Display device and electronic apparatus

Abstract

Provided is a display device that is suited to combination with a solar cell. According to the present invention, a display device that is suited to combination with a solar cell has subpixels and a light-transmitting region and also has a light-transmitting insulator that eliminates a level difference from the subpixels to the light-transmitting region. The insulator has a curved surface in a region near an end part, and said region can be made to act as a lens. As a result, light that enters the display device from the outside can be refracted to enter the light-transmitting region, making it possible for comparatively more light to be transmitted. An electronic apparatus that includes the display device and a solar cell that is provided on a back surface side of the display device allows more light to enter the solar cell and makes it possible to generate more power.

Description

Display devices and electronic devices

[0001] One embodiment of the present invention relates to a display device and an electronic device.

[0002] One embodiment of the present invention is not limited to the above technical field, and examples of the technical field of one embodiment of the present invention include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device (for example, a touch sensor), an input / output device (for example, a touch panel), a power generation device, a driving method thereof, or a manufacturing method thereof.

[0003] Portable devices such as smartphones and tablet computers are equipped with secondary batteries as power sources. Users can operate the devices by charging the secondary batteries. The charging interval varies depending on the type of device and the length of time it is used, but the longer the charging interval, the more convenient it is for users.

[0004] To extend the charging span, it is effective to reduce the power consumption of the device and increase the capacity of the secondary battery, and development efforts are being made in each field. There are also attempts to assist the charging of secondary batteries by generating electricity using natural energy. For example, Patent Document 1 discloses an EL display device with a solar cell panel, in which a solar cell panel is arranged on the backside of a transparent EL (electroluminescence) panel.

[0005] JP 2014-115526 A

[0006] The transparent EL panel disclosed in Patent Document 1 is a passive matrix type that uses transparent conductive films as electrodes on both sides of the EL element, allowing a relatively large amount of light to pass through the pixels and reach the solar cell. However, passive matrix types are prone to crosstalk and emit light in a line-sequential manner, making them unsuitable for high-speed operation such as video display and for application to high-resolution panels. Furthermore, because the light emitted by the EL element in a transparent EL panel is emitted in both directions, even if some of the light can be used for power generation, the brightness on the side viewed by the user is insufficient.

[0007] Therefore, an object of one embodiment of the present invention is to provide a display device that is suitable for combination with a solar cell. Another object is to provide an electronic device that includes a display device and a power generation device with high display quality. Another object is to provide an electronic device that can be charged using natural energy. Another object is to provide an electronic device that requires low charging frequency.

[0008] Note that the description of these problems does not preclude the existence of other problems. One embodiment of the present invention does not necessarily have to solve all of these problems. Problems other than these can be extracted from the description in the specification, drawings, and claims.

[0009] One embodiment of the present invention relates to a display device suitable for combination with a solar cell, and an electronic device including the display device and a power generation device.

[0010] One embodiment of the present invention is a display device that includes a pixel having a subpixel and a light-transmitting region, the light-transmitting region being adjacent to the subpixel and having a function of transmitting light incident from outside, the subpixel having a light-emitting device in which a pixel electrode, a light-emitting layer, and a common electrode are stacked, the subpixel and the light-transmitting region having an insulating layer that is transparent to visible light, an end of the insulating layer being located above the pixel electrode, the insulating layer having a curved surface from the end to the light-transmitting region, and an optical path in which light incident on the subpixel is incident on the light-transmitting region via the curved surface.

[0011] The light-emitting layer can emit either red, green, or blue light.

[0012] It is preferable that the pixel electrode is reflective to visible light, and the common electrode is translucent to visible light.

[0013] Another embodiment of the present invention is an electronic device including the above display device and a solar cell in which a plurality of cells are connected in series, the solar cell being disposed on the back surface side of the display device.

[0014] Another embodiment of the present invention is an electronic device including a display device and a solar cell in which a plurality of cells are connected in series, the solar cell being disposed on a back surface side of the display device. The display device includes a pixel including a first subpixel and a second subpixel, the first subpixel including a first light-emitting device having a first pixel electrode, a first light-emitting layer, and a common electrode, the second subpixel including a second light-emitting device having a second pixel electrode, a second light-emitting layer, and a common electrode, the first pixel electrode being reflective to visible light, the second pixel electrode and the common electrode being transparent to visible light, the first light-emitting layer and the second light-emitting layer each emitting white light, and a color filter being provided over the first light-emitting device.

[0015] The solar cell has a photoelectric conversion layer, and the photoelectric conversion layer preferably contains perovskite crystals.

[0016] The electronic device has a camera module with a lens, and one cell of the solar cell has an opening, and the opening and the lens can be arranged to overlap.

[0017] In a wristwatch-type electronic device in which the above-mentioned display device and solar cell are housed in a housing, the housing has a configuration in which multiple cells are lined up in one direction, the housing has a first region and a second region opposite the first region, a band can be connected to the first region and the second region, and it is preferable that the direction in which the first region and the second region are lined up is the same as the direction in which the multiple cells are lined up.

[0018] According to one embodiment of the present invention, a display device suitable for combination with a solar cell can be provided. Alternatively, an electronic device including a display device and a power generation device with high display quality can be provided. Alternatively, an electronic device that can be charged using natural energy can be provided. Alternatively, an electronic device that requires infrequent charging can be provided.

[0019] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims.

[0020] FIG. 1 is a perspective view illustrating a portion of an electronic device. FIG. 2 is a block diagram illustrating a power supply system of an electronic device. FIGS. 3A and 3B are diagrams illustrating pixels. FIG. 4 is a diagram illustrating pixels. FIGS. 5A and 5B are diagrams illustrating pixels. FIGS. 6A to 6D are diagrams illustrating pixels. FIGS. 7A and 7B are block diagrams illustrating a display device. FIGS. 7C and 7D are diagrams illustrating pixel circuits. FIGS. 8A and 8B are diagrams illustrating an electronic device. FIGS. 9A to 9D are diagrams illustrating an electronic device. FIGS. 10A and 10B are diagrams illustrating an electronic device. FIGS. 11A to 11D are diagrams illustrating a solar cell. FIGS. 12A to 12C are diagrams illustrating a solar cell. FIG. 13A is a cross-sectional view illustrating an example of a display device. FIGS. 13B and 13C are cross-sectional views illustrating an example of a transistor. FIGS. 14A and 14B are diagrams illustrating an example of a transistor.

[0021] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and those skilled in the art will readily understand that various modifications in form and detail may be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below. In the configuration of the invention described below, the same parts or parts having similar functions will be designated by the same reference numerals in different drawings, and repeated description thereof may be omitted. Hatching of the same elements constituting the drawings may be omitted or changed as appropriate in different drawings.

[0022] Furthermore, even if a circuit diagram shows a single element, that element may be configured as multiple elements as long as there is no functional problem. For example, multiple transistors operating as switches may be connected in series or parallel. Also, a capacitor may be divided and placed in multiple locations.

[0023] Furthermore, one conductor may have multiple functions, such as wiring, electrode, and terminal, and in this specification, multiple names may be used for the same element. Also, even when elements are shown as being directly connected to each other on a circuit diagram, in reality, the elements may be connected via one or more conductors, and in this specification, such a configuration is also included in the category of direct connection.

[0024] In this specification, "connection" includes, as an example, "electrical connection." Note that the term "electrical connection" is sometimes used to define the connection relationship between circuit elements as an object. Furthermore, "electrical connection" includes "direct connection" and "indirect connection." "A and B are directly connected" means that A and B are connected without the intervention of a circuit element (e.g., a transistor, a switch, etc.; note that wiring is not a circuit element). On the other hand, "A and B are indirectly connected" means that A and B are connected via one or more circuit elements. Note that A, B, and C, which will be described later, represent objects such as elements, circuits, wiring, electrodes, terminals, semiconductor layers, and conductive layers.

[0025] For example, assuming that a circuit including A and B is operating, if there is a time during the operation of the circuit when an electrical signal is exchanged or an interaction of electrical potential occurs between A and B, then it can be defined that "A and B are indirectly connected" as objects. Note that even if there is a time during the operation of the circuit when no electrical signal is exchanged or an interaction of electrical potential occurs between A and B, it can still be defined that "A and B are indirectly connected" as long as there is a time during the operation of the circuit when an electrical signal is exchanged or an interaction of electrical potential occurs between A and B.

[0026] An example of a case where "A and B are indirectly connected" is when A and B are connected via the source and drain of one or more transistors. On the other hand, an example of a case where it cannot be said that "A and B are indirectly connected" is when an insulator is present in the path from A to B. Specifically, there are cases where a capacitive element is connected between A and B, and cases where a gate insulating film of a transistor is present between A and B. Therefore, it cannot be said that "the gate (A) of a transistor and the source or drain (B) of the transistor are indirectly connected."

[0027] Another example of a case where it cannot be said that "A and B are indirectly connected" is when multiple transistors are connected via their sources and drains to the path from A to B, and a constant potential V is supplied to a node between one transistor and another transistor from a power supply, GND, etc.

[0028] Embodiment 1 In this embodiment, a display device and an electronic device according to one embodiment of the present invention will be described with reference to drawings.

[0029] One embodiment of the present invention is a display device and an electronic device including the display device, a solar cell, and a secondary battery. The display device is an active matrix light-emitting device having a light-transmitting region. The electronic device includes a solar cell on a back surface side opposite to a display surface of the light-emitting device, and a secondary battery on a back surface side opposite to a light-receiving surface of the solar cell.

[0030] A display device according to one embodiment of the present invention includes first to third subpixels that emit red (R), green (G), and blue (B) light, respectively, and a light-transmitting region in one pixel. Note that the light-transmitting region can also be a fourth subpixel that emits white (W) light and has light-transmitting properties.

[0031] The display device also includes a light-transmitting insulator that eliminates steps between subpixels and between the subpixels and the light-transmitting region. A curved surface is provided in a region near the edge of the insulator, allowing the region to function as a lens. Therefore, light incident on the display device from the outside can be refracted and made to enter the light-transmitting region, allowing the display device to transmit a relatively large amount of light. This means that a large amount of light can reach the solar cell located on the back side of the display device, thereby increasing the amount of power generation.

[0032] The display device is an active matrix type, capable of full color, high resolution, and high-speed operation. Furthermore, the power generated by the solar cell can be stored in a secondary battery, which can then supply power to the display device and other devices in the electronic device. Therefore, since a portion of the power consumed by the electronic device can be generated by the solar cell, the charging interval for the user can be extended, improving convenience. Furthermore, depending on the type of electronic device, all operations can be performed using the power generated by the solar cell.

[0033] 1 is a perspective view illustrating an electronic device of one embodiment of the present invention, and illustrates a part of a display device 40, a solar cell 30, a circuit portion 21, and a secondary battery 22 included in the electronic device. In addition, some elements are cut away in the perspective view, and an enlarged view of a pixel 10 included in the display device 40 is shown in the upper right corner of the perspective view.

[0034] The display device 40 has pixels 10 between a pair of light-transmitting substrates. For clarity, in Fig. 1, the substrate on the display surface side of the pair of substrates is indicated by a dashed line.

[0035] The pixel 10 has a sub-pixel R that emits red light (for example, a wavelength of 625 nm to 780 nm), a sub-pixel G that emits green light (for example, a wavelength of 500 nm to 565 nm), a sub-pixel B that emits blue light (for example, a wavelength of 450 nm to 485 nm), and a light-transmitting region T. Note that within the pixel 10, the positions of the sub-pixels and the light-transmitting region T can be interchanged as appropriate.

