By setting the distance between the side of one EL layer 112 and the side of an adjacent EL layer 112 within the above range, the display device 100 can be made into a display device with a high aperture ratio and high reliability.

[0106] The protective layer 131 can be an insulating layer having an inorganic material. As the protective layer 131, 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 in the formation of the protective layer 131 described later. In particular, by using an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by atomic layer deposition (ALD) as the protective layer 131, a film with fewer pinholes can be made, and a protective layer 131 with excellent function in protecting the EL layer 112 can be made.

[0107] 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.

[0108] The protective layer 131 can be formed using sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), or ALD. The ALD method, which provides good coverage, is preferable for forming the protective layer 131.

[0109] An insulating layer 132 is provided between adjacent light-emitting elements 110. The insulating layer 132 is located between each EL layer 112 of the light-emitting element 110. For example, it may be provided between two EL layers 112 that exhibit different colors. Alternatively, the insulating layer 132 may be provided between two EL layers 112 that exhibit the same color. Alternatively, the insulating layer 132 may be provided between two EL layers 112 that exhibit different colors, but not between two EL layers 112 that exhibit the same color. Furthermore, the insulating layer 132 can be located between each pixel electrode 111 of the light-emitting element 110. Specifically, the insulating layer 132 can be located between each protective layer 131 of the light-emitting element 110. A common layer 114 and a common electrode 113 are provided on the insulating layer 132.

[0110] Furthermore, the insulating layer 132 is arranged between the EL layers 112 between adjacent pixels so as to have a mesh-like (or grid-like, or matrix-like) shape when viewed from above.

[0111] By providing an insulating layer 132 between the EL layers 112 exhibiting different colors, it is possible to prevent the EL layers 112R, 112G, and 112B from coming into contact with each other. This effectively prevents current from flowing through two adjacent EL layers, which would otherwise result in unintended light emission. Therefore, the contrast can be enhanced, and the display device 100 can be made into a display device with high display quality. Furthermore, by providing an insulating layer 132 between each pixel electrode 111, it is possible to prevent the pixel electrodes 111 from coming into contact with each other. This effectively prevents short circuits between the pixel electrodes 111. Therefore, the display device 100 can be made into a highly reliable display device.

[0112] Furthermore, by providing an insulating layer 132 between adjacent light-emitting elements 110, the step difference caused by the region where the EL layer 112 is provided and the region where the EL layer 112 is not provided can be flattened. As a result, the coverage of the common electrode 113 can be improved compared to the case where an insulating layer 132 is not provided between adjacent light-emitting elements 110, for example, when an air gap is formed. Therefore, it is possible to suppress the occurrence of step breaks in the common electrode 113 and the resulting connection failure. In addition, it is possible to suppress the local thinning of the common electrode 113 due to the step difference, which increases the electrical resistance. As a result, the display device 100 can be made into a highly reliable display device.

[0113] Furthermore, if the insulating layer 132 is not provided between adjacent light-emitting elements 110 of the same color, and is formed only between light-emitting elements 110 of different colors, the insulating layer 132 can have a stripe shape when viewed from above. By making the insulating layer 132 stripe-shaped, the space required to form the insulating layer 132 is reduced compared to when the insulating layer 132 has a grid shape. Therefore, the aperture ratio of the display device 100 can be increased. In addition, when the insulating layer 132 has a stripe shape, adjacent EL layers 112 of the same color may be processed into strips so that they are continuous in the column direction.

[0114] The insulating layer 132 can preferably be an insulating layer having an organic material. For example, acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be used as the insulating layer 132. In addition, a photosensitive resin can be used as the insulating layer 132. The photosensitive resin can be a positive-type material or a negative-type material.

[0115] By forming the insulating layer 132 using a photosensitive resin, the insulating layer 132 can be manufactured solely through the exposure and development processes.

[0116] The common layer 114 is provided covering the EL layers 112R, 112G, and 112B. By configuring the display device 100 to have a common layer 114, the manufacturing process of the display device 100 can be simplified, thereby reducing the manufacturing cost of the display device 100. The common layer 114 and the common electrode 113 can be formed continuously without an etching process or the like in between. Therefore, the interface between the common layer 114 and the common electrode 113 can be made into a clean surface. This makes the display device 100 a highly reliable display device.

[0117] The common layer 114 is preferably a layer that includes one or more of the following: a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, or an electron injection layer. In a light-emitting element where the pixel electrode 111 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.

[0118] 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 110 from above.

[0119] 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.

[0120] Furthermore, a laminated film of an inorganic insulating film and an organic insulating film can 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, electrodes for a touch sensor, or a lens array, etc.) is provided above the protective layer 121.

[0121] Figure 1D 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 1D, an example is shown in which a common layer 114 is provided between the connecting electrode 111C and the common electrode 113, but the region 130 may be configured without a common layer 114. Figure 1E shows a cross-section corresponding to the dashed line C1-C2 shown in Figure 1A when the region 130 does not have a common layer 114. By configuring the region 130 without a common layer 114, the connecting electrode 111C and the common electrode 113 can be in contact, and the contact resistance can be further reduced.

[0122] 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. Furthermore, a sacrificial layer 145 is provided so as to have a region in contact with the side surface of the connecting electrode 111C, and a protective layer 131 is provided so as to have a region in contact with the side surface of the sacrificial layer 145. In addition, in the example shown in Figure 1D, a common layer 114 is provided on the connecting electrode 111C, the insulating layer 132, and the sacrificial layer 145. Note that Figure 1D shows an example in which three protective layers 131, each having a region in contact with the side surface of the sacrificial layer 145, are provided for each side surface, but the present invention is not limited to this, and as will be described in detail later, it can be appropriately varied depending on, for example, the manufacturing method of the display device 100. The sacrificial layer 145 will be described later.

[0123] Figure 2A shows an enlarged view of the area enclosed by the dashed square in Figure 1B. As shown in Figure 2A, the insulating layer 132 can be concave.

[0124] Figures 2B and 2C show modified versions of the configuration shown in Figure 2A. The configurations shown in Figures 2B and 2C differ from the configuration shown in Figure 2A in the shape of the insulating layer 132, etc.

[0125] The insulating layer 132 shown in Figure 2B has a flat upper surface. The insulating layer 132 shown in Figure 2C has a region that overlaps with the upper surface of the EL layer 112. Here, a sacrificial layer 145 is provided between the EL layer 112 and the insulating layer 132, so that the EL layer 112 and the insulating layer 132 do not come into contact. In Figure 2C, the sacrificial layer 145 is shown as a sacrificial layer 145R provided between the EL layer 112R and the insulating layer 132, and a sacrificial layer 145G provided between the EL layer 112G and the insulating layer 132.

[0126] [Pixel layout] Next, we will describe a pixel layout different from Figure 1A. There are no particular limitations on the arrangement of subpixels, and various methods can be applied. Examples of subpixel arrangements include stripe arrangements, S-stripe arrangements, matrix arrangements, delta arrangements, Bayer arrangements, and pentile arrangements.

[0127] Furthermore, the top surface shape of the sub-pixel can be, for example, a polygon such as a triangle, quadrilateral (including rectangles and squares), or pentagon, or a polygon with rounded corners, or an ellipse or a circle. Here, the top surface shape of the sub-pixel corresponds to the top surface shape of the light-emitting region of the light-emitting element.

[0128] The pixel 103 shown in Figure 3A has an S-stripe array applied to it. The pixel 103 shown in Figure 3A is composed of three subpixels: subpixel 103a, subpixel 103b, and subpixel 103c. For example, as shown in Figure 4A, subpixel 103a may be a blue subpixel B, subpixel 103b may be a red subpixel R, and subpixel 103c may be a green subpixel G.

[0129] The pixel 103 shown in Figure 3B has sub-pixels 103a with a roughly trapezoidal top surface shape with rounded corners, sub-pixels 103b with a roughly triangular top surface shape with rounded corners, and sub-pixels 103c with a roughly square or roughly hexagonal top surface shape with rounded corners. Furthermore, sub-pixel 103a has a larger light-emitting area than sub-pixel 103b. In this way, the shape and size of each sub-pixel can be determined independently. For example, the size of a sub-pixel can be reduced to a level that provides a more reliable light-emitting element. For example, as shown in Figure 4B, sub-pixel 103a may be a green sub-pixel G, sub-pixel 103b may be a red sub-pixel R, and sub-pixel 103c may be a blue sub-pixel B.

[0130] A Pentile array is applied to pixels 124a and 124b shown in Figure 3C. Figure 3C shows an example in which pixels 124a having subpixels 103a and 103b, and pixels 124b having subpixels 103b and 103c are arranged alternately. For example, as shown in Figure 4C, subpixel 103a may be a red subpixel R, subpixel 103b may be a green subpixel G, and subpixel 103c may be a blue subpixel B.

[0131] Pixels 124a and 124b, shown in Figures 3D and 3E, utilize a delta array. Pixel 124a has two subpixels (subpixels 103a and 103b) in the top row (1st row) and one subpixel (subpixel 103c) in the bottom row (2nd row). Pixel 124b has one subpixel (subpixel 103c) in the top row (1st row) and two subpixels (subpixels 103a and 103b) in the bottom row (2nd row). For example, as shown in Figure 4D, subpixel 103a may be a red subpixel R, subpixel 103b a green subpixel G, and subpixel 103c a blue subpixel B.

[0132] Figure 3D shows an example where each subpixel has a roughly square top shape with rounded corners, and Figure 3E shows an example where each subpixel has a circular top shape.

[0133] Figure 3F shows an example where the subpixels of each color are arranged in a zigzag pattern. Specifically, in a top view, the upper edges of two subpixels aligned in the column direction (for example, subpixels 103a and 103b, or subpixels 103b and 103c) are offset. For example, as shown in Figure 4E, subpixel 103a may be the red subpixel R, subpixel 103b may be the green subpixel G, and subpixel 103c may be the blue subpixel B.

[0134] In photolithography, the finer the pattern being processed, the more significant the effects of light diffraction become. This compromises the fidelity of transferring the photomask pattern through exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, patterns with rounded corners are likely to form. Consequently, the top surface shape of subpixels may be a polygon with rounded corners, an ellipse, or a circle.

[0135] Furthermore, in a method for manufacturing a display device according to one aspect of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the EL layer material and the curing temperature of the resist material, the curing of the resist film may be insufficient. A resist film that is not sufficiently cured may take a shape that deviates from the desired shape during processing. As a result, the top surface shape of the EL layer may become a polygon with rounded corners, an ellipse, or a circle. For example, if an attempt is made to form a resist mask with a square top surface, a resist mask with a circular top surface may be formed, resulting in a circular top surface shape for the EL layer.

[0136] Furthermore, in order to achieve the desired shape of the upper surface of the EL layer, a technique (OPC (Optical Proximity Correction) technique) may be used to pre-correct the mask pattern so that the design pattern and the transferred pattern match. Specifically, in the OPC technique, for example, a correction pattern is added to the corners of the shape on the mask pattern.

[0137] [Example of manufacturing method] 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 5A to 9A, 10A, and 10B are schematic cross-sectional views of each step in the method for manufacturing the display device illustrated below.

[0138] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed using sputtering, CVD, vacuum deposition, PLD, or ALD methods. CVD methods include plasma enhanced CVD (PECVD) and thermal CVD. One type of thermal CVD method is metal-organic CVD (MOCVD).

[0139] 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, or knife coating.

