Display device manufacturing method, display device, display module, and electronic device

Abstract

Provided is a high-definition or high-resolution display apparatus. This display apparatus comprises a first light-emitting device and a second light-emitting device. The first light-emitting device comprises a first pixel electrode, a first hole injection layer, a first hole transport layer, a first light-emitting layer, a first electron transport layer, a second electron transport layer, and a common electrode that are stacked in this order. The second light-emitting device comprises a second pixel electrode, a second hole injection layer, a second hole transport layer, a second light-emitting layer, a third electron transport layer, the second electron transport layer, and the common electrode that are stacked in this order. The first light-emitting device and the second light-emitting device have functions of emitting light of different colors from each other. The second electron transport layer covers at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, a side surface of the first light-emitting layer, and a side surface of the second light-emitting layer.

Description

[Technical field]

[0001] 1. Field of the Invention One embodiment of the present invention relates to a display device, a display module, and an electronic device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device (e.g., a touch sensor), an input / output device (e.g., a touch panel), a driving method thereof, or a manufacturing method thereof. [Background technology]

[0003] In recent years, display devices are expected to be used in various applications. For example, applications of large display devices include home television devices (also called televisions or television receivers), digital signage, and public information displays (PIDs). In addition, development of smartphones and tablet terminals equipped with touch panels as mobile information terminals is underway.

[0004] There is also a demand for higher definition display devices. Devices requiring high definition display devices, such as devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR), are being actively developed.

[0005] As a display device, for example, a light-emitting device having a light-emitting device (also called a light-emitting element) has been developed. A light-emitting device (also called an EL device or an EL element) utilizing the electroluminescence (hereinafter referred to as EL) phenomenon has features such as being easily thin and lightweight, being capable of high-speed response to an input signal, and being capable of being driven by a DC constant voltage power supply, and is applied to a display device.

[0006] Patent Document 1 discloses a display device for VR that uses an organic EL device (also called an organic EL element). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2018 / 087625 Summary of the Invention [Problem to be solved by the invention]

[0008] When producing a display device having a plurality of organic EL devices each having a different emission color from its emission layer, it is necessary to form each of the emission layers having different emission colors in an island shape.

[0009] For example, an island-shaped light-emitting layer can be formed by a vacuum deposition method using a metal mask (also called a shadow mask). However, during deposition, the contours of the layer may become blurred and the thickness of the edge may become thin. In other words, the island-shaped light-emitting layer may have a variation in thickness depending on the location. In addition, when manufacturing a large-sized, high-resolution, or high-definition display device, there is a concern that the manufacturing yield will be low due to low dimensional accuracy of the metal mask and deformation due to heat, etc.

[0010] Furthermore, when manufacturing a display device using a vacuum deposition method that uses a metal mask, there is an issue that multiple lines of manufacturing equipment are required. For example, since it is necessary to periodically clean the metal mask, at least two or more lines of manufacturing equipment must be prepared, and one manufacturing equipment must be used for manufacturing while the other manufacturing equipment is under maintenance, and multiple lines of manufacturing equipment are required when considering mass production. Therefore, there is an issue that the initial investment for introducing the manufacturing equipment is very large.

[0011] An object of one embodiment of the present invention is to provide a method for manufacturing a high-resolution display device.An object of one embodiment of the present invention is to provide a method for manufacturing a high-resolution display device.An object of one embodiment of the present invention is to provide a method for manufacturing a large-sized display device.An object of one embodiment of the present invention is to provide a method for manufacturing a highly reliable display device.An object of one embodiment of the present invention is to provide a method for manufacturing a display device with high yield.

[0012] An object of one embodiment of the present invention is to provide a high-definition display device.An object of one embodiment of the present invention is to provide a high-resolution display device.An object of one embodiment of the present invention is to provide a large-sized display device.An object of one embodiment of the present invention is to provide a highly reliable display device.

[0013] Note that the description of these problems does not preclude the existence of other problems. One embodiment of the present invention does not necessarily have to solve all of these problems. Problems other than these can be extracted from the description of the specification, drawings, and claims. [Means for solving the problem]

[0014] One embodiment of the present invention is a display device having a first light-emitting device and a second light-emitting device. The first light-emitting device has a first pixel electrode, a first hole injection layer on the first pixel electrode, a first hole transport layer on the first hole injection layer, a first light-emitting layer on the first hole transport layer, a first electron transport layer on the first light-emitting layer, a second electron transport layer on the first electron transport layer, an electron injection layer on the second electron transport layer, and a common electrode on the electron injection layer. The second light-emitting device has a second pixel electrode, a second hole injection layer on the second pixel electrode, a second hole transport layer on the second hole injection layer, a second light-emitting layer on the second hole transport layer, a third electron transport layer on the second light-emitting layer, a second electron transport layer on the third electron transport layer, an electron injection layer on the second electron transport layer, and a common electrode on the electron injection layer. The first light emitting device and the second light emitting device have a function of emitting light of different colors. The second electron transport layer covers at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, a side surface of the first light emitting layer, and a side surface of the second light emitting layer.

[0015] The display device preferably has a protective layer on the common electrode.

[0016] The first light emitting device and the second light emitting device are preferably provided on an insulating layer, which may have a recess, and the second electron transport layer may contact the recess.

[0017] There may be a gap between the second electron transport layer and the electron injection layer, or an insulator may be provided between the second electron transport layer and the electron injection layer.

[0018] One embodiment of the present invention is a display module having a display device of any of the above configurations, and having a connector such as a flexible printed circuit (hereinafter referred to as FPC) or a TCP (Tape Carrier Package) attached, or a display module having an integrated circuit (IC) mounted by a COG (Chip On Glass) method or a COF (Chip On Film) method, etc.

[0019] One embodiment of the present invention is an electronic device including the above-described display module and at least one of a housing, a battery, a camera, a speaker, and a microphone.

[0020] One embodiment of the present invention includes forming an insulating layer, forming a conductive film on the insulating layer, forming a first hole injection layer on the conductive film, forming a first hole transport layer on the first hole injection layer, forming a first light-emitting layer on the first hole transport layer, forming a first electron transport layer on the first light-emitting layer, forming a first sacrificial layer on the first electron transport layer, processing the first hole injection layer, the first hole transport layer, the first light-emitting layer, the first electron transport layer, and the first sacrificial layer to expose a part of the conductive film, forming a second hole injection layer on the first sacrificial layer and on the conductive film, forming a second hole transport layer on the second hole injection layer, forming a second light-emitting layer on the second hole transport layer, and forming a second light-emitting layer on the second light-emitting layer. a second electron-transport layer, a second sacrificial layer on the second electron-transport layer, a second hole-injection layer, a second hole-transport layer, a second light-emitting layer, a second electron-transport layer, and a second sacrificial layer are processed to expose a part of a conductive film, a first pixel electrode overlapping with the first sacrificial layer and a second pixel electrode overlapping with the second sacrificial layer are formed by processing the conductive film using the first sacrificial layer and the second sacrificial layer as a hard mask, the first sacrificial layer and the second sacrificial layer are removed, a third electron-transport layer is formed on the first electron-transport layer and the second electron-transport layer, an electron injection layer is formed on the third electron-transport layer, and a common electrode is formed on the electron injection layer.

[0021] Furthermore, it is preferable to form a protective layer on the common electrode.

[0022] In the above-mentioned method for manufacturing a display device, the third electron transport layer is preferably provided so as to cover at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, a side surface of the first light-emitting layer, and a side surface of the second light-emitting layer.

[0023] In the above-described method for manufacturing a display device, before the electron injection layer is formed, the recesses in the third electron transport layer may be filled with an insulating material.

[0024] In the process of processing the conductive film, a recess may be formed in the insulating layer. Effect of the Invention

[0025] According to one embodiment of the present invention, a method for manufacturing a high-definition display device can be provided. According to one embodiment of the present invention, a method for manufacturing a high-resolution display device can be provided. According to one embodiment of the present invention, a method for manufacturing a large-sized display device can be provided. According to one embodiment of the present invention, a method for manufacturing a highly reliable display device can be provided. According to one embodiment of the present invention, a method for manufacturing a display device with high yield can be provided.

[0026] According to one embodiment of the present invention, a high-definition display device can be provided. According to one embodiment of the present invention, a high-resolution display device can be provided. According to one embodiment of the present invention, a large-sized display device can be provided. According to one embodiment of the present invention, a highly reliable display device can be provided.

[0027] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims. [Brief description of the drawings]

[0028] Fig. 1A is a top view showing an example of a display device, and Fig. 1B is a cross-sectional view showing the example of the display device. 2A to 2C are top views showing an example of a display device. 3A to 3C are cross-sectional views showing an example of a method for manufacturing a display device. 4A to 4C are cross-sectional views showing an example of a method for manufacturing a display device. 5A to 5C are cross-sectional views showing an example of a method for manufacturing a display device. 6A to 6C are cross-sectional views showing an example of a method for manufacturing a display device. 7A to 7C are cross-sectional views showing an example of a method for manufacturing a display device. 8A and 8B are perspective views showing an example of a display module. FIG. 9 is a cross-sectional view showing an example of a display device. FIG. 10 is a cross-sectional view showing an example of a display device. FIG. 11 is a cross-sectional view showing an example of a display device. 12A to 12D are diagrams showing configuration examples of a light-emitting device. 13A and 13B are diagrams illustrating an example of an electronic device. 14A and 14B are diagrams illustrating an example of an electronic device. 15A and 15B are diagrams illustrating an example of an electronic device. 16A to 16D are diagrams showing an example of an electronic device. 17A to 17F are diagrams showing an example of an electronic device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that the modes and details of the present invention can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0030] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and the repeated explanations are omitted. In addition, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be used.

[0031] In addition, for ease of understanding, the position, size, range, etc. of each component shown in the drawings may not represent the actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings.

[0032] In this specification, the ordinal numbers "first" and "second" are used for convenience and do not limit the number of components or the order of the components (e.g., the order of processes or the order of stacking). In addition, an ordinal number attached to a component in a certain part of this specification may not match an ordinal number attached to the same component in another part of this specification or in the claims. In addition, the words "film" and "layer" can be interchanged depending on the situation. For example, the term "conductive layer" can be changed to the term "conductive film". Or, for example, the term "insulating film" can be changed to the term "insulating layer".

[0033] In this specification, a device fabricated using a metal mask or an FMM (fine metal mask, high-definition metal mask) may be referred to as a device with an MM (metal mask) structure. Also, in this specification, a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure.

[0034] (Embodiment 1) In this embodiment, a display device of one embodiment of the present invention and a manufacturing method thereof will be described with reference to FIGS.

[0035] In a manufacturing method of a display device according to one embodiment of the present invention, a conductive film is formed, and a first layer (which can be called an EL layer or a part of an EL layer) including a light-emitting layer that emits light of a first color is formed on one surface, and then a first sacrificial layer is formed on the first layer. Then, a first resist mask is formed on the first sacrificial layer, and the first layer and the first sacrificial layer are processed using the first resist mask to form an island-shaped first layer. Then, a second layer (which can be called an EL layer or a part of an EL layer) including a light-emitting layer that emits light of a second color is formed in an island shape using a second sacrificial layer and a second resist mask, similar to the first layer.

[0036] In this manner, in the manufacturing method of the display device according to one embodiment of the present invention, the island-shaped EL layer is formed by forming the EL layer on one surface and then processing it, and therefore the island-shaped EL layer can be formed with a uniform thickness. In addition, by providing a sacrificial layer on the EL layer, damage to the EL layer during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0037] After forming the EL layers that emit light of each color, the sacrificial layer remaining on each EL layer is used as a hard mask to process the conductive film to form pixel electrodes. Since there is no need to provide a separate mask for forming the pixel electrodes in an island shape, the manufacturing cost of the display device can be reduced. In addition, since there is no need to provide an insulating layer between the pixel electrodes and the EL layers to cover the ends of the pixel electrodes, the distance between adjacent light-emitting devices can be made extremely narrow. Therefore, the display device can be made highly precise or highly high-resolution.

[0038] Here, the first layer and the second layer each include at least a light-emitting layer, and preferably consist of a plurality of layers. Specifically, it is preferable to have one or more layers on the light-emitting layer. By having another layer between the light-emitting layer and the sacrificial layer, it is possible to suppress exposure of the light-emitting layer to the outermost surface during the manufacturing process of the display device, and to reduce damage to the light-emitting layer. This can increase the reliability of the light-emitting device. Therefore, it is preferable that the first layer and the second layer each have a light-emitting layer and a carrier transport layer on the light-emitting layer.

[0039] In the light-emitting devices that emit light of different colors, it is not necessary to separately prepare all layers constituting the EL layer, and some layers can be formed in the same process. In the manufacturing method of the display device according to one embodiment of the present invention, after some layers constituting the EL layer are formed in an island shape for each color, the sacrificial layer is removed, and the remaining layers constituting the EL layer and a common electrode (also called an upper electrode) are formed in common to the light-emitting devices of each color. For example, the carrier injection layer and the common electrode can be formed in common to the light-emitting devices of each color. On the other hand, the carrier injection layer is often a layer with relatively high conductivity among the EL layers. Therefore, the light-emitting device may be short-circuited when the carrier injection layer contacts the side of some layers of the EL layer formed in an island shape or the side of the pixel electrode. In addition, even when the carrier injection layer is provided in an island shape and the common electrode is formed in common to the light-emitting devices of each color, the light-emitting device may be short-circuited when the common electrode contacts the side of the EL layer or the side of the pixel electrode.

[0040] Therefore, a display device according to one embodiment of the present invention has two layers between an island-shaped light-emitting layer and a carrier injection layer provided in common to the light-emitting devices of each color: an island-shaped first carrier transport layer and a second carrier transport layer provided in common to the light-emitting devices of each color.

[0041] This makes it possible to prevent a part of the EL layer formed in an island shape and the pixel electrode from coming into contact with the carrier injection layer, thereby making it possible to prevent short circuits in the light-emitting device and to improve the reliability of the light-emitting device.