[0036] A full-color display is possible by providing sub-pixels R, G, and B corresponding to the three primary colors of light (R, G, and B) in the pixel 10. Furthermore, the provision of the light-transmitting region T enables the solar cell 30 provided on the back side of the display device 40 (the surface opposite the display surface) to generate electricity.

[0037] In the display device 40, the provision of the light-transmitting region T in the pixel 10 reduces the area occupied by the sub-pixels, making it difficult to increase brightness. On the other hand, light incident on the light-transmitting region T from the outside is absorbed by the solar cell 30, reducing the amount of reflected light in the entire display area and improving the display contrast. This makes it possible to omit an anti-reflection layer such as a circular polarizer, thereby compensating for the reduction in brightness caused by the reduced area occupied by the sub-pixels. Because the transmittance of a circular polarizer is at most about 50%, omitting the circular polarizer is also effective in power generation in the solar cell 30.

[0038] The solar cell 30 is disposed on the rear side of the display device, and is capable of generating electricity by irradiating the display surface of the display device 40 from the outside and transmitting light through the light-transmitting region T. Although Fig. 1 illustrates a configuration in which the display device 40 and the solar cell 30 are in contact with each other, they may also be spaced apart.

[0039] The electronic device of one embodiment of the present invention is a portable terminal or a small, easily portable terminal intended for indoor and outdoor use. Therefore, the photoelectric conversion layer of the solar cell 30 preferably has high sensitivity to visible light so that it can generate power even from indoor electric lights, etc. Furthermore, the solar cell 30 is preferably thin so that it can be housed within the housing of the electronic device, and is preferably easily integrated so that it generates the voltage required to charge the secondary battery 22.

[0040] Therefore, the solar cell 30 is made of amorphous silicon and CIS (CuInSe) ２ ), CIGS(Cu(In,Ga)Se ２ ), Cu ２ Preferably, the solar cell 30 is a thin-film solar cell using a perovskite crystal or a perovskite crystal. Alternatively, the solar cell 30 may be a tandem thin-film solar cell in which two or more of these are stacked. Details of the solar cell 30 will be described later in other embodiments.

[0041] The circuit unit 21 and the secondary battery 22 are provided on the back side of the solar cell 30. Although Fig. 1 illustrates a configuration in which the solar cell 30, the circuit unit 21, and the secondary battery 22 are in contact with each other, they may be separated from each other. Furthermore, the circuit unit 21 and the secondary battery 22 may be provided so as to have an overlapping region with each other.

[0042] The circuit section 21 has a plurality of IC chips, discrete semiconductors, input / output terminals, wiring, etc. mounted on a PCB (Printed Circuit Board) or FPC (Flexible Printed Circuits), and is a part for controlling the entire electronic device, including controlling the charging and discharging of the secondary battery 22, and supplying power.

[0043] The secondary battery 22 is a rechargeable battery, and may be, for example, a lithium ion battery, a sodium ion battery, a lithium sulfur battery, or a coin-type lithium ion secondary battery. Alternatively, a nickel-metal hydride battery, a lead-acid battery, a semi-solid battery, an all-solid battery, or an electric double layer capacitor may also be used. Alternatively, two or more of these may be used in combination.

[0044] 2 is a block diagram illustrating a power supply system in an electronic device 50 according to one embodiment of the present invention. In FIG. 2 , an external power source 60 such as a commercial power source is shown outside the frame of the electronic device 50. Depending on the functions of the electronic device, a small electronic device such as a smart watch (registered trademark) may be able to be driven only by power supply from a solar cell. In this case, the charging function using the external power source 60 may be omitted from the electronic device 50.

[0045] On the other hand, electronic devices such as smartphones have various functions such as communication, display, and information processing, and consume relatively high power consumption. Therefore, in the electronic device 50, charging by the external power source 60 is the main method, and charging by the solar cell 30 is secondary.

[0046] Power supplied from the solar cell 30 or the external power supply 60 is supplied to the secondary battery 22 via the circuit unit 21 and stored therein. The circuit unit 21 receives power from the secondary battery 22 and can perform voltage conversion so that the secondary battery 22 is appropriately charged. Alternatively, the circuit unit 21 can perform control such as pulse charging. The power stored in the secondary battery 22 can be supplied to the display device 40 and the like.

[0047] Next, details of the pixel 10 included in the display device 40 will be described. The display device of one embodiment of the present invention is a top-emission type that emits light in a direction opposite to a substrate on which a light-emitting device (also referred to as a light-emitting element) is formed.

[0048] 3A is a top view of pixel 10. As described above, pixel 10 has subpixels R, G, and B, and light-transmitting region T. Light-transmitting region T may have or not have a light-emitting device. First, an example in which light-transmitting region T has no light-emitting device (light-transmitting region T1) will be described.

[0049] In the following description, a cross-sectional view will be used to describe the subpixel B and the light-transmitting region T1 of the pixel 10. Note that the subpixels R and G of the pixel 10 can share the same components as the subpixel B, except for a portion of the EL layer such as the light-emitting layer, and therefore descriptions thereof will be omitted.

[0050] FIG. 3B shows a cross-sectional view of the subpixel B and the light-transmitting region T1 of the pixel 10 shown in FIG. 3A, and a cross-sectional view of the subpixel B between X1 and X2 of an adjacent pixel 10. In FIG.

[0051] 3B , an insulating layer (insulating layers 255a, 255b, and 255c) is provided on the layer 101, and in subpixel B, a light-emitting device 130b is provided on the insulating layer. A protective layer 131 is provided to cover the light-emitting device 130b. Note that the layer 101 can be a layer including transistors and the like that constitute a pixel circuit and a light-transmitting supporting substrate, and the cross section shown in FIG. 3B shows a region where no transistors and the like are provided.

[0052] The solar cell 30 can be disposed below the layer 101. Although Fig. 3B shows an example in which the solar cell 30 is disposed apart from the layer 101, the two may have an area in which they are in contact with each other. An adhesive that is translucent to visible light may be provided between the solar cell 30 and the layer 101.

[0053] A light-shielding layer 135 and a substrate 120 are bonded to the protective layer 131 via an adhesive layer 122. The light-shielding layer 135 is provided between one adjacent subpixel and the other adjacent subpixel or light-transmitting region T1. The use of the light-shielding layer 135 can suppress light leakage (stray light) into adjacent subpixels, thereby improving the display quality of the display device. The substrate 120 is a light-transmitting support substrate.

[0054] The layer 101 can have a stacked structure including a plurality of transistors provided on a substrate and an insulating layer covering these transistors. The insulating layer on the transistor is not limited to a single-layer structure, and can also have a stacked structure. Figure 3B shows a stack of insulating layers 255a, 255b, and 255c among the insulating layers on the transistor. The reliability of the transistor can be improved by using a stacked structure for the insulating layer on the transistor.

[0055] The insulating layers 255a, 255b, and 255c can be formed using various inorganic insulating films such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film. The insulating layers 255a and 255c are preferably formed using an oxide insulating film or an oxynitride insulating film such as a silicon oxide film, a silicon oxynitride film, or an aluminum oxide film. The insulating layer 255b is preferably formed using a nitride insulating film or a nitride oxide insulating film such as a silicon nitride film or a silicon nitride oxide film. More specifically, the insulating layers 255a and 255c are preferably formed using silicon oxide films, and the insulating layer 255b is preferably formed using a silicon nitride film. The insulating layer 255b preferably functions as an etching protective film.

[0056] In this specification and the like, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0057] As the light-emitting device, it is preferable to use an OLED (organic light-emitting diode) or a QLED (quantum-dot light-emitting diode). Examples of light-emitting materials that the light-emitting device has include fluorescent materials (fluorescent materials), phosphorescent materials (phosphorescent materials), and materials that exhibit thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) materials). As the light-emitting material that the EL element has, not only organic compounds but also inorganic compounds (such as quantum dot materials) can be used. Furthermore, LEDs such as micro LEDs (light-emitting diodes) can also be used as the light-emitting device.

[0058] A light-emitting device that can be used in one embodiment of the present invention preferably uses an MML (metal maskless) structure in which light-emitting layers are separately formed using a lithography process without using a FMM (fine metal mask). A light-emitting device with an MML structure can have a higher aperture ratio than a light-emitting device fabricated using an FMM, and can emit light with higher luminance or lower power consumption. Furthermore, since light-emitting layers with different emission colors can be formed for each subpixel, a color filter is not required, and the luminance of the display device can be increased.

[0059] One of the pair of electrodes in a light-emitting device functions as a cathode and the other as an anode. For example, the pixel electrode can function as the anode and the common electrode can function as the cathode.

[0060] The light-emitting device 130b includes a pixel electrode 111b, an island-shaped layer 113b, a common layer 114, and a common electrode 117. The light-emitting device 130b emits light L Ｂ Since the light-emitting device 130b is a top-emission type that emits visible light, the pixel electrode 111b can be formed of a material that is reflective to visible light, and is preferably a metal layer with high reflectivity. The layer 113b contains a light-emitting organic compound (light-emitting layer) that emits at least blue light. In the light-emitting device 130b, the layer 113b and the common layer 114 can be collectively referred to as an EL layer.

[0061] The layer 113b can be processed into an island shape using, for example, a resist mask formed by lithography. By providing the layer 113b in an island shape for each light-emitting device, leakage current between adjacent light-emitting devices can be suppressed. This makes it possible to prevent light emission due to unintended crosstalk and realize a display device with extremely high contrast. In particular, a display device with high current efficiency at low luminance can be realized.

[0062] The layer 113b and the common layer 114 can each independently include one or more of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. For example, the layer 113b can have a stacked structure of a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer from the pixel electrode 111b side, and the common layer 114 can have an electron injection layer.

[0063] The light-emitting device of this embodiment may also have a tandem structure. In the case of a light-emitting device with a tandem structure, the layer 113b may have two or more light-emitting units, each of which may include one or more light-emitting layers. Each light-emitting unit may have one or more of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer. A charge generation layer is preferably provided between each light-emitting unit. The charge generation layer has at least a charge generation region.

[0064] For example, the layer 113b can have a stacked structure of a light-emitting unit 113_1, a charge generation layer 113_3, and a light-emitting unit 113_2 (see an enlarged view of the layer 113b in FIG. 4). Note that in the drawings used in this embodiment, the charge generation layer may be indicated by a dashed line.

[0065] Tandem light-emitting devices, which emit light from multiple light-emitting units, require a relatively high voltage to emit light, but require a smaller current to achieve the same emission intensity as a single-type light-emitting device (one light-emitting unit configuration). Therefore, the tandem structure can reduce the current stress per light-emitting unit and extend the device life. In other words, the use of tandem light-emitting devices can form highly reliable display devices.

[0066] In the structure shown in FIG. 4 , the light-emitting unit 113_2 preferably includes a light-emitting layer and a carrier transport layer (electron transport layer or hole transport layer) on the light-emitting layer. Alternatively, the light-emitting unit 113_2 preferably includes a light-emitting layer and a carrier block layer (hole block layer or electron block layer) on the light-emitting layer. Alternatively, the light-emitting unit 113_2 preferably includes a light-emitting layer, a carrier block layer on the light-emitting layer, and a carrier transport layer on the carrier block layer. Since the surface of the light-emitting unit 113_2 is exposed during the manufacturing process of the display device, providing one or both of a carrier transport layer and a carrier block layer on the light-emitting layer can prevent the light-emitting layer from being exposed to the outermost surface and reduce damage to the light-emitting layer. This can improve the reliability of the light-emitting device. Note that when three or more light-emitting units are included, the uppermost light-emitting unit preferably includes a light-emitting layer and one or both of a carrier transport layer and a carrier block layer on the light-emitting layer.

