Optical device and electronic device

Abstract

The present invention provides an optical device which is thin and has high light utilization efficiency, and a compact electronic device which comprises the optical device. Provided is a thin optical device comprising a reflection / polarizing plate, a lens, and an optical rotator, said optical device using rotation of the plane of polarization of linearly polarized light by the optical rotator, and optical transmission and reflection properties of the reflection / polarizing plate, thereby making it possible to achieve a thin optical device with a short total length. Furthermore, the optical device does not use a half mirror and therefore makes it possible to achieve characteristics for high light utilization efficiency, reduce energy consumption by an electronic device, and improve reliability.

Description

Optical and electronic equipment

[0001] One aspect of the present invention relates to optical and electronic devices.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, an imaging device, and an operation method thereof or a manufacturing method thereof.

[0003] Note that in this specification and the like, a semiconductor device refers to any device that can function by utilizing semiconductor characteristics. A transistor and a semiconductor circuit are examples of a semiconductor device. In addition, a memory device, a display device, an imaging device, and an electronic device may include a semiconductor device.

[0004] 2. Description of the Related Art Goggle-type devices and eyeglass-type devices have been developed as electronic devices for virtual reality (VR) or augmented reality (AR).

[0005] Representative examples of display devices applicable to the display panel include display devices including liquid crystal elements, and display devices including organic EL (Electro Luminescence) elements or light-emitting diodes (LEDs: Light Emitting Diodes).

[0006] A display device equipped with an organic EL element does not require a backlight, which is necessary in a liquid crystal display device, and therefore can realize a thin, lightweight, high-contrast, and low-power display device. For example, an example of a display device using an organic EL element is described in Patent Document 1.

[0007] JP 2002-324673 A

[0008] Electronic devices such as goggle-type devices and eyeglass-type devices are types of wearable devices, and it is desirable to make them small and thin to improve portability and wearability. For this reason, thin optical devices designed to have a short focal length are used in such electronic devices.

[0009] However, such optical devices use half mirrors with low light utilization efficiency, necessitating the need to increase the brightness of the display device. Increasing the brightness of the display device increases power consumption and reduces the reliability of the display device. Therefore, there is a demand for thin optical devices with high light utilization efficiency.

[0010] Therefore, an object of one embodiment of the present invention is to provide a thin optical device with high light utilization efficiency, a small-sized electronic device including the optical device, an electronic device with low power consumption, or a novel electronic device.

[0011] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these will become apparent from the description of the specification, drawings, claims, etc., and it is possible to extract other problems from the description of the specification, drawings, claims, etc.

[0012] One embodiment of the present invention relates to a thin optical device with high light utilization efficiency, and an electronic device including the optical device.

[0013] One aspect of the present invention is an optical device having a first reflective polarizer, a first lens, an optical rotator, a second reflective polarizer, and a second lens, wherein the first reflective polarizer, the first lens, the optical rotator, the second reflective polarizer, and the second lens are arranged in this order so that they each have an overlapping area with each other, and the first lens and the optical rotator are spaced apart.

[0014] The first surface of the first reflective polarizer can be laminated to the first surface of the first lens.

[0015] A first surface of the polarization rotator can be bonded to a first surface of a second reflective polarizer, and a second surface of the second reflective polarizer opposite to the first surface can be bonded to a first surface of a second lens.

[0016] The first reflective polarizer transmits a first linearly polarized light and reflects a second linearly polarized light that is orthogonal to the first linearly polarized light, and the second reflective polarizer reflects a third linearly polarized light whose polarization plane is rotated 45° from the first linearly polarized light and transmits a fourth linearly polarized light that is orthogonal to the third linearly polarized light.

[0017] The optical rotator can have an optical rotation angle of 45°.

[0018] The first lens and the second lens may be convex lenses.

[0019] A polarizing plate may be provided facing a second surface opposite to the first surface of the first reflective polarizing plate.

[0020] Another aspect of the present invention is an electronic device having a display panel, a polarizing plate, a first reflective polarizing plate, a first lens, an optical rotator, a second reflective polarizing plate, and a second lens within a housing, wherein the display panel, polarizing plate, first reflective polarizing plate, first lens, optical rotator, second reflective polarizing plate, and second lens are arranged in that order so that each has an overlapping area with each other, the polarizing plate and the first reflective polarizing plate are arranged at a distance from each other, and the first lens and optical rotator are arranged at a distance from each other.

[0021] The display surface of the display panel can be attached to the first surface of the polarizing plate.

[0022] The first surface of the first reflective polarizer can be laminated to the first surface of the first lens.

[0023] A first surface of the polarization rotator can be bonded to a first surface of the second reflective polarizer, and a second surface of the second reflective polarizer opposite to the first surface can be bonded to a first surface of the second lens.

[0024] The polarizer can transmit a first linearly polarized light, the first reflective polarizer can transmit the first linearly polarized light and reflect a second linearly polarized light that is orthogonal to the first linearly polarized light, and the second reflective polarizer can reflect a third linearly polarized light whose polarization plane is rotated 45° from the first linearly polarized light and transmit a fourth linearly polarized light that is orthogonal to the third linearly polarized light.

[0025] The optical rotator may have an optical rotation angle of 45°.

[0026] The first lens and the second lens may be convex lenses.

[0027] According to one embodiment of the present invention, a thin optical device with high light utilization efficiency can be provided. Alternatively, a small-sized electronic device including the optical device can be provided. Alternatively, an electronic device with low power consumption can be provided. Alternatively, a novel electronic device can be provided.

[0028] 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.

[0029] FIG. 1 is a diagram illustrating a display device and an optical device. FIGS. 2A and 2B are diagrams illustrating an optical device. FIGS. 3A and 3B are diagrams illustrating an optical device. FIGS. 4A to 4G are diagrams illustrating an optical device. FIGS. 5A to 5C are diagrams illustrating an electronic device. FIGS. 6A and 6B are diagrams illustrating an eyeglass-type device. FIGS. 7A to 7C are diagrams illustrating an example of a configuration of a display panel. FIGS. 8A and 8B are diagrams illustrating an example of a configuration of a display panel. FIGS. 9A to 9F are diagrams illustrating an example of a configuration of a pixel. FIGS. 10A and 10B are diagrams illustrating an example of a configuration of a display panel. FIG. 11 is a diagram illustrating an example of a configuration of a display panel. FIG. 12 is a diagram illustrating an example of a configuration of a display panel. FIG. 13 is a diagram illustrating an example of a configuration of a display panel. FIG. 14 is a diagram illustrating an example of a configuration of a display panel. FIG. 15 is a diagram illustrating an example of a configuration of a display panel. FIG. 16 is a diagram illustrating an example of a configuration of a display panel. FIG. 17 is a diagram illustrating an example of a configuration of a display panel. 18A to 18F are diagrams illustrating an example of the configuration of a light-emitting device, and FIGS. 19A to 19C are diagrams illustrating an example of the configuration of a light-emitting device.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] Embodiment 1 In this embodiment, an optical device and an electronic device according to one embodiment of the present invention will be described.

[0034] One embodiment of the present invention is a thin optical device including a reflective polarizer, a lens, and a polarization rotator. The optical device can be made thin and have a short overall length by utilizing the rotation of the polarization plane of linearly polarized light by the polarization rotator and the light transmission and reflection characteristics of the reflective polarizer. Furthermore, the optical device of one embodiment of the present invention does not use a half mirror and therefore has high light utilization efficiency.