[0042] A display device of one embodiment of the present invention includes a pixel electrode functioning as an anode, a hole injection layer, a hole transport layer, a light-emitting layer, and a first electron transport layer, which are each provided in this order over the pixel electrode, and which have an island shape, a second electron transport layer provided so as to cover the pixel electrode, the hole injection layer, the hole transport layer, the light-emitting layer, and the first electron transport layer, an electron injection layer provided on the second electron transport layer, and a common electrode provided on the electron injection layer and which functions as a cathode.

[0043] Alternatively, a display device of one embodiment of the present invention includes a pixel electrode functioning as a cathode; an electron-injection layer, an electron-transport layer, a light-emitting layer, and a first hole-transport layer, which are each formed in an island shape over the pixel electrode in this order; a second hole-transport layer provided to cover the pixel electrode, the electron-injection layer, the electron-transport layer, the light-emitting layer, and the first hole-transport layer; a hole-injection layer provided over the second hole-transport layer; and a common electrode provided over the hole-injection layer and functioning as an anode.

[0044] With such a structure, a display device with high definition or resolution and high reliability can be manufactured.

[0045] [Example of display device configuration] 1A and 1B show a display device according to one embodiment of the present invention.

[0046] 1A shows a top view of a display device 100. The display device 100 has a display section in which a plurality of pixels 110 are arranged in a matrix, and a connection section 140 on the outside of the display section. One pixel 110 is composed of three subpixels, 110a, 110b, and 110c. The connection section 140 can also be called a cathode contact section.

[0047] The top shape of the subpixel shown in FIG. 1A corresponds to the top shape of the light-emitting region.

[0048] In addition, the layout of the circuits constituting the subpixels is not limited to the range of the subpixels shown in Fig. 1A and may be arranged outside the range. For example, the transistors of the subpixel 110a may be located within the range of the subpixel 110b shown in Fig. 1A, or a part or all of the transistors may be located outside the range of the subpixel 110a.

[0049] 1A, the aperture ratios (sizes, which can also be said to be sizes of light-emitting regions) of the subpixels 110a, 110b, and 110c are shown to be equal or approximately equal, but one embodiment of the present invention is not limited thereto. The aperture ratios of the subpixels 110a, 110b, and 110c can be determined appropriately. The aperture ratios of the subpixels 110a, 110b, and 110c may be different from each other, or two or more of them may be equal or approximately equal.

[0050] 1A shows an example in which subpixels of different colors are arranged side by side in the X direction, and subpixels of the same color are arranged side by side in the Y direction. Note that subpixels of different colors may be arranged side by side in the Y direction, and subpixels of the same color may be arranged side by side in the X direction.

[0051] 1A shows an example in which the connection unit 140 is located below the display unit in top view, but is not particularly limited thereto. The connection unit 140 may be provided in at least one of the upper, right, left, and lower sides of the display unit in top view, and may be provided so as to surround the four sides of the display unit.

[0052] FIG. 1B shows a cross-sectional view taken along dashed line X1-X2 in FIG. 1A.

[0053] 1B, in the display device 100, light-emitting devices 130a, 130b, and 130c are provided on a layer 101 including transistors, and protective layers 131 and 132 are provided to cover these light-emitting devices. A substrate 120 is attached to the protective layer 132 by a resin layer 119.

[0054] The display device of one embodiment of the present invention may be any of a top emission type that emits light in a direction opposite to the substrate on which the light-emitting device is formed, a bottom emission type that emits light toward the substrate on which the light-emitting device is formed, and a dual emission type that emits light to both sides.

[0055] The transistor-containing layer 101 may have a laminated structure in which a plurality of transistors are provided on a substrate and an insulating layer is provided to cover the transistors. The transistor-containing layer 101 may have a recess between adjacent light-emitting devices. For example, a recess may be provided in an insulating layer located on the outermost surface of the transistor-containing layer 101. A configuration example of the transistor-containing layer 101 will be described later in embodiment 2.

[0056] The light emitting devices 130a, 130b, and 130c each emit light of a different color, and preferably emit light of three colors, for example, red (R), green (G), and blue (B).

[0057] A light-emitting device has an EL layer between a pair of electrodes. In this specification and the like, one of the pair of electrodes may be referred to as a pixel electrode and the other as a common electrode.

[0058] Of a pair of electrodes included in a light-emitting device, one electrode functions as an anode and the other electrode functions as a cathode. In the following, a case where a pixel electrode functions as an anode and a common electrode functions as a cathode will be described as an example.

[0059] The light-emitting device 130a has a pixel electrode 111a on the transistor-containing layer 101, an island-shaped first layer 113a on the pixel electrode 111a, a fourth electron transport layer 116 covering the top and side surfaces of the island-shaped first layer 113a, an electron injection layer 114 on the fourth electron transport layer 116, and a common electrode 115 on the electron injection layer 114. The first layer 113a has a first hole injection layer 181a on the pixel electrode 111a, a first hole transport layer 182a on the first hole injection layer 181a, a first light-emitting layer 183a on the first hole transport layer 182a, and a first electron transport layer 184a on the first light-emitting layer 183a. In light-emitting device 130a, first layer 113a, fourth electron-transport layer 116, and electron-injection layer 114 can be collectively referred to as the EL layer.

[0060] The light-emitting device 130b has a pixel electrode 111b on the transistor-containing layer 101, an island-shaped second layer 113b on the pixel electrode 111b, a fourth electron transport layer 116 covering the top and side surfaces of the island-shaped second layer 113b, an electron injection layer 114 on the fourth electron transport layer 116, and a common electrode 115 on the electron injection layer 114. The second layer 113b has a second hole injection layer 181b on the pixel electrode 111b, a second hole transport layer 182b on the second hole injection layer 181b, a second light-emitting layer 183b on the second hole transport layer 182b, and a second electron transport layer 184b on the second light-emitting layer 183b. In light-emitting device 130b, second layer 113b, fourth electron-transport layer 116, and electron-injection layer 114 can be collectively referred to as the EL layer.

[0061] The light-emitting device 130c has a pixel electrode 111c on the transistor-containing layer 101, an island-shaped third layer 113c on the pixel electrode 111c, a fourth electron transport layer 116 covering the top and side surfaces of the island-shaped third layer 113c, an electron injection layer 114 on the fourth electron transport layer 116, and a common electrode 115 on the electron injection layer 114. The third layer 113c has a third hole injection layer 181c on the pixel electrode 111c, a third hole transport layer 182c on the third hole injection layer 181c, a third light-emitting layer 183c on the third hole transport layer 182c, and a third electron transport layer 184c on the third light-emitting layer 183c. In light-emitting device 130c, third layer 113c, fourth electron-transport layer 116, and electron-injection layer 114 can be collectively referred to as the EL layer.

[0062] A common electrode shared by the light emitting devices of each color is electrically connected to a conductive layer provided in the connection portion 140 .

[0063] Of the pixel electrode and the common electrode, the electrode from which light is extracted is made of a conductive film that transmits visible light, and the electrode from which light is not extracted is preferably made of a conductive film that reflects visible light.

[0064] The material for forming the pair of electrodes (pixel electrode and common electrode) of the light-emitting device may be a metal, an alloy, an electrically conductive compound, or a mixture thereof, etc. Specific examples include indium tin oxide (In-Sn oxide, also called ITO), In-Si-Sn oxide (also called ITSO), indium zinc oxide (In-Zn oxide), In-W-Zn oxide, an alloy containing aluminum (aluminum alloy) such as an alloy of aluminum, nickel, and lanthanum (Al-Ni-La), and an alloy of silver, palladium, and copper (Ag-Pd-Cu, also called APC). In addition, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys containing these in appropriate combinations can also be used. In addition, elements belonging to Group 1 or Group 2 of the periodic table (e.g., lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), europium (Eu), ytterbium (Yb), and other rare earth metals and alloys containing these in appropriate combinations, graphene, and the like can be used.

[0065] It is preferable that a micro-optical resonator (microcavity) structure is applied to the light-emitting device. Therefore, it is preferable that one of a pair of electrodes of the light-emitting device has an electrode (semi-transmissive / semi-reflective electrode) that is transparent and reflective to visible light, and the other has an electrode (reflective electrode) that is reflective to visible light. When the light-emitting device has a microcavity structure, the light emitted from the light-emitting layer can be resonated between both electrodes, and the light emitted from the light-emitting device can be intensified.

[0066] The semi-transmissive / semi-reflective electrode may have a laminated structure of a reflective electrode and an electrode that is transparent to visible light (also called a transparent electrode).

[0067] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode with a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more for a light emitting device. The visible light reflectance of the semi-transmissive / semi-reflective electrode is 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes is 1×10 -2 Ωcm or less is preferable.

[0068] The first layer 113a, the second layer 113b, and the third layer 113c are each provided in an island shape. The first layer 113a, the second layer 113b, and the third layer 113c each have a light-emitting layer. It is preferable that the first layer 113a, the second layer 113b, and the third layer 113c each have a light-emitting layer that emits light of a different color.

[0069] The light-emitting layer is a layer containing a light-emitting substance. The light-emitting layer can have one or more types of light-emitting substances. As the light-emitting substance, a substance that emits light of a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red is appropriately used. In addition, a substance that emits near-infrared light can also be used as the light-emitting substance.

[0070] Examples of the light-emitting substance include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence (TADF) materials, and quantum dot materials.

[0071] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0072] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton, organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand, platinum complexes, and rare earth metal complexes.

[0073] The light-emitting layer may contain one or more organic compounds (host materials, assist materials, etc.) in addition to the light-emitting substance (guest material). As the one or more organic compounds, one or both of a hole-transporting material and an electron-transporting material may be used. As the one or more organic compounds, a bipolar material or a TADF material may be used.

[0074] The light-emitting layer preferably contains, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material that are a combination that easily forms an exciplex. With this configuration, light emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from an exciplex to a light-emitting material (phosphorescent material), can be efficiently obtained. By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest energy absorption band of the light-emitting material, energy transfer becomes smooth and light emission can be efficiently obtained. With this configuration, high efficiency, low voltage operation, and long life of the light-emitting device can be simultaneously achieved.

[0075] The first layer 113a, the second layer 113b, and the third layer 113c may further include a layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a hole-blocking material, a substance with high electron-transport properties, a substance with high electron-injection properties, an electron-blocking material, a bipolar substance (a substance with high electron-transport properties and high hole-transport properties), or the like, as a layer other than the light-emitting layer.

[0076] The light-emitting device may use either a low molecular weight compound or a high molecular weight compound, and may contain an inorganic compound. The layers constituting the light-emitting device may be formed by a deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, a coating method, or the like.

[0077] For example, the first layer 113a, the second layer 113b, and the third layer 113c may each include one or more of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0078] Among the EL layers, the layer formed in common to the light-emitting devices of each color may be one or more of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0079] In the display device 100 shown in FIG. 1B, the first layer 113a has a first light-emitting layer 183a and a first electron transport layer 184a on the first light-emitting layer 183a. Similarly, the second layer 113b has a second light-emitting layer 183b and a second electron transport layer 184b on the second light-emitting layer 183b, and the third layer 113c has a third light-emitting layer 183c and a third electron transport layer 184c on the third light-emitting layer 183c. This can prevent the light-emitting layer from being exposed to the outermost surface during the manufacturing process of the display device 100, and reduce damage to the light-emitting layer. This can improve the reliability of the light-emitting device.

[0080] The first layer 113a, the second layer 113b, and the third layer 113c are covered with a fourth electron transport layer 116, and the electron injection layer 114 and the common electrode 115 are provided on the fourth electron transport layer 116. This prevents the electron injection layer 114 or the common electrode 115 from contacting any of the side surfaces of the pixel electrodes 111a, 111b, and 111c and the first layer 113a, the second layer 113b, and the third layer 113c, thereby preventing a short circuit in the light-emitting device.

[0081] The hole injection layer is a layer that injects holes from the anode to the hole transport layer and contains a material with high hole injection properties, such as an aromatic amine compound and a composite material containing a hole transport material and an acceptor material (electron accepting material).

[0082] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light emitting layer. The hole transport layer is a layer that contains a hole transport material. The hole transport material is 1×10 -6 cm 2 A material having a hole mobility of 100 / Vs or more is preferable. Note that other materials can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, a material having a high hole transporting property such as a π-electron-rich heteroaromatic compound (e.g., a carbazole derivative, a thiophene derivative, a furan derivative, etc.) or an aromatic amine (a compound having an aromatic amine skeleton) is preferable.

[0083] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light emitting layer. The electron transport layer is a layer that contains an electron transporting material. The electron transporting material is preferably 1×10 -6 cm 2 A material having an electron mobility of 100 / Vs or more is preferable. Note that, other materials may be used as long as they have a higher electron transporting property than holes. As the electron transporting material, a material having a high electron transporting property may be used, such as a metal complex having a quinoline skeleton, a metal complex having a benzoquinoline skeleton, a metal complex having an oxazole skeleton, a metal complex having a thiazole skeleton, an oxadiazole derivative, a triazole derivative, an imidazole derivative, an oxazole derivative, a thiazole derivative, a phenanthroline derivative, a quinoline derivative having a quinoline ligand, a benzoquinoline derivative, a quinoxaline derivative, a dibenzoquinoxaline derivative, a pyridine derivative, a bipyridine derivative, a pyrimidine derivative, and other π-electron deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds.

[0084] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer, and is a layer that contains a material with high electron injection properties. As the material with high electron injection properties, an alkali metal, an alkaline earth metal, or a compound thereof can be used. As the material with high electron injection properties, a composite material containing an electron transport material and a donor material (electron donor material) can also be used.

[0085] Examples of the electron injection layer include lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), and calcium fluoride (CaF 2 ), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatolithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviation: LiPPP), lithium oxide (LiO x ), alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used.

[0086] Alternatively, an electron transporting material may be used as the electron injection layer. For example, a compound having an unshared electron pair and an electron-deficient heteroaromatic ring may be used as the electron transporting material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), and a triazine ring may be used.

[0087] The lowest unoccupied molecular orbital (LUMO) of an organic compound having an unshared electron pair is preferably −3.6 eV or more and −2.3 eV or less. Generally, the highest occupied molecular orbital (HOMO) level and the LUMO level of an organic compound can be estimated by CV (cyclic voltammetry), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, or the like.

[0088] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviation: BPhen), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), etc. can be used as organic compounds having unshared electron pairs. Note that NBPhen has a higher glass transition temperature (Tg) and is more heat resistant than BPhen.