[0067] The common layer 114 may have an electron injection layer or a hole injection layer. Alternatively, the common layer 114 may have a stack of an electron transport layer and an electron injection layer. Alternatively, the common layer 114 may have a stack of a hole transport layer and a hole injection layer. The common layer 114 and the common electrode 117 are shared by the light-emitting devices of each sub-pixel.

[0068] 3B, layer 113b is formed to cover the edge of pixel electrode 111b. Furthermore, mask layer 118 is located on layer 113b of light-emitting device 130b. Mask layer 118 is a part of a mask layer provided in contact with the upper surface of layer 113b when processing layer 113b.

[0069] An insulating layer 125 and an insulating layer 127 on the insulating layer 125 are provided between the subpixels and from the subpixels to the light-transmitting region. Although the display device 40 has steps due to the pixel electrodes and the like, providing the insulating layers 125 and 127 makes the surface curved or flat, thereby eliminating the effects of the steps. This improves the coverage of the common layer 114 and common electrode 117 provided on the layer 113b, thereby preventing connection failures due to step disconnections. Furthermore, it is possible to prevent the common electrode 117 from becoming locally thin due to the steps, thereby preventing an increase in electrical resistance.

[0070] Therefore, between the light-emitting devices, it is possible to prevent poor connection due to the disconnection of the common layer 114 and the common electrode 117 and an increase in electrical resistance due to a locally thin portion of the film thickness in the common layer 114 and the common electrode 117. As a result, the display device according to one embodiment of the present invention can improve the display quality.

[0071] Next, we will explain examples of materials for the insulating layer 125 and the insulating layer 127. Note that the insulating layer 125 and the insulating layer 127 are preferably highly translucent because they are provided in the optical path through which light irradiated onto the display device 40 from the outside reaches the solar cell 30.

[0072] The insulating layer 125 can be an insulating layer containing an inorganic material. For example, an inorganic insulating film such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film can be used for the insulating layer 125. The insulating layer 125 is not limited to a single-layer structure, but can also have a stacked structure. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, magnesium oxide films, indium gallium zinc oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxynitride insulating films include silicon oxynitride films and aluminum oxynitride films. Examples of nitride oxide insulating films include silicon nitride oxide films and aluminum nitride oxide films. Aluminum oxide is particularly preferable because it has a high etching selectivity with respect to the EL layer and functions to protect the EL layer in the formation of the insulating layer 127, which will be described later.

[0073] In particular, by using an inorganic insulating film such as an aluminum oxide film, a hafnium oxide film, or a silicon oxide film formed by atomic layer deposition (ALD) as the insulating layer 125, it is possible to form an insulating layer 125 that has few pinholes and has an excellent function of protecting the EL layer. The insulating layer 125 can also have a stacked structure of a film formed by ALD and a film formed by sputtering. For example, the insulating layer 125 can have a stacked structure of an aluminum oxide film formed by ALD and a silicon nitride film formed by sputtering.

[0074] The insulating layer 125 preferably functions as a barrier insulating layer against at least one of water and oxygen. The insulating layer 125 preferably has a function of suppressing diffusion of at least one of water and oxygen. The insulating layer 125 preferably has a function of capturing or fixing (also referred to as gettering) at least one of water and oxygen.

[0075] In this specification and the like, a barrier insulating layer refers to an insulating layer having barrier properties. In addition, in this specification and the like, the barrier properties refer to a function of suppressing the diffusion of a corresponding substance (also referred to as low permeability) or a function of capturing or fixing (also referred to as gettering) a corresponding substance.

[0076] The insulating layer 125 has a function as a barrier insulating layer or a gettering function, which makes it possible to suppress the intrusion of impurities (typically, at least one of water and oxygen) that may diffuse into each light-emitting device from the outside. With this configuration, it is possible to provide a highly reliable light-emitting device and further a highly reliable display device.

[0077] The same material can be used for the insulating layer 125 and the mask layer 118. In this case, the boundary between the mask layer 118 and the insulating layer 125 becomes unclear, and the mask layer 118 and the insulating layer 125 may be recognized as a single layer.

[0078] An insulating layer containing an organic material can be suitably used as the insulating layer 127. As the organic material, a photosensitive organic resin is preferably used, for example, a photosensitive resin composition containing an acrylic resin. Note that in this specification and the like, the term "acrylic resin" does not refer only to polymethacrylic acid ester or methacrylic resin, but may refer to all acrylic polymers in a broad sense.

[0079] The insulating layer 127 can be made of acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin, or precursors of these resins. The insulating layer 127 can be made of organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin. The photosensitive organic resin can be a photoresist. Both positive-type and negative-type materials can be used as the photosensitive organic resin.

[0080] The adhesive layer 122 can be made of various curable adhesives, such as a photo-curable adhesive (e.g., an ultraviolet curable adhesive), a reactive curable adhesive, a thermosetting adhesive, or an anaerobic adhesive. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. In particular, a material with low moisture permeability, such as epoxy resin, is preferable. A two-component resin can also be used. An adhesive sheet or the like can also be used.

[0081] The substrate 120 and the supporting substrate of the layer 101 can be made of glass, quartz, ceramics, sapphire, resin, metal, alloy, semiconductor, or the like. A material that transmits light is used for the substrate on the side from which light from the light-emitting device is extracted. Using a flexible material for the substrate can increase the flexibility of the display device.

[0082] For example, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, and cellulose nanofiber can be used. Furthermore, glass having a thickness sufficient to provide flexibility can be used as the substrate having Tadashi Kato.

[0083] The absolute value of the retardation (phase difference) of a substrate having high optical isotropy is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0084] Examples of films with high optical isotropy include triacetyl cellulose (TAC, also known as cellulose triacetate) films, cycloolefin polymer (COP) films, cycloolefin copolymer (COC) films, and acrylic resin films.

[0085] Furthermore, when a film is used as a substrate, the film may absorb water, causing deformation such as wrinkles in the display device. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferably 0.1% or less, and even more preferably 0.01% or less.

[0086] Various optical members may be disposed on the outside of the substrate 120. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light-collecting film. Furthermore, on the outside of the substrate 120, a surface protection layer such as an antistatic film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses scratches that occur during use, or an impact absorbing layer may also be disposed.

[0087] As the surface protective layer, a glass layer or a silica layer (SiO ｘ The surface protection layer can be preferably formed of a material such as DLC (diamond-like carbon), aluminum oxide (AlO ｘ ), polyester-based materials, or polycarbonate-based materials may also be used. Note that it is preferable to use a material with high transmittance to visible light for the surface protection layer. It is also preferable to use a material with high hardness for the surface protection layer.

[0088] The light-transmitting region T1 is configured to be free of other components of the light-emitting device except for the common layer 114 and the common electrode 117, and can be configured to have a laminate of insulating layers 125 and 127 whose ends are located above the pixel electrodes of the subpixels. That is, the vicinity of the center of the light-transmitting region T1 can be configured to have a laminate of insulating layers 255c, 255b, 255a, 125, 127, the common layer 114, the common electrode 117, and the protective layer 131, as shown in FIG. 3B .

[0089] In order to increase the amount of power generated by the solar cell 30, it is preferable that all elements of the above-described stacked structure in the light-transmitting region T1 be formed from materials that have high transmittance to visible light or light with wavelengths ranging from blue light to red light. In addition, in order to increase the transmittance of the light-transmitting region T1, a structure in which one or more of the insulating layer 255a, the insulating layer 255b, the insulating layer 255c, the common layer 114, the common electrode 117, and the protective layer 131 are not provided may be used.

[0090] As shown in FIG. 3B, light L irradiated onto the display device 40 from the outside Ｏ Of the light reaching the solar cell 30, not only does the light directly enter the light-transmitting region T1, but also light that passes through the sub-pixels adjacent to the light-transmitting region T1. This is because the insulating layer 127, which is provided to eliminate the step, has a convex lens-like curved surface from the end to the light-transmitting region T1, so that light that enters the end of the insulating layer 127 and the layer formed on its upper surface in the sub-pixel is refracted, changing the direction of travel of the light. This allows more light to enter the solar cell, increasing the amount of power generation.

[0091] Furthermore, light L emitted by the light-emitting device 130b and reflected at interfaces and the like in the structure of the display device 40 Ｒｅｆ The lens effect of the end of the insulating layer 127 allows the reflected light to reach the solar cell 30 through the light-transmitting region T1. In a typical display device, much of the reflected light generated at the interface of the structure is absorbed by elements within the display device and is lost without being extracted to the display surface side. In one aspect of the present invention, even if the reflected light generated at the interface of the structure is not extracted to the display surface side, it can be used for power generation by the solar cell.

[0092] Next, an example will be described in which the light-transmitting region T has a light-emitting device (light-transmitting region T2). The pixel 10 having the light-transmitting region T2 can also be configured using the MML structure described above, allowing light-emitting devices with different emission colors to be formed for each subpixel. Producing different EL layers with different emission colors for each of the four subpixels can improve display quality.

[0093] On the other hand, if the light-emitting devices of all the sub-pixels are configured to emit white light and color filters are provided so that each sub-pixel emits a different color, the manufacturing process can be simplified. Therefore, an example in which the light-emitting devices of all the sub-pixels emit white light will be described here.

[0094] 5A is a top view of a pixel 10 having a light-transmitting region T2, and FIG. 5B is a cross-sectional view of adjacent subpixel B, light-transmitting region T2, and X3-X4 in subpixel B shown in FIG. 5A.

[0095] 3A and 3B in that layer 113b contains a light-emitting organic compound (light-emitting layer) that emits at least white light, and that color filter 137 that transmits blue light is provided between substrate 120 and adhesive layer 122.

[0096] Furthermore, the light-transmitting region T2 differs from the light-transmitting region T1 in that a light-emitting device 130w is provided therein, and the light-transmitting region T2 can also be called a sub-pixel. The light-emitting device 130w can be configured to emit white light. In the following description, a sub-pixel that emits white light (W) may be called a sub-pixel W. A color filter is not required for the sub-pixel W.

[0097] Here, the effect of the sub-pixel W will be explained. Basically, a full-color display is possible by providing a pixel with sub-pixels R, G, and B, which correspond to the three primary colors of light (R, G, and B). However, by adding the sub-pixel W, power consumption can be reduced and brightness can be increased.

[0098] For example, when displaying white, power consumption can be reduced by driving one subpixel W rather than driving three subpixels, subpixels R, G, and B, to emit white light. In particular, when the light emitted from the EL layer is white light and color filters are used for the subpixels R, G, and B, the attenuation of the light amount is large. Therefore, the effect of driving the subpixel W without using a color filter is significant.

[0099] Furthermore, since white light can be said to contain red, green, and blue light components, the color created by red, green, and blue light can also be created by white light and one or two of red, green, and blue light. Therefore, depending on the color to be created, the number of sub-pixels to be driven can be reduced, thereby reducing power consumption.

[0100] Furthermore, because white light is a substitute for red light, green light, and blue light, causing subpixel W to emit light is equivalent to causing all of subpixels R, G, and B to emit light. Therefore, causing the four subpixels R, G, B, and W to emit light can increase the display brightness.