[0140] Furthermore, when processing the thin film that constitutes the display device, for example, photolithography can be used. In addition, the thin film may be processed by nanoimprint lithography, sandblasting, or lift-off lithography. Alternatively, island-shaped thin films may be directly formed by a film deposition method using a shielding mask such as a metal mask.

[0141] 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, for example by etching, 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.

[0142] 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.

[0143] For etching thin films, dry etching, wet etching, or sandblasting methods can be used.

[0144] To fabricate the display device 100, first, a layer 101 containing transistors is formed on a substrate (not shown). As mentioned above, the layer 101 containing transistors can be a laminated structure in which, for example, an insulating layer is provided so as to cover the transistors.

[0145] As the substrate, a substrate with sufficient heat resistance to withstand subsequent heat treatment can be used. When using an insulating substrate, glass substrates, quartz substrates, sapphire substrates, ceramic substrates, or organic resin substrates can be used. In addition, semiconductor substrates such as single-crystal semiconductor substrates, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon-germanium, and SOI substrates made from silicon or silicon carbide can be used.

[0146] Next, a conductive film that will become the pixel electrode 111 is deposited on the layer 101 containing the transistor. Specifically, for example, a conductive film that will become the pixel electrode 111 is deposited on the insulating surface of the layer 101 containing the transistor. Subsequently, a portion of the conductive film is etched away to form the pixel electrode 111R, pixel electrode 111G, pixel electrode 111B, and connecting electrode 111C on the layer 101 containing the transistor (Figure 5A).

[0147] When using a conductive layer that is reflective to visible light as a pixel electrode, it is preferable to use a material (for example, silver or aluminum) that has the highest possible reflectivity across the entire wavelength range of visible light. This not only improves the light extraction efficiency of the light-emitting element but also enhances color reproduction.

[0148] Next, an EL film 112Rf, which will later become the EL layer 112R, is formed on layer 101 containing the pixel electrode 111R, pixel electrode 111G, pixel electrode 111B, and transistor. Here, the EL film 112Rf can be formed so as not to overlap with the connecting electrode 111C. For example, by shielding the region containing the connecting electrode 111C with a metal mask and forming the EL film 112Rf, the EL film 112Rf can be formed so as not to overlap with the connecting electrode 111C. In this case, the metal mask does not need to shield the pixel region of the display unit, so it is not necessary to use a high-resolution mask.

[0149] 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 a hole injection layer, hole transport layer, hole blocking layer, electron blocking layer, electron transport layer, or electron injection layer 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.

[0150] Next, a sacrificial film 144Ra is formed on the EL film 112Rf, the connecting electrode 111C, and the layer 101 containing the transistor, and a sacrificial film 144Rb is formed on the sacrificial film 144Ra. In other words, a two-layer stacked sacrificial film is formed on the EL film 112Rf, the connecting electrode 111C, and the layer 101 containing the transistor. Note that the sacrificial film may be a single layer or a stacked structure of three or more layers. In subsequent steps, when forming a sacrificial film, a two-layer stacked sacrificial film is formed, but it may be a single layer or a stacked structure of three or more layers.

[0151] In this specification, for example, sacrificial films 144Ra and 144Rb may be collectively referred to as sacrificial film 144R. For example, when referring to sacrificial film 144R, it refers to either sacrificial film 144Ra or sacrificial film 144Rb, or both. The same description applies to other elements.

[0152] For the formation of the sacrificial films 144Ra and 144Rb, for example, sputtering, CVD, ALD (thermal ALD, PEALD), or vacuum deposition can be used. A formation method that causes minimal damage to the EL layer is preferred, and the sacrificial film 144Ra, which is formed directly on the EL film 112Rf, is preferably formed using the ALD or vacuum deposition method.

[0153] As the sacrificial film 144Ra, a metal film, alloy film, metal oxide film, semiconductor film, or an inorganic film such as an inorganic insulating film can be suitably used.

[0154] Furthermore, an oxide film can be used as the sacrificial film 144Ra. Typically, oxide films or oxynitride films such as silicon oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, hafnium oxide, and hafnium oxynitride can be used. Alternatively, a nitride film can be used as the sacrificial film 144Ra. Specifically, nitrides such as silicon nitride, aluminum nitride, hafnium nitride, titanium nitride, tantalum nitride, tungsten nitride, gallium nitride, or germanium nitride can be used. Such inorganic insulating materials can be formed using film deposition methods such as sputtering, CVD, or ALD, but the sacrificial film 144Ra formed directly on the EL film 112Rf is preferably formed using the ALD method.

[0155] Furthermore, as the sacrificial film 144Ra, metal materials such as nickel, tungsten, chromium, molybdenum, cobalt, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metal materials, can be used. In particular, it is preferable to use low-melting-point materials such as aluminum or silver.

[0156] Furthermore, metal oxides such as indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO) can be used as the sacrificial film 144Ra. In addition, indium oxide, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), or indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide) can be used. Alternatively, indium tin oxide containing silicon can also be used.

[0157] 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.

[0158] As the sacrificial film 144Rb, any of the materials listed above that can be used as the sacrificial film 144Ra can be used. Alternatively, one material can be selected as the sacrificial film 144Ra from the materials listed above that can be used as the sacrificial film 144Ra, and another material can be selected as the sacrificial film 144Rb. Furthermore, from the materials listed above that can be used as the sacrificial film 144Ra, one or more materials can be selected for the sacrificial film 144Ra, and one or more materials selected from materials other than those selected for the sacrificial film 144Ra can be used for the sacrificial film 144Rb.

[0159] Specifically, it is preferable to use a configuration in which aluminum oxide formed by the ALD method is used as the sacrificial film 144Ra, and silicon nitride formed by the sputtering method is used as the sacrificial film 144Rb. In this configuration, it is preferable to set the film deposition temperature during film deposition by the ALD method and the sputtering method to room temperature or higher and 120°C or lower, preferably room temperature or higher and 100°C or lower, as this reduces the effect on the EL film 112Rf. Furthermore, in the case of a laminated structure of sacrificial film 144Ra and sacrificial film 144Rb, it is preferable that the stress of the laminated structure is small. Specifically, it is preferable that the stress of the laminated structure be -500 MPa or higher and +500 MPa or lower, more preferably -200 MPa or higher and +200 MPa or lower, as this suppresses process problems such as film delamination and peeling.

[0160] The sacrificial film 144Ra 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 144Ra be a film that can be removed by a wet etching method that causes little damage to each EL film.

[0161] Furthermore, as the sacrificial film 144Ra, a material that is soluble in a chemically stable solvent may be used, at least for the film located on 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 144Ra. When forming the sacrificial film 144Ra, it is preferable to apply it using a wet deposition method while dissolved in a solvent such as water or alcohol, and then perform a heat treatment to evaporate the solvent. At this time, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to the EL film 112Rf.

[0162] Wet film deposition methods that can be used to form the sacrificial film 144Ra include spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0163] As the sacrificial film 144Ra, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used.

[0164] For the sacrificial film 144Rb, a film with a high etching selectivity ratio with the sacrificial film 144Ra should be used.

[0165] It is preferable to use an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by the ALD method as the sacrificial film 144Ra, and a metallic material such as nickel, tungsten, chromium, molybdenum, cobalt, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or an alloy material containing such a metallic material, formed by the sputtering method, as the sacrificial film 144Rb. In particular, it is preferable to use tungsten formed by the sputtering method as the sacrificial film 144Rb. Alternatively, an indium-containing metal oxide such as indium gallium zinc oxide (In-Ga-Zn oxide, also denoted as IGZO), formed by the sputtering method, may be used as the sacrificial film 144Rb. Furthermore, an inorganic material may be used as the sacrificial film 144Rb. For example, oxide films or nitride films such as silicon oxide films, silicon oxide nitride films, silicon nitride films, silicon nitride films, aluminum oxide films, aluminum oxide nitride films, and hafnium oxide films can be used.

[0166] Furthermore, as the sacrificial film 144Rb, an organic film that can be used for the EL film 112Rf may be used, for example. For example, the same organic film used for the EL film 112Rf, EL film 112Gf, or EL film 112Bf can be used as the sacrificial film 144Rb. Using such an organic film is preferable because, for example, the deposition equipment can be used in common with the EL film 112Rf. Moreover, for example, when etching the EL film 112Rf, the sacrificial film 144Rb can be removed at the same time, thus simplifying the process.

[0167] Next, a resist mask 143a is formed on the sacrificial film 144Rb (Figure 5B). The resist mask 143a can be made of a resist material containing a photosensitive resin, such as a positive-type resist material or a negative-type resist material.

[0168] Next, portions of the sacrificial film 144Rb and sacrificial film 144Ra that are not covered by the resist mask 143a are removed by etching to form island-shaped or strip-shaped sacrificial layers 145Rb and 145Ra. Here, the sacrificial layers 145Rb and 145Ra can be formed on the pixel electrode 111R and on the connecting electrode 111C.

[0169] Here, it is preferable to remove a portion of the sacrificial film 144Rb by etching using the resist mask 143a to form a sacrificial layer 145Rb, then remove the resist mask 143a, and subsequently etch the sacrificial film 144Ra using the sacrificial layer 145Rb as a hard mask. In this case, it is preferable to use etching conditions that have a high selectivity ratio with respect to the sacrificial film 144Ra for etching the sacrificial film 144Rb. Wet etching or dry etching can be used for etching to form the hard mask, but using dry etching can suppress pattern reduction.

[0170] 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.

[0171] When etching the sacrificial film 144Ra using the sacrificial layer 145Rb as a hard mask, the resist mask 143a can be removed while the EL film 112Rf is covered by the sacrificial film 144Ra. For example, if the EL film 112Rf comes into contact with oxygen, it may adversely affect the electrical characteristics of the light-emitting element 110R. Therefore, when removing the resist mask 143a using a method that uses oxygen gas, such as plasma ashing, it is preferable to etch the sacrificial film 144Ra using the sacrificial layer 145Rb as a hard mask.

[0172] Next, a portion of the EL film 112Rf not covered by the sacrificial layer 145Ra is removed by etching to form island-shaped or strip-shaped EL layers 112R (Figure 5C).

[0173] By etching the EL film 112Rf using a dry etching gas that does not contain oxygen as its main component, the deterioration of the EL film 112Rf is suppressed, and the display device 100 can be made into a highly reliable display device. Examples of etching gases that do not contain oxygen as their main component include CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, and group 18 elements. For example, helium can be used as a group 18 element. In addition, a mixed gas of the above gas and an oxygen-free diluent gas can be used as the etching gas. Note that the etching of the EL film 112Rf is not limited to the above, and may be performed by dry etching using other gases or by wet etching.

[0174] 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, problems 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.