[0089] It is preferable to have protective layers 131 and 132 on the light emitting devices 130a, 130b, and 130c. By providing the protective layers 131 and 132, the reliability of the light emitting devices can be improved.

[0090] There is no restriction on the conductivity of the protective layers 131 and 132. As the protective layers 131 and 132, at least one of an insulating film, a semiconductor film, and a conductive film can be used.

[0091] The protective layers 131 and 132 have inorganic films, which can prevent oxidation of the common electrode 115 and suppress impurities (moisture, oxygen, etc.) from entering the light-emitting devices 130a, 130b, and 130c, thereby suppressing deterioration of the light-emitting devices and improving the reliability of the display device.

[0092] For the protective layers 131 and 132, inorganic insulating films such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film can be used. Examples of the oxide insulating film include a silicon oxide film, an aluminum oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, and a tantalum oxide film. Examples of the nitride insulating film include a silicon nitride film and an aluminum nitride film. Examples of the oxynitride insulating film include a silicon oxynitride film and an aluminum oxynitride film. Examples of the nitride oxide insulating film include a silicon nitride oxide film and an aluminum nitride oxide film.

[0093] In this specification and elsewhere, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0094] Each of the protective layers 131 and 132 preferably includes an insulating nitride film or an insulating nitride oxide film, and more preferably includes an insulating nitride film.

[0095] Alternatively, an inorganic film containing In-Sn oxide (also referred to as ITO), In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, indium gallium zinc oxide (In-Ga-Zn oxide, also referred to as IGZO) or the like can be used for the protective layers 131 and 132. The inorganic film preferably has a high resistance, specifically, a higher resistance than the common electrode 115. The inorganic film may further contain nitrogen.

[0096] When light emitted from the light emitting device is extracted through the protective layers 131 and 132, it is preferable that the protective layers 131 and 132 have high transparency to visible light. For example, ITO, IGZO, and aluminum oxide are preferable because they are inorganic materials each having high transparency to visible light.

[0097] The protective layers 131 and 132 may be, for example, a laminated structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a laminated structure of an aluminum oxide film and an IGZO film on the aluminum oxide film. By using such a laminated structure, it is possible to prevent impurities (water, oxygen, etc.) from entering the EL layer side.

[0098] Furthermore, the protective layers 131 and 132 may include an organic film. For example, the protective layer 132 may include both an organic film and an inorganic film.

[0099] Different film formation methods may be used for the protective layer 131 and the protective layer 132. Specifically, the protective layer 131 may be formed by atomic layer deposition (ALD) and the protective layer 132 may be formed by sputtering.

[0100] The ends of the pixel electrodes 111a, 111b, and 111c are not covered with an insulating layer, so the distance between adjacent light-emitting devices can be made extremely narrow, resulting in a high-definition or high-resolution display device.

[0101] In the display device of this embodiment, the light-emitting layers of each color are provided in an island shape for each light-emitting device, and the display device is fabricated by a so-called color-separate coating method (SBS (Side By Side) method). Therefore, a display device with higher light extraction efficiency can be realized compared to a configuration in which a white-emitting light-emitting device is combined with a color filter. In addition, since a single-structure light-emitting device can be applied, a display device with lower drive voltage can be realized compared to a configuration in which a tandem-structure light-emitting device is used. Furthermore, by using the SBS method, a display device with lower power consumption can be realized compared to a configuration in which a white-emitting light-emitting device is combined with a color filter and a configuration in which a tandem-structure light-emitting device is used.

[0102] The display device of the present embodiment can narrow the distance between the light-emitting devices. Specifically, the distance between the light-emitting devices can be 1 μm or less, preferably 500 nm or less, more preferably 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 10 nm or less. In other words, the distance between the side of the first layer 113a and the side of the second layer 113b, or the distance between the side of the second layer 113b and the side of the third layer 113c has an area of ​​1 μm or less, preferably an area of ​​0.5 μm (500 nm) or less, more preferably an area of ​​100 nm or less.

[0103] A light-shielding layer may be provided on the surface of the substrate 120 facing the resin layer 119. Various optical members may be arranged on the outside of the substrate 120. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light collecting film. An antistatic film that suppresses adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses the occurrence of scratches due to use, an impact absorbing layer, and the like may be arranged on the outside of the substrate 120.

[0104] The substrate 120 may be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, or the like. A material that transmits light is used for the substrate on the side from which light from the light-emitting device is extracted. When a flexible material is used for the substrate 120, the flexibility of the display device can be increased, and a flexible display can be realized. A polarizing plate may also be used for the substrate 120.

[0105] The substrate 120 may be made of polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. The substrate 120 may be made of glass having a thickness sufficient to provide flexibility.

[0106] When a circularly polarizing plate is laminated on a display device, it is preferable that the display device has a substrate having high optical isotropy. A substrate having high optical isotropy has small birefringence (it can also be said that the amount of birefringence is small).

[0107] The absolute value of the retardation (phase difference) value of a substrate having high optical isotropy is preferably 30 nm or less, more preferably 20 nm or less, and further preferably 10 nm or less.

[0108] Examples of films with high optical isotropy include triacetyl cellulose (TAC, also known as cellulose triacetate) films, cycloolefin polymer (COP) films, cycloolefin copolymer (COC) films, and acrylic films.

[0109] In addition, when a film is used as a substrate, the film may absorb water, causing deformation such as wrinkles on the display panel. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferably 0.1% or less, and even more preferably 0.01% or less.

[0110] For the resin layer 119, various types of curing adhesives can be used, such as a photo-curing adhesive such as an ultraviolet curing adhesive, a reaction curing adhesive, a heat curing adhesive, and an anaerobic adhesive. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenol resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. In particular, a material with low moisture permeability, such as epoxy resin, is preferable. A two-liquid mixed resin may also be used. An adhesive sheet or the like may also be used.

[0111] Note that a gap may exist between the fourth electron transport layer 116 and the electron injection layer 114. FIG. 1B shows an example in which the portion that may become a gap is filled with an insulator 134. Note that, depending on the distance between adjacent light-emitting devices, the thickness of the fourth electron transport layer 116, and the thickness of the electron injection layer 114, the gap may not be formed, and filling with the insulator 134 may not be necessary. In this case, the gap between adjacent light-emitting devices is filled with at least one of the fourth electron transport layer 116 and the electron injection layer 114.

[0112] The void contains, for example, one or more selected from air, nitrogen, oxygen, carbon dioxide, and a Group 18 element (typically, helium, neon, argon, xenon, krypton, etc.). The void may contain, for example, a gas used when forming the electron injection layer 114. For example, when the electron injection layer 114 is formed by a vacuum deposition method, the void may be in a reduced pressure atmosphere. When the void contains a gas, the gas can be identified by a gas chromatography method or the like.

[0113] Furthermore, when the refractive index of the void is lower than that of the fourth electron transport layer 116, the light emitted from the first layer 113a, the second layer 113b, or the third layer 113c is reflected at the interface between the fourth electron transport layer 116 and the void. This makes it possible to prevent the light emitted from the first layer 113a, the second layer 113b, or the third layer 113c from entering an adjacent pixel (or subpixel). This makes it possible to prevent light of different colors from being mixed together, thereby improving the display quality of the display device.

[0114] In addition, one or both of an organic insulating material and an inorganic insulating material can be used as the material for the insulator 134 that can be filled into the portions that can become voids. At least one of a solid material, a gel material, and a liquid material can be used as the insulator 134.

[0115] Examples of the organic insulating material include acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyimideamide resin, polysiloxane resin, benzocyclobutene resin, phenol resin, etc. Also, various resins that can be used for the resin layer 119 may be used.

[0116] Examples of the inorganic insulating material include an oxide insulating material, a nitride insulating material, an oxynitride insulating material, and a nitride oxide insulating material, etc. In addition, the insulating material that can be used for the protective layers 131 and 132 may be used.

[0117] Materials that can be used for the gate, source, and drain of a transistor as well as conductive layers such as various wirings and electrodes that constitute a display device include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, as well as alloys containing such metals as main components, etc. Films containing these materials can be used as a single layer or a laminated structure.

[0118] As the conductive material having light transmitting properties, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, or graphene can be used. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing the metal materials can be used. Alternatively, nitrides of the metal materials (for example, titanium nitride) may be used. Note that when using metal materials or alloy materials (or their nitrides), it is preferable to make them thin enough to have light transmitting properties. Also, a laminated film of the above materials can be used as the conductive layer. For example, it is preferable to use a laminated film of an alloy of silver and magnesium and indium tin oxide, because the conductivity can be increased. These can also be used for conductive layers such as various wirings and electrodes constituting a display device, and conductive layers (conductive layers functioning as pixel electrodes or common electrodes) of a light emitting device.

[0119] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0120] [Example of how to manufacture a display device] Next, an example of a method for manufacturing a display device will be described with reference to Fig. 2 to Fig. 7. Fig. 2A to Fig. 2C are top views showing a method for manufacturing a display device. Fig. 3A to Fig. 3C show a cross-sectional view taken along dashed line X1-X2 in Fig. 1A and a cross-sectional view taken along dashed line Y1-Y2 side by side. Fig. 4 to Fig. 7 are similar to Fig. 3.

[0121] The thin films (insulating film, semiconductor film, conductive film, etc.) constituting the display device can be formed by using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum deposition method, a pulsed laser deposition (PLD) method, an ALD method, etc. CVD methods include a plasma enhanced chemical vapor deposition (PECVD) method and a thermal CVD method. Another thermal CVD method is a metal organic chemical vapor deposition (MOCVD) method.

[0122] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, and knife coating.

[0123] In particular, for the production of light-emitting devices, vacuum processes such as deposition methods and solution processes such as spin coating and inkjet methods can be used. Examples of deposition methods include physical deposition methods (PVD methods) such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, and chemical deposition methods (CVD methods). In particular, functional layers (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, etc.) included in the EL layer can be formed by methods such as deposition methods (vacuum deposition methods, etc.), coating methods (dip coating, die coating, bar coating, spin coating, spray coating, etc.), printing methods (inkjet methods, screen (screen printing) methods, offset (lithographic printing) methods, flexo (relief printing) methods, gravure methods, microcontact methods, etc.).

[0124] In addition, when processing the thin film constituting the display device, a photolithography method or the like can be used. Alternatively, the thin film may be processed by a nanoimprint method, a sandblasting method, a lift-off method, or the like. Furthermore, an island-shaped thin film may be directly formed by a film formation method using a shielding mask such as a metal mask.

[0125] There are two typical photolithography methods. One is a method in which a resist mask is formed on the thin film to be processed, the thin film is processed by etching or the like, and the resist mask is then removed. The other is a method in which a photosensitive thin film is formed, and then exposed and developed to process the thin film into the desired shape.

[0126] In the photolithography method, the light used for exposure may be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. In addition, ultraviolet light, KrF laser light, ArF laser light, or the like may be used. Exposure may also be performed by immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays may also be used as the light used for exposure. An electron beam may also be used instead of the light used for exposure. Extreme ultraviolet light, X-rays, or an electron beam are preferable because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0127] For etching the thin film, a dry etching method, a wet etching method, a sandblasting method, or the like can be used.

[0128] First, as shown in FIG. 3A, a conductive film 111 is formed over a layer 101 including a transistor.

[0129] Then, a first hole injection layer 181A, a first hole transport layer 182A, a first light emitting layer 183A, and a first electron transport layer 184A are formed in this order on the conductive film 111, and a first sacrificial layer 118A is formed on the first electron transport layer 184A. As shown in Fig. 3A, in the cross-sectional view between Y1 and Y2, the ends of the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A on the connection portion 140 side are located inside the ends of the first sacrificial layer 118A. For example, by using a mask for defining the deposition area (also called an area mask or a rough metal mask to distinguish from a fine metal mask), it is possible to change the areas in which the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, the first electron transport layer 184A, and the first sacrificial layer 118A are deposited. In one embodiment of the present invention, a light-emitting device is formed using a resist mask, and by combining it with an area mask as described above, the light-emitting device can be manufactured by a relatively simple process.

[0130] The conductive film 111 is a layer that will be processed later to become the pixel electrodes 111a, 111b, and 111c, and the conductive layer 123. Therefore, the above-mentioned structure applicable to the pixel electrodes can be applied to the conductive film 111. The conductive film 111 can be formed by, for example, a sputtering method or a vacuum evaporation method.

[0131] The first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A are layers that will later become the first hole injection layer 181a, the first hole transport layer 182a, the first light emitting layer 183a, and the first electron transport layer 184a, respectively. Therefore, the above-mentioned configurations applicable to the first hole injection layer 181a, the first hole transport layer 182a, the first light emitting layer 183a, and the first electron transport layer 184a can be applied. The first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A can be formed by a method such as a deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, or a coating method. In addition, first hole injection layer 181A, first hole transport layer 182A, first light emitting layer 183A, and first electron transport layer 184A may each be formed using a premix material.

[0132] The first sacrificial layer 118A is made of a film having high resistance to processing conditions, specifically, a film having a large etching selectivity, for the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A, as well as the second hole injection layer 181B, the second hole transport layer 182B, the second light emitting layer 183B, and the second electron transport layer 184B, the third hole injection layer 181C, the third hole transport layer 182C, the third light emitting layer 183C, and the third electron transport layer 184C, which are to be formed in a later step. The first sacrificial layer 118A may have a single layer structure or a laminated structure.

[0133] The first sacrificial layer 118A can be formed by, for example, sputtering, ALD (including thermal ALD and PEALD), or vacuum deposition. Note that a formation method that causes less damage to the EL layer is preferable, and it is preferable to form the first sacrificial layer 118A by using the ALD or vacuum deposition rather than the sputtering method.

[0134] It is preferable to use a film that can be removed by wet etching for the first sacrificial layer 118A. By using the wet etching method, damage to the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A during processing of the first sacrificial layer 118A can be reduced compared to the case of using the dry etching method.

[0135] In the process of processing the various sacrificial layers in the manufacturing method of the display device of this embodiment, it is desirable that the layers constituting the EL layer (such as the hole injection layer, the hole transport layer, the light emitting layer, and the electron transport layer) are not easily processed, and it is also desirable that the various sacrificial layers are not easily processed in the process of processing the layers constituting the EL layer. It is desirable to select the material and processing method of the sacrificial layer and the processing method of the EL layer taking these factors into consideration.