[0101] In this way, by providing the pixel 10 with four sub-pixels, sub-pixel R, sub-pixel G, sub-pixel B, and sub-pixel W, it is possible to reduce power consumption and increase brightness.

[0102] The light-emitting device 130 w includes a pixel electrode 111 w, an island layer 113 w, a common layer 114 , and a common electrode 117 .

[0103] In order to emit white light, the layers 113b and 113w preferably have a tandem structure in which light-emitting units of different light-emitting colors are combined. To obtain white light emission, a configuration is used in which light emitted by a plurality of light-emitting units is combined to obtain white light emission. For example, in the configuration shown in FIG. 4 , one of the light-emitting units 113_1 and 113_2 is a blue-emitting unit, and the other is a yellow-emitting unit. Alternatively, a red-emitting light-emitting unit and a cyan-emitting light-emitting unit can be combined. Alternatively, a green-emitting light-emitting unit and a magenta-emitting light-emitting unit can be combined.

[0104] Alternatively, a configuration may be adopted in which three light-emitting units are combined. For example, a configuration may be adopted in which three light-emitting units, a red-emitting light-emitting unit, a green-emitting light-emitting unit, and a blue-emitting light-emitting unit, are combined. Alternatively, a configuration may be adopted in which three light-emitting units, a blue-emitting light-emitting unit, a yellow- or yellow-green-emitting light-emitting unit, and a blue-emitting light-emitting unit, are combined. Alternatively, a configuration may be adopted in which three light-emitting units, a blue-emitting light-emitting unit, a yellow-, yellow-green-, or green-, and red-emitting light-emitting unit, and a blue-emitting light-emitting unit, are combined.

[0105] The order of the number of layers and the colors of the light-emitting units can be, from the anode side, a two-layer structure of B (a blue-emitting light-emitting unit) and Y (a yellow-emitting light-emitting unit), a two-layer structure of B and light-emitting unit X, a three-layer structure of B, Y, and B, or a three-layer structure of B, X, and B. The order of the number of layers and the colors of the light-emitting layers in light-emitting unit X can be, from the anode side, a two-layer structure of R (a red-emitting light-emitting unit) and Y, a two-layer structure of R and G, a two-layer structure of G and R, a three-layer structure of G, R, and G, or a three-layer structure of R, G, and R. Furthermore, another layer can be provided between the two light-emitting layers.

[0106] Here, the light-transmitting region T2 is a region for allowing light to reach the solar cell 30, and therefore must be light-transmitting. Therefore, a conductive film that is light-transmitting at least in the wavelength range of visible light is used for the pixel electrode 111w of the light-emitting device 130w. Examples of such conductive films include In oxide, In—Sn oxide (ITO), In—W oxide, In—W—Zn oxide, In—Ti oxide, In—Ti—Sn oxide, In—Zn oxide, In—Sn—Si oxide (ITSO), and In—Ga—Zn oxide. Therefore, the light-emitting device 130w transmits light L to the substrate 120 side. Ｗ１ and emits light L Ｗ２ can be emitted.

[0107] In the light-transmitting region T2, a pixel circuit 138 for driving the light-emitting device 130w is provided on the layer 101 (see FIG. 5A ). Therefore, it is preferable to provide a light-shielding layer 136 in the region where the light-emitting device 130w and the pixel circuit 138 overlap, in order to prevent fluctuations in the characteristics of transistors and the like due to light irradiation.

[0108] Therefore, the area where the light-shielding layer 136 is not provided in the light-transmitting area T2 is utilized to transmit external light L Ｏ In addition, since the pixel electrode 111w is light-transmitting, the light L emitted from the light-emitting device 130w toward the layer 101 can be transmitted to the solar cell 30. Ｗ２ can also be used for power generation by the solar cell 30.

[0109] It is assumed that the white light emitted by the light-emitting device 130w is used for display, but full color display is basically possible with the subpixels R, G, and B. Therefore, the white light emitted by the light-emitting device 130w plays a strong auxiliary role in display, and even if the intensity of the light emitted toward the display surface is smaller than that of the other subpixels, it can be said that the effect on display quality is small.

[0110] Therefore, in the configuration having the light-transmitting region T2, the light L irradiated onto the display device 40 from the outside Ｏ Furthermore, a portion of the light emitted by the light-emitting device 130w can also be incident on the solar cell 30, thereby increasing the amount of power generation.

[0111] 1, 3A, and 5A show examples in which the sub-pixels are arranged in a matrix, but the arrangement of the sub-pixels is not particularly limited, and various arrangements can be applied, such as a stripe arrangement, an S-stripe arrangement, a matrix arrangement, a delta arrangement, a Bayer arrangement, and a pentile arrangement.

[0112] Examples of the top surface shape of the subpixel include a triangle, a quadrangle (including a rectangle and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, and a circle.

[0113] Fig. 6A is a diagram showing an example in which the sub-pixels and the light-transmitting regions T are arranged in a stripe pattern, and Fig. 6B is a diagram showing an example in which the sub-pixels and the light-transmitting regions T are arranged in a delta pattern.

[0114] Fig. 6C is a diagram showing an example in which one pixel is configured with two rows and three columns. The pixel shown in Fig. 6C has three sub-pixels (R, G, B) in the top row (first row) and a light-transmitting region T in the bottom row (second row). In the pixel shown in Fig. 6C, the R, G, and B are laid out in a stripe arrangement, which can improve display quality.

[0115] Fig. 6D is a diagram showing an example in which one pixel is configured with three rows and two columns. The pixel shown in Fig. 6D has a subpixel R in the top row (first row), a subpixel G in the center row (second row), a subpixel B from the first row to the second row, and a light-transmitting region T in the bottom row (third row). In the pixel shown in Fig. 6D, the layout of R, G, and B is a so-called S-stripe arrangement, which can improve display quality.

[0116] In addition, in FIGS. 6A to 6D, the colors of light emitted by the sub-pixels can be appropriately interchanged.

[0117] 7A and 7B are block diagrams illustrating a display device 40 according to one embodiment of the present invention. The display device 40 includes a pixel array 15, a driver circuit 301, and a driver circuit 303. The pixel array 15 includes pixels 10 arranged in a column direction and a row direction. FIG. 7A illustrates an example in which the pixel 10 includes a light-transmitting region T1, and FIG. 7B illustrates an example in which the pixel 10 includes a light-transmitting region T2. ​​Note that although an example in which the display device 40 is an active matrix display device is described here, the display device 40 may also be a passive matrix display device.

[0118] The drive circuits 301 and 303 are drivers for driving the pixel array 15. For the drive circuits 301 and 303, for example, a shift register circuit that operates at high speed can be used.

[0119] The driver circuit 301 can function as a gate driver, and the driver circuit 303 can function as a source driver. The driver circuit 301 is electrically connected to the pixels via gate lines GL. The driver circuit 303 is electrically connected to the pixels via source lines SL. A demultiplexer can also be provided between the driver circuit 303 and the pixels.

[0120] 7C shows an example of a pixel circuit that can be applied to a pixel. The pixel circuit includes a transistor M1, a transistor M2, a transistor M3, a capacitor C1, and a light-emitting device EL. The pixel circuit is electrically connected to a gate line GL and a source line SL (see FIG. 7A).

[0121] The gate of the transistor M1 is electrically connected to the gate line GL, and one of the source or drain is electrically connected to the source line SL, and the other is electrically connected to one electrode of the capacitor C1 and the gate of the transistor M2. The transistor M2 has one of the source or drain electrically connected to a wiring AL, and the other of the source or drain electrically connected to one electrode of the light-emitting device EL, the other electrode of the capacitor C1, and one of the source or drain of the transistor M3. The transistor M3 has the gate electrically connected to the gate line GL, and the other of the source or drain electrically connected to a wiring RL. The other electrode of the light-emitting device EL is electrically connected to a wiring CL.

[0122] A data potential is applied to the source line SL, and a selection signal is applied to the gate line GL. The selection signal includes a potential that turns on a transistor and a potential that turns off a transistor.

[0123] A reset potential is applied to the wiring RL. An anode potential is applied to the wiring AL. A cathode potential is applied to the wiring CL. The anode potential is higher than the cathode potential. The reset potential applied to the wiring RL can be a potential such that the potential difference between the reset potential and the cathode potential is smaller than the threshold voltage of the light-emitting device EL. The reset potential can be a potential higher than the cathode potential, the same as the cathode potential, or a potential lower than the cathode potential.

[0124] The transistors M1 and M3 function as switches. The transistor M2 functions as a transistor for controlling the current flowing through the light-emitting device EL. For example, it can be said that the transistor M1 functions as a selection transistor and the transistor M2 functions as a drive transistor.

[0125] Here, the transistors M1 to M3 can be transistors having metal oxide in their channel formation regions (hereinafter referred to as OS transistors). Alternatively, all of the transistors M1 to M3 can be transistors having silicon (single crystal silicon, polycrystalline silicon, microcrystalline silicon, or amorphous silicon) in their channel formation regions (hereinafter referred to as Si transistors). Alternatively, the transistors M1 and M3 can be OS transistors, and the transistor M2 can be a Si transistor.

[0126] Alternatively, one or more of the transistors included in the driver circuits 301 and 303 may be Si transistors and the remaining transistors may be OS transistors. Alternatively, one or more of the driver circuits 301 and 303 may be Si transistors and the remaining transistors may be OS transistors.

[0127] As the OS transistor, a transistor including an oxide semiconductor in a semiconductor layer in which a channel is formed can be used. The semiconductor layer preferably contains indium. Alternatively, the semiconductor layer preferably contains indium, M (M is one or more elements selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more elements selected from aluminum, gallium, yttrium, and tin.

[0128] For example, for a semiconductor layer of an OS transistor, an oxide containing indium (InOx) is preferably used. Alternatively, an oxide containing indium and gallium (also referred to as IGO) is preferably used. Alternatively, an oxide containing indium, gallium, and zinc (also referred to as IGZO) is preferably used. Alternatively, an oxide containing indium, tin, and zinc is preferably used. Alternatively, an oxide containing indium, gallium, tin, and zinc is preferably used.

[0129] A transistor using an oxide semiconductor, which has a wider band gap and a lower carrier concentration than silicon, can achieve an extremely small off-state current. Therefore, due to the small off-state current, charge stored in a capacitor connected in series with the transistor can be held for a long period of time. Therefore, it is preferable to use a transistor including an oxide semiconductor for each of the transistors M1 and M3 connected in series with the capacitor C1. Using transistors including an oxide semiconductor as the transistors M1 and M3 can prevent charge held in the capacitor C1 from leaking through the transistor M1 or M3. Furthermore, because charge held in the capacitor C1 can be held for a long period of time, a still image can be displayed for a long period of time without rewriting pixel data.

[0130] Although the transistors are shown as n-channel transistors in FIG. 7C, p-channel transistors can also be used.

[0131] Further, as a transistor included in a pixel circuit, a transistor having a pair of gates overlapping with each other with a semiconductor layer interposed therebetween can be used.

[0132] In a transistor having a pair of gates, when the pair of gates are electrically connected to each other and are supplied with the same potential, the on-state current of the transistor is increased and the saturation characteristics are improved. Furthermore, a potential for controlling the threshold voltage of the transistor can be applied to one of the pair of gates. Furthermore, applying a constant potential to one of the pair of gates can improve the stability of the electrical characteristics of the transistor. For example, one gate of the transistor can be electrically connected to a wiring to which a constant potential is applied. Alternatively, one gate of the transistor can be electrically connected to a source or a drain.

