Indication device

Abstract

Provided is a display device having a high display quality. Provided is a highly reliable display device. Provided is a display device which has low power consumption and with which high definition can be achieved easily. Provided is a display device that combines a high display quality with high definition. Provided is a display device that has high contrast. This display device includes a first pixel, a second pixel disposed adjacent to the first pixel, and a first insulating layer, wherein: the first pixel includes a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer; the second pixel includes a second pixel electrode, a second EL layer on the second pixel electrode, and the common electrode on the second EL layer; a side surface of the first EL layer and a side surface of the second EL layer each have a region in contact with the first insulating layer; a side surface of the first pixel electrode is covered by the first EL layer; and a side surface of the second pixel electrode is covered by the second EL layer.

Description

[Technical Field]

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

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

[0003] In recent years, there has been a demand for higher definition display panels. Devices requiring high-definition display panels include, for example, smartphones, tablet devices, and notebook computers. Furthermore, with the rise in resolution, stationary display devices such as televisions and monitors also require higher definition. Furthermore, devices requiring the highest definition include, for example, devices for virtual reality (VR) or augmented reality (AR).

[0004] Representative examples of display devices that can be applied to display panels include liquid crystal display devices, organic EL (Electro Luminescence) elements, light-emitting devices equipped with light-emitting elements such as light-emitting diodes (LEDs: Light Emitting Diodes), and electronic paper that displays using electrophoresis methods.

[0005] For example, the basic structure of an organic EL element (organic electroluminescent element) is a layer containing a light-emitting organic compound sandwiched between a pair of electrodes. By applying a voltage between the pair of electrodes, light can be emitted from the light-emitting organic compound. A display device using such an organic EL element does not require a backlight, which is necessary in liquid crystal display devices and the like, and therefore can 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 disclosed in Patent Document 1.

[0006] Patent Document 2 discloses a display device for VR that uses an organic EL device. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-324673 [Patent Document 2] International Publication No. 2018 / 087625 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of one embodiment of the present invention is to provide a display device with high display quality.An object of one embodiment of the present invention is to provide a display device with high reliability.An object of one embodiment of the present invention is to provide a display device with low power consumption.An object of one embodiment of the present invention is to provide a display device that can easily be made high-definition.An object of one embodiment of the present invention is to provide a display device that has both high display quality and high definition.An object of one embodiment of the present invention is to provide a display device with high contrast.

[0009] An object of one embodiment of the present invention is to provide a display device having a novel structure or a manufacturing method of the display device.An object of one embodiment of the present invention is to provide a method for manufacturing the above-described display device with high yield.An object of one embodiment of the present invention is to alleviate at least one of the problems of the prior art.

[0010] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description of the specification, drawings, claims, etc. [Means for solving the problem]

[0011] One embodiment of the present invention is a display device having a first pixel, a second pixel arranged adjacent to the first pixel, and a first insulating layer, in which the first pixel has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer, and the second pixel has a second pixel electrode, a second EL layer on the second pixel electrode, and a common electrode on the second EL layer, and the side surfaces of the first EL layer and the second EL layer have regions in contact with the first insulating layer, and the side surfaces of the first pixel electrode are covered with the first EL layer, and the side surfaces of the second pixel electrode are covered with the second EL layer.

[0012] Alternatively, one embodiment of the present invention is a display device having a first pixel, a second pixel arranged adjacent to the first pixel, and a first insulating layer, in which the first pixel has a first pixel electrode, a first EL layer over the first pixel electrode, and a common electrode over the first EL layer, and the second pixel has a second pixel electrode, a second EL layer over the second pixel electrode, and a common electrode over the second EL layer, in which side surfaces of the first EL layer and the second EL layer have regions in contact with the first insulating layer, and an end of the first pixel electrode is located inside an end of the first EL layer, and an end of the second pixel electrode is located inside an end of the second EL layer.

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

[0014] In the above structure, the upper surface of the first EL layer, the upper surface of the second EL layer, and the upper surface of the first insulating layer preferably have regions in contact with the common electrode.

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

[0016] In the above structure, in a cross-sectional view of the display device, the first insulating layer preferably has a region that protrudes above at least one of the upper surface of the first EL layer and the upper surface of the second EL layer.

[0017] In the above structure, in a cross-sectional view of the display device, at least one of the first EL layer and the second EL layer preferably has a region that protrudes above the top surface of the first insulating layer.

[0018] In the above structure, the upper surface of the first insulating layer preferably has a concave curved shape in a cross-sectional view of the display device.

[0019] In the above structure, the upper surface of the first insulating layer preferably has a convex curved shape in a cross-sectional view of the display device.

[0020] Alternatively, one embodiment of the present invention is a display device including a first pixel, a second pixel arranged adjacent to the first pixel, a first insulating layer, and a second insulating layer, in which the first pixel has a first pixel electrode, a first EL layer over the first pixel electrode, and a common electrode over the first EL layer, the second pixel has a second pixel electrode, a second EL layer over the second pixel electrode, and a common electrode over the second EL layer, side surfaces of the first EL layer and the second EL layer have regions in contact with the first insulating layer, the second insulating layer is provided on and in contact with the first insulating layer and is disposed below the common electrode, the first insulating layer contains an inorganic material, and the second insulating layer contains an organic material, and the side surfaces of the first pixel electrode are covered with the first EL layer, and the side surfaces of the second pixel electrode are covered with the second EL layer.

[0021] In the above structure, the upper surface of the first EL layer, the upper surface of the second EL layer, and the upper surface of the first insulating layer preferably have regions in contact with the common electrode.

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

[0023] In the above structure, in a cross-sectional view of the display device, the first insulating layer preferably has a region that protrudes above at least one of the upper surface of the first EL layer and the upper surface of the second EL layer.

[0024] In the above structure, in a cross-sectional view of the display device, at least one of the first EL layer and the second EL layer preferably has a region that protrudes above the top surface of the first insulating layer.

[0025] In the above structure, the upper surface of the second insulating layer preferably has a concave curved shape in a cross-sectional view of the display device.

[0026] In the above structure, the upper surface of the second insulating layer preferably has a convex curved shape in a cross-sectional view of the display device. [Effects of the Invention]

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

[0028] According to one embodiment of the present invention, a display device having a novel structure or a manufacturing method of the display device can be provided. Also, a method for manufacturing the above-described display device with high yield can be provided. According to one embodiment of the present invention, at least one of the problems of the prior art can be alleviated.

[0029] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these can be extracted from the description in the specification, drawings, claims, etc. [Brief explanation of the drawings]

[0030] Fig. 1A is a top view showing an example of a display device, and Figs. 1B to 1D are cross-sectional views showing the example of the display device. 2A to 2C are cross-sectional views showing an example of a display device. 3A to 3C are cross-sectional views showing an example of a display device. 4A to 4F are cross-sectional views showing an example of a method for manufacturing a display device. 5A to 5D are cross-sectional views showing an example of a method for manufacturing a display device. 6A to 6C are cross-sectional views showing an example of a method for manufacturing a display device. 7A to 7C are cross-sectional views showing an example of a method for manufacturing a display device. 8A and 8B are cross-sectional views showing an example of a display device. 9A and 9B are cross-sectional views showing an example of a display device. FIG. 10 is a perspective view showing an example of a display device. 11A is a cross-sectional view showing an example of a display device, and FIGS. 11B and 11C are cross-sectional views showing an example of a transistor. 12A and 12B are perspective views showing an example of a display module. FIG. 13 is a cross-sectional view showing an example of a display device. FIG. 14 is a cross-sectional view showing an example of a display device. FIG. 15 is a cross-sectional view showing an example of a display device. FIG. 16 is a cross-sectional view showing an example of a display device. 17A to 17F are diagrams showing configuration examples of light-emitting elements. 18A and 18B are diagrams showing an example of an electronic device. 19A to 19D are diagrams showing an example of an electronic device. 20A to 20F are diagrams showing an example of an electronic device. 21A to 21F are diagrams showing an example of an electronic device. 22A and 22B are photographs showing the display panel according to the embodiment. 23A to 23C show the results of spectrum measurement according to the example. 24A to 24C show the results of spectrum measurement according to the example. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments will be described with reference to the drawings. However, it will be readily understood by those skilled in the art that the embodiments can be implemented in many different ways and that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the following description of the embodiments.

[0032] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted. In addition, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be assigned.

[0033] In the drawings described in this specification, the size of each component, the thickness of a layer, or an area may be exaggerated for clarity, and therefore, the drawings are not necessarily limited to the scale.

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

[0035] In this specification, ordinal numbers such as "first" and "second" are used to avoid confusion of components and do not limit the number.

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

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

[0038] In this specification and the like, a display panel, which is one aspect of a display device, has a function of displaying (outputting) images etc. on a display surface, and therefore the display panel is one aspect of an output device.

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

[0040] A light-emitting element of one embodiment of the present invention may include a layer containing a substance with a high hole-injection property, a substance with a high hole-transport property, a substance with a high electron-transport property, a substance with a high electron-injection property, a bipolar substance, or the like.

[0041] The light-emitting layer and the layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a substance with high electron-transport properties, a substance with high electron-injection properties, a bipolar substance, or the like may each contain an inorganic compound such as quantum dots or a polymer compound (oligomer, dendrimer, polymer, or the like). For example, quantum dots can be used in the light-emitting layer to function as a light-emitting material.

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

[0043] In this specification, etc., a device fabricated using a metal mask or FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. Also, in this specification, etc., a device fabricated without using a metal mask or FMM may be referred to as a device with an MML (metal maskless) structure.

[0044] In this specification, a structure in which different light-emitting layers are formed or different light-emitting layers are painted for each color light-emitting device (here, blue (B), green (G), and red (R)) may be referred to as an SBS (Side By Side) structure. In this specification, a light-emitting device that can emit white light may be referred to as a white light-emitting device. A white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0045] Light-emitting devices can be broadly divided into single-structure and tandem-structure devices. A single-structure device has one light-emitting unit between a pair of electrodes, and the light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, two or more light-emitting layers may be selected so that the light emitted from each of the two or more light-emitting layers has a complementary color relationship. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary, a configuration in which the entire light-emitting device emits white light can be obtained. The same applies to light-emitting devices having three or more light-emitting layers.

[0046] A tandem-structured device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. To obtain white light, light from the light-emitting layers of the multiple light-emitting units may be combined to obtain white light. The configuration for obtaining white light is the same as that of the single-structured device. In a tandem-structured device, it is preferable to provide an intermediate layer such as a charge-generating layer between the multiple light-emitting units.

[0047] Furthermore, when comparing the above-mentioned white light-emitting device (single structure or tandem structure) with a light-emitting device having an SBS structure, the light-emitting device having an SBS structure can reduce power consumption compared to the white light-emitting device. If you want to keep power consumption low, it is preferable to use a light-emitting device having an SBS structure. On the other hand, the manufacturing process of a white light-emitting device is simpler than that of a light-emitting device having an SBS structure, so it is preferable because it can reduce manufacturing costs or increase manufacturing yields.

[0048] (Embodiment 1) In this embodiment, a structural example of a display device according to one embodiment of the present invention and an example of a manufacturing method of the display device will be described.

[0049] One embodiment of the present invention is a display device having a light-emitting element (also referred to as a light-emitting device). The display device has at least two light-emitting elements that emit light of different colors. Each light-emitting element has a pair of electrodes and an EL layer therebetween. An electroluminescent element such as an organic EL element or an inorganic EL element can be used as the light-emitting element. Alternatively, a light-emitting diode (LED) can be used. The light-emitting element of one embodiment of the present invention is preferably an organic EL element. Two or more light-emitting elements that emit different colors each have an EL layer containing a different material. For example, a full-color display device can be realized by having three types of light-emitting elements that emit red (R), green (G), or blue (B) light, respectively.

[0050] Here, when creating separate EL layers for light-emitting elements of different colors, it is known to form them by vapor deposition using a shadow mask such as a metal mask. However, this method can lead to deviations in the shape and position of the island-shaped organic film from the design due to various factors, such as the accuracy of the metal mask, misalignment between the metal mask and the substrate, metal mask deflection, and the spread of the contours of the deposited film due to vapor scattering, making it difficult to achieve high resolution and a high aperture ratio. Furthermore, during vapor deposition, debris can be generated due to material adhering to the metal mask. This debris can cause pattern defects in the light-emitting elements. Furthermore, the debris can cause short circuits. Furthermore, a process of cleaning the material adhering to the metal mask is required. Therefore, measures have been taken to artificially increase the resolution (also known as pixel density) by applying special pixel arrangements such as a pentile array.

[0051] In one embodiment of the present invention, an EL layer is processed 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 definition and a large aperture ratio, which have been difficult to achieve until now. Furthermore, because the EL layer can be individually fabricated, a display device with extremely vivid, high contrast, and high display quality can be realized.

[0052] For simplicity, we will explain the case where EL layers for two color light-emitting elements are formed separately. First, a first EL film and a first sacrificial film are laminated to cover the pixel electrodes. Next, a resist mask is formed on the first sacrificial film. Next, using the resist mask, a portion of the first sacrificial film and a portion of the first EL film are etched to form the first EL layer and the first sacrificial layer on the first EL layer.