[0175] Here, if the pixel electrode 111 has silicon-containing indium tin oxide, and the layer containing indium tin oxide is in contact with the EL film 112Rf, etching the EL film 112Rf with an oxygen-containing gas can suppress the disappearance of the indium tin oxide-containing layer on the pixel electrode 111G and the pixel electrode 111B. For example, etching the EL film 112Rf with a gas containing oxygen and a group 18 element such as argon can suitably suppress the disappearance of the indium tin oxide-containing layer. On the other hand, etching the EL film 112Rf with an oxygen-containing gas may leave residue of the EL film 112Rf on the pixel electrode 111G and the pixel electrode 111B. Here, etching the EL film 112Rf with a hydrogen-containing gas can suppress the remaining residue of the EL film 112Rf. For example, etching the EL film 112Rf with a gas containing hydrogen and a group 18 element such as argon can suitably suppress the remaining residue of the EL film 112Rf. However, when etching the EL film 112Rf, using hydrogen or argon may affect the EL film 112Rf. Specifically, if hydrogen is used to etch the EL film 112Rf, hydrogen may penetrate the EL film 112Rf, potentially degrading its reliability. Also, if argon is used for etching the EL film 112Rf, films formed near the EL film 112Rf (e.g., pixel electrodes or sacrificial films) may be introduced into the EL film 112Rf as impurities. Therefore, the person performing the etching should select the most appropriate gas for the EL film 112Rf as needed.

[0176] As described above, for example, by etching the EL film 112Rf using a hydrogen-containing gas, and then etching the EL film 112Rf using an oxygen-containing gas, it is possible to suppress the remaining residue of the EL film 112Rf on the pixel electrode 111G and pixel electrode 111B, while suppressing the disappearance of the indium tin oxide-containing layer. For example, it is preferable to perform half-etching of the EL film 112Rf using a mixed gas of hydrogen and argon, and then etch the EL film 112Rf using a mixed gas of oxygen and argon. This effectively suppresses both the remaining residue of the EL film 112Rf on the pixel electrode 111G and pixel electrode 111B, and the disappearance of the indium tin oxide-containing layer. The hydrogen-containing gas may be a gas with a hydrogen purity of 99% or higher. The oxygen-containing gas may be a gas with an oxygen purity of 99% or higher.

[0177] When the EL film 112Rf is etched to form the EL layer 112R, if impurities are attached to the side surface of the EL layer 112R, these impurities may penetrate into the interior of the EL layer 112R in subsequent processes. This may reduce the reliability of the display device 100. Therefore, it is preferable to remove impurities attached to the surface of the EL layer 112R after its formation to improve the reliability of the display device 100.

[0178] Impurities adhering to the surface of the EL layer 112R can be removed, for example, by irradiating the surface of the EL layer 112R with an inert gas. Immediately after the formation of the EL layer 112R, the surface of the EL layer 112R is exposed. Specifically, the side surfaces of the EL layer 112R are exposed. Therefore, after the formation of the EL layer 112R, for example, by placing the substrate on which the EL layer 112R is formed under an inert gas atmosphere, impurities adhering to the EL layer 112R can be removed. As the inert gas, one or more selected from, for example, Group 18 elements (typically helium, neon, argon, xenon, and krypton) and nitrogen can be used.

[0179] Next, a protective film 131Rf, which will later become the protective layer 131R, is formed to cover the upper surface of the layer 101 containing the transistor, the sides and upper surfaces of the pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B, the sides of the EL layer 112R, the sides of the sacrificial layer 145Ra, and the sides and upper surface of the sacrificial layer 145Rb (Figure 5D). The protective film 131Rf can be formed using sputtering, CVD, MBE, PLD, or ALD, but the ALD method, which has good coverage, can be preferably used.

[0180] Furthermore, the protective film 131Rf can be an insulating layer having an inorganic material, and it is particularly preferable that it be an insulating layer having aluminum oxide or silicon oxide.

[0181] The thickness of the protective film 131Rf is preferably, for example, 0.5 nm to 30 nm, more preferably 1 nm to 10 nm, and even more preferably 1 nm to 5 nm. Furthermore, it is preferable that the protective film 131Rf has a thickness and type that does not contain pinholes.

[0182] Here, if the EL layer 112R comes into contact with air, oxygen and other impurities such as water contained in the air may penetrate into the interior of the EL layer 112R. After the formation of the EL layer 112R, the surface of the EL layer 112R, specifically the side surface of the EL layer 112R, is exposed until the protective film 131Rf is formed. Therefore, it is preferable to perform the processes from etching the EL film 112Rf to forming the protective film 131Rf in the same apparatus. This makes it possible to form the protective film 131Rf that covers the EL layer 112R without exposing the EL layer 112R to air after etching the EL film 112Rf. Thus, it is possible to suppress the penetration of impurities contained in the air into the interior of the EL layer 112R, and to make the display device 100 a highly reliable display device. Furthermore, performing other processes in the same apparatus is preferable because it is possible to suppress the exposure of the components of the display device 100 to air during the manufacturing process of the display device 100, and to increase the throughput in the manufacturing of the display device 100.

[0183] Next, the protective film 131Rf is etched to form a protective layer 131R (Figure 5E). The protective layer 131R is formed to have a region that contacts the side surface of the EL layer 112R. The protective layer 131R is also formed to have a region that contacts the side surface of the pixel electrode 111R, the side surface of the pixel electrode 111G, the side surface of the pixel electrode 111B, the side surface of the sacrificial layer 145Ra, and the side surface of the sacrificial layer 145Rb. However, if the thickness of the protective film 131Rf is thin, some of the side surfaces of the pixel electrode 111R, the side surface of the pixel electrode 111G, the side surface of the pixel electrode 111B, the side surface of the sacrificial layer 145Ra, or the side surface of the sacrificial layer 145Rb may not contact the protective layer 131R.

[0184] By forming the protective layer 131R such that it has a region in contact with the side surface of the EL layer 112R, it is possible to suppress the intrusion of impurities such as oxygen and water into the interior from the side surface of the EL layer 112R in subsequent processes. Therefore, the display device 100 can be made into a highly reliable display device.

[0185] Etching the protective film 131Rf by anisotropic etching is preferable because it allows for the suitable formation of the protective layer 131 without the need for patterning using, for example, photolithography. For example, forming the protective layer 131 without patterning using photolithography simplifies the manufacturing process of the display device 100, thereby reducing the manufacturing cost of the display device 100. The protective film 131Rf can be etched by, for example, a dry etching method. For example, the protective film 131Rf can be etched using an etching gas that can be used when etching the sacrificial film 144Ra or the sacrificial film 144Rb.

[0186] By the way, in the process shown in Figures 5B to 5C, etching the EL film 112Rf using an oxygen-containing gas changes the surface state of, for example, the pixel electrode 111G and the pixel electrode 111B. For example, the surfaces of the pixel electrode 111G and the pixel electrode 111B become hydrophilic. For example, if the upper surface of the pixel electrode 111G and the pixel electrode 111B is a layer containing indium tin oxide, etching the EL film 112Rf using an oxygen-containing gas makes the indium tin oxide-containing layer hydrophilic. Here, the EL film formed in a later step to have a region in contact with the pixel electrode 111G, and the EL film formed to have a region in contact with the pixel electrode 111B, are hydrophobic. The adhesion between a hydrophilic surface and a hydrophobic surface is lower than the adhesion between hydrophilic surfaces and between hydrophobic surfaces. Therefore, if the surfaces of the pixel electrode 111G and the pixel electrode 111B are hydrophilic, the adhesion to the EL film formed in a later step will be low. Therefore, in subsequent processes, the EL film may peel off at the interface with the pixel electrode 111G or the interface with the pixel electrode 111B. Furthermore, if the EL film 112Rf is etched using an oxygen-containing gas, in addition to the above-mentioned changes in surface condition, the work function of the surfaces of the pixel electrode 111G and the pixel electrode 111B may change.

[0187] Therefore, by performing a hydrophobic treatment on the surface of the pixel electrode 111G and the surface of the pixel electrode 111B, peeling of the EL film formed in a later process can be suppressed. Thus, the display device 100 can be made into a highly reliable display device. In addition, the yield in the manufacture of the display device 100 can be increased, making the display device 100 a low-cost display device. The hydrophobic treatment is preferably performed after the formation of the protective layer 131R.

[0188] Hydrophobic treatment can be performed, for example, by fluorine modification of the pixel electrodes 111G and 111B. Fluorine modification can be performed, for example, by treatment with a fluorine-containing gas, heat treatment, plasma treatment in a fluorine-containing gas atmosphere, etc. As the fluorine-containing gas, for example, fluorine gas can be used, and for example, fluorocarbon gas can be used. As the fluorocarbon gas, for example, lower fluorinated carbon gases such as carbon tetrafluoride (CF4) gas, C4F6 gas, C2F6 gas, C4F8 gas, or C5F8 can be used. In addition, as the fluorine-containing gas, for example, SF6 gas, NF3 gas, or CHF3 gas can be used. Furthermore, helium gas, argon gas, or hydrogen gas can be added to these gases as appropriate.

[0189] Furthermore, the surfaces of the pixel electrodes 111G and 111B can be made hydrophobic by performing plasma treatment in a gas atmosphere containing a group 18 element such as argon, followed by treatment with a silylation agent. Hexamethyldisilazane (HMDS) or trimethylsilylimidazole (TMSI) can be used as the silylation agent. In addition, the surfaces of the pixel electrodes 111G and 111B can also be made hydrophobic by performing plasma treatment in a gas atmosphere containing a group 18 element such as argon, followed by treatment with a silane coupling agent.

[0190] By performing plasma treatment on the surfaces of pixel electrodes 111G and 111B in a gas atmosphere containing a group 18 element such as argon, damage can be inflicted on the surfaces of pixel electrodes 111G and 111B. This makes it easier for methyl groups contained in silylation agents such as HMDS to bond to the surfaces of pixel electrodes 111G and 111B. It also facilitates silane coupling by silane coupling agents. As a result, by performing plasma treatment on the surfaces of pixel electrodes 111G and 111B in a gas atmosphere containing a group 18 element such as argon, followed by treatment with a silylation agent or a silane coupling agent, the surfaces of pixel electrodes 111G and 111B can be made hydrophobic.

[0191] Treatment using a silylation agent or silane coupling agent can be carried out by applying the silylation agent or silane coupling agent using, for example, a spin coating method or a dip method. Alternatively, treatment using a silylation agent or silane coupling agent can be carried out by forming a film containing a silylation agent or a film containing a silane coupling agent on the pixel electrode 111G and the pixel electrode 111B using, for example, a vapor phase method. In the vapor phase method, first, the silylation agent or silane coupling agent is introduced into the atmosphere by volatilizing the material containing the silylation agent or the material containing the silane coupling agent. Subsequently, the substrate on which the pixel electrode 111G and the pixel electrode 111B are formed is placed in the atmosphere. This allows a film containing a silylation agent or silane coupling agent to be formed on the pixel electrode 111G and the pixel electrode 111B, and the surfaces of the pixel electrode 111G and the pixel electrode 111B can be made hydrophobic.

[0192] Next, an EL film 112Gf, which will later become the EL layer 112G, is formed on the sacrificial layer 145Rb, the protective layer 131R, the pixel electrode 111G, the pixel electrode 111B, and the layer 101 containing the transistor. By forming the EL film 112Gf after forming the sacrificial layer 145R and the protective layer 131R, it is possible to prevent the EL film 112Gf from coming into contact with the EL layer 112R. For example, the description of the formation of the EL film 112Gf can be found in the description of the formation of the EL film 112Rf.

[0193] Next, a sacrificial film 144Ga is formed on the EL film 112Gf, on the sacrificial layer 145Rb, and on the transistor-containing layer 101, and a sacrificial film 144Gb is formed on the sacrificial film 144Ga. Subsequently, a resist mask 143b is formed on the sacrificial film 144Gb (Figure 6A). For details on the formation of the sacrificial film 144Ga, sacrificial film 144Gb, and resist mask 143b, refer to the descriptions of the formation of the sacrificial film 144Ra, sacrificial film 144Rb, and resist mask 143a, respectively.