[0035] Electronic devices such as goggle-type devices or eyeglass-type devices have a structure in which a display device and an optical device are combined to widen the viewing angle. By using the optical device of one embodiment of the present invention in such electronic devices, the electronic devices can be small, thin, low in power consumption, and highly reliable.

[0036] Note that an optical device according to one embodiment of the present invention has a configuration in which a plurality of optical components are combined. Such a configuration housed in a housing is also simply called a lens. Alternatively, it may be called a pancake lens because of its thin shape.

[0037] 1 is a perspective view illustrating a display device and an optical device that can be used in an electronic device according to one embodiment of the present invention. A display device 30 and an optical device 40 are disposed separately from each other so as to have an overlapping region.

[0038] The user can view the image displayed on the display device 30 by bringing the eye 10 close to the optical device 40. The user can view the image with the viewing angle widened by the optical device 40, which gives the user a sense of immersion and realism.

[0039] The display device 30 has a configuration in which the display panel 31 and the polarizing plate 32 are arranged to have an overlapping area. For example, as shown in FIG. 1 , the display device 30 may have a configuration in which the polarizing plate 32 is attached to the display surface of the display panel 31.

[0040] The polarizing plate 32 does not have to be a component of the display device 30, and may be provided between the display device 30 (display panel 31) and the optical device 40. Alternatively, the polarizing plate 32 may be a component of the optical device 40, and may be disposed on the light incident surface side of the optical device 40.

[0041] The optical device 40 has an area where a reflective polarizer 41, a lens 42, an optical rotator 43, a reflective polarizer 44, and a lens 45 overlap one another. In the following description, the first surface refers to one surface of each element, and the second surface refers to the surface opposite to the first surface.

[0042] 1, a configuration may be adopted in which a first surface of a reflective polarizer 41 is bonded to a first surface of a lens 42. Alternatively, a configuration may be adopted in which a first surface of a reflective polarizer 44 is bonded to a first surface of an optical rotator 43, and a first surface of a lens 45 is bonded to a second surface of the reflective polarizer 44. Note that a configuration in which these elements are not bonded together but are arranged independently may also be adopted.

[0043] In order to ensure the necessary optical path length, it is preferable to arrange the lens 42 and the reflective polarizer 44 apart from each other. Therefore, when the optical rotator 43 and the reflective polarizer 44 are bonded together as described above, it is preferable to arrange the second surface of the lens 42 and the second surface of the optical rotator 43 apart from each other.

[0044] In addition, to bond the above-mentioned one element to the other element, an optical adhesive that has high transmittance for the wavelength of light to be used (for example, in the wavelength range of visible light) and does not absorb or have optical rotation properties for specific polarized light can be used. Alternatively, instead of bonding, one element may be formed by contacting the other element on top of the other element using a method such as coating.

[0045] 2A is a diagram illustrating the optical paths of a portion of an optical device according to one embodiment of the present invention, and the optical paths are indicated by dashed lines. For clarity, some elements that are shown adjacent to each other in FIG. 1 are shown separated from each other. Note that the effects of one embodiment of the present invention can also be achieved by arranging the elements as shown in FIG. 2A.

[0046] A portion of the light emitted from the display panel 31 passes through the polarizing plate 32, the reflective polarizing plate 41, the lens 42, and the optical rotator 43, and is reflected by the reflective polarizing plate 44. The light reflected by the reflective polarizing plate 44 passes through the optical rotator 43 and the lens 42, and is reflected again by the reflective polarizing plate 41. The light reflected by the reflective polarizing plate 41 passes through the lens 42, the optical rotator 43, the reflective polarizing plate 44, and the lens 45, and is incident on the eye 10.

[0047] By repeating reflection in this way, the optical path length can be ensured, and therefore an optical system with a short focal length can be obtained.

[0048] A liquid crystal panel having liquid crystal elements, an organic EL panel having organic EL elements, an LED panel having micro LEDs, or the like can be used as the display panel 31. In particular, it is preferable to use an organic EL panel which is self-luminous and can easily form a high-definition display unit.

[0049] The polarizing plate 32 can extract one linearly polarized light from light vibrating in all directions through 360°. In this embodiment, the description will be given assuming that the transmission axis of the polarizing plate 32 is 0°, but 0° is not an absolute value but a reference value. In other words, the polarization plane of the linearly polarized light extracted by the polarizing plate 32 is treated as 0°. Therefore, for example, 45° linearly polarized light means linearly polarized light in which the polarization plane of the linearly polarized light extracted by the polarizing plate 32 has been rotated by 45°.

[0050] The reflective polarizers 41 and 44 can transmit linearly polarized light that coincides with the transmission axis and reflect linearly polarized light that is orthogonal to the transmission axis. For example, a wire grid polarizer or a dielectric multilayer film can be used as the reflective polarizer.

[0051] Convex lenses can be used for the lenses 42 and 45. While FIG. 2A shows an example in which a biconvex lens is used for the lens 42 and a plano-convex lens is used for the lens 45, the present invention is not limited to this. For example, the lens 42 may be composed of a plurality of plano-convex lenses. Furthermore, the lens 45 may be a biconvex lens. Alternatively, the lenses 42 and 45 may be configured by combining lenses selected from biconvex lenses, plano-convex lenses, convex meniscus lenses, and concave meniscus lenses. Furthermore, lenses other than the lenses 42 and 45 may be provided.

[0052] The optical rotator 43 can rotate the plane of polarization of the incident linearly polarized light and emit it. In one embodiment of the present invention, an optical rotator having an optical rotation angle of 45° can be used as the optical rotator 43. As the optical rotator 43, a film-type cell in which twisted nematic liquid crystal is sealed, a polymer liquid crystal film filled with twisted nematic liquid crystal, a Faraday rotator, or the like can be used.

[0053] The polarization state in the optical path of the optical device according to one embodiment of the present invention will be described in detail with reference to Fig. 2B. Fig. 2B is an enlarged view of the display device 30 and the optical device 40 shown in Fig. 2A, in which the polarization state is shown in the upper optical path and the efficiency of light transmission or reflection in each element is shown in the lower optical path.

[0054] Light emitted from the display panel 31 and vibrating in all directions of 360° is incident on the polarizing plate 32. The transmission axis of the polarizing plate 32 is 0°, and 0° linearly polarized light is emitted from the polarizing plate 32.

[0055] The 0° linearly polarized light emitted from the polarizing plate 32 passes through the reflective polarizing plate 41 with a transmission axis of 0° and the lens 42, and is incident on the optical rotator 43. In the optical rotator 43, the polarization plane of the 0° linearly polarized light is rotated by 45°, and the light is emitted as 45° linearly polarized light.

[0056] The 45° linearly polarized light emitted from the optical rotator 43 is reflected by a reflective polarizer 44 with a reflection axis of 45°, and is again incident on the optical rotator 43. In the optical rotator 43, the polarization plane of the 45° linearly polarized light is rotated by 45°, and the light is emitted as 90° linearly polarized light.

[0057] The 90° linearly polarized light emitted from the optical rotator 43 is reflected by the reflective polarizer 41 with a reflection axis of 90°, and is again incident on the optical rotator 43. In the optical rotator 43, the polarization plane of the 90° linearly polarized light is rotated by 45°, and the light is emitted as 135° linearly polarized light.