[0053] Next, a second EL film and a second sacrificial film are laminated. Then, a resist mask is used to etch a portion of the second sacrificial film and a portion of the second EL film to form a second EL layer and a second sacrificial layer on the second EL layer. Next, the pixel electrodes are processed using the first sacrificial layer and the second sacrificial layer as masks to form a first pixel electrode overlapping the first EL layer and a second pixel electrode overlapping the second EL layer. In this way, the first EL layer and the second EL layer can be separately fabricated. Finally, the first sacrificial layer and the second sacrificial layer are removed, and a common electrode is formed, thereby fabricating two-color light-emitting elements.

[0054] Furthermore, by repeating the above process, it is possible to separately fabricate EL layers for light-emitting elements of three or more colors, thereby realizing a display device having light-emitting elements of three or more colors.

[0055] At the edge of the EL layer, a step occurs between the area where the pixel electrode and the EL layer are provided and the area where the pixel electrode and the EL layer are not provided. When forming a common electrode on the EL layer, the step at the edge of the EL layer may reduce the coverage of the common electrode, which may lead to the common electrode being cut off. In addition, the common electrode may become thinner, which may increase its electrical resistance.

[0056] Furthermore, when the edge of the pixel electrode is roughly aligned with the edge of the EL layer, or when the edge of the pixel electrode is located outside the edge of the EL layer, the common electrode and the pixel electrode may short-circuit when the common electrode is formed on the EL layer.

[0057] In one embodiment of the present invention, by providing an insulating layer between the first EL layer and the second EL layer, the unevenness of the surface on which the common electrode is provided can be reduced. Therefore, coverage of the edge of the first EL layer and the edge of the second EL layer with the common electrode can be improved, and good conductivity of the common electrode can be achieved. In addition, short-circuiting between the common electrode and the pixel electrode can be suppressed.

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

[0059] Furthermore, the pattern of the EL layer itself can be made much smaller than when a metal mask is used. For example, when a metal mask is used to separately create an EL layer, thickness variations occur between the center and edges of the pattern, resulting in a smaller effective area that can be used as the light-emitting region relative to the overall area of ​​the pattern. In contrast, the above-described fabrication method forms a pattern by processing a film deposited to a uniform thickness, making it possible to achieve a uniform thickness within the pattern, and even with a fine pattern, almost the entire area can be used as the light-emitting region. Therefore, the above-described fabrication method can achieve both high definition and a high aperture ratio.

[0060] In this way, according to the above-described manufacturing method, a display device integrating minute light-emitting elements can be realized, and therefore there is no need to artificially increase the resolution by applying a special pixel arrangement method such as a pen tile method. Therefore, it is possible to realize a display device with a so-called stripe arrangement in which R, G, and B are each arranged in one direction, and with a resolution of 500 ppi or more, 1000 ppi or more, 2000 ppi or more, or even 3000 ppi or more, or even 5000 ppi or more.

[0061] Below, a more specific example of a structure and an example of a manufacturing method of a display device of one embodiment of the present invention will be described with reference to the drawings.

[0062] [Configuration example 1] 1A is a schematic top view of a display device 100 according to one embodiment of the present invention. The display device 100 includes a plurality of red light-emitting elements 110R, a plurality of green light-emitting elements 110G, and a plurality of blue light-emitting elements 110B. In FIG. 1A, the light-emitting regions of the light-emitting elements are labeled with R, G, and B to easily distinguish the light-emitting elements from one another.

[0063] The light-emitting elements 110R, 110G, and 110B are arranged in a matrix. The pixel 103 shown in Fig. 1A has a so-called stripe arrangement in which light-emitting elements of the same color are arranged in one direction. The arrangement of the light-emitting elements is not limited to this, and other arrangements such as a delta arrangement or a zigzag arrangement may also be used, or a pentile arrangement may also be used.

[0064] It is preferable to use EL elements such as OLEDs (organic light emitting diodes) or QLEDs (quantum-dot light emitting diodes) as the light emitting elements 110R, 110G, and 110B. Examples of light emitting materials that the EL elements have include fluorescent materials, phosphorescent materials, inorganic compounds (quantum dot materials, etc.), and materials that exhibit thermally activated delayed fluorescence (thermally activated delayed fluorescence: TADF materials).

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

[0066] FIG. 1B shows cross sections of the light-emitting elements 110R, 110G, and 110B. In FIG. 1B, the light-emitting elements 110R, 110G, and 110B are provided on a substrate 101. The light-emitting element 110R has a pixel electrode 111R, an EL layer 112R, a common layer 114, and a common electrode 113. The light-emitting element 110G has a pixel electrode 111G, an EL layer 112G, a common layer 114, and a common electrode 113. The light-emitting element 110B has a pixel electrode 111B, an EL layer 112B, a common layer 114, and a common electrode 113. An insulating layer 131 is provided between adjacent light-emitting elements. Note that, hereinafter, when describing matters common to the pixel electrodes 111R, 111G, and 111B, the symbols added to the reference numerals may be omitted and the pixel electrodes may be referred to as pixel electrodes 111. Furthermore, when describing matters common to the EL layer 112R, the EL layer 112G, and the EL layer 112B, the symbols added to the reference numerals may be omitted and the description may be made by referring to the EL layer 112. Furthermore, hereinafter, when describing matters common to the light-emitting element 110R, the light-emitting element 110G, and the light-emitting element 110B, the symbols added to the reference numerals may be omitted and the description may be made by referring to the light-emitting element 110.

[0067] Figure 2A shows an enlarged view of the area enclosed by the dashed-dotted rectangular line in Figure 1B, and Figure 2B shows an enlarged view of the area enclosed by the dashed-dotted rectangular line in Figure 1C.

[0068] In this specification and the like, in drawings before enlargement, the thicknesses of layers and films may be depicted thicker for clarity. Furthermore, in drawings after enlargement, the distances between the components of the display device may differ. For example, in FIG. 2A and the like, the distance between the end of the pixel electrode 111R and the end of the EL layer 112R, and the distance between the end of the pixel electrode 111B and the end of the EL layer 112B are depicted broadly. Furthermore, the spacing between the components of the light-emitting element 110B and the components of the light-emitting element 110R is depicted broadly.

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

[0070] 1B and 1C, the common layer 114 is provided between the pixel electrode 111 and the common electrode 113 of the light-emitting element 110. The common layer is provided as a continuous layer common to each light-emitting element. Note that the light-emitting element 110 may not have the common layer 114.

[0071] 1A also shows a connection electrode 111C that is electrically connected to the common electrode 113. The connection electrode 111C is given a potential (for example, an anode potential or a cathode potential) to be supplied to the common electrode 113. The connection electrode 111C is provided outside the display area where the light-emitting elements 110R and the like are arranged. Also, in FIG. 1A, the common electrode 113 is shown by a dashed line.

[0072] The connection electrodes 111C can be provided along the periphery of the display area. For example, they may be provided along one side of the periphery of the display area, or along two or more sides of the periphery of the display area. That is, when the top surface of the display area has a rectangular shape, the top surface of the connection electrodes 111C can have a strip shape, an L-shape, a U-shape (square bracket shape), a square shape, or the like.

[0073] 1B also shows a cross section corresponding to the dashed dotted line C1-C2 shown in FIG. 1A. In the cross section shown in C1-C2, a region 130 is provided where the connection electrode 111C and the common electrode 113 are electrically connected. While FIG. 1B shows an example in which a common layer 114 is provided between the connection electrode 111C and the common electrode 113, as shown in FIG. 1D, the common layer 114 may not be provided in the region 130. In FIG. 1D, the connection electrode 111C and the common electrode 113 can be configured to be in contact with each other, thereby further reducing contact resistance.

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

[0075] The EL layer 112R, the EL layer 112G, and the EL layer 112B each have a layer (light-emitting layer) containing a light-emitting organic compound. The light-emitting layer may contain one or more compounds (host material, assist material) in addition to a light-emitting substance (guest material). As the host material and the assist material, one or more substances having an energy gap larger than the energy gap of the light-emitting substance (guest material) can be selected and used. As the host material and the assist material, it is preferable to use a combination of compounds that form an exciplex. In order to efficiently form an exciplex, it is particularly preferable to combine a compound that easily accepts holes (hole-transporting material) with a compound that easily accepts electrons (electron-transporting material).

[0076] The light-emitting element can be made of either a low molecular weight compound or a high molecular weight compound, and may contain an inorganic compound (such as a quantum dot material).

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

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

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

[0080] Alternatively, a conductive film that transmits visible light can be used as the pixel electrode 111 over a conductive film that reflects visible light. Examples of conductive materials that transmit 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, and indium zinc oxide containing silicon. Alternatively, an oxide of a conductive material that reflects visible light can be used, and the oxide may be formed by oxidizing the surface of a conductive material that reflects visible light. Specifically, for example, titanium oxide may be used. Titanium oxide may be formed, for example, by oxidizing the surface of titanium.

[0081] By providing an oxide on the surface of the pixel electrode 111, oxidation reaction with the pixel electrode 111 can be suppressed when the EL layer 112 is formed.

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

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

[0084] In light-emitting devices, by varying the optical path length using a microcavity structure (a microresonator structure), it is possible to intensify light of a specific wavelength, thereby realizing a display device with improved color purity.

[0085] For example, a microcavity structure can be realized by varying the thickness of the EL layer 112 in each light-emitting element. For example, the EL layer 112R of the light-emitting element 110R that emits light with the longest wavelength can be configured to be the thickest, and the EL layer 112B of the light-emitting element 110B that emits light with the shortest wavelength can be configured to be the thinnest. However, this is not limitative, and the thickness of each EL layer can be adjusted taking into consideration the wavelength of light emitted by each light-emitting element, the optical characteristics of the layers that make up the light-emitting element, and the electrical characteristics of the light-emitting element.

[0086] The upper surface and edges of the pixel electrode 111 are covered with the EL layer 112. The edges of the EL layer 112 are preferably positioned outside the edges of the pixel electrode 111.

[0087] Since the EL layer 112 covers the upper surface and end portion of the pixel electrode 111, the steps of forming the EL layer 112, the insulating layer 131, etc. can be performed without exposing the pixel electrode 111.

[0088] If the edge of the pixel electrode 111 is exposed during the etching process for forming the EL layer 112 or the insulating layer 131, corrosion may occur in the exposed area. The products generated by the corrosion of the pixel electrode 111 may be unstable, and there is a concern that they may dissolve in the solution in wet etching or scatter into the atmosphere in dry etching. When the products dissolve in the solution or scatter into the atmosphere, they may adhere to the side surfaces of the EL layer 112 and the surface of the substrate 101, for example, and may form leak paths between adjacent light-emitting elements 110.

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

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

[0091] An insulating layer 131 is provided between adjacent light emitting elements 110. The insulating layer 131 is located between the EL layers 112 of the light emitting elements 110. In addition, a common electrode 113 is provided on the insulating layer 131.

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

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

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

[0095] By providing the insulating layer 131 between the light-emitting elements of different colors, the EL layer 112R, the EL layer 112G, and the EL layer 112G can be prevented from contacting each other. This effectively prevents current from flowing through two adjacent EL layers, which would otherwise cause unintended light emission. This improves contrast, enabling the realization of a display device with high display quality.

[0096] The insulating layer 131 has an insulating layer 131a and an insulating layer 131b. The insulating layer 131b is provided so as to be in contact with the side surface of each EL layer 112 of the light-emitting element 110. In addition, in a cross-sectional view, the insulating layer 131a is provided on and in contact with the insulating layer 131b so as to fill the recessed portion of the insulating layer 131b.

[0097] In FIG. 1, the insulating layer 131 is disposed between the EL layers 112 of adjacent pixels so as to have a mesh-like (or lattice-like or matrix-like) shape when viewed from above.

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

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

[0100] The edge of the EL layer 112 preferably has a region in contact with the insulating layer 131b.

[0101] By providing the insulating layer 131 between the light-emitting elements of different colors, the EL layer 112R, the EL layer 112G, and the EL layer 112G can be prevented from contacting each other. This effectively prevents current from flowing through two adjacent EL layers, which would otherwise cause unintended light emission. This improves contrast, enabling the realization of a display device with high display quality.

[0102] Note that the insulating layer 131 may not be provided between adjacent pixels of the same color, and may be formed only between pixels of different colors. In this case, the insulating layer 131 may have a striped shape when viewed from above. By forming the insulating layer 131 in a striped shape, the space required for forming the insulating layer 131 is eliminated compared to when the insulating layer 131 has a grid shape, and therefore the aperture ratio can be increased. When the insulating layer 131 is formed in a striped shape, adjacent EL layers of the same color may be processed into stripes so that they are continuous in the column direction.

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

[0104] Between adjacent light-emitting elements, a step occurs at the edge of the EL layer 112 due to a region where the EL layer 112 is provided and a region where the EL layer 112 is not provided. In the display device of one embodiment of the present invention, the insulating layers 131a and 131b are provided to planarize the step, and the coverage of the common electrode 113 can be improved compared to when the common electrode 113 is provided between adjacent light-emitting elements in contact with the substrate 101. This can suppress connection defects due to disconnection of the step. Alternatively, the step can suppress an increase in electrical resistance due to a local thinning of the common electrode 113.

