Display device, display module, and method of manufacturing a display device

Abstract

Provided is a high-definition display device. The display device is provided with a plurality of light-emitting elements that emit light of different colors. A microcavity structure (microresonator structure) is realized for the light-emitting elements to intensify light of a specific wavelength. The light-emitting elements emitting light of different colors each include, on a lower electrode, a reflection layer and a conductive layer having a different thickness. The bottom electrode and the conductive layer are electrically connected within a light-emitting element. The light-emitting elements are separately formed so that different colors are intensified due to different optical path lengths.

Description

Technical Field

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

[0002] Note that one aspect of the present invention is not limited to the above technical field. Examples of the technical field of one aspect of the present invention disclosed in this specification and the like include semiconductor devices, display devices, light-emitting devices, power storage devices, storage devices, electronic devices, lighting devices, input devices, input / output devices, their driving methods, or their manufacturing methods. In this specification and the like, the semiconductor device shall refer to all devices that can function by utilizing semiconductor characteristics.

Background Art

[0003] In recent years, higher definition of display panels has been demanded. Devices that require high-definition display panels include, for example, devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), or mixed reality (MR), which have been actively developed in recent years.

[0004] In addition, typical display devices applicable 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), or electronic paper that performs display by an electrophoretic method or the like.

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

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] For example, in the above-described wearable devices for VR, AR, SR, or MR, it is necessary to provide a focusing lens between the eyes and the display panel. Since a part of the screen is enlarged by the lens, if the resolution of the display panel is low, there is a problem that the sense of reality and immersion is reduced.

[0008] In addition, the display panel is required to have high color reproducibility. Particularly in the devices for VR, AR, SR, or MR described above, by using a display panel with high color reproducibility, a display close to the actual object color can be performed, and the sense of reality and immersion can be enhanced.

[0009] One aspect of the present invention is to provide an extremely high-resolution display device as one of the problems. One aspect of the present invention is to provide a display device in which high color reproducibility is realized as one of the problems. One aspect of the present invention is to provide a high-brightness display device as one of the problems. One aspect of the present invention is to provide a highly reliable display device as one of the problems. Further, one aspect of the present invention is to provide a method for manufacturing the above-described display device as one of the problems.

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

Means for Solving the Problems

[0011] One aspect of the present invention is a display device having a first light-emitting element and a second light-emitting element. The first light-emitting element has a first lower electrode, a first reflective layer, a first insulating layer, a first conductive layer, a light-emitting layer, and an upper electrode. Further, the first lower electrode, the first reflective layer, the first insulating layer, the first conductive layer, the light-emitting layer, and the upper electrode are laminated in this order. The second light-emitting element has a second lower electrode, a second reflective layer, a second insulating layer, a second conductive layer, a light-emitting layer, and an upper electrode. Further, the second lower electrode, the second reflective layer, the second insulating layer, the second conductive layer, the light-emitting layer, and the upper electrode are laminated in this order. The first conductive layer, the first insulating layer, the second conductive layer, and the second insulating layer have translucency. The second conductive layer is thicker than the first conductive layer. The upper electrode has transmissivity and reflectivity with respect to visible light. The first lower electrode is electrically connected to the first conductive layer. The second lower electrode is electrically connected to the second conductive layer.

[0012] In the above, it is preferable that the first lower electrode is covered by the first conductive layer. Further, it is preferable that the second lower electrode is covered by the second conductive layer.

[0013] One aspect of the present invention is a display device having a first light-emitting element, a second light-emitting element, a first plug, and a second plug. The first light-emitting element has a first lower electrode, a first reflective layer, a first insulating layer, a first conductive layer, a light-emitting layer, and an upper electrode. Further, the first lower electrode, the first reflective layer, the first insulating layer, the first conductive layer, the light-emitting layer, and the upper electrode are laminated in this order. The second light-emitting element has a second lower electrode, a second reflective layer, a second insulating layer, a second conductive layer, a light-emitting layer, and an upper electrode. Further, the second lower electrode, the second reflective layer, the second insulating layer, the second conductive layer, the light-emitting layer, and the upper electrode are laminated in this order. The first conductive layer, the first insulating layer, the second conductive layer, and the second insulating layer have light-transmitting properties. The second conductive layer is thicker than the first conductive layer. The upper electrode has transmissivity and reflectivity with respect to visible light. The first lower electrode is electrically connected to the first conductive layer via the first plug. The second lower electrode is electrically connected to the second conductive layer via the second plug. The first plug is embedded in the first insulating layer, and the second plug is embedded in the second insulating layer.

[0014] In the above, it is preferable that the first conductive layer has a first film. Further, it is preferable that the second conductive layer has a second film and a third film. Furthermore, it is preferable that the second film and the third film are laminated in this order. It is preferable that the first film and the third film are films having the same composition.

[0015] In the above, it is preferable to have a circuit layer including a transistor. Further, it is preferable that the first light-emitting element is provided on the circuit layer and is electrically connected to the transistor. Furthermore, the transistor may contain a metal oxide having crystallinity or single-crystalline silicon in a semiconductor layer in which a channel is formed.

[0016] In the above, it is preferable to have a first circuit layer including a first transistor, a second circuit layer including a second transistor, a third insulating layer positioned on the first circuit layer, and a fourth insulating layer between the first circuit layer and the second circuit layer. Also, the first light-emitting element is preferably electrically connected to the first transistor. Further, in the above, the first transistor includes a metal oxide having crystallinity in a first semiconductor layer in which a channel is formed, and the second transistor preferably includes a metal oxide having crystallinity or single-crystalline silicon in a second semiconductor layer in which a channel is formed.

[0017] In the above, having a plurality of first light-emitting elements, the first light-emitting elements are preferably periodically arranged with a fineness of 2000 ppi or more. Also, the first light-emitting elements can be arranged in a delta array.

[0018] Another aspect of the present invention is a method for manufacturing a display device, including a step of separately forming a first lower electrode and a second lower electrode on a surface to be formed, a step of forming a first reflective layer on the first lower electrode and a second reflective layer on the second lower electrode, a step of forming a first insulating layer on the first reflective layer and a second insulating layer on the second reflective layer, a step of forming a first conductive layer covering the first lower electrode and a second conductive layer covering the second lower electrode, and a step of forming a light-emitting layer on the first conductive layer and the second conductive layer and an upper electrode on the light-emitting layer. Also, the second conductive layer is formed thicker than the first conductive layer, the first conductive layer and the second conductive layer are formed to have translucency, the first lower electrode is electrically connected to the first conductive layer, the second lower electrode is electrically connected to the second conductive layer, and the upper electrode is formed to have translucency and reflectivity.

[0019] Another aspect of the present invention is a method for manufacturing a display device, comprising: forming a first conductive film to be a first lower electrode and a second lower electrode on a surface to be formed; depositing a second conductive film to be a first reflective layer and a second reflective layer, covering the first conductive film; depositing a first insulating film to be a first insulating layer and a second insulating layer on the first conductive film; embedding a first plug and a second plug in the first insulating film and electrically connecting the first plug and the second plug to the first conductive film respectively; forming a first conductive layer on the first plug; and forming a second conductive layer on the second plug. Further, the first conductive film, the second conductive film, the first insulating film, the first conductive layer, and the second conductive layer are processed into an island shape to form a first lower electrode, a second lower electrode, a first reflective layer, a second reflective layer, a first insulating layer, and a second insulating layer, and forming a light-emitting layer on the first conductive layer and the second conductive layer, and forming an upper electrode on the light-emitting layer.

[0020] In addition, in the above, the second conductive layer is formed thicker than the first conductive layer, the first conductive layer and the second conductive layer are formed to have light transmissivity, the first conductive layer is electrically connected to the first lower electrode via the first plug, the second conductive layer is electrically connected to the second lower electrode via the second plug, and the upper electrode is formed to have light transmissivity and reflectivity.

Advantages of the Invention

[0021] According to one aspect of the present invention, an extremely high-definition display device can be provided. Or, a display device with high color reproducibility can be provided. Or, a high-brightness display device can be provided. Also, a highly reliable display device can be provided. Or, a method for manufacturing the above-described display device can be provided.

[0022] Note that the description of these effects does not prevent the existence of other effects. Note that one aspect of the present invention does not necessarily have all of these effects. Note that other effects can be extracted from the description in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0023] Figures 1A and 1B are diagrams showing a configuration example of a display device. Figures 2A and 2B are diagrams showing a configuration example of a display device. Figures 3A and 3B are diagrams showing a configuration example of a display device. Figures 4A to 4E are diagrams for explaining an example of a manufacturing method of a display device. Figures 5A to 5C are diagrams for explaining an example of a manufacturing method of a display device. Figures 6A to 6E are diagrams for explaining an example of a manufacturing method of a display device. Figures 7A to 7E are diagrams for explaining an example of a manufacturing method of a display device. Figures 8A and 8B are diagrams showing a configuration example of a display device. Figure 9 is a diagram showing a configuration example of a display device. Figure 10 is a diagram showing a configuration example of a display device. Figure 11 is a diagram showing a configuration example of a display device. Figure 12 is a diagram showing a configuration example of a display device. Figures 13A and 13B are diagrams showing a configuration example of a display module. Figures 14A and 14B are circuit diagrams showing an example of a display device. Figures 15A and 15C are circuit diagrams showing an example of a display device. Figure 15B is a timing chart showing an example of the operation of the display device. Figures 16A and 16B are diagrams showing a configuration example of an electronic device. Figures 17A and 17B are diagrams showing a configuration example of an electronic device.

Embodiments for Carrying Out the Invention

[0024] Hereinafter, embodiments will be described with reference to the drawings. However, the embodiments can be implemented in many different ways, and it is easily understood by those skilled in the art that the forms and details can be variously changed without departing from the spirit and its scope. Therefore, the present invention is not construed as being limited to the description of the following embodiments.

[0025] In the configuration of the invention described below, the same reference numerals are commonly used among different drawings for the same part or parts having the same or similar functions, and the repeated description thereof is omitted. Also, when referring to similar functions, the hatch patterns may be the same, and there may be cases where no reference numerals are particularly assigned.

[0026] In each of the drawings described in this specification, the size of each component, the thickness of the layer, or the region may be exaggerated for clarity. Therefore, it is not necessarily limited to that scale.

[0027] Note that ordinal numbers such as "first", "second", etc. in this specification are attached to avoid confusion of components and do not numerically limit them.

[0028] (Embodiment 1) In this embodiment, a display device according to one aspect of the present invention and a method for manufacturing the display device will be described.

[0029] A display device according to one aspect of the present invention includes a light-emitting element (also referred to as a light-emitting device) that emits light of different colors. The light-emitting element includes a lower electrode, an upper electrode, and a layer containing a light-emitting compound (also referred to as a light-emitting layer or an EL layer) between them. As the light-emitting element, it is preferable to use an electroluminescent element such as an organic EL element or an inorganic EL element. Alternatively, a light-emitting diode (LED) may be used.

[0030] Further, the light-emitting element has a conductive layer (also referred to as an optical adjustment layer) having transparency (light transmittance) with respect to visible light, a reflective layer that reflects visible light through the conductive layer, and an insulating layer having light transmittance. Furthermore, it is preferable to use a conductive film having light transmittance and reflectivity for the upper electrode of the light-emitting element. The light-emitting element realizes a so-called microcavity structure (micro resonator structure), and light of a specific wavelength is enhanced.

[0031] A display device according to one embodiment of the present invention preferably uses a light-emitting element that emits white light to express two or more different colors. In this case, the light-emitting layer and the upper electrode can be shared between two light-emitting elements that emit light of different colors, and the lower electrode can be electrically insulated between the elements. Furthermore, the distances between the light-emitting layer and the reflective layer are preferably different between the two light-emitting elements. This allows the light of different wavelengths to be intensified, and two or more different colors can be expressed using a light-emitting element that emits white light.

[0032] In a display device according to one embodiment of the present invention, a light-transmitting conductive layer is formed in multiple steps on a reflective layer formed on a lower electrode, thereby enabling conductive layers with different thicknesses to be formed for each light-emitting element. Furthermore, a light-transmitting insulating layer is preferably provided between the reflective layer and the conductive layer to prevent electrolytic corrosion of the reflective layer and the conductive layer. Then, a light-emitting layer and an upper electrode are formed on the upper surface of the conductive layer, thereby enabling light-emitting elements with different intensified colors due to different optical paths (optical path lengths) to be formed.

[0033] In a display device according to one embodiment of the present invention, a lower electrode and a conductive layer formed over a reflective layer are electrically connected to each other. The conductive layer is formed to cover the lower electrode and is electrically connected to the lower electrode. Alternatively, a plug may be provided between the conductive layer and the lower electrode.

[0034] That is, a display device according to one embodiment of the present invention has a structure in which a reflective layer is provided on a lower electrode provided on a formation surface, and a conductive layer is provided on the reflective layer. Furthermore, an insulating layer can be provided in contact with the reflective layer. The thickness of the conductive layer located between the light-emitting layer and the reflective layer can be controlled by depositing the conductive layer in multiple steps. The conductive layer included in the display device according to one embodiment of the present invention can also be called an optical adjustment layer because it has a function of adjusting the optical distance (also referred to as the optical path length) depending on its thickness.