[0058] The 135° linearly polarized light emitted from the optical rotator 43 is transmitted through the reflective polarizer 44 with a transmission axis of 135° and the lens 45. In this way, by using linearly polarized light and an optical rotator, it is possible to selectively reflect or transmit light at the reflective polarizer arranged on the optical path. Therefore, the optical path length can be ensured within a limited space, and the focal length of the optical device can be shortened.

[0059] Next, the light utilization efficiency will be explained. Note that the reflectance and transmittance of each element are assumed to be typical or ideal values.

[0060] When the amount of light emitted from the display panel 31 is 100%, the polarizing plate 32 absorbs light other than 0° linearly polarized light, so the light emitted from the polarizing plate 32 is generally about 40% (x 0.4).

[0061] Thereafter, transmission and reflection are repeated in each element arranged in the optical path, and because the transmittance and reflectance of each are ideally 100% (×1), approximately 40% of the light ultimately emerges from lens 45. In other words, in the optical device of one embodiment of the present invention, the loss of light other than at polarizing plate 32 is ideally zero, and it can be said that this is an optical device with high light utilization efficiency.

[0062] For comparison, an example of a conventional optical device is shown in FIG. 3A . Elements common to those in FIG. 2A are denoted by the same reference numerals. The optical device shown in FIG. 3A is similar to that shown in FIG. 2A in that it ensures an optical path length within a limited space by repeating reflection. The optical device shown in FIG. 3A differs from one embodiment of the present invention in that it uses a retardation plate 51, a half mirror 52, a retardation plate 53, and a reflective polarizer 54. The reflective polarizer 54 has a different reflection axis and transmission axis from those of the reflective polarizer 44.

[0063] Here, λ / 4 plates (¼ wavelength plates) are used as the retardation plates 51 and 53. When the retardation axis of the λ / 4 plate is set at 45° with respect to the transmission axis of the polarizing plate 32 at 0°, the retardation plate 51 and 53 are stacked together to produce right-handed circularly polarized light. The reflection axis of the reflective polarizing plate 54 is set at 0°, and the transmission axis is set at 90°.

[0064] The polarization state in the optical path of a conventional optical device will be described in detail with reference to Fig. 3B. Fig. 3B is an enlarged view of the display device 30 and optical device 40 shown in Fig. 3A, in which the polarization state is shown in the upper optical path and the efficiency of light transmission or reflection in each element is shown in the lower optical path.

[0065] Light emitted from the display panel 31 and vibrating in all directions of 360° is incident on the polarizing plate 32. The transmission axis of the polarizing plate 32 is 0°, and 0° linearly polarized light is emitted from the polarizing plate 32.

[0066] The 0° linearly polarized light emitted from the polarizing plate 32 is incident on the retardation plate 51 , where it is converted into right-handed circularly polarized light and emitted from the retardation plate 51 .

[0067] The right-handed circularly polarized light emitted from the phase difference plate 51 passes through the half mirror 52 and the lens 42 and is incident on the phase difference plate 53. The right-handed circularly polarized light incident on the phase difference plate 53 is converted into 0° linearly polarized light and is emitted from the phase difference plate 53.

[0068] The 0° linearly polarized light emitted from the retardation plate 53 is reflected by the reflective polarizer 54 with a reflection axis of 0° and enters the retardation plate 53 again. The 0° linearly polarized light that entered the retardation plate 53 becomes right-handed circularly polarized light and exits the retardation plate 53.

[0069] The right-handed circularly polarized light emitted from the retardation plate 53 is reflected by the half mirror 52, becomes left-handed circularly polarized light, and is incident on the retardation plate 53. The left-handed circularly polarized light incident on the retardation plate 53 becomes 90° linearly polarized light and is transmitted through the reflective polarizer 54 with a transmission axis of 90° and the lens 45.

[0070] Next, we will explain the light utilization efficiency. When the amount of light emitted from the display panel 31 is 100%, the light emitted from the polarizer 32 is approximately 40% (×0.4) because the polarizer 32 absorbs light other than 0° linearly polarized light.

[0071] Furthermore, since the transmittance of the retardation plate 51 is ideally 100% (×1), the light emitted from the retardation plate 51 is approximately 40% (40%×1).

[0072] Next, the light emitted from the phase difference plate 51 passes through the half mirror 52, but since the transmittance is about 50%, the amount of light after passing through the half mirror 52 is about 20% (40%×0.5).

[0073] The light that has passed through the half mirror 52 passes through the lens 42 and the phase difference plate 53, is reflected by the reflective polarizer 54, passes through the phase difference plate 53 and the lens 42, and reaches the half mirror 52 again to be reflected. If the transmittance of the lens 42 and the phase difference plate 53 and the reflectance of the reflective polarizer 54 are ideally 100% (×1) and the reflectance of the half mirror 52 is approximately 50%, the amount of light after reflection by the half mirror will be approximately 10% (20% × 0.5).

[0074] The light then passes through each element arranged in the optical path, and because the transmittance of each element is ideally 100% (x1), approximately 10% of the light ultimately emerges from lens 45. As described above, the light utilization efficiency of the optical device according to one embodiment of the present invention is approximately 40%, which can be said to be approximately four times that of conventional optical devices.

[0075] In conventional optical devices, light loss due to a half mirror is particularly large. In an optical device according to one embodiment of the present invention, a reflective polarizing plate is used instead of a half mirror. The reflective polarizing plate can achieve an ideal reflectance or transmittance of 100% for linearly polarized light, thereby reducing light loss.

[0076] Furthermore, since the optical device according to one embodiment of the present invention uses only linearly polarized light instead of circularly polarized light, a retardation plate is not required, which reduces the number of optical components constituting the optical device compared to conventional devices, and enables the optical device and electronic device to be manufactured at low cost.

[0077] 4A to 4D are diagrams showing modified examples of the arrangement or configuration of the polarizing plate 32, the reflective polarizing plate 41, and the lens 42. FIG.

[0078] 4A is a diagram showing a modified example of the arrangement of the reflective polarizer 41. The reflective polarizer 41 may be spaced apart from the lens 42 and arranged between the polarizer 32 and the lens 42. Alternatively, as shown in FIG. 4B , the polarizer 32 and the reflective polarizer 41 may be bonded together and arranged between the display panel 31 and the lens 42.

[0079] 4C shows a configuration in which the biconvex lens 42 is replaced with two single-convex lenses (lenses 42a and 42b). In this case, the reflective polarizer 41 can be sandwiched between the lenses 42a and 42b. Alternatively, as shown in FIG. 4D, the polarizer 32 and the reflective polarizer 41 may be bonded together and sandwiched between the lenses 42a and 42b.

[0080] 4E to 4G, a configuration may be adopted in which the polarizing plate 32 is not provided. Since the polarizing plate 32 and the reflective polarizing plate 41 both transmit 0° polarized light, the polarizing plate 32 may be omitted.

[0081] However, if the polarizing plate 32 is not present, when the light reflected by the reflective polarizing plate 41 returns to the display panel 31 and then travels back toward the reflective polarizing plate 41, the polarization state of some of the light may be disrupted and the light may end up passing through the reflective polarizing plate 41. This light may become stray light and degrade display quality. If the polarizing plate 32 is present, the light that has passed through the polarizing plate 32 will not be reflected by the reflective polarizing plate 41, and stray light can be suppressed.

[0082] 5A illustrates a display panel 31 included in an electronic device of one embodiment of the present invention. The display panel 31 includes a pixel array 74, a circuit 75, and a circuit 76. The pixel array 74 includes pixels 70 arranged in columns and rows.