[0194] Next, portions of the sacrificial layers 144Gb and 144Ga that are not covered by the resist mask 143b are removed by etching to form island-shaped or strip-shaped sacrificial layers 145Gb and 145Ga. The resist mask 143b is also removed. Here, the sacrificial layers 145Gb and 145Ga can be formed on the pixel electrode 111G. For details on the formation of the sacrificial layers 145Gb and 145Ga, and the removal of the resist mask 143b, etc., refer to the descriptions for the formation of the sacrificial layer 145Rb and 145Ra, and the removal of the resist mask 143a, etc., respectively.

[0195] Next, a portion of the EL film 112Gf not covered by the sacrificial layer 145Ga is removed by etching to form island-shaped or strip-shaped EL layers 112G (Figure 6B). For example, the description of the formation of EL layer 112R can be used to refer to the description of the formation of EL layer 112R. Also, similar to EL layer 112R, it is preferable to remove impurities adhering to the surface of EL layer 112G. For example, after the formation of EL layer 112G, placing the substrate on which the EL layer 112G is formed under an inert gas atmosphere can remove impurities adhering to EL layer 112G.

[0196] Next, a protective film 131Gf, which will later become the protective layer 131G, is formed to cover the upper surface of the transistor-containing layer 101, the upper surface of the pixel electrode 111B, the side surface of the EL layer 112G, the side surface of the protective layer 131R, the upper surface of the sacrificial layer 145Rb, the side surface of the sacrificial layer 145Ga, and the side surface and upper surface of the sacrificial layer 145Gb (Figure 6C). For example, the formation of the protective film 131Gf can be described in the description of the formation of the protective film 131Rf. Here, it is preferable to perform the processes from etching the EL film 112Gf to forming the protective film 131Gf in the same apparatus, because this allows the protective film 131Gf covering the EL layer 112G to be formed without exposing the EL layer 112G to air.

[0197] Next, the protective layer 131G is formed by etching the protective film 131Gf (Figure 6D). The protective layer 131G is formed to have a region in contact with the side surface of the EL layer 112G. The protective layer 131G is also formed to have a region in contact with the side surface of the protective layer 131R, the side surface of the sacrificial layer 145Ga, and the side surface of the sacrificial layer 145Gb. Note that if the thickness of the protective film 131Gf is thin, some of the side surfaces of the protective layer 131R, the side surface of the sacrificial layer 145Ga, or the side surface of the sacrificial layer 145Gb may not be in contact with the protective layer 131G. For example, the formation of the protective layer 131G can be described in the description of the formation of the protective layer 131R.

[0198] Next, an EL film 112Bf, which will later become the EL layer 112B, is formed on the sacrificial layer 145Rb, the sacrificial layer 145Gb, the protective layer 131R, the protective layer 131G, the pixel electrode 111B, and the layer 101 containing the transistor. By forming the EL film 112Bf after forming the sacrificial layer 145G and the protective layer 131G, it is possible to prevent the EL film 112Bf from coming into contact with the EL layer 112G. For example, the description of the formation of the EL film 112Rf can be used to describe the formation of the EL film 112Bf.

[0199] Next, a sacrificial film 144Ba is formed on the EL film 112Bf, on the sacrificial layer 145Rb, and on the layer 101 containing the transistor, and a sacrificial film 144Bb is formed on the sacrificial film 144Ba. Subsequently, a resist mask 143c is formed on the sacrificial film 144Bb (Figure 7A). For details on the formation of the sacrificial film 144Ba, sacrificial film 144Bb, and resist mask 143c, refer to the descriptions of the formation of the sacrificial film 144Ra, sacrificial film 144Rb, and resist mask 143a, respectively.

[0200] Next, portions of the sacrificial layers 144Bb and 144Ba that are not covered by the resist mask 143c are removed by etching to form island-shaped or strip-shaped sacrificial layers 145Bb and 145Ba. The resist mask 143c is also removed. Here, the sacrificial layers 145Bb and 145Ba can be formed on the pixel electrode 111B. For details on the formation of the sacrificial layers 145Bb and 145Ba, and the removal of the resist mask 143c, etc., refer to the descriptions for the formation of the sacrificial layer 145Rb and 145Ra, and the removal of the resist mask 143a, etc., respectively.

[0201] Next, a portion of the EL film 112Bf not covered by the sacrificial layer 145Ba is removed by etching to form island-shaped or strip-shaped EL layers 112B (Figure 7B). For example, the description of the formation of EL layer 112R can be used to describe the formation of EL layer 112B. In addition, it is preferable to remove impurities adhering to the surface of EL layer 112B, similar to EL layer 112R and EL layer 112G. For example, after the formation of EL layer 112B, placing the substrate on which the EL layer 112B is formed under an inert gas atmosphere can remove impurities adhering to EL layer 112B.

[0202] Next, a protective film 131Bf, which will later become the protective layer 131B, is formed to cover the upper surface of the transistor-containing layer 101, the side surfaces of the EL layer 112B, the side surfaces of the protective layer 131G, the upper surface of the sacrificial layer 145Rb, the upper surface of the sacrificial layer 145Gb, the side surfaces of the sacrificial layer 145Ba, and the side and upper surfaces of the sacrificial layer 145Bb (Figure 7C). For example, the formation of the protective film 131Bf can be described in the description of the formation of the protective film 131Rf. Here, it is preferable to perform the processes from etching the EL film 112Bf to forming the protective film 131Bf in the same apparatus, because this allows the protective film 131Bf covering the EL layer 112B to be formed without exposing the EL layer 112B to air.

[0203] Next, the protective layer 131B is formed by etching the protective film 131Bf (Figure 7D). The protective layer 131B is formed to have a region in contact with the side surface of the EL layer 112B. The protective layer 131B is also formed to have a region in contact with the side surface of the protective layer 131G, the side surface of the sacrificial layer 145Ba, and the side surface of the sacrificial layer 145Bb. Note that if the thickness of the protective film 131Bf is thin, some of the side surfaces of the protective layer 131G, the sacrificial layer 145Ba, or the sacrificial layer 145Bb may not be in contact with the protective layer 131B. For example, the formation of the protective layer 131B can be described in the description of the formation of the protective layer 131R.

[0204] Next, sacrificial layers 145Rb, 145Gb, and 145Bb are removed using etching or the like (Figure 8A). When etching sacrificial layer 145b, it is preferable to use conditions that have a high selectivity ratio with sacrificial layer 145a. It is also possible to omit the removal of sacrificial layer 145b. Furthermore, Figure 8A shows an example in which a portion of the protective layer 131 is removed by the removal of sacrificial layer 145b, and the uppermost surface of the protective layer 131 having a region in contact with the side surface of the EL layer 112 coincides with the upper surface of the sacrificial layer 145a, but the present invention is not limited to this. For example, the uppermost surface of the protective layer 131 having a region in contact with the side surface of the EL layer 112 may be higher than the upper surface of the sacrificial layer 145a.

[0205] In this specification, for example, sacrificial layers 145Ra, 145Ga, and 145Ba may be collectively referred to as sacrificial layer 145a, and sacrificial layers 145Rb, 145Gb, and 145Bb may be collectively referred to as sacrificial layer 145b. For example, sacrificial layer 145a refers to some or all of sacrificial layers 145Ra, 145Ga, and 145Ba, and sacrificial layer 145b refers to some or all of sacrificial layers 145Rb, 145Gb, and 145Bb. Similar descriptions shall apply to other elements.

[0206] Next, an insulating film 132f, which will later become an insulating layer 132, is formed to cover the upper surface of the sacrificial layer 145a, the side surface of the protective layer 131, and the upper surface of the layer 101 containing the transistor (Figure 8B). It is preferable to use an insulating film having an organic material as the insulating film 132f, and it is preferable to use a resin as the organic material. Alternatively, a photosensitive resin can be used as the insulating film 132f. The photosensitive resin can be a positive-type material or a negative-type material.

[0207] When a photosensitive resin is used as the insulating film 132f, the insulating film 132f can be formed using methods such as spin coating, spraying, screen printing, or painting.

[0208] As shown in Figure 8B, the insulating film 132f may have smooth irregularities that reflect the unevenness of the surface to which it is formed. Furthermore, the insulating film 132f may be flattened.

[0209] Next, an insulating layer 132 is formed (Figure 9A). By using a photosensitive resin as the insulating film 132f, the insulating layer 132 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 132 can be formed without using dry etching methods, etc. Thus, the process can be simplified. In addition, damage to the EL layer 112 due to etching of the insulating film 132f can be reduced. Furthermore, a portion of the upper part of the insulating layer 132 may be etched to adjust the surface height.

[0210] Alternatively, an insulating layer 132 may be formed by etching the upper surface of the insulating film 132f substantially uniformly. This process of uniform etching and planarization is also called etch-back.

[0211] In forming the insulating layer 132, the exposure and development process and the etch-back process may be used in combination.

[0212] Figure 9B shows an enlarged view of the area enclosed by the dashed square in Figure 9A. As shown in Figure 9B, the insulating layer 132 can be concave. Here, the height of the upper end of the insulating layer 132 can be less than or equal to the height of the upper surface of the sacrificial layer 145. For example, if an EL layer 112R is provided on the left side of the cross-section and an EL layer 112G is provided on the right side, and an insulating layer 132 is provided between the EL layer 112R and the EL layer 112G, the height of the upper left end of the insulating layer 132 can be less than or equal to the height of the upper surface of the sacrificial layer 145Ra, and the height of the upper right end of the insulating layer 132 can be less than or equal to the height of the upper surface of the sacrificial layer 145Ga.

[0213] Figures 9C and 9D show modified versions of the configuration shown in Figure 9B. The configurations shown in Figures 9C and 9D differ from the configuration shown in Figure 9B in the shape of the insulating layer 132, etc.

[0214] The insulating layer 132 shown in Figure 9C has a flat top surface. In the example shown in Figure 9C, the height of the upper left edge of the insulating layer 132 is equal to the height of the top surface of the sacrificial layer 145Ra, and the height of the upper right edge of the insulating layer 132 is equal to the height of the top surface of the sacrificial layer 145Rb.

[0215] The insulating layer 132 shown in Figure 9D has a region that overlaps with the upper surface of the EL layer 112 via the sacrificial layer 145a. By further processing the insulating layer 132 from the state shown in Figure 9D, the insulating layer 132 can be made into the shape shown in Figure 9B or Figure 9C.

[0216] Next, the sacrificial layers 145Ra, 145Ga, and 145Ba are removed using etching or the like (Figure 10A). When etching the sacrificial layer 145a, it is preferable to use a method that causes as little damage as possible to the EL layer 112. In this case, a portion of the sacrificial layer 145a that is in contact with the side surface of the connecting electrode 111C may remain. In Figure 10A, a portion of the protective layer 131 is removed by the removal of the sacrificial layer 145a, and the uppermost surface of the protective layer 131 that is in contact with the side surface of the EL layer 112 coincides with the upper surface of the EL layer 112, but the present invention is not limited to this. For example, the uppermost surface of the protective layer 131 that is in contact with the side surface of the EL layer 112 may be higher than the upper surface of the EL layer 112.

[0217] In this specification, when simply referred to as sacrificial layer 145, it refers to any of the following: sacrificial layer 145Ra, sacrificial layer 145Ga, sacrificial layer 145Ba, sacrificial layer 145Rb, sacrificial layer 145Gb, or sacrificial layer 145Bb. The same applies to other elements.