[0133] 7D is an example in which transistors M1 and M3 each have a pair of gates. The pair of gates of the transistors M1 and M3 are electrically connected. This configuration can shorten the period for writing data to the pixel circuit.

[0134] 8A is an exploded perspective view illustrating a portable terminal 50a, which is an example of an electronic device of one embodiment of the present invention. Specific examples of the portable terminal 50a include a smartphone and a tablet computer. The display device 40, solar cell 30, circuit portion 21, and secondary battery 22 described in FIG. 1 can be housed in a housing 20, and a front panel 24 is provided on the display device 40. The front panel 24 has a light-transmitting window portion 24a and a frame portion 24b, and a user can view the display through the window portion 24a. The front panel 24 can be formed of glass or the like that transmits visible light.

[0135] A camera module can be provided in circuit unit 21, and Fig. 8A shows camera module 23 and lens 23L corresponding to an in-camera. Camera module 23 has an image sensor and lens 23L that projects an image onto the image sensor. Camera module 23 can also be configured so as not to overlap display device 40 and solar cell 30, and a lighting section can be provided in frame section 24b. However, Fig. 8A illustrates a configuration in which camera module 23 overlaps display device 40 and solar cell 30.

[0136] The solar cell 30 is opaque because it uses a reflective electrode such as a metal electrode on the back side. Therefore, when it is to be overlapped with the camera module 23, an opening 31 having a diameter at least equal to or greater than the diameter of the lens 23L is provided, and the lens 23L is positioned so as to overlap the opening 31. If the support substrate is translucent, the opening 31 can be formed by partially removing a structure on the support substrate, but if the support substrate is made of a material that is easy to drill, such as a film or metal foil, the opening 31 may also be formed by punching.

[0137] In addition, in the solar cell 30, it is preferable to connect multiple stages of cells in series to obtain the required voltage. In this specification, a cell refers to a stack of photoelectric conversion layers and electrodes, and is the minimum configuration that functions as a solar cell. In general, in thin-film solar cells, multiple cells are formed by performing a process of dividing a photoelectric conversion layer or electrodes formed over a large area.

[0138] When light is evenly irradiated onto the light-receiving surface of a solar cell in which multiple stages of cells are connected in series, the current obtained from the solar cell is determined by the bottleneck of the cell with the smallest area. Therefore, it is preferable that each of the multiple stages of cells has a light-receiving surface of equal area.

[0139] Therefore, as shown in FIG. 8A, for example, when the solar cell 30 is a series connection of six stages of cells C1 to C6, it is preferable that the area of ​​the light receiving portion (excluding the area of ​​the opening 31) is equal for each of the cells C1 to C6.

[0140] Since the display device 40 cannot be said to be transparent, an opening may be formed in the display device 40 and the opening may be arranged so as to overlap the lens 23L. However, the display device 40 of one embodiment of the present invention has a light-transmitting region T and is highly light-transmitting, and therefore can be said to be suitable for the under-display camera (UDC) system.

[0141] The UDC method is a method of capturing an initial image by capturing light passing through between pixels with a camera, and then improving the image quality by performing image processing, etc. The initial image captured by the camera is a low-quality image with information missing due to pixel occlusion, but by using artificial intelligence trained by deep learning, etc., a high-quality image can be obtained.

[0142] Because very little light passes through between pixels, typical UDC methods involve thinning out or reducing the size of pixels in the area where the display camera overlaps. In this way, the spacing between pixels is widened to increase the amount of light passing through and maximize the quality of the initial image. Even when image processing is performed, the lower the quality of the initial image, the more difficult it is to obtain a high-quality image.

[0143] Because the area overlapping with the camera is small relative to the entire display, reducing the pixel area in that area has little effect on visibility. However, depending on the angle from which the display is viewed, the area may be clearly visible, which can make the display appear unnatural. Furthermore, if the pixel area in that area is increased to prevent the area from being visible, the amount of information that can be acquired by the camera decreases, lowering the quality of the initial image.

[0144] 8B is a top view (left) of a display device 40 according to one embodiment of the present invention and an enlarged view (right) of a region where the display device 40 overlaps with the lens 23L of the camera module 23. As described above, the display device 40 has a light-transmitting region T in the pixel 10, and therefore the display device as a whole has a relatively high transmittance. Therefore, a high-quality initial image can be obtained in the region where the display camera overlaps without changing the pixel arrangement. Furthermore, because the pixels are evenly arranged across the entire display surface, the region where the display camera overlaps is unlikely to appear unnatural.

[0145] 9A is an exploded perspective view illustrating a wristwatch-type terminal 50b, which is an example of an electronic device of one embodiment of the present invention. The display device 40, solar cell 30, circuit unit 21, and secondary battery 22 described in FIG. 1 can be housed in a housing 20, and a front panel 24 is provided on the display device 40. The front panel 24 has a light-transmitting window portion 24a and a frame portion 24b, and a user can view the display through the window portion 24a. The front panel 24 can be made of glass or the like. Note that in the wristwatch-type terminal 50b, the window portion 24a may be formed as a windshield, and the frame portion 24b may be formed as a bezel.

[0146] 9A shows a configuration in which the shape of the display device 40 in a top view is circular and the other elements are also correspondingly approximately circular in a top view, but this is not limiting. The shapes of the display device 40 and the other elements are not important and can be determined taking functionality and design into consideration.

[0147] As in the case of the portable terminal 50a, the solar cell 30 preferably has multiple stages of cells connected in series to obtain the required voltage. As mentioned above, the cell with the smallest area becomes the bottleneck in the current obtained from the solar cell 30, so it is preferable that each of the multiple stages of cells has an equal area of ​​light-receiving surface. Figure 9A shows an example of a solar cell 30 with a circular outer shape and five stages of cells shaped like a circle divided by multiple parallel lines. In this case, cells C1 to C5 do not have the same shape, but it is preferable that the areas of the light-receiving portions are the same.

[0148] In addition, in a configuration in which the minor axes of the multiple cells of the solar cell 30 are aligned parallel to one another, as shown in Figure 9B, it is preferable that the direction D1 in which the band 25 is provided on the housing 20 is the same as the direction D2 in which the multiple cells of the solar cell 30 are aligned. In other words, it can be said that it is preferable that the housing 20 has a first region 26a that functions as a connection portion for the band 25 and a second region 26b that faces the first region 26a, and that the direction D1 in which the first region 26a and the second region 26b are aligned is the same as the direction D2 in which the multiple cells are aligned. It can also be said that it is preferable that the direction D1 is perpendicular to the longitudinal direction of the cells.

[0149] This is because, as shown in Figure 10A, when terminal 50b is worn on the arm, part of the display surface of terminal 50b is blocked by the sleeve 70 of clothing, etc., and power generation is possible even if one of the cells becomes a bottleneck.

[0150] In an integrated solar cell, if any of the cells connected in series is shaded, current cannot flow even if the other cells receive light, and power generation is not possible. Therefore, as shown in Figure 10B, if the direction in which the band 25 is attached to the housing 20 is perpendicular to the direction in which the multiple cells of the solar cell 30 are arranged, power generation will not be possible if cell C1 is shaded, even if part of the display surface is shaded. The configuration shown in Figure 10A can be said to increase the probability of power generation even if part of the display surface of the terminal 50b is shaded by the sleeve 70.

[0151] The shape of the cells connected in series is not limited to the above. For example, as shown in FIG. 9C, cells C1 to C5 may be fan-shaped. By forming the cells in a fan shape, all the cells can have the same shape, making it easier to obtain stable electrical characteristics. In this configuration, power generation is possible as long as one side is not shaded.

[0152] 9D, cell C1 may be placed in the center, and donut-shaped cells C2 to C6 may be placed around it in sequence. This configuration also reduces the effect of shading, and power generation is possible as long as cell C1 is not shaded.

[0153] As described above in this embodiment, in an electronic device according to one embodiment of the present invention, a large amount of light can be incident on a solar cell disposed on the back side of a display device, thereby increasing the amount of power generated. Furthermore, the power generated by the solar cell can be stored in a secondary battery, and the secondary battery can supply power to the display device and other devices included in the electronic device. Therefore, part of the power consumed by the electronic device can be generated by the solar cell, thereby extending the charging interval for the user and improving convenience.

[0154] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0155] Embodiment 2 In this embodiment, a solar cell that can be used for an electronic device of one embodiment of the present invention will be described.

[0156] As described in Embodiment 1, since the electronic device of one embodiment of the present invention is expected to be used indoors and outdoors, it is preferable that the photoelectric conversion layer of the solar cell 30 have high sensitivity to visible light. Furthermore, it is preferable that the solar cell 30 be thin so that it can be housed inside the housing of the electronic device, and that it be easy to integrate so that it generates a voltage necessary to charge the secondary battery 22.

[0157] Therefore, the solar cell 30 is made of amorphous silicon and CIS (CuInSe) ２ ), CIGS(Cu(In,Ga)Se ２ ), Cu ２ It is preferable to use a thin-film solar cell that uses amorphous silicon or perovskite crystal, or a tandem type thin-film solar cell in which two or more of them are stacked. Among these, a thin-film solar cell that uses amorphous silicon or perovskite crystal, which has a peak of spectral sensitivity in the visible light wavelength region, as a photoelectric conversion layer, is particularly preferable.

[0158] 11A and 11B show an example of the layered structure of the solar cell 30. Fig. 11A shows a configuration in which light L is incident from the side of the substrate 560, which serves as a support, and is a structure in which a light-transmitting substrate such as a glass substrate or a light-transmitting resin is mainly used for the substrate 560. In this structure, the substrate 560 can also serve as a protective window.

[0159] 11B shows a configuration in which light L is incident from the opposite side of the substrate 560, which is a support. The substrate 560 is not limited to a light-transmitting substrate, and a non-light-transmitting substrate such as a metal, ceramic, or colored resin can also be used. Since the type of substrate 560 is not limited in this configuration, it is effective for flexible solar cells, etc. Note that the structure of the solar cell described in this embodiment is an example, and elements other than the illustrated layers may be provided. Furthermore, some of the illustrated layers may not be provided.

[0160] 11A and 11B show a configuration in which the photoelectric conversion layer 500 is sandwiched between an electrode 540 and an electrode 550. Here, the electrode 540 is on the light-receiving side and is therefore formed using a light-transmitting conductive film. The electrode 540 may be made of, for example, an In oxide, Sn oxide, In—Sn oxide (ITO), F-doped Sn oxide (FTO), Zn oxide, Ga-doped Zn oxide (GZO), In—W oxide, In—W—Zn oxide, In—Ti oxide, In—Ti—Sn oxide, In—Zn oxide, In—Sn—Si oxide (ITSO), or In—Ga—Zn oxide, all of which have a high transmittance to visible light.

[0161] Since the electrode 550 is provided on the opposite side of the light-receiving surface, it is preferable to form the electrode 550 from a metal film with high reflectivity so that light that is not absorbed by the photoelectric conversion layer 500 but is transmitted through the electrode 550 is reflected and returned to the photoelectric conversion layer 500. For example, metal films such as Al, Ti, Ni, Ag, Ag-Pd-Cu, and SUS can be used. The metal film is not limited to a single layer, and may be a laminate of different films. For example, a laminate of Al and SUS can be used. Furthermore, the electrode 550 can also be made of a conductive paste such as carbon paste, nickel paste, silver paste, or molybdenum paste.