[0035] Between two light-emitting elements, since they have conductive layers with different thicknesses respectively, the light emitted by each light-emitting element becomes light in which lights of different wavelengths are enhanced. And the difference in the optical distance of each light-emitting element is determined by the difference in the thickness of the conductive layer. As a result, since the optical distances of the two light-emitting elements can be controlled with high precision, not only is the color reproducibility high, but also the color unevenness between the light-emitting elements is reduced, and a display device with high display quality can be manufactured with high yield.

[0036] The display device according to one aspect of the present invention can extremely accurately produce light-emitting elements of different colors. Also, since the conductive layer and the lower electrode are electrically connected within the light-emitting element, it is possible to arrange the light-emitting elements extremely densely. Therefore, a display device with higher definition than conventional display devices can be realized. For example, it is preferable that a pixel having one or more light-emitting elements is arranged with a definition of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, still more preferably 6000 ppi or more, and 20000 ppi or less, or 30000 ppi or less, which is an extremely high-definition display device.

[0037] Here, for the sake of easy explanation, mainly two light-emitting elements have been described, but preferably, light-emitting elements exhibiting three primary colors, or four or more colors are provided. Specifically, it can be configured to have light-emitting units that respectively exhibit red (R), green (G), and blue (B) lights. Or, in addition to these, or instead of these, a configuration may be provided in which light-emitting elements that exhibit lights such as yellow (Y), cyan (C), magenta (M), and white (W) are provided.

[0038] Hereinafter, more specific configuration examples and manufacturing method examples will be described with reference to the drawings.

[0039] [Configuration Example 1] [Configuration Example 1-1] FIG. 1A is a schematic cross-sectional view for explaining a display device 100A according to an aspect of the present invention. The display device 100A includes a light-emitting element 120R, a light-emitting element 120G, and a light-emitting element 120B. The light-emitting element 120R is a light-emitting element that exhibits red, the light-emitting element 120G is a light-emitting element that exhibits green, and the light-emitting element 120B is a light-emitting element that exhibits blue.

[0040] In the following, when explaining matters common to the light-emitting element 120R, the light-emitting element 120G, and the light-emitting element 120B, the symbols added to the reference numerals may be omitted, and they may be described as the light-emitting element 120. Similarly, the conductive layer 114R, the conductive layer 114G, and the conductive layer 114B described later may also be described as the conductive layer 114. The conductive layer 114R is included in the light-emitting element 120R. Similarly, the conductive layer 114G is included in the light-emitting element 120G, and the conductive layer 114B is included in the light-emitting element 120B.

[0041] The light-emitting element 120 includes a conductive layer 111 that functions as a lower electrode, a reflective layer 112, an insulating layer 113, a conductive layer 114, an EL layer 115, and a conductive layer 116 that functions as an upper electrode. The insulating layer 113 and the conductive layer 114 have a function of transmitting visible light, and the conductive layer 116 has permeability and reflectivity with respect to visible light. The EL layer 115 contains a light-emitting compound.

[0042] The light-emitting element 120 can use an electroluminescent element that has a function of emitting light by a current flowing through the EL layer 115 by applying a potential difference between the conductive layer 111 and the conductive layer 116. In particular, it is preferable to apply an organic EL element using a light-emitting organic compound for the EL layer 115. Further, the light-emitting element 120 is preferably an element that emits white light having two or more peaks in the visible light region in the emission spectrum.

[0043] On the conductive layer 111, a reflective layer 112 is provided. The reflective layer 112 has reflectivity with respect to visible light. Further, an insulating layer 113 is provided on the reflective layer 112. The reflective layer 112 and the insulating layer 113 are provided to be smaller than the conductive layer 111 in a top view. That is, in a top view (plan view), it is sufficient that the respective ends of the reflective layer 112 and the insulating layer 113 are located inside the conductive layer 111. A part of the conductive layer 111 is preferably in contact with a conductive layer 114 described later. Further, it is preferable to make the sizes of the reflective layer 112 and the insulating layer 113 approach the size of the conductive layer 111 in a top view. Further, the reflective layer 112 and the insulating layer 113 preferably have an island shape in a top view.

[0044] A conductive layer 114 is provided on the insulating layer 113. The insulating layer 113 is located between the reflective layer 112 and the conductive layer 114 and has a function of preventing electrolytic corrosion from occurring when they come into contact. Further, as shown in the display device 100B of FIG. 1B, the insulating layer 113 may cover the end portion of the reflective layer 112. With such a configuration, the reflective layer 112 is surrounded by the insulating layer 113 and the lower electrode 111, and electrolytic corrosion with the conductive layer 114 can be surely prevented, which is preferable for improving the reliability of the display device. Further, the conductive layer 114 covers the conductive layer 111 and is electrically connected by contacting the conductive layer 111 at the end portion of the conductive layer 111. For this reason, it is not necessary to newly provide a contact for electrically connecting the conductive layer 111, and the opening (light emitting portion) can be widened, which is preferable.

[0045] The EL layer 115 and the conductive layer 116 are commonly provided over the light emitting elements 120R, 120G, and 120B. The conductive layer 116 functions as, for example, an upper electrode to which a common potential is applied. By providing them in common, the manufacturing procedure of the light emitting element 120 can be reduced, which is preferable. Further, a potential for controlling the amount of light emitted by the light emitting element 120 is independently applied to the conductive layer 111 provided for each light emitting element 120. The conductive layer 111 functions as, for example, a pixel electrode.

[0046] In the display device 100A, an insulating layer 117 is provided between the two light-emitting elements 120. The insulating layer 117 has a function of preventing the conductive layer 116 from being electrically short-circuited with the pixel electrode due to, for example, the thinning of the EL layer 115 caused by the step at the end of the conductive layer 114. Further, in order to enhance the coverage of the EL layer 115, as shown in FIG. 1A, the end of the insulating layer 117 located on the conductive layer 114 preferably has a tapered shape. The insulating layer 117 is located between two adjacent light-emitting elements 120 and covers the ends of the conductive layer 114 included in each light-emitting element 120. For example, in FIG. 1A, the insulating layer 117 located between the light-emitting element 120R and the light-emitting element 120G covers the respective ends of the conductive layer 114R and the conductive layer 114G. Also, in FIG. 1A, the insulating layer 117 located between the light-emitting element 120G and the light-emitting element 120B covers the respective ends of the conductive layer 114G and the conductive layer 114B.

[0047] Here, the conductive layer 114 provided in each light-emitting element 120 has a different thickness for each light-emitting element. Among the three conductive layers 114, the conductive layer 114B is the thinnest and the conductive layer 114R is the thickest. As shown in FIG. 1A here, the distance between the upper surface of the reflective layer 112 and the lower surface of the conductive layer 116 (i.e., the interface between the conductive layer 116 and the EL layer 115) in each light-emitting element is defined as distance D R , distance D G , distance D B . When this is done, distance D R is the largest and distance D B is the smallest. The difference between distance D R , distance D G , and distance D B corresponds to the difference in the optical distance (optical path length) in each light-emitting element.

[0048] Among the three light-emitting elements, since the light-emitting element 120R has the longest optical path length, it emits the light R in which the light located at the longest wavelength is enhanced. On the other hand, since the light-emitting element 120B has the shortest optical path length, it emits the light B in which the light located at the shortest wavelength is enhanced. The light-emitting element 120G emits the light G in which the light of the intermediate wavelength is enhanced. For example, the light R can be the light in which the red light is enhanced, the light G can be the light in which the green light is enhanced, and the light B can be the light in which the blue light is enhanced.

[0049] With such a configuration, for each light-emitting element of different colors, it is not necessary to separately fabricate the EL layer of the light-emitting element 120. Using elements with the same configuration, a color display with high color reproducibility can be performed. In addition, the light-emitting elements 120 can be arranged extremely densely. For example, a display device with a fineness exceeding 2000 ppi can be realized.

[0050] The display device 100A includes the above-described light-emitting element 120R, light-emitting element 120G, and light-emitting element 120B on a substrate 101 having a semiconductor circuit. The display device 100A also has an insulating layer 121 and a plug 131.

[0051] As the substrate 101, a circuit board having transistors or wirings can be used. When the passive matrix method or the segment method is applicable, an insulating substrate such as a glass substrate can be used as the substrate 101. The substrate 101 is a substrate provided with a circuit (also referred to as a pixel circuit) for driving each light-emitting element or a semiconductor circuit that functions as a driving circuit for driving the pixel circuit. A more specific configuration example of the substrate 101 will be described later.

[0052] The substrate 101 and the conductive layer 111 of the light-emitting element 120 are electrically connected via the plug 131. The plug 131 is formed to be embedded in an opening provided in the insulating layer 121. The conductive layer 111 is provided in contact with the upper surface of the plug 131.

[0053] 〔Configuration Example 1-2〕 FIG. 2A is a schematic cross-sectional view of the display device 100C. The display device 100C is different from the display device 100A mainly in that it has a plug 130 and the configuration of the conductive layer 114 is different.

[0054] On each conductive layer 111 of the display device 100C, a reflective layer 112, an insulating layer 113, and a conductive layer 114 with different thicknesses for each light-emitting element are laminated in this order. The conductive layer 114 is electrically connected to the conductive layer 111 via the plug 130. This is preferable because it is not necessary to provide the conductive layer 114 larger than the conductive layer 111. With such a configuration, the area of the conductive layer 111 that functions as a pixel electrode can be made larger. Furthermore, since the plug 130 can be provided between the conductive layer 114 and the conductive layer 111, the aperture ratio of the pixel can be increased. In FIG. 2A, the plug 130 is embedded in the insulating layer 113 and the reflective layer 112, but as in the display device 100D shown in FIG. 2B, the plug 130 may be embedded in the insulating layer 113 and in contact with the reflective layer 112. At this time, a configuration in which the reflective layer 112 is in contact with the plug 130 without providing the conductive layer 111 may be used, but when the reflective layer 112 is thin, etc., when forming an opening for forming the plug 130 in the insulating layer 113, the reflective layer 112 may be penetrated, so it is preferable to provide the conductive layer 111.

[0055] 〔Configuration Example 1-3〕 FIG. 3A is a schematic cross-sectional view of the display device 100E, and FIG. 3B is a schematic cross-sectional view of the display device 100F. The display device 100E is mainly different from the display device 100A, and the display device 100F is mainly different from the display device 100C in that the configurations of the conductive layer 114R of the light-emitting element 120R and the conductive layer 114G of the light-emitting element 120G are different.

[0056] The conductive layer 114R has a laminated structure in which a conductive layer 143, a conductive layer 142, and a conductive layer 141 are laminated in this order from the reflective layer 112 side. The conductive layer 114G has a laminated structure in which a conductive layer 142 and a conductive layer 141 are laminated from the reflective layer 112 side. The conductive layer 114B is constituted by the conductive layer 141.

[0057] It is preferable to use a material that transmits visible light for the conductive layer 141, the conductive layer 142, and the conductive layer 143. Also, it is preferable to use the same material because the processing equipment can be shared.

[0058] [Regarding Components] [Light-Emitting Element] As the light-emitting element that can be used for the light-emitting element 120, an element capable of self-luminescence can be used, and an element whose luminance is controlled by current or voltage is included in that category. For example, an LED, an organic EL element, an inorganic EL element, etc. can be used. In particular, it is preferable to use an organic EL element.

[0059] The light-emitting element has a top emission type, a bottom emission type, a dual emission type, etc. For the electrode on the light extraction side, a conductive film that transmits visible light is used. Also, for the electrode on the side where light is not extracted, a conductive film that reflects visible light is used.

[0060] In one aspect of the present invention, a top emission type or dual emission type light-emitting element that emits light particularly on the side opposite to the surface to be formed can be preferably used.

[0061] The EL layer 115 has at least a light-emitting layer. As layers other than the light-emitting layer, the EL layer 115 may further have a layer containing a substance with high hole injection property, a substance with high hole transport property, a hole blocking material, a substance with high electron transport property, a substance with high electron injection property, an electron blocking material, or a bipolar substance (a substance with high electron transport property and high hole transport property), etc.

[0062] Either a low molecular compound or a high molecular compound can be used for the EL layer 115, and it may contain an inorganic compound. The layers constituting the EL layer 115 can be formed by methods such as a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, a coating method, etc.

[0063] When a voltage higher than the threshold voltage of the light-emitting element 120 is applied between the cathode and the anode, holes are injected into the EL layer 115 from the anode side, and electrons are injected from the cathode side. The injected electrons and holes recombine in the EL layer 115, and the light-emitting substance contained in the EL layer 115 emits light.