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

[0106] In order to improve the flatness of the surface on which the common electrode 113 is formed, it is preferable that the upper surfaces of the insulating layers 131a and 131b roughly coincide with the upper surface of the EL layer 112 at the ends of the EL layer 112. It is also preferable that the upper surface of the insulating layer 131 has a flat shape. However, the upper surfaces of the insulating layers 131a and 131b and the upper surface of the EL layer 112 do not necessarily have to coincide. Furthermore, when the heights of the upper surfaces of the EL layers 112 corresponding to different colors are different, it is preferable that the height of the upper surface of the insulating layer 131a roughly coincides with the height of the upper surface of each EL layer in the vicinity of each EL layer. It is also preferable that the height of the upper surface of the insulating layer 131b roughly coincides with the height of each EL layer in the region in contact with the side surface of each EL layer.

[0107] 2A and other figures, the height of the upper surface of insulating layer 131a is approximately the same as the height of the upper surface of EL layer 112B in the vicinity of EL layer 112B, and is approximately the same as the height of the upper surface of EL layer 112R in the vicinity of EL layer 112R. Furthermore, the height of the upper surface of insulating layer 131b is approximately the same as the height of the upper surface of EL layer 112B in the region in contact with the side surface of EL layer 112B, and is approximately the same as the height of the upper surface of EL layer 112R in the region in contact with the side surface of EL layer 112R.

[0108] 2C shows an example in which the shape of the insulating layer 131a is different from that of the insulating layer 131a shown in FIG.

[0109] 3A and 3B show examples in which the shape of insulating layer 131a etc. is different from that of Figures 2A and 2B. In Figures 3A and 3B, the top surface of insulating layer 131a has a recessed shape in the center and its vicinity.

[0110] Fig. 3C shows an example in which the shape of insulating layer 131a etc. is different from that of Fig. 2B. In Fig. 3C, the upper surface of insulating layer 131a has a shape in which the center and its vicinity bulge.

[0111] The insulating layer 131b has a region in contact with the side surface of the EL layer 112 and functions as a protective insulating layer for the EL layer 112. By providing the insulating layer 131b, it is possible to prevent oxygen, moisture, or their constituent elements from entering the inside from the side surface of the EL layer 112, thereby making it possible to provide a highly reliable display device.

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

[0113] The insulating layer 131b can be an insulating layer containing an inorganic material. The insulating layer 131b can be formed using a single layer or a stack of aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon oxide, silicon oxynitride, silicon nitride, silicon nitride oxide, or the like. Aluminum oxide is particularly preferable because it has a high etching selectivity with respect to the EL layer 112 and protects the EL layer 112 during the formation of the insulating layer 131b, which will be described later. By using an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by an ALD method, the insulating layer 131b can have fewer pinholes and can have an excellent function of protecting the EL layer 112.

[0114] In this specification, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0115] The insulating layer 131b can be formed by sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), atomic layer deposition (ALD), etc. The insulating layer 131b can be preferably formed by ALD, which has good coverage.

[0116] The insulating layer 131a provided on the insulating layer 131b has the function of planarizing recesses formed in the insulating layer 131b between adjacent light-emitting elements. In other words, the insulating layer 131a has the effect of improving the flatness of the surface on which the common electrode 113 is formed. An insulating layer containing an organic material can be suitably used as the insulating layer 131a. For example, acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenolic resin, and precursors of these resins can be used as the insulating layer 131a. Furthermore, a photosensitive resin can be used as the insulating layer 131a. The photosensitive resin can be a positive-type material or a negative-type material.

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

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

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

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

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

[0122] The common layer 114, like the common electrode 113, is provided across a plurality of light-emitting elements. The common layer 114 is provided to cover the EL layer 112R, the EL layer 112G, and the EL layer 112B. The structure including the common layer 114 simplifies the manufacturing process, thereby reducing manufacturing costs. The common layer 114 and the common electrode 113 can be formed consecutively without an intervening process such as etching. Therefore, the interface between the common layer 114 and the common electrode can be made clean, and good characteristics can be obtained in the light-emitting element.

[0123] Preferably, EL layer 112R, EL layer 112G, and EL layer 112B each have a light-emitting layer containing a light-emitting material that emits light of at least one color. Furthermore, common layer 114 is preferably a layer that includes one or more of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. In a light-emitting element in which the pixel electrode serves as the anode and the common electrode serves as the cathode, common layer 114 may include an electron injection layer or both an electron injection layer and an electron transport layer.

[0124] [Production method example 1] An example of a method for manufacturing a display device according to one embodiment of the present invention will be described below with reference to the drawings. Here, the display device 100 shown in the above configuration example will be described as an example. FIGS. 4A to 7C are schematic cross-sectional views illustrating steps in the manufacturing method of the display device described below.

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

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

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

[0128] There are two typical photolithography methods: one is to form a resist mask on the thin film to be processed, process the thin film by etching or the like, and then remove the resist mask; the other is to form a photosensitive thin film, and then process the thin film into the desired shape by exposure and development.

[0129] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. Other light sources that can be used include ultraviolet light, KrF laser light, and ArF laser light. Exposure can also be performed using immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays can also be used as the light used for exposure. Instead of light used for exposure, an electron beam can also be used. Extreme ultraviolet light, X-rays, or an electron beam are preferred because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0130] For etching the thin film, dry etching, wet etching, sandblasting, or the like can be used.

[0131] [Preparation of Substrate 101] A substrate having heat resistance sufficient to withstand at least a subsequent heat treatment can be used as the substrate 101. When an insulating substrate is used as the substrate 101, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, an organic resin substrate, or the like can be used. Also, a semiconductor substrate such as a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, or an SOI substrate can be used.

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

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

[0134] When a conductive film reflective to visible light is used as the pixel electrode, it is preferable to use a material (such as silver or aluminum) with as high a reflectance as possible over the entire wavelength range of visible light, which not only increases the light extraction efficiency of the light-emitting element but also improves color reproducibility.

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

[0136] The EL film 112Rf includes a film containing at least a light-emitting compound. Alternatively, the EL film 112Rf may include one or more layers functioning as an electron injection layer, an electron transport layer, a charge generation layer, a hole transport layer, or a hole injection layer. The EL film 112Rf can be formed by, for example, a vapor deposition method, a sputtering method, or an inkjet method. However, the method is not limited to these, and the above-described film formation methods can be used as appropriate.

[0137] [Formation of Sacrificial Film 144(1)R and Sacrificial Film 144(2)R] Next, the process of forming the sacrificial film will be described.

[0138] The sacrificial film 144R is a film that will become the sacrificial layer 145R. The sacrificial film 144G is a film that will become the sacrificial layer 145G. The sacrificial film 144B is a film that will become the sacrificial layer 145B. The sacrificial layers 145R, 145G, and 145B may be collectively referred to as the sacrificial layer 145. The sacrificial layer 145 may have a single layer structure or a laminated structure of two or more layers.

[0139] An example using a two-layer sacrificial layer will be described below.

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

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

[0142] In the sacrificial film formation process, first, a sacrificial film 144(1)R is formed to cover the EL film 112Rf. The sacrificial film 144(1)R is also provided in contact with the upper surface of the connection electrode 111C. Next, a sacrificial film 144(2)R is formed on the sacrificial film 144(1)R.

[0143] The sacrificial film 144(1)R and the sacrificial film 144(2)R can be formed by, for example, sputtering, ALD (thermal ALD, PEALD), or vacuum deposition. Note that a formation method that causes less damage to the EL layer is preferable, and for the sacrificial film 144(1)R formed directly on the EL film 112Rf, it is preferable to form the sacrificial film 144(1)R using the ALD or vacuum deposition method rather than the sputtering method.

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

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

[0146] The sacrificial film 144(1)R may be made of a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, or tantalum, or an alloy material containing such a metal material. In particular, it is preferable to use a low-melting-point material such as aluminum or silver.

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

[0148] The present invention can also be applied to a case where, instead of the gallium, an element M (wherein M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) is used. In particular, it is preferable that M is one or more elements selected from gallium, aluminum, and yttrium.

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

[0150] The sacrificial film 144(1)R can be a film that is highly resistant to the etching process of each EL film such as the EL film 112Rf, i.e., a film with a large etching selectivity. Furthermore, it is particularly preferable to use a film that can be removed by wet etching, which causes little damage to each EL film, for the sacrificial film 144(1)R.

[0151] Furthermore, the sacrificial film 144(1)R may be made of a material that is soluble in a chemically stable solvent, at least for the film located at the top of the EL film 112Rf. Materials that dissolve in water or alcohol are particularly suitable for use as the sacrificial film 144(1)R. When forming the sacrificial film 144(1)R, it is preferable to apply the sacrificial film 144(1)R dissolved in a solvent such as water or alcohol using a wet film-forming method, and then perform a heat treatment to evaporate the solvent. Performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to the EL film 112Rf.

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

[0153] The sacrificial film 144(1)R can be made of an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin.

[0154] The sacrificial film 144(2)R may be a film having a large selectivity with respect to the sacrificial film 144(1)R.

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

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

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

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

[0159] The resist mask 143a can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

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

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

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

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

[0164] By etching the sacrificial film 144(1)R using the sacrificial layer 145(2)R as a hard mask, the resist mask 143a can be removed in a state where the EL film 112Rf is covered with the sacrificial film 144(1)R. In particular, if the EL film 112Rf comes into contact with oxygen, it may have an adverse effect on the electrical characteristics, so this is suitable for etching using oxygen gas, such as plasma ashing.

[0165] Next, the sacrificial film 144(1)R is removed by etching using the sacrificial layer 145(2)R as a mask, to form an island-shaped or strip-shaped sacrificial layer 145(1)R. Note that in the method for manufacturing a display device of one embodiment of the present invention, either the sacrificial layer 145(1)R or the sacrificial layer 145(2)R may be omitted.

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

[0167] The EL film 112Rf is preferably etched using dry etching with an etching gas that does not contain oxygen as a main component. This prevents deterioration of the EL film 112Rf and realizes a highly reliable display device. Examples of etching gases that do not contain oxygen as a main component include noble gases such as CF4, C4F8, SF6, CHF3, Cl2, HO, BCl3, and He. A mixed gas of any of the above gases and a dilution gas that does not contain oxygen can also be used as the etching gas. Here, a portion of the sacrificial layer 145(1)R may be removed during etching of the EL film 112Rf. For example, if the sacrificial film 144(1)R has a two-layer structure, with the lower layer made of an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by the ALD method and the upper layer made of a metal oxide containing indium, such as indium gallium zinc oxide (In-Ga-Zn oxide, also referred to as IGZO) formed by the sputtering method, the upper layer may be etched during etching of the EL film 112Rf.

[0168] The etching of the EL film 112Rf is not limited to the above, and may be dry etching using other gases or wet etching.

[0169] Furthermore, the etching rate can be increased by using an etching gas containing oxygen gas or dry etching using oxygen gas to etch the EL film 112Rf. Therefore, etching can be performed under low power conditions while maintaining a sufficiently high etching rate, thereby reducing damage caused by etching. Furthermore, problems such as adhesion of reaction products generated during etching can be suppressed. For example, an etching gas obtained by adding oxygen gas to the above-mentioned etching gas that does not contain oxygen as a main component can be used.

[0170] [Formation of EL Layer 112G and EL Layer 112B] Subsequently, an EL film 112Gf that will become the EL layer 112G is formed on the sacrificial layer 145(1)R, the pixel electrode 111G, and the pixel electrode 111B. For the EL film 112Gf, the description of the EL film 112Rf can be referred to.

[0171] Subsequently, a sacrificial film 144(1)G is formed on the EL film 112Gf. For the sacrificial film 144(1)G, the description of the sacrificial film 144(1)R can be referred to.

[0172] Subsequently, a sacrificial film 144(2)G is formed on the sacrificial film 144(1)G. For the sacrificial film 144(2)G, the description of the sacrificial film 144(2)R can be referred to.

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

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

[0175] Subsequently, an EL film 112Bf that will become the EL layer 112B is formed on the sacrificial layer 145(2)R, the sacrificial layer 145(2)G, and the pixel electrode 111B. For the EL film 112Bf, the description of the EL film 112Rf can be referred to.

[0176] Subsequently, a sacrificial film 144(1)B is formed on the EL film 112Bf. For the sacrificial film 144(1)B, the description of the sacrificial film 144(1)R can be referred to.

[0177] Subsequently, a sacrificial film 144(2)B is formed on the sacrificial film 144(1)B. For the sacrificial film 144(2)B, the description of the sacrificial film 144(2)R can be referred to.

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

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

[0180] FIG. 4F shows an enlarged view of the area enclosed by the dashed dotted square line in FIG. 4E.

[0181] In this specification and the like, in drawings before enlargement, the thicknesses of layers and films may be depicted thicker for clarity. Furthermore, in drawings after enlargement, the distance between each component of the display device may differ. For example, in FIG. 4F, the distance between the end of the pixel electrode 111 and the end of the EL layer 112 is depicted as being wider. Furthermore, the distance between the components of the light-emitting element 110B and the components of the light-emitting element 110R is depicted as being wider.