[0162] Incidentally, minute irregularities may be formed at the interfaces of the laminate of electrode 540, photoelectric conversion layer 500, and electrode 550. The irregularities on the light-receiving surface side of photoelectric conversion layer 500 diffuse incident light, and the irregularities on the back surface side act to repeatedly diffusely reflect light, creating a light trapping effect that can improve the power generation efficiency of solar cell 30.

[0163] For example, as shown in Figure 11C, in the case where light L is incident from the substrate 560 side, layers are formed in the order of electrode 540, photoelectric conversion layer 500, and electrode 550 on the substrate 560, so that unevenness can be formed on the surface of electrode 540.

[0164] 11D , in the case where light L is incident from the surface opposite to the substrate 560, the electrode 550, the photoelectric conversion layer 500, and the electrode 540 are formed in this order on the substrate 560, and therefore, the unevenness may be formed on the surface of the electrode 550. The average roughness (Ra) of the unevenness on the surface of the electrode 540 or the electrode 550 is preferably about 10 nm to 1000 nm, taking into consideration the optical effect and the coverage of the film to be laminated.

[0165] The unevenness can be obtained by, for example, forming the electrode 540 or the electrode 550 using a liquid phase method or a gas phase method under conditions that generate hillocks. Alternatively, regular unevenness may be formed using a lithography method using nanoimprinting and an etching method. Alternatively, unevenness may be formed in advance on the surface of the substrate 560 using a laser processing method or the like, and the electrode 540 or the electrode 550 may be formed on the uneven surface.

[0166] Here, a description will be given of an embodiment in which amorphous silicon is used for the photoelectric conversion layer 500. The photoelectric conversion layer 500 has a pin junction, and has a structure in which a layer 510 is sandwiched between a layer 520 and a layer 530.

[0167] A semiconductor layer having one conductivity type can be used for the layer 520, and a semiconductor layer having the opposite conductivity type to that of the layer 520 can be used for the layer 530. For example, a p-type silicon semiconductor layer can be used for the layer 520, and an n-type silicon semiconductor layer can be used for the layer 530. Alternatively, the opposite conductivity types can be used. Note that although amorphous silicon can be used for the silicon semiconductor layer, microcrystalline silicon or polycrystalline silicon, which has a lower resistance, can also be used.

[0168] An i-type amorphous silicon semiconductor layer, which is an intrinsic semiconductor, can be used for the layer 510. In this specification, the intrinsic semiconductor refers to a semiconductor in which the Fermi level is located in the center of the band gap, as well as a semiconductor in which the impurity imparting p-type or n-type is 1×10 ２０ cm −３ The term "intrinsic semiconductor" refers to a semiconductor having a photoconductivity 100 times or more higher than the dark conductivity at a concentration of 0.1 or less than 0.1%. This intrinsic semiconductor includes those containing impurity elements from Group 13 or 15 of the periodic table.

[0169] Next, a description will be given of an embodiment in which a perovskite crystal is used for the photoelectric conversion layer 500. The photoelectric conversion layer 500 has a configuration essentially equivalent to a pin junction, with a layer 510 sandwiched between layers 520 and 530. Although not shown in FIGS. 11A to 11D , a buffer layer may be formed in one or more regions selected from the interface between the electrode 550 and layer 530, the interface between the layer 530 and layer 510, the interface between the layer 510 and layer 520, and the interface between the layer 520 and electrode 570. The buffer layer functions to modify the interface between each electrode and layer or the interface between each layer. The buffer layer can be made of inorganic or organic materials, and the physical properties, such as semiconductor, conductor, or insulator, can be selected by the implementer as appropriate. The provision of a buffer layer can improve the conversion efficiency of the solar cell 30.

[0170] One of the layers 520 and 530 can be made of a material that acts as an electron transport layer (corresponding to an n-type layer). The material for the electron transport layer is not particularly limited as long as it is a material that can increase the efficiency of electron extraction from the layer 520 to one of the electrodes 540 and 550. For example, inorganic compounds such as salts of alkali metals such as lithium, sodium, potassium, or cesium, or metal oxides such as zinc oxide, titanium oxide, aluminum oxide, or indium oxide can be used. Alternatively, bathocuproine (BCP), bathophenanthroline (Bphen), tris(8-hydroxyquinolinato)aluminum (Alq), or the like can be used. ３ ), boron compounds, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic anhydride (NTCDA), perylenetetracarboxylic anhydride (PTCDA), or fullerene compounds (e.g., PCBM: [6,6]-phenyl C ６１ Organic compounds such as butyric acid methyl ester can be used.

[0171] The other of the layers 520 and 530 can be made of a material that functions as a hole transport layer (corresponding to a p-type layer). The material for the hole transport layer is not particularly limited as long as it can increase the efficiency of extracting holes from the layer 520 to the other of the electrodes 540 and 550. For example, inorganic compounds such as metal oxides, such as copper oxide, nickel oxide, manganese oxide, iron oxide, molybdenum oxide, vanadium oxide, and tungsten oxide, can be used. Alternatively, polymers such as polythiophene, polypyrrole, polyacetylene, poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (abbreviated as PEDOT / PSS), conductive organic compounds such as (3-hexylthiophene-2,5-diyl) (abbreviated as P3HT) and arylamine, or organic compounds such as Nafion can be used.

[0172] The layer 510 for generating carriers by light irradiation has a crystal composition of ABX ３ It is preferable to have an organic-inorganic perovskite crystal (corresponding to an i-type layer) represented by the formula (A: monovalent cation, B: divalent cation, X: halide ion). For example, it is preferable to use methylamine, ethylamine, pentylcarboxyamine, formamidinium, guanidine, or ions thereof at the A site. It is preferable to use metals such as lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium at the B site. It is preferable to use halides such as chlorine, bromine, and iodine at the X site.

[0173] The layer 510 is typically made of CH ３ NH ３ PbI ３ , C.H. ３ NH ３ PbBr ３ , C.H. ３ NH ３ SnI ３A solar cell using a perovskite crystal for the photoelectric conversion layer 500 has a high open-circuit voltage of about 1 V, and therefore has high power generation efficiency even indoors with little light, making it suitable for the electronic device of one embodiment of the present invention.

[0174] The configuration of the solar cell 30 shown in Figures 11A to 11D allows layers other than the substrate 560 to be formed from thin films, making it easy to integrate the cells, which can be divided into multiple parts and connected in series without the need to add wiring or the like later.

[0175] As an example of integration, Figure 12A shows a cross-sectional view of four stages of cells connected in series. Note that Figure 12A shows the configuration of Figure 11A, where layer 520 is a p-type layer and layer 530 is an n-type layer. Since holes are extracted from the p-type layer, the electrode 540 connected thereto is a positive pole (+). Furthermore, since electrons are extracted from the n-type layer, the electrode 550 connected thereto is a negative pole (-).

[0176] The basic structure of one cell is as shown in Fig. 11A, and the conductive layer that becomes the electrode and the semiconductor layer that becomes the photoelectric conversion layer are divided into multiple cells using a laser scribing method, a mechanical scribing method, a lithography method, an etching method, etc. Two adjacent cells are connected in series by connecting the electrode 550 of one cell to the electrode 540 of the other cell.

[0177] In this case, in one cell, the electrode 550 is in contact with the layer 520, but the energy barrier between the electrode 550 and the layer 520 may be large. In such a case, the resistance between the electrode 550 and the layer 520 is high, and the layer 520 has a relatively high resistance in the surface direction, so the resistance between the electrode 550 and the electrode 540 via the layer 520 is also high, and the cell operates. Note that the fill factor (FF) of the cell can be increased by further increasing the resistance between the electrode 550 and the electrode 540 by adding a step of further dividing the layer 520 or a step of providing an insulating layer.

[0178] 11A to 11D show examples of single-cell structures, but tandem structures are also possible. Fig. 12B shows the cell structure of a tandem solar cell with a two-terminal structure. Note that electrodes 540 and 550 are marked with circles as terminals and each shows a (+) or (-) polarity, but the polarities may be reversed as long as they form a pair. Also, the support substrate is omitted from the illustration.

[0179] In the two-terminal structure, a light-transmitting electrode 570 is provided between the two photoelectric conversion layers. A portion of light L1 incident from the electrode 540 side is absorbed by the photoelectric conversion layer 500a, and light L2 that is not absorbed by the photoelectric conversion layer 500a is absorbed by the photoelectric conversion layer 500b. The photoelectric conversion layer 500a can also be called the top cell, and the photoelectric conversion layer 500b can also be called the bottom cell.

[0180] Therefore, it is preferable to use a semiconductor material with a larger band gap for the photoelectric conversion layer 500a than for the photoelectric conversion layer 500b. With this configuration, the photoelectric conversion layer 500a absorbs the short wavelength light contained in the light L2 and uses it for photoelectric conversion, and the photoelectric conversion layer 500b absorbs the long wavelength light L2 that transmits through the photoelectric conversion layer 500a and uses it for photoelectric conversion.

[0181] As described above, it is preferable that the materials used for the photoelectric conversion layer 500a and the photoelectric conversion layer 500b have different absorption wavelengths. Because the absorption wavelengths of amorphous silicon and perovskite crystal overlap, it is preferable to use either amorphous silicon or perovskite crystal for one of the photoelectric conversion layer 500a and the photoelectric conversion layer 500b, and use another material for the other of the photoelectric conversion layer 500a and the photoelectric conversion layer 500b.

[0182] Because amorphous silicon and perovskite crystals have light absorption peaks in the wavelength range of visible light, the other of the photoelectric conversion layers 500a and 500b is preferably a material that absorbs light with wavelengths longer than visible light. Light with wavelengths longer than visible light is abundant in ambient light, etc. Examples of such materials include crystalline silicon thin films such as microcrystalline silicon and polycrystalline silicon, CIS, and CIGS.

[0183] Therefore, in a tandem solar cell that can be used in one embodiment of the present invention, it is preferable to use amorphous silicon or perovskite crystal for the top cell and crystalline silicon thin film, CIS, or CIGS for the bottom cell. ２ O can also be used.

[0184] In the two-terminal tandem structure shown in Figure 12B, the top and bottom cells are connected in series, so sufficient characteristics cannot be obtained unless current matching is performed to match the number of carriers generated in the two cells. Two-terminal cells are easy to connect to circuits, but there are various constraints on current matching and they are easily affected by process variations, etc.

[0185] 12C , a four-terminal tandem structure in which the top cell and the bottom cell are independent of each other may be used. In this case, the top cell uses a light-transmitting electrode 570a as the electrode paired with the electrode 540, and the bottom cell uses a light-transmitting electrode 570b as the electrode paired with the electrode 540, so that light L2 passing through the top cell is incident on the bottom cell.

[0186] In the top cell, one of a pair of terminals is provided on electrode 540, and the other of the pair of terminals is provided on electrode 570a. In the bottom cell, one of a pair of terminals is provided on electrode 550, and the other of the pair of terminals is provided on electrode 570b. With this configuration, power can be extracted independently from the top cell and the bottom cell. Although a four-terminal cell may require more circuits to be connected, it does not require current matching between the top cell and the bottom cell.

[0187] The solar cell structure described above has high sensitivity to visible light and can be formed as a thin film, so it is thin and lightweight. Therefore, it is suitable for use in the electronic device of one embodiment of the present invention.