[0218] Next, a common layer 114 is formed on the EL layer 112, the protective layer 131, the insulating layer 132, and the sacrificial layer 145a. After that, a common electrode 113 is formed on the common layer 114. The common electrode 113 can be formed by, for example, sputtering or vacuum deposition. If a configuration is not adopted in which the common layer 114 is provided on the connecting electrode 111C, a metal mask that shields the connecting electrode 111C can be used when forming the common layer 114. In this case, the metal mask does not need to shield the pixel area of ​​the display unit, so there is no need to use a high-resolution mask.

[0219] Through the above process, the light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B can be manufactured.

[0220] Next, a protective layer 121 is formed on the common electrode 113 (Figure 10B). For forming 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, when an organic insulating film is used as the protective layer 121, using an inkjet method for forming the organic insulating film is preferred because it allows for the formation of a uniform film in the desired area.

[0221] The display device 100 can be manufactured through the above process.

[0222] As described above, in the method for manufacturing a display device according to one aspect of the present invention, a shadow mask such as a metal mask is not used, and instead, the EL layer is created using, for example, a photolithography method and an etching method. This makes it possible to create a fine pattern for the EL layer. Therefore, the method for manufacturing a display device according to one aspect of the present invention makes it possible to manufacture a display device with high resolution and a high aperture ratio. Furthermore, it is possible to manufacture a high-resolution display device and a large-scale display device. Moreover, because the EL layer can be created separately, it is possible to manufacture a display device that is extremely vivid, has high contrast, and has high display quality.

[0223] [Configuration Example_2] Figure 11A is a schematic cross-sectional view corresponding to the dashed line A1-A2 in Figure 1A. Figure 11B is a schematic cross-sectional view corresponding to the dashed line B1-B2 in Figure 1A. Figure 11C is a schematic cross-sectional view corresponding to the dashed line C1-C2 in Figure 1A. Figures 11A, 11B, and 11C are modified examples of the configurations shown in Figures 1B, 1C, and 1D, differing in that the side surface of the pixel electrode 111R coincides with the side surface of the EL layer 112R, the side surface of the pixel electrode 111G coincides with the side surface of the EL layer 112G, and the side surface of the pixel electrode 111B coincides with the side surface of the EL layer 112B.

[0224] Figure 12A is a schematic cross-sectional view corresponding to the dashed-dotted line A1-A2 in Figure 1A. Figure 12B is a schematic cross-sectional view corresponding to the dashed-dotted line B1-B2 in Figure 1A. Figure 12C is a schematic cross-sectional view corresponding to the dashed-dotted line C1-C2 in Figure 1A. Figures 12A, 12B, and 12C are modified examples of the configurations shown in Figures 1B, 1C, and 1D, differing in that the side surface of the EL layer 112R is located outside the side surface of the pixel electrode 111R, the side surface of the EL layer 112G is located outside the side surface of the pixel electrode 111G, and the side surface of the EL layer 112B is located outside the side surface of the pixel electrode 111B. In the configurations shown in Figures 12A and 12B, the EL layer 112 is provided so as to cover the side surface of the pixel electrode 111.

[0225] Figure 13A is a schematic cross-sectional view corresponding to the dashed-dotted line A1-A2 in Figure 1A. Figure 13B is a schematic cross-sectional view corresponding to the dashed-dotted line B1-B2 in Figure 1A. Figure 13C is a schematic cross-sectional view corresponding to the dashed-dotted line C1-C2 in Figure 1A. Figures 13A, 13B, and 13C are modified examples of the configurations shown in Figures 1B, 1C, and 1D, differing in that a protective layer 133 is provided. Figure 13D is an enlarged view of the area enclosed by the square dashed-dotted line in Figure 13A.

[0226] The protective layer 133 is provided between the insulating layer 132, the protective layer 131, the sacrificial layer 145, and the common layer 114. The protective layer 133 may have an area that overlaps with a part of the EL layer 112. The protective layer 133 does not have to have an area that overlaps with the sacrificial layer 145. Furthermore, if, for example, the protective layer 131 that overlaps with the pixel electrode 111 is not provided, the protective layer 133 does not have to have an area that overlaps with the protective layer 131.

[0227] The protective layer 133 is preferably a layer with high barrier properties against oxygen and water. This prevents impurities such as oxygen and water contained in the insulating layer 132, which may have an organic insulating material such as resin, from penetrating the common layer 114. Thus, the display device 100 can be made into a highly reliable display device.

[0228] As the protective layer 133, an inorganic insulating material can be used, for example, a nitride. Specifically, silicon nitride, aluminum nitride, or hafnium nitride can be used as the protective layer 133. Furthermore, the protective layer 133 can be formed using, for example, sputtering, CVD, MBE, PLD, or ALD. In particular, it is preferable to use silicon nitride formed by sputtering as the protective layer 133.

[0229] Figure 14A is a schematic cross-sectional view corresponding to the dashed-dotted line A1-A2 in Figure 1A. Figure 14B is a schematic cross-sectional view corresponding to the dashed-dotted line B1-B2 in Figure 1A. Figure 14C is a schematic cross-sectional view corresponding to the dashed-dotted line C1-C2 in Figure 1A. Figures 14A, 14B, and 14C are modified examples of the configurations shown in Figures 1B, 1C, and 1D, differing in that protective layers 133a and 133b are provided. Figure 14D is an enlarged view of the area enclosed by the square dashed-dotted line in Figure 14A.

[0230] The protective layer 133a is provided between the protective layer 131 and the insulating layer 132. The protective layer 133b is provided between the insulating layer 132, protective layer 133a, protective layer 131, the sacrificial layer 145 and the common layer 114. In other words, the insulating layer 132 is covered by the protective layers 133a and 133b. The protective layer 133b may have an area that overlaps with a part of the EL layer 112. The protective layer 133b does not have to have an area that overlaps with the sacrificial layer 145. Furthermore, if, for example, the protective layer 131 that overlaps with the pixel electrode 111 is not provided, the protective layer 133b does not have to have an area that overlaps with the protective layer 131.

[0231] It is preferable that protective layers 133a and 133b be layers with high barrier properties against oxygen and water. This prevents impurities such as oxygen and water contained in the insulating layer 132, which may contain an organic insulating material such as resin, from penetrating the common layer 114. It also prevents impurities contained in the insulating layer 132 from penetrating the EL layer 112 via the protective layer 131. Therefore, the display device 100 can be made into a highly reliable display device.

[0232] The protective layers 133a and 133b can be made of the same materials as the protective layer 133 shown in Figures 13A, 13B, and 13C, and can be formed using the same film deposition method. For example, as protective layers 133a and 133b, silicon nitride formed by sputtering is typically preferred because it provides a high barrier against oxygen and water.

[0233] 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.

[0234] (Embodiment 2) This embodiment describes an example of the configuration of a display device according to one aspect of the present invention.

[0235] 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.

[0236] [Display Module_1] Figure 15 shows a perspective view of the display device 100A, and Figure 16A shows a cross-sectional view of the display device 100A.

[0237] The display device 100A has a configuration in which substrate 452 and substrate 451 are bonded together. In Figure 15, substrate 452 is clearly indicated by a dashed line.

[0238] The display device 100A includes a display unit 462, a circuit 464, and wiring 465, etc. Figure 15 shows an example in which IC 473 and FPC 472 are mounted on the display device 100A. Therefore, the configuration shown in Figure 15 can also be described as a display module having the display device 100A, an IC (integrated circuit), and an FPC. Note that the display device included in this display module is not limited to the display device 100A, but may also be the display device 100B described later.

[0239] For example, a scan line drive circuit can be used as circuit 464.

[0240] 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.

[0241] Figure 15 shows an example in which IC 473 is provided on the substrate 451 using the COG 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 module having the display device 100A may be configured without an IC. Alternatively, the IC may be mounted on an FPC, for example, using the COF method.

[0242] [Display device 100A] Figure 16A shows an example of a cross-section obtained by cutting a portion of the display device 100A, 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.

[0243] The display device 100A shown in Figure 16A has a transistor 201, a transistor 205, a light-emitting element 110R that emits red light, a light-emitting element 110G that emits green light, and a light-emitting element 110B that emits blue light, etc., between substrates 451 and 452. Here, in the display device 100A, the laminated structure from substrate 451 to insulating layer 214 corresponds to the layer 101 containing the transistors in Embodiment 1.

[0244] The light-emitting elements 110R, 110G, and 110B can be the light-emitting elements exemplified in Embodiment 1.

[0245] 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 R, G, and B, and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). If there are four such subpixels, examples of such four subpixels include subpixels of four colors: R, G, B, and white (W), and subpixels of four colors: R, G, B, and Y.

[0246] The protective layer 121 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 16A, the space 443 surrounded by the substrate 452, the adhesive layer 442, and the protective layer 121 is filled with an inert gas (such as nitrogen or argon), indicating 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 protective layer 121 may be filled with a resin different from that of the adhesive layer 442. The protective layer 121 can be configured as illustrated in Embodiment 1.

[0247] In the openings provided in the insulating layers 214, 215, and 213 such that the upper surface of the conductive layer 222b of the transistor 205 is exposed, a portion of the conductive layer 418R, conductive layer 418G, and conductive layer 418B are formed along the bottom and side surfaces of the opening. The conductive layers 418R, 418G, and 418B are each connected to the conductive layer 222b of the transistor 205. The pixel electrode contains a material that reflects visible light, and the counter electrode contains a material that transmits visible light. In addition, another portion of the conductive layer 418R, conductive layer 418G, and conductive layer 418B is provided on the insulating layer 214.

[0248] Pixel electrodes 111R, 111G, and 111B are provided on conductive layers 418R, 418G, and 418B, respectively.

[0249] Furthermore, as shown in Figure 16A, insulating layers 414 may be provided on the conductive layers 418R, 418G, and 418B, respectively, between the EL layer 112R of the light-emitting element 110R, the EL layer 112G of the light-emitting element 110G, and the EL layer 112B of the light-emitting element 110B.

[0250] The pixel electrodes exemplified in Embodiment 1 can be applied to the pixel electrodes 111R, 111G, and 111B.

[0251] An insulating layer 132 is provided in the region between the light-emitting element 110R and the light-emitting element 110G, which is on the insulating layer 214, and in the region between the light-emitting element 110G and the light-emitting element 110B, which is on the insulating layer 214. The insulating layer 132 can be configured as illustrated in Embodiment 1.

[0252] The display device 100A is a top-emission type display device. Therefore, the light emitted by the light-emitting element is emitted towards the substrate 452. It is preferable to use a material with high transmittance to visible light for the substrate 452.

[0253] Both transistors 201 and 205 are formed on the substrate 451. These transistors can be manufactured using the same materials and processes.

[0254] 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.

[0255] 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.

[0256] 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 oxynitride film, silicon oxide film, silicon nitride oxide film, aluminum oxide film, or 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.

[0257] Here, organic insulating films often have lower barrier properties than inorganic insulating films. Therefore, it is preferable that the organic insulating film has an opening near the edge of the display device 100A. This prevents impurities from entering through the organic insulating film from the edge of the display device 100A. Alternatively, the organic insulating film may be formed so that its edge is inward from the edge of the display device 100A, so that the organic insulating film is not exposed at the edge of the display device 100A.