[0064] When applying a white light-emitting element as the light-emitting element 120, it is preferable to adopt a structure in which the EL layer 115 contains two or more light-emitting substances. For example, white light emission can be obtained by selecting light-emitting substances such that the light emission of each of the two or more light-emitting substances is in a complementary color relationship. For example, it is preferable to include two or more of light-emitting substances that exhibit light emission such as R (red), G (green), B (blue), Y (yellow), O (orange), etc., or light-emitting substances that exhibit light emission including spectral components of two or more colors among R, G, and B. Also, it is preferable to apply a light-emitting element whose emission spectrum from the light-emitting element has two or more peaks within the wavelength range of the visible light region (for example, 350 nm to 750 nm). Further, the emission spectrum of a material having a peak in the yellow wavelength region is preferably a material that also has spectral components in the green and red wavelength regions.

[0065] The EL layer 115 preferably has a structure in which a light-emitting layer containing a light-emitting material that emits one color and a light-emitting layer containing a light-emitting material that emits another color are laminated. For example, the plurality of light-emitting layers in the EL layer 115 may be laminated in contact with each other, or may be laminated via a region that does not contain any light-emitting material. For example, a structure may be adopted in which a region containing the same material (for example, a host material, an assist material) as the fluorescent light-emitting layer or the phosphorescent light-emitting layer and not containing any light-emitting material is provided between the fluorescent light-emitting layer and the phosphorescent light-emitting layer. Thereby, the fabrication of the light-emitting element becomes easy, and the driving voltage is reduced.

[0066] Also, the light-emitting element 120 may be a single element having one EL layer, or may be a tandem element in which a plurality of EL layers are laminated via a charge generation layer.

[0067] The conductive film that can be used for the conductive layer 114 and the like and transmits visible light can be formed, for example, using indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide added with gallium, and the like. Also, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, alloys containing these metal materials, or nitrides of these metal materials (for example, titanium nitride) can also be used by forming them thinly enough to have light transmittance. Further, a laminated film of the above materials can be used as the conductive layer. For example, using a laminated film of an alloy of silver and magnesium and indium tin oxide is preferable because the conductivity can be enhanced. Also, graphene or the like may be used.

[0068] The conductive film that can be used for the reflective layer 112 and reflects visible light can be formed, for example, using metal materials such as aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or alloys containing these metal materials. Also, lanthanum, neodymium, or germanium may be added to the above metal materials or alloys. Also, an alloy containing titanium, nickel, or neodymium and aluminum (aluminum alloy) may be used. Also, an alloy containing copper, palladium, magnesium, and silver may be used. An alloy containing silver and copper is preferable because it has high heat resistance. Further, oxidation can be suppressed by laminating a metal film or a metal oxide film in contact with an aluminum film or an aluminum alloy film. Examples of the materials for such a metal film and metal oxide film include titanium or titanium oxide. Also, a film composed of the above conductive film that transmits visible light and a metal material may be laminated. For example, a laminated film of silver and indium tin oxide, a laminated film of an alloy of silver and magnesium and indium tin oxide, and the like can be used.

[0069] It is preferable to use a conductive film that reflects the visible light for the portion of the reflective layer 112 located on the EL layer 115 side. Further, it is preferable to laminate a conductive metal oxide film on the conductive film that reflects the visible light, since oxidation or corrosion of the conductive film that reflects the visible light can be suppressed.

[0070] As the insulating layer 113, it is preferable to use a material with high translucency. For example, inorganic insulating films such as silicon oxide film, silicon oxynitride film, aluminum oxide film, hafnium oxide film, etc. can be used either singly or in a laminated form. Also, by using a material with a high refractive index (e.g., 1.4 or more, preferably 1.5 or more) as the insulating layer 113, the physical thickness can be reduced, and productivity can be increased.

[0071] As the conductive film having translucency and reflectivity that can be used for the conductive layer 116, a film formed by making the conductive film that reflects the visible light thin enough for the visible light to pass through can be used. Also, by adopting a laminated structure of the said conductive film and the conductive film that transmits the visible light, conductivity or mechanical strength can be enhanced.

[0072] The conductive film having translucency and reflectivity preferably has a reflectance with respect to visible light (e.g., reflectance with respect to light of a predetermined wavelength within the range of 400 nm to 700 nm) of 20% or more and 80% or less, preferably 40% or more and 70% or less. Also, the reflectance of the conductive film having reflectivity with respect to visible light is preferably 40% or more and 100% or less, preferably 70% or more and 100% or less. Also, the reflectance of the conductive film having translucency with respect to visible light is preferably 0% or more and 40% or less, preferably 0% or more and 30% or less.

[0073] As the conductive layer 111 that functions as the lower electrode, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, alloys containing these metal materials, or nitrides of these metal materials (e.g., titanium nitride) etc. can be used. These can also be suitably used as the conductive film of the plug 130.

[0074] The electrodes constituting the light-emitting element may be formed using, for example, a vapor deposition method or a sputtering method. In addition, they can be formed using a discharge method such as an inkjet method, a printing method such as a screen printing method, or a plating method.

[0075] Note that the above-described light-emitting layer, and the layers containing a substance with high hole injection property, a substance with high hole transport property, a substance with high electron transport property, a substance with high electron injection property, a bipolar substance, etc. may each have an inorganic compound such as a quantum dot, or a polymer compound (oligomer, dendrimer, polymer, etc.). For example, by using quantum dots in the light-emitting layer, it can also function as a light-emitting material.

[0076] As the quantum dot material, a colloidal quantum dot material, an alloy-type quantum dot material, a core-shell type quantum dot material, a core type quantum dot material, etc. can be used. Also, a material containing an element group of Group 12 and Group 16, Group 13 and Group 15, or Group 14 and Group 16 may be used. Alternatively, a quantum dot material containing elements such as cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium, lead, gallium, arsenic, aluminum, etc. may be used.

[0077] It is preferable that the optical distance between the surface of the reflective layer 112 that reflects the visible light of each light-emitting element and the conductive layer 116 that has transmissivity and reflectivity with respect to the visible light is adjusted to be m×λ / 2 (m is a natural number) or in the vicinity thereof with respect to the wavelength λ of the light whose intensity is desired to be enhanced.

[0078] Note that the above-described optical distance is actually related to the product of the physical distance between the reflective surface of the reflective layer 112 and the reflective surface of the conductive layer 116 having transmissivity and reflectivity, and the refractive index of the layer provided therebetween. Therefore, it is difficult to precisely adjust the optical distance. For this reason, it is preferable to adjust the optical distance assuming the surfaces of the reflective layer 112 and the conductive layer 116 having transmissivity and reflectivity as the reflective surfaces, respectively.

[0079] [Manufacturing Method Example] An example of a method for manufacturing a display device according to an aspect of the present invention will be described with reference to the drawings.

[0080] Note that the thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an atomic layer deposition (ALD) method, or the like. Examples of the CVD method include a plasma enhanced CVD (PECVD) method and a thermal CVD method. Further, one of the thermal CVD methods is a metal organic CVD (MOCVD) method.

[0081] Also, the 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, slit coating, roll coating, curtain coating, and knife coating.

[0082] In addition, when processing the thin films constituting the display device, a photolithography method or the like can be used. Alternatively, the thin films may be processed using a nanoimprint method, a sandblast method, a lift-off method, or the like. Also, island-shaped thin films may be directly formed by a film formation method using a shielding mask such as a metal mask.

[0083] Typically, there are the following two methods as the photolithography method. One is a method in which a resist mask is formed on a thin film to be processed, the thin film is processed by etching or the like, and the resist mask is removed. The other is a method in which after forming a photosensitive thin film, exposure and development are performed to process the thin film into a desired shape.

[0084] In the photolithography method, as the light used for exposure, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or light obtained by mixing these can be used. In addition, ultraviolet light, KrF laser light, ArF laser light, etc. can also be used. Further, exposure may be performed by immersion lithography technology. Also, as the light used for exposure, extreme ultraviolet (EUV) light or X-rays may be used. Instead of the light used for exposure, an electron beam can also be used. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because extremely fine processing becomes possible. When performing exposure by scanning a beam such as an electron beam, a photomask is not required.

[0085] For etching the thin film, a dry etching method, a wet etching method, a sandblasting method, etc. can be used.

[0086] As the planarization treatment of the thin film, typically, a polishing treatment method such as a chemical mechanical polishing (CMP) method can be preferably used. In addition, a dry etching treatment or a plasma treatment may be used. Note that the polishing treatment, dry etching treatment, and plasma treatment may be performed multiple times, or they may be combined. Also, when combining them, the process order is not particularly limited, and it may be appropriately set according to the uneven state of the surface to be processed.

[0087] To accurately process the thin film so that it reaches the desired thickness, for example, the CMP method is used. In that case, first, polishing is performed at a constant processing speed until a part of the upper surface of the thin film is exposed. Then, by performing polishing under conditions with a slower processing speed until the thin film reaches the desired thickness, it becomes possible to perform high-precision processing.

[0088] As a method for detecting the end point of polishing, there are an optical method of irradiating light onto the surface of the surface to be processed and detecting the change in the reflected light, a physical method of detecting the change in the polishing resistance received by the processing apparatus from the surface to be processed, a method of applying magnetic field lines to the surface to be processed and using the change in the magnetic field lines due to the generated eddy current, and the like.

[0089] After the upper surface of the thin film is exposed, while monitoring the thickness of the thin film by an optical method using a laser interferometer or the like, a polishing process is performed under the condition of a slow processing speed, whereby the thickness of the thin film can be controlled with high precision. In addition, if necessary, the polishing process may be performed a plurality of times until the thin film reaches a desired thickness.

[0090] 〔Example of manufacturing method 1〕 Hereinafter, an example of a manufacturing method of a display device will be described by taking the display device 100E exemplified in the above configuration example as an example.

[0091] {Preparation of substrate 101} As the substrate 101, a substrate having heat resistance sufficient to withstand at least subsequent heat treatment can be used. Examples of the insulating substrate used for the substrate 101 include a glass substrate, a quartz substrate, a sapphire substrate, and a ceramic substrate. In addition, a single crystal semiconductor substrate, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, and a semiconductor substrate such as an SOI substrate made of silicon or silicon carbide can also be used.

[0092] In particular, as the substrate 101, it is preferable to use a substrate on which a semiconductor circuit including semiconductor elements such as transistors is formed on the semiconductor substrate or the insulating substrate. The semiconductor circuit preferably constitutes, for example, a pixel circuit, a gate line drive circuit (gate driver), a source line drive circuit (source driver), and the like. In addition to the above, an arithmetic circuit, a memory circuit, and the like may be configured.

[0093] In the present embodiment, a substrate on which at least a pixel circuit is configured is used as the substrate 101.

[0094] {Formation of Insulating Layer 121, Plug 131, and Conductive Layer 111} An insulating film serving as the insulating layer 121 is formed on the substrate 101. Subsequently, an opening reaching the substrate 101 is formed at the position of the insulating layer 121 where the plug 131 is to be formed. The opening preferably reaches an electrode or wiring provided on the substrate 101. Subsequently, after forming a conductive film so as to fill the opening, a planarization process is performed so that the upper surface of the insulating layer 121 is exposed. Thereby, the plug 131 embedded in the insulating layer 121 can be formed.

[0095] A conductive film is formed on the insulating layer 121 and the plug 131, and by leaving the portion overlapping the plug 131 and removing the unnecessary portions by etching, the conductive layer 111 electrically connected to the plug 131 is formed (FIG. 4A).

[0096] {Formation of Reflective Layer 112 and Insulating Layer 113} A conductive film 112f serving as the reflective layer 112 is formed covering the insulating layer 121 and the conductive layer 111. Subsequently, an insulating film 113f serving as the insulating layer 113 is formed on the conductive film 112f. Subsequently, a resist mask 151 is formed on the insulating film 113f (FIG. 4B). The resist mask 151 is formed in the portions that will later become the reflective layer 112 and the insulating layer 113. The resist mask 151 is preferably formed inside the end of the conductive layer 111. Thereafter, the conductive film 112f and the insulating film 113f not covered by the resist mask 151 are removed by etching, whereby the reflective layer 112 and the insulating layer 113 can be formed. After this, a heat treatment in an atmosphere containing oxygen, particularly a heat treatment in an air atmosphere (also referred to as an air bake), or a plasma treatment in an atmosphere containing oxygen (also referred to as ashing) may be performed to add a treatment for stabilizing (here, oxidizing) the ends of the insulating layer 113 or the reflective layer 112.

[0097] {Formation of Conductive Layers 114R, 114G, and 114B} On the conductive layer 111, the insulating layer 113, and the insulating layer 121, a conductive film 143f that will later become the conductive layer 143 is formed. Subsequently, a resist mask 152 is formed on the conductive film 143f (Fig. 4C). The resist mask 152 is formed in a portion that will later become the conductive layer 114R. Thereafter, the conductive layer 143 can be formed by etching the conductive film 143f not covered by the resist mask 152.

[0098] Subsequently, on the conductive layer 111, the insulating layer 113, the conductive layer 143, and the insulating layer 121, a conductive film 142f that will later become the conductive layer 142 is formed, and a resist mask 153 is formed on the conductive film 142f (Fig. 4D). The resist mask 153 is provided to cover the overlapping portion of the conductive layer 143 of the conductive film 142f and the portion that will later become the conductive layer 114G. Thereafter, the conductive layer 142 can be formed by etching the conductive film 142f in the same manner as above.