[0136] As the first sacrificial layer 118A, for example, a metal film, an alloy film, a metal oxide film, a semiconductor film, or an inorganic film such as an inorganic insulating film can be used.

[0137] The first sacrificial layer 118A can be made of a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or an alloy material containing such a metal material.

[0138] Moreover, metal oxides such as In-Ga-Zn oxide can be used for the first sacrificial layer 118A. For example, an In-Ga-Zn oxide film can be formed as the first sacrificial layer 118A by using a sputtering method. Furthermore, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc. can be used. Alternatively, indium tin oxide containing silicon can be used.

[0139] In addition, instead of the above gallium, an element M (M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) may be used.

[0140] Moreover, the first sacrificial layer 118A can be made of any of various inorganic insulating films that can be used for the protective layers 131 and 132. In particular, an oxide insulating film is preferable because it has higher adhesion to the EL layer than a nitride insulating film. For example, the first sacrificial layer 118A can be made of an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide. For example, an aluminum oxide film can be formed as the first sacrificial layer 118A by using the ALD method. The ALD method is preferable because it can reduce damage to the underlayer (particularly the EL layer, etc.).

[0141] 3B, a resist mask 190a is formed on the first sacrificial layer 118A. The resist mask can be formed by applying a photosensitive resin (photoresist) and performing exposure and development.

[0142] As shown in FIG. 2A, the resist mask 190a is provided at a position overlapping with a region that will later become the subpixel 110a. Furthermore, the resist mask 190a is preferably provided at a position overlapping with a region that will later become the connection portion 140. This can prevent a region of the conductive film 111 that will later become the conductive layer 123 from being damaged during the manufacturing process of the display device. The resist mask 190a is preferably provided with one island-shaped pattern for one subpixel 110a. Alternatively, the resist mask 190a may be formed with one strip-shaped pattern for a plurality of subpixels 110a arranged in a line (arranged in the Y direction in FIG. 2A).

[0143] 3C, a part of the first hole injection layer 181A, a part of the first hole transport layer 182A, a part of the first light emitting layer 183A, a part of the first electron transport layer 184A, and a part of the first sacrificial layer 118A are removed using the resist mask 190a. This makes it possible to remove the regions of the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, the first electron transport layer 184A, and the first sacrificial layer 118A that do not overlap with the resist mask 190a. Therefore, a part of the conductive film 111 is exposed. In a region corresponding to the subpixel 110a, a stacked structure of the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, the first electron transport layer 184a, the first sacrificial layer 118a, and the resist mask 190a remains on the conductive film 111. In a region corresponding to the connection portion 140, a stacked structure of the first sacrificial layer 118a and the resist mask 190a remains on the conductive film 111. Note that the stacked structure of the first hole injection layer 181a, the first hole transport layer 182a, the first light-emitting layer 183a, and the first electron transport layer 184a is also referred to as the first layer 113a. Then, the resist mask 190a is removed.

[0144] The first sacrificial layer 118A can be processed by a wet etching method or a dry etching method. The first sacrificial layer 118A is preferably processed by anisotropic etching.

[0145] By using the wet etching method, damage to the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A during processing of the first sacrificial layer 118A can be reduced compared to the case of using the dry etching method. When using the wet etching method, it is preferable to use a chemical solution using, for example, a developer, a tetramethylammonium hydroxide (TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture of these.

[0146] In addition, when dry etching is used, deterioration of the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A can be suppressed by not using a gas containing oxygen as an etching gas. 4 , C 4 F 8 ,SCIENCE FICTION 6 , CHF 3 , Cl 2 , H 2 O, BCl 3 It is preferable to use a gas containing a noble gas (also called a rare gas) such as He or the like as an etching gas.

[0147] 3C shows an example in which the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, the first electron transport layer 184A, and the first sacrificial layer 118A are processed while the resist mask 190a is left, but the present invention is not limited to this. For example, when the first sacrificial layer 118A has a laminated structure, some layers may be processed using the resist mask 190a, and after removing the resist mask 190a, the remaining layers may be processed using the some layers as a hard mask.

[0148] For example, after processing a portion of the first sacrificial layer 118A using the resist mask 190a, the resist mask 190a is removed by ashing using oxygen plasma or the like. At this time, the remaining layer of the first sacrificial layer 118A is located on the outermost surface, and the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A are not exposed, so that damage to the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A can be suppressed in the process of removing the resist mask 190a. Then, a portion of the processed first sacrificial layer 118A can be used as a hard mask to process the remaining layers of first sacrificial layer 118A, as well as first hole injection layer 181A, first hole transport layer 182A, first light-emitting layer 183A, and first electron transport layer 184A.

[0149] The first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A are preferably processed by anisotropic etching. In particular, anisotropic dry etching is preferable. As the etching gas, it is preferable to use a gas containing nitrogen, a gas containing hydrogen, a gas containing a noble gas, a gas containing nitrogen and argon, or a gas containing nitrogen and hydrogen. By not using a gas containing oxygen as the etching gas, deterioration of the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A can be suppressed.

[0150] Moreover, a gas containing oxygen may be used as the etching gas. When the etching gas contains oxygen, the etching speed can be increased. Therefore, etching can be performed under low power conditions while maintaining a sufficiently high etching speed. Therefore, damage to the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A can be suppressed. Furthermore, defects such as adhesion of reaction products generated during etching can be suppressed.

[0151] Next, as shown in Fig. 4A, a second hole injection layer 181B, a second hole transport layer 182B, a second light emitting layer 183B, and a second electron transport layer 184B are formed in this order on the first sacrificial layer 118a and the conductive film 111, and a second sacrificial layer 118B is formed on the second electron transport layer 184B. As shown in Fig. 4A, in the cross-sectional view between Y1 and Y2, the ends of the second hole injection layer 181B, the second hole transport layer 182B, the second light emitting layer 183B, and the second electron transport layer 184B on the connection portion 140 side are located inside the ends of the second sacrificial layer 118B.

[0152] The second hole injection layer 181B, the second hole transport layer 182B, the second light emitting layer 183B, and the second electron transport layer 184B are layers that will later become the second hole injection layer 181b, the second hole transport layer 182b, the second light emitting layer 183b, and the second electron transport layer 184b, respectively. The second light emitting layer 183b emits light of a different color from the first light emitting layer 183a. The configurations and materials that can be applied to the second hole injection layer 181b, the second hole transport layer 182b, the second light emitting layer 183b, and the second electron transport layer 184b are similar to those of the first hole injection layer 181a, the first hole transport layer 182a, the first light emitting layer 183a, and the first electron transport layer 184a, respectively. The second hole transport layer 182B, the second light-emitting layer 183B, and the second electron transport layer 184B can be formed using a method similar to that for the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A, respectively.

[0153] The second sacrificial layer 118B can be formed using a material that is applicable to the first sacrificial layer 118A.

[0154] Next, as shown in FIG. 4B, a resist mask 190b is formed on the second sacrificial layer 118B.

[0155] As shown in FIG. 2B, the resist mask 190b is provided at a position overlapping with a region that will later become the subpixel 110b. Furthermore, the resist mask 190b is preferably provided at a position overlapping with a region that will later become the connection portion 140. This can prevent a region of the conductive film 111 that will later become the conductive layer 123 from being damaged during a manufacturing process of the display device. Note that when the first sacrificial layer 118a is provided in a region that will later become the connection portion 140, the resist mask 190b does not need to be provided in that region. It is preferable that the resist mask 190b has one island-shaped pattern for one subpixel 110b. Alternatively, the resist mask 190b may have one stripe-shaped pattern for a plurality of subpixels 110b arranged in a row.

[0156] 4C, a part of the second hole injection layer 181B, a part of the second hole transport layer 182B, a part of the second light emitting layer 183B, a part of the second electron transport layer 184B, and a part of the second sacrificial layer 118B are removed using the resist mask 190b. This makes it possible to remove the regions of the second hole injection layer 181B, the second hole transport layer 182B, the second light emitting layer 183B, the second electron transport layer 184B, and the second sacrificial layer 118B that do not overlap with the resist mask 190b. Therefore, a part of the conductive film 111 is exposed. In a region corresponding to the subpixel 110b, a stacked structure of the second hole injection layer 181b, the second hole transport layer 182b, the second light-emitting layer 183b, the second electron transport layer 184b, the second sacrificial layer 118b, and the resist mask 190b remains on the conductive film 111. In a region corresponding to the connection portion 140, a stacked structure of the first sacrificial layer 118a, the second sacrificial layer 118b, and the resist mask 190b remains on the conductive film 111. Note that the stacked structure of the second hole injection layer 181b, the second hole transport layer 182b, the second light-emitting layer 183b, and the second electron transport layer 184b is also referred to as the second layer 113b. Then, the resist mask 190b is removed.

[0157] The second sacrificial layer 118B can be processed using a method applicable to processing the first sacrificial layer 118A. The second hole injection layer 181B, the second hole transport layer 182B, the second light emitting layer 183B, and the second electron transport layer 184B can be processed using a method applicable to processing the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A. The resist mask 190b can be removed by a method and timing applicable to removing the resist mask 190a.

[0158] Next, as shown in Fig. 5A, a third hole injection layer 181C, a third hole transport layer 182C, a third light emitting layer 183C, and a third electron transport layer 184C are formed in this order on the first sacrificial layer 118a, the second sacrificial layer 118b, and the conductive film 111, and a third sacrificial layer 118C is formed on the third electron transport layer 184C. As shown in Fig. 5A, in the cross-sectional view between Y1-Y2, the ends of the third hole injection layer 181C, the third hole transport layer 182C, the third light emitting layer 183C, and the third electron transport layer 184C on the connection portion 140 side are located inside the ends of the third sacrificial layer 118C.

[0159] The third hole injection layer 181C, the third hole transport layer 182C, the third light emitting layer 183C, and the third electron transport layer 184C are layers that will later become the third hole injection layer 181c, the third hole transport layer 182c, the third light emitting layer 183c, and the third electron transport layer 184c, respectively. The third light emitting layer 183c emits light of a different color from the first light emitting layer 183a and the second light emitting layer 183b. The configurations and materials that can be applied to the third hole injection layer 181c, the third hole transport layer 182c, the third light emitting layer 183c, and the third electron transport layer 184c are similar to those of the first hole injection layer 181a, the first hole transport layer 182a, the first light emitting layer 183a, and the first electron transport layer 184a, respectively. The third hole injection layer 181C, the third hole transport layer 182C, the third light-emitting layer 183C, and the third electron transport layer 184C can be formed using a method similar to that for the first hole injection layer 181A, the first hole transport layer 182A, the first light-emitting layer 183A, and the first electron transport layer 184A, respectively.

[0160] The third sacrificial layer 118C can be formed using a material applicable to the first sacrificial layer 118A.

[0161] Next, as shown in FIG. 5B, a resist mask 190c is formed on the third sacrificial layer 118C.

[0162] As shown in FIG. 2C, the resist mask 190c is provided at a position overlapping with a region that will later become the sub-pixel 110c. As the resist mask 190c, it is preferable that one island-shaped pattern is provided for one sub-pixel 110c. Alternatively, as the resist mask 190c, one strip-shaped pattern may be formed for a plurality of sub-pixels 110c arranged in a row. Furthermore, it is preferable that the resist mask 190c is also provided at a position overlapping with a region that will later become the connection portion 140. Note that, when at least one of the first sacrificial layer 118a and the second sacrificial layer 118b is provided in the region that will later become the connection portion 140, the resist mask 190c does not need to be provided in that region.

[0163] 5C, a part of the third hole injection layer 181C, a part of the third hole transport layer 182C, a part of the third light emitting layer 183C, a part of the third electron transport layer 184C, and a part of the third sacrificial layer 118C are removed using the resist mask 190c. This makes it possible to remove the regions of the third hole injection layer 181C, the third hole transport layer 182C, the third light emitting layer 183C, the third electron transport layer 184C, and the third sacrificial layer 118C that do not overlap with the resist mask 190c. Then, in the region corresponding to the subpixel 110c, a stacked structure of the third hole injection layer 181c, the third hole transport layer 182c, the third light emitting layer 183c, the third electron transport layer 184c, the third sacrificial layer 118c, and the resist mask 190c remains on the conductive film 111. In addition, in a region corresponding to the connection portion 140, a stacked structure of the first sacrificial layer 118a, the second sacrificial layer 118b, the third sacrificial layer 118c, and the resist mask 190c remains on the conductive film 111. Note that the stacked structure of the third hole injection layer 181c, the third hole transport layer 182c, the third light-emitting layer 183c, and the third electron transport layer 184c is also referred to as a third layer 113c. Then, as shown in FIG. 6A, the resist mask 190c is removed.

[0164] The third sacrificial layer 118C can be processed using a method applicable to processing the first sacrificial layer 118A. The third hole injection layer 181C, the third hole transport layer 182C, the third light emitting layer 183C, and the third electron transport layer 184C can be processed using a method applicable to processing the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, and the first electron transport layer 184A. The resist mask 190c can be removed by a method and timing applicable to removing the resist mask 190a.

[0165] Next, as shown in FIG. 6B, the conductive film 111 is processed using the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c as a hard mask to form pixel electrodes 111a, 111b, and 111c, and a conductive layer 123.

[0166] When the conductive film 111 is processed, a part of the layer 101 including a transistor (specifically, an insulating layer located at the outermost surface) may be processed to form a recess. In the following description, a case where a recess is provided in the layer 101 including a transistor will be described as an example, but the recess is not necessarily required.

[0167] Here, in order to form the conductive layer 123, at least the third sacrificial layer 118c is required to be provided in the connection portion 140. On the other hand, as described above, by providing the connection portion 140 with a stacked structure of the second sacrificial layer 118b and the third sacrificial layer 118c or a stacked structure of the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c, a region of the conductive film 111 that becomes the conductive layer 123 can be prevented from being damaged during the manufacturing process of the display device, which is preferable.

[0168] The conductive film 111 can be processed by a wet etching method or a dry etching method. The conductive film 111 is preferably processed by anisotropic etching.