[0258] 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.

[0259] In the region 228 shown in Figure 16A, an opening is formed in the two-layer laminated structure of the insulating layer 214 and the insulating layer 132 on the insulating layer 214. A protective layer 121 is formed to cover the opening. By using an inorganic layer as the protective layer 121, 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 100A can be improved.

[0260] 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.

[0261] The transistor structure of the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, or an inverse staggered transistor 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.

[0262] 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.

[0263] 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 having a crystalline region in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0264] The semiconductor layer of the transistor preferably has a metal oxide (also referred to as an oxide semiconductor). That is, the display device of the present embodiment preferably uses a transistor (hereinafter also referred to as an OS transistor) using a metal oxide for the channel formation region. Alternatively, the semiconductor layer of the transistor may have silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystalline silicon).

[0265] The semiconductor layer preferably has, for example, indium, one or more kinds of M (M is 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 kinds selected from aluminum, gallium, yttrium, and tin.

[0266] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also denoted as IGZO) as the semiconductor layer.

[0267] When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably not less than the atomic ratio of M. Examples of the atomic ratios of the metal elements in such an In-M-Zn oxide include compositions of In:M:Zn = 1:1:1 or in the vicinity thereof, In:M:Zn = 1:1:1.2 or in the vicinity thereof, In:M:Zn = 2:1:3 or in the vicinity thereof, In:M:Zn = 3:1:2 or in the vicinity thereof, In:M:Zn = 4:2:3 or in the vicinity thereof, In:M:Zn = 4:2:4.1 or in the vicinity thereof, In:M:Zn = 5:1:3 or in the vicinity thereof, In:M:Zn = 5:1:6 or in the vicinity thereof, In:M:Zn = 5:1:7 or in the vicinity thereof, In:M:Zn = 5:1:8 or in the vicinity thereof, In:M:Zn = 6:1:6 or in the vicinity thereof, In:M:Zn = 5:2:5 or in the vicinity thereof, and the like. The composition in the vicinity means that it includes a range of ±30% of the desired atomic ratio.

[0268] For example, when the atomic ratio is described as In:Ga:Zn = 4:2:3 or in the vicinity thereof, when the atomic ratio of In is 4, it includes cases where the atomic ratio of Ga is 1 or more and 3 or less, and the atomic ratio of Zn is 2 or more and 4 or less. Also, when the atomic ratio is described as In:Ga:Zn = 5:1:6 or in the vicinity thereof, when the atomic ratio of In is 5, it includes cases where the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is 5 or more and 7 or less. Also, when the atomic ratio is described as In:Ga:Zn = 1:1:1 or in the vicinity thereof, when the atomic ratio of In is 1, it includes cases where the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is greater than 0.1 and 2 or less.

[0269] The transistors included in circuit 464 and the transistors included in display unit 462 may have the same structure or different structures. The structures of the plurality of transistors included in circuit 464 may all be the same or there may be two or more types. Similarly, the structures of the plurality of transistors included in display unit 462 may all be the same or there may be two or more types.

[0270] A connection portion 204 is provided in the region of substrate 451 that does not overlap with substrate 452. At the connection portion 204, wiring 465 is electrically connected to FPC 472 via conductive layer 466, conductive layer 468, and connection layer 242. Conductive layers 466 and 468 can be conductive films obtained by processing the same conductive film as the pixel electrodes, or conductive films obtained by processing a laminated film of the same conductive film as the pixel electrodes and the same conductive film as the optical adjustment layer. On the upper surface of the connection portion 204, the conductive layer 468 is exposed. This allows the connection portion 204 and FPC 472 to be electrically connected via the connection layer 242.

[0271] It is preferable to provide a light-shielding layer 417 on the surface of the substrate 452 that faces the substrate 451. In addition, various optical components can be arranged on the outside of the substrate 452. Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (diffusion films, etc.), anti-reflective layers, and light-collecting films. Furthermore, an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, or an impact-absorbing layer may be arranged on the outside of the substrate 452.

[0272] By providing a protective layer 121 that covers the light-emitting element, it is possible to suppress the ingress of impurities such as water into the light-emitting element and improve the reliability of the light-emitting element.

[0273] In the region 228 near the edge of the display device 100A, it is preferable that the insulating layer 215 and the protective layer 121 are in contact with each other through an opening in 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 121 are in contact with each other. This makes it possible to suppress the entry of impurities into the display unit 462 from the outside through the organic insulating film. Therefore, the reliability of the display device 100A can be improved.

[0274] 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.

[0275] 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.

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

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

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

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

[0280] As the adhesive layer 442, various types of curing adhesives can be used, such as UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, or anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

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

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

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

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

[0285] Figure 16B is a cross-sectional view showing an example configuration of transistor 209, and Figure 16C is a cross-sectional view showing an example configuration of transistor 210. Transistors 209 and 210 can be applied to, for example, transistors 201 and 205 shown in Figure 16A.

[0286] Transistors 209 and 210 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a semiconductor layer 231 having a channel formation region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 that functions as a gate insulating layer, a conductive layer 223 that functions as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel formation region 231i. The insulating layer 225 is located between the conductive layer 223 and the channel formation region 231i. Also, an insulating layer 218 may be provided to cover the transistor 209 or the transistor 210.

[0287] The conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n through openings provided in the insulating layer 215 and the insulating layer 225. One of the conductive layer 222a and the conductive layer 222b functions as a source, and the other functions as a drain.

[0288] In FIG. 16B, an example in which the insulating layer 225 covers the upper surface and the side surface of the semiconductor layer 231 is shown. The conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n through openings provided in the insulating layer 225 and the insulating layer 215.

[0289] On the other hand, in the transistor 210 shown in FIG. 16C, the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231 and does not overlap with the low-resistance region 231n. For example, the structure shown in FIG. 16C can be fabricated by processing the insulating layer 225 using the conductive layer 223 as a mask. In FIG. 16C, the insulating layer 215 is provided covering the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n through the openings of the insulating layer 215.

[0290] ​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.

[0291] 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 costs and implementation costs.

[0292] Furthermore, it is preferable to use a transistor in which a metal oxide is present in the semiconductor that forms the channel, as at least one of the transistors included in the pixel circuit. 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 referred to as off-current) in the off state, making it possible to 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.

[0293] 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. A more suitable example is a configuration in which OS transistors are used as switches to control conduction and non-conduction between wiring, and LTPS transistors are used as transistors to control current.

[0294] 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.

[0295] On the other hand, another transistor provided in the pixel circuit functions as a switch to control the selection and deselection of pixels, and can 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 drain is electrically connected to the source line (signal line). It is preferable to use an OS transistor for the selection transistor. This makes it possible to maintain the gradation of pixels even when the frame frequency is significantly reduced (e.g., 1 fps or less), and thus power consumption can be reduced by stopping the driver when displaying still images.

[0296] Thus, one aspect of the present invention makes it possible to realize a display device that combines a high aperture ratio, high resolution, high display quality, and low power consumption.

[0297] [Display device 100B] Figure 17 is a cross-sectional view showing an example configuration of the display device 100B. The main difference between the display device 100B and the display device 100A is that the display device 100B is a bottom-emission type display device. Parts that are the same as those of the display device 100A are omitted from the explanation.

[0298] In the display device 100B, the light emitted by the light-emitting element 110 is emitted towards the substrate 451. It is preferable to use a material with high transmittance to visible light for the substrate 451. On the other hand, the light transmittance of the material used for the substrate 452 is not a requirement.

[0299] It is preferable to provide a light-shielding layer 417 between the substrate 451 and the transistor 201, and between the substrate 451 and the transistor 205. Figure 17 shows an example in which a light-shielding layer 417 is provided on the substrate 451, an insulating layer 253 is provided on the light-shielding layer 417 and on the substrate 451, and transistors 201 and 205 are provided on the insulating layer 253.

[0300] 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.

[0301] (Embodiment 3) In this embodiment, a different configuration example of a display device will be described.

[0302] The display device of this embodiment can be a high-definition display device. Therefore, the display device of this embodiment can be used in the display section of wearable devices that can be worn on the head, such as information terminals (wearable devices) such as wristwatches and bracelets, as well as VR devices such as head-mounted displays and AR devices such as glasses.

[0303] [Display Module_2] Figure 18A shows a perspective view of the display module 280. The display module 280 includes a display device 100C and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100C, but may also be the display device 100D, display device 100E, or display device 100F, which will be described later.

[0304] 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.

[0305] Figure 18B 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.

[0306] The pixel section 284 has a plurality of periodically arranged pixels 103. A magnified view of one pixel 103 is shown on the right side of Figure 18B. Pixel 103 has light-emitting elements 110R, 110G, and 110B, each with a different light-emitting color. It is preferable to arrange the plurality of light-emitting elements in a stripe arrangement as shown in Figure 18B. By using a stripe arrangement, the light-emitting elements of one embodiment of the present invention can be arranged at high density, thereby providing a high-definition display device. Furthermore, various arrangement methods such as delta arrangement or pentile arrangement can be applied.

[0307] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0308] A single pixel circuit 283a is a circuit that controls the light emission of the three light-emitting elements of a single pixel 103. 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 capacitor for each light-emitting element. In this case, a gate signal is input to the gate of the selection transistor, and a video signal is input to either the source or the drain. This realizes an active-matrix display device.

[0309] 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 scan line drive circuit and a signal 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.

[0310] 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.

[0311] 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 103 at an extremely high density, enabling an extremely high resolution of the display section 281. For example, it is preferable that the pixels 103 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.

[0312] 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 watches.

[0313] [Display device 100C] The display device 100C shown in Figure 19 includes a substrate 301, light-emitting elements 110R, 110G, 110B, a capacitor 240, and a transistor 310.

[0314] The transistor 310 is a transistor having a channel formation 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 a source or drain. The insulating layer 314 is provided covering the side surface of the conductive layer 311.

[0315] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0316] Furthermore, an insulating layer 261 is provided covering the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0317] 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.

[0318] 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.

[0319] An insulating layer 255 is provided covering the capacitance 240, and light-emitting elements 110R, 110G, and 110B are provided on the insulating layer 255. A protective layer 121 is provided on the light-emitting elements 110R, 110G, and 110B, and a substrate 420 is bonded to the upper surface of the protective layer 121 by a resin layer 419. Substrate 420 corresponds to substrate 292 in Figure 18A. Furthermore, the laminated structure from substrate 301 to insulating layer 255 corresponds to layer 101 containing the transistor in Embodiment 1.

[0320] 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 and insulating layer 243, a conductive layer 241 embedded in the insulating layer 254, and plugs 271 embedded in the insulating layer 261.

[0321] [Display device 100D] The display device 100D shown in Figure 20 differs from the display device 100C mainly in its transistor configuration. Note that explanations of parts similar to those of the display device 100C may be omitted.

[0322] Transistor 320 is a transistor in which a metal oxide is applied to the semiconductor layer where the channel is formed.

[0323] 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.

[0324] Substrate 331 corresponds to substrate 291 in Figures 18A and 18B. An insulating substrate or a semiconductor substrate can be used as substrate 331.

[0325] 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.

[0326] 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.

[0327] The semiconductor layer 321 is provided on the insulating layer 326. Preferably, the semiconductor layer 321 has a metal oxide film having semiconductor properties.

[0328] A pair of conductive layers 325 are provided in contact with the semiconductor layer 321 and function as source and drain electrodes.