[0099] Subsequently, on the conductive layer 111, the insulating layer 113, the conductive layer 142, and the insulating layer 121, a conductive film 141f that will later become the conductive layer 141 is formed, and a resist mask 154 is formed on the conductive film 141f (Fig. 4E). The resist mask 154 is provided to cover the overlapping portion of the conductive layer 142 of the conductive film 141f and the portion that will later become the conductive layer 114B. Thereafter, the conductive layer 141 can be formed by etching the conductive film 141f in the same manner as above.

[0100] As described above, the conductive layer 114R, the conductive layer 114G, and the conductive layer 114B can be formed (Fig. 5A).

[0101] In FIG. 4C, the resist mask 152 is formed such that the end of the resist mask 152 covers the end of the conductive layer 111, but it may also be formed to coincide with the end of the reflective layer 112. The same applies to the positional relationship between the resist mask 153 and the reflective layer 112. Note that the end of the resist mask 154 is formed to coincide with the end of the conductive layer 111, or is formed to cover the end of the conductive layer 111. In this case, the shape of the conductive layer 143 to be formed is the shape shown in FIG. 5A that covers the end of the conductive layer 111. With such a configuration, the conductive layer 111 and the conductive layer 114 are electrically connected.

[0102] {Formation of Insulating Layer 117} Subsequently, an insulating film is formed to cover the conductive layer 141 and the insulating layer 121, and unnecessary portions are removed by etching to form an insulating layer 117 that covers the end of the conductive layer 141 (FIG. 5B). It is preferable that the end of the insulating layer 117 on the conductive layer 114 is processed to have a tapered shape. The taper angle (the angle formed between the surface to be formed and the end surface) of the end of the insulating layer 117 is preferably greater than 0 degrees and 60 degrees or less, more preferably 5 degrees or more and 45 degrees or less, and even more preferably 5 degrees or more and 30 degrees or less.

[0103] The insulating layer 117 can be formed of an organic insulating film or an inorganic insulating film. In particular, when a display device with ultra-high definition (for example, 2000 ppi or more) is used, it is preferable to use an inorganic insulating film.

[0104] {Formation of EL Layer 115 and Conductive Layer 116} Subsequently, an EL layer 115 and a conductive layer 116 are sequentially formed on the conductive layer 141 and the insulating layer 117 to form a light-emitting element 120 (FIG. 5C).

[0105] The EL layer 115 has a layer containing at least a light-emitting compound. In addition, a configuration in which an electron injection layer, an electron transport layer, a charge generation layer, a hole transport layer, and a hole injection layer are stacked may also be used. The EL layer 115 can be formed by, for example, a vapor deposition method or a liquid phase method such as an inkjet method.

[0106] The conductive layer 116 is formed to have transmissivity and reflectivity with respect to visible light. For example, a thin metal film or alloy film that transmits visible light can be used. Alternatively, a conductive film having translucency (for example, a metal oxide film) may be laminated on such a film.

[0107] As described above, the light-emitting elements 120R, 120G, and 120B having different optical distances can be formed.

[0108] According to the above manufacturing method example, since the difference in optical distance between each light-emitting element can be precisely controlled by the thickness of the conductive layer 114, color shift in each light-emitting element is less likely to occur, color reproducibility is excellent, and a display device with extremely high display quality can be easily manufactured.

[0109] Further, the light-emitting element 120 can be formed on an insulating layer whose upper surface is flattened. Furthermore, since the lower electrode (conductive layer 111) of the light-emitting element 120 can be electrically connected to a pixel circuit or the like of the substrate 101 via the plug 131, it is possible to configure extremely fine pixels and realize an extremely high-definition display device. In addition, since the light-emitting element 120 can be arranged overlapping with the pixel circuit or the driving circuit, a display device with a high aperture ratio (effective light-emitting area ratio) can be realized.

[0110] 〔Manufacturing Method Example 2〕 Hereinafter, a manufacturing method example of a display device will be described by taking the display device 100F illustrated in the above Configuration Example 1 as an example.

[0111] Note that hereinafter, parts overlapping with the above Manufacturing Method Example 1 may be incorporated and the description may be omitted.

[0112] {Preparation of Substrate 101} Similar to the above, a substrate on which at least a pixel circuit is configured is used as the substrate 101.

[0113] {Formation of Insulating Layer 121 and Plug 131} Subsequently, an insulating layer 121 and a plug 131 are formed. The insulating layer 121 and the plug 131 can be formed by the same method as described above.

[0114] {Film formation of conductive layer 111, reflective layer 112, and insulating layer 113} A conductive film 111f that becomes the conductive layer 111, a conductive film 112f that becomes the reflective layer 112, and an insulating film 113f that becomes the insulating layer 113 are formed in this order on the insulating layer 121 and on the plug 131 (FIG. 6A).

[0115] {Formation of plug 130} Openings that reach the conductive film 111f are formed at the positions where the plug 130 is to be formed in the conductive film 112f and the insulating film 113f (FIG. 6B). In FIG. 6B, the conductive film 112f and the insulating film 113f are etched to form the openings, but the insulating film 113f may be etched to form openings that reach the conductive film 112f. Subsequently, a conductive film 130f that will later become the plug 130 is formed so as to fill the openings (FIG. 6C).

[0116] Thereafter, a planarization process is performed until the upper surface of the insulating film 113f is exposed, and an insulating film 113f with a planarized upper surface and a plug 130 embedded in the insulating film 113f and the conductive film 112f can be formed (FIG. 6D).

[0117] At this time, due to the influence of the uneven shape of the upper surface of the insulating film 113f, a part of the conductive film 130f may remain on the upper surface of the insulating film 113f after the planarization process. Therefore, the insulating film 113f is formed to be sufficiently thick in advance, and from the time when the upper surface of the insulating film 113f is exposed during the planarization process, additional processing is performed to preferably remove the remaining film of the conductive film 130f.

[0118] {Formation of conductive layer 114R, conductive layer 114G, and conductive layer 114B} First, a conductive film 143f that becomes the conductive layer 143 is formed to cover the insulating film 113f and the plug 130. Subsequently, a resist mask 155 is formed on the conductive film 143f (FIG. 6E). The resist mask 155 is formed in a portion that will later become the conductive layer 114R. Thereafter, the conductive layer 143 can be formed by etching the conductive film 143f not covered by the resist mask 155.

[0119] Subsequently, a conductive film 142f that becomes the conductive layer 142 is formed to cover the insulating film 113f and the conductive layer 143, and a resist mask 156 is formed on the conductive film 142f (FIG. 7A). The resist mask 156 is provided to cover the overlapping portion of the conductive layer 143 of the conductive film 142f and the portion that will later become the conductive layer 114G. Thereafter, the conductive layer 142 can be formed by etching the conductive film 142f in the same manner as above.

[0120] Subsequently, a conductive film 141f that becomes the conductive layer 141 is formed to cover the insulating film 113f and the conductive layer 142, and a resist mask 157 is formed on the conductive film 141f (FIG. 7B). The resist mask 157 is provided to cover the overlapping portion of the conductive layer 142 of the conductive film 141f and the portion that will later become the conductive layer 114B. Thereafter, the conductive layer 141, the conductive layer 111, the reflective layer 112, and the insulating layer 113 can be formed by etching the conductive film 141f, the conductive layer 142, the conductive layer 143, the conductive film 111f, the conductive film 112f, and the insulating film 113f not covered by the resist mask 157.

[0121] Thus, the conductive layer 114R, the conductive layer 114G, the conductive layer 114B, the conductive layer 111, the reflective layer 112, and the insulating layer 113 can be formed (FIG. 7C).

[0122] {Formation of Insulating Layer 117} Subsequently, an insulating film is formed to cover the conductive layer 114R, the conductive layer 114G, the conductive layer 114B, the insulating layer 113, the reflective layer 112, the conductive layer 111, and the insulating layer 121, and unnecessary portions are removed by etching to form an insulating layer 117 that covers the ends of the conductive layer 114R, the conductive layer 114G, the conductive layer 114B, the insulating layer 113, the reflective layer 112, and the conductive layer 111 (Fig. 7D). It is preferable that the end portion of the insulating layer 117 on the conductive layer 114 is processed to have a tapered shape. The taper angle (the angle formed by the surface to be formed and the end face) of the end portion of the insulating layer 117 is preferably greater than 0 degrees and 60 degrees or less, more preferably 5 degrees or more and 45 degrees or less, and even more preferably 5 degrees or more and 30 degrees or less.

[0123] The insulating layer 117 can be formed of an organic insulating film or an inorganic insulating film. In particular, when a display device with ultra-high definition (for example, 2000 ppi or more) is used, it is preferable to use an inorganic insulating film.

[0124] {Formation of EL layer 115 and conductive layer 116} Subsequently, an EL layer 115 and a conductive layer 116 are sequentially formed on the conductive layer 141 and the insulating layer 117 to form a light-emitting element 120 (Fig. 7E). The light-emitting elements 120R, 120G, and 120B with different optical distances can be formed by the same method as described above.

[0125] According to the above manufacturing method example, a display device with extremely high display quality can be easily manufactured.

[0126] In addition, the light-emitting element 120 can be formed on an insulating layer with a flattened upper surface. Also, the light-emitting element 120 is configured to be electrically connected to the conductive layer 114 and the lower electrode (conductive layer 111) via a plug 130 in the light-emitting element. Furthermore, since the lower electrode of the light-emitting element 120 can be configured to be electrically connected to a pixel circuit or the like of the substrate 101 via a plug 131, it is possible to form extremely fine pixels and realize an extremely high-definition display device. Also, since the light-emitting element 120 can be arranged overlapping a pixel circuit or a driving circuit, a display device with a high aperture ratio (effective light-emitting area ratio) can be realized.

[0127] [Modification Example] Hereinafter, a modification example in which a part of the configuration is different from the above display device will be described.

[0128] FIG. 8A is a schematic cross-sectional view of the display device 100G. The display device 100G is mainly different from the above display device 100A in that the shapes of the EL layer 115 and the conductive layer 116 are different and that it has an insulating layer 118.

[0129] In the display device 100G, the EL layer 115 and the conductive layer 116 are separated between adjacent light-emitting elements of different colors. Thereby, it is possible to prevent the current (also referred to as leakage current) flowing through the EL layer 115 between adjacent light-emitting elements of different colors. Therefore, the light emission caused by the leakage current can be suppressed, and a display with high contrast can be realized. Further, even when the fineness is increased, a material with high conductivity can be used for the EL layer 115, so that the range of material selection can be widened, and it becomes easy to improve efficiency, reduce power consumption, and improve reliability.

[0130] The EL layer 115 and the conductive layer 116 may form an island-shaped pattern by film formation using a shadow mask such as a metal mask, but it is particularly preferable to use a processing method that does not use a metal mask. Thereby, since it becomes possible to form an extremely fine pattern, the fineness and the aperture ratio can be improved as compared with the formation method using a metal mask. As such a processing method, typically, a photolithography method can be used. In addition, formation methods such as a nanoimprint method and a sandblast method can also be used.

[0131] In this specification and the like, a device using a metal mask or an FMM (fine metal mask, high-definition metal mask) may be referred to as an MM (metal mask) structure. Also, in this specification and the like, a device that does not use a metal mask or an FMM may be referred to as an MML (metal maskless) structure.

[0132] As a method for manufacturing the display device 100G, first, the EL layer 115 and the conductive layer 116 are formed without using a metal mask, and then a resist mask is formed on the conductive layer 116. Then, a part of the EL layer 115 and the conductive layer 116 not covered by the resist mask is removed by etching, and then the resist mask is removed. And the insulating layer 118 is formed. Thereby, the display device 100G can be manufactured.

[0133] Also, in the display device 100G, an insulating layer 118 is provided so as to cover the light-emitting element 120B, the light-emitting element 120G, and the light-emitting element 120R. Between adjacent light-emitting elements, a part of the insulating layer 118 is in contact with the upper surface of the insulating layer 117. The insulating layer 118 functions as a protective layer that prevents impurities such as water from diffusing into the light-emitting element. It is preferable to use an inorganic insulating film with low moisture permeability, such as a silicon oxide film, a silicon nitride film, or an aluminum oxide film, for the insulating layer 118.

[0134] Also, the display device 100H shown in FIG. 8B is an example in the case where the EL layer 115 and the conductive layer 116 of the display device 100C are processed.

[0135] In the display device 100G and the display device 100H, it is preferable that the EL layer 115 and the conductive layer 116 are processed so as to be continuous without being divided between pixels having the same color. For example, the EL layer 115 and the conductive layer 116 can be processed in a stripe shape. Thereby, a predetermined potential can be applied without the conductive layer 116 of all the light-emitting elements being in a floating state.

[0136] The above is the description of the modified example.

[0137] [Configuration Example 2] Hereinafter, a more specific example of a display device having a transistor will be described.

[0138] [Configuration Example 2-1] FIG. 9 is a schematic cross-sectional view of the display device 200A.