[0182] Next, sacrificial layer 145(2)R, sacrificial layer 145(2)G, and sacrificial layer 145(2)B (hereinafter collectively referred to as sacrificial layer 145(2)) are removed by etching or the like (FIG. 5A). When etching sacrificial layer 145(2), it is preferable to use conditions that provide a high selectivity with respect to sacrificial layer 145(1)R, sacrificial layer 145(1)G, and sacrificial layer 145(1)B (hereinafter collectively referred to as sacrificial layer 145(1)). It is also possible not to remove sacrificial layer 145(2).

[0183] [Formation of insulating layer 131] Next, an insulating film 131bf that becomes the insulating layer 131b is formed (FIG. 5B). The insulating film 131bf is preferably a film containing an inorganic material. For example, a single layer or a stacked layer of a film containing aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon oxide, silicon oxynitride, silicon nitride, silicon nitride oxide, or the like can be used.

[0184] The insulating film 131bf can be formed by sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), atomic layer deposition (ALD), etc. The insulating film 131bf can be preferably formed by ALD, which has good coverage.

[0185] The insulating film 131bf can be formed using a single layer or a stack of aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon oxide, silicon oxynitride, silicon nitride, silicon nitride oxide, or the like. Aluminum oxide is particularly preferable because it has a high etching selectivity with respect to the EL layer 112 and has a function of protecting the EL layer 112 in the formation of the insulating layer 131b, which will be described later.

[0186] By forming the insulating film 131bf by the ALD method, it is possible to obtain a film with few pinholes, and the insulating layer 131b can have an excellent function of protecting the EL layer 112.

[0187] The insulating film 131bf is preferably formed at a temperature lower than the heat-resistant temperature of the EL layer 112.

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

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

[0190] The insulating film 131af is preferably an insulating film containing an organic material, and the organic material is preferably a resin.

[0191] Examples of materials that can be used for the insulating film 131af include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. The insulating film 131af can be formed using a photosensitive resin. The photosensitive resin can be a positive or negative material.

[0192] By forming the insulating film 131af using a photosensitive resin, the insulating film 131af can be produced by only exposure and development processes, which reduces damage to the layers constituting the light-emitting element 110, particularly the EL layer.

[0193] The insulating film 131af may have gentle unevenness reflecting the unevenness of the surface on which it is formed, as shown in Fig. 5C. Alternatively, the insulating film 131af may be less affected by the unevenness of the surface on which it is formed, as shown in Fig. 5D, and may be flatter than the insulating film 131af shown in Fig. 5C.

[0194] Next, the insulating layer 131a is formed. Here, by using a photosensitive resin as the insulating film 131af, the insulating layer 131a can be formed without providing an etching mask such as a resist mask or a hard mask. Furthermore, since the photosensitive resin can be processed only by the steps of exposure and development, the insulating layer 131a can be formed without using a dry etching method or the like. This simplifies the process. Furthermore, damage to the EL layer due to etching of the insulating film 131af can be reduced. Note that the surface height may be adjusted by further etching a portion of the upper part of the insulating layer 131a.

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

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

[0197] An example of a method for forming the insulating layer 131a will be described with reference to Figures 6A to 6C. Figure 6A shows an example in which a photosensitive resin is used as the insulating film 131af, and the insulating film 131af is processed using exposure and development processes to form the insulating layer 131ap. Figure 6B is an enlarged view of the area surrounded by the dashed dotted line in Figure 6A. The insulating layer 131ap shown in Figure 6B can be further etched to form the insulating layer 131a shown in Figure 6C.

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

[0199] Next, the insulating film 131bf and the sacrificial layer 145(1) are etched (FIG. 7A). At this time, it is preferable to use a method that causes as little damage as possible to the EL layers 112R, 112G, and 112B. As a result, the insulating layer 131b is formed, covering the side surfaces of the EL layers 112R, 112G, and 112B. FIG. 7B is an enlarged view of the area surrounded by the dashed dotted square line in FIG. 7A.

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

[0201] The insulating film 131bf can be etched by dry etching or wet etching. Alternatively, etching may be performed by ashing using oxygen plasma. Alternatively, chemical mechanical polishing (CMP) may be used to etch the insulating film 131bf.

[0202] When etching the insulating film 131bf, it is preferable to suppress damage caused by etching to the EL layer 112. Therefore, for example, it is preferable to use a material having a high etching selectivity with respect to the EL layer 112 as the insulating film 131bf.

[0203] Using an inorganic material for the insulating film 131bf can sometimes increase the selectivity with respect to the EL layer 112. Furthermore, the insulating layer 131b can be formed using a single layer or a stack of aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon oxide, silicon oxynitride, silicon nitride, silicon nitride oxide, or the like. Aluminum oxide is particularly preferable because it has a high etching selectivity with respect to the EL layer 112 and protects the EL layer 112 during the formation of the insulating layer 131b, which will be described later. In particular, using an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide formed by an ALD method for the insulating layer 131b can result in a film with fewer pinholes and an excellent function of protecting the EL layer 112.

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

[0205] The surface flatness of the insulating film 131af containing an organic material may vary depending on the unevenness of the surface on which it is formed and the density of the pattern formed on the surface. Furthermore, the flatness of the insulating film 131af may vary depending on the viscosity of the material used for the insulating film 131af. For example, the thickness of the insulating film 131af in a region that does not overlap with the EL layer 112 may be smaller than the thickness of the insulating film 131af in a region that overlaps with the EL layer 112. In such a case, for example, by etching back the insulating film 131af, the height of the upper surface of the insulating layer 131 may become lower than the height of the upper surface of the sacrificial layer 145(1).

[0206] Furthermore, the insulating film 131af may have a shape having a concave curved surface (a recessed shape) or a shape having a convex curved surface (a bulging shape) in the region between the plurality of EL layers 112.

[0207] [Formation of common layer 114] Next, the common layer 114 is formed. In the case where the common layer 114 is not provided, the common electrode 113 may be formed to cover the EL layer 112R, the EL layer 112G, and the EL layer 112B.

[0208] [Formation of Common Electrode 113] Next, the common electrode 113 is formed on the common layer 114. The common electrode 113 can be formed by, for example, sputtering or vacuum deposition. In a configuration in which the common layer 114 is not provided on the connection electrode 111C, a metal mask that shields the connection electrode 111C may be used in forming the common layer 114. The metal mask used in this case does not need to shield the pixel region of the display unit, so there is no need to use a high-resolution mask.

[0209] Through the above steps, the light emitting elements 110R, 110G, and 110B can be fabricated.

[0210] [Formation of protective layer 121] Next, a protective layer 121 is formed on the common electrode 113 (FIG. 7C). The inorganic insulating film used for the protective layer 121 is preferably formed by sputtering, PECVD, or ALD. The ALD method is particularly preferred because it has excellent step coverage and is less likely to cause defects such as pinholes. The inkjet method is also preferred for forming the organic insulating film because it can form a uniform film in the desired area.

[0211] Through the above steps, the display device 100 shown in FIG. 1A can be fabricated.

[0212] [Modification of Configuration Example 1] 8A and 8B show modified examples of the configuration of the display device 100 shown in FIG.

[0213] Display device 100 shown in Fig. 8A differs from that shown in Fig. 1B in the shapes of insulating layers 131a, 131b, etc. Fig. 8B shows an enlarged view of the area surrounded by a dashed dotted square line in Fig. 8A.

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

[0215] 9A and 9B are different from FIG. 8B in the shapes of the insulating layer 131a, insulating layer 131b, etc.

[0216] 9A can be obtained by using the insulating layer 131ap shown in FIG. 6B as the insulating layer 131a. For example, the insulating layer 131a may be provided so that the upper surface of the insulating layer 131a is higher than the upper surface of the light-emitting layer of the EL layer 112.

[0217] 9B shows an example in which there is no step at the end of the EL layer 112. By using the configuration shown in Fig. 9B, the distance between the EL layers 112 of different light-emitting elements 110 can be reduced, and the aperture ratio of the light-emitting elements 110 can be increased in some cases.

[0218] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0219] (Embodiment 2) In this embodiment, a structural example of a display device according to one embodiment of the present invention will be described.

[0220] The display device of the present embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of the present embodiment can be used in electronic devices having relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, smartphones, wristwatch-type terminals, tablet terminals, personal digital assistants, and sound reproducing devices.

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

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

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

[0224] The circuit 464 can be, for example, a scanning line driver circuit.

[0225] The wiring 465 has a function of supplying signals and power to the display portion 462 and the circuit 464. The signals and power are input to the wiring 465 from the outside via the FPC 472 or from the IC 473.

[0226] 10 shows an example in which an IC 473 is provided on a substrate 451 by a COG (Chip On Glass) method or a COF (Chip On Film) method. The IC 473 may be, for example, an IC having a scanning line driver circuit or a signal line driver circuit. The display device 400A and the display module may not include an IC. Alternatively, the IC may be mounted on an FPC by a COF method or the like.

[0227] FIG. 11A shows an example of a cross section of display device 400A, where a part of the region including FPC 472, a part of circuit 464, a part of display unit 462, and a part of the region including the end portion are cut away.

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

[0229] The light-emitting element described in Embodiment 1 can be applied to the light-emitting element 430a, the light-emitting element 430b, and the light-emitting element 430c.

[0230] Here, when a pixel of a display device has three types of subpixels having light-emitting elements that emit different colors, the three subpixels include subpixels of three colors of red (R), green (G), and blue (B), or subpixels of three colors of yellow (Y), cyan (C), and magenta (M), etc. When a pixel of a display device has four subpixels, the four subpixels include subpixels of four colors of red (R), green (G), blue (B), and white (W), or subpixels of four colors of R, G, B, and Y, etc.

[0231] The protective layer 410 and the substrate 452 are bonded via an adhesive layer 442. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light-emitting element. In FIG. 11A, a space 443 surrounded by the substrate 452, the adhesive layer 442, and the substrate 451 is filled with an inert gas (such as nitrogen or argon), and a hollow sealing structure is applied. The adhesive layer 442 may be provided so as to overlap the light-emitting element. Furthermore, the space 443 surrounded by the substrate 452, the adhesive layer 442, and the substrate 451 may be filled with a resin different from the adhesive layer 442.

[0232] In an opening provided in the insulating layer 214 so as to expose the top surface of the conductive layer 222b of the transistor 205, parts of the conductive layer 418a, the conductive layer 418b, and the conductive layer 418c are formed along the bottom and side surfaces of the opening. The conductive layer 418a, the conductive layer 418b, and the conductive layer 418c are each connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The pixel electrode contains a material that reflects visible light, and the counter electrode contains a material that transmits visible light. Other parts of the conductive layer 418a, the conductive layer 418b, and the conductive layer 418c are provided over the insulating layer 214.

[0233] A pixel electrode 411a, a pixel electrode 411b, and a pixel electrode 411c are provided over the conductive layer 418a, the conductive layer 418b, and the conductive layer 418c. An insulating layer 414 may be provided between the conductive layer 418a and the conductive layer 411a of the light-emitting element 430a, between the conductive layer 418b and the conductive layer 411b of the light-emitting element 430b, and between the conductive layer 418c and the conductive layer 411c of the light-emitting element 430c.

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

[0235] The pixel electrode 111 shown in the above embodiment can be applied to the pixel electrode 411a, the pixel electrode 411b, and the pixel electrode 411c.

[0236] An insulating layer 421 is provided in a region between the light-emitting element 430a and the light-emitting element 430b over the insulating layer 214, and in a region between the light-emitting element 430b and the light-emitting element 430c over the insulating layer 214. The insulating layer 131 described in the above embodiment can be referred to for the insulating layer 421.

[0237] Light emitted from the light-emitting element is emitted toward the substrate 452. The substrate 452 is preferably made of a material that is highly transparent to visible light.

[0238] The transistor 201 and the transistor 205 are both formed over a substrate 451. These transistors can be manufactured using the same material and through the same process.

[0239] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 451 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 is provided to cover the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0240] At least one insulating layer covering the transistor is preferably made of a material that is resistant to the diffusion of impurities such as water and hydrogen. This allows the insulating layer to function as a barrier layer. With this structure, it is possible to effectively prevent impurities from diffusing into the transistor from the outside, thereby improving the reliability of the display device.

[0241] It is preferable to use an inorganic insulating film for each of the insulating layers 211, 213, and 215. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. Alternatively, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may also be used. Two or more of the above insulating films may be stacked.

[0242] Here, organic insulating films often have lower barrier properties than inorganic insulating films. Therefore, it is preferable that the organic insulating film has an opening near the edge of the display device 400A. This can prevent impurities from entering from the edge of the display device 400A through the organic insulating film. Alternatively, the organic insulating film may be formed so that the edge of the organic insulating film is located inside the edge of the display device 400A, so that the organic insulating film is not exposed at the edge of the display device 400A.

[0243] An organic insulating film is suitable for the insulating layer 214, which functions as a planarizing layer. Materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0244] 11A, an opening is formed in a two-layer laminate structure of insulating layer 214 and insulating layer 421b on insulating layer 214. Insulating layer 421b can be formed using the same material as insulating layer 421. In addition, insulating layer 421b is formed, for example, using the same process as insulating layer 421. Protective layer 410 is formed so as to cover the opening. By using an inorganic layer as protective layer 410, it is possible to prevent impurities from entering display unit 462 from the outside through insulating layer 214, even when insulating layer 214 is an organic insulating film. This can improve the reliability of display device 400A.