[0329] 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. An insulating film similar to that used for the insulating layer 332 can be used for the insulating layer 328.

[0330] 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.

[0331] 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.

[0332] 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.

[0333] 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, 264, and 328. Here, it is preferable that the plug 274 has a conductive layer 274a that covers the sides of the openings of each 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.

[0334] In the display device 100D, the configuration from the insulating layer 254 to the substrate 420 is the same as in the display device 100C. In the display device 100D, the laminated structure from the substrate 331 to the insulating layer 255 corresponds to the layer 101 containing the transistor in Embodiment 1.

[0335] [Display device 100E] The display device 100E shown in Figure 21 has a configuration in which transistors 310A and 310B, each with a channel formed on a semiconductor substrate, are stacked.

[0336] The display device 100E has a structure in which a substrate 301B on which a transistor 310B, a capacitor 240, and each light-emitting element are provided, and a substrate 301A on which a transistor 310A is provided are bonded together. In the display device 100E, the laminated structure from substrate 301A to insulating layer 255 corresponds to the layer 101 containing the transistor in Embodiment 1.

[0337] 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 301 (the surface side of substrate 301A). On the other hand, a conductive layer 341 is provided on substrate 301A on an insulating layer 261.

[0338] The conductive layer 341 and the conductive layer 342 are joined together, thereby electrically connecting substrate 301A and substrate 301B.

[0339] 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.

[0340] [Display device 100F] The display device 100F shown in Figure 22 has a configuration in which a transistor 310 with a channel formed on a substrate 301 and a transistor 320 containing a metal oxide on a semiconductor layer in which the channel is formed are stacked. In the display device 100F, the stacked structure from the substrate 301 to the insulating layer 255 corresponds to the layer 101 containing the transistor in Embodiment 1. Note that parts similar to those of the display devices 100C and 100D may be omitted from the explanation.

[0341] 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.

[0342] 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 (scan line drive circuit, signal 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.

[0343] This configuration allows for the formation of not only pixel circuits but also, for example, driving circuits directly beneath the light-emitting elements, making it possible to miniaturize the display device compared to cases where the driving circuits are located around the display area.

[0344] [Display device 100G] The display device 100G shown in Figure 23 has an insulating layer 257 on top of an insulating layer 255, and a light-emitting element 110R, a light-emitting element 110G, a light-emitting element 110B, and a connecting electrode 111C are provided on the insulating layer 257. Conductive layers 247R, 247G, 247B, and 248 are embedded in the insulating layer 255. Plugs 256R, 256G, and 256B are also embedded in the insulating layer 255 and the insulating layer 257.

[0345] The pixel electrode 111R of the light-emitting element 110R is electrically connected to the conductive layer 247R via a plug 256R. The pixel electrode 111G of the light-emitting element 110G is electrically connected to the conductive layer 247G via a plug 256G. The pixel electrode 111B of the light-emitting element 110B is electrically connected to the conductive layer 247B via a plug 256B. The configuration of the layers below the insulating layer 255 can be the same as the configuration of the layers below the insulating layer 254 in, for example, the display device 100C, display device 100D, display device 100E, or display device 100F.

[0346] For example, silicon oxide can be used as the insulating layer 255, and silicon nitride can be used as the insulating layer 257. Furthermore, the conductive layers 247R, 247G, 247B, and 248 can have a laminated structure consisting of, for example, a layer containing titanium, a layer containing titanium nitride, and a layer containing aluminum.

[0347] The conductive layer 248 is provided in region 135, which is the region between the display region where the light-emitting element 110 is provided and the region 130 where the connecting electrode 111C is provided. The conductive layer 248 can also be provided in the same layer as conductive layers 247R, 247G, and 247B.

[0348] Here, the area of ​​the conductive layer 248 when viewed from above is larger than the areas of conductive layers 247R, 247G, and 247B. Therefore, the stress on the film provided on top of the conductive layer 248 is not easily relieved, and peeling tends to occur. As shown in Figure 23, by providing a slit 249 in the conductive layer 248, a configuration can be made that makes it easier to relieve the stress on the film provided on top, thereby suppressing the occurrence of peeling. Therefore, the display device 100G can be a highly reliable display device.

[0349] 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.

[0350] (Embodiment 4) This embodiment describes a light-emitting element that can be used in a display device according to one aspect of the present invention.

[0351] <Example of light-emitting element configuration> As shown in Figure 24A, the light-emitting element 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).

[0352] 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 24A is referred to as a single structure.

[0353] Furthermore, Figure 24B shows a modified example of the EL layer 786 of the light-emitting element shown in Figure 24A. Specifically, the light-emitting element shown in Figure 24B has a layer 4430-1 on the lower electrode 772, a layer 4430-2 on layer 4430-1, an emissive layer 4411 on layer 4430-2, a layer 4420-1 on the emissive 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.

[0354] Furthermore, as shown in Figures 24C and 24D, 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.

[0355] Furthermore, as shown in Figures 24E and 24F, 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 24E and 24F 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 element capable of high-brightness emission can be made.

[0356] In Figure 24C, the light-emitting layers 4411, 4412, and 4413 may be made of the same light-emitting material.

[0357] 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 24D 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.

[0358] Furthermore, in Figure 24E, 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 that emit different types 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 24F shows an example in which a colored layer 785 is further provided.

[0359] Furthermore, in Figures 24C, 24D, 24E, and 24F, as shown in Figure 24B, layer 4420 and layer 4430 may be a laminated structure consisting of two or more layers.

[0360] A structure in which each light-emitting element produces a different emission color (in this case, blue (B), green (G), and red (R)) is sometimes called an SBS (Side By Side) structure.

[0361] The light-emitting color of the light-emitting element can be red, green, blue, cyan, magenta, yellow, or white, depending on the material constituting the EL layer 786. Furthermore, the color purity can be further enhanced by adding a microcavity structure to the light-emitting element.

[0362] A light-emitting element 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 in color, a light-emitting element that emits white light as a whole can be obtained. The same applies to light-emitting elements that have three or more light-emitting layers.

[0363] 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), or O (orange).

[0364] This embodiment can be combined with other embodiments as appropriate.

[0365] (Embodiment 5) This embodiment describes metal oxides that can be used in the OS transistor described in the above embodiment.

[0366] 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, or tin. 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.

[0367] Furthermore, metal oxides can be formed by sputtering, CVD methods such as MOCVD, or ALD methods.

[0368] <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.

[0369] 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.

[0370] 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.

[0371] 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. In contrast, a spot-like pattern is observed in the diffraction pattern of an IGZO film deposited at room temperature, rather than 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.

[0372] <<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. Furthermore, non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS: amorphous-like oxide semiconductors), and amorphous oxide semiconductors.

[0373] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0374] [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.

[0375] Each of the above-mentioned crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of one minute crystal, the maximum diameter of that crystalline region will be less than 10 nm. When a crystalline region is composed of many minute crystals, the size of that crystalline region may be around several tens of nanometers.

[0376] 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.

[0377] When structural analysis of a CAAC-OS film is performed using, for example, an XRD instrument, 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 peak indicating c-axis orientation (value of 2θ) may vary depending on the type or composition of the metal elements constituting the CAAC-OS.

[0378] 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.

[0379] 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 a pentagonal or heptagonal lattice arrangement. 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.

[0380] 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 the transistor's 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 effectively than In oxide.

[0381] 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 (e.g., 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.

[0382] [nc-OS] nc-OS exhibits periodicity in atomic arrangement in minute regions (e.g., regions between 1 nm and 10 nm, particularly between 1 nm and 3 nm). In other words, nc-OS contains minute crystals. These minute crystals are also called nanocrystals because their size is, for example, between 1 nm and 10 nm, particularly between 1 nm and 3 nm. Furthermore, nc-OS shows no regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Consequently, depending on the analytical method, nc-OS may be indistinguishable from a-like OS or amorphous oxide semiconductors. For example, when structural analysis of an nc-OS film is performed using an XRD instrument, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Also, when electron diffraction (also called limited-field electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of the nanocrystals (e.g., 50 nm or larger), a diffraction pattern resembling a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystal (for example, 1 nm to 30 nm), an electron diffraction pattern may be obtained in which multiple spots are observed within a ring-shaped region centered on a direct spot.

[0383] [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.

[0384] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0385] [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 the 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.

[0386] 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.

[0387] 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.

[0388] Specifically, the first region described above is a region whose main component is indium oxide or indium zinc oxide, etc. The second region described above is a region whose main component is gallium oxide or 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.

[0389] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

[0390] 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.

[0391] 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.

[0392] 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.

[0393] 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.

[0394] On the other hand, the second region has 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.

[0395] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulation due to the second region work complementaryly to give CAC-OS a switching function (on / off function). In other words, CAC-OS has conductive function in part of the material, insulating function in part of the material, and semiconductor function as a whole. By separating the conductive function and the insulating function, both functions can be maximized. Therefore, by using CAC-OS in a transistor, a high on-current (I on ), high field-effect mobility (μ), and good switching operation can be achieved.

[0396] Furthermore, transistors using CAC-OS offer high reliability. Therefore, CAC-OS is ideal for various semiconductor devices, including display devices.

[0397] Oxide semiconductors can take on diverse structures, each possessing different properties. One embodiment of the present invention may include two or more of the following: amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0398] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0399] By using the above-mentioned oxide semiconductor in transistors, it is possible to realize transistors with high field-effect mobility. Furthermore, it is possible to realize highly reliable transistors.

[0400] It is preferable to use an oxide semiconductor with a low carrier concentration for the 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 -3 or less, still more preferably 1×10 11 cm -3 or less, even more preferably 1×10 10 cm -3 and less than 1×10 -9 cm -3 or more. When reducing the carrier concentration of the oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced and the density of defect levels may be reduced. In this specification and the like, a low impurity concentration and a low density of defect levels are referred to as highly pure intrinsic or substantially highly pure intrinsic. In some cases, an oxide semiconductor with a low carrier concentration is referred to as a highly pure intrinsic or substantially highly pure intrinsic oxide semiconductor.

[0401] In addition, since an oxide semiconductor film that is highly pure intrinsic or substantially highly pure intrinsic has a low density of defect levels, the density of trap levels may also be low.

[0402] In addition, the charge trapped in the trap level of the oxide semiconductor has a long time required to disappear and may behave like a fixed charge. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high trap level density may have unstable electrical characteristics.

[0403] Therefore, in order to stabilize the electrical characteristics of the transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. In addition, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in the adjacent film. Examples of the impurity include hydrogen, nitrogen, an alkali metal, an alkaline earth metal, iron, nickel, and silicon.

[0404] <Impurity> Here, we will explain the effects of various impurities in oxide semiconductors.

[0405] In oxide semiconductors, the presence of silicon or carbon, which are Group 14 elements, leads to the formation of defect levels in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are compared by 2 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 17 atoms / cm 3 The following applies:

[0406] 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:

[0407] 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 3More preferably 5 × 10 17 atoms / cm 3 Do the following:

[0408] 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.

[0409] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be provided.

[0410] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0411] (Embodiment 6) In this embodiment, an electronic device according to one aspect of the present invention will be described with reference to Figures 25 to 28.

[0412] 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.

[0413] 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.

[0414] Examples of electronic devices include television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, and other electronic devices with relatively large screens, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, and audio playback devices.

[0415] 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.

[0416] 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 high detail, it becomes possible to further enhance the sense of presence and depth in portable or personal-use electronic devices for home use.

