Indication device

Abstract

This invention provides a high-definition display device and a method for manufacturing the same. [Solution] The display device includes a first insulating layer, a light-emitting element on the first insulating layer and a first conductive layer, a first layer on the first conductive layer, a second conductive layer on the first layer, a second insulating layer on the light-emitting element, on the second conductive layer and on the first insulating layer, and a third conductive layer on the second insulating layer. The light-emitting element includes a fourth conductive layer, a second layer on the fourth conductive layer, a third layer on the second layer, and a fifth conductive layer on the third layer. The third conductive layer has a region that contacts the second conductive layer through a first opening provided in the second insulating layer, and a region that contacts the fifth conductive layer through a second opening provided in the second insulating layer. The second layer contains a luminescent compound, the first conductive layer and the fourth conductive layer contain the same material, the first layer and the third layer contain the same material, and the second conductive layer and the fifth conductive layer contain the same material.

Description

Technical Field

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

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

Background Art

[0003] In recent years, higher definition of display panels has been demanded. As devices that require high-definition display panels, for example, devices for virtual reality (VR: Virtual Reality), augmented reality (AR: Augmented Reality), substitutional reality (SR: Substitutional Reality), or mixed reality (MR: Mixed Reality) have been actively developed in recent years.

[0004] In addition, typical display devices applicable to display panels include liquid crystal display devices, light-emitting devices having light-emitting elements such as organic EL (Electro Luminescence) elements and light-emitting diodes (LED: Light Emitting Diode), and electronic paper that performs display by an electrophoretic method or the like.

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

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

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

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

[0010] Furthermore, the description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not need to solve all of these problems. Other problems can be identified from the description in the specification, drawings, claims, etc. [Means for solving the problem]

[0011] One aspect of the present invention is a display device comprising a first insulating layer, a light-emitting element and a first conductive layer on the first insulating layer, a first layer on the first conductive layer, a second conductive layer on the first layer, and a third conductive layer on the light-emitting element and on the second conductive layer. The light-emitting element comprises a fourth conductive layer, a second layer on the fourth conductive layer, a third layer on the second layer, and a fifth conductive layer on the third layer, wherein the third conductive layer has a region in contact with the second conductive layer and a region in contact with the fifth conductive layer, the second layer contains a light-emitting compound, the first conductive layer and the fourth conductive layer contain the same material, the first layer and the third layer contain the same material, and the second conductive layer and the fifth conductive layer contain the same material.

[0012] Furthermore, one aspect of the present invention is a display device having a first insulating layer, a light-emitting element and a first conductive layer on the first insulating layer, a first layer on the first conductive layer, a second conductive layer on the first layer, a second insulating layer on the light-emitting element, on the second conductive layer, and on the first insulating layer, and a third conductive layer on the second insulating layer. The light-emitting element includes a fourth conductive layer, a second layer on the fourth conductive layer, a third layer on the second layer, and a fifth conductive layer on the third layer. The second insulating layer has regions in contact with the side surface of the fourth conductive layer, the side surface of the second layer, the side surface of the third layer, the side surface of the fifth conductive layer, and the upper surface of the fifth conductive layer. The second insulating layer has a first opening having a region overlapping with the second conductive layer and a second opening having a region overlapping with the fifth conductive layer. The third conductive layer has a region in contact with the second conductive layer through the first opening and a region in contact with the fifth conductive layer through the second opening. The second layer contains a light-emitting compound. The first conductive layer and the fourth conductive layer contain the same material. The first layer and the third layer contain the same material. The second conductive layer and the fifth conductive layer contain the same material.

[0013] In the above-described display device, the second insulating layer has a laminated structure of a third insulating layer and a fourth insulating layer on the third insulating layer, and the third insulating layer has a region in contact with the side surface of the fourth conductive layer, a region in contact with the side surface of the second layer, a region in contact with the side surface of the third layer, a region in contact with the side surface of the fifth conductive layer, and a region in contact with the upper surface of the fifth conductive layer, and preferably the third insulating layer contains aluminum and oxygen, and the fourth insulating layer contains silicon and nitrogen.

[0014] Furthermore, in the above-mentioned display device, it is preferable to have a void in the region between the third insulating layer and the fourth insulating layer, which does not overlap with the fifth conductive layer.

[0015] Furthermore, in the above-mentioned display device, the third layer preferably contains a substance with high electron injection properties. The third layer also preferably contains lithium fluoride.

[0016] Alternatively, in the above-mentioned display device, the third layer preferably comprises a compound having an electron-deficient heteroaromatic ring and silver.

[0017] Another aspect of the present invention involves forming a first conductive film on a first insulating layer, forming a first film containing a luminescent compound on the first conductive film, forming a first sacrificial layer on the first film, forming a first resist mask on the first sacrificial layer, and forming a second sacrificial layer from the first sacrificial layer by removing the first sacrificial layer and the first film that are not covered by the first resist mask, and forming a second film from the first film, removing the second sacrificial layer, and forming a third film on the second film. This is a method for manufacturing a display device, comprising: forming a second conductive film on a film; forming a second resist mask on the second conductive film; and removing the second conductive film, third film, second film, and first conductive film that are not covered by the second resist mask, thereby forming a fifth conductive layer and a second conductive layer from the second conductive film, forming a third layer and a first layer from the third film, forming a second layer from the second film, and forming a fourth conductive layer and a first conductive layer from the first conductive film.

[0018] Another aspect of the present invention involves forming a first conductive film on a first insulating layer, forming a first film containing a luminescent compound on the first conductive film, forming a first sacrificial layer on the first film, forming a first resist mask on the first sacrificial layer, and forming a second sacrificial layer from the first sacrificial layer by removing the first sacrificial layer and the first film that are not covered by the first resist mask, and forming a second film from the first film, removing the second sacrificial layer, and forming a third film on the second film using a metal mask, and the third This is a method for manufacturing a display device, comprising: forming a second conductive film on a film and on a first conductive film; forming a second resist mask on the second conductive film; and removing the second conductive film, third film, second film, and first conductive film that are not covered by the second resist mask, thereby forming a fifth conductive layer and a second conductive layer from the second conductive film, forming a third layer from the third film, forming a second layer from the second film, and forming a fourth conductive layer and a first conductive layer in contact with the second conductive layer from the first conductive film.

[0019] In the above method for manufacturing the display device, it is preferable to form a fifth conductive layer and a second conductive layer, a third layer and a first layer, a second layer, and a fourth conductive layer and a first conductive layer, then form a second insulating layer on the second conductive layer, on the fifth conductive layer, and on the first insulating layer, and form a first opening in the second insulating layer located in a region overlapping with the second conductive layer and a second opening located in a region overlapping with the fifth conductive layer, and then form a third conductive layer so as to be in contact with the second conductive layer through the first opening and in contact with the fifth conductive layer through the second opening.

[0020] In the method for manufacturing the above-described display device, it is preferable that the second insulating layer has a laminated structure of a third insulating layer and a fourth insulating layer on the third insulating layer, the third insulating layer is formed by the ALD method, and the fourth insulating layer is formed by the sputtering method.

[0021] Furthermore, in the method for manufacturing the above-mentioned display device, it is preferable that the second insulating layer has a laminated structure of a third insulating layer, a fourth insulating layer on the third insulating layer, and a fifth insulating layer on the fourth insulating layer, the third insulating layer and the fifth insulating layer are formed by the ALD method, and the fourth insulating layer is formed by the sputtering method.

[0022] Furthermore, in the method for manufacturing the above-described display device, the third film preferably contains a substance with high electron injection properties. The third film also preferably contains lithium fluoride.

[0023] Alternatively, in the method for manufacturing the above-mentioned display device, the third film preferably comprises a compound having an electron-deficient heteroaromatic ring and silver. [Effects of the Invention]

[0024] According to one aspect of the present invention, it is possible to provide an extremely high-definition display device, or a display device that achieves high color reproducibility, or a high-brightness display device, or a highly reliable display device, or a method for manufacturing the above-mentioned display device.

[0025] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description in the specification, drawings, claims, etc. [Brief explanation of the drawing]

[0026] [Figure 1] Figures 1A to 1C show examples of the configuration of a display device. [Figure 2] Figures 2A to 2C show examples of display device configurations. [Figure 3] Figures 3A to 3D show examples of display device configurations. [Figure 4] Figures 4A1 to 4C2 illustrate examples of methods for manufacturing a display device. [Figure 5] Figures 5A1 to 5D2 illustrate examples of methods for manufacturing a display device. [Figure 6] Figures 6A1 to 6C2 illustrate examples of methods for manufacturing a display device. [Figure 7] Figures 7A1 to 7D2 illustrate examples of methods for manufacturing a display device. [Figure 8] Figures 8A1 to 8B2 illustrate examples of methods for manufacturing a display device. [Figure 9] Figures 9A1 to 9C2 illustrate examples of methods for manufacturing a display device. [Figure 10] Figure 10 shows an example of a display device configuration. [Figure 11] Figure 11 shows an example of a display device configuration. [Figure 12] Figure 12 shows an example of a display device configuration. [Figure 13] Figure 13 shows an example of a display device configuration. [Figure 14] Figures 14A and 14B show examples of the configuration of a display module. [Figure 15]Figures 15A and 15B are circuit diagrams showing an example of a display device. [Figure 16] Figures 16A and 16C are circuit diagrams showing an example of a display device. Figure 16B is a timing chart showing an example of the display device's operation. [Figure 17] Figures 17A and 17B show examples of electronic device configurations. [Figure 18] Figures 18A and 18B show examples of electronic device configurations. [Figure 19] Figures 19A to 19F show examples of electronic devices. [Modes for carrying out the invention]

[0027] The embodiments will be described below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the embodiments can be implemented in many different ways, and their form and details can be modified in various ways without departing from the spirit and scope thereof. Accordingly, the present invention shall not be construed as being limited to the contents of the following embodiments.

[0028] In the configuration of the invention described below, the same reference numerals are used in common across different drawings for identical parts or parts having similar functions, and repeated explanations are omitted. Furthermore, when referring to similar functions, the hatch patterns are the same, and reference numerals may not be assigned.

[0029] In the figures described herein, the size of each component, the thickness of the layers, or the area may be exaggerated for clarity. Therefore, the scale is not necessarily limited to those figures.

[0030] Furthermore, ordinal numbers such as "the first," "the second," etc., used in this specification are added to avoid confusion of constituent elements and do not imply any numerical limitation.

[0031] Furthermore, in this specification, the terms "film" and "layer" are interchangeable. For example, the terms "conductive layer" or "insulating layer" may be interchangeable with the terms "conductive film" or "insulating film."

[0032] In this specification, the term "EL layer" refers to a layer (also called a light-emitting layer) provided between a pair of electrodes of a light-emitting element and containing at least a light-emitting substance, or a laminate including a light-emitting layer.

[0033] In this specification, a display panel, which is one form of a display device, has the function of displaying (outputting) images or the like on its display surface. Therefore, a display panel is one form of an output device.

[0034] Furthermore, in this specification, a display panel with a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) attached to the substrate, or a display panel with an IC mounted on the substrate using a COG (Chip On Glass) method, may be referred to as a display panel module, display module, or simply a display panel.

[0035] Furthermore, if upper and lower numerical limits are specified in this specification, configurations in which the upper and lower numerical limits can be freely combined are also disclosed.

[0036] (Embodiment 1) This embodiment describes an example of the configuration of a display device according to one aspect of the present invention, and an example of a method for manufacturing the display device.

[0037] A display device according to one aspect of the present invention comprises a light-emitting element (also called a light-emitting device) that emits light of different colors. The light-emitting element comprises a lower electrode, an upper electrode, and a layer containing a light-emitting compound (also called a light-emitting layer or EL layer) between them. As the light-emitting element, it is preferable to use an electroluminescent element such as an organic EL element or an inorganic EL element. In addition, a light-emitting diode (LED) may be used.

[0038] As EL elements, OLEDs (Organic Light Emitting Diodes) or QLEDs (Quantum-dot Light Emitting Diodes) can be used. Examples of light-emitting materials for EL elements include fluorescent materials, phosphorescent materials, inorganic compounds (such as quantum dot materials), and thermally activated delayed fluorescence (TADF) materials.

[0039] 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.

[0040] Examples of phosphorescent materials include organometallic complexes (especially iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton; organometallic complexes (especially iridium complexes) using phenylpyridine derivatives having electron-withdrawing groups as ligands; platinum complexes; and rare earth metal complexes.

[0041] The light-emitting layer may contain one or more types of organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). One or more of these organic compounds may be hole-transporting materials and / or electron-transporting materials. Alternatively, one or more of these organic compounds may be bipolar materials or TADF materials.

[0042] The light-emitting layer preferably comprises, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that readily forms an excitation complex. This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excitation complex to the light-emitting substance (phosphorescent material). By selecting a combination that forms an excitation complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the light-emitting substance, energy transfer becomes smoother, and light emission can be obtained efficiently. This configuration simultaneously achieves high efficiency, low-voltage operation, and a long lifespan for the light-emitting device.

[0043] As the luminescent material, materials exhibiting luminescent colors such as blue, purple, bluish-purple, green, yellowish-green, yellow, orange, and red may be used as appropriate. Materials emitting near-infrared light may also be used.

[0044] The light-emitting layer may contain one or more compounds (host material, assist material) in addition to the light-emitting substance (guest material). One or more materials with an energy gap larger than the energy gap of the light-emitting substance (guest material) can be selected and used as the host material and assist material. It is preferable to use a combination of compounds that form an excited complex as the host material and assist material. To efficiently form an excited complex, it is particularly preferable to combine a compound that readily accepts holes (hole transport material) with a compound that readily accepts electrons (electron transport material).

[0045] The light-emitting element can be made from either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds (such as quantum dot materials).

[0046] A display device according to one aspect of the present invention can create light-emitting elements of different colors with extremely high precision. Therefore, it is possible to realize a display device with higher resolution than conventional display devices. For example, it is preferable to have an extremely high-resolution display device in which pixels having one or more light-emitting elements have 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 are arranged with a resolution of 20000 ppi or less, or 30000 ppi or less.

[0047] In the following section, a more specific configuration example and manufacturing method example of a display device according to one aspect of the present invention will be described with reference to the drawings.

[0048] [Configuration Example 1] [Configuration Example 1-1] Figures 1A to 1C illustrate a display device according to one embodiment of the present invention. Figure 1A is a schematic top view of the display device 100, and Figures 1B and 1C are schematic cross-sectional views of the display device 100. Here, Figure 1B is a cross-sectional view of the area indicated by the dashed line X1-X2 in Figure 1A. Figure 1C is a cross-sectional view of the area indicated by the dashed line Y1-Y2 in Figure 1A. Note that some elements have been omitted from the top view of Figure 1A for clarity.

[0049] Furthermore, if the arrangement of the light-emitting elements is the stripe arrangement shown in Figure 1A, adjacent light-emitting elements of different colors are arranged in the X1-X2 direction, and adjacent light-emitting elements of the same color are arranged in the Y1-Y2 direction.

[0050] The display device 100 has an insulating layer 121, a light-emitting element 120R, a light-emitting element 120G, and a light-emitting element 120B. The light-emitting element 120R is a red-emitting element, the light-emitting element 120G is a green-emitting element, and the light-emitting element 120B is a blue-emitting element. In other words, the light-emitting element 120R and the light-emitting element 120G emit light of different colors. Also, the light-emitting element 120G and the light-emitting element 120B emit light of different colors. Also, the light-emitting element 120B and the light-emitting element 120R emit light of different colors. A structure in which each light-emitting element is color-coded (here, red (R), green (G), and blue (B)) is sometimes called an SBS (Side By Side) structure.

[0051] In this specification, a structure in which different light-emitting layers are created or painted for each color of light-emitting device (here, blue (B), green (G), and red (R)) may be referred to as an SBS structure. Also, in this specification, a light-emitting device capable of emitting white light may be referred to as a white light-emitting device. A white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0052] In the following, when explaining matters common to the light-emitting element 120R, light-emitting element 120G, and light-emitting element 120B, the symbols attached to the reference numerals may be omitted, and it may be referred to as light-emitting element 120. Similarly, the conductive layers 111R, 111G, and 111B, which will be described later, may be referred to as conductive layer 111. Similarly, the EL layers 115R, 115G, and 115B, which will be described later, may be referred to as EL layer 115. Similarly, the conductive layers 116R, 116G, and 116B, which will be described later, may be referred to as conductive layer 116. Conductive layers 111R, EL layer 115R, and conductive layer 116R are included in light-emitting element 120R. Similarly, conductive layer 111G, EL layer 115G, and conductive layer 116G are included in light-emitting element 120G, and conductive layer 111B, EL layer 115B, and conductive layer 116B are included in light-emitting element 120B.

[0053] Furthermore, the combination of colors of light emitted by the light-emitting element 120 is not limited to those described above; for example, cyan, magenta, and yellow may also be used. In addition, although the above example shows three colors, red (R), green (G), and blue (B), the number of colors of light emitted by the light-emitting element 120 included in the display device 100 may be two, four or more, or any number of colors.

[0054] The light-emitting element 120 has a conductive layer 111 and an EL layer 115 that function as a lower electrode, and a conductive layer 116 that function as an upper electrode. The conductive layer 116 is transparent and reflective to visible light. The EL layer 115 contains a light-emitting compound.

[0055] The light-emitting element 120 can be an electroluminescent element that emits light due to a current flowing through the EL layer 115 when a potential difference is applied between the conductive layer 111 and the conductive layer 116. In particular, it is preferable to apply an organic EL element using a light-emitting organic compound to the EL layer 115. Furthermore, it is preferable that the light-emitting element 120 is an element that emits monochromatic light having one peak in the visible light region in its emission spectrum. However, the light-emitting element 120 may also be an element that emits white light having two or more peaks in the visible light region in its emission spectrum.

[0056] A conductive layer 111 provided on each light-emitting element 120 is independently supplied with a potential that controls the amount of light emitted by the light-emitting element 120. The conductive layer 111 functions, for example, as a pixel electrode.

[0057] The EL layer 115 has a layer containing at least a luminescent compound. In addition, it may have a structure in which one or more selected from an electron injection layer, an electron transport layer, a charge generation layer, a hole transport layer, and a hole injection layer are laminated. The EL layer 115 can be formed by a liquid-phase method such as vapor deposition or inkjet printing.

[0058] The conductive layer 116 is formed to be transparent and reflective to visible light. For example, a thin metal film or alloy film that transmits visible light can be used. Alternatively, a light-transmitting conductive film (e.g., a metal oxide film) may be laminated onto such a film.