[0245] The transistor 201 and the transistor 205 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a conductive layer 222a functioning as one of a source and a drain, a conductive layer 222b functioning as the other of the source and drain, a semiconductor layer 231, an insulating layer 213 functioning as a gate insulating layer, and a conductive layer 223 functioning as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0246] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Furthermore, either a top-gate transistor or a bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0247] The transistor 201 and the transistor 205 have a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates may be connected and the same signal may be supplied to drive the transistor. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential for controlling the threshold voltage to one of the two gates and a potential for driving to the other.

[0248] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0249] The semiconductor layer of the transistor preferably contains metal oxide (also referred to as an oxide semiconductor). That is, the display device of this embodiment preferably uses a transistor using metal oxide in a channel formation region (hereinafter referred to as an OS transistor). Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystal silicon).

[0250] The semiconductor layer preferably contains, for example, indium, M (wherein M is one or more elements selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more elements selected from aluminum, gallium, yttrium, and tin.

[0251] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) as the semiconductor layer.

[0252] When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. Examples of atomic ratios of metal elements in such In-M-Zn oxides include compositions in which In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:1:1.2 or thereabouts, In:M:Zn=2:1:3 or thereabouts, In:M:Zn=3:1:2 or thereabouts, In:M:Zn=4:2:3 or thereabouts, In:M:Zn=4:2:4.1 or thereabouts, In:M:Zn=5:1:3 or thereabouts, In:M:Zn=5:1:6 or thereabouts, In:M:Zn=5:1:7 or thereabouts, In:M:Zn=5:1:8 or thereabouts, In:M:Zn=6:1:6 or thereabouts, and In:M:Zn=5:2:5 or thereabouts, etc. Note that "nearby compositions" includes a range of ±30% of the desired atomic ratio.

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

[0254] The transistors included in the circuit 464 may have the same structure as or different from the transistors included in the display portion 462. The transistors included in the circuit 464 may all have the same structure or may have two or more types of structures. Similarly, the transistors included in the display portion 462 may all have the same structure or may have two or more types of structures.

[0255] A connection portion 204 is provided in an area of ​​the substrate 451 where the substrate 452 does not overlap. In the connection portion 204, a wiring 465 is electrically connected to the FPC 472 via a conductive layer 466 and a connection layer 242. The conductive layer 466 can be a conductive film obtained by processing the same conductive film as the pixel electrodes, or a conductive film 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. The conductive layer 466 is exposed on the upper surface of the connection portion 204. This allows the connection portion 204 and the FPC 472 to be electrically connected via the connection layer 242.

[0256] It is preferable to provide a light-shielding layer 417 on the surface of substrate 452 facing substrate 451. In addition, various optical members can be arranged on the outside of substrate 452. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light-collecting film. In addition, an antistatic film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses the occurrence of scratches during use, an impact absorbing layer, etc. may be arranged on the outside of substrate 452.

[0257] By providing the protective layer 410 that covers the light-emitting element, impurities such as water can be prevented from entering the light-emitting element, and the reliability of the light-emitting element can be improved.

[0258] In a region 228 near the edge of the display device 400A, it is preferable that the insulating layer 215 and the protective layer 410 contact each other through the 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 410 contact each other. This makes it possible to prevent impurities from entering the display unit 462 from the outside through the organic insulating film. This can therefore improve the reliability of the display device 400A.

[0259] The substrate 451 and the substrate 452 can each be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, or the like. A material that transmits light is used for the substrate on the side from which light from the light-emitting element is extracted. Using a flexible material for the substrate 451 and the substrate 452 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used for the substrate 451 or the substrate 452.

[0260] Substrate 451 and substrate 452 can be made of polyester resin such as polyethylene terephthalate (PET) or 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, polyamideimide 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 having a thickness sufficient to provide flexibility.

[0261] When a circularly polarizing plate is superimposed on a display device, it is preferable that the display device has a substrate with high optical isotropy. A substrate with high optical isotropy has small birefringence (or a small amount of birefringence).

[0262] The absolute value of the retardation (phase difference) of a substrate having high optical isotropy is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0263] Examples of films with high optical isotropy include triacetyl cellulose (TAC, also known as cellulose triacetate) films, cycloolefin polymer (COP) films, cycloolefin copolymer (COC) films, and acrylic films.

[0264] Furthermore, when a film is used as a substrate, the film may absorb water, causing deformation such as wrinkles 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 preferably 0.1% or less, and even more preferably 0.01% or less.

[0265] The adhesive layer can be made of various curable adhesives, such as photo-curable adhesives (e.g., ultraviolet curable), reactive curable adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. Materials with low moisture permeability, such as epoxy resin, are particularly preferred. Two-component resins may also be used. Adhesive sheets, etc., may also be used.

[0266] The connection layer 242 may be made of an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0267] Materials that can be used for conductive layers such as the gate, source, and drain of a transistor, as well as various wirings and electrodes that constitute a display device include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, and alloys containing these metals as main components, etc. Films containing these materials can be used as a single layer or a stacked layer structure.

[0268] Examples of light-transmitting conductive materials include conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium, or graphene. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metal materials, can be used. Alternatively, nitrides of such metal materials (e.g., titanium nitride) can be used. When using metal materials or alloy materials (or their nitrides), it is preferable to thin them sufficiently to ensure light-transmitting properties. A stacked film of the above materials can also be used as the conductive layer. For example, a stacked film of an alloy of silver and magnesium and indium tin oxide is preferable because it can enhance conductivity. These can also be used for conductive layers such as various wirings and electrodes constituting a display device, and for conductive layers (conductive layers functioning as pixel electrodes or common electrodes) of light-emitting elements.

[0269] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0270] The transistor 201 and the transistor 205 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a semiconductor layer including 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 functioning as a gate insulating layer, a conductive layer 223 functioning as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel formation region 231i. The insulating layer 225 is located between the conductive layer 223 and the channel formation region 231i.

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

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

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

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

[0275] By using silicon transistors such as LTPS transistors, circuits that need to be driven at high frequencies (such as source driver circuits) can be built on the same substrate as the display unit, which simplifies the external circuits mounted on the display device and reduces component and mounting costs.

[0276] At least one of the transistors included in the pixel circuit preferably uses a transistor (hereinafter also referred to as an OS transistor) having a metal oxide (hereinafter also referred to as an oxide semiconductor) as a semiconductor in which a channel is formed. The OS transistor has significantly higher field-effect mobility than an amorphous silicon transistor. Furthermore, the OS transistor has a significantly smaller source-drain leakage current in an off state (hereinafter also referred to as an off-state current), and can retain charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of an OS transistor can reduce the power consumption of a display device.

[0277] By using LTPS transistors for some of the transistors included in a pixel circuit and OS transistors for the other transistors, a display device with low power consumption and high driving capability can be realized. A configuration in which an LTPS transistor and an OS transistor are combined is sometimes referred to as LTPO. As a more preferred example, it is preferable to use an OS transistor as a transistor that functions as a switch for controlling conduction / non-conduction between wirings and an LTPS transistor as a transistor for controlling current.

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

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

[0280] In this manner, one embodiment of the present invention can provide a display device that has a high aperture ratio, high definition, high display quality, and low power consumption.

[0281] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

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

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

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

[0285] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display unit 281. The display unit 281 is a region that displays an image in the display module 280, and is a region where light from each pixel provided in a pixel unit 284 (described later) can be viewed.

[0286] 12B is a perspective view schematically showing the configuration on the substrate 291 side. 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 on the substrate 291. A terminal section 285 for connecting to an FPC 290 is provided in a 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 composed of a plurality of wirings.

[0287] The pixel portion 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of FIG. 12B. The pixel 284a has light-emitting elements 430a, 430b, and 430c that emit light of different colors. The plurality of light-emitting elements are preferably arranged in a stripe array as shown in FIG. 12B. The stripe array allows pixel circuits containing light-emitting elements of one embodiment of the present invention to be arranged at high density, thereby providing a high-resolution display device. Various arrangement methods, such as a delta array and a pentile array, can also be used.

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

[0289] One pixel circuit 283a is a circuit that controls the light emission of three light-emitting elements included in one pixel 284a. One pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting element. For example, the pixel circuit 283a may be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitance element for each light-emitting element. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain. This realizes an active matrix display device.

[0290] The circuit portion 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like.

[0291] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit section 282. An IC may also be mounted on the FPC 290.

[0292] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are stacked below the pixel unit 284, thereby enabling the aperture ratio (effective display area ratio) of the display unit 281 to be extremely high. For example, the aperture ratio of the display unit 281 can be set to 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. Furthermore, the pixels 284a can be arranged at an extremely high density, enabling the resolution of the display unit 281 to be extremely high. For example, it is preferable that the pixels 284a are arranged in the display unit 281 at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20000 ppi or less, or 30000 ppi or less.

[0293] Such a display module 280 has extremely high resolution and can therefore be suitably used in VR devices such as head-mounted displays or eyeglass-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display unit 281, so that even if the display unit is enlarged with the lenses, the 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 having relatively small display units. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

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

[0295] The transistor 310 has a channel formation region in a substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part 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 in which the substrate 301 is doped with impurities and functions as either a source or a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311 and functions as an insulating layer.

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

[0297] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided on the insulating layer 261 .

[0298] Capacitor 240 has conductive layer 241, conductive layer 245, and insulating layer 243 positioned therebetween. Conductive layer 241 functions as one electrode of capacitor 240, conductive layer 245 functions as the other electrode of capacitor 240, and insulating layer 243 functions as a dielectric of capacitor 240.

[0299] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain of the transistor 310 by a plug 271 buried in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

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

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

[0302] [Display device 400D] 14 differs from display device 400C mainly in the configuration of the transistors, and a description of the same parts as display device 400C may be omitted.

[0303] The transistor 320 is a transistor in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

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

[0305] 12A and 12B. The substrate 331 may be an insulating substrate or a semiconductor substrate.

[0306] An insulating layer 332 is provided over a substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320 and prevents oxygen from being released from the semiconductor layer 321 toward the insulating layer 332. The insulating layer 332 can be, for example, a film through which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0307] A conductive layer 327 is provided over the insulating layer 332, and an insulating layer 326 is provided to cover the conductive layer 327. The conductive layer 327 functions as a first gate electrode of the transistor 320, and part of the insulating layer 326 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a portion of the insulating layer 326 that is in contact with the semiconductor layer 321. The top surface of the insulating layer 326 is preferably planarized.

[0308] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide (also referred to as an oxide semiconductor) film having semiconductor properties. Materials that can be suitably used for the semiconductor layer 321 will be described in detail later.

[0309] A pair of conductive layers 325 is provided over and in contact with the semiconductor layer 321 and functions as a source electrode and a drain electrode.

[0310] An insulating layer 328 is provided to cover top surfaces and side surfaces of the pair of conductive layers 325 and side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided over the insulating layer 328. The insulating layer 328 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 264 or the like to the semiconductor layer 321 and prevents oxygen from being released from the semiconductor layer 321. The insulating layer 328 can be an insulating film similar to the insulating layer 332.

[0311] An opening reaching the semiconductor layer 321 is provided in the insulating layer 328 and the insulating layer 264. An insulating layer 323 and a conductive layer 324 are buried inside the opening and are in contact with the side surfaces of the insulating layer 264, the insulating layer 328, and the conductive layer 325 and the top surface of the semiconductor layer 321. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0312] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0313] The insulating layer 264 and the insulating layer 265 function as interlayer insulating layers. The insulating layer 329 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 265 or the like to the transistor 320. The insulating layer 329 can be formed using an insulating film similar to the insulating layer 328 and the insulating layer 332.

[0314] A plug 274 electrically connected to one of the pair of conductive layers 325 is provided to be embedded in the insulating layer 265, the insulating layer 329, and the insulating layer 264. Here, the plug 274 preferably includes a conductive layer 274a covering the side surfaces of the openings in the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328 and part of the top surface of the conductive layer 325, and a conductive layer 274b in contact with the top surface of the conductive layer 274a. In this case, the conductive layer 274a is preferably made of a conductive material through which hydrogen and oxygen do not easily diffuse.

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

[0316] [Display device 400E] A display device 400E shown in FIG. 15 has a stacked structure of a transistor 310A and a transistor 310B, each of which has a channel formed in a semiconductor substrate.

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

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

[0319] By bonding the conductive layer 341 and the conductive layer 342, the substrate 301A and the substrate 301B are electrically connected.

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

[0321] [Display device 400F] 16 has a stacked structure of a transistor 310 having a channel formed in a substrate 301 and a transistor 320 having a channel formed in a semiconductor layer containing a metal oxide. Note that descriptions of parts similar to those of the display devices 400C and 400D may be omitted.

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

[0323] The transistor 320 can be used as a transistor included in a pixel circuit. The transistor 310 can be used as a transistor included in a pixel circuit or a driver circuit (gate line driver circuit, source line driver circuit) for driving the pixel circuit. The transistors 310 and 320 can be used as transistors included in various circuits such as an arithmetic circuit or a memory circuit.