[0139] The display device 200A includes a substrate 201, a light-emitting element 120R, a light-emitting element 120G, a light-emitting element 120B, a capacitor element 240, a transistor 210, and the like.

[0140] The stacked structure from the substrate 201 to the capacitor element 240 corresponds to the substrate 101 in the above-described Configuration Example 1.

[0141] The transistor 210 is a transistor in which a channel region is formed on the substrate 201. As the substrate 201, for example, a semiconductor substrate such as a single crystal silicon substrate can be used. The transistor 210 includes a part of the substrate 201, a conductive layer 211, a low-resistance region 212, an insulating layer 213, an insulating layer 214, and the like. The conductive layer 211 functions as a gate electrode. The insulating layer 213 is located between the substrate 201 and the conductive layer 211 and functions as a gate insulating layer. The low-resistance region 212 is a region in which the substrate 201 is doped with impurities and functions as one of a source or a drain. The insulating layer 214 is provided to cover the side surface of the conductive layer 211 and functions as an insulating layer.

[0142] Also, an element isolation layer 215 is provided between two adjacent transistors 210 so as to be embedded in the substrate 201.

[0143] Also, an insulating layer 261 is provided to cover the transistor 210, and a capacitor element 240 is provided on the insulating layer 261.

[0144] The capacitor element 240 includes a conductive layer 241, a conductive layer 242, and an insulating layer 243 located between them. The conductive layer 241 functions as one electrode of the capacitor element 240, the conductive layer 242 functions as the other electrode of the capacitor element 240, and the insulating layer 243 functions as a dielectric of the capacitor element 240.

[0145] The conductive layer 241 is provided on the insulating layer 261 and is electrically connected to one of the source or drain of the transistor 210 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 242 is provided in a region overlapping the conductive layer 241 via the insulating layer 243.

[0146] An insulating layer 121 is provided to cover the capacitor element 240, and light-emitting elements 120R, 120G, 120B, etc. are provided on the insulating layer 121. Here, as the configurations of the light-emitting elements 120R, 120G, and 120B, an example using the configurations exemplified in Configuration Examples 1-3 and FIG. 3A is shown, but it is not limited thereto, and various configurations exemplified above can be applied.

[0147] In the display device 200A, an insulating layer 161, an insulating layer 162, and an insulating layer 163 are provided in this order so as to cover the conductive layer 116 of the light-emitting element 120. These three insulating layers function as a protective layer that prevents impurities such as water from diffusing into the light-emitting element 120. It is preferable to use an inorganic insulating film with low moisture permeability, such as a silicon oxide film, a silicon nitride film, or an aluminum oxide film, for the insulating layer 161 and the insulating layer 163. Also, an organic insulating film with high light transmittance can be used for the insulating layer 162. By using an organic insulating film for the insulating layer 162, the influence of the uneven shape below the insulating layer 162 can be mitigated, and the surface to be formed of the insulating layer 163 can be made smooth. As a result, defects such as pinholes are less likely to occur in the insulating layer 163, so that the moisture permeability of the protective layer can be further increased. Note that the configuration of the protective layer covering the light-emitting element 120 is not limited to this, and it may have a single-layer or two-layer structure, or a laminated structure of four or more layers.

[0148] On the insulating layer 163, a colored layer 165R overlapping the light-emitting element 120R, a colored layer 165G overlapping the light-emitting element 120G, and a colored layer 165B overlapping the light-emitting element 120B are provided. For example, the colored layer 165R transmits red light, the colored layer 165G transmits green light, and the colored layer 165B transmits blue light. Thereby, the color purity of the light from each light-emitting element can be enhanced, and a display device with higher display quality can be realized. Further, by forming each colored layer on the insulating layer 163, alignment between each light-emitting unit and each colored layer is easier compared to the case where the colored layer is formed on the substrate 202 described later, and a display device with extremely high definition can be realized.

[0149] The display device 200A has a substrate 202 on the viewing side. The substrate 202 and the substrate 201 are bonded together by a light-transmissive adhesive layer 164. As the substrate 202, a light-transmissive substrate such as a glass substrate, a quartz substrate, a sapphire substrate, or a plastic substrate can be used.

[0150] With such a configuration, a display device with extremely high definition and high display quality can be realized.

[0151] 〔Configuration Example 2-2〕 FIG. 10 is a schematic cross-sectional view of the display device 200B. The display device 200B mainly differs from the above-described display device 200A in that the configuration of the transistor is different.

[0152] The transistor 220 is a transistor in which a metal oxide (also referred to as an oxide semiconductor) is applied to a semiconductor layer in which a channel is formed.

[0153] The transistor 220 includes a semiconductor layer 221, an insulating layer 223, a conductive layer 224, a pair of conductive layers 225, an insulating layer 226, a conductive layer 227, and the like.

[0154] As the substrate 201 on which the transistor 220 is provided, the above-described insulating substrate or semiconductor substrate can be used.

[0155] An insulating layer 232 is provided on a substrate 201. The insulating layer 232 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 201 into the transistor 220, and prevents oxygen from desorbing from the semiconductor layer 221 to the insulating layer 232 side. As the insulating layer 232, a film in which hydrogen or oxygen diffuses less easily than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film, can be used.

[0156] A conductive layer 227 is provided on the insulating layer 232, and an insulating layer 226 is provided to cover the conductive layer 227. The conductive layer 227 functions as a first gate electrode of the transistor 220, and a part of the insulating layer 226 functions as a first gate insulating layer. It is preferable to use an oxide insulating film such as a silicon oxide film for at least a portion of the insulating layer 226 that contacts the semiconductor layer 221. The upper surface of the insulating layer 226 is preferably planarized.

[0157] The semiconductor layer 221 is provided on the insulating layer 226. The semiconductor layer 221 preferably has a metal oxide (also referred to as an oxide semiconductor) film having semiconductor characteristics. Details of materials that can be suitably used for the semiconductor layer 221 will be described later.

[0158] A pair of conductive layers 225 are provided in contact with the semiconductor layer 221 and function as source and drain electrodes.

[0159] Also, an insulating layer 228 is provided to cover the upper and side surfaces of the pair of conductive layers 225 and the side surface of the semiconductor layer 221, etc., and an insulating layer 261b is provided on the insulating layer 228. The insulating layer 228 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 261b, etc. into the semiconductor layer 221, and prevents oxygen from desorbing from the semiconductor layer 221. As the insulating layer 228, the same insulating film as the insulating layer 232 described above can be used.

[0160] An opening reaching the semiconductor layer 221 is provided in the insulating layer 228 and the insulating layer 261b. Inside the opening, an insulating layer 223 in contact with the side surfaces of the insulating layer 261b, the insulating layer 228, and the conductive layer 225, and the upper surface of the semiconductor layer 221, and a conductive layer 224 are embedded. The conductive layer 224 functions as a second gate electrode, and the insulating layer 223 functions as a second gate insulating layer.

[0161] The upper surfaces of the conductive layer 224, the insulating layer 223, and the insulating layer 261b are planarized so that their heights are substantially the same, and an insulating layer 229 and an insulating layer 261a are provided to cover them.

[0162] The insulating layer 261a and the insulating layer 261b function as an interlayer insulating layer. Further, the insulating layer 229 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 261a or the like into the transistor 220. As the insulating layer 229, the same insulating film as the insulating layer 228 and the insulating layer 232 can be used.

[0163] A plug 271 electrically connected to one of the pair of conductive layers 225 is provided so as to be embedded in the insulating layer 261a, the insulating layer 229, and the insulating layer 261b. Here, the plug 271 preferably has a conductive layer 271a covering the side surfaces of the respective openings of the insulating layer 261a, the insulating layer 261b, the insulating layer 229, and the insulating layer 228, and a part of the upper surface of the conductive layer 225, and a conductive layer 271b in contact with the upper surface of the conductive layer 271a. At this time, it is preferable to use a conductive material in which hydrogen and oxygen hardly diffuse as the conductive layer 271a.

[0164] 〔Configuration Example 2-3〕 FIG. 11 is a schematic cross-sectional view of the display device 200C. The display device 200C has a configuration in which a transistor 210 in which a channel is formed on a substrate 201 and a transistor 220 in which a semiconductor layer in which a channel is formed contains a metal oxide are stacked.

[0165] An insulating layer 261 is provided to cover the transistor 210, and a conductive layer 251 is provided on the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided on the insulating layer 262. The conductive layer 251 and the conductive layer 252 each function as a wiring. Further, an insulating layer 263 and an insulating layer 232 are provided to cover the conductive layer 252, and a transistor 220 is provided on the insulating layer 232. An insulating layer 265 is provided to cover the transistor 220, and a capacitor element 240 is provided on the insulating layer 265. The capacitor element 240 and the transistor 220 are electrically connected by a plug 274.

[0166] The transistor 220 can be used as a transistor constituting a pixel circuit. Further, the transistor 210 can be used as a transistor constituting a pixel circuit or a transistor constituting a driving circuit (gate line driving circuit, source line driving circuit) for driving the pixel circuit. Further, the transistor 210 and the transistor 220 can be used as transistors constituting various circuits such as an arithmetic circuit or a memory circuit.

[0167] With such a configuration, not only a pixel circuit but also a driving circuit or the like can be formed directly under the light emitting unit, so that the display device can be miniaturized as compared with the case where a driving circuit is provided around the display area.

[0168] 〔Configuration Example 2-4〕 FIG. 12 is a schematic cross-sectional view of the display device 200D. The display device 200D is mainly different from the display device 200C in that two transistors to which an oxide semiconductor is applied are stacked.

[0169] The display device 200D has a transistor 230 between the transistor 210 and the transistor 220. The transistor 230 has the same configuration as the transistor 220 except that it does not have a first gate electrode. Note that the transistor 230 may be configured to have a first gate electrode.

[0170] An insulating layer 263 and an insulating layer 231 are provided to cover the conductive layer 252, and a transistor 230 is provided on the insulating layer 231. The transistor 230 and the conductive layer 252 are electrically connected via a plug 273, a conductive layer 253, and a plug 272. Further, an insulating layer 264 and an insulating layer 232 are provided to cover the conductive layer 253, and a transistor 220 is provided on the insulating layer 232.

[0171] For example, the transistor 220 functions as a transistor for controlling the current flowing through the light-emitting element 120. Further, the transistor 230 functions as a selection transistor for controlling the selection state of the pixel. Further, the transistor 210 functions as a transistor constituting a driving circuit for driving the pixel.

[0172] In this way, by stacking three or more layers in which transistors are formed, the occupied area of the pixel can be further reduced, and a high-definition display device can be realized.

[0173] Hereinafter, components such as transistors applicable to the display device will be described.

[0174] 〔Transistor〕 The transistor has a conductive layer that functions as a gate electrode, a semiconductor layer, a conductive layer that functions as a source electrode, a conductive layer that functions as a drain electrode, and an insulating layer that functions as a gate insulating layer.

[0175] Note that the structure of the transistor included in the display device according to one embodiment of the present invention is not particularly limited. For example, it may be a planar transistor, a staggered transistor, or an inverse staggered transistor. Further, it may have any transistor structure of a top gate type or a bottom gate type. Alternatively, gate electrodes may be provided above and below the channel.

[0176] The crystallinity of the semiconductor material used for the transistor is not particularly limited, and any of an amorphous semiconductor, a single-crystalline semiconductor, or a semiconductor having crystallinity other than single crystals (microcrystalline semiconductor, polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. Using a single-crystalline semiconductor or a semiconductor having crystallinity is preferable because deterioration of transistor characteristics can be suppressed.

[0177] Hereinafter, a transistor using a metal oxide film particularly for a semiconductor layer where a channel is formed will be described.

[0178] As the semiconductor material used for the transistor, a metal oxide having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can be used. Typically, it is a metal oxide containing indium, etc., and for example, CAC-OS described later can be used.

[0179] In a transistor using a metal oxide having a wider band gap and a smaller carrier density than silicon, due to its low off-current, it is possible to hold the charge accumulated in a capacitive element connected in series with the transistor over a long period of time.

[0180] The semiconductor layer can be a film represented by an In-M-Zn-based oxide containing, for example, indium, zinc, and M (M is a metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium).

[0181] When the metal oxide constituting the semiconductor layer is an In-M-Zn-based oxide, the atomic ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide preferably satisfies In≧M and Zn≧M. As such atomic ratios of the metal elements of the sputtering target, In:M:Zn = 1:1:1, In:M:Zn = 1:1:1.2, In:M:Zn = 3:1:2, In:M:Zn = 4:2:3, In:M:Zn = 4:2:4.1, In:M:Zn = 5:1:6, In:M:Zn = 5:1:7, In:M:Zn = 5:1:8, etc. are preferable. Note that the atomic ratio of the semiconductor layer formed includes fluctuations of plus or minus 40% of the atomic ratio of the metal elements contained in the above sputtering target.