[0059] In the display device 100, the EL layer 115 and the conductive layer 116 are separated between adjacent light-emitting elements of different colors. This prevents current (also called leakage current) from flowing through the EL layer 115 between adjacent light-emitting elements of different colors. Therefore, the light emission caused by this leakage current can be suppressed, enabling a display with high contrast. Furthermore, even when increasing the resolution, a highly conductive material can be used for the EL layer 115, thus broadening the range of material choices and making it easier to improve efficiency, reduce power consumption, and improve reliability.

[0060] The EL layer 115 and the conductive layer 116 may be formed into island-like patterns by deposition using a shadow mask such as a metal mask, but it is particularly preferable to use a processing method that does not use a metal mask. This makes it possible to form extremely fine patterns, and thus improves the fineness and aperture ratio compared to the formation method using a metal mask. Typical processing methods that can be used for this purpose include photolithography. Other formation methods such as nanoimprint lithography and sandblasting can also be used.

[0061] In this specification, devices fabricated using a metal mask or an FMM (Fine Metal Mask, a high-resolution metal mask) may be referred to as MM (Metal Mask) structured devices. Furthermore, in this specification, devices fabricated without using a metal mask or an FMM may be referred to as MML (Metal Maskless) structured devices.

[0062] Based on the above, it is possible to realize an extremely high-resolution display device in which pixels having one or more light-emitting elements have 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 are arranged at a resolution of 20000 ppi or less, or 30000 ppi or less.

[0063] The display device 100 has a configuration in which the side surface of the conductive layer 111, the side surface of the EL layer 115, and the side surface of the conductive layer 116 are substantially aligned.

[0064] In this specification, "approximately matching sides" means that, when viewed from above, at least a portion of the contours of the upper and lower layers overlap. This includes cases where the upper and lower layers are processed with the same mask pattern, or partially with the same mask pattern. Furthermore, "approximately matching sides" also includes cases where the sides match. However, strictly speaking, the contours may not overlap, and the contour of the upper layer may be located inside the contour of the lower layer, or the contour of the upper layer may be located outside the contour of the lower layer; in these cases, it is also referred to as "approximately matching sides."

[0065] The insulating layer 121 is configured as a single layer or a laminated structure of two or more layers. For example, when the insulating layer 121 is a laminated structure of two layers, it is preferable to select an insulator for the layer on the conductive layer 111 side that functions as an etching stopper film when etching the conductive film that will become the conductive layer 111 to form the conductive layer 111. For example, when silicon oxide or silicon oxynitride is used for the layer on the substrate 101 side, silicon nitride, aluminum oxide, or hafnium oxide may be used for the layer on the conductive layer 111 side.

[0066] The display device 100 has a structure 132.

[0067] Structure 132 functions as wiring. Alternatively, structure 132 functions as a plug that electrically connects the conductive layer 139 and wiring (not shown) located below structure 132. Structure 132 has a conductive layer 133 on the insulating layer 121, a layer 134 on the conductive layer 133, and a conductive layer 135 on the layer 134. Structure 132 also has a configuration in which the sides of the conductive layer 133, the sides of the layer 134, and the sides of the conductive layer 135 are substantially coincide.

[0068] Conductive layer 133 and conductive layer 111 contain the same material. Similarly, conductive layer 135 and conductive layer 116 contain the same material. Furthermore, layer 134 contains the same material as EL layer 115.

[0069] Structure 132 needs to be conductive because it functions as a wiring or plug. On the other hand, layer 134 has a band gap because it contains the same material as the EL layer 115. Therefore, it is preferable that the thickness of layer 134 be thin. Preferably, the thickness of layer 134 is 0.5 nm or more and 10 nm or less, and more preferably 1 nm or more and 5 nm or less. With this configuration, conductive layer 133 and conductive layer 135 become conductive due to tunnel effect or dielectric breakdown. Thus, structure 132 can be conductive.

[0070] The display device 100 includes an insulating layer 117, an insulating layer 118 on the insulating layer 117, and a conductive layer 139.

[0071] The insulating layer 117 and the insulating layer 118 are provided with a first opening located in a region overlapping with the conductive layer 135 and a second opening located in a region overlapping with the conductive layer 116.

[0072] The insulating layer 117 is in contact with a portion of the upper surface of the insulating layer 121, a side surface of the light-emitting element 120, and a portion of the upper surface of the light-emitting element 120. In other words, the insulating layer 117 is in contact with a portion of the upper surface of the insulating layer 121, a side surface of the conductive layer 111, a side surface of the EL layer 115, a side surface of the conductive layer 116, and a portion of the upper surface of the conductive layer 116. The insulating layer 117 is also in contact with a side surface of the structure 132 and a portion of the upper surface of the structure 132. In other words, the insulating layer 117 is in contact with a side surface of the conductive layer 133, a side surface of layer 134, a side surface of the conductive layer 135, and a portion of the upper surface of the conductive layer 135.

[0073] It is preferable to use an inorganic material as the insulating layer 117. Examples of such inorganic materials include inorganic oxides, inorganic nitrides, or inorganic oxidnitrides. Furthermore, a film containing these materials can be used as a single layer or in a laminated structure. For example, an aluminum oxide film, a silicon oxide film, or a silicon nitride film can be used as the insulating layer 117. This can suppress the diffusion of impurities such as water.

[0074] Furthermore, it is preferable to use a film formed by atomic layer deposition (ALD) or the like for the insulating layer 117.

[0075] The ALD method utilizes the self-regulating properties of atoms to deposit atoms layer by layer, resulting in several advantages: ultra-thin film deposition is possible, deposition on structures with high aspect ratios is possible, film deposition with fewer defects such as pinholes is possible, film deposition with excellent coverage is possible, and film deposition is possible at low temperatures. Therefore, the insulating layer 117 can be deposited with good coverage on the sides of the conductive layer 116, the EL layer 115, and the conductive layer 111.

[0076] Based on the above, an aluminum oxide film formed by the ALD method can be suitably used as the insulating layer 117.

[0077] As the insulating layer 118, it is preferable to use, for example, an inorganic material, an organic material, or a composite material of an inorganic material and an organic material, and it is more preferable to use an inorganic material. Examples of such inorganic materials include inorganic oxides, inorganic nitrides, or inorganic oxidnitrides. Furthermore, a film containing these materials can be used as a single layer or in a laminated structure. For example, as the insulating layer 118, a silicon oxide film, a silicon nitride film, a silicon oxidnitride film, an aluminum oxide film, or an indium gallium zinc oxide film (also called an IGZO film) can be used. Furthermore, these films can be used as a single layer or in a laminated structure. Note that a silicon nitride film is a dense film and has excellent function in suppressing the diffusion of impurities such as water, so it can be suitably used as the insulating layer 118.

[0078] Alternatively, the insulating layer 118 may be made of, for example, polyester, polyolefin, polyamide, polyimide, polycarbonate, polysiloxane, or acrylic resin. Alternatively, the insulating layer 118 may be made of a laminated structure of the materials described above. Alternatively, the insulating layer 118 may be made of a composite material of the materials described above.

[0079] Alternatively, an organic material such as a reaction-curing adhesive, a photocuring adhesive, a thermosetting adhesive, or / or an anaerobic adhesive may be used as the insulating layer 118.

[0080] Although the display device 100 shows a configuration in which insulating layers 117 and 118 are provided, the present invention is not limited to this. For example, an insulating layer 117 may be provided, but insulating layer 118 may not be provided. Alternatively, an insulating layer 117 may not be provided, but insulating layer 118 may be provided. Alternatively, one or both of the insulating layers 117 and 118 may have a laminated structure.

[0081] The conductive layer 139 has a region that contacts the conductive layer 135 through a first opening provided in the insulating layer 117 and the insulating layer 118, and a region that contacts the conductive layer 116 through a second opening provided in the insulating layer 117 and the insulating layer 118. This configuration allows the conductive layer 116 and the conductive layer 135 to be electrically connected.

[0082] The conductive layer 139 can be formed using a conductive film that can be used for conductive layers 111, 116, etc.

[0083] With the above configuration, the EL layer of each light-emitting element 120 can be made separately for each light-emitting element of a different color, enabling color display with high color reproducibility and low power consumption. Furthermore, by adjusting the film thickness of the EL layer of the light-emitting element 120 to match the peak wavelength of the emission spectrum, a microcavity structure (micro-resonator structure) can be added, realizing a high-brightness display device. In addition, it becomes possible to arrange the light-emitting elements 120 at extremely high density. For example, a display device with a resolution exceeding 2000 ppi can be realized.

[0084] While a stripe arrangement is preferred for the light-emitting elements 120, other arrangements are also acceptable. For example, possible arrangements of the light-emitting elements 120 include a delta arrangement and a mosaic arrangement.

[0085] The display device 100 comprises the aforementioned insulating layer 121, light-emitting element 120R, light-emitting element 120G, and light-emitting element 120B on a substrate 101 equipped with a semiconductor circuit. The display device 100 also has a plug 131.

[0086] The substrate 101 can be a circuit board having transistors or wiring. If a passive matrix or segment method is applicable, an insulating substrate such as a glass substrate can be used as the substrate 101. Furthermore, the substrate 101 is a substrate on which semiconductor circuits function as circuits for driving each light-emitting element (also called pixel circuits), or as drive circuits for driving said pixel circuits. More specific examples of the substrate 101 configuration will be described later.

[0087] The substrate 101 and the conductive layer 111 of the light-emitting element 120 are electrically connected via a plug 131. The plug 131 is formed to be embedded in an opening provided in the insulating layer 121. The conductive layer 111 is provided in contact with the upper surface of the plug 131.

[0088] [Configuration Example 1-2] The display device 100 may have a gap between the insulating layer 117 and the insulating layer 118. Figure 2A is a schematic cross-sectional view of the display device 100 having a gap 137 between the insulating layer 117 and the insulating layer 118.

[0089] As shown in Figure 2A, the void 137 is located between the insulating layer 117 and the insulating layer 118, and in a region that does not overlap with the conductive layer 116.

[0090] The void 137 contains, for example, one or more of the following selected elements: air, nitrogen, oxygen, carbon dioxide, and Group 18 elements. The void 137 may also contain, for example, the gas used during the deposition of the insulating film that forms the insulating layer 118. For instance, when the insulating film that forms the insulating layer 118 is deposited by sputtering, the void 137 may contain Group 18 elements (typically helium, neon, argon, xenon, krypton, etc.). If the void 137 contains gas, the gas can be identified by gas chromatography or other methods. Alternatively, when the insulating film that forms the insulating layer 118 is deposited by sputtering, the insulating layer 118 may also contain the gas used during sputtering. In this case, when the insulating layer 118 is analyzed by energy-dispersive X-ray spectroscopy (EDX analysis), elements such as argon may be detected.

[0091] If the refractive index of the air gap 137 is lower than that of the EL layer 115, the light emitted by the EL layer 115 and incident on the interface between the EL layer 115 and the air gap 137 undergoes total internal reflection. This suppresses the incident light on adjacent light-emitting elements. Specifically, it is possible to suppress the incident light emitted by the EL layer 115R on the light-emitting element 120G or 120B. Similarly, it is possible to suppress the incident light emitted by the EL layer 115G on the light-emitting element 120R or 120B. Furthermore, it is possible to suppress the incident light emitted by the EL layer 115B on the light-emitting element 120R or 120G. As a result, mixing of light of different colors is suppressed, enabling the display device 100 to display high-quality images.

[0092] [Configuration Examples 1-3] The insulating layer 118 may have a laminated structure of insulating layer 118a and insulating layer 118b. Figure 2B is a schematic cross-sectional view of a display device 100 in which the insulating layer 118 has a laminated structure of insulating layer 118a and insulating layer 118b.

[0093] The insulating layer 118 has an insulating layer 118a on the insulating layer 117 and an insulating layer 118b on the insulating layer 118a.

[0094] The insulating layer 118a and the insulating layer 118b differ in material and / or film deposition method. For example, it is preferable to use a silicon nitride film deposited by sputtering as the insulating layer 118a and a silicon nitride film deposited by PEALD as the insulating layer 118b. This allows for the sealing of areas overlapping with pinholes or cracks in the film deposited by sputtering if pinholes or cracks are formed.

[0095] Furthermore, three or more layers of films made of different materials and / or formed by different methods may be laminated as the insulating layer 118.

[0096] Furthermore, as shown in Figure 2B, the insulating layer 121 may have recesses in areas that do not overlap with the conductive layer 111.

[0097] [Configuration Examples 1-4] The structure 132 may not have layer 134. Figure 2C is a schematic cross-sectional view of a display device 100 having a structure 132 composed of a conductive layer 133 and a conductive layer 135.

[0098] The structure 132 has a conductive layer 133 on the insulating layer 121 and a conductive layer 135 on the conductive layer 133. With this configuration, the structure 132 can be conductive regardless of the material used for the EL layer 115. Therefore, the structure 132 can function as wiring or a plug.

[0099] [About the components] [Light-emitting element] The light-emitting element that can be used in the light-emitting element 120 can be a self-emitting element, and this category includes elements whose brightness can be controlled by current or voltage. For example, LEDs, organic EL elements, inorganic EL elements, etc., can be used. In particular, the use of organic EL elements is preferred.

[0100] Light-emitting elements include top-emission, bottom-emission, and dual-emission types. The electrode that extracts light uses a conductive film that transmits visible light. The electrode that does not extract light uses a conductive film that reflects visible light.

[0101] In one aspect of the present invention, a top-emission or dual-emission type light-emitting element that emits light particularly on the side opposite to the surface to be formed can be suitably used.

[0102] The EL layer 115 has at least an emissive layer. The EL layer 115 may further have layers other than the emissive layer that include a material with high hole injection properties, a material with high hole transport properties, a hole blocking material, a material with high electron transport properties, a material with high electron injection properties, an electron blocking material, or a bipolar material (a material with high electron transport and hole transport properties).

[0103] The EL layer 115 can use either low-molecular-weight compounds or high-molecular-weight compounds, and may also contain inorganic compounds. Each of the layers constituting the EL layer 115 can be formed by methods such as vapor deposition (including vacuum deposition), transfer, printing, inkjet, and coating.

[0104] When a voltage higher than the threshold voltage of the light-emitting element 120 is applied between the cathode and anode, holes are injected into the EL layer 115 from the anode side and electrons are injected from the cathode side. The injected electrons and holes recombine in the EL layer 115, causing the light-emitting material contained in the EL layer 115 to emit light.

[0105] When a white-emitting light-emitting element is used as the light-emitting element 120, it is preferable to have a configuration in which the EL layer 115 contains two or more types of light-emitting materials. For example, white emission can be obtained by selecting two or more light-emitting materials such that the emission of each of the two or more materials is in a complementary color relationship. For example, it is preferable to include two or more light-emitting materials that emit R (red), G (green), B (blue), Y (yellow), O (orange), etc., or light-emitting materials that emit light containing spectral components of two or more colors from R, G, and B. Furthermore, it is preferable to use a light-emitting element in which the emission spectrum from the light-emitting element has two or more peaks within the wavelength range of the visible light region (for example, 350 nm to 750 nm). In addition, it is preferable that the emission spectrum of a material having a peak in the yellow wavelength region also has spectral components in the green and red wavelength regions.

[0106] The EL layer 115 is preferably configured by laminating an emissive layer containing an emissive material that emits one color and an emissive layer containing an emissive material that emits another color. For example, the multiple emissive layers in the EL layer 115 may be laminated in contact with each other, or they may be laminated with regions that do not contain any emissive material in between. For example, a region may be provided between a fluorescent emissive layer and a phosphorescent emissive layer that contains the same material as the fluorescent emissive layer or the phosphorescent emissive layer (e.g., a host material, an assist material) but does not contain any emissive material. This makes it easier to manufacture the light-emitting element and reduces the driving voltage.

[0107] Furthermore, the light-emitting element 120 may be a single element (also called a single-structure device) having one EL layer, or it may be a tandem element (also called a tandem-structure device) in which multiple EL layers are stacked with a charge generation layer in between.

[0108] A single-structure device preferably has one light-emitting unit between a pair of electrodes, and this light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, light-emitting layers should be selected such that the light emitted from each of the two or more layers is complementary in color. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary, a configuration that emits white light as a whole can be obtained. The same applies to light-emitting devices having three or more light-emitting layers.

[0109] A tandem device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, the device should be configured such that the light from the light-emitting layers of the multiple light-emitting units is combined to produce white light emission. The configuration for obtaining white light emission is the same as that for a single-structure device. In a tandem device, it is preferable to provide an intermediate layer, such as a charge-generating layer, between the multiple light-emitting units.

[0110] Furthermore, when comparing the aforementioned white light-emitting devices (single or tandem structure) with SBS structure light-emitting devices, SBS structure light-emitting devices can consume less power than white light-emitting devices. If you want to keep power consumption low, it is preferable to use SBS structure light-emitting devices. On the other hand, white light-emitting devices are preferable because their manufacturing process is simpler than that of SBS structure light-emitting devices, which can lead to lower manufacturing costs or higher manufacturing yields.

[0111] A conductive film that transmits visible light, which can be used in the conductive layer 111, etc., can be formed using, for example, indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, or zinc oxide with gallium added. Metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, alloys containing these metal materials, or nitrides of these metal materials (e.g., titanium nitride) can also be used by forming them thinly enough to be translucent. Furthermore, a laminated film of the above materials can be used as the conductive layer. For example, using a laminated film of a silver-magnesium alloy and indium tin oxide is preferable because it can enhance conductivity. Graphene may also be used.

[0112] In the conductive layer 111, it is preferable to use a conductive film that reflects visible light in the portion located on the EL layer 115 side. As the conductive film, for example, a metallic material such as aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or an alloy containing these metallic materials, can be used. Silver is preferred because it has a high reflectivity of visible light. Aluminum is also preferred because it is easy to process as the electrodes are easily etched, and it has a high reflectivity of visible light and near-infrared light. Lanthanum, neodymium, or germanium may also be added to the metallic material or alloy. Alternatively, an alloy containing titanium, nickel, or neodymium and aluminum (aluminum alloy) may be used. Alternatively, an alloy containing copper, palladium, or magnesium and silver may be used. An alloy containing silver and copper is preferred because it has high heat resistance.