[0324] With this configuration, not only pixel circuits but also driver circuits and the like can be formed directly under the light-emitting elements, making it possible to miniaturize the display device compared to when driver circuits are provided around the periphery of the display area.

[0325] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0326] (Fourth embodiment) In this embodiment, a light-emitting element (also referred to as a light-emitting device) that can be used for a display device that is one embodiment of the present invention will be described.

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

[0328] A structure having the layer 4420, the light-emitting layer 4411, and the layer 4430 provided between a pair of electrodes can function as a single light-emitting unit, and the structure of FIG. 17A is referred to as a single structure in this specification.

[0329] 17B shows a modified example of the EL layer 786 of the light-emitting device shown in Fig. 17A. Specifically, the light-emitting device shown in Fig. 17B has a layer 4430-1 on the lower electrode 772, a layer 4430-2 on the layer 4430-1, a light-emitting layer 4411 on the layer 4430-2, a layer 4420-1 on the light-emitting layer 4411, a layer 4420-2 on the layer 4420-1, and an upper electrode 788 on the layer 4420-2. For example, when the lower electrode 772 is an anode and the upper electrode 788 is a cathode, the layer 4430-1 functions as a hole injection layer, the layer 4430-2 functions as a hole transport layer, the layer 4420-1 functions as an electron transport layer, and the layer 4420-2 functions as an electron injection layer. Alternatively, when the lower electrode 772 is used as a cathode and the upper electrode 788 is used as an anode, the layer 4430-1 functions as an electron injection layer, the layer 4430-2 functions as an electron transport layer, the layer 4420-1 functions as a hole transport layer, and the 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 in the light-emitting layer 4411.

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

[0331] 17E and 17F, a configuration in which a plurality of light-emitting units (EL layer 786a, EL layer 786b) are connected in series via an intermediate layer (charge generating layer) 4440 is referred to as a tandem structure in this specification. Note that, although the configuration shown in FIGS. 17E and 17F is referred to as a tandem structure in this specification and the like, it is not limited thereto, and for example, the tandem structure may also be referred to as a stack structure. Note that by using a tandem structure, a light-emitting device capable of emitting light with high brightness can be obtained.

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

[0333] Different light-emitting materials may be used for the light-emitting layer 4411, the light-emitting layer 4412, and the light-emitting layer 4413. When the light emitted from the light-emitting layer 4411, the light-emitting layer 4412, and the light-emitting layer 4413 has a complementary color relationship, white light can be obtained. Figure 17D shows an example in which a colored layer 785 that functions as a color filter is provided. When white light passes through the color filter, light of a desired color can be obtained.

[0334] 17E, the same light-emitting material may be used for the light-emitting layer 4411 and the light-emitting layer 4412. Alternatively, light-emitting materials that emit light of different colors may be used for 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 is obtained. FIG. 17F shows an example in which a colored layer 785 is further provided.

[0335] 17C, 17D, 17E, and 17F, the layer 4420 and the layer 4430 may have a laminated structure made up of two or more layers, as shown in FIG. 17B.

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

[0337] The light-emitting device can emit light of red, green, blue, cyan, magenta, yellow, or white, depending on the material of the EL layer 786. The color purity can be further improved by providing the light-emitting device with a microcavity structure.

[0338] A light-emitting device that emits white light preferably has a configuration in which the light-emitting layer contains two or more types of light-emitting materials. 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 light-emitting materials has a complementary color relationship. For example, by making the color of the light emitted by the first light-emitting layer and the color of the light emitted by the second light-emitting layer complementary, a light-emitting device that emits white light as a whole can be obtained. The same applies to light-emitting devices having three or more light-emitting layers.

[0339] The light-emitting layer preferably contains two or more light-emitting materials that emit light of R (red), G (green), B (blue), Y (yellow), O (orange), etc. Alternatively, it is preferable that the light-emitting layer contains two or more light-emitting materials, and the light emitted by each of the light-emitting materials contains spectral components of two or more colors of R, G, and B.

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

[0341] The light-emitting device has at least a light-emitting layer. The light-emitting device may further have, in addition to the light-emitting layer, a layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a hole-blocking material, a substance with high electron-transport properties, an electron-blocking material, a substance with high electron-injection properties, or a bipolar substance (a substance with high electron-transport properties and high hole-transport properties).

[0342] The light-emitting device can be made of either a low-molecular-weight compound or a high-molecular-weight compound, and may contain an inorganic compound. The layers constituting the light-emitting device can be formed by a method such as vapor deposition (including vacuum vapor deposition), transfer, printing, inkjet printing, or coating.

[0343] For example, the light-emitting device may have a configuration including, in addition to a light-emitting layer, one or more layers selected from the group consisting of a hole-injection layer, a hole-transport layer, a hole-blocking layer, an electron-blocking layer, an electron-transport layer, and an electron-injection layer.

[0344] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a material with high hole injection properties, such as an aromatic amine compound and a composite material containing a hole transport material and an acceptor material (electron acceptor material).

[0345] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light emitting layer. The hole transport layer is a layer that contains a hole transporting material. Examples of the hole transporting material include 10 -6 cm 2A material having a hole mobility of 1 / Vs or more is preferred. Note that other materials can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, a material having a high hole transporting property, such as a π-electron-rich heteroaromatic compound (e.g., a carbazole derivative, a thiophene derivative, a furan derivative, etc.) or an aromatic amine (a compound having an aromatic amine skeleton), is preferred.

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

[0347] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a material with high electron injection properties. Examples of the material with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the material with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0348] Examples of the electron injection layer include lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatolithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviation: LiPPP), and lithium oxide (LiO x ), alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used.

[0349] Alternatively, the electron injection layer may be formed using a material having electron transport properties. For example, a compound having an unshared electron pair and an electron-deficient heteroaromatic ring may be used as the material having electron transport properties. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), and a triazine ring may be used.

[0350] The organic compound having an unshared electron pair preferably has a lowest unoccupied molecular orbital (LUMO) of -3.6 eV to -2.3 eV. Generally, the highest occupied molecular orbital (HOMO) level and the LUMO level of an organic compound can be estimated by cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, or the like.

[0351] Examples of organic compounds with lone electron pairs include 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz). NBPhen has a higher glass transition temperature (Tg) and better heat resistance than BPhen.

[0352] The light-emitting layer is a layer containing a light-emitting substance. The light-emitting layer can contain one or more light-emitting substances. As the light-emitting substance, a substance that emits light of a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red is appropriately used. Furthermore, a substance that emits near-infrared light can also be used as the light-emitting substance.

[0353] Examples of light-emitting materials include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0354] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0355] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, a pyrazine skeleton, or a pyridine skeleton; organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand; platinum complexes; and rare earth metal complexes.

[0356] The light-emitting layer may contain one or more organic compounds (host materials, assist materials, etc.) in addition to a light-emitting substance (guest material). One or more organic compounds may be a hole-transporting material or an electron-transporting material, or both. Alternatively, a bipolar material or a TADF material may be used as the one or more organic compounds.

[0357] The light-emitting layer preferably contains, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material that are a combination that easily forms an exciplex. This configuration allows for efficient emission using Exciplex-Triplet Energy Transfer (ExTET), which is energy transfer from the exciplex to the light-emitting material (phosphorescent material). By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material, the energy transfer becomes smooth, allowing for efficient emission. This configuration simultaneously enables high efficiency, low-voltage operation, and long life of the light-emitting device.

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

[0359] (Embodiment 5) In this embodiment, a metal oxide (also referred to as an oxide semiconductor) that can be used for the OS transistor described in the above embodiment will be described.

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

[0361] Furthermore, the metal oxide can be formed by a sputtering method, a chemical vapor deposition (CVD) method such as a metal organic chemical vapor deposition (MOCVD) method, or an atomic layer deposition (ALD) method.

[0362] <Classification of crystal structures> Examples of the crystalline structure of oxide semiconductors include amorphous (including completely amorphous), c-axis-aligned crystalline (CAAC), nanocrystalline (nc), cloud-aligned composite (CAC), single crystal, and polycrystal.

[0363] The crystalline structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectra. For example, it can be evaluated using XRD spectra obtained by GIXD (Grazing-Incidence XRD) measurements. The GIXD method is also called the thin film method or the Seemann-Bohlin method.

[0364] For example, for a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, for an IGZO film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical peak shape of the XRD spectrum clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0365] The crystalline structure of a film or substrate can also be evaluated by the diffraction pattern (also called the nanobeam electron diffraction pattern) observed using nanobeam 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. Furthermore, a spot-like pattern is observed in the diffraction pattern of an IGZO film deposited at room temperature, rather than a halo. For this reason, it is estimated that an IGZO film deposited at room temperature is neither crystalline nor amorphous, but is in an intermediate state, and it cannot be concluded that it is in an amorphous state.

[0366] <<Oxide semiconductor structure>> Note that oxide semiconductors may be classified differently from the above when focusing on their structures. For example, oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0367] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0368] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, each with its c-axis aligned in a specific direction. The specific direction can be 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 the atomic arrangement is considered as a lattice arrangement, a crystalline region can also be a region with a uniform lattice arrangement. Furthermore, CAAC-OS has a region where multiple crystalline regions are connected in the ab-plane direction, and the region may have distortion. Note that distortion refers to a location where the lattice arrangement changes between a region with a uniform lattice arrangement and a region with a different uniform lattice arrangement in the region where multiple crystalline regions are connected. In other words, CAAC-OS is an oxide semiconductor with a c-axis aligned but no clear orientation in the ab-plane direction.

[0369] Each of the multiple 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 the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of the crystalline region may be several tens of nm.

[0370] In an In-M-Zn oxide (wherein M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), the CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium (In) and oxygen (hereinafter referred to as an In layer) and a layer containing M, zinc (Zn), and oxygen (hereinafter referred to as an (M, Zn) layer) are stacked. Note that indium and the element M are mutually substituted. Therefore, the (M, Zn) layer may contain indium. The In layer may contain M. The In layer may contain Zn. The layered structure is observed as a lattice image in a high-resolution transmission electron microscope (TEM) image, for example.

[0371] When the CAAC-OS film is subjected to structural analysis using, for example, an XRD apparatus, a peak indicating c-axis orientation is detected at or near 2θ=31° in out-of-plane XRD measurement using θ / 2θ scan. Note that the position of the peak indicating c-axis orientation (2θ value) may vary depending on the type and composition of the metallic elements constituting the CAAC-OS.

[0372] For example, in the electron diffraction pattern of a CAAC-OS film, multiple bright spots are observed, and the spots are observed at positions that are point-symmetric with respect to the spot of the incident electron beam that has passed through the sample (also called the direct spot).

[0373] When the crystalline region is observed from the specific direction, the lattice arrangement within the crystalline region is basically a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the distortion may have a pentagonal, heptagonal, or other lattice arrangement. In CAAC-OS, no clear grain boundaries are observed even near the distortion. This indicates that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is thought to be because the CAAC-OS can tolerate distortion due to the lack of close-packed oxygen atom arrangement in the ab-plane direction and the change in interatomic bond distance caused by metal atom substitution.

[0374] A crystal structure with clear grain boundaries is called polycrystalline. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in the on-state current and field-effect mobility of a transistor. Therefore, CAAC-OS, which lacks clear grain boundaries, is one of the crystalline oxides with a crystal structure suitable for use in the semiconductor layer of a transistor. Zn is preferred for use in CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are suitable because they can suppress the generation of grain boundaries more effectively than In oxide.

[0375] CAAC-OS is an oxide semiconductor with high crystallinity and no clear grain boundaries. Therefore, it can be said that the decrease in electron mobility due to grain boundaries is unlikely to occur in CAAC-OS. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by the inclusion of impurities or the generation of defects, CAAC-OS can also be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Therefore, oxide semiconductors with CAAC-OS have stable physical properties. Therefore, oxide semiconductors with CAAC-OS are heat-resistant and highly reliable. Furthermore, CAAC-OS is stable even under high temperatures (so-called thermal budgets) during the manufacturing process. Therefore, using CAAC-OS for an OS transistor can increase the flexibility of the manufacturing process.

[0376] [nc-OS] The nc-OS has periodic atomic arrangement in a microscopic region (e.g., a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has microcrystalline structures. The size of these microcrystalline structures is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore these microcrystalline structures are also called nanocrystalline structures. Furthermore, the nc-OS exhibits no regularity in the crystal orientation between different nanocrystalline structures. Therefore, the entire film lacks orientation. Therefore, depending on the analytical method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor. For example, when a structural analysis of an nc-OS film is performed using an XRD system, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Furthermore, when electron diffraction (also known as selected-area electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of nanocrystalline structures (e.g., 50 nm or larger), a halo-like diffraction 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 nanocrystals (for example, 1 nm to 30 nm), an electron diffraction pattern can be obtained in which multiple spots are observed within a ring-shaped region centered on the direct spot.

[0377] [a-like OS] The a-like OS is an oxide semiconductor having a structure between the nc-OS and the amorphous oxide semiconductor. The a-like OS has a pore or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS. Furthermore, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and CAAC-OS.

[0378] <<Oxide semiconductor structure>> Next, the above-mentioned CAC-OS will be described in detail, which relates to the material composition.