[0083] The pixel 70 can have a plurality of sub-pixels 71. The sub-pixels 71 have the function of emitting light for display.

[0084] In this specification, the smallest unit within a single "pixel" that performs independent operation is defined as a "sub-pixel" for convenience in the explanation, but "pixel" may be replaced with "region" and "sub-pixel" may be replaced with "pixel".

[0085] The subpixel 71 has a light-emitting device that emits visible light. As the light-emitting device, it is preferable to use an EL element such as an OLED (organic light-emitting diode) or a QLED (quantum-dot light-emitting diode). Examples of light-emitting materials that the EL element may have include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence (TADF) materials, and inorganic compounds (such as quantum dot materials). Alternatively, an LED such as a micro LED (light-emitting diode) may be used as the light-emitting device.

[0086] The circuit 75 and the circuit 76 are driver circuits for driving the sub-pixel 71. The circuit 75 can function as a source driver circuit, and the circuit 76 can function as a gate driver circuit. The circuits 75 and 76 can be, for example, shift register circuits.

[0087] 5B , the circuit 75 and the circuit 76 may be provided in a layer 81, the pixel array 74 may be provided in a layer 82, and the layer 81 and the layer 82 may overlap with each other. With this structure, a display device with a narrow frame can be formed.

[0088] Furthermore, the wiring length can be shortened and the wiring capacitance can be reduced by providing the driver circuit below the pixel array 74. Therefore, a display panel that can operate at high speed and with low power consumption can be obtained.

[0089] 5B , by dividing the circuit 75 and the circuit 76, it is possible to drive parts of the pixel array 74. For example, it is possible to rewrite part of the image data of the pixel array 74. It is also possible to operate parts of the pixel array 74 at different operating frequencies.

[0090] 5B are merely examples and may be changed as appropriate. Part of the circuits 75 and 76 may be formed on the same layer as the pixel array 74. The layer 82 may also include circuits such as a memory circuit, an arithmetic circuit, and a communication circuit.

[0091] In this configuration, for example, a single crystal silicon substrate is used for the layer 81, the circuits 75 and 76 are formed using transistors having silicon in their channel formation regions (hereinafter referred to as Si transistors), and the pixel circuits included in the pixel array 74 provided in the layer 82 are formed using transistors having metal oxide in their channel formation regions (hereinafter referred to as OS transistors). The OS transistors can be formed as thin films and can be stacked on the Si transistors.

[0092] 5C , a layer 83 including an OS transistor may be provided between the layer 81 and the layer 82. In the layer 83, part of the pixel circuits included in the pixel array 74 can be formed using OS transistors. Alternatively, part of the circuits 75 and 76 can be formed using OS transistors. Alternatively, part of circuits such as a memory circuit, an arithmetic circuit, and a communication circuit that can be provided in the layer 82 can be formed using OS transistors.

[0093] 6A and 6B are diagrams showing an example of a glasses-type device having the display device 30 and optical device 40 shown in Fig. 1. Here, the combination of the display device 30 and the optical device 40 is shown by dashed lines as a display unit 35. The glasses-type device has two sets of display units 35, and may be called VR glasses or the like depending on the application.

[0094] The two display units 35 are incorporated into the housing 60 so that the surfaces of the lenses 45 are exposed on the inside. One display unit 35 is for the right eye, and the other display unit 35 is for the left eye, and by displaying an image corresponding to each eye on each display unit 35, the user can feel the three-dimensionality of the image.

[0095] Furthermore, the housing 60 or the band 61 may be provided with an input terminal and an output terminal. The input terminal can be connected to a cable that supplies a video signal from a video output device or the like, or power for charging a battery provided within the housing 60. The output terminal functions as, for example, an audio output terminal, and earphones, headphones, etc. can be connected. Note that if the configuration is such that audio data can be output via wireless communication, or if audio is output from an external video output device, the audio output terminal need not be provided.

[0096] Furthermore, a wireless communication module and a storage module may be provided inside the housing 60 or the band 61. The wireless communication module performs wireless communication, and the content to be viewed can be downloaded and stored in the storage module. This allows the user to view the downloaded content offline whenever they like.

[0097] Furthermore, a line-of-sight detection sensor may be provided inside the housing 60. For example, operation buttons such as power on, power off, sleep, volume adjustment, channel change, menu display, selection, decision, and back, as well as operation buttons such as video playback, stop, pause, fast forward, and fast rewind, can be displayed, and each operation can be performed by visually recognizing the operation button.

[0098] By using the optical device 40 of one embodiment of the present invention for a glasses-type device, the electronic device can be small, thin, low in power consumption, and highly reliable.

[0099] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0100] In this embodiment, a structure example of a display panel that can be applied to an electronic device of one embodiment of the present invention will be described. The display panel exemplified below can be applied to the display panel 31 in Embodiment 1.

[0101] One embodiment of the present invention is a display panel having light-emitting elements (also referred to as light-emitting devices). The display panel has two or more pixels that emit light of different colors. Each pixel has a light-emitting element. Each light-emitting element has a pair of electrodes and an EL layer therebetween. The light-emitting element is preferably an organic EL element (organic electroluminescent element). Two or more light-emitting elements that emit light of different colors each have an EL layer containing a different light-emitting material. For example, a full-color display panel can be realized by having three types of light-emitting elements that emit red (R), green (G), or blue (B) light, respectively.

[0102] When fabricating a display panel with multiple light-emitting elements that emit different colors of light, it is necessary to form at least one layer containing a light-emitting material (light-emitting layer) in an island shape. To fabricate part or all of the EL layer separately, a method for forming island-shaped organic films by vapor deposition using a shadow mask such as a metal mask is known. However, this method can result in deviations from the design in the shape and position of the island-shaped organic film due to various factors, such as the accuracy of the metal mask, misalignment between the metal mask and the substrate, metal mask deflection, and spreading of the contours of the deposited film due to vapor scattering, making it difficult to achieve high-resolution and high-aperture display panels. Furthermore, during vapor deposition, the contours of the layer can become blurred, resulting in thinning of the edges. In other words, the thickness of the island-shaped light-emitting layer can vary depending on the location. Furthermore, when fabricating large, high-resolution, or high-definition display panels, there is a concern that low dimensional accuracy of the metal mask and deformation due to heat can reduce manufacturing yield. Therefore, measures have been taken to artificially increase the resolution (also known as pixel density) by adopting special pixel arrangements such as a pentile array.

[0103] In this specification, the term "island-like" refers to a state in which two or more layers formed using the same material in the same process are physically separated. For example, an island-like light-emitting layer refers to a state in which the light-emitting layer is physically separated from an adjacent light-emitting layer.

[0104] In one embodiment of the present invention, an EL layer is processed into a fine pattern by photolithography without using a shadow mask such as a fine metal mask (FMM). This makes it possible to realize a display panel with high definition and a large aperture ratio, which have been difficult to achieve until now. Furthermore, because the EL layer can be individually fabricated, a display panel with extremely vivid images, high contrast, and high display quality can be realized. For example, the EL layer may be processed into a fine pattern using both a metal mask and photolithography.

[0105] Furthermore, the EL layer can be partially or entirely separated physically. This can suppress leakage current between adjacent light-emitting elements through a layer shared between the light-emitting elements (also referred to as a common layer). This can prevent crosstalk caused by unintended light emission, thereby realizing a display panel with extremely high contrast. In particular, a display panel with high current efficiency at low luminance can be realized.