[0113] The conductive layer 111 may also be configured by laminating a conductive metal oxide film on a conductive film that reflects visible light. This configuration can suppress oxidation or corrosion of the conductive film that reflects visible light. For example, oxidation can be suppressed by laminating a metal film or metal oxide film in contact with an aluminum film or aluminum alloy film. Examples of materials for such metal films and metal oxide films include titanium or titanium oxide. Alternatively, a conductive film that transmits visible light and a film made of a metal material may be laminated. For example, a laminated film of silver and indium tin oxide, or a laminated film of a silver-magnesium alloy and indium tin oxide can be used.

[0114] When aluminum is used as the conductive layer 111, the reflectance of visible light and the like can be sufficiently high by making the thickness preferably 40 nm or more, and more preferably 70 nm or more. When silver is used as the conductive layer 111, the reflectance of visible light and the like can be sufficiently high by making the thickness preferably 70 nm or more, and more preferably 100 nm or more.

[0115] As a conductive film having light transmission and reflectivity that can be used in the conductive layer 116, a film can be used in which the conductive film that reflects visible light is formed to a thickness that allows visible light to pass through. Furthermore, by forming a laminated structure of the conductive film and the conductive film that transmits visible light, the conductivity or mechanical strength can be increased.

[0116] A conductive film having light-transmitting and reflective properties preferably has a reflectance to visible light (for example, reflectance to light of a predetermined wavelength within the range of 400 nm to 700 nm) of 20% to 80%, more preferably 40% to 70%. Furthermore, a conductive film having reflective properties preferably has a reflectance to visible light of 40% to 100%, more preferably 70% to 100%. Furthermore, a conductive film having light-transmitting properties preferably has a reflectance to visible light of 0% to 40%, more preferably 0% to 30%.

[0117] As the conductive layer 111 that functions as the lower electrode, metal materials such as aluminum, yttrium, zirconium, gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, tantalum, or titanium, alloys containing these metal materials, or nitrides of these metal materials (e.g., titanium nitride) can be used. These can also be suitably used as the conductive film of the plug 131.

[0118] The electrodes constituting the light-emitting element can be formed using methods such as vapor deposition or sputtering. Alternatively, they can be formed using ejection methods such as inkjet printing, printing methods such as screen printing, or plating methods.

[0119] Furthermore, the layers containing the light-emitting layer, as well as materials with high hole injection, high hole transport, high electron transport, high electron injection, bipolar materials, etc., may each contain inorganic compounds such as quantum dots, or polymer compounds (oligomers, dendrimers, polymers, etc.). For example, quantum dots can be used in the light-emitting layer to function as a light-emitting material.

[0120] Furthermore, as quantum dot materials, colloidal quantum dot materials, alloy-type quantum dot materials, core-shell type quantum dot materials, and core-type quantum dot materials can be used. Materials containing elemental groups from groups 12 and 16, 13 and 15, or 14 and 16 may also be used. Alternatively, quantum dot materials containing elements such as cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium, lead, gallium, arsenic, and aluminum may be used.

[0121] Preferably, each light-emitting element is adjusted such that the optical distance between the surface of its reflective layer that reflects visible light and the conductive layer 116 that is transparent and reflective to visible light is m × λ / 2 (where m is an integer of 1 or more) or close to that value, with respect to the wavelength λ of the light whose intensity is to be enhanced.

[0122] It should be noted that the optical distance described above is, strictly speaking, related to the product of the physical distance between the reflective surface of the reflective layer and the reflective surface of the conductive layer 116 which has both light transmission and reflectivity, and the refractive index of the layer provided between them, making it difficult to adjust precisely. Therefore, it is preferable to adjust the optical distance by assuming that the surface of the reflective layer and the surface of the conductive layer 116 which has both light transmission and reflectivity are reflective surfaces, respectively.

[0123] Materials that can be used for the plug 131 include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, gold, silver, platinum, magnesium, iron, cobalt, palladium, tantalum, or tungsten, alloys containing these metal materials, or nitrides of these metal materials. Furthermore, the plug 131 can be made by using a film containing these materials as a single layer or in a multilayer structure. For example, there are single-layer structures of aluminum film containing silicon, two-layer structures of aluminum film laminated on titanium film, two-layer structures of aluminum film laminated on tungsten film, two-layer structures of copper film laminated on copper-magnesium-aluminum alloy film, two-layer structures of copper film laminated on titanium film, two-layer structures of copper film laminated on tungsten film, three-layer structures of titanium film or titanium nitride film, with aluminum film or copper film laminated on top of that, and further titanium film or titanium nitride film formed on top of that, and three-layer structures of molybdenum film or molybdenum nitride film, with aluminum film or copper film laminated on top of that, and further molybdenum film or molybdenum nitride film formed on top of that. Oxides such as indium oxide, tin oxide, or zinc oxide may also be used. Furthermore, using copper containing manganese is preferable because it improves the controllability of the shape by etching.

[0124] [Example configuration of EL layer 115] The EL layer 115 of the light-emitting element 120 can be composed of multiple layers, such as layer 4420, light-emitting layer 4411, and layer 4430, as shown in Figure 3A. When the conductive layer 111 functions as the anode and the conductive layer 116 functions as the cathode, layer 4420 may have, for example, a layer containing a material with high electron injection properties (electron injection layer) and a layer containing a material with high electron transport properties (electron transport layer). The light-emitting layer 4411 may have, for example, a light-emitting compound. Layer 4430 may have, for example, a layer containing a material with high hole injection properties (hole injection layer) and a layer containing a material with high hole transport properties (hole transport layer). Note that when the conductive layer 111 functions as the cathode and the conductive layer 116 functions as the anode, layer 4420 may have, for example, a hole injection layer and a hole transport layer, the light-emitting layer 4411 may have, for example, a light-emitting compound, and layer 4430 may have, for example, an electron injection layer and an electron transport layer.

[0125] A configuration having a layer 4420, a light-emitting layer 4411, and a layer 4430 provided between a pair of electrodes can function as a single light-emitting unit, and in this specification, the configuration shown in Figure 3A is referred to as a single structure.

[0126] Furthermore, Figure 3B shows a modified version of the EL layer 115 of the light-emitting element 120 shown in Figure 3A. Specifically, the light-emitting element 120 shown in Figure 3B has a layer 4430-1 on the conductive layer 111, a layer 4430-2 on layer 4430-1, a light-emitting layer 4411 on layer 4430-2, a layer 4420-1 on the light-emitting layer 4411, a layer 4420-2 on layer 4420-1, and a conductive layer 116 on layer 4420-2. For example, when the conductive layer 111 is the anode and the conductive layer 116 is the cathode, layer 4430-1 functions as a hole injection layer, layer 4430-2 functions as a hole transport layer, layer 4420-1 functions as an electron transport layer, and layer 4420-2 functions as an electron injection layer. Alternatively, when conductive layer 111 is used as the cathode and conductive layer 116 is used as the anode, layer 4430-1 functions as an electron injection layer, layer 4430-2 functions as an electron transport layer, layer 4420-1 functions as a hole transport layer, and layer 4420-2 functions as a hole injection layer. By using such a layer structure, it is possible to efficiently inject carriers into the light-emitting layer 4411 and improve the efficiency of carrier recombination within the light-emitting layer 4411.

[0127] Furthermore, as shown in Figure 3C, a configuration in which multiple light-emitting layers (light-emitting layer 4411, light-emitting layer 4412, and light-emitting layer 4413) are provided between layer 4420 and layer 4430 is also a variation of the single structure.

[0128] Furthermore, as shown in Figure 3D, a configuration in which multiple light-emitting units (EL layer 115a, EL layer 115b) are connected in series via an intermediate layer 4440 is referred to as a tandem structure in this specification. The intermediate layer 4440 may also be referred to as a charge generation layer. In this specification, the configuration shown in Figure 3D is referred to as a tandem structure, but it is not limited to this, and for example, a tandem structure may also be called a stacked structure. By using a tandem structure, a light-emitting element capable of high-brightness light emission can be made.

[0129] Furthermore, in Figures 3C and 3D, as shown in Figure 3B, layer 4420 and layer 4430 may be a laminated structure consisting of two or more layers.

[0130] In Figures 1B and 1C, the EL layer 115 is shown as a two-layer laminated structure. For example, EL layer 115R consists of layer 113R and layer 114R on top of layer 113R. Similarly, EL layer 115G consists of layer 113G and layer 114G on top of layer 113G. EL layer 115B consists of layer 113B and layer 114B on top of layer 113B.

[0131] In the following, when explaining matters common to layers 113R, 113G, and 113B, the symbols attached to the references may be omitted, and they may be referred to simply as layer 113. Similarly, layers 114R, 114G, and 114B may be referred to simply as layer 114.

[0132] When conductive layer 111 functions as the anode and conductive layer 116 functions as the cathode, layer 114 is a layer that includes at least an electron injection layer, for example, the electron injection layer. Also, layer 113 is all the layers included in the EL layer 115 other than layer 114. For example, when the light-emitting element 120 has an electron injection layer and an electron transport layer as layer 4420, and layer 114 is the electron injection layer, the layer 113 of the light-emitting element 120 shown in Figure 3A includes the electron transport layer, the light-emitting layer 4411, and the layer 4430. Also, the layer 113 of the light-emitting element 120 shown in Figure 3B includes layer 4420-1, the light-emitting layer 4411, the layer 4430-2, and the layer 4430-1. Also, the layer 113 of the light-emitting element 120 shown in Figure 3C includes the electron transport layer, the light-emitting layer 4411, the light-emitting layer 4412, the light-emitting layer 4413, and the layer 4430. Furthermore, the layer 113 of the light-emitting element 120 shown in Figure 3D includes an electron transport layer, an emissive layer 4411, a layer 4430, an intermediate layer 4440, and an EL layer 115b.

[0133] In the above configuration, layer 114 and layer 134 contain the same material. The same material means that the constituent elements are the same and the composition is approximately the same. Furthermore, the film thickness of layer 134 is approximately the same as the film thickness of layer 114.

[0134] [Hole injection layer] The hole injection layer is a layer that injects holes from the anode into the hole transport layer, and is a layer containing a material with high hole injection capabilities. Examples of materials with high hole injection capabilities include aromatic amine compounds and composite materials containing hole transport materials and acceptor materials (electron-accepting materials).

[0135] [Hole transport layer] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light-emitting layer. The hole transport layer is a layer containing a hole-transporting material. The hole-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having a hole mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher hole transport capabilities than electron transport. Preferred hole transport materials include π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, furan derivatives, etc.) and aromatic amines (compounds having an aromatic amine skeleton), which are materials with high hole transport capabilities.

[0136] [Electron transport layer] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light-emitting layer. The electron transport layer is a layer containing an electron-transporting material. The electron-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having an electron mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes. Examples of electron-transporting materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds.

[0137] [Electron injection layer] The electron injection layer is a layer containing a material with high electron injection capacity. Furthermore, the electron injection layer is a layer for increasing the efficiency of electron injection from the conductive layer 116, and it is preferable to use a material in which the difference between the work function value of the material used in the conductive layer 116 and the LUMO level value of the material used in the electron injection layer is small (0.5 eV or less). Therefore, the electron injection layer should contain lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-(quinolinolato)lithium (abbreviated as Liq), 2-(2-pyridyl)phenolate (abbreviated as LiPP), 2-(2-pyridyl)-3-pyridinolatritium (abbreviated as LiPPy), 4-phenyl-2-(2-pyridyl)phenolate (abbreviated as LiPPP), and lithium oxide (LiO2). x Alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. Rare earth metal compounds such as erbium fluoride (ErF3) can also be used. An electride may also be used in the electron injection layer. Examples of electrides include a substance obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum. The material that constitutes the electron transport layer can also be used.

[0138] Furthermore, a composite material obtained by mixing an organic compound and an electron donor may be used in the electron injection layer. Such a composite material exhibits excellent electron injection and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent in transporting the generated electrons. Specifically, for example, an electron transport material (metal complex, heteroaromatic compound, etc.) used in the electron transport layer can be used. The electron donor can be any substance that exhibits electron-donating properties to the organic compound. Specifically, alkali metals, alkaline earth metals, or rare earth elements are preferred, such as lithium, cesium, magnesium, calcium, erbium, and ytterbium. Alkali metal oxides or alkaline earth metal oxides are also preferred, such as lithium oxide, calcium oxide, and barium oxide. Lewis bases such as magnesium oxide can also be used. Furthermore, organic compounds such as tetrathiafulvalene (abbreviated as TTF) can also be used.

[0139] In addition, a composite material consisting of an organic compound and a metal may be used in the electron injection layer. Preferably, the organic compound used has a LUMO (Lowest Unoccupied Molecular Orbital) level between -3.6 eV and -2.3 eV. Furthermore, materials having lone pairs of electrons are preferred. Generally, the Highest Occupied Molecular Orbital (HOMO) level and LUMO level of the organic compound can be estimated using methods such as cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy.

[0140] Therefore, as the above organic compounds, materials having lone pairs of electrons, such as heterocyclic compounds having a pyridine skeleton, a diazine skeleton (pyrimidine, pyrazine, etc.), or a triazine skeleton, are preferred.

[0141] Examples of heterocyclic compounds containing a pyridine skeleton include 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), vasocuproin (abbreviation: BCP), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), and bathophenanthroline (abbreviation: BPhen). NBPhen has a higher glass transition temperature (Tg) and superior heat resistance compared to BPhen.

[0142] Furthermore, heterocyclic compounds having a diazine skeleton include 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), and 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f, Examples include [h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), and 4-{3-[3'-(9H-carbazole-9-yl)]biphenyl-3-yl}benzoflo[3,2-d]pyrimidine (abbreviation: 4mCzBPBfpm).

[0143] Furthermore, examples of heterocyclic compounds having a triazine skeleton include 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tz).

[0144] Furthermore, it is preferable to use transition metals belonging to Group 5, Group 7, Group 9, or Group 11 of the periodic table, or materials belonging to Group 13, as the metal. Examples of such metals include silver (Ag), copper (Cu), aluminum (Al), or indium (In). In this case, the organic compound forms a partially occupied molecular orbital (SOMO) with the metal.

[0145] Furthermore, the thickness of the electron injection layer is preferably 3 nm or more, and more preferably 5 nm or more. Also, the thickness of the electron injection layer is preferably 50 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less. This configuration reduces the influence of light absorption by the electron injection layer and provides a light-emitting element exhibiting high luminescence efficiency. Note that the thickness of the electron injection layer is not limited to the above; any thickness that allows it to function as an electron injection layer is acceptable. For example, the thickness of the electron injection layer may be 0.5 nm or more, or 1 nm or more. Also, the thickness of the electron injection layer may be 100 nm or less.

[0146] [Example of manufacturing method] An example of a method for manufacturing a display device according to one aspect of the present invention will be described with reference to Figures 4 to 9.

[0147] In Figures 4 to 9, A1, B1, C1, and D1 in each figure are cross-sectional views corresponding to the area indicated by the dashed line X1-X2 in Figure 1A. Also, A2, B2, C2, and D2 in each figure are cross-sectional views corresponding to the area indicated by the dashed line Y1-Y2 in Figure 1A.

[0148] Thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed using sputtering, chemical vapor deposition (CVD), vacuum deposition, pulsed laser deposition (PLD), ALD, and other methods. CVD methods include plasma-enhanced CVD (PECVD) and thermal CVD. One type of thermal CVD is metal-organic CVD (MOCVD).

[0149] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife coating, slit coating, roll coating, curtain coating, and knife coating.

[0150] Furthermore, when processing the thin film constituting the display device, it can be processed using methods such as photolithography. In addition, the thin film may be processed by nanoimprint lithography, sandblasting, lift-off lithography, etc. Furthermore, island-like thin films may be directly formed by a film deposition method using a shielding mask such as a metal mask. In this specification, "island-like" refers to a state in which two or more layers made of the same material and formed in the same process are physically separated.

[0151] There are two main methods of photolithography. One method involves forming a resist mask on the thin film to be processed, then processing the thin film by etching or other means, and removing the resist mask. The other method involves forming a photosensitive thin film, then exposing and developing it to process the thin film into the desired shape.

[0152] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture thereof. Other options include ultraviolet light, KrF laser light, or ArF laser light. Exposure may also be performed using immersion lithography. Furthermore, extreme ultraviolet (EUV) light or X-rays may be used as the light source for exposure. An electron beam can also be used instead of the light source. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because it allows for extremely fine processing. Note that a photomask is not required when exposure is performed by scanning a beam such as an electron beam.

[0153] Thin films can be processed using methods such as dry etching, wet etching, and sandblasting. The resist mask can be removed by dry etching (such as ashing), wet etching, wet etching after dry etching, or dry etching after wet etching.

[0154] For thin film planarization, polishing methods such as chemical mechanical polishing (CMP) are typically suitable. Other methods such as dry etching and plasma treatment may also be used. Polishing, dry etching, and plasma treatment may be performed multiple times, or they may be combined. When combining treatments, the order of the processes is not particularly limited and should be set appropriately according to the surface irregularities of the treated surface.

[0155] To precisely process a thin film to a desired thickness, for example, the CMP (Chemical Polishing) method can be used. In this method, the thin film is first polished at a constant processing speed until a portion of its upper surface is exposed. Then, by polishing at a slower processing speed until the thin film reaches the desired thickness, high-precision processing becomes possible.

[0156] Methods for detecting the end point of polishing include optical methods that involve irradiating the surface of the workpiece with light and detecting changes in the reflected light, physical methods that involve detecting changes in the polishing resistance that the processing equipment receives from the workpiece, and methods that involve applying magnetic field lines to the workpiece and using the changes in magnetic field lines caused by the resulting eddy currents.

[0157] After the upper surface of the thin film is exposed, the thickness of the thin film can be controlled with high precision by performing a polishing process at a slow processing speed while monitoring the thickness of the thin film using an optical method such as a laser interferometer. If necessary, the polishing process may be repeated multiple times until the thin film reaches the desired thickness.

[0158] [Example of manufacturing method 1] In the following explanation, we will use the display device 100 shown in Figures 1A to 1C, which was illustrated in the above configuration example, as an example.

[0159] {Preparation of substrate 101} As the substrate 101, a substrate having at least sufficient heat resistance to withstand subsequent heat treatment can be used. When an insulating substrate is used as the substrate 101, examples include glass substrates, quartz substrates, sapphire substrates, and ceramic substrates. In addition, semiconductor substrates such as single-crystal semiconductor substrates made of silicon or silicon carbide, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, and SOI substrates can be used.