[0379] [CAC-OS] CAC-OS is a material structure in which elements constituting a metal oxide are unevenly distributed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or a similar size range. Hereinafter, a metal oxide in which one or more metal elements are unevenly distributed and the regions containing the metal elements are mixed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or a similar size range, is also referred to as a mosaic or patch state.

[0380] Furthermore, CAC-OS has a mosaic structure in which the material is separated into first and second regions, and the first regions are distributed throughout the film (hereinafter also referred to as a cloud structure). That is, CAC-OS is a composite metal oxide having a structure in which the first and second regions are mixed.

[0381] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in the In-Ga-Zn oxide, the first region is a region where [In] is larger than [In] in the composition of the CAC-OS film. The second region is a region where [Ga] is larger than [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is a region where [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. The second region is a region where [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

[0382] Specifically, the first region is a region whose main component is indium oxide, indium zinc oxide, or the like. The second region is a region whose main component is gallium oxide, gallium zinc oxide, or the like. In other words, the first region can be rephrased as a region whose main component is In. The second region can be rephrased as a region whose main component is Ga.

[0383] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0384] In addition, CAC-OS in In-Ga-Zn oxide refers to a material structure containing In, Ga, Zn, and O, in which some regions primarily composed of Ga and other regions primarily composed of In are randomly arranged in a mosaic pattern. Therefore, it is presumed that CAC-OS has a structure in which metal elements are distributed nonuniformly.

[0385] The CAC-OS can be formed, for example, by a sputtering method without heating the substrate. When the CAC-OS is formed by a sputtering method, one or more of an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as a deposition gas. The lower the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition, the better. For example, the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition is preferably 0% or more and less than 30%, and more preferably 0% or more and 10% or less.

[0386] Furthermore, for example, in the case of CAC-OS in an In-Ga-Zn oxide, EDX mapping obtained using EDX (Energy Dispersive X-ray spectroscopy) confirms that the CAC-OS has a structure in which a region containing In as a main component (first region) and a region containing Ga as a main component (second region) are unevenly distributed and mixed.

[0387] Here, the first region has higher conductivity than the second region. That is, the flow of carriers through the first region causes the metal oxide to exhibit conductivity. Therefore, the first region is distributed in a cloud-like manner in the metal oxide, thereby achieving a high field-effect mobility (μ).

[0388] On the other hand, the second region has higher insulating properties than the first region. That is, the second region is distributed in the metal oxide, thereby suppressing leakage current.

[0389] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region act complementarily, thereby providing the CAC-OS with a switching function (the ability to turn on and off). In other words, CAC-OS has a conductive function in part of the material and an insulating function in part of the material, and the material as a whole functions as a semiconductor. By separating the conductive function from 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 behavior can be achieved.

[0390] Furthermore, a transistor using CAC-OS has high reliability, making it ideal for various semiconductor devices such as display devices.

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

[0392] <Transistors containing oxide semiconductors> Next, a case where the oxide semiconductor is used in a transistor will be described.

[0393] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0394] For the transistor, an oxide semiconductor with a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 Less than 1 × 10 15 cm -3 or less, more preferably 1 × 10 13 cm -3Less than 1×10, more preferably 11 cm -3 or less, more preferably 1 × 10 10 cm -3 Less than 1 x 10 -9 cm -3 That is all. Note that in order to reduce the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification and the like, a semiconductor having a low impurity concentration and a low density of defect states is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Note that an oxide semiconductor having a low carrier concentration may also be referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor.

[0395] Furthermore, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore the density of trap states may also be low.

[0396] Furthermore, charges trapped in the trap states of an oxide semiconductor take a long time to disappear and may behave like fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0397] Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. Furthermore, 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 impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon.

[0398] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0399] When an oxide semiconductor contains silicon or carbon, which is one of the Group 14 elements, defect levels are formed in the oxide semiconductor. Therefore, the concentrations of silicon and carbon in the oxide semiconductor and those near the interface with the oxide semiconductor (concentrations obtained by secondary ion mass spectrometry (SIMS)) are calculated as follows: 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0400] Furthermore, when an oxide semiconductor contains an alkali metal or alkaline earth metal, defect levels may be formed and carriers may be generated. Therefore, a transistor using an oxide semiconductor containing an alkali metal or alkaline earth metal is likely to have normally-on characteristics. Therefore, when the concentration of the alkali metal or alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 18 atoms / cm 3 Less than or equal to 2 x 10 16 atoms / cm 3 Do the following:

[0401] Furthermore, when nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor tends to have normally-on characteristics. Alternatively, when nitrogen is contained in an oxide semiconductor, trap states may be formed. As a result, the electrical characteristics of the transistor may become unstable. For this reason, the nitrogen concentration in the oxide semiconductor obtained by SIMS is set to 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than 1×10, more preferably 18 atoms / cm 3 Less than 5 × 10, more preferably 17 atoms / cm 3 Do the following:

[0402] Furthermore, hydrogen contained in an oxide semiconductor may react with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. When hydrogen enters the oxygen vacancy, electrons serving as carriers may be generated. Furthermore, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons serving as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. For this reason, it is preferable to reduce the amount of hydrogen in the oxide semiconductor as much as possible. Specifically, the hydrogen concentration in an oxide semiconductor measured by SIMS is 1×10 20 atoms / cm 3 Less than 1 x 10 19 atoms / cm 3 less than 5 × 10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 Make it less than.

[0403] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0404] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

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

[0406] The electronic devices of this embodiment include the display device of one embodiment of the present invention. The display device of one embodiment of the present invention can easily achieve high definition, high resolution, and a large size. Therefore, the display device of one embodiment of the present invention can be used as a display portion of various electronic devices.

[0407] Furthermore, the display device of one embodiment of the present invention can be manufactured at low cost, which leads to a reduction in the manufacturing cost of electronic devices.

[0408] Examples of electronic devices include electronic devices with relatively large screens such as television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproduction devices.

[0409] In particular, the display device of one embodiment of the present invention can achieve high resolution and is therefore suitable for use in electronic devices having a relatively small display area. Examples of such electronic devices include information terminals (wearable devices) such as wristwatches and bracelets, as well as head-mounted wearable devices such as VR devices and glasses-type AR devices. Further examples of wearable devices include SR devices and MR devices.

[0410] The display device of one embodiment of the present invention preferably has an extremely high resolution such as HD (1280 × 720 pixels), FHD (1920 × 1080 pixels), WQHD (2560 × 1440 pixels), WQXGA (2560 × 1600 pixels), 4K2K (3840 × 2160 pixels), or 8K4K (7680 × 4320 pixels). A resolution of 4K2K, 8K4K, or higher is particularly preferable. Furthermore, the pixel density (resolution) of the display device of one embodiment of the present invention is preferably 300 ppi or higher, more preferably 500 ppi or higher, more preferably 1000 ppi or higher, more preferably 2000 ppi or higher, more preferably 3000 ppi or higher, more preferably 5000 ppi or higher, and even more preferably 7000 ppi or higher. By using a display device with such high resolution or high definition, it is possible to further enhance the sense of presence and depth in electronic devices for personal use such as portable or home use.

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

[0412] The electronic device of this embodiment may have an antenna. By receiving a signal through the antenna, images, information, and the like can be displayed on a display portion. In addition, when the electronic device has an antenna and a secondary battery, the antenna may be used for contactless power transmission.

[0413] The electronic device of this embodiment may have a sensor (including a function to measure force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0414] The electronic device of the present embodiment can have various functions, such as a function 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, time, etc., a function to execute various software (programs), a wireless communication function, a function to read out programs or data recorded on a recording medium, etc.

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

[0416] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508. The display portion 6502 has a touch panel function.

[0417] The display device of one embodiment of the present invention can be applied to the display portion 6502.

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

[0419] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0420] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by adhesive layers (not shown).

[0421] In an area outside the display unit 6502, a part of the display panel 6511 is folded back, and an FPC 6515 is connected to the folded back part. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0422] The flexible display (flexible display device) of one embodiment of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted thereon while keeping the thickness of the electronic device small. Furthermore, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0423] 19A shows an example of a television device. A television device 7100 has a display unit 7000 built into a housing 7101. Here, the housing 7101 is supported by a stand 7103.

[0424] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0425] 19A can be operated using operation switches provided on the housing 7101 and a separate remote control 7111. Alternatively, a touch sensor may be provided in the display unit 7000, and the television 7100 may be operated by touching the display unit 7000 with a finger or the like. The remote control 7111 may have a display unit that displays information output from the remote control 7111. Using operation keys or a touch panel provided on the remote control 7111, the channel and volume can be controlled, and the video displayed on the display unit 7000 can be controlled.

[0426] The television device 7100 is configured to include a receiver, a modem, and the like. The receiver can receive general television broadcasts. In addition, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0427] 19B shows an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. A display portion 7000 is incorporated in the housing 7211.

[0428] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0429] 19C and 19D show an example of digital signage.

[0430] 19C includes a housing 7301, a display unit 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0431] 19D shows a digital signage 7400 attached to a cylindrical pillar 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pillar 7401.

[0432] 19C and 19D, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0433] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it will attract people's attention, which can increase the advertising effectiveness of, for example, advertisements.

[0434] Applying a touch panel to the display unit 7000 is preferable because it not only displays images or videos on the display unit 7000 but also allows the user to intuitively operate it. Furthermore, when used to provide information such as route information or traffic information, intuitive operation can improve usability.

[0435] 19C and 19D, it is preferable that the digital signage 7300 or the digital signage 7400 can wirelessly link with an information terminal 7311 or an information terminal 7411 such as a smartphone carried by a user. For example, advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or the information terminal 7411. Furthermore, the display on the display unit 7000 can be switched by operating the information terminal 7311 or the information terminal 7411.

[0436] Furthermore, it is also possible to cause the digital signage 7300 or the digital signage 7400 to execute a game using the screen of the information terminal 7311 or the information terminal 7411 as an operation means (controller), thereby allowing an unspecified number of users to simultaneously participate in and enjoy the game.

[0437] FIG. 20A is a diagram showing the appearance of the camera 8000 with the viewfinder 8100 attached.

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

[0439] The camera 8000 can capture an image by pressing a shutter button 8004 or touching a display unit 8002 that functions as a touch panel.

[0440] The housing 8001 has a mount with electrodes, and can be connected to a finder 8100 as well as a strobe device and the like.

[0441] The finder 8100 includes a housing 8101, a display portion 8102, a button 8103, and the like.

[0442] The housing 8101 is attached to the camera 8000 by a mount that engages with the mount of the camera 8000. The viewfinder 8100 can display an image received from the camera 8000 on a display unit 8102.

[0443] The button 8103 has a function such as a power button.

[0444] The display device of one embodiment of the present invention can be applied to a display portion 8002 of a camera 8000 and a display portion 8102 of a finder 8100. Note that the camera 8000 may have a built-in finder.

[0445] FIG. 20B is a diagram showing the appearance of the head mounted display 8200.

[0446] The head-mounted display 8200 includes a mounting portion 8201, a lens 8202, a main body 8203, a display portion 8204, and a cable 8205. The mounting portion 8201 has a built-in battery 8206.

[0447] A cable 8205 supplies power from a battery 8206 to the main body 8203. The main body 8203 includes a wireless receiver or the like, and can display received video information on a display portion 8204. The main body 8203 also includes a camera, and can use information on the movement of the user's eyeballs or eyelids as an input means.

[0448] The wearing unit 8201 may have a function of recognizing the line of sight by providing a plurality of electrodes at positions that come into contact with the user, capable of detecting a current that flows in accordance with the movement of the user's eyeballs. The wearing unit 8201 may also have a function of monitoring the user's pulse rate based on the current that flows through the electrodes. The wearing unit 8201 may also have various sensors, such as a temperature sensor, a pressure sensor, and an acceleration sensor, and may also have a function of displaying the user's biological information on the display unit 8204 and a function of changing the image displayed on the display unit 8204 in accordance with the movement of the user's head.

[0449] The display device of one embodiment of the present invention can be applied to the display portion 8204.

[0450] 20C to 20E are diagrams showing the appearance of a head mounted display 8300. The head mounted display 8300 includes a housing 8301, a display portion 8302, a band-shaped fixture 8304, and a pair of lenses 8305.

[0451] A user can view the display on the display portion 8302 through the lens 8305. Note that it is preferable to arrange the display portion 8302 in a curved manner because the user can feel a high sense of presence. In addition, by viewing different images displayed in different regions of the display portion 8302 through the lens 8305, it is possible to perform 3D display using parallax. Note that the present invention is not limited to a configuration in which one display portion 8302 is provided, and two display portions 8302 may be provided, with one display portion being provided for each eye of the user.

[0452] The display device of one embodiment of the present invention can be applied to the display portion 8302. The display device of one embodiment of the present invention can also achieve extremely high resolution. For example, even when the display is enlarged and viewed using the lens 8305 as shown in FIG. 20E, the pixels are hardly visible to the user. That is, the display portion 8302 allows the user to view a highly realistic image.

[0453] 20F is a diagram showing the appearance of a goggle-type head-mounted display 8400. The head-mounted display 8400 includes a pair of housings 8401, a mounting portion 8402, and a cushioning member 8403. A display portion 8404 and a lens 8405 are provided in each of the pair of housings 8401. By displaying different images on the pair of display portions 8404, 3D display using parallax can be performed.