[0182] As the semiconductor layer, a metal oxide film with a low carrier density is used. For example, the carrier density of the semiconductor layer is 1×10 17 / cm 3 or less, preferably 1×10 15 / cm 3 or less, more preferably 1×10 13 / cm 3 or less, even more preferably 1×10 11 / cm 3 or less, still more preferably 1×10 10 / cm 3 less than, and metal oxides with a carrier density of 1×10 -9 / cm 3 or more can be used. Such metal oxides are called high-purity intrinsic or substantially high-purity intrinsic metal oxides. It can be said that the oxide semiconductor has a low defect level density and stable characteristics.

[0183] Note that the present invention is not limited to these, and an oxide semiconductor with an appropriate composition may be used according to the required semiconductor characteristics and electrical characteristics (field-effect mobility, threshold voltage, etc.) of the transistor. Further, in order to obtain the required semiconductor characteristics of the transistor, it is preferable to make the carrier density, impurity concentration, defect density, atomic ratio of metal elements and oxygen, interatomic distance, density, etc. of the semiconductor layer appropriate.

[0184] In a metal oxide constituting a semiconductor layer, when silicon or carbon, which is one of the Group 14 elements, is included, oxygen deficiency increases in the semiconductor layer and it becomes n-type. For this reason, the concentration of silicon or carbon in the semiconductor layer (the concentration obtained by secondary ion mass spectrometry) is set to 2×10 18 atoms / cm 3 or less, preferably 2×10 17 atoms / cm 3 or less.

[0185] In addition, when an alkali metal or an alkaline earth metal binds to a metal oxide, carriers may be generated, and the off-current of the transistor may increase. For this reason, the concentration of the alkali metal or alkaline earth metal obtained by secondary ion mass spectrometry in the semiconductor layer is set to 1×10 18 atoms / cm 3 or less, preferably 2×10 16 atoms / cm 3 or less.

[0186] In addition, when nitrogen is included in the metal oxide constituting the semiconductor layer, electrons as carriers are generated, the carrier density increases, and it easily becomes n-type. As a result, a transistor using a metal oxide containing nitrogen tends to have normally-on characteristics. For this reason, the nitrogen concentration obtained by secondary ion mass spectrometry in the semiconductor layer is preferably set to 5×10 18 atoms / cm 3 or less.

[0187] Oxide semiconductors are classified into single-crystalline oxide semiconductors and non-single-crystalline oxide semiconductors. Examples of non-single-crystalline oxide semiconductors include CAAC-OS (c-axis-aligned crystalline oxide semiconductor), polycrystalline oxide semiconductors, nc-OS (nanocrystalline oxide semiconductor), pseudo-amorphous oxide semiconductors (a-like OS: amorphous-like oxide semiconductor), and amorphous oxide semiconductors.

[0188] In addition, CAC-OS (cloud-aligned composite oxide semiconductor) may be used for the semiconductor layer of the transistor disclosed in one aspect of the present invention.

[0189] Note that the semiconductor layer of the transistor disclosed in one aspect of the present invention can preferably use the above-described non-single crystal oxide semiconductor. Further, as the non-single crystal oxide semiconductor, nc-OS or CAAC-OS can be preferably used.

[0190] Note that in one aspect of the present invention, it is preferable to use CAC-OS as the semiconductor layer of the transistor. By using CAC-OS, high electrical characteristics or high reliability can be imparted to the transistor.

[0191] Note that the semiconductor layer may be a mixed film having two or more of a CAAC-OS region, a polycrystalline oxide semiconductor region, an nc-OS region, a pseudo-amorphous oxide semiconductor region, and an amorphous oxide semiconductor region. The mixed film may have, for example, a single-layer structure or a stacked structure including any two or more of the above-described regions.

[0192] <Configuration of CAC-OS> Hereinafter, the configuration of CAC-OS that can be used for the transistor disclosed in one aspect of the present invention will be described.

[0193] CAC-OS is, for example, a configuration of a material in which elements constituting a metal oxide are unevenly distributed in a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less, or in the vicinity thereof. Hereinafter, in the metal oxide, one or more metal elements are unevenly distributed, and a region having the metal element is in a state of being mixed in a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less, or in the vicinity thereof, which is also referred to as a mosaic state or a patch state.

[0194] The metal oxide preferably contains at least indium. Particularly preferably, it contains indium and zinc. In addition to these, one or more selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium may also be included.

[0195] For example, in the In-Ga-Zn oxide, CAC-OS (among CAC-OS, the In-Ga-Zn oxide may be particularly referred to as CAC-IGZO.) refers to indium oxide (hereinafter, InO X1 (where X1 is a real number greater than 0).), or indium zinc oxide (hereinafter, In X2 Zn Y2 O Z2 (where X2, Y2, and Z2 are real numbers greater than 0).), and gallium oxide (hereinafter, GaO X3 (where X3 is a real number greater than 0).), or gallium zinc oxide (hereinafter, Ga X4 Zn Y4 O Z4 (where X4, Y4, and Z4 are real numbers greater than 0).) and other materials are separated to form a mosaic shape, and the mosaic-shaped InO X1 , or In X2 Zn Y2 O Z2 is distributed uniformly in the film (hereinafter, also referred to as a cloud-like state).

[0196] That is, CAC-OS is a composite metal oxide having a structure in which a region mainly composed of GaO X3 and a region mainly composed of In X2 Zn Y2 O Z2 , or InO X1 are mixed. In this specification, for example, when the atomic ratio of indium to the element M in the first region is greater than the atomic ratio of indium to the element M in the second region, it is considered that the concentration of indium in the first region is higher than that in the second region.

[0197] Note that IGZO is a common name and may refer to a single compound of In, Ga, Zn, and O. As a representative example, InGaO3(ZnO) m1 (m1 is a natural number), or In (1+x0) Ga (1-x0) O3(ZnO) m0 (-1 ≤ x0 ≤ 1, m0 is an arbitrary number). Examples of crystalline compounds represented by this formula include those having a single crystal structure, a polycrystalline structure, or a CAAC structure.

[0198] The above crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. Note that the CAAC structure is a crystal structure in which a plurality of IGZO nanocrystals have c-axis orientation and are connected without orientation in the a-b plane.

[0199] On the other hand, CAC-OS relates to the material composition of metal oxides. CAC-OS refers to a structure in which regions observed as nanoparticle-like regions mainly composed of Ga and regions observed as nanoparticle-like regions mainly composed of In are randomly dispersed in a mosaic pattern in a material composition containing In, Ga, Zn, and O. Therefore, in CAC-OS, the crystal structure is a secondary element.

[0200] Note that CAC-OS does not include a laminated structure of two or more types of films having different compositions. For example, a structure composed of two layers, a film mainly composed of In and a film mainly composed of Ga, is not included.

[0201] Note that there may be cases where no clear boundary can be observed between the region where GaO X3 is the main component and the region where In X2 Zn Y2 O Z2 , or InO X1 is the main component.

[0202] In addition, when one or more selected from aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium are included instead of gallium, CAC-OS refers to a structure in which regions observed as nanoparticles mainly composed of the metal element and regions observed as nanoparticles mainly composed of In are randomly dispersed in a mosaic pattern, respectively.

[0203] CAC-OS can be formed by a sputtering method, for example, under conditions where the substrate is not heated. Also, when forming CAC-OS by the sputtering method, any one or more selected from inert gases (typically argon), oxygen gas, and nitrogen gas can be used as the film-forming gas. Further, the lower the flow rate ratio of oxygen gas to the total flow rate of the film-forming gas during film formation, the more preferable it is. For example, it is preferable to set the flow rate ratio of oxygen gas to 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0204] CAC-OS has the characteristic that no distinct peak is observed when measured using θ / 2θ scan by the Out-of-plane method, which is one of the X-ray diffraction (XRD) measurement methods. That is, it can be seen from the X-ray diffraction measurement that there is no orientation in the a-b plane direction and the c-axis direction of the measurement region.

[0205] Also, in the electron diffraction pattern obtained by irradiating an electron beam with a probe diameter of 1 nm (also referred to as a nano-beam electron beam), a bright ring-shaped region and a plurality of bright spots within the ring-shaped region are observed. Therefore, it can be seen from the electron diffraction pattern that the crystal structure of CAC-OS has an nc (nano-crystal) structure without orientation in the plane direction and the cross-sectional direction.

[0206] For example, in the case of CAC-OS in In-Ga-Zn oxide, according to the EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX), GaO X3 regions where is the main component and In X2 Zn Y2 O Z2 or regions where InO X1 is the main component are unevenly distributed and mixed, and it can be confirmed that they have a structure.

[0207] CAC-OS has a different structure from the IGZO compound in which metal elements are uniformly distributed and has different properties from the IGZO compound. That is, CAC-OS has a structure in which regions where GaO X3 etc. are the main components and regions where In X2 Zn Y2 O Z2 or regions where InO X1 is the main component are phase-separated from each other, and regions with each element as the main component have a mosaic-like structure.

[0208] Here, regions where In X2 Zn Y2 O Z2 or regions where InO X1 is the main component are regions with higher conductivity compared to regions where GaO X3 etc. are the main components. That is, when carriers flow through regions where In X2 Zn Y2 O Z2 or regions where InO X1 is the main component, conductivity as a metal oxide is exhibited. Therefore, when regions where In X2 Zn Y2 O Z2 or regions where InO X1 is the main component are distributed in a cloud-like manner in the metal oxide, high field-effect mobility (μ) can be realized.

[0209] On the other hand, regions where GaO X3 etc. are the main components are In X2 Zn Y2 O Z2 or regions where InOX1 It is a region with high insulation compared to the region where [substance] is the main component. That is, by distributing regions where [substance] such as GaO X3 is the main component in the metal oxide, leakage current can be suppressed and good switching operation can be realized.

[0210] Therefore, when CAC-OS is used in a semiconductor device, the insulation property caused by GaO X3 etc. and the conductivity caused by In X2 Zn Y2 O Z2 or InO X1 act complementarily, enabling a high on-current (I on ) and a high field-effect mobility (μ) to be realized.

[0211] Also, a semiconductor device using CAC-OS has high reliability. Therefore, CAC-OS is optimal for various semiconductor devices including displays.

[0212] In addition, a transistor having CAC-OS in the semiconductor layer has a high field-effect mobility and a high driving ability. Therefore, by using such a transistor in a driving circuit, typically a scanning line driving circuit that generates a gate signal, a display device with a narrow border width (also referred to as a narrow border) can be provided. Also, by using such a transistor in a signal line driving circuit of a display device (especially a demultiplexer connected to the output terminal of a shift register included in the signal line driving circuit), a display device with a small number of wirings connected to the display device can be provided.

[0213] In addition, a transistor having CAC-OS in the semiconductor layer does not require a laser crystallization process such as that of a transistor using low-temperature polysilicon. Therefore, even in a display device using a large-area substrate, the manufacturing cost can be reduced. Furthermore, in a high-resolution and large-sized display device such as ultra-high vision ("4K resolution", "4K2K", "4K") or super-high vision ("8K resolution", "8K4K", "8K"), by using a transistor having CAC-OS in the semiconductor layer for the drive circuit and the display section, writing can be performed in a short time and display defects can be reduced, which is preferable.

[0214] Alternatively, silicon may be used for the semiconductor in which the channel of the transistor is formed. Although amorphous silicon may be used as the silicon, it is particularly preferable to use crystalline silicon. For example, it is preferable to use microcrystalline silicon, polycrystalline silicon, single-crystalline silicon, or the like. In particular, polycrystalline silicon can be formed at a lower temperature than single-crystalline silicon and has a higher field-effect mobility and higher reliability than amorphous silicon.

[0215] 〔Conductive layer〕 In addition to the gate, source, and drain of a transistor, materials that can be used for conductive layers such as various wirings and electrodes constituting a display device include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or alloys having these as a main component. Further, a film containing these materials can be used as a single layer or in a laminated structure. For example, a single layer structure of an aluminum film containing silicon, a two-layer structure in which an aluminum film is laminated on a titanium film, a two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, a two-layer structure in which a copper film is laminated on a tungsten film, a three-layer structure in which a titanium film or a titanium nitride film is provided and an aluminum film or a copper film is laminated thereon, and further a titanium film or a titanium nitride film is formed thereon, a three-layer structure in which a molybdenum film or a molybdenum nitride film is provided and an aluminum film or a copper film is laminated thereon, and further a molybdenum film or a molybdenum nitride film is formed thereon, etc. In addition, oxides such as indium oxide, tin oxide, or zinc oxide may be used. Further, the use of copper containing manganese is preferable because the controllability of the shape by etching is enhanced.

[0216] [Insulating layer] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, resins having a siloxane bond such as silicone, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0217] In addition, in this specification, oxynitride refers to a material having a higher oxygen content than nitrogen in its composition, and nitride oxide refers to a material having a higher nitrogen content than oxygen in its composition. For example, when silicon oxynitride is described, it refers to a material having a higher oxygen content than nitrogen in its composition, and when silicon nitride oxide is described, it refers to a material having a higher nitrogen content than oxygen in its composition.

[0218] Further, it is preferable that the light-emitting element is provided between a pair of insulating films with low water permeability. This can suppress the intrusion of impurities such as water into the light-emitting element and suppress a decrease in the reliability of the device.