[0160] In particular, it is preferable to use a substrate 101 on which a semiconductor circuit including semiconductor elements such as transistors is formed on the semiconductor substrate or the insulating substrate. It is preferable that the semiconductor circuit constitutes, for example, a pixel circuit, a gate line driving circuit (gate driver), a source line driving circuit (source driver), etc. In addition to the above, an arithmetic circuit, a memory circuit, etc. may also be configured.

[0161] In this embodiment, a substrate having at least a pixel circuit configured on it is used as the substrate 101.

[0162] {Formation of insulating layer 121 and plug 131} An insulating layer 121 is formed on the substrate 101. Next, an opening is formed in the insulating layer 121 at the position where the plug 131 will be formed, reaching the substrate 101. Preferably, this opening reaches an electrode or wiring provided on the substrate 101. Subsequently, a conductive film is formed to fill the opening, and then a planarization process is performed so that the upper surface of the insulating layer 121 is exposed. This makes it possible to form a plug 131 embedded in the insulating layer 121.

[0163] {Formation of light-emitting element 120R, light-emitting element 120G, light-emitting element 120B, and structure 132} A conductive film 111f is deposited on the insulating layer 121 and the plug 131 (see Figures 4A1 and 4A2). The conductive film 111f can be deposited using sputtering, CVD, MBE, PLD, ALD, or other appropriate methods.

[0164] Next, a film 113RF, which will become layer 113R, and a sacrificial film 141RF are sequentially deposited on the conductive film 111f (see Figures 4B1 and 4B2). As will be described in detail later, the sacrificial layer formed by processing the sacrificial film 141RF functions as a protective layer that protects the film (film 113Rf, described later) located below the sacrificial layer from damage in subsequent processes. The sacrificial layer may also function as a mask when processing the film (film 113Rf, described later) located below it. Therefore, in this specification, the sacrificial layer may be referred to as a mask layer or protective layer. The sacrificial film that becomes the sacrificial layer may also be referred to as a mask film or protective film.

[0165] The film 113RF has a film containing at least a luminescent compound. In addition, it may have a structure in which one or more films functioning as electron transport layers, charge generation layers, hole transport layers, or hole injection layers are stacked. The film 113RF can be formed by, for example, vapor deposition, sputtering, or inkjet. However, it is not limited to these, and the above-mentioned film formation methods can be used as appropriate.

[0166] For the deposition of the sacrificial film 141RF, for example, sputtering, ALD (thermal ALD, PEALD), or vacuum deposition can be used. A deposition method that minimizes damage to the film that will become layer 113 is preferred, and it is preferable to use ALD or vacuum deposition rather than sputtering to form the sacrificial film 141RF.

[0167] In addition to the above deposition methods, wet deposition methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating may also be used to deposit the sacrificial film 141RF.

[0168] It is preferable to use a sacrificial film 141RF that can be removed by a wet etching method. By using a wet etching method, the damage to the film that will become layer 113 during processing of the sacrificial film 141RF can be reduced compared to when a dry etching method is used. When using a wet etching method, it is preferable to use a chemical solution containing, for example, a developer, an aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0169] In the method for manufacturing the display device of this embodiment, it is desirable that the film that becomes layer 113 is difficult to process during the processing steps for the various sacrificial films, and that the various sacrificial films are difficult to process during the processing steps for the film that becomes layer 113. It is desirable to select the material and processing method for the sacrificial films, and the processing method for the film that becomes layer 113, taking these factors into consideration.

[0170] As the sacrificial film 141RF, for example, an inorganic film such as a metal film, alloy film, metal oxide film, semiconductor film, or inorganic insulating film can also be used.

[0171] As the sacrificial film 141RF, for example, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metallic materials, can be used.

[0172] Furthermore, metal oxides such as indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO) can be used as the sacrificial film 141RF. In addition, indium oxide, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc. can be used. Alternatively, indium tin oxide containing silicon can also be used.

[0173] In addition, element M (where M is one or more selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) may be used instead of gallium. In particular, it is preferable that M be one or more selected from gallium, aluminum, or yttrium.

[0174] Furthermore, various inorganic insulating films that can be used for the insulating layer 117 or insulating layer 118 can be used as the sacrificial film 141RF. In particular, oxide insulating films are preferred because they have higher adhesion to the film that will become layer 113 compared to nitride insulating films. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used as the sacrificial film 141RF. In particular, forming an aluminum oxide film using the ALD method is preferable for the sacrificial film 141RF because it can reduce damage to the substrate (especially the EL layer).

[0175] Alternatively, the sacrificial film 141RF may be made of a material that is soluble in a chemically stable solvent, at least for the film located at the top of the film 113RF. For example, a material soluble in water or alcohol may be used for the sacrificial film 141RF. When forming the sacrificial film 141RF using such a material, it is preferable to dissolve the material in a solvent such as water or alcohol, apply it using the wet film formation method described above, and then perform a heat treatment to evaporate the solvent. At this time, by performing the heat treatment under a reduced pressure atmosphere, the solvent can be removed at a low temperature and in a short time, thereby reducing thermal damage to the film 113RF.

[0176] Materials that dissolve in water or alcohol include organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resins.

[0177] Next, a resist mask 151R is formed on the sacrificial film 141RF (see Figures 4B1 and 4B2). Preferably, the width of the resist mask 151R in the X1-X2 direction is greater than the width of the conductive layer 111R that is formed later.

[0178] The resist mask 151R can use a resist material containing a photosensitive resin, such as a positive-type resist material or a negative-type resist material.

[0179] In Figure 4B1, in a cross-sectional view of the display device 100, the edge of the resist mask 151R is perpendicular or approximately perpendicular to the substrate 101, but the shape of the edge of the resist mask 151R is not limited to this. The edge of the resist mask 151R may have a tapered shape or an inverse tapered shape. A tapered shape refers to a case where, when the side surface of a layer (here, corresponding to the resist mask 151R) is observed from the cross-sectional direction (a plane perpendicular to the surface of the substrate), the angle between the side surface and the bottom surface of the layer is less than 90°. An inverse tapered shape refers to a case where, when the side surface of a layer (here, corresponding to the resist mask 151R) is observed from the cross-sectional direction (a plane perpendicular to the surface of the substrate), the angle between the side surface and the bottom surface of the layer is greater than 90°. Alternatively, an inverse tapered shape is a shape having a side or top that protrudes from the bottom in a direction parallel to the substrate.

[0180] Next, the sacrificial layers 141RF and 113RF, which are not covered by the resist mask 151R, are removed, thereby exposing a portion of the upper surface of the conductive film 111f (see Figures 4C1 and 4C2). This allows the sacrificial layers 141R and 113Rf to be formed.

[0181] Dry etching or wet etching can be used to remove a portion of the sacrificial film 141RF and film 113RF. In particular, anisotropic dry etching is preferred because it prevents the exposed sides of film 113Rf from being etched, thus preventing the pattern of film 113Rf from shrinking after etching. The removal of a portion of the sacrificial film 141RF and the removal of a portion of film 113RF may be carried out under the same conditions or under different conditions.

[0182] Next, the resist mask 151R is removed (see Figures 4C1 and 4C2). It is preferable that the sacrificial layer 141R is provided on the film 113Rf so that the film 113Rf is not exposed to the chemicals used when removing the resist mask 151R.

[0183] When the above process is completed, it is preferable that the sacrificial layer 141R remains on the film 113Rf. This allows the sacrificial layer 141R to function as a protective layer that protects the film 113Rf from damage in subsequent processes.

[0184] Next, the film 113GF, which will become layer 113G, and the sacrificial film 141GF are deposited sequentially on the sacrificial layer 141R and the conductive film 111f, respectively (see Figures 5A1 and 5A2). At this time, as shown in Figure 5A1, film 113GF has a region that is in contact with the side surface of film 113Rf.

[0185] The method for depositing film 113GF can be described in the same way as described for film 113RF above. Furthermore, the materials that can be used for sacrificial film 141GF, and the method for depositing sacrificial film 141GF, can be described in the same way as described for sacrificial film 141RF above.

[0186] Next, a resist mask 151G is formed on the sacrificial film 141GF (see Figures 5A1 and 5A2). As shown in Figure 5A1, it is preferable that one side of the resist mask 151G is located near one side of the film 113Rf, and more preferably that it roughly coincides with that side of the film 113Rf. This makes it possible to arrange the light-emitting elements at an extremely high density, and the resolution of the display device 100 can be made extremely high.

[0187] The resist mask 151G can use a resist material containing a photosensitive resin, such as a positive-type resist material or a negative-type resist material.

[0188] In Figures 5A1 and 5A2, the edges of the resist mask 151G are approximately perpendicular to the substrate 101 in a cross-sectional view of the display device 100, but the shape of the edges of the resist mask 151G is not limited to this. The edges of the resist mask 151G may have a tapered shape or an inverse tapered shape.

[0189] Next, by removing the sacrificial film 141GF and film 113GF that are not covered by the resist mask 151G, a portion of the upper surface of the conductive film 111f and the upper surface of the sacrificial layer 141R are exposed (see Figures 5B1 and 5B2). This allows the sacrificial layer 141G and film 113Gf to be formed.

[0190] Dry etching or wet etching can be used to remove a portion of the sacrificial film 141GF and film 113GF. In particular, anisotropic dry etching is preferred because it prevents the exposed sides of film 113Gf from being etched, thus preventing the pattern of film 113Gf from shrinking after etching. The removal of a portion of the sacrificial film 141GF and the removal of a portion of film 113GF may be carried out under the same conditions or under different conditions.

[0191] Furthermore, as shown in Figure 5B1, the film 113Gf may have a protrusion at the end facing the film 113Rf. In this case, the sacrificial layer 141G may have a protrusion in the region overlapping with the protrusion of the film 113Gf. Note that Figure 5B1 shows a configuration where the ends of the protrusions of the film 113Gf and the sacrificial layer 141G are roughly perpendicular to the substrate 101, but the shape of the ends of the protrusions of the film 113Gf and the sacrificial layer 141G is not limited to this. The ends of the protrusions of the film 113Gf and / or the sacrificial layer 141G may have a tapered shape.

[0192] Depending on the shape of the resist mask 151G and the method of removing a portion of the sacrificial film 141GF and film 113GF, film 113Gf and / or the sacrificial layer 141G may not have any protrusions.

[0193] Next, the resist mask 151G is removed (see Figures 5B1 and 5B2). It is preferable that the sacrificial layer 141G is provided on the film 113Gf, as this prevents the film 113Gf from being exposed to the chemicals used to remove the resist mask 151G.

[0194] When the above process is completed, it is preferable that the sacrificial layer 141R remains on the film 113Rf and the sacrificial layer 141G remains on the film 113Gf. This allows the sacrificial layers 141R and 141G to function as protective layers that protect the film 113Rf and film 113Gf from damage in subsequent processes. Figure 5B1 shows a configuration in which each of the film 113Gf and the sacrificial layer 141G has a protrusion at its end, but the shape of the ends of the film 113Gf and the sacrificial layer 141G is not limited to this. The film 113Gf and / or the sacrificial layer 141G may not have a protrusion at its end.

[0195] Next, the film 113BF, which will become layer 113B, and the sacrificial film 141BF are sequentially deposited on the sacrificial layer 141R, the sacrificial layer 141G, and the conductive film 111f, respectively (see Figures 5C1 and 5C2). At this time, as shown in Figure 5C1, the film 113BF has a region in contact with the side surface of film 113Rf and a region in contact with the side surface of film 113Gf.

[0196] The method for depositing film 113BF can be described in the same way as described above for film 113RF. Furthermore, the materials that can be used for sacrificial film 141BF, and the method for depositing sacrificial film 141BF, can be described in the same way as described above for sacrificial film 141RF.

[0197] Next, a resist mask 151B is formed on the sacrificial film 141BF (see Figures 5C1 and 5C2). As shown in Figure 5C1, it is preferable that one side of the resist mask 151B is located near one side of the film 113Gf, and more preferably that it roughly coincides with that side of the film 113Gf. This makes it possible to arrange the light-emitting elements at an extremely high density, and the resolution of the display device 100 can be made extremely high. It is also preferable that the other side of the resist mask 151B is located near the other side of the film 113Rf, and more preferably that it roughly coincides with that side of the film 113Rf. This makes it possible to arrange the light-emitting elements at an extremely high density, and the resolution of the display device 100 can be made extremely high.

[0198] The resist mask 151B can use a resist material containing a photosensitive resin, such as a positive-type resist material or a negative-type resist material.

[0199] In Figures 5C1 and 5C2, the edges of the resist mask 151B are perpendicular or approximately perpendicular to the substrate 101 in a cross-sectional view of the display device 100, but the shape of the edges of the resist mask 151B is not limited to this. The edges of the resist mask 151B may have a tapered shape or an inverse tapered shape.

[0200] Next, by removing the sacrificial films 141BF and 113BF that are not covered by the resist mask 151B, a portion of the upper surface of the conductive film 111f, the upper surface of the sacrificial layer 141R, and the upper surface of the sacrificial layer 141G are exposed (see Figures 5D1 and 5D2). This allows the sacrificial layer 141B and film 113Bf to be formed.

[0201] Dry etching or wet etching can be used to remove a portion of the sacrificial film 141BF and film 113BF. In particular, anisotropic dry etching is preferred because it prevents the exposed sides of film 113Bf from being etched, thus preventing the pattern of film 113Bf from shrinking after etching. The removal of a portion of the sacrificial film 141BF and the removal of a portion of film 113BF may be carried out under the same conditions or under different conditions.

[0202] Furthermore, as shown in Figure 5D1, the film 113Bf may have protrusions at the end in contact with film 113Rf and at the end in contact with film 113Gf. In this case, the sacrificial layer 141B may have protrusions in the region that overlaps with the protrusions of film 113Bf. Note that Figure 5D1 shows a configuration in which the ends of the protrusions of film 113Bf and sacrificial layer 141B are perpendicular or approximately perpendicular to the substrate 101, but the shape of the ends of the protrusions of film 113Bf and sacrificial layer 141B is not limited to this. The ends of the protrusions of film 113Bf and / or sacrificial layer 141B may have a tapered shape.

[0203] Depending on the shape of the resist mask 151B and the method of removing a portion of the sacrificial film 141BF and film 113BF, film 113Bf and / or sacrificial layer 141B may not have any protrusions.

[0204] Next, the resist mask 151B is removed (see Figures 5D1 and 5D2). It is preferable that the sacrificial layer 141B is provided on the film 113Bf so that the film 113Bf is not exposed to the chemicals used when removing the resist mask 151B.

[0205] When the above process is completed, it is preferable that the sacrificial layer 141R remains on film 113Rf, the sacrificial layer 141G remains on film 113Gf, and the sacrificial layer 141B remains on film 113Bf. This allows the sacrificial layers 141R, 141G, and 141B to function as protective layers that protect film 113Rf, film 113Gf, and film 113Bf from damage in subsequent processes. Figure 5D1 shows a configuration in which each of film 113Gf, film 113Bf, sacrificial layer 141G, and sacrificial layer 141B has a protrusion at its end, but the shape of the ends of each of film 113Gf, film 113Bf, sacrificial layer 141G, and sacrificial layer 141B is not limited to this. One or more of film 113Gf, film 113Bf, sacrificial layer 141G, and sacrificial layer 141B may not have a protrusion at its end.

[0206] Next, sacrificial layers 141R, 141G, and 141B are removed, exposing the upper surfaces of film 113Rf, film 113Gf, and film 113Bf. (See Figures 6A1 and 6A2.)

[0207] Sacrificial layers 141R, 141G, and 141B can be removed by wet etching or dry etching. In this case, it is preferable to use a method that causes as little damage as possible to films 113Rf, 113Gf, and 113Bf.

[0208] When inorganic films are used as sacrificial layers 141R, 141G, and 141B, it is preferable to use wet etching with, for example, an aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof, to remove sacrificial layers 141R, 141G, and 141B.

[0209] Alternatively, when organic materials are used as sacrificial layers 141R, 141G, and 141B, it is preferable to remove the sacrificial layers 141R, 141G, and 141B by dissolving them in a solvent such as water or alcohol.

[0210] Here, various alcohols can be used as the alcohol that can dissolve sacrificial layer 141R, sacrificial layer 141G, and sacrificial layer 141B, such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0211] Figure 6A1 shows a configuration in which each of the films 113Gf and 113Bf has a protrusion at its end, but the shape of the ends of each of the films 113Gf and 113Bf is not limited to this. Depending on the shape of the ends of films 113Gf, 113Bf, sacrificial layer 141G, and sacrificial layer 141B, and the method of removing sacrificial layer 141R, sacrificial layer 141G, and sacrificial layer 141B, each of the films 113Gf and 113Bf may not have a protrusion at its end.

[0212] After removing sacrificial layers 141R, 141G, and 141B, it is preferable to perform a drying treatment to remove water contained inside films 113Rf, 113Gf, and 113Bf, as well as water adsorbed on the surface. For example, it is preferable to perform a heat treatment under an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 120°C. A reduced pressure atmosphere is preferable because it allows drying at a lower temperature.

[0213] Next, film 114f and conductive film 116f are deposited sequentially on film 113Rf, film 113Gf, and film 113Bf (see Figures 6B1 and 6B2). If film 113Gf and film 113Bf each have protrusions at their edges, then, as shown in Figure 6B1, film 114f and conductive film 116f each have protrusions in the region that overlaps with the protrusions of film 113Gf and film 113Bf. If film 113Gf and film 113Bf each do not have protrusions at their edges, then film 114f and conductive film 116f each may not have protrusions.

[0214] For example, the film 114f may be a film containing a material that can be used in the electron injection layer described above. Examples of materials that can be used in the electron injection layer include alkali metals, alkaline earth metals, compounds thereof, and composite materials obtained by mixing organic compounds with metals. Specifically, the film 114f may be a film containing lithium fluoride (LiF), a film containing NBPhen and Ag, etc.

[0215] The method for depositing film 114f can be described using the same method as for film 113RF described above.

[0216] The conductive film 116f can be formed by, for example, sputtering or vacuum deposition.

[0217] Next, resist masks 152R, 152G, 152B, and 152P are formed on the conductive film 116f (see Figures 6B1 and 6B2).

[0218] In the following, when explaining matters common to resist masks 152R, 152G, and 152B, the symbols attached to the references may be omitted, and the mask may simply be referred to as resist mask 152.