[0106] One embodiment of the present invention can also be a display panel that combines a white-emitting light-emitting element and a color filter. In this case, light-emitting elements provided in pixels (subpixels) that emit light of different colors can have the same structure, and all layers can be common layers. Furthermore, part or all of each EL layer can be separated by a process using photolithography. This suppresses leakage current through the common layer, thereby achieving a display panel with high contrast. In particular, in an element having a tandem structure in which multiple light-emitting layers are stacked via a highly conductive intermediate layer, leakage current through the intermediate layer can be effectively prevented, thereby achieving a display panel that combines high brightness, high definition, and high contrast.

[0107] When the EL layer is processed using photolithography, a portion of the light-emitting layer may be exposed, which may cause deterioration. Therefore, it is preferable to provide an insulating layer that covers at least the side surfaces of the island-shaped light-emitting layer. The insulating layer may also be configured to cover a portion of the top surface of the island-shaped EL layer. The insulating layer is preferably made of a material that has barrier properties against water and oxygen. For example, an inorganic insulating film that is less likely to diffuse water or oxygen can be used. This suppresses deterioration of the EL layer and realizes a highly reliable display panel.

[0108] Furthermore, there is a region (recess) between two adjacent light-emitting elements where the EL layer of either light-emitting element is not provided. When a common electrode, or a common electrode and a common layer, is formed to cover the recess, a phenomenon in which the common electrode is separated by a step at the edge of the EL layer (also called a step discontinuity) may occur, resulting in insulation of the common electrode on the EL layer. Therefore, it is preferable to use a configuration in which the local step located between two adjacent light-emitting elements is filled with a resin layer functioning as a planarizing film (also called LFP: Local Filling Planarization). The resin layer functions as a planarizing film. This suppresses step discontinuity in the common layer or common electrode, thereby achieving a highly reliable display panel.

[0109] A more specific example of the structure of a display panel according to one embodiment of the present invention will be described below with reference to the drawings.

[0110] 7A is a schematic top view of a display panel 100 according to one embodiment of the present invention. The display panel 100 includes a plurality of light-emitting elements 110R that exhibit red light, a plurality of light-emitting elements 110G that exhibit green light, and a plurality of light-emitting elements 110B that exhibit blue light, over a substrate 101. In FIG. 7A, the light-emitting elements are labeled with R, G, and B within their light-emitting regions in order to easily distinguish them from one another.

[0111] The light-emitting elements 110R, 110G, and 110B are arranged in a matrix. Fig. 7A shows a so-called stripe arrangement, in which light-emitting elements of the same color are arranged in one direction. The arrangement of the light-emitting elements is not limited to this, and other arrangements such as an S-stripe arrangement, a delta arrangement, a Bayer arrangement, or a zigzag arrangement may also be used. Alternatively, a pentile arrangement or a diamond arrangement may also be used.

[0112] The light-emitting elements 110R, 110G, and 110B are preferably, for example, OLEDs or QLEDs. Examples of the light-emitting materials contained in the EL elements include fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF) materials. The light-emitting materials contained in the EL elements can be organic compounds or inorganic compounds (such as quantum dot materials).

[0113] 7A also shows a connection electrode 111C that is electrically connected to the common electrode 113. The connection electrode 111C is given a potential (e.g., an anode potential or a cathode potential) to be supplied to the common electrode 113. The connection electrode 111C is provided outside the display area where the light-emitting elements 110R and the like are arranged.

[0114] The connection electrode 111C can be provided along the periphery of the display area. For example, it may be provided along one side of the periphery of the display area, or it may be provided over two or more sides of the periphery of the display area. That is, when the top surface shape of the display area is rectangular, the top surface shape of the connection electrode 111C can be a strip shape (rectangle), an L-shape, a U-shape (square bracket shape), a square shape, or the like.

[0115] 7B and 7C are schematic cross-sectional views corresponding to dashed dotted lines A1-A2 and A3-A4 in Fig. 7A, respectively. Fig. 7B shows a schematic cross-sectional view of light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B, and Fig. 7C shows a schematic cross-sectional view of connection portion 140 where connection electrode 111C and common electrode 113 are connected.

[0116] The light-emitting element 110R has a pixel electrode 111R, an organic layer 112R, a common layer 114, and a common electrode 113. The light-emitting element 110G has a pixel electrode 111G, an organic layer 112G, a common layer 114, and a common electrode 113. The light-emitting element 110B has a pixel electrode 111B, an organic layer 112B, a common layer 114, and a common electrode 113. The common layer 114 and the common electrode 113 are provided in common to the light-emitting element 110R, the light-emitting element 110G, and the light-emitting element 110B.

[0117] The organic layer 112R of the light-emitting element 110R contains a light-emitting organic compound that emits at least red light. The organic layer 112G of the light-emitting element 110G contains a light-emitting organic compound that emits at least green light. The organic layer 112B of the light-emitting element 110B contains a light-emitting organic compound that emits at least blue light. The organic layer 112R, the organic layer 112G, and the organic layer 112B can also be called EL layers, and each contains at least a layer containing a light-emitting substance (light-emitting layer).

[0118] Hereinafter, when describing matters common to light emitting element 110R, light emitting element 110G, and light emitting element 110B, they may be referred to as light emitting element 110. Similarly, when describing matters common to components distinguished by alphabets, such as organic layer 112R, organic layer 112G, and organic layer 112B, they may be described using symbols without the alphabets.

[0119] The organic layer 112 and the common layer 114 can each independently have one or more of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. For example, the organic layer 112 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 111 side, and the common layer 114 can have an electron injection layer.

[0120] The pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B are provided for each light-emitting element. The common electrode 113 and common layer 114 are provided as a continuous layer common to each light-emitting element. A conductive film transmissive to visible light is used for either the pixel electrode or the common electrode 113, and a conductive film reflective to visible light is used for the other. By making each pixel electrode transmissive and the common electrode 113 reflective, a bottom-emission display panel can be achieved. Conversely, by making each pixel electrode reflective and the common electrode 113 transmissive, a top-emission display panel can be achieved. Note that by making both the pixel electrodes and the common electrode 113 transmissive, a dual-emission display panel can be achieved.

[0121] A protective layer 121 is provided on the common electrode 113 to cover the light emitting elements 110R, 110G, and 110B. The protective layer 121 has a function of preventing impurities such as water from diffusing from above into each light emitting element.

[0122] The edge of the pixel electrode 111 preferably has a tapered shape. When the edge of the pixel electrode 111 has a tapered shape, the organic layer 112 provided along the edge of the pixel electrode 111 can also have a tapered shape. By tapering the edge of the pixel electrode 111, the coverage of the organic layer 112 provided over the edge of the pixel electrode 111 can be improved. Furthermore, by tapering the side surface of the pixel electrode 111, foreign matter (for example, also referred to as dust or particles) during the manufacturing process can be easily removed by a process such as cleaning, which is preferable.

[0123] In this specification and the like, the term "tapered shape" refers to a shape in which at least a part of a side surface of a structure is inclined with respect to a substrate surface. For example, it is preferable that the structure has a region in which the angle between the inclined side surface and the substrate surface (also referred to as the taper angle) is less than 90°.