[0219] Examples of the insulating film with low water permeability include films containing nitrogen and silicon such as a silicon nitride film and a silicon oxynitride film, or films containing nitrogen and aluminum such as an aluminum nitride film. Further, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, etc. may also be used.

[0220] For example, the water vapor transmission rate of the insulating film with low water permeability is 1×10 -5 [g / (m 2 ·day)] or less, preferably 1×10 -6 [g / (m 2 ·day)] or less, more preferably 1×10 -7 [g / (m 2 ·day)] or less, still more preferably 1×10 -8 [g / (m 2 ·day)] or less.

[0221] [Configuration Example of Display Module] Hereinafter, a configuration example of a display module having a display device according to one aspect of the present invention will be described.

[0222] FIG. 13A is a perspective schematic view of a display module 280. The display module 280 includes a display device 200 and an FPC 290. As the display device 200, each display device (display devices 200A to 200D) exemplified in Configuration Example 2 above can be applied.

[0223] The display module 280 includes a substrate 201 and a substrate 202. Further, a display unit 281 is provided on the substrate 202 side. The display unit 281 is an area for displaying an image in the display module 280 and is an area where light from each pixel provided in a pixel unit 284 described later can be visually recognized.

[0224] FIG. 13B shows a perspective view schematically showing the configuration on the substrate 201 side. The substrate 201 has a configuration in which 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 laminated. Further, a terminal section 285 for connecting to the FPC 290 is provided in a portion that does not overlap with the pixel section 284 on the substrate 201. Also, the terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286 composed of a plurality of wirings.

[0225] The pixel section 284 has a plurality of pixels 284a arranged periodically. An enlarged view of one pixel 284a is shown on the right side of FIG. 13B. The pixel 284a has a light-emitting element 120R, a light-emitting element 120G, and a light-emitting element 120B.

[0226] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically. The plurality of pixel circuits 283a may be arranged in a delta arrangement as shown in FIG. 13B. Since the delta arrangement can arrange pixel circuits at high density, a high-definition display device can be provided.

[0227] One pixel circuit 283a is a circuit that controls the light emission of the three light-emitting elements included in one pixel 284a. One pixel circuit 283a may be configured to include three circuits that control the light emission of one light-emitting element. For example, the pixel circuit 283a can be configured to include at least one selection transistor, one current control transistor (driving transistor), and a capacitive element for each light-emitting element. At this time, a gate signal is input to the gate of the selection transistor, and a source signal is input to one of the source or drain. Thereby, an active matrix type display device is realized.

[0228] The circuit section 282 has a circuit that drives each pixel circuit 283a of the pixel circuit section 283. For example, it preferably has a gate line driving circuit, a source line driving circuit, etc. In addition, it may have an arithmetic circuit, a memory circuit, a power supply circuit, etc.

[0229] The FPC 290 functions as a wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit section 282. Also, an IC may be mounted on the FPC 290.

[0230] The display module 280 can have a configuration in which a pixel circuit section 283, a circuit section 282, or the like is laminated below the pixel section 284. Therefore, the aperture ratio (effective display area ratio) of the display section 281 can be made extremely high. For example, the aperture ratio of the display section 281 can be 40% or more and less than 100%, preferably 50% or more and 95% or less, more preferably 60% or more and 95% or less. Also, the pixels 284a can be arranged extremely densely, and the fineness of the display section 281 can be made extremely high. For example, in the display section 281, the pixels 284a are preferably arranged with a fineness of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, still more preferably 6000 ppi or more, and 20000 ppi or less, or 30000 ppi or less.

[0231] Since such a display module 280 is extremely high-definition, it can be suitably used for VR devices such as head-mounted displays or glasses-type AR devices. For example, even in the case of a configuration in which the display section of the display module 280 is viewed through a lens, since the display module 280 has an extremely high-definition display section 281, pixels cannot be viewed even when the display section is enlarged by the lens, and a highly immersive display can be performed. Also, the display module 280 is not limited to this, and can be suitably used for electronic devices having a relatively small display section. For example, it can be suitably used for the display section of wearable electronic devices such as wristwatches.

[0232] This embodiment can be implemented in appropriate combination with at least a part of other embodiments described in this specification.

[0233] (Embodiment 2) In this embodiment, a display device according to one aspect of the present invention will be described with reference to FIG. 14.

[0234] The display device shown in FIG. 14A includes a pixel section 502, a driving circuit section 504, a protection circuit 506, and a terminal section 507. Note that the display device according to one aspect of the present invention may be configured without the protection circuit 506.

[0235] The pixel section 502 includes a plurality of pixel circuits 501 arranged in X rows and Y columns (X and Y are each independently a natural number of 2 or more). Each pixel circuit 501 has a circuit for driving a display element.

[0236] The driving circuit section 504 includes driving circuits such as a gate driver 504a that outputs a scanning signal to gate lines GL_1 to GL_X and a source driver 504b that supplies a data signal to data lines DL_1 to DL_Y. The gate driver 504a may be configured to have at least a shift register. The source driver 504b is configured using, for example, a plurality of analog switches. Alternatively, the source driver 504b may be configured using a shift register or the like.

[0237] The terminal section 507 refers to a portion where terminals for inputting power, a control signal, an image signal, etc. from an external circuit to the display device are provided.

[0238] The protection circuit 506 is a circuit that makes a wiring to which it is connected and another wiring in a conductive state when a potential outside a certain range is applied to the wiring to which it is connected. The protection circuit 506 shown in FIG. 14A is connected to various wirings such as a gate line GL which is a wiring between the gate driver 504a and the pixel circuit 501, or a data line DL which is a wiring between the source driver 504b and the pixel circuit 501. In FIG. 14A, hatching is applied to the protection circuit 506 to distinguish it from the pixel circuit 501.

[0239] Further, the gate driver 504a and the source driver 504b may be provided on the same substrate as the pixel portion 502, or a substrate on which a gate driver circuit or a source driver circuit is separately formed (for example, a driving circuit substrate formed of a single crystal semiconductor or a polycrystalline semiconductor) may be mounted on the substrate by COG or TAB (Tape Automated Bonding).

[0240] In particular, it is preferable to arrange the gate driver 504a and the source driver 504b below the pixel portion 502.

[0241] Further, FIG. 14B shows an example of the configuration of a pixel circuit applicable to the pixel circuit 501.

[0242] The pixel circuit 501 shown in FIG. 14B includes transistors 552 and 554, a capacitive element 562, and a light-emitting element 572. Data lines DL_n, gate lines GL_m, potential supply lines VL_a, and potential supply lines VL_b, etc. are connected to the pixel circuit 501.

[0243] Note that a high power supply potential VDD is applied to one of the potential supply lines VL_a and the potential supply line VL_b, and a low power supply potential VSS is applied to the other. The current flowing through the light-emitting element 572 is controlled according to the potential applied to the gate of the transistor 554, whereby the emission luminance from the light-emitting element 572 is controlled.

[0244] This embodiment can be implemented in appropriate combination with at least a part of other embodiments described in this specification.

[0245] (Embodiment 3) Hereinafter, a pixel circuit including a memory for correcting gradations displayed on a pixel applicable to a display device according to an aspect of the present invention and a display device having the same will be described.

[0246] [Circuit Configuration] FIG. 15A shows a circuit diagram of a pixel circuit 400. The pixel circuit 400 includes a transistor M1, a transistor M2, a capacitor C1, and a circuit 401. Further, wiring S1, wiring S2, wiring G1, and wiring G2 are connected to the pixel circuit 400.

[0247] For the transistor M1, one of the gate is connected to the wiring G1, one of the source and the drain is connected to the wiring S1, and the other is connected to one electrode of the capacitor C1. For the transistor M2, one of the gate is connected to the wiring G2, one of the source and the drain is connected to the wiring S2, and the other is connected to the other electrode of the capacitor C1 and the circuit 401.

[0248] The circuit 401 is a circuit including at least one display element. Various elements can be used as the display element, but typically a light-emitting element such as an organic EL element or an LED element can be used. In addition to this, a liquid crystal element, an MEMS (Micro Electro Mechanical Systems) element, etc. can also be used.

[0249] Let the node connecting the transistor M1 and the capacitor C1 be node N1, and the node connecting the transistor M2 and the circuit 401 be node N2.

[0250] The pixel circuit 400 can hold the potential of node N1 by turning off the transistor M1. Also, the potential of node N2 can be held by turning off the transistor M2. Further, with the transistor M2 turned off, by writing a predetermined potential to node N1 through the transistor M1, the potential of node N2 can be changed according to the displacement of the potential of node N1 by capacitive coupling through the capacitor C1.

[0251] Here, one or both of the transistors M1 and M2 may be a transistor to which an oxide semiconductor exemplified in Embodiment 1 is applied. Therefore, due to an extremely low off-current, the potentials of the nodes N1 and N2 can be held for a long period. Note that when the period for holding the potential of each node is short (specifically, when the frame frequency is 30 Hz or more), a transistor using a semiconductor such as silicon may be used.

[0252] [Example of driving method] Next, an example of the operation method of the pixel circuit 400 will be described with reference to FIG. 15B. FIG. 15B is a timing chart related to the operation of the pixel circuit 400. Here, for ease of explanation, effects such as various resistances such as wiring resistance, parasitic capacitances of transistors or wirings, and threshold voltages of transistors are not considered.

[0253] In the operation shown in FIG. 15B, one frame period is divided into a period T1 and a period T2. The period T1 is a period for writing a potential to the node N2, and the period T2 is a period for writing a potential to the node N1.

[0254] [Period T1] In the period T1, potentials for turning on the transistors are applied to both the wiring G1 and the wiring G2. Also, a potential V ref which is a fixed potential is supplied to the wiring S1, and a first data potential V w is supplied to the wiring S2.

[0255] The potential V ref is applied to the node N1 from the wiring S1 through the transistor M1. Also, the first data potential V w is applied to the node N2 from the wiring S2 through the transistor M2. Therefore, a potential difference V w -V ref is held in the capacitor C1.

[0256] [Period T2] Subsequently, in period T2, a potential that turns on transistor M1 is applied to wiring G1, and a potential that turns off transistor M2 is applied to wiring G2. Also, a second data potential V data is supplied to wiring S1. A predetermined constant potential may be applied to wiring S2, or it may be in a floating state.

[0257] At node N1, the second data potential V data is applied from wiring S1 through transistor M1. At this time, due to capacitive coupling by capacitor C1, the potential of node N2 changes by potential dV according to the second data potential V data . That is, a potential obtained by adding the first data potential V w and potential dV is input to circuit 401. Note that in FIG. 15B, potential dV is shown as a positive value, but it may be a negative value. That is, the second data potential V data may be lower than potential V ref .

[0258] Here, potential dV is generally determined by the capacitance value of capacitor C1 and the capacitance value of circuit 401. When the capacitance value of capacitor C1 is sufficiently larger than the capacitance value of circuit 401, potential dV becomes a potential close to the second data potential V data .

[0259] In this way, pixel circuit 400 can generate a potential to be supplied to circuit 401 including a display element by combining two types of data signals, so that gradation correction can be performed within pixel circuit 400.

[0260] Also, pixel circuit 400 can generate a potential exceeding the maximum potential that can be supplied to wiring S1 and wiring S2. For example, when a light-emitting element is used, high dynamic range (HDR) display or the like can be performed. Also, when a liquid crystal element is used, overdrive driving or the like can be realized.

[0261] [Application Example] The pixel circuit 400EL shown in FIG. 15C has a circuit 401EL. The circuit 401EL has a light-emitting element EL, a transistor M3, and a capacitor C2.

[0262] One electrode of the gate of the transistor M3 is connected to one electrode of the node N2 and the capacitor C2, one of the source and the drain is connected to a wiring that gives a potential VH, and the other is connected to one electrode of the light-emitting element EL, respectively. One electrode of the capacitor C2 is connected to a wiring that gives a potential V com The other electrode of the light-emitting element EL is connected to a wiring that gives a potential V L and is connected to a wiring that gives a potential V

[0263] The transistor M3 has a function of controlling the current supplied to the light-emitting element EL. The capacitor C2 functions as a holding capacitor. The capacitor C2 can be omitted if it is not necessary.

[0264] Here, a configuration in which the anode side of the light-emitting element EL is connected to the transistor M3 is shown, but the transistor M3 may be connected to the cathode side. At this time, the values of the potential V H and the potential V L can be appropriately changed.

[0265] By applying a high potential to the gate of the transistor M3, a large current can flow through the light-emitting element EL, so that, for example, HDR display or the like can be realized. Further, by supplying a correction signal to the wiring S1 or the wiring S2, it is also possible to correct variations in the electrical characteristics of the transistor M3 or the light-emitting element EL.

[0266] Note that the present invention is not limited to the circuit illustrated in FIG. 15C, and a configuration in which a transistor, a capacitor, or the like is separately added may be used.

[0267] This embodiment can be implemented in appropriate combination with at least a part of other embodiments described in this specification.