[0219] The resist mask 152R is formed to overlap with the film 113Rf. The resist mask 152R also has a region that overlaps with the plug 131. Preferably, the width of the resist mask 152R in the X1-X2 direction is smaller than the width of the film 113Rf. Furthermore, if the film 114f and the conductive film 116f each have protrusions, it is preferable that the resist mask 152R does not overlap with the protrusions of the film 114f, and more preferably that it does not overlap with the protrusions of the conductive film 116f. Note that Figure 6B1 shows a configuration in which the side surface of the resist mask 152R is in contact with the side surface of the protrusions of the conductive film 116f.

[0220] The resist mask 152G is formed to overlap with the film 113Gf. The resist mask 152G also has a region that overlaps with the plug 131. Preferably, the width of the resist mask 152G in the X1-X2 direction is smaller than the width of the film 113Gf. Furthermore, if the film 114f and the conductive film 116f each have protrusions, it is preferable that the resist mask 152G does not overlap with the protrusions of the film 113Gf, more preferably with the protrusions of the film 114f, and even more preferably with the protrusions of the conductive film 116f. Note that Figure 6B1 shows a configuration in which the side surface of the resist mask 152G is in contact with the side surface of the protrusions of the conductive film 116f.

[0221] The resist mask 152B is formed to overlap with the film 113Bf. The resist mask 152B also has a region that overlaps with the plug 131. Preferably, the width of the resist mask 152B in the X1-X2 direction is smaller than the width of the film 113Bf. Furthermore, if the film 114f and the conductive film 116f each have protrusions, it is preferable that the resist mask 152B does not overlap with the protrusions of the film 113Bf, more preferably with the protrusions of the film 114f, and even more preferably with the protrusions of the conductive film 116f. Note that Figure 6B1 shows a configuration in which the side surface of the resist mask 152B is in contact with the side surface of the protrusions of the conductive film 116f.

[0222] Furthermore, the shortest distance (distance L1 shown in Figure 6B1) from one side of resist mask 152R to the other side of resist mask 152G, which face each other in the X1-X2 direction, can be appropriately set according to the film thickness of the insulating layer 117, processing accuracy, fineness, etc. For example, distance L1 is set to 50 nm or more and 600 nm or less, preferably 100 nm or more and 500 nm or less, and more preferably 150 nm or more and 400 nm or less.

[0223] Furthermore, the preferred range of distance L1 can be applied to the shortest distance from the side of resist mask 152R to the side of resist mask 152B that are facing each other in the X1-X2 direction. It can also be applied to the shortest distance from the side of resist mask 152G to the side of resist mask 152B that are facing each other in the X1-X2 direction.

[0224] Furthermore, the preferred range of distance L1 can be applied to the shortest distance between the opposing sides of adjacent resist masks 152 in the Y1-Y2 direction.

[0225] By using the above configuration, it is possible to arrange the light-emitting elements at an extremely high density, thereby achieving an extremely high resolution for the display device 100.

[0226] Depending on the resolution of the display device, it may not be necessary for the side surface of the resist mask 152 of the light-emitting element 120 to be in contact with the side surface of the conductive film 116f, as shown in Figures 8A1 and 8A2.

[0227] The resist mask 152P is formed in a region that does not overlap with films 113Rf, 113Gf, and 113Bf.

[0228] The resist mask 152 and the resist mask 152P can use a resist material containing a photosensitive resin, such as a positive-type resist material or a negative-type resist material.

[0229] Next, the conductive films 116f, 114f, 113Rf, 113Gf, 113Bf, and 111f, which are not covered by the resist mask 152 and resist mask 152P, are removed to expose a portion of the upper surface of the insulating layer 121.

[0230] Through the above processing, conductive layers 116 (conductive layer 116R, conductive layer 116G, and conductive layer 116B) and conductive layer 135 are formed from the conductive film 116f (see Figures 6C1 and 6C2). Since conductive layers 116 and 135 are formed by processing the conductive film 116f, conductive layers 116 and 135 contain the same material.

[0231] Furthermore, layers 114 (layers 114R, 114G, and 114B) and 134 are formed from the film 114f (see Figures 6C1 and 6C2). Since layers 114 and 134 are formed by processing the film 114f, layers 114 and 134 contain the same material.

[0232] Furthermore, layer 113R is formed from film 113Rf, layer 113G is formed from film 113Gf, and layer 113B is formed from film 113Bf (see Figures 6C1 and 6C2).

[0233] Furthermore, conductive layers 111 (conductive layers 111R, 111G, and 111B) and conductive layer 133 are formed from the conductive film 111f (see Figures 6C1 and 6C2). Since conductive layers 111 and 133 are formed by processing the conductive film 111f, conductive layers 111 and 133 contain the same material. Also, conductive layer 111 is electrically connected to plug 131.

[0234] Dry etching or wet etching can be used to remove a portion of conductive film 116f, a portion of film 114f, a portion of film 113Rf, a portion of film 113Gf, a portion of film 113Bf, and a portion of conductive film 111f. The removal of a portion of conductive film 116f, a portion of film 114f, a portion of film 113Rf, a portion of film 113Gf, a portion of film 113Bf, and a portion of conductive film 111f may be carried out under the same conditions or under different conditions.

[0235] As a result of the above processing, a portion of the insulating layer 121 in areas that do not overlap with the resist mask 152 and resist mask 152P may be removed. In this case, as shown in Figure 2B, the insulating layer 121 has a recess in the area that does not overlap with the conductive layer 111. In other words, the film thickness of the insulating layer 121 in the area that does not overlap with the conductive layer 111 is thinner than the film thickness of the insulating layer 121 in the area that overlaps with the conductive layer 111.

[0236] Next, remove resist mask 152 and resist mask 152P (see Figures 6C1 and 6C2).

[0237] As described above, a light-emitting element 120R composed of conductive layers 111R, 113R, 114R, and 116R can be formed, a light-emitting element 120G composed of conductive layers 111G, 113G, 114G, and 116G can be formed, a light-emitting element 120B composed of conductive layers 111B, 113B, 114B, and 116B can be formed, and a structure 132 composed of conductive layers 135, 134, and 133 can be formed.

[0238] The deposition order of films 113RF, 113GF, and 113BF is not limited to the above. For example, films may be deposited in the order of 113RF, 113BF, and 113GF. Alternatively, films may be deposited starting with 113GF or 113BF.

[0239] Furthermore, the manufacturing method should be appropriately adjusted according to the number of colors of light emitted by the light-emitting elements 120 included in the display device 100. For example, if the number of colors of light emitted by the light-emitting elements 120 included in the display device 100 is two, the process consisting of forming a film containing at least a luminescent compound and a sacrificial film, forming a resist mask, removing the sacrificial film and the film not covered by the resist mask, and removing the resist mask should be performed twice. Alternatively, if the number of colors of light emitted by the light-emitting elements 120 included in the display device 100 is four, the process should be performed four times.

[0240] According to the above example of the manufacturing method, by providing a sacrificial layer on layer 113, layer 113 is not exposed to the chemicals used when removing the resist mask 151R, resist mask 151G, and resist mask 151B. Therefore, the light-emitting element 120 can be formed without using a metal mask for the deposition of layer 113.

[0241] {Formation of insulating layer 117, insulating layer 118, and conductive layer 139} Next, insulating films 117f and 118f are sequentially deposited on the conductive layer 116R, conductive layer 116G, conductive layer 116B, conductive layer 135, and insulating layer 121, respectively (see Figures 7A1 and 7A2).

[0242] The insulating film 117f can be deposited using methods such as sputtering, CVD, MBE, PLD, or ALD as appropriate. In this embodiment, an aluminum oxide film is deposited as the insulating film 117f by the ALD method. The insulating film 117f needs to be deposited with good coverage on the sides of the conductive layer 116, the sides of layer 114, the sides of layer 113, and the sides of the conductive layer 111. The ALD method allows for the deposition of atomic layers one by one on these sides, thus enabling the deposition of the insulating film 117f with good coverage.

[0243] For example, when depositing an aluminum oxide film by the ALD method, two types of gases are used: a raw material gas obtained by vaporizing a liquid containing a solvent and an aluminum precursor compound (such as trimethylaluminum (TMA, Al(CH3)3)), and H2O as an oxidizing agent. Other materials include tris(dimethylamide)aluminum, triisobutylaluminum, and aluminum tris(2,2,6,6-tetramethyl-3,5-heptanedionate).

[0244] The insulating film 118f can be deposited using methods such as sputtering, CVD, MBE, PLD, or ALD as appropriate. In this embodiment, a silicon nitride film is deposited as the insulating film 118f.

[0245] When the insulating film 118f is formed by a method with low coverage, as shown in FIG. 2A, voids 137 may be formed between the insulating film 117f and the insulating film 118f between the light-emitting elements 120. Examples of the film formation method with low coverage include a sputtering method or a CVD method.

[0246] Further, as the insulating film 118f, two films having different materials and / or film formation methods may be formed. For example, an insulating film serving as the insulating layer 118a is formed on the insulating film 117f, and an insulating film serving as the insulating layer 118b is formed on the insulating film serving as the insulating layer 118a. Specifically, an insulating film serving as the insulating layer 118a is formed on the insulating film 117f by a sputtering method, and an insulating film serving as the insulating layer 118b is formed on the insulating film serving as the insulating layer 118a by an ALD method. Thereby, when pinholes or steps are formed in the film formed by the sputtering method, the film formed by the ALD method with good coverage can be used to close the portion overlapping with the pinholes or steps.

[0247] Subsequently, a resist mask 153 is formed on the insulating film 118f (see FIGS. 7A1 and 7A2).

[0248] The resist mask 153 can use a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0249] Subsequently, by removing the insulating film 也118f and the insulating film 117f not covered by the resist mask 153, a part of the upper surface of the conductive layer 116 and a part of the upper surface of the conductive layer 135 are exposed (see FIGS. 7B1 and 7B2). Thereby, the insulating layer 118 and the insulating layer 117 can be formed. Each of the insulating layer 118 and the insulating layer 117 has a first opening in a region overlapping at least a part of the conductive layer 135 and a second opening in a region overlapping at least a part of the conductive layer 116.

[0250] Subsequently, the resist mask 153 is removed (see FIGS. 7B1 and 7B2).

[0251] Subsequently, a conductive film 139f is formed on the conductive layer 116, on the conductive layer 135, and on the insulating layer 118 (see FIGS. 7C1 and 7C2). The conductive film 139f can be formed by appropriately using a sputtering method, a CVD method, an MBE method, a PLD method, an ALD method, or the like.

[0252] Subsequently, a resist mask 154 is formed on the conductive film 139f (see FIGS. 7C1 and 7C2).

[0253] The resist mask 154 can use a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0254] Subsequently, by removing the conductive film 139f not covered by the resist mask 154, a part of the upper surface of the insulating layer 118 is exposed (see FIGS. 7D1 and 7D2). Thereby, the conductive layer 139 can be formed. The conductive layer 139 has a region in contact with the conductive layer 135 through the first openings provided in the insulating layer 117 and the insulating layer 118. Further, the conductive layer 139 has a region in contact with the conductive layer 116 through the second openings provided in the insulating layer 117 and the insulating layer 118.

[0255] Subsequently, the resist mask 154 is removed (see FIGS. 7D1 and 7D2).

[0256] As described above, the display device 100 can be manufactured.

[0257] Furthermore, since the conductive layer 139 is formed uniformly in the region overlapping with the light-emitting element 120 and the structure 132, fine processing may not be required. For this reason, the conductive layer 139 may be formed using a metal mask. For example, as shown in Figures 8B1 and 8B2, the conductive layer 139 may be formed in region 171 using a metal mask. When forming the conductive layer 139 using a metal mask, the steps of forming the resist mask 154, removing the conductive film not covered by the resist mask 154, and removing the resist mask 154 can be omitted. Therefore, productivity can be improved by reducing the number of steps.

[0258] According to the above example of manufacturing method, the difference in optical distance between the conductive layer 111 and the conductive layer 116 can be precisely controlled by the thickness of the EL layer 115. As a result, color shifts in each light-emitting element are less likely to occur, and a display device with excellent color reproduction and extremely high display quality can be easily manufactured.

[0259] Furthermore, the light-emitting element 120 can be formed on an insulating layer 121 with a flattened upper surface. In addition, the lower electrode (conductive layer 111) of the light-emitting element 120 can be electrically connected to the pixel circuit of the substrate 101 via a plug 131, making it possible to form extremely fine pixels and realize an extremely high-definition display device. Moreover, since the light-emitting element 120 can be arranged in overlapping place with the pixel circuit or driving circuit, a display device with a high aperture ratio (effective light-emitting area ratio) can be realized.

[0260] [Example of manufacturing method 2] In the following explanation, we will use the display device 100 shown in Figure 2C, which was illustrated in the above configuration example, as an example.

[0261] In the following sections, we may refer to and omit explanations of parts that overlap with the above-mentioned manufacturing method example 1.

[0262] {Preparation of substrate 101} Similarly to the above, a substrate having at least a pixel circuit configured on it is used as substrate 101.

[0263] {Formation of insulating layer 121 and plug 131} Next, the insulating layer 121 and the plug 131 are formed (see Figures 4A1 and 4A2). The insulating layer 121 and the plug 131 can be formed by the same method as described above.

[0264] {Formation of light-emitting element 120R, light-emitting element 120G, light-emitting element 120B, and structure 132} Next, films 113Rf, 113Gf, and 113Bf are formed on the conductive film 111f (see Figures 6A1 and 6A2). Films 113Rf, 113Gf, and 113Bf can be formed by the same method as described above.

[0265] Next, film 114f is deposited on films 113Rf, 113Gf, and 113Bf (see Figures 9A1 and 9A2).

[0266] As shown in Figure 9A2, the film 114f is not deposited in the region where the structure 132 is formed. In other words, the film 114f is deposited in the region where the structure 132 is not formed. For example, the region where the film 114f is deposited is region 172 shown in Figure 9A2. Region 172 is the region where the light-emitting element 120 is formed, and is also the region where the structure 132 is not formed. In this case, it is preferable to use a metal mask for depositing the film 114f. With this configuration, the film 114f is not deposited in the region where the structure 132 is formed.

[0267] Next, a conductive film 116f is deposited on film 114f, and resist masks 152 (resist mask 152R, resist mask 152G, and resist mask 152B) and resist mask 152P are formed on the conductive film 116f (see Figures 9A1 and 9A2). The deposition of the conductive film 116f and the formation of resist masks 152 and 152P can be carried out by the same method as described above.

[0268] Note that the conductive film 116f may be formed over the entire upper surface of the conductive film 111f, or may be formed in the region 171 as shown in FIG. 9A2. When the conductive film 116f is formed in the region 171, the metal mask used when forming the conductive layer 139 can be used.

[0269] Subsequently, after removing the conductive film 116f, the film 114f, the film 113Rf, the film 113Gf, the film 113Bf, and the conductive film 111f that are not covered by the resist masks 152 and 152P, the resist masks 152 and 152P are removed (see FIGS. 9B1 and 9B2). The removal of the conductive film 116f, the film 114f, the film 113Rf, the film 113Gf, the film 113Bf, and the conductive film 111f that are not covered by the resist masks 152 and 152P, and the removal of the resist masks 152 and 152P can be performed by the same method as described above.

[0270] From the above, the light-emitting element 120R, the light-emitting element 120G, the light-emitting element 120B, and the structure 132 composed of the conductive layers 133 and 135 can be formed.

[0271] Note that the method for forming the structure 132 composed of the conductive layers 133 and 135 is not limited to the above. For example, after forming the film 114f and removing the film 114f in the region overlapping with the structure 132, the conductive film 116f may be formed, and then the structure 132 composed of the conductive layers 133 and 135 may be formed through a process.

[0272] Also, as shown in FIGS. 4B2, 5A2, and 5C2, the films 113RF, 113GF, and 113BF may be formed over the entire upper surface of the conductive film 111f, but are not limited thereto. The films 113RF, 113GF, and 113BF may not be formed in the region where the structure 132 is formed. For example, the region where the films 113RF, 113GF, and 113BF are formed may be the region 172 shown in FIGS. 9C1 and 9C2. At this time, the metal mask used when forming the film 114f can be used.

[0273] [Configuration Example 2] The following describes an example of a display device that has transistors.

[0274] [Configuration Example 2-1] Figure 10 is a schematic cross-sectional view of the display device 200A.

[0275] The display device 200A includes a substrate 201, light-emitting elements 120R, 120G, 120B, a capacitive element 240, and a transistor 210, etc.

[0276] The stacked structure from substrate 201 to capacitive element 240 corresponds to substrate 101 in the above configuration example 1.

[0277] The transistor 210 is a transistor in which a channel formation region is formed on a substrate 201. The substrate 201 can be a semiconductor substrate such as a single-crystal silicon substrate. The transistor 210 includes a portion of the substrate 201, a conductive layer 211, a low-resistance region 212, an insulating layer 213, and an insulating layer 214. The conductive layer 211 functions as a gate electrode. The insulating layer 213 is located between the substrate 201 and the conductive layer 211 and functions as a gate insulating layer. The low-resistance region 212 is a region of the substrate 201 doped with impurities and functions as either a source or a drain. The insulating layer 214 covers the side surface of the conductive layer 211 and functions as an insulating layer.

[0278] Furthermore, an element isolation layer 215 is provided between two adjacent transistors 210 so as to be embedded in the substrate 201.

[0279] Furthermore, an insulating layer 261 is provided covering the transistor 210, and a capacitive element 240 is provided on the insulating layer 261.

[0280] The capacitive element 240 has a conductive layer 241, a conductive layer 242, and an insulating layer 243 located between them. The conductive layer 241 functions as one electrode of the capacitive element 240, the conductive layer 242 functions as the other electrode of the capacitive element 240, and the insulating layer 243 functions as the dielectric of the capacitive element 240.

[0281] The conductive layer 241 is provided on the insulating layer 261 and is electrically connected to either the source or drain of the transistor 210 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided covering the conductive layer 241. The conductive layer 242 is provided in the region that overlaps with the conductive layer 241 via the insulating layer 243.

[0282] An insulating layer 121 is provided covering the capacitive element 240, and light-emitting elements 120R, 120G, and 120B are provided on the insulating layer 121. Here, the configurations of the light-emitting elements 120R, 120G, and 120B are shown using the configurations exemplified in Configuration Example 1-1 and Figure 1B, but the configurations are not limited to these, and various configurations exemplified above can be applied.