[0417] 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.

[0418] 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.

[0419] The electronic device of this embodiment may have sensors (including those with functions to measure 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).

[0420] 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.

[0421] The electronic device 6500 shown in Figure 25A is a portable information terminal that can be used as a smartphone.

[0422] 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.

[0423] A display device according to one aspect of the present invention can be applied to the display unit 6502.

[0424] Figure 25B is a schematic cross-sectional view of the housing 6501, including the end on the microphone 6506 side.

[0425] 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, and battery 6518 are arranged in the space enclosed by the housing 6501 and the protective member 6510.

[0426] 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).

[0427] 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.

[0428] 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.

[0429] Figure 26A 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.

[0430] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0431] The television device 7100 shown in Figure 26A 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.

[0432] 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.

[0433] Figure 26B shows an example of a notebook personal computer. The notebook personal computer 7200 has a casing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214, etc. A display unit 7000 is incorporated into the casing 7211.

[0434] A display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0435] Figures 26C and 26D show examples of digital signage.

[0436] The digital signage 7300 shown in Figure 26C comprises a housing 7301, a display unit 7000, and a speaker 7303, etc. Furthermore, it may include LED lamps, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc.

[0437] Figure 26D 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.

[0438] In Figures 26C and 26D, a display device according to one embodiment of the present invention can be applied to the display unit 7000.

[0439] 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.

[0440] 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.

[0441] Furthermore, as shown in Figures 26C and 26D, 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.

[0442] 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.

[0443] Figure 27A shows the external appearance of the camera 8000 with the viewfinder 8100 attached.

[0444] The camera 8000 includes a housing 8001, a display unit 8002, operation buttons 8003, and a shutter button 8004, etc. A detachable lens 8006 is also attached to the camera 8000. The lens 8006 and the housing 8001 may be integrated into a single unit.

[0445] 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.

[0446] The housing 8001 has a mount with electrodes, and in addition to the viewfinder 8100, it can also be connected to, for example, a strobe device.

[0447] The viewfinder 8100 includes a housing 8101, a display unit 8102, and buttons 8103, etc.

[0448] The housing 8101 is attached to the camera 8000 by a mount that engages with the camera 8000's mount. The viewfinder 8100 can, for example, display the image received from the camera 8000 on the display unit 8102.

[0449] Button 8103 functions, for example, as a power button.

[0450] 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.

[0451] Figure 27B shows the external appearance of the head-mounted display 8200.

[0452] The head-mounted display 8200 includes a mounting section 8201, lenses 8202, a main unit 8203, a display unit 8204, and a cable 8205, among other components. The mounting section 8201 also has a built-in battery 8206.

[0453] Cable 8205 supplies power from battery 8206 to main unit 8203. Main unit 8203 is equipped with, for example, a wireless receiver and can display received video information on display unit 8204. Main unit 8203 is also equipped with a camera and can use information about the user's eyeball or eyelid movements as an input means.

[0454] Furthermore, the attachment portion 8201 may be equipped with multiple electrodes at a position that touches the user, capable of detecting the current flowing in accordance with the user's eye movements. This allows the head-mounted display 8200 to have a function of recognizing the user's gaze. The head-mounted display 8200 may also have a function of monitoring the user's pulse rate based on the current flowing through the electrodes. The attachment portion 8201 may also be equipped with various sensors such as a temperature sensor, a pressure sensor, or an acceleration sensor. The head-mounted display 8200 may also have a function of displaying the user's biometric information on the display unit 8204, or a function of changing the image displayed on the display unit 8204 in accordance with the user's head movements.

[0455] A display device according to one aspect of the present invention can be applied to the display unit 8204.

[0456] Figures 27C to 27E 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.

[0457] 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, it is possible to perform, for example, a three-dimensional display using parallax. Note that the configuration is not limited to having one display unit 8302; two display units 8302 may be provided, with one display unit for each of the user's eyes.

[0458] 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 27E, 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.

[0459] Figure 27F 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.

[0460] 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 square or a horizontally elongated rectangle. This can enhance the sense of realism.

[0461] 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 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.

[0462] 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, or sponge can be used. Furthermore, if the surface of a sponge or similar material is covered with cloth, leather (genuine leather or synthetic leather), etc., 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, in addition to being pleasant to the touch, it prevents the user from feeling cold when worn in cold seasons, for example. 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 facilitates cleaning or replacement.

[0463] The electronic equipment shown in Figures 28A to 28F 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.

[0464] The electronic devices shown in Figures 28A to 28F 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.

[0465] A display device according to one embodiment of the present invention can be applied to the display unit 9001.

[0466] The details of the electronic equipment shown in Figures 28A to 28F will be explained below.

[0467] Figure 28A 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, a connection terminal 9006, or a sensor 9007. The PDA 9101 can also display text and image information on multiple surfaces. Figure 28A shows an example where three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the subject of emails, SNS messages, etc., sender name, date and time, time, battery level, or signal strength. Alternatively, icons 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0468] Figure 28B 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.

[0469] Figure 28C 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.

[0470] Figures 28D to 28F are perspective views showing a foldable portable information terminal 9201. Figure 28D shows the portable information terminal 9201 in an unfolded state, Figure 28F shows it in a folded state, and Figure 28E shows a perspective view of the state in between, transitioning from one of Figures 28D or 28F to the other. 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 a hinge 9055. For example, the display unit 9001 can be bent with a radius of curvature of 0.1 mm to 150 mm.

[0471] 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. [Explanation of Symbols]

[0472] 100: Display device, 100A: Display device, 100B: Display device, 100C: Display device, 100D: Display device, 100E: Display device, 100F: Display device, 100G: Display device, 101: Layer, 103: Pixel, 103a: Sub-pixel, 103b: Sub-pixel, 103c: Sub-pixel, 110: Light-emitting element, 110B: Light-emitting element, 110G: Light-emitting element, 110R: Light-emitting element, 111: Pixel electrode, 111B: Pixel electrode, 111C: Connecting 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, 124a: pixel, 124b: pixel, 130: region, 131: protective layer, 131B: protective layer, 131Bf: protective film, 131G: protective layer, 131Gf: protective film, 131R: protective layer, 131Rf: protective film, 132: insulating layer, 132f: insulating film, 133: protective layer, 133a: protective layer, 133b: protective layer, 135: region, 143a: resist mask, 143b: resist mask, 143c: resist mask, 144Ba: sacrificial film, 144Bb: sacrificial film, 144G a: Sacrificial layer, 144Gb: Sacrificial layer, 144R: Sacrificial layer, 144Ra: Sacrificial layer, 144Rb: Sacrificial layer, 145: Sacrificial layer, 145a: Sacrificial layer, 145b: Sacrificial layer, 145Ba: Sacrificial layer, 145Bb: Sacrificial layer, 145G: Sacrificial layer, 145Ga: Sacrificial layer, 145Gb: Sacrificial layer, 145R: Sacrificial layer, 145Ra: Sacrificial layer, 145Rb: Sacrificial layer, 201: Transistor, 204: Connector, 205: Transistor, 209: Transistor, 210: Transistor, 211: Insulating layer, 213: Insulating layer, 214: Insulating layer, 215: Insulating layer, 218: Insulating layer, 221: Conductive layer, 222a: conductive layer, 222b: conductive layer, 223: conductive layer, 225: insulating layer, 228: region, 231: semiconductor layer, 231i: channel formation region, 231n: low resistance region, 240: capacitance, 241: conductive layer, 242: connection layer, 243: insulating layer, 245: conductive layer, 247B: conductive layer, 247G: conductive layer, 247R: conductive layer, 248: conductive layer, 249: slit, 251: conductive layer, 252: conductive layer, 253: insulating layer, 254: insulating layer, 255: insulating layer, 256: plug, 256B: plug, 256G: plug, 256R: plug, 257: insulating layer, 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, 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 Edge 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, 414: Insulating layer, 417: Light-shielding layer, 418B: Conductive layer, 418G: Conductive layer, 418R: Conductive layer, 419: Resin layer, 420: Substrate, 442: Adhesive layer, 443: Space, 451: Substrate, 452: Substrate, 462: Display unit, 464: Circuit, 465: Wiring, 466: Conductive layer, 468: 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, 6506: Microphone, 6507: Camera, 6508: Light source, 6510: Protective material, 6511: Display panel Nell, 6512: Optical components, 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, 7301: Enclosure, 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 part, 8202: Lens, 8203: Main unit, 8204: Display unit, 8205: Cable, 8206: Battery, 8300: Head-mounted display, 8301: Housing, 8302: Display unit, 8304: Fixing device, 830 5: 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 digital assistant, 9102: Personal digital assistant, 9200: Personal digital assistant, 9201: Personal digital assistant,

Claims

1. Having a display unit, The display unit comprises a first light-emitting element, a second light-emitting element arranged adjacent to the first light-emitting element, a third light-emitting element arranged adjacent to the second light-emitting element, first to sixth protective layers, and an insulating layer. The first light-emitting element described above has a structure in which a first pixel electrode, a first EL layer, a common layer, and a common electrode are stacked in this order. The second light-emitting element has a structure in which a second pixel electrode, a second EL layer, the common layer, and the common electrode are stacked in this order. The third light-emitting element has a structure in which a third pixel electrode, a third EL layer, the common layer, and the common electrode are stacked in this order. The first protective layer has a region that is in contact with the side surface of the first EL layer, The second protective layer has a region that is in contact with the side surface of the first protective layer, The third protective layer has a region that is in contact with the side surface of the second protective layer, The fourth protective layer has a region that is in contact with the side surface of the second EL layer, The fifth protective layer has a region that is in contact with the side surface of the fourth protective layer, The sixth protective layer has a region that is in contact with the side surface of the third EL layer, The insulating layer has a region that contacts the common layer, the third protective layer, and the fifth protective layer, and does not contact the first EL layer and the second EL layer, in a display device.

2. In Claim 1, The display unit further has seventh to twelfth protective layers, The seventh protective layer has a region that is in contact with the side surface of the first pixel electrode, The eighth protective layer has a region that is in contact with the side surface of the seventh protective layer, The ninth protective layer has a region that is in contact with the side surface of the eighth protective layer, The tenth protective layer has a region that is in contact with the side surface of the second pixel electrode, The 11th protective layer has a region that is in contact with the side surface of the 10th protective layer, The twelfth protective layer is a display device having a region in contact with the side surface of the eleventh protective layer.

3. In Claim 2, The insulating layer is a display device having a region in contact with the ninth protective layer and the twelfth protective layer.

4. In any one of claims 1 to 3, The insulating layer has regions that overlap with the upper surface of the first EL layer and the upper surface of the second EL layer in a cross-sectional view, A display device in which sacrificial layers are provided between the insulating layer and the first EL layer, and between the insulating layer and the second EL layer, respectively, in the aforementioned region.

5. In any one of claims 1 to 4, The insulating layer is a display device having a photosensitive resin.

6. In any one of claims 1 to 5, The common layer is a display device in which the first light-emitting element, the second light-emitting element, and the third light-emitting element include at least one of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, or an electron injection layer.

7. In any one of claims 1 to 6, A display device having a region in which the distance between the side surface of the first EL layer and the side surface of the second EL layer is 1 μm or less.

8. In claim 7, A display device having a region in which the distance between the side surface of the first EL layer and the side surface of the second EL layer is 100 nm or less.

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

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

Images