[0169] 6C, the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c are removed. As a result, the first electron transport layer 184a is exposed on the pixel electrode 111a, the second electron transport layer 184b is exposed on the pixel electrode 111b, the third electron transport layer 184c is exposed on the pixel electrode 111c, and the conductive layer 123 is exposed in the connection portion 140.

[0170] The sacrificial layer removal step can be performed using the same method as the sacrificial layer processing step. In particular, by using a wet etching method, damage to the first layer 113a, the second layer 113b, and the third layer 113c can be reduced when removing the first sacrificial layer 118a, the second sacrificial layer 118b, and the third sacrificial layer 118c, compared to the case of using a dry etching method.

[0171] Next, as shown in Fig. 7A, a fourth electron transport layer 116 is formed so as to cover the first layer 113a, the second layer 113b, and the third layer 113c. As shown in Fig. 7A, in the cross-sectional view between Y1 and Y2, the end of the fourth electron transport layer 116 on the connection portion 140 side is located inside the connection portion 140, and the conductive layer 123 remains exposed.

[0172] The materials that can be used for the fourth electron transport layer 116 are as described above. The fourth electron transport layer 116 can be formed by a method such as a deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, or a coating method. The fourth electron transport layer 116 may be formed using a premix material.

[0173] The fourth electron transport layer 116 is formed using a material having higher insulating properties than the electron injection layer 114 to be formed next. The fourth electron transport layer 116 is provided so as to cover the upper and side surfaces of the first layer 113a, the second layer 113b, and the third layer 113c, and the side surfaces of the pixel electrodes 111a, 111b, and 111c, and therefore prevents the highly conductive electron injection layer 114 from coming into contact with these layers, thereby preventing the light-emitting device from shorting out. This can improve the reliability of the light-emitting device.

[0174] In particular, it is preferable that a recess is provided in a part of the layer 101 including the transistor (specifically, the insulating layer located on the outermost surface), since this makes it possible to cover the entire side surfaces of the pixel electrodes 111a, 111b, and 111c with the fourth electron transport layer 116.

[0175] Next, as shown in Fig. 7B, the electron injection layer 114 is formed on the fourth electron transport layer 116. As shown in Fig. 7B, in the cross-sectional view between Y1 and Y2, the end of the electron injection layer 114 on the connection portion 140 side is located inside the connection portion 140, and the conductive layer 123 remains exposed.

[0176] The materials that can be used for the electron injection layer 114 are as described above. The electron injection layer 114 can be formed by a method such as a vapor deposition method (including a vacuum deposition method), a transfer method, a printing method, an inkjet method, or a coating method. The electron injection layer 114 may also be formed using a premix material.

[0177] Here, an example is shown in which the gap 133 is formed by the deposition of the electron injection layer 114, but the gap 133 does not have to be formed. In this case, the space between the two light-emitting devices is filled with the electron injection layer 114. Alternatively, the space between the two light-emitting devices may be filled with the fourth electron transport layer 116 before the deposition of the electron injection layer 114.

[0178] 7C, the portions that may become voids 133 may be filled in advance with insulator 134. Details of voids 133 and insulator 134 are as described above.

[0179] Then, a common electrode 115 is formed on the electron injection layer 114 .

[0180] The above-mentioned materials can be used for the common electrode 115. The common electrode 115 can be formed by, for example, sputtering or vacuum deposition.

[0181] Thereafter, protective layer 131 is formed on common electrode 115, and protective layer 132 is formed on protective layer 131. Furthermore, substrate 120 is bonded onto protective layer 132 using resin layer 119, whereby display device 100 shown in FIG. 1B can be manufactured.

[0182] The materials and film formation methods that can be used for the protective layers 131 and 132 are as described above. Film formation methods for the protective layers 131 and 132 include vacuum deposition, sputtering, CVD, and ALD. The protective layers 131 and 132 may be films formed using different film formation methods. Furthermore, each of the protective layers 131 and 132 may have a single-layer structure or a multilayer structure.

[0183] As described above, in the manufacturing method of the display device of this embodiment, the island-shaped EL layer is not formed using a fine metal mask, but is formed by depositing the EL layer over an entire surface and then processing it, so that the island-shaped EL layer can be formed with a uniform thickness.

[0184] The first, second, and third layers that make up the light-emitting device of each color are formed in separate processes. Therefore, each EL layer can be fabricated with a configuration (material, film thickness, etc.) that is suitable for the light-emitting device of each color. This allows the fabrication of light-emitting devices with good characteristics.

[0185] A display device according to one embodiment of the present invention has an island-shaped first electron transport layer over a light-emitting layer, and further has a second electron transport layer covering each side surface of a pixel electrode, a light-emitting layer, and the first electron transport layer. In a manufacturing process of the display device, the EL layer is processed in a state in which the light-emitting layer and the first electron transport layer are stacked, so that the display device has a structure in which damage to the light-emitting layer is reduced. In addition, the second electron transport layer prevents the pixel electrode from contacting the electron injection layer or the common electrode, thereby preventing a short circuit of the light-emitting device.

[0186] This embodiment mode can be combined with other embodiment modes as appropriate. In addition, in the case where a plurality of configuration examples are shown in one embodiment mode in this specification, the configuration examples can be combined as appropriate.

[0187] (Embodiment 2) In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0188] The display device of the present embodiment can be a high-definition display device. Therefore, the display device of the present embodiment can be used for a display unit of a wearable device that can be worn on the head, such as a wristwatch-type or bracelet-type information terminal (wearable device), a head-mounted display or other VR device, or a glasses-type AR device.

[0189] [Display module] 8A shows a perspective view of a display module 280. The display module 280 has a display device 100A and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100A, and may be a display device 100B or a display device 100C described later.

[0190] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display unit 281. The display unit 281 is a region that displays an image in the display module 280, and is a region where light from each pixel provided in a pixel unit 284 described later can be viewed.

[0191] 8B is a perspective view showing a schematic configuration of the substrate 291 side. On the substrate 291, a circuit section 282, a pixel circuit section 283 on the circuit section 282, and a pixel section 284 on the pixel circuit section 283 are laminated. In addition, a terminal section 285 for connecting to an FPC 290 is provided in a portion of the substrate 291 that does not overlap with the pixel section 284. The terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286 consisting of a plurality of wirings.

[0192] 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. 8B. The pixel 284a has light emitting devices 130a, 130b, and 130c that emit different light colors. In this embodiment, the pixel 284a is configured with a light emitting device 130a that emits red light, a light emitting device 130b that emits green light, and a light emitting device 130c that emits blue light. The plurality of light emitting devices can be arranged in a stripe array as shown in FIG. 8B. In addition, various light emitting device arrangement methods such as a delta array or a pentile array can be applied.

[0193] Here, when a pixel of a display device has three types of subpixels having light-emitting devices that emit light of different colors, the three subpixels include subpixels of three colors R, G, and B, and subpixels of three colors yellow (Y), cyan (C), and magenta (M), etc. When a pixel of a display device has four subpixels, the four subpixels include subpixels of four colors R, G, B, and white (W), and subpixels of four colors R, G, B, and Y, etc.

[0194] The pixel circuit section 283 has a plurality of pixel circuits 283a that are periodically arranged.

[0195] One pixel circuit 283a is a circuit that controls the light emission of three light emitting devices included in one pixel 284a. One pixel circuit 283a may be configured to have three circuits that control the light emission of one light emitting device. For example, the pixel circuit 283a may be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitance element for each light emitting device. At this time, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain. This realizes an active matrix display device.

[0196] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. In addition, either a top-gate type or a bottom-gate type transistor may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0197] The crystallinity of a semiconductor material used in a transistor is not particularly limited, and any of an amorphous semiconductor, a single crystal semiconductor, and a semiconductor having crystallinity other than single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single crystal semiconductor or a semiconductor having crystallinity is preferable because it can suppress deterioration of transistor characteristics.

[0198] The semiconductor layer of the transistor preferably contains metal oxide (also referred to as an oxide semiconductor). That is, the display device of this embodiment preferably contains a transistor in which a channel formation region is formed using metal oxide (hereinafter, referred to as an OS transistor). Alternatively, the semiconductor layer of the transistor preferably contains silicon. Examples of silicon include amorphous silicon, crystalline silicon (low-temperature polysilicon, single crystal silicon, or the like), and the like.

[0199] The semiconductor layer preferably contains, for example, indium, M (M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin.

[0200] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) as the semiconductor layer.

[0201] When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. Examples of atomic ratios of metal elements in such In-M-Zn oxides include In:M:Zn=1:1:1 or a composition thereabout, In:M:Zn=1:1:1.2 or a composition thereabout, In:M:Zn=2:1:3 or a composition thereabout, In:M:Zn=3:1:2 or a composition thereabout, In:M:Zn=4:2:3 or a composition thereabout, In:M:Zn=4:2:4.1 or a composition thereabout, In:M:Zn=5:1:3 or a composition thereabout, In:M:Zn=5:1:6 or a composition thereabout, In:M:Zn=5:1:7 or a composition thereabout, In:M:Zn=5:1:8 or a composition thereabout, In:M:Zn=6:1:6 or a composition thereabout, In:M:Zn=5:2:5 or a composition thereabout, etc. The term "nearby composition" includes a range of ±30% of the desired atomic ratio.

[0202] For example, when describing a composition with an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, it includes cases where, when In is 4, Ga is 1 to 3 and Zn is 2 to 4. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, it includes cases where, when In is 5, Ga is greater than 0.1 and less than 2 and Zn is greater than 5 and less than 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, it includes cases where, when In is 1, Ga is greater than 0.1 and less than 2 and Zn is greater than 0.1 and less than 2.

[0203] The transistors included in the circuit portion 282 and the transistors included in the pixel circuit portion 283 may have the same structure or different structures. The transistors included in the circuit portion 282 may all have the same structure or may have two or more types. Similarly, the transistors included in the pixel circuit portion 283 may all have the same structure or may have two or more types.

[0204] The circuit portion 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like.

[0205] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit portion 282. In addition, an IC (integrated circuit) may be mounted on the FPC 290.

[0206] The display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are provided overlappingly under the pixel section 284, so that the aperture ratio (effective display area ratio) of the display section 281 can be extremely high. For example, the aperture ratio of the display section 281 can be set to 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. In addition, the pixels 284a can be arranged at an extremely high density, so that the resolution of the display section 281 can be extremely high. For example, it is preferable that the pixels 284a are arranged in the display section 281 at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20000 ppi or less, or 30000 ppi or less.

[0207] Such a display module 280 is extremely high-definition and can be suitably used in VR devices such as head-mounted displays or glasses-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through a lens, the display module 280 has an extremely high-definition display unit 281, so that even if the display unit is enlarged with a lens, pixels are not visible, and a highly immersive display can be performed. In addition, the display module 280 is not limited to this, and can be suitably used in electronic devices having a relatively small display unit. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0208] [Display device 100A] The display device 100A shown in FIG. 9 includes a substrate 301, light emitting devices 130a, 130b, and 130c, a capacitor 240, and a transistor 310.

[0209] 8A and 8B. The stacked structure from the substrate 301 to the insulating layer 255 corresponds to the layer 101 including a transistor in the first embodiment.

[0210] The transistor 310 has a channel formation region in a substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities, and functions as one of a source and a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0211] In addition, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0212] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided on the insulating layer 261 .

[0213] Capacitor 240 has conductive layer 241, conductive layer 245, and insulating layer 243 located therebetween. Conductive layer 241 functions as one electrode of capacitor 240, conductive layer 245 functions as the other electrode of capacitor 240, and insulating layer 243 functions as a dielectric of capacitor 240.

[0214] The conductive layer 241 is provided over the insulating layer 261 and is embedded in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and the drain of the transistor 310 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 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0215] An insulating layer 255 is provided to cover the capacitor 240, and light emitting devices 130a, 130b, 130c, etc. are provided on the insulating layer 255. In this embodiment, an example is shown in which the light emitting devices 130a, 130b, 130c have the same structure as the stacked structure shown in FIG. 1B. A protective layer 131 is provided on each of the light emitting devices 130a, 130b, 130c. A protective layer 132 is provided on the protective layer 131, and a substrate 120 is bonded to the protective layer 132 by a resin layer 119. An insulator 134 is filled between the fourth electron transport layer 116 and the electron injection layer 114. For details of the components from the light emitting device to the substrate 120, refer to the first embodiment. The substrate 120 corresponds to the substrate 292 in FIG. 8A.

[0216] The pixel electrode of the light-emitting device is electrically connected to either the source or drain of transistor 310 by a plug 256 embedded in insulating layer 255, a conductive layer 241 embedded in insulating layer 254, and a plug 271 embedded in insulating layer 261.

[0217] [Display device 100B] 10 is different from the display device 100A mainly in the configuration of the transistors, Note that a description of the same parts as those of the display device 100A may be omitted.

[0218] The transistor 320 is a transistor (OS transistor) in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

[0219] The transistor 320 includes a semiconductor layer 321 , an insulating layer 323 , a conductive layer 324 , a pair of conductive layers 325 , an insulating layer 326 , and a conductive layer 327 .

[0220] 8A and 8B. The stacked structure from the substrate 331 to the insulating layer 255 corresponds to the layer 101 including the transistor in Embodiment 1. The substrate 331 can be an insulating substrate or a semiconductor substrate.

[0221] An insulating layer 332 is provided over a substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320 and prevents oxygen from being released from the semiconductor layer 321 toward the insulating layer 332. As the insulating layer 332, for example, a film through which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film, can be used.

[0222] A conductive layer 327 is provided over the insulating layer 332, and an insulating layer 326 is provided to cover the conductive layer 327. The conductive layer 327 functions as a first gate electrode of the transistor 320, and part of the insulating layer 326 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a portion of the insulating layer 326 that is in contact with the semiconductor layer 321. The top surface of the insulating layer 326 is preferably planarized.

[0223] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide (also referred to as an oxide semiconductor) film having semiconductor characteristics. Details of materials that can be suitably used for the semiconductor layer 321 will be described later.

[0224] A pair of conductive layers 325 is provided on and in contact with the semiconductor layer 321 and functions as a source electrode and a drain electrode.