[0283] In the display device 200A, insulating layers 161, 162, and 163 are provided in this order to cover the conductive layer 139 on the light-emitting element 120. These three insulating layers function as protective layers to prevent impurities such as water from diffusing into the light-emitting element 120. It is preferable to use inorganic insulating films with low moisture permeability, such as silicon oxide film, silicon nitride film, or aluminum oxide film, for insulating layers 161 and 163. In addition, an organic insulating film with high light permeability can be used for insulating layer 162. By using an organic insulating film for insulating layer 162, the influence of the uneven shape below insulating layer 162 can be mitigated, and the surface on which insulating layer 163 is formed can be made smooth. As a result, defects such as pinholes are less likely to occur in insulating layer 163, and the moisture permeability of the protective layer can be further improved. Note that the configuration of the protective layer covering the light-emitting element 120 is not limited to this, and it may be a single layer, a two-layer structure, or a laminated structure of four or more layers.

[0284] On the insulating layer 163, a colored layer 165R overlapping with the light-emitting element 120R, a colored layer 165G overlapping with the light-emitting element 120G, and a colored layer 165B overlapping with the light-emitting element 120B are provided. For example, the colored layer 165R transmits red light, the colored layer 165G transmits green light, and the colored layer 165B transmits blue light. This makes it possible to increase the color purity of the light from each light-emitting element, thereby realizing a display device with higher display quality. Furthermore, by forming each colored layer on the insulating layer 163, the alignment of each light-emitting unit and each colored layer is easier compared to the case where the colored layers are formed on the substrate 202 described later, and an extremely high-definition display device can be realized.

[0285] The display device 200A has a substrate 202 on the viewing side. Substrate 202 and substrate 201 are bonded together by a translucent adhesive layer 164. As substrate 202, a translucent substrate such as a glass substrate, quartz substrate, sapphire substrate, or plastic substrate can be used.

[0286] This configuration makes it possible to realize a display device with extremely high resolution and high display quality.

[0287] [Configuration Example 2-2] Figure 11 is a schematic cross-sectional view of the display device 200B. The display device 200B differs from the display device 200A mainly in its transistor configuration.

[0288] Transistor 220 is a transistor in which a metal oxide (also called an oxide semiconductor) is applied to the semiconductor layer where the channel is formed.

[0289] The transistor 220 includes a semiconductor layer 221, an insulating layer 223, a conductive layer 224, a pair of conductive layers 225, an insulating layer 226, and a conductive layer 227, etc.

[0290] As the substrate 201 on which the transistor 220 is provided, the insulating substrate or semiconductor substrate described above can be used.

[0291] An insulating layer 232 is provided on the substrate 201. The insulating layer 232 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 201 to the transistor 220, and prevents oxygen from detaching from the semiconductor layer 221 to the substrate 201. As the insulating layer 232, for example, a film that is less permeable to hydrogen or oxygen than a silicon oxide film can be used, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0292] A conductive layer 227 is provided on an insulating layer 232, and an insulating layer 226 is provided covering the conductive layer 227. The conductive layer 227 functions as the first gate electrode of the transistor 220, and a portion of the insulating layer 226 functions as the first gate insulating layer. It is preferable to use an oxide insulating film, such as a silicon oxide film, for at least the portion of the insulating layer 226 that is in contact with the semiconductor layer 221. It is preferable that the upper surface of the insulating layer 226 is flattened.

[0293] The semiconductor layer 221 is provided on the insulating layer 226. Preferably, the semiconductor layer 221 has a metal oxide (also called an oxide semiconductor) film with semiconductor properties. Details of materials suitable for use in the semiconductor layer 221 will be described later.

[0294] A pair of conductive layers 225 are provided in contact with the semiconductor layer 221 and function as source and drain electrodes.

[0295] Furthermore, an insulating layer 228 is provided covering the top and side surfaces of the pair of conductive layers 225, as well as the side surfaces of the semiconductor layer 221, and an insulating layer 261b is provided on the insulating layer 228. The insulating layer 228 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing into the semiconductor layer 221 from the insulating layer 261b, etc., and to prevent oxygen from detaching from the semiconductor layer 221. As the insulating layer 228, an insulating film similar to that of the insulating layer 232 can be used.

[0296] An opening is provided in the insulating layer 228 and the insulating layer 261b that reaches the semiconductor layer 221. Inside this opening, an insulating layer 223 and a conductive layer 224 are embedded, which are in contact with the sides of the insulating layer 261b, the insulating layer 228, and the conductive layer 225, as well as the upper surface of the semiconductor layer 221. The conductive layer 224 functions as a second gate electrode, and the insulating layer 223 functions as a second gate insulating layer.

[0297] The upper surfaces of the conductive layer 224, the insulating layer 223, and the insulating layer 261b are flattened so that their heights are approximately the same, and the insulating layer 229 and insulating layer 261a are provided covering them.

[0298] In this specification, "approximately matching heights" refers to a configuration in which the heights from a reference surface (e.g., a flat surface such as the substrate surface) are equal in a cross-sectional view. For example, in the manufacturing process of semiconductor devices, planarization (typically CMP) may expose the surfaces of one or more layers. In this case, the surfaces subjected to CMP will have a configuration in which the heights from the reference surface are equal. Furthermore, "approximately matching heights" also includes cases where the heights are identical. However, the heights of multiple layers may differ depending on the processing apparatus, processing method, or material of the surface subjected to CMP. In this specification, this case is also treated as "approximately matching heights." For example, if there are two layers with different heights (here referred to as a first layer and a second layer) with respect to a reference surface, the difference between the height of the top surface of the first layer and the height of the top surface of the second layer being 20 nm or less is also considered "approximately matching heights."

[0299] Insulating layers 261a and 261b function as interlayer insulating layers. In addition, insulating layer 229 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing from insulating layer 261a, etc., to the transistor 220. As insulating layer 229, an insulating film similar to that used for insulating layers 228 and 232 can be used.

[0300] A plug 271, which is electrically connected to one of the pair of conductive layers 225, is provided so as to be embedded in the insulating layer 261a, insulating layer 229, and insulating layer 261b. Here, it is preferable that the plug 271 has a conductive layer 271a that covers the sides of the openings of each of the insulating layer 261a, insulating layer 261b, insulating layer 229, and insulating layer 228, and a part of the upper surface of the conductive layer 225, and a conductive layer 271b that is in contact with the upper surface of the conductive layer 271a. In this case, it is preferable to use a conductive material that does not easily allow hydrogen and oxygen to diffuse as the conductive layer 271a.

[0301] [Configuration Example 2-3] Figure 12 is a schematic cross-sectional view of the display device 200C. The display device 200C has a configuration in which a transistor 210 with a channel formed on a substrate 201 and a transistor 220 containing a metal oxide in the semiconductor layer where the channel is formed are stacked.

[0302] An insulating layer 261 is provided covering the transistor 210, and a conductive layer 251 is provided on the insulating layer 261. An insulating layer 262 is provided covering the conductive layer 251, and a conductive layer 252 is provided on the insulating layer 262. The conductive layers 251 and 252 each function as wiring. An insulating layer 263 and an insulating layer 232 are provided covering the conductive layer 252, and a transistor 220 is provided on the insulating layer 232. An insulating layer 265 is provided covering the transistor 220, and a capacitive element 240 is provided on the insulating layer 265. The capacitive element 240 and the transistor 220 are electrically connected by a plug 274.

[0303] Transistor 220 can be used as a transistor constituting a pixel circuit. Transistor 210 can also be used as a transistor constituting a pixel circuit, or as a transistor constituting a drive circuit (gate line drive circuit, source line drive circuit) for driving the pixel circuit. Furthermore, transistors 210 and 220 can be used as transistors constituting various circuits such as arithmetic circuits or memory circuits.

[0304] This configuration allows for the formation of not only pixel circuits but also drive circuits and other components directly beneath the light-emitting unit, making it possible to miniaturize the display device compared to cases where the drive circuits are located around the display area.

[0305] [Configuration Example 2-4] Figure 13 is a schematic cross-sectional view of the display device 200D. The main difference between the display device 200C and the display device 200D is that it has two stacked transistors made of oxide semiconductor material.

[0306] The display device 200D has a transistor 230 between transistors 210 and 220. Transistor 230 has the same configuration as transistor 220, except that it does not have a first gate electrode. However, transistor 230 may also be configured to have a first gate electrode.

[0307] An insulating layer 263 and an insulating layer 231 are provided covering the conductive layer 252, and a transistor 230 is provided on the insulating layer 231. The transistor 230 and the conductive layer 252 are electrically connected via a plug 273, the conductive layer 253, and the plug 272. In addition, an insulating layer 264 and an insulating layer 232 are provided covering the conductive layer 253, and a transistor 220 is provided on the insulating layer 232.

[0308] For example, transistor 220 functions as a transistor for controlling the current flowing through the light-emitting element 120. Transistor 230 functions as a selection transistor for controlling the selected state of a pixel. Transistor 210 functions as a transistor that constitutes a drive circuit for driving a pixel.

[0309] In this way, by stacking three or more layers on which transistors are formed, the area occupied by pixels can be further reduced, making it possible to realize a high-definition display device.

[0310] The following describes the components, such as transistors, that can be applied to display devices.

[0311] [Transistor] A transistor comprises a conductive layer that functions as a gate electrode, a semiconductor layer, a conductive layer that functions as a source electrode, a conductive layer that functions as a drain electrode, and an insulating layer that functions as a gate insulating layer.

[0312] The structure of the transistor in the display device according to one aspect of the present invention is not particularly limited. For example, it may be a planar transistor, a staggered transistor, or an inverse staggered transistor. It may also be a top-gate or bottom-gate transistor structure. Alternatively, gate electrodes may be provided above and below the channel.

[0313] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors with crystalline regions in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0314] The semiconductor layer of the transistor preferably has a metal oxide (also called an oxide semiconductor). In other words, the display device of this embodiment preferably uses a transistor (hereinafter referred to as an OS transistor) that uses a metal oxide in the channel formation region. The metal oxides that can be used in the OS transistor will be described in Embodiment 4.

[0315] Alternatively, silicon may be used as the semiconductor in which the transistor channel is formed. Amorphous silicon may be used as the silicon, but crystalline silicon is particularly preferred. For example, microcrystalline silicon, polycrystalline silicon, or single-crystal silicon are preferred. In particular, polycrystalline silicon can be formed at a lower temperature than single-crystal silicon and has higher field-effect mobility and higher reliability than amorphous silicon.

[0316] [Conductive layer] Materials that can be used for conductive layers such as the gate (gate terminal or gate electrode), source (source terminal, source region or source electrode), and drain (drain terminal, drain region or drain electrode) of a transistor, as well as various wirings and electrodes that constitute a display device, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or alloys mainly composed of these materials. Films containing these materials can be used as single layers or in a multilayer structure. For example, there are single-layer structures of aluminum film containing silicon, two-layer structures of aluminum film laminated on titanium film, two-layer structures of aluminum film laminated on tungsten film, two-layer structures of copper film laminated on copper-magnesium-aluminum alloy film, two-layer structures of copper film laminated on titanium film, two-layer structures of copper film laminated on tungsten film, three-layer structures of titanium film or titanium nitride film, with aluminum film or copper film laminated on top of that, and further titanium film or titanium nitride film formed on top of that, and three-layer structures of molybdenum film or molybdenum nitride film, with aluminum film or copper film laminated on top of that, and further molybdenum film or molybdenum nitride film formed on top of that. Oxides such as indium oxide, tin oxide, or zinc oxide may also be used. Furthermore, using copper containing manganese is preferable because it improves the controllability of the shape by etching.

[0317] [Insulating layer] In addition to resins such as acrylic resin and epoxy resin, and resins having siloxane bonds such as silicone, inorganic insulating materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon nitride, and aluminum oxide can also be used as insulating materials for each insulating layer.

[0318] In addition, in this specification, the oxynitride refers to a material having a higher oxygen content than nitrogen in its composition, and the nitride oxide refers to a material having a higher nitrogen content than oxygen in its composition. For example, when silicon oxynitride is described, it refers to a material having a higher oxygen content than nitrogen in its composition, and when silicon nitride oxide is described, it indicates a material having a higher nitrogen content than oxygen in its composition.

[0319] In addition, the light-emitting element is preferably provided between a pair of insulating films with low water permeability. Thereby, it is possible to suppress the intrusion of impurities such as water into the light-emitting element, and it is possible to suppress a decrease in the reliability of the device.

[0320] Examples of the insulating film with low water permeability include films containing nitrogen and silicon such as a silicon nitride film and a silicon oxynitride film, or films containing nitrogen and aluminum such as an aluminum nitride film. Further, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or the like may be used.

[0321] For example, the water vapor transmission rate of the insulating film with low water permeability is 1×10 -5 [g / (m 2 ·day)] or less, preferably 1×10 -6 [g / (m 2 ·day)] or less, more preferably 1×10 -7 [g / (m 2 ·day)] or less, even more preferably 1×10 -8 [g / (m 2 ·day)] or less.

[0322] [Configuration example of display module] Hereinafter, a configuration example of a display module having a display device according to an aspect of the present invention will be described.

[0323] FIG. 14A is a perspective schematic view of a display module 280. The display module 280 includes a display device 200 and an FPC 290. As the display device 200, each of the display devices (display devices 200A to 200D) exemplified in Configuration Example 2 above can be applied.

[0324] The display module 280 has a substrate 201 and a substrate 202. The substrate 202 also has a display unit 281. The display unit 281 is the area in the display module 280 that displays the image, and is the area in which light from each pixel provided in the pixel unit 284, which will be described later, can be seen.

[0325] Figure 14B shows a schematic perspective view illustrating the configuration of the substrate 201. The substrate 201 has a configuration in which a circuit section 282, a pixel circuit section 283 on the circuit section 282, and a pixel section 284 on the pixel circuit section 283 are stacked. In addition, the substrate 201 has a terminal section 285 for connecting to the FPC 290 in a portion that does not overlap with the pixel section 284. The terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286 composed of multiple wires.

[0326] The pixel section 284 has multiple pixels 284a arranged periodically. A magnified view of one pixel 284a is shown on the right side of Figure 14B. The pixel 284a has light-emitting elements 120R, 120G, and 120B.

[0327] The pixel circuit section 283 has a plurality of periodically arranged pixel circuits 283a. The plurality of pixel circuits 283a may be arranged in a stripe arrangement as shown in Figure 14B. In addition, various arrangement methods such as delta arrangement and pentile arrangement can be applied.

[0328] A single pixel circuit 283a is a circuit that controls the light emission of the three light-emitting elements of a single pixel 284a. A single pixel circuit 283a may be configured to have three circuits that control the light emission of a single light-emitting element. For example, a single pixel circuit 283a may have at least one selection transistor, one current control transistor (drive transistor), and a capacitive element for each light-emitting element. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain. This realizes an active-matrix type display device.

[0329] The circuit section 282 has circuits for driving each pixel circuit 283a of the pixel circuit section 283. For example, it is preferable to have a gate line drive circuit, a source line drive circuit, etc. In addition, it may also have an arithmetic circuit, a memory circuit, a power supply circuit, etc.

[0330] The FPC290 functions as wiring for supplying video signals or power potential, etc., to the circuit section 282 from an external source. An IC may also be mounted on the FPC290.

[0331] The display module 280 can be configured such that a pixel circuit section 283 or a circuit section 282 is stacked on the lower side of the pixel section 284, thereby enabling an extremely high aperture ratio (effective display area ratio) of the display section 281. For example, the aperture ratio of the display section 281 can be 40% or more and less than 100%, preferably 50% or more and 95%, and more preferably 60% or more and 95%. Furthermore, it is possible to arrange the pixels 284a at an extremely high density, enabling an extremely high resolution of the display section 281. For example, it is preferable that the pixels 284a are arranged in the display section 281 with a resolution of 20000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and a resolution of 20000 ppi or less, or 30000 ppi or less.

[0332] Because such a display module 280 is extremely high-resolution, it can be suitably used in VR devices such as head-mounted displays, or in glasses-type AR devices. For example, even in a configuration where the display part of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display part 281, so even when the display part is magnified with lenses, pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 280 is not limited to this, and can be suitably used in electronic devices with relatively small display parts. For example, it can be suitably used in the display part of wearable electronic devices such as wristwatches.

[0333] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0334] (Embodiment 2) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figure 15.

[0335] The display device shown in Figure 15A includes a pixel section 502, a drive circuit section 504, a protection circuit 506, and a terminal section 507. In one embodiment of the present invention, the display device may be configured without the protection circuit 506.

[0336] The pixel unit 502 has a plurality of pixel circuits 501 arranged in X rows and Y columns (where X and Y are independent natural numbers of 2 or more). Each pixel circuit 501 has a circuit for driving a display element.

[0337] The drive circuit section 504 includes drive circuits such as a gate driver 504a that outputs a scan signal to gate lines GL_1 to GL_X, and a source driver 504b that supplies data signals to data lines DL_1 to DL_Y. The gate driver 504a may be configured to include at least a shift register. The source driver 504b may be configured using, for example, multiple analog switches. Alternatively, the source driver 504b may be configured using a shift register or the like.

[0338] The terminal section 507 refers to the part of the device that is equipped with terminals for inputting power, control signals, and image signals from an external circuit to the display device.

[0339] The protection circuit 506 is a circuit that makes a wire it is connected to conduct when a potential outside a certain range is applied to that wire. The protection circuit 506 shown in Figure 15A is connected to various wires, such as the gate line GL, which is the wire between the gate driver 504a and the pixel circuit 501, or the data line DL, which is the wire between the source driver 504b and the pixel circuit 501.

[0340] Furthermore, the gate driver 504a and the source driver 504b may each be provided on the same substrate as the pixel section 502, or a separate substrate (for example, a drive circuit substrate made of a single-crystal semiconductor or polycrystalline semiconductor) on which the gate driver circuit or source driver circuit is formed may be mounted on the substrate by COG or TAB (Tape Automated Bonding).

[0341] In particular, it is preferable to arrange the gate driver 504a and the source driver 504b below the pixel section 502.

[0342] Furthermore, the multiple pixel circuits 501 shown in Figure 15A can be configured as shown in Figure 15B, for example.

[0343] The pixel circuit 501 shown in Figure 15B includes a transistor 552, a transistor 554, a capacitive element 562, and a light-emitting element 572. The pixel circuit 501 is also connected to data lines DL_n (where n is an integer between 1 and Y), gate lines GL_m (where m is an integer between 1 and X), potential supply lines VL_a and VL_b, etc.

[0344] A high power supply potential VDD is supplied to one of the potential supply lines VL_a and VL_b, and a low power supply potential VSS is supplied to the other. The current flowing through the light-emitting element 572 is controlled according to the potential supplied to the gate of transistor 554, thereby controlling the luminescence brightness from the light-emitting element 572.