[0454] A user can view the display portion 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 portion 8404 is preferably a square or a horizontally long rectangle. This can enhance the sense of realism.

[0455] The wearing part 8402 is preferably adjustable to fit the size of the user's face and has plasticity and elasticity to prevent it from slipping off. Furthermore, a part of the wearing part 8402 preferably has a vibration mechanism that functions as a bone conduction earphone. This allows the user to enjoy video and audio simply by wearing the earphone, without the need for separate audio equipment such as earphones or speakers. The housing 8401 may also have a function to output audio data via wireless communication.

[0456] The mounting unit 8402 and the buffer member 8403 are portions that come into contact with the user's face (forehead, cheeks, etc.). The close contact of the buffer member 8403 with the user's face can prevent light leakage and enhance the sense of immersion. The buffer member 8403 is preferably made of a soft material so that it can be in close contact with the user's face when the user wears the head-mounted display 8400. For example, materials such as rubber, silicone rubber, urethane, and sponge can be used. Furthermore, using a sponge or the like with its surface covered with cloth or leather (natural leather or synthetic leather) can prevent gaps from forming between the user's face and the buffer member 8403, thereby effectively preventing light leakage. Furthermore, using such materials is preferable because they feel pleasant to the touch and do not cause the user to feel cold when worn in cold seasons. It is preferable that components that come into contact with the user's skin, such as the buffer member 8403 or the mounting unit 8402, be removable for easy cleaning or replacement.

[0457] The electronic device shown in Figures 21A to 21F has a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including the function of measuring force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone 9008, etc.

[0458] 21A to 21F have various functions. For example, they may have a function 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 using various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. Note that the functions of the electronic device are not limited to these, and the electronic device may have various other functions. The electronic device may have multiple display units. Furthermore, the electronic device may have a function to include a camera or the like to capture still images or videos and store them on a recording medium (external or built-in to the camera), a function to display the captured images on the display unit, etc.

[0459] The display device of one embodiment of the present invention can be applied to the display portion 9001 .

[0460] The electronic device shown in FIGS. 21A to 21F will be described in detail below.

[0461] FIG. 21A is a perspective view showing a mobile information terminal 9101. The mobile information terminal 9101 can be used as, for example, a smartphone. The mobile information terminal 9101 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, and the like. The mobile information terminal 9101 can display text and image information on multiple surfaces thereof. FIG. 21A shows an example in which three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include a notification of an incoming email, SNS, or phone call, the title of the email or SNS, the sender's name, the date and time, the remaining battery level, and the strength of antenna reception. Alternatively, an icon 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0462] 21B is a perspective view showing mobile information terminal 9102. Mobile information terminal 9102 has a function of displaying information on three or more sides of display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, while carrying mobile information terminal 9102 in a breast pocket of clothes, the user can check information 9053 displayed in a position that can be observed from above mobile information terminal 9102. The user can check the display without taking mobile information terminal 9102 out of the pocket and decide, for example, whether to answer a call.

[0463] FIG. 21C is a perspective view showing a wristwatch-type mobile information terminal 9200. The mobile information terminal 9200 can be used as, for example, a smart watch (registered trademark). The display surface of the display unit 9001 is curved, and a display can be performed along the curved display surface. The mobile information terminal 9200 can also perform hands-free communication by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and reception with another information terminal and charge itself via a connection terminal 9006. Note that charging may be performed by wireless power supply.

[0464] 21D to 21F are perspective views showing a foldable mobile information terminal 9201. FIG. 21D shows the mobile information terminal 9201 in an unfolded state, FIG. 21F shows it in a folded state, and FIG. 21E is a perspective view showing a state in the process of changing from one of FIG. 21D and FIG. 21F to the other. The mobile information terminal 9201 is highly portable when folded, and has a seamless, wide display area when unfolded, providing excellent viewability of the display. The display unit 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display unit 9001 can be bent with a curvature radius of 0.1 mm or more and 150 mm or less.

[0465] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings. [Example]

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

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

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

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

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

[0471] [Display results] Photographs of the manufactured display panel are shown in Figures 22A and 22B. By using a color-coding method without a metal mask, we were able to achieve a color image with an extremely high resolution of 2731 ppi.

[0472] [Spectral Measurement] Spectral measurements were performed on the manufactured display panel. The measurements were performed by measuring the wavelength dependence of spectral radiant intensity with all pixels of the display panel displayed in red (R), green (G), blue (B), and black (BK). For comparison, similar evaluations were also performed on two types of display panels (Comparative Example 1 and Comparative Example 2) using a white OLED and a color filter. The resolution of Comparative Example 1 and Comparative Example 2 was comparable to that of the display panel manufactured in this example (referred to as Example).

[0473] 23A, 23B, and 23C show the results of spectral measurement in Example, Comparative Example 1, and Comparative Example 2, respectively. In addition, in FIGS. 24A, 24B, and 24C, the vertical axis is a logarithmic axis. In each figure, the horizontal axis is wavelength [nm], and the vertical axis is spectral radiance [W / sr / m 2 / nm]. In addition, the results of black display (BK) are omitted in Figures 23A, 23B, and 23C.

[0474] Focusing on the example, it can be seen that the half-widths of all R, G, and B are small and there is almost no overlap of the spectra of each color. Furthermore, as shown in Figure 24A, almost no light emission was observed in the black display, and it was found that there was extremely little light leakage in the black display.

[0475] On the other hand, when we focus on Comparative Example 1, we can see that the half-width of the spectrum is larger than that of the Examples. Furthermore, peaks are observed around a wavelength of 650 nm in the blue display (B), and around wavelengths of 450 nm and 620 nm in the green display (G). These peaks are presumably due to the influence of crosstalk, which is a cause of the decrease in contrast. Furthermore, as shown in Figure 24B, slight emission is observed around wavelengths of 600 nm to 700 nm even in the black display, confirming the occurrence of light leakage.

[0476] In addition, in Comparative Example 2, as shown in FIG. 24C, no light leakage was observed during black display, but light emission due to crosstalk was observed around a wavelength of 600 nm during blue display (B) and green display (G).

[0477] From the above, it was confirmed that the display panel produced in this example had an extremely high resolution of 2731 ppi, but no crosstalk was observed, and extremely high contrast and color rendering properties were achieved. [Explanation of symbols]

[0478] 100: display device, 101: substrate, 103: pixel, 110: light-emitting element, 110B: light-emitting element, 110G: light-emitting element, 110R: light-emitting element, 111: pixel electrode, 111B: pixel electrode, 111C: connection electrode, 111G: pixel electrode, 111R: pixel electrode, 112: EL layer, 112B: EL layer, 112Bf: EL film, 112G: EL layer, 112Gf: EL film, 112R: EL layer, 112Rf: EL film, 113: common electrode, 114: common layer, 121: protective layer, 130: region, 131: insulating layer, 131a: insulating layer, 131af: insulating film, 131ap: insulating layer, 131b: Insulating layer, 131bf: insulating film, 143a: resist mask, 143b: resist mask, 143c: resist mask, 144: sacrificial film, 144B: sacrificial film, 144G: sacrificial film, 144R: sacrificial film, 145: sacrificial layer, 145B: sacrificial layer, 145G: sacrificial layer, 145R: sacrificial layer, 201: transistor, 204: connecting portion, 205: transistor, 209: transistor, 211: insulating layer, 213: insulating layer, 214: insulating layer, 215: insulating layer, 218: insulating layer, 221: conductive layer, 222a: conductive layer, 222b: conductive layer, 223: conductive layer, 225: insulating layer, 228: Region, 231: semiconductor layer, 231i: channel formation region, 231n: low resistance region, 240: capacitor, 241: conductive layer, 242: connection layer, 243: insulating layer, 245: conductive layer, 251: conductive layer, 252: conductive layer, 254: insulating layer, 255: insulating layer, 256: plug, 261: insulating layer, 262: insulating layer, 263: insulating layer, 264: insulating layer, 265: insulating layer, 271: plug, 274: plug, 274a: conductive layer, 274b: conductive layer, 280: display module, 281: display unit, 282: circuit unit, 283: pixel circuit unit, 283a: pixel circuit, 284: pixel unit, 284a : pixel, 285: terminal portion, 286: wiring portion, 290: FPC, 291: substrate, 292: substrate, 301: substrate, 301A: substrate, 301B: substrate, 310: transistor, 310A: transistor, 310B: transistor, 311: conductive layer, 312: low resistance region, 313: insulating layer, 314: insulating layer, 315: element isolation layer, 320: transistor, 321: semiconductor layer, 323: insulating layer, 324: conductive layer, 325: conductive layer, 326: insulating layer, 327: conductive layer, 328: insulating layer, 329: insulating layer, 331: substrate, 332: insulating layer, 341: conductive layer, 342: conductive layer,343: plug, 400A: display device, 400C: display device, 400D: display device, 400E: display device, 400F: display device, 410: protective layer, 411a: pixel electrode, 411b: pixel electrode, 411c: pixel electrode, 414: insulating layer, 416: protective layer, 416a: EL layer, 416b: EL layer, 416c: EL layer, 417: light-shielding layer, 418a: conductive layer, 418b: conductive layer, 418c: conductive layer, 419: resin layer, 420: substrate, 421: insulating layer, 421b: insulating layer, 430a: light-emitting element, 430b: light-emitting element, 430c: light-emitting element, 442: adhesive layer, 443: air Between, 451: substrate, 452: substrate, 462: display unit, 464: circuit, 465: wiring, 466: conductive layer, 472: FPC, 473: IC, 772: lower electrode, 785: colored layer, 786: EL layer, 786a: EL layer, 786b: EL layer, 788: upper electrode, 4411: light-emitting layer, 4412: light-emitting layer, 4413: light-emitting layer, 4420: layer, 4420-1: layer, 4420-2: layer, 4430: layer, 4430-1: layer, 4430-2: layer, 6500: electronic device, 6501: housing, 6502: display unit, 6503: power button, 6504: button, 6505: speaker, 650 6: microphone, 6507: camera, 6508: light source, 6510: protective member, 6511: display panel, 6512: optical member, 6513: touch sensor panel, 6515: FPC, 6516: IC, 6517: printed circuit board, 6518: battery, 7000: display unit, 7100: television device, 7101: housing, 7103: stand, 7111: remote control device, 7200: notebook personal computer, 7211: housing, 7212: keyboard, 7213: pointing device, 7214: external connection port, 7300: digital signage, 730 1: Housing, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 8000: Camera, 8001: Housing, 8002: Display, 8003: Operation buttons, 8004: Shutter button, 8006: Lens, 8100: Viewfinder, 8101: Housing, 8102: Display, 8103: Button, 8200: Head-mounted display, 8201: Wearing part, 8202: Lens, 8203: Main body, 8204: Display, 8205: Cable, 8206: Battery, 8300: Head-mounted display,8301: Housing, 8302: Display unit, 8304: Fixing device, 8305: Lens, 8400: Head mounted display, 8401: Housing, 8402: Wearing part, 8403: Cushioning material, 8404: Display unit, 8405: Lens, 9000: Housing, 9001: Display unit, 9003: Speaker, 9005: Operation key, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9101: Portable information terminal, 9102: Portable information terminal, 9200: Portable information terminal, 9201: Portable information terminal,

Claims

1. A display device having a first pixel, a second pixel arranged adjacent to the first pixel, a first insulating layer, and a second insulating layer, the first pixel has a first pixel electrode, a first EL layer on the first pixel electrode, and a common electrode on the first EL layer; the second pixel has a second pixel electrode, a second EL layer on the second pixel electrode, and the common electrode on the second EL layer; a side surface of the first EL layer and a side surface of the second EL layer have a region in contact with the first insulating layer; the second insulating layer is provided on and in contact with the first insulating layer and is disposed below the common electrode; the first insulating layer comprises an inorganic material; the second insulating layer comprises an organic material; a side surface of the first pixel electrode is covered with the first EL layer; A display device in which a side surface of the second pixel electrode is covered with the second EL layer.

2. In claim 1, The display device has an upper surface of the first EL layer, an upper surface of the second EL layer, and an upper surface of the first insulating layer, each having an area in contact with the common electrode.

3. In claim 1, the first pixel has a common layer disposed between the first EL layer and the common electrode; the second pixel has the common layer disposed between the second EL layer and the common electrode; The display device, wherein the upper surface of the first EL layer, the upper surface of the second EL layer, and the upper surface of the first insulating layer have regions in contact with the common layer.

4. In any one of claims 1 to 3, In a cross-sectional view of the display device, the first insulating layer has a region that protrudes above at least one of an upper surface of the first EL layer and an upper surface of the second EL layer.

5. In any one of claims 1 to 3, In a cross-sectional view of the display device, at least one of the first EL layer and the second EL layer has a region that protrudes above an upper surface of the first insulating layer.

6. In any one of claims 1 to 3, In a cross-sectional view of the display device, the upper surface of the second insulating layer has a concave curved shape.

7. In any one of claims 1 to 3, In a cross-sectional view of the display device, the upper surface of the second insulating layer has a convex curved shape.

Images