[0124] The organic layer 112 is processed into an island shape using photolithography. As a result, the angle between the top surface and the side surface of the organic layer 112 at its edge is close to 90 degrees. On the other hand, an organic film formed using FMM (Fine Metal Mask) or the like tends to become gradually thinner closer to the edge. For example, the top surface is formed in a sloped shape over a range of 1 μm to 10 μm, making it difficult to distinguish between the top surface and the side surface.

[0125] Between two adjacent light emitting elements, there are an insulating layer 125, a resin layer 126 and a layer 128.

[0126] Between two adjacent light-emitting elements, the side surfaces of the organic layers 112 face each other with the resin layer 126 sandwiched therebetween. The resin layer 126 is located between the two adjacent light-emitting elements and is provided so as to fill the ends of each organic layer 112 and the region between the two organic layers 112. The resin layer 126 has a smooth, convex upper surface, and a common layer 114 and a common electrode 113 are provided to cover the upper surface of the resin layer 126.

[0127] The resin layer 126 functions as a planarization film that fills in a step located between two adjacent light-emitting elements. By providing the resin layer 126, it is possible to prevent a phenomenon (also called step disconnection) in which the common electrode 113 is divided by a step at the end of the organic layer 112, and the common electrode on the organic layer 112 is isolated. The resin layer 126 can also be called LFP (Local Filling Planarization).

[0128] An insulating layer containing an organic material can be suitably used as the resin layer 126. For example, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin, precursors of these resins, etc. can be used as the resin layer 126. Alternatively, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used as the resin layer 126.

[0129] Furthermore, a photosensitive resin can be used as the resin layer 126. A photoresist can be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0130] The resin layer 126 may contain a material that absorbs visible light. For example, the resin layer 126 itself may be made of a material that absorbs visible light, or the resin layer 126 may contain a pigment that absorbs visible light. For example, the resin layer 126 may be a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light, or a resin that contains carbon black as a pigment and functions as a black matrix.

[0131] The insulating layer 125 is provided in contact with the side surface of the organic layer 112. The insulating layer 125 is also provided to cover the upper end portion of the organic layer 112. A portion of the insulating layer 125 is provided in contact with the upper surface of the substrate 101.

[0132] The insulating layer 125 is located between the resin layer 126 and the organic layer 112, and functions as a protective film to prevent the resin layer 126 from contacting the organic layer 112. If the organic layer 112 and the resin layer 126 come into contact with each other, the organic layer 112 may be dissolved by an organic solvent or the like used when forming the resin layer 126. Therefore, by providing the insulating layer 125 between the organic layer 112 and the resin layer 126, it is possible to protect the side surfaces of the organic layer 112.

[0133] 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 may have a single-layer structure or a stacked-layer structure. Examples of oxide insulating films include a silicon oxide film, an aluminum oxide film, a magnesium oxide film, an indium gallium zinc oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, and a tantalum oxide film. Examples of nitride insulating films include a silicon nitride film and an aluminum nitride film. Examples of oxynitride insulating films include a silicon oxynitride film and an aluminum oxynitride film. Examples of nitride oxide insulating films include a silicon nitride oxide film and an aluminum nitride oxide film. In particular, by using an inorganic insulating film such as a metal oxide film, an aluminum oxide film, or a silicon oxide film formed by an ALD method as the insulating layer 125, an insulating layer 125 with few pinholes and excellent protection of the EL layer can be formed.

[0134] In this specification and elsewhere, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. 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.

[0135] The insulating layer 125 can be formed by a sputtering method, a CVD method, a PLD method, an ALD method, or the like. The insulating layer 125 is preferably formed by an ALD method because it has good coverage.

[0136] Furthermore, a reflective film (e.g., a metal film containing one or more selected from silver, palladium, copper, titanium, aluminum, etc.) may be provided between the insulating layer 125 and the resin layer 126, so that the light emitted from the light-emitting layer is reflected by the reflective film, thereby improving the light extraction efficiency.

[0137] The layer 128 is a remaining portion of a protective layer (also referred to as a mask layer or a sacrificial layer) for protecting the organic layer 112 during etching of the organic layer 112. The layer 128 can be made of a material that can be used for the insulating layer 125. In particular, it is preferable to use the same material for the layer 128 and the insulating layer 125 because a common processing device or the like can be used for both.

[0138] In particular, inorganic insulating films such as metal oxide films such as aluminum oxide films and hafnium oxide films, or silicon oxide films formed by the ALD method have few pinholes and therefore have an excellent function of protecting the EL layer, and can be suitably used for the insulating layer 125 and the layer 128.

[0139] The protective layer 121 may have, for example, a single-layer structure or a stacked structure including at least an inorganic insulating film. Examples of the inorganic insulating film include oxide films or nitride films such as a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, an aluminum oxynitride film, and a hafnium oxide film. Alternatively, the protective layer 121 may be made of a semiconductor material or a conductive material such as indium gallium oxide, indium zinc oxide, indium tin oxide, or indium gallium zinc oxide.

[0140] The protective layer 121 may also be a laminated film of an inorganic insulating film and an organic insulating film. For example, a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films is preferable. Furthermore, it is preferable that the organic insulating film functions as a planarizing film. This allows the upper surface of the organic insulating film to be flat, improving the coverage of the inorganic insulating film thereon and enhancing the barrier properties. Furthermore, since the upper surface of the protective layer 121 is flat, when a structure (e.g., a color filter, a touch sensor electrode, a lens array, etc.) is provided above the protective layer 121, the influence of uneven shapes caused by the structure below can be reduced, which is preferable.

[0141] 7C shows a connection portion 140 where the connection electrode 111C and the common electrode 113 are electrically connected. In the connection portion 140, an opening is provided in the insulating layer 125 and the resin layer 126 above the connection electrode 111C. The connection electrode 111C and the common electrode 113 are electrically connected through the opening.

[0142] 7C shows the connection portion 140 where the connection electrode 111C and the common electrode 113 are electrically connected, but the common electrode 113 may be provided on the connection electrode 111C via the common layer 114. In particular, when a carrier injection layer is used for the common layer 114, the electrical resistivity of the material used for the common layer 114 is sufficiently low and the common layer 114 can be formed thin, so that there is often no problem even if the common layer 114 is located at the connection portion 140. This allows the common electrode 113 and the common layer 114 to be formed using the same masking mask, thereby reducing manufacturing costs.

[0143] [Configuration Example 2] The following describes a display panel having a configuration that is partially different from that of the above-described configuration example 1. Note that parts common to the above-described configuration example 1 will be referred to, and descriptions thereof may be omitted.

[0144] 8A shows a schematic cross-sectional view of the display panel 100a. The display panel 100a differs from the display panel 100 mainly in that the light-emitting elements have a different configuration and that the display panel 100a has colored layers.

[0145] The display panel 100a includes a light-emitting element 110W that emits white light. The light-emitting element 110W includes a pixel electrode 111, an organic layer 112W, a common layer 114, and a common electrode 113. The organic layer 112W emits white light. For example, the organic layer 112W may be configured to include two or more light-emitting materials whose emitted light colors are complementary to each other. For example, the organic layer 112W may be configured to include a light-emitting organic compound that emits red light, a light-emitting organic compound that emits green light, and a light-emitting organic compound that emits blue light. Alternatively, the organic layer 112W may be configured to include a light-emitting organic compound that emits blue light and a light-emitting organic compound that emits yellow light.

[0146] The organic layers 112W are separated between two adjacent light-emitting elements 110W. This makes it possible to suppress leakage current flowing between adjacent light-emitting elements 110W via the organic layers 112W, thereby suppressing crosstalk caused by the leakage current. As a result, a display panel with high contrast and color reproducibility can be realized.