[0345] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0346] (Embodiment 3) The following describes a pixel circuit equipped with a memory for correcting the grayscale displayed on a pixel, which is applicable to a display device according to one aspect of the present invention, and a display device having the same.

[0347] [Circuit Configuration] Figure 16A shows the circuit diagram of the pixel circuit 400. The pixel circuit 400 includes transistor M1, transistor M2, capacitor C1, and circuit 401. Wiring S1, S2, G1, and G2 are connected to the pixel circuit 400.

[0348] Transistor M1 has its gate connected to wiring G1, one of its source and drain connected to wiring S1, and the other connected to one electrode of capacitor C1. Transistor M2 has its gate connected to wiring G2, one of its source and drain connected to wiring S2, the other connected to the other electrode of capacitor C1, and circuit 401.

[0349] Circuit 401 is a circuit that includes at least one display element. Various elements can be used as the display element, but typically light-emitting elements such as organic EL elements or LED elements can be used. In addition to these, liquid crystal elements or MEMS (Micro Electro Mechanical Systems) elements can also be used.

[0350] Let node N1 be the node connecting transistor M1 and capacitor C1, and node N2 be the node connecting transistor M2 and circuit 401.

[0351] The pixel circuit 400 can maintain the potential of node N1 by turning off transistor M1. Similarly, it can maintain the potential of node N2 by turning off transistor M2. Furthermore, with transistor M2 in the off state, by writing a predetermined potential to node N1 via transistor M1, the potential of node N2 can be changed in accordance with the displacement of the potential of node N1 through capacitive coupling via capacitor C1.

[0352] Here, one or both of transistors M1 and M2 can be replaced with transistors using an oxide semiconductor, as exemplified in Embodiment 1. Therefore, the potentials of nodes N1 and N2 can be maintained for a long period of time with an extremely small off-current. Note that if the period for maintaining the potential of each node is short (specifically, when the frame frequency is 30 Hz or higher, for example), transistors using a semiconductor such as silicon may be used.

[0353] [Example of driving method] Next, an example of how the pixel circuit 400 operates will be explained using Figure 16B. Figure 16B is a timing chart related to the operation of the pixel circuit 400. For the sake of simplicity, the effects of various resistors such as wiring resistance, parasitic capacitance of transistors or wiring, and the threshold voltage of transistors will not be considered here.

[0354] In the operation shown in Figure 16B, one frame period is divided into period T1 and period T2. Period T1 is the period during which the potential is written to node N2, and period T2 is the period during which the potential is written to node N1.

[0355] [Period T1] During period T1, a potential is applied to both wires G1 and G2 to turn the transistor ON. Additionally, a fixed potential V is applied to wire S1. ref The first data potential V is supplied to wiring S2. w To supply.

[0356] Node N1 receives a potential V from wiring S1 via transistor M1. ref The following is given. Also, node N2 has a first data potential V from wiring S2 via transistor M2. w Therefore, the potential difference V is given to capacitor C1. w -V ref This state is maintained.

[0357] [Period T2] Next, during period T2, a potential is applied to wiring G1 to turn on transistor M1, and a potential is applied to wiring G2 to turn off transistor M2. In addition, a second data potential V is applied to wiring S1. data The following is supplied: A predetermined constant potential may be applied to the wiring S2, or it may be left in a floating state.

[0358] Node N1 receives a second data potential V from wiring S1 via transistor M1. data The following is given. At this time, due to capacitive coupling by capacitance C1, the second data potential V data Accordingly, the potential of node N2 changes by a potential dV. That is, circuit 401 has a first data potential V w The input potential will be the sum of the potential dV and the second data potential V. Note that although Figure 16B shows the potential dV as a positive value, it can also be a negative value. That is, the second data potential V data The potential is V ref It can be lower.

[0359] Here, the potential dV is roughly determined by the capacitance value of capacitor C1 and the capacitance value of circuit 401. If the capacitance value of capacitor C1 is sufficiently larger than the capacitance value of circuit 401, the potential dV is the second data potential V data The potential will be close to that.

[0360] In this way, the pixel circuit 400 can combine two types of data signals to generate a potential that is supplied to the circuit 401, which includes a display element, making it possible to perform grayscale correction within the pixel circuit 400.

[0361] Furthermore, the pixel circuit 400 can generate a potential exceeding the maximum potential that can be supplied to wiring S1 and wiring S2. For example, when using light-emitting elements, high dynamic range (HDR) display can be performed. Also, when using liquid crystal elements, overdrive driving can be realized.

[0362] [Examples of application] The pixel circuit 400EL shown in Figure 16C has circuit 401EL. Circuit 401EL has a light-emitting element EL, a transistor M3, and a capacitor C2.

[0363] Transistor M3 has its gate connected to one electrode of node N2 and capacitance C2, and one of its source and drain connected to potential V. H The wiring that provides the voltage is connected to one electrode of the light-emitting element EL. Capacitor C2 is connected to the other electrode at potential V com Connect to the wiring that provides the potential V. The light-emitting element EL has the other electrode at potential V. L Connect to the wiring that provides it.

[0364] Transistor M3 controls the current supplied to the light-emitting element EL. Capacitor C2 functions as a retaining capacitor. Capacitor C2 can be omitted if not needed.

[0365] Note that although this configuration shows the anode side of the light-emitting element EL connected to transistor M3, transistor M3 may also be connected to the cathode side. In that case, the potential V H and potential V L The value can be changed as needed.

[0366] The 400EL pixel circuit can supply a large current to the light-emitting element EL by applying a high potential to the gate of transistor M3, thereby enabling features such as HDR display. Furthermore, by supplying a correction signal to wiring S1 or S2, variations in the electrical characteristics of transistor M3 or the light-emitting element EL can be corrected.

[0367] Note that the circuit is not limited to the example shown in Figure 16C; other configurations including additional transistors or capacitors are also acceptable.

[0368] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0369] (Embodiment 4) This embodiment describes metal oxides (also called oxide semiconductors) that can be used in the OS transistor described in the above embodiment.

[0370] As semiconductor materials used in transistors, metal oxides with an energy gap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more, can be used. Typical examples include metal oxides containing indium.

[0371] The metal oxide preferably comprises, for example, indium, M (where M is one or more selected from gallium, aluminum, 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.

[0372] In particular, it is preferable to use an oxide (also written as IGZO) containing indium (In), gallium (Ga), and zinc (Zn) as the semiconductor layer.

[0373] When the semiconductor layer is an In-M-Zn oxide, it is preferable that the atomic ratio of In in the In-M-Zn oxide is equal to or greater than the atomic ratio of M. Examples of such In-M-Zn oxide atomic ratios include compositions where In:M:Zn=1:1:1 or close to it, In:M:Zn=1:1:2 or close to it, In:M:Zn=2:1:3 or close to it, In:M:Zn=3:1:2 or close to it, In:M:Zn=4:2:3 or close to it, In:M:Zn=4:2:4.1 or close to it, In:M:Zn=5:1:3 or close to it, In:M:Zn=5:1:6 or close to it, In:M:Zn=5:1:7 or close to it, In:M:Zn=5:1:8 or close to it, In:M:Zn=6:1:6 or close to it, In:M:Zn=5:2:5 or close to it, and so on. Note that "close to it" means a range of ±30% of the desired atomic ratio.

[0374] For example, when describing a composition with an atomic ratio of In:Ga:Zn = 4:2:3 or a similar ratio, it includes cases where, when the atomic ratio of In is 4, the atomic ratio of Ga is between 1 and 3, and the atomic ratio of Zn is between 2 and 4. Also, when describing a composition with an atomic ratio of In:Ga:Zn = 5:1:6 or a similar ratio, it includes cases where, when the atomic ratio of In is 5, the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is between 5 and 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn = 1:1:1 or a similar ratio, it includes cases where, when the atomic ratio of In is 1, the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is greater than 0.1 and 2 or less.

[0375] Furthermore, these are not the only options; an oxide semiconductor with an appropriate composition may be used depending on the required semiconductor characteristics and electrical characteristics (field-effect mobility, threshold voltage, etc.) of the transistor. In addition, it is preferable to set the carrier concentration, impurity concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. of the semiconductor layer appropriately in order to obtain the required semiconductor characteristics of the transistor.

[0376] Furthermore, metal oxides can be formed by methods such as sputtering, CVD (Chemical Vapor Deposition) methods including MOCVD, or ALD (Artificial Alkaline Dispersion).

[0377] <Classification of crystal structures> Examples of crystalline structures for oxide semiconductors include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and polycrystal.

[0378] The crystal structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectroscopy. For example, it can be evaluated using the XRD spectrum obtained by GIXD (Grazing-Incidence XRD) measurement. The GIXD method is also known as the thin-film method or the Seemann-Bohlin method.

[0379] For example, in a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, in an IGZO film with a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical shape of the XRD spectrum peak clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0380] Furthermore, the crystalline structure of a film or substrate can be evaluated by the diffraction pattern (also called the nano-beam electron diffraction pattern) observed using nano-beam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, confirming that the quartz glass is in an amorphous state. However, in the diffraction pattern of an IGZO film deposited at room temperature, a spot-like pattern is observed instead of a halo. Therefore, it is presumed that an IGZO film deposited at room temperature is in an intermediate state, neither crystalline nor amorphous, and cannot be concluded to be in an amorphous state.

[0381] <<Oxide semiconductor structure>> It should be noted that oxide semiconductors may be classified differently from those described above when considering their structure. For example, oxide semiconductors can be divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the aforementioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors also include polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0382] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0383] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, the c-axis of which is oriented in a specific direction. This specific direction is the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region with periodic atomic arrangement. If we consider the atomic arrangement as a lattice arrangement, then a crystalline region is also a region with a aligned lattice arrangement. Furthermore, CAAC-OS has regions where multiple crystalline regions are connected in the ab-plane direction, and these regions may exhibit distortion. Distortion refers to a point in the connected region where the orientation of the lattice arrangement changes between a region with a aligned lattice arrangement and another region with a aligned lattice arrangement. In short, CAAC-OS is an oxide semiconductor that is c-axis oriented and does not exhibit clear orientation in the ab-plane direction.

[0384] Each of the above-mentioned crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of one minute crystal, the maximum diameter of that crystalline region will be less than 10 nm. When a crystalline region is composed of many minute crystals, the maximum diameter of that crystalline region may be around several tens of nm.

[0385] Furthermore, in In-M-Zn oxides (where element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), CAAC-OS tends to have a layered crystalline structure (also called a layered structure) consisting of layers containing indium (In) and oxygen (hereinafter referred to as the In layer) and layers containing element M, zinc (Zn), and oxygen (hereinafter referred to as the (M,Zn) layer). Note that indium and element M are mutually substitutable. Therefore, the (M,Zn) layer may contain indium. Also, the In layer may contain element M. Also, the In layer may contain Zn. This layered structure can be observed, for example, as a lattice image in high-resolution TEM (Transmission Electron Microscope) images.

[0386] When structural analysis of a CAAC-OS film is performed using an XRD instrument, for example, out-of-plane XRD measurements using θ / 2θ scanning show a peak indicating c-axis orientation at 2θ = 31° or nearby. Note that the position of the c-axis orientation peak (value of 2θ) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0387] Furthermore, for example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film. These spots are observed at point-symmetric positions with respect to the incident electron beam spot (also called the direct spot) that passed through the sample.

[0388] When the crystal region is observed from the specific direction described above, the lattice arrangement within that crystal region is based on a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the strain may have lattice arrangements such as pentagons or heptagons. Moreover, in CAAC-OS, clear grain boundaries cannot be observed even near the strain. In other words, it can be seen that the formation of grain boundaries is suppressed by the strain in the lattice arrangement. This is thought to be because CAAC-OS can tolerate strain due to the sparse arrangement of oxygen atoms in the ab-plane direction, or because the bond distance between atoms changes due to the substitution of metal atoms.

[0389] Furthermore, a crystal structure in which clear grain boundaries can be observed is called a polycrystalline material. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in transistor on-current and field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries cannot be observed, is one of the crystalline oxides with a suitable crystal structure for the semiconductor layer of a transistor. In addition, a structure containing Zn is preferred for the composition of CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are preferred because they can suppress the generation of grain boundaries more effectively than In oxide.

[0390] CAAC-OS is an oxide semiconductor with high crystallinity and no clearly defined grain boundaries. Therefore, CAAC-OS is less susceptible to the decrease in electron mobility caused by grain boundaries. Furthermore, since the crystallinity of oxide semiconductors can decrease due to the inclusion of impurities or the generation of defects, CAAC-OS can be said to be an oxide semiconductor with few impurities or defects (such as oxygen vacancies). Consequently, oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat-resistant and highly reliable. In addition, CAAC-OS is stable even at high temperatures (so-called thermal budget) during the manufacturing process. Therefore, using CAAC-OS in OS transistors allows for greater flexibility in the manufacturing process.

[0391] [nc-OS] nc-OS exhibits periodicity in atomic arrangement in minute regions (e.g., regions between 1 nm and 10 nm, particularly between 1 nm and 3 nm). In other words, nc-OS contains minute crystals. These minute crystals are also called nanocrystals because their size is, for example, between 1 nm and 10 nm, particularly between 1 nm and 3 nm. Furthermore, nc-OS shows no regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Consequently, depending on the analytical method, nc-OS may be indistinguishable from a-like OS and amorphous oxide semiconductors. For example, when structural analysis of an nc-OS film is performed using an XRD instrument, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Also, when electron diffraction (also called limited-field electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of the nanocrystals (e.g., 50 nm or larger), a diffraction pattern resembling a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystal (for example, 1 nm to 30 nm), an electron diffraction pattern may be obtained in which multiple spots are observed within a ring-shaped region centered on a direct spot.

[0392] [a-like OS] a-like OS is an oxide semiconductor having a structure between nc-OS and amorphous oxide semiconductors. a-like OS has porous or low-density regions. That is, a-like OS has lower crystallinity compared to nc-OS and CAAC-OS. Also, a-like OS has a higher hydrogen concentration in the film compared to nc-OS and CAAC-OS.

[0393] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0394] [CAC-OS] CAC-OS is a material composition in which, for example, the elements constituting the metal oxide are unevenly distributed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size. In the following, a state in which one or more metal elements are unevenly distributed in a metal oxide, and the regions containing these metal elements are mixed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size, is also referred to as a mosaic or patchy state.

[0395] Furthermore, CAC-OS is a composite metal oxide having a mosaic-like structure formed by the separation of the material into a first region and a second region, with the first region distributed within the film (hereinafter also referred to as a cloud-like structure). In other words, CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0396] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS of In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of the CAC-OS film. The second region is the region where [Ga] is greater than the [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is the region where [In] is greater than the [In] in the second region, and [Ga] is smaller than the [Ga] in the second region. The second region is the region where [Ga] is greater than the [Ga] in the first region, and [In] is smaller than the [In] in the first region.

[0397] Specifically, the first region described above is a region whose main components are indium oxide, indium zinc oxide, etc. The second region described above is a region whose main components are gallium oxide, gallium zinc oxide, etc. In other words, the first region can be rephrased as a region whose main component is In. Similarly, the second region can be rephrased as a region whose main component is Ga.

[0398] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

[0399] Furthermore, CAC-OS in In-Ga-Zn oxide refers to a material composition containing In, Ga, Zn, and O, in which regions with Ga as the main component and regions with In as the main component are arranged in a mosaic-like manner, with these regions existing randomly. Therefore, it is presumed that CAC-OS has a structure in which metal elements are unevenly distributed.

[0400] CAC-OS can be formed by sputtering, for example, under conditions where the substrate is not intentionally heated. When forming CAC-OS by sputtering, one or more gases selected from inert gases (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. Furthermore, a lower ratio of the oxygen gas flow rate to the total deposition gas flow rate during deposition is preferable. For example, it is preferable that the oxygen gas flow rate ratio to the total deposition gas flow rate during deposition be 0% or more and less than 30%, preferably 0% or more and 10% or less.

[0401] Furthermore, for example, in the case of CAC-OS in In-Ga-Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) confirms that it has a structure in which regions mainly composed of In (first region) and regions mainly composed of Ga (second region) are unevenly distributed and mixed.

[0402] Here, the first region is a region with higher conductivity compared to the second region. In other words, the conductivity of the metal oxide is exhibited when carriers flow through the first region. Therefore, a high field-effect mobility (μ) can be achieved when the first region is distributed in a cloud-like manner within the metal oxide.

[0403] On the other hand, the second region is a region with higher insulating properties compared to the first region. In other words, the distribution of the second region within the metal oxide can suppress leakage current.

[0404] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulation due to the second region work complementaryly to give CAC-OS a switching function (on / off function). In other words, CAC-OS has conductive function in some parts of the material, insulating function in other parts of the material, and semiconductor function as a whole. By separating the conductive function and the insulating function, both functions can be maximized. Thus, by using CAC-OS in a transistor, high on-current (Ion), high field-effect mobility (μ), and good switching operation can be achieved.

[0405] Furthermore, transistors using CAC-OS offer high reliability. Therefore, CAC-OS is ideal for various semiconductor devices, including display devices.

[0406] Oxide semiconductors can take on diverse structures, each possessing different properties. One embodiment of the present invention may include two or more of the following: amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0407] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0408] By using the above-mentioned oxide semiconductor in transistors, it is possible to realize transistors with high field-effect mobility. Furthermore, it is possible to realize highly reliable transistors.

[0409] It is preferable to use an oxide semiconductor with a low carrier concentration for the transistor. For example, the carrier concentration of an oxide semiconductor is 1 × 10⁻⁶. 17 cm -3 The following is preferably 1 × 10 15 cm -3 More preferably 1 × 10 13 cm -3More preferably 1 × 10 11 cm -3 More preferably 1 × 10 10 cm -3 It is less than 1 × 10 -9 cm -3 This concludes the explanation. Furthermore, when lowering the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film should be lowered to reduce the defect level density. In this specification, a low impurity concentration and low defect level density are referred to as high-purity intrinsic or substantially high-purity intrinsic. Note that oxide semiconductors with low carrier concentrations are sometimes referred to as high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors.

[0410] Furthermore, oxide semiconductor films that are highly intrinsic or substantially highly intrinsic may have a low trap level density due to their low defect level density.