[0225] Further, an insulating layer 328 is provided to cover top surfaces and side surfaces of the pair of conductive layers 325 and side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided over the insulating layer 328. The insulating layer 328 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing from the insulating layer 264 or the like to the semiconductor layer 321 and to prevent oxygen from being released from the semiconductor layer 321. As the insulating layer 328, an insulating film similar to the insulating layer 332 can be used.

[0226] An opening reaching the semiconductor layer 321 is provided in the insulating layer 328 and the insulating layer 264. An insulating layer 323 and a conductive layer 324 are buried inside the opening, the insulating layer 323 being in contact with the side surfaces of the insulating layer 264, the insulating layer 328, and the conductive layer 325 and the upper surface of the semiconductor layer 321. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0227] The upper surface of conductive layer 324, the upper surface of insulating layer 323, and the upper surface of insulating layer 264 are flattened so that their heights are roughly the same, and insulating layers 329 and 265 are provided covering these.

[0228] The insulating layers 264 and 265 function as interlayer insulating layers. The insulating layer 329 functions as a barrier layer for preventing impurities such as water or hydrogen from diffusing from the insulating layer 265 or the like to the transistor 320. The insulating layer 329 can be an insulating film similar to the insulating layers 328 and 332.

[0229] A plug 274 electrically connected to one of the pair of conductive layers 325 is provided so as to be embedded in the insulating layer 265, the insulating layer 329, and the insulating layer 264. Here, the plug 274 preferably has a conductive layer 274a covering side surfaces of the openings of the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328 and a part of the upper surface of the conductive layer 325, and a conductive layer 274b in contact with the upper surface of the conductive layer 274a. In this case, it is preferable to use a conductive material through which hydrogen and oxygen are unlikely to diffuse as the conductive layer 274a.

[0230] In addition, the layer 101 including a transistor may have various inorganic insulating films. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. A hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may also be used. Two or more of the above insulating films may be stacked.

[0231] In the display device 100B, the configuration from the insulating layer 254 to the substrate 120 is similar to that of the display device 100A.

[0232] [Display device 100C] 11 has a stacked structure of a transistor 310 in which a channel is formed in a substrate 301 and a transistor 320 in which a semiconductor layer in which a channel is formed contains a metal oxide. Note that descriptions of the same parts as those of the display devices 100A and 100B may be omitted.

[0233] An insulating layer 261 is provided to cover the transistor 310, and a conductive layer 251 is provided over the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided over the insulating layer 262. The conductive layer 251 and the conductive layer 252 each function as a wiring. An insulating layer 263 and an insulating layer 332 are provided to cover the conductive layer 252, and a transistor 320 is provided over the insulating layer 332. An insulating layer 265 is provided to cover the transistor 320, and a capacitor 240 is provided over the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected to each other through a plug 274.

[0234] The transistor 320 can be used as a transistor that constitutes a pixel circuit. The transistor 310 can be used as a transistor that constitutes a pixel circuit or a driver circuit (gate line driver circuit, source line driver circuit) for driving the pixel circuit. The transistors 310 and 320 can be used as transistors that constitute various circuits such as an arithmetic circuit or a memory circuit.

[0235] With this configuration, not only pixel circuits but also driving circuits, etc. can be formed directly below the light-emitting device, making it possible to reduce the size of the display device compared to when driving circuits are provided around the periphery of the display area.

[0236] This embodiment mode can be combined with other embodiment modes as appropriate.

[0237] (Embodiment 3) In this embodiment, a light-emitting device that can be used for a display device of one embodiment of the present invention will be described.

[0238] The light-emitting device shown in Fig. 12A has an electrode 772, an EL layer 786, and an electrode 788. One of the electrodes 772 and 788 functions as an anode, and the other functions as a cathode. In addition, one of the electrodes 772 and 788 functions as a pixel electrode, and the other functions as a common electrode. In addition, it is preferable that the electrode from which light is extracted, of the electrodes 772 and 788, is transparent to visible light, and the other electrode reflects visible light.

[0239] 12A, the EL layer 786 of the light-emitting device can be composed of a plurality of layers such as a layer 4420, a light-emitting layer 4411, and a layer 4430. The layer 4420 can have, for example, a layer including a substance with high electron injection properties (electron injection layer) and a layer including a substance with high electron transport properties (electron transport layer). The light-emitting layer 4411 has, for example, a light-emitting compound. The layer 4430 can have, for example, a layer including a substance with high hole injection properties (hole injection layer) and a layer including a substance with high hole transport properties (hole transport layer).

[0240] A structure including the layer 4420, the light-emitting layer 4411, and the layer 4430 provided between a pair of electrodes can function as a single light-emitting unit, and the structure of FIG. 12A is referred to as a single structure in this specification.

[0241] 12B is a modified example of the EL layer 786 of the light-emitting device shown in FIG. 12A. Specifically, the light-emitting device shown in FIG. 12B has a layer 4431 on an electrode 772, a layer 4432 on the layer 4431, a light-emitting layer 4411 on the layer 4432, a layer 4421 on the light-emitting layer 4411, a layer 4422 on the layer 4421, and an electrode 788 on the layer 4422. For example, when the electrode 772 is an anode and the electrode 788 is a cathode, the layer 4431 functions as a hole injection layer, the layer 4432 functions as a hole transport layer, the layer 4421 functions as an electron transport layer, and the layer 4422 functions as an electron injection layer. Alternatively, when the electrode 772 is a cathode and the electrode 788 is an anode, the layer 4431 functions as an electron injecting layer, the layer 4432 functions as an electron transporting layer, the layer 4421 functions as a hole transporting layer, and the layer 4422 functions as a hole injecting layer. With such a layer structure, carriers can be efficiently injected into the light-emitting layer 4411, and the efficiency of carrier recombination in the light-emitting layer 4411 can be increased.

[0242] As shown in FIG. 12C, a configuration in which a plurality of light-emitting layers (light-emitting layers 4411, 4412, 4413) are provided between layer 4420 and layer 4430 is also a variation of the single structure.

[0243] As shown in FIG. 12D, a configuration in which a plurality of light-emitting units (EL layers 786a, 786b) are connected in series via an intermediate layer 4440 (also referred to as a charge generation layer) is referred to as a tandem structure in this specification. Note that this is not limiting, and for example, the tandem structure may be referred to as a stack structure. Note that the tandem structure can provide a light-emitting device capable of emitting light with high luminance.

[0244] 12C and 12D, the layer 4420 and the layer 4430 can each have a laminated structure made up of two or more layers as shown in FIG. 12B.

[0245] The emission color of the light emitting device can be red, green, blue, cyan, magenta, yellow, or white, depending on the material that constitutes the EL layer 786. In addition, the color purity can be further improved by providing the light emitting device with a microcavity structure.

[0246] A light-emitting device that emits white light preferably has a structure in which the light-emitting layer contains two or more kinds of light-emitting materials. To obtain white light emission, it is sufficient to select light-emitting materials whose respective lights emitted from the two or more light-emitting materials have a complementary color relationship. For example, a light-emitting device that emits white light as a whole can be obtained by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer have a complementary color relationship. The same is true for a light-emitting device having three or more light-emitting layers. For example, if the light-emitting colors of the light-emitting layers 4411, 4412, and 4413 shown in FIG. 12C are complementary colors, a single-structure white light-emitting device can be realized.

[0247] The light-emitting layer preferably contains two or more light-emitting materials that emit light of R (red), G (green), B (blue), Y (yellow), O (orange), etc. Alternatively, it is preferable that the light-emitting layer contains two or more light-emitting materials, and the light emitted by each of the light-emitting materials contains spectral components of two or more colors of R, G, and B.

[0248] This embodiment mode can be combined with other embodiment modes as appropriate.

[0249] (Embodiment 4) In this embodiment, a metal oxide (also referred to as an oxide semiconductor) which can be used for the OS transistor described in the above embodiment will be described.

[0250] The metal oxide preferably contains at least indium or zinc. In particular, it is preferable that the metal oxide contains indium and zinc. In addition to these, it is preferable that the metal oxide contains aluminum, gallium, yttrium, tin, etc. Furthermore, the metal oxide may contain one or more elements selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, etc.

[0251] Moreover, the metal oxide can be formed by a sputtering method, a chemical vapor deposition (CVD) method such as a metal organic chemical vapor deposition (MOCVD) method, or an atomic layer deposition (ALD) method.

[0252] <Classification of crystal structures> Examples of the crystal structure of an oxide semiconductor include amorphous (including completely amorphous), c-axis-aligned crystalline (CAAC), nanocrystalline (nc), cloud-aligned composite (CAC), single crystal, and polycrystal.

[0253] The crystal structure of the film or substrate can be evaluated using an X-ray diffraction (XRD) spectrum. For example, it can be evaluated using an XRD spectrum obtained by a GIXD (Grazing-Incidence XRD) measurement. The GIXD method is also called the thin film method or the Seemann-Bohlin method.

[0254] For example, in the case of a quartz glass substrate, the peak shape of the XRD spectrum is almost symmetric. On the other hand, in the case of an IGZO film having a crystalline structure, the peak shape of the XRD spectrum is asymmetric. The asymmetric peak shape of the XRD spectrum clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetric, the film or substrate cannot be said to be in an amorphous state.

[0255] The crystal structure of a film or substrate can be evaluated by a diffraction pattern (also called a nanobeam electron diffraction pattern) observed by nanobeam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, and it can be confirmed that the quartz glass is in an amorphous state. In addition, a spot-like pattern is observed in the diffraction pattern of an IGZO film formed at room temperature, rather than a halo. For this reason, it is presumed that an IGZO film formed at room temperature is in an intermediate state that is neither crystalline nor amorphous, and therefore it cannot be concluded that it is in an amorphous state.

[0256] <<Structure of oxide semiconductor>> Note that oxide semiconductors may be classified differently from the above when focusing on their structures. For example, oxide semiconductors are classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0257] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0258] [CAAC-OS] CAAC-OS is an oxide semiconductor having a plurality of crystalline regions, each of which has a c-axis aligned in a specific direction. The specific direction is the thickness direction of the CAAC-OS film, the normal direction of the surface on which the CAAC-OS film is formed, or the normal direction of the surface of the CAAC-OS film. The crystalline region is a region having periodic atomic arrangement. If the atomic arrangement is considered as a lattice arrangement, the crystalline region is also a region with a uniform lattice arrangement. CAAC-OS has a region in which a plurality of crystalline regions are connected in the ab-plane direction, and the region may have distortion. The distortion refers to a portion in which the direction of the lattice arrangement changes between a region with a uniform lattice arrangement and another region with a uniform lattice arrangement in the region in which the plurality of crystalline regions are connected. In other words, CAAC-OS is an oxide semiconductor having a c-axis aligned and no clear orientation in the ab-plane direction.

[0259] Each of the multiple crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of one minute crystal, the maximum diameter of the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of the crystalline region may be about several tens of nm.

[0260] In addition, in an In-M-Zn oxide (wherein element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), the CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium (In) and oxygen (hereinafter, In layer) and a layer containing element M, zinc (Zn), and oxygen (hereinafter, (M, Zn) layer) are stacked. Note that indium and element M are mutually substituted. Thus, the (M, Zn) layer may contain indium. Also, the In layer may contain element M. Note that the In layer may contain Zn. The layered structure is observed as a lattice image in a high-resolution transmission electron microscope (TEM) image, for example.

[0261] When the CAAC-OS film is subjected to structural analysis using, for example, an XRD device, a peak indicating c-axis orientation is detected at or near 2θ=31° in out-of-plane XRD measurement using θ / 2θ scan. Note that the position of the peak indicating c-axis orientation (2θ value) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0262] For example, a plurality of bright points (spots) are observed in the electron diffraction pattern of the CAAC-OS film, and the two spots are observed at positions symmetrical to each other with respect to the spot of the incident electron beam that has passed through the sample (also called the direct spot).

[0263] When the crystal region is observed from the specific direction, the lattice arrangement in the crystal region is based on a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be a non-regular hexagon. The above distortion may have a lattice arrangement such as a pentagon or heptagon. In addition, in the CAAC-OS, no clear grain boundary can be confirmed even in the vicinity of the distortion. That is, it is found that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is considered to be because the CAAC-OS can tolerate distortion due to the fact that the arrangement of oxygen atoms in the ab-plane direction is not dense and the bond distance between atoms changes due to the substitution of metal atoms.

[0264] A crystal structure in which clear grain boundaries are observed is called a polycrystal. The grain boundaries are likely to become recombination centers and capture carriers, causing a decrease in the on-current of a transistor and a decrease in field effect mobility. Therefore, CAAC-OS in which clear grain boundaries are not observed is one of the crystalline oxides having a crystal structure suitable for a semiconductor layer of a transistor. In order to form a CAAC-OS, a structure containing Zn is preferable. For example, In-Zn oxide and In-Ga-Zn oxide are suitable because they can suppress the occurrence of grain boundaries more than In oxide.

[0265] The CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to crystal grain boundaries. In addition, since the crystallinity of an oxide semiconductor can be decreased by the inclusion of impurities or the generation of defects, the CAAC-OS can be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Therefore, the physical properties of an oxide semiconductor having the CAAC-OS are stable. Therefore, an oxide semiconductor having the CAAC-OS is resistant to heat and has high reliability. In addition, the CAAC-OS is stable against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, the use of the CAAC-OS in an OS transistor can increase the degree of freedom in the manufacturing process.

[0266] [nc-OS] The nc-OS has periodic atomic arrangement in a minute region (for example, a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has minute crystals. Note that the size of the minute crystals is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore the minute crystals are also called nanocrystals. In addition, the nc-OS does not show regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is seen in the entire film. Therefore, depending on the analysis method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor. For example, when a structure analysis is performed on an nc-OS film using an XRD device, no peak indicating crystallinity is detected in out-of-plane XRD measurement using θ / 2θ scan. In addition, when an nc-OS film is subjected to electron diffraction (also called selected area electron diffraction) using an electron beam with a probe diameter larger than that of nanocrystals (for example, 50 nm or more), a diffraction pattern like a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter (e.g., 1 nm to 30 nm) that is close to the size of a nanocrystal or smaller than the nanocrystal, an electron diffraction pattern in which multiple spots are observed within a ring-shaped region centered on the direct spot may be obtained.