[0147] An insulating layer 122 that functions as a planarizing film is provided on the protective layer 121, and a coloring layer 116R, a coloring layer 116G, and a coloring layer 116B are provided on the insulating layer 122.

[0148] The insulating layer 122 can be an organic resin film or an inorganic insulating film with a flattened upper surface. The insulating layer 122 forms the surface on which the colored layers 116R, 116G, and 116B are formed, and therefore, a flat upper surface of the insulating layer 122 allows the thickness of the colored layers 116R and the like to be uniform, thereby improving color purity. However, if the thickness of the colored layers 116R and the like is uneven, the amount of light absorption varies depending on the location of the colored layer 116R, which may result in a decrease in color purity.

[0149] Configuration Example 3 FIG. 8B shows a schematic cross-sectional view of a display panel 100b.

[0150] The light-emitting element 110R has a pixel electrode 111, a conductive layer 115R, an organic layer 112W, and a common electrode 113. The light-emitting element 110G has a pixel electrode 111, a conductive layer 115G, an organic layer 112W, and a common electrode 113. The light-emitting element 110B has a pixel electrode 111, a conductive layer 115B, an organic layer 112W, and a common electrode 113. The conductive layer 115R, the conductive layer 115G, and the conductive layer 115B each have light-transmitting properties and function as an optical adjustment layer.

[0151] A microresonator (microcavity) structure can be realized by using a film that reflects visible light for the pixel electrode 111 and a film that is both reflective and transparent to visible light for the common electrode 113. In this case, by adjusting the thicknesses of the conductive layers 115R, 115G, and 115B so as to provide optimal optical path lengths, even when the organic layer 112 that emits white light is used, light of different wavelengths that are intensified can be obtained from the light-emitting elements 110R, 110G, and 110B.

[0152] Furthermore, colored layers 116R, 116G, and 116B are provided on the optical paths of the light emitting elements 110R, 110G, and 110B, respectively, so that light with high color purity can be obtained.

[0153] An insulating layer 123 is also provided to cover the edges of the pixel electrode 111 and the optical adjustment layer 115. The insulating layer 123 preferably has tapered edges. Providing the insulating layer 123 can improve coverage by the organic layer 112W, the common electrode 113, the protective layer 121, and the like that are formed thereon.

[0154] The organic layer 112W and the common electrode 113 are each provided as a continuous film common to each light-emitting element, which is preferable because it can greatly simplify the manufacturing process of the display panel.

[0155] Here, it is preferable that the edge of the pixel electrode 111 has a shape that is nearly vertical. This allows a steeply inclined portion to be formed on the surface of the insulating layer 123, and it is possible to form a thin portion in a part of the organic layer 112W that covers this portion, or to divide a part of the organic layer 112W. Therefore, it is possible to suppress leakage current that occurs through the organic layer 112W between adjacent light-emitting elements without processing the organic layer 112W using a photolithography method or the like.

[0156] The above is a description of an example of the configuration of the display panel.

[0157] [Pixel Layout] The following mainly describes pixel layouts that are different from that shown in Fig. 7A. There are no particular limitations on the arrangement of light-emitting elements (sub-pixels), and various methods can be applied.

[0158] Examples of the top surface shape of the sub-pixel include a triangle, a quadrangle (including a rectangle and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, a circle, etc. Here, the top surface shape of the sub-pixel corresponds to the top surface shape of the light-emitting region of the light-emitting element.

[0159] An S-stripe arrangement is applied to the pixel 150 shown in Fig. 9A. The pixel 150 shown in Fig. 9A is composed of three sub-pixels, namely, light-emitting elements 110a, 110b, and 110c. For example, the light-emitting element 110a may be a blue light-emitting element, the light-emitting element 110b may be a red light-emitting element, and the light-emitting element 110c may be a green light-emitting element.

[0160] The pixel 150 shown in FIG. 9B includes a light-emitting element 110a having a generally trapezoidal or triangular top surface shape with rounded corners, a light-emitting element 110b having a generally trapezoidal or triangular top surface shape with rounded corners, and a light-emitting element 110c having a generally rectangular or hexagonal top surface shape with rounded corners. Furthermore, the light-emitting element 110a has a larger light-emitting area than the light-emitting element 110b. In this manner, the shape and size of each light-emitting element can be determined independently. For example, the more reliable the light-emitting element, the smaller the size can be. For example, the light-emitting element 110a may be a green light-emitting element, the light-emitting element 110b may be a red light-emitting element, and the light-emitting element 110c may be a blue light-emitting element.

[0161] The pixels 124a and 124b shown in Fig. 9C are arranged in a Pentile arrangement. Fig. 9C shows an example in which a pixel 124a having light-emitting elements 110a and 110b and a pixel 124b having light-emitting elements 110b and 110c are arranged alternately. For example, the light-emitting element 110a may be a red light-emitting element, the light-emitting element 110b may be a green light-emitting element, and the light-emitting element 110c may be a blue light-emitting element.

[0162] 9D and 9E are arranged in a delta configuration. The pixel 124a has two light-emitting elements (light-emitting elements 110a and 110b) in the top row (first row) and one light-emitting element (light-emitting element 110c) in the bottom row (second row). The pixel 124b has one light-emitting element (light-emitting element 110c) in the top row (first row) and two light-emitting elements (light-emitting elements 110a and 110b) in the bottom row (second row). For example, the light-emitting element 110a may be a red light-emitting element, the light-emitting element 110b may be a green light-emitting element, and the light-emitting element 110c may be a blue light-emitting element.

[0163] FIG. 9D shows an example in which each light-emitting element has a substantially rectangular top surface shape with rounded corners, and FIG. 9E shows an example in which each light-emitting element has a circular top surface shape.

[0164] 9F shows an example in which light-emitting elements of each color are arranged in a zigzag pattern. Specifically, when viewed from above, the positions of the upper edges of two light-emitting elements arranged in a column (e.g., light-emitting elements 110a and 110b, or light-emitting elements 110b and 110c) are offset. For example, light-emitting element 110a may be a red light-emitting element, light-emitting element 110b may be a green light-emitting element, and light-emitting element 110c may be a blue light-emitting element.

[0165] In photolithography, the finer the pattern to be processed, the more significant the effect of light diffraction becomes. This reduces the fidelity of the photomask pattern when it is transferred by exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, it is likely to have rounded corners. As a result, the top surface shape of the light-emitting element may be polygonal with rounded corners, elliptical, circular, or the like.

[0166] Furthermore, in a method for manufacturing a display panel according to one embodiment of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the material for the EL layer and the curing temperature of the resist material, the resist film may not be cured sufficiently. A resist film that is not cured sufficiently may have a shape that deviates from the desired shape during processing. As a result, the top surface shape of the EL layer may become a polygon with rounded corners, an ellipse, a circle, or the like. For example, when a resist mask with a square top surface shape is formed, a resist mask with a circular top surface shape may be formed, resulting in a circular top surface shape of the EL layer.

[0167] In order to form the top surface of the EL layer into a desired shape, a technique for correcting a mask pattern in advance (OPC (Optical Proximity Correction) technique) may be used so that the design pattern and the transfer pattern coincide with each other. Specifically, the OPC technique adds a correction pattern to the corners of figures on the mask pattern.

[0168] This concludes the description of the pixel layout.