[0188] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0189] Embodiment 3 In this embodiment, an example of a display device according to one embodiment of the present invention will be described.

[0190] 13A shows an example of a cross section of a part of a region including the driving circuit 301, a part of a region including the pixel array 15, and a part of a region including the driving circuit 303 in the display device 40 shown in FIG. 7A. In the pixel array 15, a subpixel B that emits blue light and a pixel 10 having a light-transmitting region T1 are shown as an example.

[0191] The display device 40 includes, between the substrate 110 and the substrate 120, a transistor 201, a transistor 202, a transistor 203, a light-emitting device 130b included in the sub-pixel B, and the like.

[0192] The light-emitting device 130b includes a conductive layer 142b, a conductive layer 146b on the conductive layer 142b, and a conductive layer 149b on the conductive layer 146b. All or some of the conductive layers 142b, 146b, and 149b may be called pixel electrodes.

[0193] The conductive layer 142b is connected to a conductive layer 222b included in the transistor 202 through an opening provided in the insulating layer 214. For example, a conductive layer functioning as a reflective electrode can be used for the conductive layer 142b and the conductive layer 146b, and a conductive layer functioning as a transparent electrode can be used for the conductive layer 149b.

[0194] A recess is formed in the conductive layer 142b so as to cover the opening provided in the insulating layer 214. A layer 148 is buried in the recess.

[0195] The layer 148 has a function of planarizing the recessed portion of the conductive layer 142b. A conductive layer 146b electrically connected to the conductive layer 142b is provided over the conductive layer 142b and the layer 148. Therefore, a region overlapping with the recessed portion of the conductive layer 142b can also be used as a light-emitting region, thereby increasing the aperture ratio of the pixel.

[0196] The layer 148 is not limited to an insulating layer, and a conductive layer can also be used. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used as appropriate for the layer 148. In particular, the layer 148 is preferably formed using an insulating material, and is particularly preferably formed using an organic insulating material.

[0197] A protective layer 131 is provided on the light-emitting device 130b. An adhesive layer 122 is provided between the protective layer 131 and the substrate 120.

[0198] The display device is a top-emission type. Light emitted by the light-emitting device is emitted toward the substrate 120. The substrate 120 is preferably made of a material that is highly transparent to visible light. The pixel electrodes contain a material that reflects visible light, and the counter electrode (common electrode 117) contains a material that transmits visible light.

[0199] The transistors 201 to 203 are all formed over a substrate 110. The transistors 201 to 203 can be manufactured using the same material and through the same process.

[0200] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 110 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 is provided to cover the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be two or more layers rather than a single layer.

[0201] It is preferable that at least one insulating layer covering the transistor is made of a material that is resistant to the diffusion of impurities such as water and hydrogen. This allows the insulating layer to function as a barrier layer. With this structure, it is possible to effectively prevent impurities from diffusing into the transistor from the outside, thereby improving the reliability of the display device.

[0202] It is preferable to use an inorganic insulating film for each of the insulating layers 211, 213, and 215. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. Also usable are a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film. Two or more of the above insulating films can also be stacked.

[0203] An organic insulating layer is suitable for the insulating layer 214, which functions as a planarizing layer. Materials that can be used for the organic insulating layer include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenolic resin, and precursors of these resins. The insulating layer 214 can also have a laminated structure of an organic insulating layer and an inorganic insulating layer. The outermost layer of the insulating layer 214 preferably functions as an etching protection layer.

[0204] The transistors 201 to 203 each include a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as a source and a drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0205] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a vertical transistor, a planar transistor, a fin transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. A bottom-gate transistor structure can also be used instead of a top-gate transistor structure. Alternatively, a gate can be provided only on one side of a semiconductor layer where a channel is formed, instead of both above and below the semiconductor layer.

[0206] The transistors 201 to 203 have a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates are connected and the same signal is supplied to drive the transistors. Alternatively, the transistors can be driven by applying a potential for controlling the threshold voltage to one of the two gates and a potential for driving to the other.

[0207] The semiconductor layer of the transistor preferably contains a metal oxide (also referred to as an oxide semiconductor). That is, the display device of this embodiment preferably uses an OS transistor using a metal oxide for a channel formation region. For the metal oxide that can be used for the OS transistor, the description in Embodiment 3 can be referred to.

[0208] All of the transistors included in the display device can be OS transistors, or all of the transistors included in the display device can be Si transistors, or some of the transistors included in the display device can be OS transistors and the rest can be Si transistors.

[0209] Alternatively, an OS transistor can be provided over a Si transistor, or OS transistors can be stacked.

[0210] Examples of silicon include single crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, a transistor having low temperature polysilicon (LTPS) in a semiconductor layer (hereinafter also referred to as an LTPS transistor) can be used. The LTPS transistor has high field-effect mobility and favorable frequency characteristics.

[0211] By using Si transistors such as LTPS transistors, circuits that need to be driven at high frequencies (such as source drivers) can be built on the same substrate as the display unit, which simplifies the external circuits mounted on the display device and reduces component and mounting costs.

[0212] For example, by using both an LTPS transistor and an OS transistor in the pixel array 15, a display device with low power consumption and high driving capability can be realized. A configuration in which an LTPS transistor and an OS transistor are combined is sometimes referred to as LTPO. As a more preferred example, it is preferable to use an OS transistor as a transistor that functions as a switch for controlling conduction / non-conduction between wirings, and to use an LTPS transistor as a transistor for controlling current.

[0213] For example, one of the transistors in the pixel array 15 functions as a transistor for controlling the current flowing through the light-emitting device, and can also be called a drive transistor. One of the source and drain of the drive transistor is electrically connected to the pixel electrode of the light-emitting device. It is preferable to use an LTPS transistor as the drive transistor. This allows the current flowing through the light-emitting device in the pixel circuit to be large.

[0214] Meanwhile, another transistor in the pixel array 15 functions as a switch for controlling pixel selection and non-selection and can also be called a selection transistor. The gate of the selection transistor is electrically connected to a gate line, and one of the source and drain is electrically connected to a source line (signal line). It is preferable to use an OS transistor as the selection transistor. This allows pixel gradation to be maintained even when the frame frequency is significantly low (for example, 1 fps or less), and therefore power consumption can be reduced by stopping the driver when displaying a still image.

[0215] As described above, the display device of one embodiment of the present invention can have a high aperture ratio, high definition, high display quality, and low power consumption.

[0216] A display device according to one embodiment of the present invention includes an OS transistor and a light-emitting device with a metal maskless (MML) structure. This structure significantly reduces leakage current that may flow through the transistor and leakage current that may flow between adjacent light-emitting devices (also referred to as lateral leakage current or side leakage current). Furthermore, when an image is displayed on the display device, the viewer can observe one or more of image clarity, image sharpness, high saturation, and a high contrast ratio. The extremely low leakage current that may flow through the transistor and lateral leakage current between the light-emitting devices significantly reduces light leakage during black display (so-called floating black).

[0217] 13B and 13C show other structural examples of transistors that can be used as the transistors 201 to 203. FIG.

[0218] The transistor 205 and the transistor 206 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a semiconductor layer 231 having a channel formation region 231i and a pair of low-resistance regions 231n, a conductive layer 222a connected to one of the pair of low-resistance regions 231n, a conductive layer 222b connected to the other of the pair of low-resistance regions 231n, an insulating layer 225 functioning as a gate insulating layer, a conductive layer 223 functioning as a gate, and an insulating layer 215 covering the conductive layer 223. The insulating layer 211 is located between the conductive layer 221 and the channel formation region 231i. The insulating layer 225 is located at least between the conductive layer 223 and the channel formation region 231i. Furthermore, an insulating layer 218 covering the transistor may be provided.

[0219] 13B shows an example in which the insulating layer 225 covers the top surface and side surfaces of the semiconductor layer 231. The conductive layer 222a and the conductive layer 222b are connected to the low-resistance region 231n through openings provided in the insulating layer 225 and the insulating layer 215, respectively. One of the conductive layer 222a and the conductive layer 222b functions as a source, and the other functions as a drain.

[0220] 13C , the insulating layer 225 overlaps with the channel formation region 231i of the semiconductor layer 231 but does not overlap with the low-resistance region 231n. For example, the insulating layer 225 can be processed using the conductive layer 223 as a mask to form the structure shown in FIG. 13C . In FIG. 13C , the insulating layer 215 is provided to cover the insulating layer 225 and the conductive layer 223, and the conductive layer 222a and the conductive layer 222b are each connected to the low-resistance region 231n through openings in the insulating layer 215.

[0221] A connection portion 230 is provided in a region of the substrate 110 where the substrate 120 does not overlap. In the connection portion 230, the wiring 165 is electrically connected to the FPC 119 via a conductive layer 166 and a connection layer 242. The conductive layer 166 has an example of a stacked structure including a conductive film obtained by processing the same conductive film as the conductive layer 142b, a conductive film obtained by processing the same conductive film as the conductive layer 146b, and a conductive film obtained by processing the same conductive film as the conductive layer 149b. The conductive layer 166 is exposed on the top surface of the connection portion 230. This allows the connection portion 230 and the FPC 119 to be electrically connected via the connection layer 242.

[0222] The connection layer 242 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0223] A light-shielding layer 135 can be provided between the adhesive layer 122 and the substrate 120. The light-shielding layer 135 can be provided so as to have a region between adjacent light-emitting devices, a region overlapping with the driving circuit 301, and a region overlapping with the driving circuit 303.

[0224] The light-emitting device 130b is a light-emitting device that emits blue light. Alternatively, the light-emitting device 130b may be a light-emitting device that emits white light, and a color filter 137 that transmits blue light may be provided so as to overlap the light-emitting device 130b.

[0225] The light-transmitting region T is configured to include as few transistor and light-emitting device components as possible, allowing light to easily pass through the substrate 110 from the substrate 120 and reach the solar cell 30. However, components of the transistor and light-emitting device of an adjacent subpixel that are made of a material with high transmittance in the wavelength range of visible light or blue to red light may extend into the light-transmitting region T.

[0226] Note that vertical transistors can also be used as the transistors 201 to 203 included in the display device 40. By using vertical transistors, the area occupied by the transistors is reduced, which makes it easier to incorporate a correction circuit or the like into the pixel circuit.

[0227] 14A and 14B are diagrams illustrating a vertical transistor. Fig. 14A is a top view. Fig. 14B is a cross-sectional perspective view taken along line A1-A2, illustrating the depth direction of region d shown in Fig. 14A. Note that for clarity, some elements are omitted in Fig. 14A and 14B.

[0228] The transistor 210, which is a vertical transistor, can be provided over a substrate 402. The transistor 210 includes a conductive layer 404, a conductive layer 404e, an insulating layer 406, a semiconductor layer 408, a conductive layer 412a, and a conductive layer 412b. The conductive layer 404 is a gate line and is electrically connected to the conductive layer 404e, which functions as a gate electrode. A part of the insulating layer 406 functions as a gate insulating layer. The conductive layer 412a functions as one of a source electrode and a drain electrode. The conductive layer 412b functions as the other of the source electrode and the drain electrode.

[0229] A conductive layer 412a is provided over the substrate 402, an insulating layer 407 (insulating layers 407a, 407b, and 407c) is provided over the conductive layer 412a, and a conductive layer 412b is provided over the insulating layer 407. The insulating layer 407 has a region sandwiched between the conductive layers 412a and 412b. The conductive layer 412a has a region overlapping with the conductive layer 412b with the insulating layer 407 interposed therebetween. The insulating layer 407 and the conductive layer 412b have an opening 441 that reaches the conductive layer 412a.