[0267] [a-like OS] The a-like OS is an oxide semiconductor having a structure between the nc-OS and the amorphous oxide semiconductor. The a-like OS has a void or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS. Moreover, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and CAAC-OS.

[0268] <<Oxide semiconductor structure>> Next, the above-mentioned CAC-OS will be described in detail, with reference to its material composition.

[0269] [CAC-OS] CAC-OS is, for example, a material configuration in which elements constituting a metal oxide are unevenly distributed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof. In the following, a state in which one or more metal elements are unevenly distributed in a metal oxide and the regions having the metal elements are mixed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof, is also referred to as a mosaic or patch state.

[0270] Furthermore, CAC-OS is a composite metal oxide in which the material is separated into a first region and a second region, forming a mosaic structure, and the first region is distributed throughout the film (hereinafter, also referred to as a cloud structure). In other words, CAC-OS is a composite metal oxide in which the first region and the second region are mixed together.

[0271] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In-Ga-Zn oxide are represented as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in the In-Ga-Zn oxide, the first region is a region where [In] is larger than [In] in the composition of the CAC-OS. Also, the second region is a region where [Ga] is larger than [Ga] in the composition of the CAC-OS. Alternatively, for example, the first region is a region where [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. Also, the second region is a region where [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

[0272] Specifically, the first region is a region mainly composed of indium oxide, indium zinc oxide, etc., and the second region is a region mainly composed of gallium oxide, gallium zinc oxide, etc. In other words, the first region can be rephrased as a region mainly composed of In, and the second region can be rephrased as a region mainly composed of Ga.

[0273] In addition, there are cases where a clear boundary between the first region and the second region cannot be observed.

[0274] In addition, the CAC-OS in In-Ga-Zn oxide refers to a structure in which some regions mainly composed of Ga and some regions mainly composed of In are arranged randomly in a mosaic pattern in a material structure containing In, Ga, Zn, and O. Therefore, it is presumed that the CAC-OS has a structure in which metal elements are distributed non-uniformly.

[0275] CAC-OS can be formed, for example, by a sputtering method under conditions where the substrate is not heated. When CAC-OS is formed by a sputtering method, any one or more selected from an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as the film formation gas. The lower the flow rate ratio of oxygen gas to the total flow rate of film formation gas during film formation, the more preferable it is. For example, the flow rate ratio of oxygen gas to the total flow rate of film formation gas during film formation is preferably 0% or more and less than 30%, and more preferably 0% or more and 10% or less.

[0276] Furthermore, for example, in the case of a CAC-OS of an In-Ga-Zn oxide, EDX mapping obtained using EDX (Energy Dispersive X-ray spectroscopy) can confirm that the CAC-OS has a structure in which a region mainly composed of In (first region) and a region mainly composed of Ga (second region) are unevenly distributed and mixed.

[0277] Here, the first region is a region with higher conductivity than the second region. In other words, the first region exhibits conductivity as a metal oxide when carriers flow through the first region. Therefore, the first region is distributed in a cloud-like shape in the metal oxide, thereby realizing a high field-effect mobility (μ).

[0278] On the other hand, the second region has higher insulating properties than the first region. That is, the second region is distributed in the metal oxide, so that leakage current can be suppressed.

[0279] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region act in a complementary manner, giving the CAC-OS a switching function (On / Off function). In other words, CAC-OS has a conductive function in part of the material and an insulating function in part of the material, and the material as a whole functions as a semiconductor. By separating the conductive function from the insulating function, it is possible to maximize both functions. Therefore, by using CAC-OS in a transistor, it is possible to achieve a high on-current (I on ), high field effect mobility (μ), and good switching operation can be achieved.

[0280] In addition, a transistor using CAC-OS has high reliability, making it ideal for various semiconductor devices such as display devices.

[0281] Oxide semiconductors have a variety of structures and each structure has different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, a CAC-OS, an nc-OS, and a CAAC-OS.

[0282] <Transistor Having Oxide Semiconductor> Next, the case where the oxide semiconductor is used for a transistor will be described.

[0283] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0284] For the transistor, an oxide semiconductor having a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 Less than or equal to 1×10 15 cm -3 Less than 1×10, more preferably 13 cm -3Less than or equal to 1×10 11 cm -3 Less than 1×10, more preferably 10 cm -3 Less than 1 x 10 -9 cm -3 The above is the case. Note that in order to reduce the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification and the like, an oxide semiconductor having a low impurity concentration and a low density of defect states is referred to as a high-purity intrinsic or substantially high-purity intrinsic oxide semiconductor. Note that an oxide semiconductor having a low carrier concentration may be referred to as a high-purity intrinsic or substantially high-purity intrinsic oxide semiconductor.

[0285] In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore the density of trap states might also be low.

[0286] In addition, charges trapped in the trap states of an oxide semiconductor take a long time to disappear and may behave as if they are fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0287] Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. In order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in a nearby film. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, and the like.

[0288] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0289] When an oxide semiconductor contains silicon or carbon, which is one of the group 14 elements, defect levels are formed in the oxide semiconductor. For this reason, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are set to 2×10 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0290] In addition, when an oxide semiconductor contains an alkali metal or an alkaline earth metal, defect levels are formed and carriers are generated in some cases. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal is likely to have normally-on characteristics. For this reason, when the concentration of an alkali metal or an alkaline earth metal in an oxide semiconductor obtained by SIMS is 1×10 18 atoms / cm 3 Less than or equal to 2 x 10 16 atoms / cm 3 To the following:

[0291] Furthermore, when nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor is likely to have normally-on characteristics. Alternatively, when nitrogen is contained in an oxide semiconductor, trap states may be formed. As a result, the electrical characteristics of the transistor may become unstable. For this reason, the nitrogen concentration in an oxide semiconductor obtained by SIMS is set to 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than or equal to 1×10 18 atoms / cm 3 Less than 5×10, more preferably 17 atoms / cm 3 To the following:

[0292] Furthermore, hydrogen contained in an oxide semiconductor reacts with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. When hydrogen enters the oxygen vacancy, electrons serving as carriers may be generated. In addition, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons serving as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. For this reason, it is preferable to reduce hydrogen in the oxide semiconductor as much as possible. Specifically, when the hydrogen concentration in an oxide semiconductor measured by SIMS is 1×10 20 atoms / cm 3 Less than 1 x 10 19 atoms / cm 3 less than 5×10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 Make it less than.

[0293] When an oxide semiconductor in which impurities are sufficiently reduced is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0294] This embodiment mode can be combined with other embodiment modes as appropriate.

[0295] (Embodiment 5) In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS.

[0296] The electronic devices of this embodiment include the display device of one embodiment of the present invention in a display portion. The display device of one embodiment of the present invention can easily have high definition and high resolution. Therefore, the display device of one embodiment of the present invention can be used in the display portion of various electronic devices.

[0297] Examples of electronic devices include electronic devices with relatively large screens, such as television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and audio playback devices.

[0298] In particular, the display device of one embodiment of the present invention can be suitably used in electronic devices having a relatively small display area because it can increase the resolution. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), and head-mounted wearable devices such as VR devices such as head-mounted displays, AR devices such as glasses-type devices, and MR devices.

[0299] The display device of one embodiment of the present invention preferably has an extremely high resolution such as HD (1280×720 pixels), FHD (1920×1080 pixels), WQHD (2560×1440 pixels), WQXGA (2560×1600 pixels), 4K (3840×2160 pixels), or 8K (7680×4320 pixels). In particular, a resolution of 4K, 8K, or more is preferable. The pixel density (definition) of the display device of one embodiment of the present invention is preferably 100 ppi or more, more preferably 300 ppi or more, more preferably 500 ppi or more, more preferably 1000 ppi or more, more preferably 2000 ppi or more, more preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 7000 ppi or more. By using a display device having either or both of high resolution and high definition, it is possible to further improve the sense of realism and depth in electronic devices for personal use such as portable or home use. In addition, there is no particular limitation on the screen ratio (aspect ratio) of the display device of one embodiment of the present invention. For example, the display device can support various screen ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0300] The electronic device of this embodiment may have a sensor (including a function to measure force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0301] The electronic device of the present embodiment can have various functions, such as a function of displaying various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function of displaying a calendar, date, time, etc., a function of executing various software (programs), a wireless communication function, a function of reading out a program or data recorded on a recording medium, etc.

[0302] An example of a wearable device that can be worn on the head will be described with reference to Figs. 13A, 13B, 14A, and 14B. These wearable devices have one or both of a function to display AR content and a function to display VR content. These wearable devices may also have a function to display SR or MR content in addition to AR and VR. When an electronic device has a function to display content such as AR, VR, SR, and MR, it is possible to enhance the user's sense of immersion.

[0303] Electronic device 700A shown in FIG. 13A and electronic device 700B shown in FIG. 13B each have a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0304] The display device of one embodiment of the present invention can be applied to the display panel 751. Thus, the electronic device can provide an extremely high-definition display.

[0305] Each of the electronic devices 700A and 700B can project an image displayed on the display panel 751 onto a display area 756 of the optical member 753. Since the optical member 753 is translucent, the user can see the image displayed in the display area superimposed on a transmitted image visually recognized through the optical member 753. Therefore, each of the electronic devices 700A and 700B is an electronic device capable of AR display.

[0306] The electronic device 700A and the electronic device 700B may be provided with a camera capable of capturing an image of the front as an imaging unit. In addition, the electronic device 700A and the electronic device 700B may each be provided with an acceleration sensor such as a gyro sensor, thereby detecting the orientation of the user's head and displaying an image corresponding to the orientation in the display area 756.

[0307] The communication unit has a wireless communication device and can supply a video signal, etc., by the wireless communication device. Note that instead of or in addition to the wireless communication device, a connector to which a cable through which a video signal and a power supply potential can be connected may be provided.

[0308] Furthermore, the electronic device 700A and the electronic device 700B are provided with a battery, which can be charged wirelessly and / or wired.

[0309] The housing 721 may be provided with a touch sensor module. The touch sensor module has a function of detecting that the outer surface of the housing 721 is touched. The touch sensor module detects a tap operation or a slide operation by the user, and can execute various processes. For example, a tap operation can execute a process such as pausing or resuming a video, and a slide operation can execute a process such as fast forwarding or rewinding. In addition, by providing a touch sensor module in each of the two housings 721, the range of operations can be expanded.

[0310] As the touch sensor module, various touch sensors can be applied. For example, various types of sensors can be adopted, such as a capacitance type, a resistive film type, an infrared type, an electromagnetic induction type, a surface acoustic wave type, an optical type, etc. In particular, it is preferable to apply a capacitance type or an optical type sensor to the touch sensor module.

[0311] When an optical touch sensor is used, a photoelectric conversion device (also called a photoelectric conversion element) can be used as a light receiving device (also called a light receiving element). An active layer of the photoelectric conversion device can be made of either or both of an inorganic semiconductor and an organic semiconductor.

[0312] Electronic device 800A shown in FIG. 14A and electronic device 800B shown in FIG. 14B each have a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0313] The display device of one embodiment of the present invention can be applied to the display portion 820. Therefore, an electronic device capable of displaying images with extremely high definition can be provided, which allows a user to feel a high sense of immersion.

[0314] Display unit 820 is provided inside housing 821 at a position that can be viewed through lens 832. Also, by displaying different images on the pair of display units 820, it is possible to perform three-dimensional display using parallax.

[0315] The electronic device 800A and the electronic device 800B can each be said to be electronic devices for VR. A user wearing the electronic device 800A or the electronic device 800B can view an image displayed on the display unit 820 through the lens 832.

[0316] It is preferable that electronic device 800A and electronic device 800B each have a mechanism capable of adjusting the left-right positions of lens 832 and display unit 820 so that they are optimally positioned according to the position of the user's eyes. It is also preferable that electronic device 800A and electronic device 800B each have a mechanism for adjusting the focus by changing the distance between lens 832 and display unit 820.

[0317] The mounting unit 823 allows the user to mount the electronic device 800A or the electronic device 800B on the head. Note that, in Fig. 14A and other figures, the mounting unit 823 is shaped like the temples of glasses (also called joints or temples), but is not limited thereto. The mounting unit 823 may be shaped like a helmet or band, for example, as long as it can be worn by the user.

[0318] The imaging unit 825 has a function of acquiring external information. Data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used for the imaging unit 825. In addition, multiple cameras may be provided so as to be compatible with multiple angles of view, such as telephoto and wide angle.

[0319] Although an example having the imaging unit 825 is shown here, a distance measuring sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object may be provided. That is, the imaging unit 825 is one aspect of the detection unit. As the detection unit, for example, an image sensor or a distance image sensor such as a LIDAR (Light Detection and Ranging) can be used. By using an image obtained by the camera and an image obtained by the distance image sensor, more information can be obtained, enabling more accurate gesture operation.

[0320] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone. For example, a configuration having the vibration mechanism can be applied to one or more of the display unit 820, the housing 821, and the wearing unit 823. This makes it possible to enjoy video and audio by simply wearing the electronic device 800A without requiring a separate audio device such as headphones, earphones, or speakers.

[0321] The electronic device 800A and the electronic device 800B may each have an input terminal. The input terminal can be connected to a cable for supplying a video signal from a video output device or the like and power for charging a battery provided in the electronic device.

[0322] The electronic device of one embodiment of the present invention may have a function of wireless communication with the earphone 750. The earphone 750 has a communication unit (not shown) and has a wireless communication function. The earphone 750 can receive information (e.g., audio data) from the electronic device through the wireless communication function. For example, the electronic device 700A shown in FIG. 13A has a function of transmitting information to the earphone 750 through the wireless communication function. Furthermore, for example, the electronic device 800A shown in FIG. 14A has a function of transmitting information to the earphone 750 through the wireless communication function.

[0323] The electronic device may also have an earphone unit. Electronic device 700B shown in Fig. 13B has earphone unit 727. For example, earphone unit 727 and the control unit may be configured to be connected to each other by wire. A part of the wiring connecting earphone unit 727 and the control unit may be disposed inside housing 721 or wearing unit 723.