[0268] (Embodiment 4) In this embodiment, a configuration example of an electronic device to which a display device according to an aspect of the present invention is applied will be described.

[0269] The display device and the display module according to an aspect of the present invention can be applied to a display unit of an electronic device having a display function, such as a television device, a notebook personal computer, a monitor device, a digital signage, a pachinko machine, a game machine, and other electronic devices having a relatively large screen. In addition, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, portable information terminals, audio playback devices, and the like can be mentioned.

[0270] In particular, since the display device and the display module according to an aspect of the present invention can enhance the definition, they can be suitably used for electronic devices having a relatively small display unit. Examples of such electronic devices include wristwatch-type and bracelet-type information terminal devices (wearable devices), VR devices such as head-mounted displays, or AR devices such as glasses-type devices, and other wearable devices that can be worn on the head.

[0271] FIG. 16A shows a perspective view of a glasses-type electronic device 700. The electronic device 700 includes a pair of display panels 701, a pair of housings 702, a pair of optical members 703, a pair of mounting portions 704, and the like.

[0272] The electronic device 700 can project the image displayed on the display panel 701 onto the display area 706 of the optical member 703. In addition, since the optical member 703 has translucency, the user can view the image displayed in the display area 706 overlaid on the transmitted image viewed through the optical member 703. Therefore, the electronic device 700 is an electronic device capable of AR display.

[0273] Also, one housing 702 is provided with a camera 705 capable of imaging the front. Although not shown, one of the housings 702 is provided with a wireless receiver or a connector to which a cable can be connected, and a video signal or the like can be supplied to the housing 702. Further, by providing an acceleration sensor such as a gyro sensor in the housing 702, the orientation of the user's head can be detected, and an image corresponding to the orientation can be displayed on the display area 706. Also, it is preferable that the housing 702 is provided with a battery, and in that case, it can be charged wirelessly or by wire.

[0274] Subsequently, with reference to FIG. 16B, a method of projecting an image onto the display area 706 of the electronic device 700 will be described. Inside the housing 702, a display panel 701, a lens 711, and a reflector 712 are provided. Also, a portion of the optical member 703 corresponding to the display area 706 has a reflecting surface 713 that functions as a half mirror.

[0275] The light 715 emitted from the display panel 701 passes through the lens 711 and is reflected by the reflector 712 toward the optical member 703 side. Inside the optical member 703, the light 715 repeatedly undergoes total reflection at the end face of the optical member 703 and reaches the reflecting surface 713, where an image is projected onto the reflecting surface 713. As a result, the user can visually recognize both the light 715 reflected by the reflecting surface 713 and the transmitted light 716 that has passed through the optical member 703 (including the reflecting surface 713).

[0276] FIG. 16 shows an example in which the reflector 712 and the reflecting surface 713 each have a curved surface. Thereby, the degree of freedom in optical design can be increased and the optical member 703 can be made thinner compared to the case where they are flat. Note that the reflector 712 and the reflecting surface 713 may be flat.

[0277] As the reflector 712, a member having a mirror surface can be used, and it is preferable that the reflectance is high. Also, as the reflecting surface 713, a half mirror using the reflection of a metal film may be used, but if a prism or the like using total reflection is used, the transmittance of the transmitted light 716 can be increased.

[0278] Here, the housing 702 preferably has a mechanism for adjusting the distance between the lens 711 and the display panel 701, or their angles. This enables pin adjustment, image enlargement, reduction, etc. For example, one or both of the lens 711 or the display panel 701 may be configured to be movable in the optical axis direction.

[0279] Also, the housing 702 preferably has a mechanism for adjusting the angle of the reflector 712. By changing the angle of the reflector 712, it becomes possible to change the position of the display area 706 where the image is displayed. This enables the display area 706 to be arranged at an optimal position according to the position of the user's eyes.

[0280] The display device or display module according to one aspect of the present invention can be applied to the display panel 701. Therefore, an electronic device 700 capable of extremely high-precision display can be obtained.

[0281] FIGS. 17A and 17B show perspective views of the goggle-type electronic device 750. FIG. 17A is a perspective view showing the front, plane, and left side of the electronic device 750, and FIG. 17B is a perspective view showing the back, bottom, and right side of the electronic device 750.

[0282] The electronic device 750 includes a pair of display panels 751, a housing 752, a pair of mounting portions 754, a buffer member 755, a pair of lenses 756, etc. The pair of display panels 751 are respectively provided at positions inside the housing 752 where they can be visually recognized through the lenses 756.

[0283] The electronic device 750 is an electronic device for VR. A user wearing the electronic device 750 can visually recognize the image displayed on the display panel 751 through the lens 756. Also, by displaying different images on the pair of display panels 751, three-dimensional display using parallax can be performed.

[0284] On the back side of the housing 752, an input terminal 757 and an output terminal 758 are provided. A cable for supplying a video signal from a video output device or the like, or power for charging a battery provided in the housing 752 can be connected to the input terminal 757. As the output terminal 758, for example, it functions as an audio output terminal and can connect earphones, headphones, etc. Note that when configured to output audio data by wireless communication or when outputting audio from an external video output device, the audio output terminal may not be provided.

[0285] Further, the housing 752 preferably has a mechanism capable of adjusting the left and right positions of the lens 756 and the display panel 751 so that they are in optimal positions according to the position of the user's eyes. Also, it preferably has a mechanism for adjusting focus by changing the distance between the lens 756 and the display panel 751.

[0286] The display device or display module according to one aspect of the present invention can be applied to the display panel 751. Therefore, the electronic device 750 can be made to have extremely high resolution display. Thereby, a high sense of immersion can be given to the user.

[0287] The buffer member 755 is a part that comes into contact with the user's face (forehead, cheeks, etc.). When the buffer member 755 is in close contact with the user's face, light leakage can be prevented and the sense of immersion can be enhanced. It is preferable to use a soft material as the buffer member 755 so that it adheres to the user's face when the user wears the electronic device 750. For example, materials such as rubber, silicone rubber, urethane, and sponge can be used. Also, using a sponge or the like with its surface covered with cloth, leather (natural leather or synthetic leather), etc. can prevent light leakage preferably as it is difficult for a gap to occur between the user's face and the buffer member 755. Further, using such a material is preferable because in addition to a good texture, it does not make the user feel cold when worn in cold seasons. It is preferable that members such as the buffer member 755 or the mounting portion 754 that come into contact with the user's skin are detachable, as this facilitates cleaning or replacement.

[0288] This embodiment can be implemented in appropriate combination with at least some of the other embodiments described in this specification.

Description of Reference Numerals

[0289] 100A~G, 200, 200A~D: Indicating devices, 101, 201, 202: Substrates, 111, 114, 114B, 114G, 114R, 116, 141, 142, 143, 211, 224, 225, 227, 241, 242, 251, 252, 253, 271a, 271b: Conductive layers, 111f, 112f, 130f, 141f, 142f, 143f: Conductive films, 112: Reflective layer, 113, 117, 118, 121: Insulating layers, 113f: Insulating film, 115: EL layer, 120, 120R, 120B, 120G: Light-emitting elements, 130, 131, 271~274: Plugs, 151, 152, 153, 154, 155, 156: Resist masks, 161~163, 213, 21, 223, 226, 228, 229, 231, 232, 243, 261, 261a, 261b, 262~265: Insulating layers, 164: Adhesive layer, 165B, 165G, 165R: Coloring layers, 210, 220, 230: Transistors, 212: Low-resistance region, 215: Element isolation layer, 221: Semiconductor layer, 240: Capacitive element, 280: Display module, 281: Display unit, 282: Circuit unit, 283: Pixel circuit unit, 283a: Pixel circuit, 284: Pixel portion, 84a: Pixel, 285: Terminal portion, 286: Wiring portion, 290: FPC

Claims

1. having a first light-emitting element and a second light-emitting element, wherein the first light-emitting element has a first lower electrode, a first reflective layer, a first insulating layer, a first conductive layer, a light-emitting layer, and an upper electrode, the first lower electrode, the first reflective layer, the first insulating layer, the first conductive layer, the light-emitting layer, and the upper electrode are stacked in this order, the second light-emitting element has a second lower electrode, a second reflective layer, a second insulating layer, a second conductive layer, the light-emitting layer, and the upper electrode, the second lower electrode, the second reflective layer, the second insulating layer, the second conductive layer, the light-emitting layer, and the upper electrode are stacked in this order, the first conductive layer, the first insulating layer, the second conductive layer, and the second insulating layer are light-transmissive, the second conductive layer is thicker than the first conductive layer, the upper electrode is transmissive and reflective to visible light, the first lower electrode is electrically connected to the first conductive layer, the second lower electrode is electrically connected to the second conductive layer, a display device.

2. In Claim 1, the first lower electrode is covered by the first conductive layer, the second lower electrode is covered by the second conductive layer, a display device.

3. having a first light-emitting element, a second light-emitting element, a first plug, and a second plug, wherein the first light-emitting element has a first lower electrode, a first reflective layer, a first insulating layer, a first conductive layer, a light-emitting layer, and an upper electrode, the first lower electrode, the first reflective layer, the first insulating layer, the first conductive layer, the light-emitting layer, and the upper electrode are stacked in this order, the second light-emitting element has a second lower electrode, a second reflective layer, a second insulating layer, a second conductive layer, the light-emitting layer, and the upper electrode, the second lower electrode, the second reflective layer, the second insulating layer, the second conductive layer, the light-emitting layer, and the upper electrode are stacked in this order, the first conductive layer, the first insulating layer, the second conductive layer, and the second insulating layer are light-transmissive, the second conductive layer is thicker than the first conductive layer, the upper electrode is transmissive and reflective to visible light, the first lower electrode is electrically connected to the first conductive layer via the first plug, the second lower electrode is electrically connected to the second conductive layer via the second plug, the first plug is embedded in the first insulating layer, The second plug is embedded in the second insulating layer, a display device.

4. In any one of Claims 1 to 3, the first conductive layer has a first film, the second conductive layer has a second film and a third film, the second film and the third film are laminated in this order, the first film and the third film are films having the same composition, a display device.

5. In any one of Claims 1 to 4, having a circuit layer including a transistor, the first light-emitting element is provided on the circuit layer and electrically connected to the transistor, a display device.

6. In Claim 5, the transistor includes a metal oxide having crystallinity or single crystal silicon in a semiconductor layer in which a channel is formed, a display device.

7. In any one of Claims 1 to 4, a first circuit layer including a first transistor, a second circuit layer including a second transistor, a third insulating layer located on the first circuit layer, and a fourth insulating layer between the first circuit layer and the second circuit layer, the first light-emitting element is electrically connected to the first transistor, a display device.

8. In Claim 7, the first transistor includes a metal oxide having crystallinity in a first semiconductor layer in which a channel is formed, the second transistor includes a metal oxide having crystallinity or single crystal silicon in a second semiconductor layer in which a channel is formed, a display device.

9. In any one of Claims 1 to 8, having a plurality of the first light-emitting elements, the first light-emitting elements are periodically arranged with a fineness of 2000 ppi or more, a display device.

10. In Claim 9, the first light-emitting elements are arranged in a delta array, a display device.

11. A step of forming a first lower electrode and a second lower electrode separately on a surface to be formed; a step of forming a first reflective layer on the first lower electrode and a second reflective layer on the second lower electrode; a step of forming a first insulating layer on the first reflective layer and a second insulating layer on the second reflective layer; a step of forming a first conductive layer covering the first lower electrode and a second conductive layer covering the second lower electrode; a step of forming a light-emitting layer on the first conductive layer and the second conductive layer, and an upper electrode on the light-emitting layer. The second conductive layer is formed thicker than the first conductive layer. The first conductive layer and the second conductive layer are formed to have translucency. The first lower electrode is electrically connected to the first conductive layer. The second lower electrode is electrically connected to the second conductive layer. The upper electrode is formed to have translucency and reflectivity. A method for manufacturing a display device.

12. A step of forming a first conductive film to be a first lower electrode and a second lower electrode on a surface to be formed. A step of forming a second conductive film to be a first reflective layer and a second reflective layer by covering the first conductive film. A step of forming a first insulating film to be a first insulating layer and a second insulating layer on the first conductive film. A step of embedding a first plug and a second plug in the first insulating film and electrically connecting the first plug and the second plug to the first conductive film, respectively. A step of forming a first conductive layer on the first plug. A step of forming a second conductive layer on the second plug. A step of processing the first conductive film, the second conductive film, the first insulating film, the first conductive layer, and the second conductive layer into an island shape to form the first lower electrode, the second lower electrode, the first reflective layer, the second reflective layer, the first insulating layer, and the second insulating layer. A step of forming a light-emitting layer on the first conductive layer and the second conductive layer and an upper electrode on the light-emitting layer. The second conductive layer is formed thicker than the first conductive layer. The first conductive layer and the second conductive layer are formed to have translucency. The first conductive layer is electrically connected to the first lower electrode via the first plug. The second conductive layer is electrically connected to the second lower electrode via the second plug. The upper electrode is formed to have translucency and reflectivity. A method for manufacturing a display device.

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