[0230] 14B, the conductive layers 412a and 412b have a single-layer structure, but this is not a limitation of one embodiment of the present invention. The conductive layers 412a and 412b can each have a stacked-layer structure.

[0231] The top surface shape of the opening 441 can be, for example, circular or elliptical. By making the top surface shape of the opening 441 circular, the processing accuracy when forming the opening 441 can be improved, and the opening 441 can be formed in a fine size. The top surface shape of the opening 441 can also be a polygon such as a triangle, a quadrangle (including a rectangle, a diamond, and a square), or a pentagon, or a polygon with rounded corners. The opening 441 can be formed using, for example, a resist mask.

[0232] The semiconductor layer 408 is provided to cover the opening 441. The semiconductor layer 408 has regions in contact with the top surface and side surfaces of the conductive layer 412b, the side surfaces of the insulating layer 407, and the top surface of the conductive layer 412a. The semiconductor layer 408 is electrically connected to the conductive layer 412a through the opening 441. The semiconductor layer 408 has a shape that follows the shapes of the top surface and side surfaces of the conductive layer 412b, the side surfaces of the insulating layer 407, and the top surface of the conductive layer 412a.

[0233] Of the semiconductor layer 408 provided along the side surface of the insulating layer 407, between the source electrode and the drain electrode, the entire region that overlaps with the gate electrode with the gate insulating layer interposed therebetween functions as a channel formation region. In addition, of the semiconductor layer 408, a region in contact with the source electrode functions as a source region, and a region in contact with the drain electrode functions as a drain region.

[0234] 14B and the like, the semiconductor layer 408 has a single-layer structure; however, one embodiment of the present invention is not limited to this. The semiconductor layer 408 can also have a stacked structure of two or more layers.

[0235] The insulating layer 406 functioning as a gate insulating layer of the transistor 210 is provided over the semiconductor layer 408 , the conductive layer 412 b , and the insulating layer 407 so as to cover the recessed portion resulting from the opening 441 .

[0236] The conductive layer 404e of the transistor 210 is provided over the insulating layer 406 so as to cover a recess resulting from the opening 441. Here, an insulating layer (not shown) is preferably provided over the conductive layer 404e and the insulating layer 406. An opening reaching the conductive layer 404e is provided in the insulating layer, and the conductive layer 404 functioning as a gate line is electrically connected to the conductive layer 404e through the opening.

[0237] In the opening 441, the conductive layer 404e has a region overlapping with the semiconductor layer 408 with the insulating layer 406 interposed therebetween. The conductive layer 404e also has a region overlapping with the conductive layer 412a and a region overlapping with the conductive layer 412b with the insulating layer 406 and the semiconductor layer 408 interposed therebetween. The conductive layer 404e preferably covers an end of the conductive layer 412b on the opening 441 side.

[0238] The transistor 210 is a so-called top-gate transistor having a gate electrode above the semiconductor layer 408. Furthermore, since the bottom surface of the semiconductor layer 408 is in contact with a source electrode or a drain electrode, the transistor 210 can be called a TGBC (Top Gate Bottom Contact) transistor.

[0239] The conductive layers 412a, 412b, and 404 can each function as a wiring, and the transistor 210 can be provided in a region where these wirings overlap. That is, in a circuit including the transistor 210 and the wiring, the area occupied by the transistor 210 and the wiring can be reduced. Therefore, the area occupied by the circuit can be reduced.

[0240] In the transistor of one embodiment of the present invention, the conductive layers 412a, 412b, and 404, which function as wirings, can be formed by processing different conductive films. Therefore, one or more other conductive layers can be arranged to overlap any one of the conductive layers, which increases the flexibility of the layout and enables the area occupied by the circuit to be reduced.

[0241] Next, a description will be given of the channel length and the channel width of the transistor 210. In the semiconductor layer 408, a region in contact with the conductive layer 412a functions as one of a source region and a drain region, a region in contact with the conductive layer 412b functions as the other of the source region and the drain region, and a region between the source region and the drain region functions as a channel formation region.

[0242] The channel length of the transistor 210 is the distance between the source region and the drain region. In Figure 14B, the channel length L210 of the transistor 210 is indicated by a dashed double-headed arrow. In a cross-sectional view, the channel length L210 is the distance between the end of the region where the semiconductor layer 408 and the conductive layer 412a contact each other and the end of the region where the semiconductor layer 408 and the conductive layer 412b contact each other.

[0243] In other words, the channel length L210 is determined by the film thickness of the insulating layer 407 and the angle between the side surface of the insulating layer 407 on the opening 441 side and the upper surface of the conductive layer 412a, and is not affected by the performance of the exposure equipment used to fabricate the transistor. Therefore, the channel length L210 can be set to a value smaller than the limit resolution of the exposure equipment, and a transistor with a fine size can be realized.

[0244] The on-state current of the transistor 210 can be increased by reducing the channel length L210. A circuit capable of high-speed operation can be manufactured by using the transistor 210. Furthermore, the transistor can be miniaturized, which enables the area occupied by the circuit to be reduced.

[0245] 14B and the like show a cross-sectional view in which the side surface of the insulating layer 407 on the opening 441 side has a straight line shape; however, one embodiment of the present invention is not limited to this. In the cross-sectional view, the side surface of the insulating layer 407 on the opening 441 side can have a curved line shape. Alternatively, the side surface can have both a straight line region and a curved line region.

[0246] The channel width of the transistor 210 is the width of the source region or the width of the drain region in a direction perpendicular to the channel length direction. That is, the channel width is the width of the region where the semiconductor layer 408 and the conductive layer 412a contact each other or the width of the region where the semiconductor layer 408 and the conductive layer 412b contact each other in a direction perpendicular to the channel length direction. Here, the channel width of the transistor 210 is described as the width of the region where the semiconductor layer 408 and the conductive layer 412b contact each other in a direction perpendicular to the channel length direction. In Figures 14A and 14B, the channel width W210 of the transistor 210 is indicated by a solid double-headed arrow. The channel width W210 is the length of the bottom end of the conductive layer 412b on the opening 441 side in a top view.

[0247] The channel width W210 is determined by the top surface shape of the opening 441. When the top surface shape of the opening 441 is circular, the diameter of the opening 441 is set to D441, and the film thickness of the conductive layer 412b is assumed to be negligible, then the channel width W210 can be calculated as "D441 × π".

[0248] That is, the transistor 210 has a large channel width relative to its occupied area. By increasing the channel width W210, the on-state current of the transistor 210 can be increased, and a circuit capable of high-speed operation can be manufactured.

[0249] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes and examples described in this specification.

[0250] 10: pixel, 15: pixel array, 20: housing, 21: circuit section, 22: secondary battery, 23: camera module, 23L: lens, 24: front panel, 24a: window section, 24b: frame section, 25: band, 26a: area, 26b: area, 30: solar cell, 31: opening, 40: display device, 50: electronic device, 50a: portable terminal, 50b: terminal, 60: external power supply, 70: sleeve, 101: layer, 110: substrate, 111b: pixel electrode, 111w: pixel electrode, 113_1: light-emitting unit, 113_2: light-emitting unit, 113_3: charge generating layer, 113b: layer, 113w: layer, 114: common layer, 117: common electrode, 118: mask layer, 119: FPC, 120: substrate, 122: adhesive layer, 125: insulating layer, 127: insulating layer, 130b: light emitting device, 130w: light emitting device, 131: protective layer, 135: light shielding layer, 136: light shielding layer, 137: color filter, 138: pixel circuit, 142b: conductive layer, 146b: conductive layer, 148: layer, 149b: conductive layer, 165: wiring, 166: conductive layer, 201: Transistor, 202: transistor, 203: transistor, 205: transistor, 206: transistor, 210: transistor, 211: insulating layer, 213: insulating layer, 214: insulating layer, 215: insulating layer, 218: insulating layer, 221: conductive layer, 222a: conductive layer, 222b: conductive layer, 223: conductive layer, 225: insulating layer, 230: connection portion, 231: semiconductor layer, 231i: channel formation region, 231n: low resistance region, 242: connection layer, 255a: insulating layer, 255b: insulating layer, 255c : insulating layer, 301: driving circuit, 303: driving circuit, 402: substrate, 404: conductive layer, 404e: conductive layer, 406: insulating layer, 407: insulating layer, 407a: insulating layer, 407b: insulating layer, 407c: insulating layer, 408: semiconductor layer, 412a: conductive layer, 412b: conductive layer, 441: opening, 500: photoelectric conversion layer, 500a: photoelectric conversion layer, 500b: photoelectric conversion layer, 510: layer, 520: layer, 530: layer, 540: electrode, 550: electrode, 560: substrate, 570: electrode, 570a: electrode, 570b: electrode

Claims

a pixel provided with a sub-pixel and a light-transmitting region; the light-transmitting region is disposed adjacent to the sub-pixel and has a function of transmitting light incident from outside; the subpixel has a light-emitting device in which a pixel electrode, a light-emitting layer, and a common electrode are stacked; the subpixel and the light-transmitting region have an insulating layer that is transparent to visible light, an end of the insulating layer is located above the pixel electrode; the insulating layer has a curved surface from the end portion to the light-transmitting region, A display device having an optical path in which light incident on the sub-pixel enters the light-transmitting region via the curved surface. 　 In claim 1, The light-emitting layer emits either red light, green light, or blue light. 　 In claim 1, the pixel electrode is reflective to visible light; The common electrode is transparent to visible light. 　 A display device comprising: the display device according to any one of claims 1 to 3; and a solar cell in which a plurality of cells are connected in series; The solar cell is disposed on the rear side of the display device. 　 In claim 4, The solar cell has a photoelectric conversion layer, and the photoelectric conversion layer has perovskite crystals. 　 In claim 4, a camera module having a lens; One cell of the solar cell has an opening, The electronic device is arranged so that the opening and the lens overlap. 　 In claim 4, the display device and the solar cell are housed in a watch-type housing; The plurality of cells are arranged in one direction, the housing has a first region and a second region facing the first region, a band is connected to the first region and the second region; The electronic device in which the first region and the second region are aligned in the same direction as the direction in which the plurality of cells are aligned. 　 A display device and a solar cell in which a plurality of cells are connected in series, the solar cell is disposed on the back surface side of the display device, the display device has a pixel provided with a first sub-pixel and a second sub-pixel; the first subpixel has a first light-emitting device having a first pixel electrode, a first light-emitting layer, and a common electrode; the second subpixel has a second light-emitting device having a second pixel electrode, a second light-emitting layer, and the common electrode; the first pixel electrode is reflective to visible light; the second pixel electrode and the common electrode are transparent to visible light; the first light-emitting layer and the second light-emitting layer each emit white light; The electronic device further comprises a color filter disposed on the first light-emitting device. 　 In claim 8, The solar cell has a photoelectric conversion layer, and the photoelectric conversion layer has perovskite crystals. 　 In claim 8, a camera module having a lens; One cell of the solar cell has an opening, The electronic device is arranged so that the opening and the lens overlap. 　 In claim 8, the display device and the solar cell are housed in a watch-type housing; The plurality of cells are arranged in one direction, the housing has a first region and a second region facing the first region, a band is connected to the first region and the second region; The electronic device in which the first region and the second region are aligned in the same direction as the direction in which the plurality of cells are aligned.

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