[0324] Similarly, electronic device 800B shown in Fig. 14B has earphone unit 827. For example, earphone unit 827 and control unit 824 can be configured to be connected to each other by wire. A part of the wiring connecting earphone unit 827 and control unit 824 may be disposed inside housing 821 or wearing unit 823. In addition, earphone unit 827 and wearing unit 823 may have a magnet. This allows earphone unit 827 to be fixed to wearing unit 823 by magnetic force, which is preferable as it makes storage easier.

[0325] The electronic device may have an audio output terminal to which earphones or headphones can be connected. The electronic device may have one or both of an audio input terminal and an audio input mechanism. For example, a sound collector such as a microphone can be used as the audio input mechanism. The electronic device may have a function as a so-called headset by having the audio input mechanism.

[0326] As described above, as electronic devices according to one embodiment of the present invention, both glasses-type devices (such as the electronic device 700A and the electronic device 700B) and goggles-type devices (such as the electronic device 800A and the electronic device 800B) are suitable.

[0327] Furthermore, the electronic device according to one embodiment of the present invention can transmit information to the earphones in a wired or wireless manner.

[0328] Electronic device 6500 shown in FIG. 15A is a portable information terminal that can be used as a smartphone.

[0329] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508. The display portion 6502 has a touch panel function.

[0330] The display device of one embodiment of the present invention can be applied to the display portion 6502.

[0331] FIG. 15B is a schematic cross-sectional view including the end of the housing 6501 on the microphone 6506 side.

[0332] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0333] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by an adhesive layer (not shown).

[0334] In an area outside the display unit 6502, a part of the display panel 6511 is folded back, and the folded back part is connected to an FPC 6515. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0335] The flexible display of one embodiment of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted thereon while suppressing the thickness of the electronic device. In addition, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0336] 16A shows an example of a television device. In a television device 7100, a display unit 7000 is incorporated in a housing 7101. Here, the housing 7101 is supported by a stand 7103.

[0337] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0338] 16A can be operated by an operation switch provided on the housing 7101 and a separate remote control 7111. Alternatively, a touch sensor may be provided on the display unit 7000, and the television unit 7100 may be operated by touching the display unit 7000 with a finger or the like. The remote control 7111 may have a display unit that displays information output from the remote control 7111. The channel and volume can be operated by the operation keys or touch panel provided on the remote control 7111, and the video displayed on the display unit 7000 can be operated.

[0339] The television device 7100 includes a receiver and a modem. The receiver can receive general television broadcasts. By connecting to a wired or wireless communication network via the modem, one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers) information communication can be performed.

[0340] 16B shows an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. A display unit 7000 is incorporated in the housing 7211.

[0341] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0342] 16C and 16D show an example of digital signage.

[0343] 16C includes a housing 7301, a display unit 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, an operation key (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0344] 16D shows a digital signage 7400 attached to a cylindrical pole 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pole 7401.

[0345] 16C and 16D, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0346] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it catches people's attention, which can increase the advertising effect of, for example, advertisements.

[0347] Applying a touch panel to the display unit 7000 is preferable because it not only displays images or videos on the display unit 7000 but also allows the user to intuitively operate it. Furthermore, when used for providing information such as route information or traffic information, the intuitive operation can improve usability.

[0348] 16C and 16D, it is preferable that the digital signage 7300 or the digital signage 7400 can be linked via wireless communication with an information terminal 7311 or an information terminal 7411 such as a smartphone carried by a user. For example, advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or the information terminal 7411. Furthermore, the display on the display unit 7000 can be switched by operating the information terminal 7311 or the information terminal 7411.

[0349] In addition, a game can be executed on the digital signage 7300 or the digital signage 7400 using the screen of the information terminal 7311 or the information terminal 7411 as an operation means (controller). This allows an unspecified number of users to participate in and enjoy the game at the same time.

[0350] The electronic device shown in Figures 17A to 17F has a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including a function to measure force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone 9008, etc.

[0351] 17A to 17F, the display device of one embodiment of the present invention can be applied to the display portion 9001.

[0352] The electronic device shown in Fig. 17A to Fig. 17F has various functions. For example, it can have a function of displaying various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function of displaying a calendar, date or time, a function of controlling processing by various software (programs), a wireless communication function, a function of reading and processing a program or data recorded on a recording medium, etc. The functions of the electronic device are not limited to these, and it can have various functions. The electronic device may have multiple display units. In addition, the electronic device may have a camera or the like to capture still images or videos and store them on a recording medium (external or built-in to the camera), a function of displaying the captured images on the display unit, etc.

[0353] The electronic device shown in FIGS. 17A to 17F will be described in detail below.

[0354] FIG. 17A is a perspective view showing a mobile information terminal 9101. The mobile information terminal 9101 can be used as, for example, a smartphone. The mobile information terminal 9101 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, and the like. The mobile information terminal 9101 can display text and image information on a plurality of surfaces. FIG. 17A shows an example in which three icons 9050 are displayed. Information 9051 shown in a dashed rectangle can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notifications of incoming e-mail, SNS, and phone calls, titles of e-mail or SNS, sender names, date and time, time, remaining battery power, and radio wave intensity. Alternatively, the icon 9050 and the like may be displayed at the position where the information 9051 is displayed.

[0355] 17B is a perspective view showing a mobile information terminal 9102. The mobile information terminal 9102 has a function of displaying information on three or more sides of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, a user can check information 9053 displayed in a position that can be observed from above the mobile information terminal 9102 while the mobile information terminal 9102 is stored in a breast pocket of clothes. The user can check the display without taking the mobile information terminal 9102 out of the pocket and decide, for example, whether or not to answer a call.

[0356] FIG. 17C is a perspective view showing a wristwatch-type mobile information terminal 9200. The mobile information terminal 9200 can be used as, for example, a smart watch (registered trademark). The display surface of the display unit 9001 is curved, and display can be performed along the curved display surface. The mobile information terminal 9200 can also perform hands-free conversation by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and charging with another information terminal through a connection terminal 9006. The charging operation may be performed by wireless power supply.

[0357] 17D to 17F are perspective views showing a foldable mobile information terminal 9201. FIG. 17D is a perspective view of the mobile information terminal 9201 in an unfolded state, FIG. 17F is a perspective view of the mobile information terminal 9201 in a folded state, and FIG. 17E is a perspective view of a state in the middle of changing from one of FIG. 17D and FIG. 17F to the other. The mobile information terminal 9201 has excellent portability in a folded state, and has excellent viewability of the display due to a seamless wide display area in an unfolded state. A display unit 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by a hinge 9055. For example, the display unit 9001 can be bent with a curvature radius of 0.1 mm or more and 150 mm or less.

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

[0359] 100A: display device, 100B: display device, 100C: display device, 100: display device, 101: layer including transistor, 110a: subpixel, 110b: subpixel, 110c: subpixel, 110: pixel, 111a: pixel electrode, 111b: pixel electrode, 111c: pixel electrode, 111: conductive film, 113a: first layer, 113b: second layer, 113c: third layer, 114: electron injection layer, 115: common electrode, 116: fourth electron transport layer, 118A: first sacrificial layer, 118a: first sacrificial layer, 118B: second sacrificial layer, 118b: second sacrificial layer, 118C: third sacrificial layer, 118c: third sacrificial layer, 119: resin layer, 120: substrate, 123: conductive layer, 130a: light emitting device, 130b: light emitting device, 130c: light emitting device, 131: protective layer, 132: protective layer, 133: gap, 134: insulator, 140: connection portion, 181A: first hole injection layer, 181a: first hole injection layer, 181B: second hole injection layer, 181b: second hole injection layer, 181C: third hole injection layer, 181c: third hole injection layer, 182A: first hole transport layer, 182a: first hole transport layer, 182B: second hole transport layer, 182b: second hole transport layer , 182C: third hole transport layer, 182c: third hole transport layer, 183A: first light emitting layer, 183a: first light emitting layer, 183B: second light emitting layer, 183b: second light emitting layer, 183C: third light emitting layer, 183c: third light emitting layer, 184A: first electron transport layer, 184a: first electron transport layer, 184B: second electron transport layer, 184b: second electron transport layer, 184C: third electron transport layer, 184c: third electron transport layer, 190a: resist mask, 190b: resist mask, 190c: resist mask, 240: capacitance, 241: conductive layer, 243: insulating layer, 2 45: conductive layer, 251: conductive layer, 252: conductive layer, 254: insulating layer, 255: insulating layer, 256: plug, 261: insulating layer, 262: insulating layer, 263: insulating layer, 264: insulating layer, 265: insulating layer, 271: plug, 274a: conductive layer, 274b: conductive layer, 274: plug, 280: display module, 281: display section, 282: circuit section, 283a: pixel circuit, 283: pixel circuit section, 284a: pixel, 284: pixel section, 285: terminal section, 286: wiring section, 290: FPC, 291: substrate, 292: substrate, 301: substrate, 310: transistor, 311: conductive layer,312: low resistance region, 313: insulating layer, 314: insulating layer, 315: element isolation layer, 320: transistor, 321: semiconductor layer, 323: insulating layer, 324: conductive layer, 325: conductive layer, 326: insulating layer, 327: conductive layer, 328: insulating layer, 329: insulating layer, 331: substrate, 332: insulating layer, 700A: electronic device, 700B: electronic device, 721: housing, 723: wearing part, 727: earphone part, 750: earphone, 751: display panel, 753: optical member, 756: display area, 757: frame, 758: nose pad, 772: electrode, 786a:E L layer, 786b: EL layer, 786: EL layer, 788: electrode, 800A: electronic device, 800B: electronic device, 820: display unit, 821: housing, 822: communication unit, 823: wearing unit, 824: control unit, 825: imaging unit, 827: earphone unit, 832: lens, 4411: light-emitting layer, 4412: light-emitting layer, 4413: light-emitting layer, 4420: layer, 4421: layer, 4422: layer, 4430: layer, 4431: layer, 4432: layer, 4440: intermediate layer, 6500: electronic device, 6501: housing, 6502: display unit, 6503: power button, 6504: button, 6505: Speaker, 6506: microphone, 6507: camera, 6508: light source, 6510: protective member, 6511: display panel, 6512: optical member, 6513: touch sensor panel, 6515: FPC, 6516: IC, 6517: printed circuit board, 6518: battery, 7000: display unit, 7100: television device, 7101: housing, 7103: stand, 7111: remote control device, 7200: notebook personal computer, 7211: housing, 7212: keyboard, 7213: pointing device, 7214: external connection port, 73 00: digital signage, 7301: housing, 7303: speaker, 7311: information terminal, 7400: digital signage, 7401: pillar, 7411: information terminal, 9000: housing, 9001: display, 9003: speaker, 9005: operation key, 9006: connection terminal, 9007: sensor, 9008: microphone, 9050: icon, 9051: information, 9052: information, 9053: information, 9054: information, 9055: hinge, 9101: portable information terminal, 9102: portable information terminal, 9200: portable information terminal, 9201: portable information terminal,

Claims

1. a first light emitting device and a second light emitting device; the first light-emitting device comprises a first pixel electrode, a first hole injection layer on the first pixel electrode, a first hole transport layer on the first hole injection layer, a first light-emitting layer on the first hole transport layer, a first electron transport layer on the first light-emitting layer, a second electron transport layer on the first electron transport layer, an electron injection layer on the second electron transport layer, and a common electrode on the electron injection layer; the second light-emitting device comprises a second pixel electrode, a second hole injection layer on the second pixel electrode, a second hole transport layer on the second hole injection layer, a second light-emitting layer on the second hole transport layer, a third electron transport layer on the second light-emitting layer, the second electron transport layer on the third electron transport layer, the electron injection layer on the second electron transport layer, and the common electrode on the electron injection layer; the first light-emitting device and the second light-emitting device have a function of emitting light of different colors; a second electron transport layer in contact with at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, a side surface of the first light-emitting layer, and a side surface of the second light-emitting layer.

2. In claim 1, The display device further comprises a protective layer on the common electrode.

3. In claim 1 or 2, the first light emitting device and the second light emitting device are disposed on an insulating layer; The insulating layer has a recess. The second electron transport layer is in contact with the recess.

4. In any one of claims 1 to 3, The display device further comprises a gap between the second electron transport layer and the electron injection layer.

5. In any one of claims 1 to 3, The display device further comprises an insulator between the second electron transport layer and the electron injection layer.

6. A display device according to any one of claims 1 to 5, A display module having at least one of a connector and an integrated circuit.

7. A display module according to claim 6; An electronic device having at least one of a housing, a battery, a camera, a speaker, and a microphone.

8. Forming an insulating layer; forming a conductive film on the insulating layer; forming a first hole injection layer on the conductive film; forming a first hole transport layer on the first hole injection layer; forming a first light-emitting layer on the first hole transport layer; forming a first electron transport layer on the first light emitting layer; forming a first sacrificial layer on the first electron transport layer; processing the first hole injection layer, the first hole transport layer, the first light emitting layer, the first electron transport layer, and the first sacrificial layer to expose a portion of the conductive film; forming a second hole injection layer on the first sacrificial layer and on the conductive film; forming a second hole transport layer on the second hole injection layer; forming a second light-emitting layer on the second hole transport layer; forming a second electron transport layer on the second light emitting layer; forming a second sacrificial layer on the second electron transport layer; processing the second hole injection layer, the second hole transport layer, the second light emitting layer, the second electron transport layer, and the second sacrificial layer to expose a portion of the conductive film; forming a first pixel electrode overlapping the first sacrificial layer and a second pixel electrode overlapping the second sacrificial layer by processing the conductive film using the first sacrificial layer and the second sacrificial layer as a hard mask; removing the first sacrificial layer and the second sacrificial layer; forming a third electron transport layer on the first electron transport layer and on the second electron transport layer; forming an electron injection layer on the third electron transport layer; A common electrode is formed on the electron injection layer.

9. In claim 8, A protective layer is formed on the common electrode.

10. In claim 8 or 9, the third electron transport layer is provided so as to cover at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, a side surface of the first light-emitting layer, and a side surface of the second light-emitting layer.

11. In any one of claims 8 to 10, The method for manufacturing a display device further comprises filling a recess in the third electron transport layer with an insulating material before forming the electron injection layer.

12. In any one of claims 8 to 11, The method for manufacturing a display device further comprises forming a recess in the insulating layer in the processing of the conductive film.

Images