[0411] Furthermore, charges trapped in the trap levels of oxide semiconductors can take a long time to disappear, sometimes behaving like fixed charges. Therefore, transistors in which channel formation regions are formed in oxide semiconductors with a high trap level density may exhibit unstable electrical properties.

[0412] Therefore, reducing the impurity concentration in the oxide semiconductor is effective in stabilizing the electrical characteristics of the transistor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in adjacent films. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon.

[0413] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0414] In oxide semiconductors, the presence of Group 14 elements, silicon or carbon, leads to the formation of defect levels within the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are compared by 2 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 17 atoms / cm 3 The following applies:

[0415] Furthermore, if an oxide semiconductor contains alkali metals or alkaline earth metals, it may form defect levels and generate carriers. Therefore, transistors using oxide semiconductors containing alkali metals or alkaline earth metals tend to exhibit normally-on characteristics. For this reason, the concentration of alkali metals or alkaline earth metals in the oxide semiconductor obtained by SIMS should be set to 1 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 16 atoms / cm 3 Do the following:

[0416] Furthermore, in oxide semiconductors, the presence of nitrogen generates electrons, which act as carriers, increasing the carrier concentration and making it easier for the semiconductor to become n-type. As a result, transistors using oxide semiconductors containing nitrogen tend to exhibit normally-on characteristics. Alternatively, the presence of nitrogen in oxide semiconductors can lead to the formation of trap levels. As a result, the electrical properties of the transistor may become unstable. For this reason, the nitrogen concentration in oxide semiconductors obtained by SIMS should be set to 5 × 10⁻⁶. 19 atoms / cm 3 Less than 5 × 10 18 atoms / cm 3 More preferably 1 × 10 18 atoms / cm 3 More preferably 5 × 10 17 atoms / cm 3 Do the following:

[0417] Furthermore, hydrogen contained in oxide semiconductors can react with oxygen bonded to metal atoms to form water, potentially creating oxygen vacancies. Hydrogen can then fill these vacancies, generating electrons, which act as carriers. Additionally, some of the hydrogen can combine with oxygen bonded to metal atoms to generate electrons. Therefore, transistors using oxide semiconductors containing hydrogen tend to exhibit normally-on characteristics. For this reason, it is preferable to reduce the hydrogen content in oxide semiconductors as much as possible. Specifically, in oxide semiconductors, the hydrogen concentration obtained by SIMS should be 1 × 10⁻⁶. 20 atoms / cm 3 Less than 1 × 10 19 atoms / cm 3 Less than 5x10 18 atoms / cm 3 Less than 1 × 10 18 atoms / cm 3 Make it less than.

[0418] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be imparted.

[0419] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0420] (Embodiment 5) In this embodiment, an electronic device according to one aspect of the present invention will be described with reference to Figures 17 to 19.

[0421] The electronic device of this embodiment has a display device according to one aspect of the present invention. The display device according to one aspect of the present invention is easily made high-definition, high-resolution, and large-scale. Therefore, the display device according to one aspect of the present invention can be used in the display units of various electronic devices.

[0422] Furthermore, since the display device according to one aspect of the present invention can be manufactured at a low cost, the manufacturing cost of electronic devices can be reduced.

[0423] Examples of electronic devices include television sets, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as other electronic devices with relatively large screens, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, and audio playback devices.

[0424] In particular, a display device according to one aspect of the present invention can be used suitably in electronic devices having a relatively small display area because it can increase resolution. Examples of such electronic devices include wearable devices that can be worn on the head, such as glasses-type AR devices and head-mounted displays for VR, as well as wearable devices such as wristwatches and bracelets. Wearable devices also include devices for SR and MR.

[0425] A display device according to one aspect of the present invention preferably has an extremely high resolution such as HD (1280 x 720 pixels), FHD (1920 x 1080 pixels), WQHD (2560 x 1440 pixels), WQXGA (2560 x 1600 pixels), 4K2K (3840 x 2160 pixels), or 8K4K (7680 x 4320 pixels). In particular, a resolution of 4K2K, 8K4K, or higher is preferred. Furthermore, the pixel density (resolution) of the display device according to one aspect of the present invention is preferably 300 ppi or more, more preferably 500 ppi or more, more preferably 1000 ppi or more, more preferably 2000 ppi or more, more preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 7000 ppi or more. By using display devices with such high resolution or high detail, it becomes possible to enhance the sense of presence and depth in personal electronic devices such as portable or home-use devices.

[0426] The electronic device of this embodiment can be incorporated along the curved surfaces of the interior or exterior walls of a house or building, or the interior or exterior of an automobile.

[0427] The electronic device in this embodiment may have an antenna. By receiving signals with the antenna, the display unit can display images and information. Furthermore, if the electronic device has an antenna and a secondary battery, the antenna may be used for contactless power transmission.

[0428] The electronic device of this embodiment may have sensors (including those with the function of measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation).

[0429] The electronic device of this embodiment can have a variety of functions. For example, it can have a function to display various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function to display a calendar, date or time, a function to execute various software (programs), a wireless communication function, a function to read programs or data recorded on a recording medium, and so on.

[0430] Figure 17A shows a perspective view of a spectacle-type electronic device 700. The electronic device 700 includes a pair of display panels 701, a pair of housings 702, a pair of optical members 703, and a pair of mounting parts 704, etc.

[0431] The electronic device 700 can project an image displayed on the display panel 701 onto the display area 706 of the optical element 703. Furthermore, because the optical element 703 is translucent, the user can view the image displayed on the display area 706 superimposed on the transmitted image seen through the optical element 703. Therefore, the electronic device 700 is an electronic device capable of AR display.

[0432] Furthermore, one of the housings 702 is equipped with a camera 705 capable of capturing images of the area in front. Although not shown, one of the housings 702 is also equipped with a wireless receiver or a connector to which a cable can be connected, allowing video signals and the like to be supplied to the housing 702. Additionally, by equipping the housing 702 with an acceleration sensor such as a gyro sensor, the orientation of the user's head can be detected and an image corresponding to that orientation can be displayed in the display area 706. Furthermore, it is preferable that the housing 702 is equipped with a battery, which can be charged wirelessly or via a wired connection.

[0433] Next, using Figure 17B, a method for projecting an image onto the display area 706 of the electronic device 700 will be described. Inside the housing 702, a display panel 701, a lens 711, and a reflector 712 are provided. In addition, the portion of the optical element 703 corresponding to the display area 706 has a reflective surface 713 that functions as a half-mirror.

[0434] Light 715 emitted from the display panel 701 passes through the lens 711 and is reflected towards the optical element 703 by the reflector 712. Inside the optical element 703, the light 715 undergoes total internal reflection repeatedly at the end face of the optical element 703 and reaches the reflective surface 713, thereby projecting an image onto the reflective surface 713. As a result, the user can see both the light 715 reflected by the reflective surface 713 and the transmitted light 716 that has passed through the optical element 703 (including the reflective surface 713).

[0435] Figure 17 shows an example where the reflector 712 and the reflective surface 713 each have curved surfaces. This increases the degree of freedom in optical design and allows for a thinner optical component 703 compared to when they are flat. However, the reflector 712 and the reflective surface 713 may also be flat.

[0436] As the reflector 712, a material having a mirror surface can be used, and it is preferable that it has a high reflectivity. Also, as the reflective surface 713, a half-mirror that utilizes the reflection of a metal film may be used, but using a prism that utilizes total internal reflection can increase the transmittance of the transmitted light 716.

[0437] Here, it is preferable that the housing 702 has a mechanism for adjusting the distance between the lens 711 and the display panel 701, or the angle between them. This makes it possible to adjust the focus, enlarge or reduce the image, etc. For example, one or both of the lens 711 or the display panel 701 may be configured to move in the optical axis direction.

[0438] Furthermore, it is preferable that the housing 702 has a mechanism that allows the angle of the reflector 712 to be adjusted. By changing the angle of the reflector 712, the position of the display area 706 on which the image is displayed can be changed. This makes it possible to position the display area 706 in an optimal position according to the user's eye position.

[0439] A display device or display module according to one aspect of the present invention can be applied to the display panel 701. Therefore, an electronic device 700 capable of displaying extremely high resolution can be created.

[0440] Figures 18A and 18B show perspective views of the goggle-type electronic device 750. Figure 18A is a perspective view showing the front, top, and left side of the electronic device 750, while Figure 18B is a perspective view showing the rear, bottom, and right side of the electronic device 750.

[0441] The electronic device 750 includes a pair of display panels 751, a housing 752, a pair of mounting parts 754, a cushioning member 755, and a pair of lenses 756, etc. The pair of display panels 751 are each provided inside the housing 752 in a position where they can be seen through the lenses 756.

[0442] The electronic device 750 is an electronic device for VR. When a user wears the electronic device 750, they can view the image displayed on the display panel 751 through the lens 756. Furthermore, by displaying different images on a pair of display panels 751, a three-dimensional display using parallax can also be performed.

[0443] Furthermore, an input terminal 757 and an output terminal 758 are provided on the rear side of the housing 752. A cable can be connected to the input terminal 757 to supply video signals from a video output device or other device, or to supply power for charging a battery located inside the housing 752. The output terminal 758 functions, for example, as an audio output terminal, and earphones, headphones, etc., can be connected to it. However, if the system is configured to output audio data via wireless communication, or if audio is output from an external video output device, the audio output terminal does not need to be provided.

[0444] Furthermore, it is preferable that the housing 752 has a mechanism that allows adjustment of the left and right positions of the lens 756 and the display panel 751 so that they are in the optimal position according to the user's eye position. It is also preferable that the housing 752 has a mechanism that adjusts the focus by changing the distance between the lens 756 and the display panel 751.

[0445] A display device or display module according to one embodiment of the present invention can be applied to the display panel 751. Therefore, an electronic device 750 capable of displaying extremely high resolution can be created. This allows the user to experience a high level of immersion.

[0446] The cushioning member 755 is the part that comes into contact with the user's face (forehead, cheeks, etc.). By ensuring that the cushioning member 755 is in close contact with the user's face, light leakage can be prevented, thereby enhancing the sense of immersion. It is preferable to use a soft material for the cushioning member 755 so that it comes into close contact with the user's face when the user wears the electronic device 750. For example, materials such as rubber, silicone rubber, urethane, and sponge can be used. Furthermore, if the surface of a sponge or similar material is covered with cloth, leather (genuine leather or synthetic leather), gaps are less likely to form between the user's face and the cushioning member 755, effectively preventing light leakage. In addition, using such materials is preferable because it feels good against the skin and does not make the user feel cold when worn in cold seasons. It is preferable that the components that come into contact with the user's skin, such as the cushioning member 755 or the mounting part 754, be removable, as this makes cleaning or replacement easier.

[0447] The electronic devices shown in Figures 19A to 19F have various functions. For example, they may have functions to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date or time, a function to control processing by various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. However, the functions of electronic devices are not limited to these and can have various functions. Electronic devices may have multiple display units. Furthermore, electronic devices may be equipped with a camera, etc., and have functions to capture still images or videos and save them to a recording medium (external or built into the camera), a function to display the captured images on a display unit, etc.

[0448] A display device according to one embodiment of the present invention can be applied to the display unit 9001.

[0449] Details of the electronic equipment shown in Figures 19A to 19F will be explained below.

[0450] Figure 19A is a perspective view showing a wristwatch-type personal information terminal 9200. The personal information terminal 9200 can be used, for example, as a smartwatch (registered trademark). The display unit 9001 has a curved display surface, allowing it to display information along the curved surface. The personal information terminal 9200 can also be used for hands-free calls by communicating with, for example, a wireless communication headset. Furthermore, the personal information terminal 9200 can transmit data to other information terminals and be charged via a connection terminal 9006. Charging may be performed by wireless power supply.

[0451] Figure 19B is a perspective view showing a personal digital assistant (PDA) 9101. The PDA 9101 can be used, for example, as a smartphone. The PDA 9101 may also be equipped with a speaker 9003, connection terminals 9006, sensors 9007, etc. The PDA 9101 can also display text and image information on multiple surfaces. Figure 19B shows an example where three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails, SNS messages, and phone calls, the subject of emails and SNS messages, sender name, date and time, battery level, and antenna signal strength. Alternatively, icons 9050 or the like may be displayed in the location where the information 9051 is displayed.

[0452] Figure 19C is a perspective view showing the personal digital assistant (PDA) 9102. The PDA 9102 has the function of displaying information on three or more sides of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, a user can check information 9053, which is displayed in a position that can be observed from above the PDA 9102, while the PDA 9102 is stored in the breast pocket of their clothing. The user can check the display without taking the PDA 9102 out of their pocket and decide, for example, whether or not to answer a call.

[0453] Figures 19D to 19F are perspective views showing a foldable personal information terminal 9201. Figure 19D shows the personal information terminal 9201 in an unfolded state, Figure 19F shows it in a folded state, and Figure 19E shows a perspective view of the state in between, transitioning from one of Figures 19D or 19F to the other. The personal information terminal 9201 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state. The display unit 9001 of the personal information terminal 9201 is supported by three housings 9000 connected by a hinge 9055. For example, the display unit 9001 can be bent with a radius of curvature of 0.1 mm to 150 mm.

[0454] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part. [Explanation of symbols]

[0455] DL_1: data line, DL_n: data line, DL_Y: data line, DL: data line, dV: potential, GL_1: gate line, GL_m: gate line, GL_X: gate line, GL: gate line, V com :Potential, V data :Second data potential, VDD:High power supply potential, V H : Potential, VL_a: Potential supply line, VL_b: Potential supply line, V L :Potential, V ref :Potential, VSS: Low power supply potential, V w -V ref :Potential difference, V w:first data potential, 100: display device, 101: substrate, 111: conductive layer, 111B: conductive layer, 111f: conductive film, 111G: conductive layer, 111R: conductive layer, 113: layer, 113B: layer, 113Bf: film, 113BF: film, 113G: layer, 113Gf: film, 113GF: film, 113 R: layer, 113Rf: film, 113RF: film, 114: layer, 114B: layer, 114f: film, 114G: layer, 114R: layer, 115: EL layer, 115a: EL layer, 115b: EL layer, 115B: EL layer, 115G: EL layer, 115R: EL layer, 116: Conductive layer, 116B: Conductive layer, 1 16f: conductive film, 116G: conductive layer, 116R: conductive layer, 117: insulating layer, 117f: insulating film, 118: insulating layer, 118a: insulating layer, 118b: insulating layer, 118f: insulating film, 120: light-emitting element, 120B: light-emitting element, 120G: light-emitting element, 120R: light-emitting element, 121: insulating layer, 131: plug, 132: structure, 133: conductive layer, 134: layer, 135: conductive layer, 137: void, 139: conductive layer, 139f: conductive film, 141B: sacrificial layer, 141BF: sacrificial film, 141G: sacrificial layer, 141GF: sacrificial film, 141R: sacrificial layer, 141RF: sacrificial film, 151B: Resist mask, 151G: Resist mask, 151R: Resist mask, 152: Resist mask, 152B: Resist mask, 152G: Resist mask, 152P: Resist mask, 152R: Resist mask, 153: Resist mask, 154: Resist mask, 161: Insulating layer, 162: Insulating layer, 163: Insulating layer, 164: Adhesive layer, 165B: Coloring layer, 165G: Coloring layer, 165R: Coloring layer, 171: Area, 172: Area, 200: Display device, 200A: Display device, 200B: Display device, 200C: Display device, 200D: Display device, 201: Base 202: Board, 210: Substrate, 211: Transistor, 212: Conductive layer, 213: Insulating layer, 214: Insulating layer, 215: Element isolation layer, 220: Transistor, 221: Semiconductor layer, 223: Insulating layer, 224: Conductive layer, 225: Conductive layer, 226: Insulating layer, 227: Conductive layer, 228: Insulating layer, 229: Insulating layer, 230: Transistor, 231: Insulating layer, 232: Insulating layer, 240: Capacitive element, 241: Conductive layer, 242: Conductive layer, 243: Insulating layer, 251: Conductive layer, 252: Conductive layer, 253: Conductive layer, 261: Insulating layer, 261a: Insulating layer, 261b: Insulating layer,262: Insulating layer, 263: Insulating layer, 264: Insulating layer, 265: Insulating layer, 271: Plug, 271a: Conductive layer, 271b: Conductive layer, 272: Plug, 273: Plug, 274: Plug, 280: Display module, 281: Display unit, 282: Circuit unit, 283: Pixel circuit unit, 283a: Pixel circuit, 284: Pixel unit, 284a: Pixel, 285: Terminal unit, 286: Wiring unit, 290: FPC, 400: Pixel circuit 400EL: Pixel circuit, 401: Circuit, 401EL: Circuit, 501: Pixel circuit, 502: Pixel section, 504: Drive circuit section, 504a: Gate driver, 504b: Source driver, 506: Protection circuit, 507: Terminal section, 552: Transistor, 554: Transistor, 562: Capacitive element, 572: Light-emitting element, 700: Electronic equipment, 701: Display panel, 702: Housing, 703: Optical component, 704: Mounting Part, 705: Camera, 706: Display area, 711: Lens, 712: Reflector, 713: Reflective surface, 715: Light, 716: Transmitted light, 750: Electronic equipment, 751: Display panel, 752: Housing, 754: Mounting part, 755: Cushioning material, 756: Lens, 757: Input terminal, 758: Output terminal, 4411: Light-emitting layer, 4412: Light-emitting layer, 4413: Light-emitting layer, 4420: Layer, 4420-1: Layer, 4420-2: Layer, 4430: Layer, 4430-1: Layer, 4430-2: Layer, 4440: Intermediate layer, 9000: Enclosure, 9001: Display unit, 9003: Speaker, 9006: Connection terminal, 9007: Sensor, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9101: Personal digital assistant, 9102: Personal digital assistant, 9200: Personal digital assistant, 9201: Personal digital assistant,

Claims

[Claim 1] The first insulating layer, On the first insulating layer, a light-emitting element and a first conductive layer, The first conductive layer and the first layer on the first conductive layer, A second conductive layer on the first layer, A third conductive layer on the light-emitting element and on the second conductive layer, It has, The light-emitting element is A fourth conductive layer, The second layer on the fourth conductive layer, The third layer on the aforementioned second layer, A fifth conductive layer on the third layer, It has, The third conductive layer has a region in contact with the second conductive layer and a region in contact with the fifth conductive layer. The second layer comprises a luminescent compound, The first conductive layer and the fourth conductive layer contain the same material. The first layer and the third layer contain the same material. A display device comprising the second conductive layer and the fifth conductive layer, each containing the same material.

Images