[0169] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0170] Embodiment 3 In this embodiment, another structural example of a display panel that can be applied to an electronic device of one embodiment of the present invention will be described.

[0171] The display panel of this embodiment is a high-definition display panel, and is particularly suitable for use as the display section of VR devices such as head-mounted displays, and wearable devices that can be worn on the head, such as glasses-type AR devices.

[0172] 10A shows a perspective view of a display module 280. The display module 280 has a display panel 200A and an FPC 290. Note that the display panel included in the display module 280 is not limited to the display panel 200A, and may be any of the display panels 200B to 200F described below.

[0173] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display unit 281. The display unit 281 is an area for displaying an image.

[0174] 10B is a perspective view schematically illustrating the configuration on the substrate 291 side. A circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked on the substrate 291. A terminal portion 285 for connecting to the FPC 290 is provided in a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 composed of a plurality of wirings.

[0175] The pixel section 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of Fig. 10B. The pixel 284a has a light-emitting element 110R that emits red light, a light-emitting element 110G that emits green light, and a light-emitting element 110B that emits blue light.

[0176] The pixel circuit portion 283 has a plurality of pixel circuits 283a arranged periodically. Each pixel circuit 283a is a circuit that controls the light emission of three light-emitting devices included in one pixel 284a. One pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting device. For example, the pixel circuit 283a may be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitor for each light-emitting device. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to the source. This realizes an active matrix display panel.

[0177] The circuit portion 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like. Furthermore, a transistor provided in the circuit portion 282 may constitute a part of the pixel circuit 283a. That is, the pixel circuit 283a may be composed of a transistor included in the pixel circuit portion 283 and a transistor included in the circuit portion 282.

[0178] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, etc. from the outside to the circuit portion 282. An IC may be mounted on the FPC 290.

[0179] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are provided overlapping the pixel unit 284, thereby enabling the aperture ratio (effective display area ratio) of the display unit 281 to be extremely high. For example, the aperture ratio of the display unit 281 can be 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. Furthermore, the pixels 284a can be arranged at an extremely high density, enabling the resolution of the display unit 281 to be extremely high. For example, it is preferable that the pixels 284a be arranged in the display unit 281 at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20,000 ppi or less, or 30,000 ppi or less.

[0180] Because such a display module 280 has extremely high resolution, it can be suitably used in VR devices such as head-mounted displays, or in glasses-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display unit 281, so even when the display unit is enlarged with lenses, the pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 280 is not limited to this, and can be suitably used in electronic devices with relatively small display units. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0181] [Display Panel 200A] The display panel 200A shown in FIG. 11 includes a substrate 301, light-emitting elements 110R, 110G, and 110B, a capacitor 240, and a transistor 310.

[0182] Substrate 301 corresponds to substrate 291 in FIGS. 10A and 10B.

[0183] The transistor 310 has a channel formation region in a substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities and functions as one of a source and a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0184] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0185] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0186] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located therebetween. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as a dielectric of the capacitor 240.

[0187] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain of the transistor 310 by a plug 271 buried in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0188] An insulating layer 255a is provided to cover the capacitor 240, an insulating layer 255b is provided over the insulating layer 255a, and an insulating layer 255c is provided over the insulating layer 255b.

[0189] An inorganic insulating film can be preferably used for each of the insulating layers 255a, 255b, and 255c. For example, it is preferable to use a silicon oxide film for the insulating layer 255a and the insulating layer 255c, and a silicon nitride film for the insulating layer 255b. This allows the insulating layer 255b to function as an etching protection film. In this embodiment, an example is shown in which part of the insulating layer 255c is etched to form a recess, but the insulating layer 255c does not necessarily have to have a recess.

[0190] The light-emitting elements 110R, 110G, and 110B are provided over the insulating layer 255c. Embodiment 1 can be referred to for the structures of the light-emitting elements 110R, 110G, and 110B.

[0191] The display panel 200A has a separate light-emitting device for each emitted color, so there is little change in chromaticity between low-luminance and high-luminance emission. Furthermore, because the organic layers 112R, 112G, and 112B are spaced apart from one another, crosstalk between adjacent subpixels can be suppressed even in a high-resolution display panel. This makes it possible to realize a high-resolution display panel with high display quality.

[0192] In the region between adjacent light emitting elements, an insulating layer 125, a resin layer 126, and a layer 128 are provided.

[0193] The pixel electrodes 111R, 111G, and 111B of the light-emitting element are electrically connected to one of the source and drain of the transistor 310 via a plug 256 embedded in the insulating layers 255a, 255b, and 255c, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. The height of the top surface of the insulating layer 255c and the height of the top surface of the plug 256 are the same or approximately the same. Various conductive materials can be used for the plug.

[0194] A protective layer 121 is provided on the light emitting elements 110R, 110G, and 110B. A substrate 170 is attached to the protective layer 121 with an adhesive layer 171.

[0195] There is no insulating layer covering the upper end of each pixel electrode 111 between two adjacent pixel electrodes 111. This allows the distance between adjacent light-emitting elements to be extremely narrow, resulting in a high-definition or high-resolution display panel.

[0196] 12 has a stacked structure of a transistor 310A and a transistor 310B, each of which has a channel formed in a semiconductor substrate. Note that in the following description of the display panel, descriptions of parts that are the same as those of the display panel described above may be omitted.

[0197] The display panel 200B has a structure in which a substrate 301B provided with a transistor 310B, a capacitor 240, and a light-emitting device and a substrate 301A provided with a transistor 310A are bonded together.

[0198] Here, an insulating layer 345 is provided on the lower surface of the substrate 301B, and an insulating layer 346 is provided on the insulating layer 261 provided on the substrate 301A. The insulating layers 345 and 346 function as protective layers and can suppress the diffusion of impurities into the substrates 301B and 301A. The insulating layers 345 and 346 can be made of an inorganic insulating film that can be used for the protective layer 121.

[0199] The substrate 301B is provided with a plug 343 that penetrates the substrate 301B and an insulating layer 345. Here, it is preferable to provide an insulating layer 344 that covers the side surface of the plug 343 and functions as a protective layer.

[0200] Furthermore, in the substrate 301B, a conductive layer 342 is provided below the insulating layer 345. The conductive layer 342 is embedded in the insulating layer 335, and the lower surfaces of the conductive layer 342 and the insulating layer 335 are flattened. The conductive layer 342 is electrically connected to a plug 343.

[0201] On the other hand, in the substrate 301A, a conductive layer 341 is provided on an insulating layer 346. The conductive layer 341 is embedded in the insulating layer 336, and the upper surfaces of the conductive layer 341 and the insulating layer 336 are flattened.

[0202] It is preferable to use the same conductive material for the conductive layers 341 and 342. For example, a metal film containing an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, or a metal nitride film containing the above elements (titanium nitride film, molybdenum nitride film, tungsten nitride film), etc., can be used. In particular, it is preferable to use copper for the conductive layers 341 and 342. This allows for the application of Cu-Cu (copper-copper) direct bonding technology (technology that achieves electrical conductivity by connecting Cu (copper) pads together).

[0203] [Display Panel 200C] The display panel 200C shown in FIG. 13 has a configuration in which a conductive layer 341 and a conductive layer 342 are bonded via a bump 347.

[0204] 13 , by providing a bump 347 between the conductive layer 341 and the conductive layer 342, the conductive layer 341 and the conductive layer 342 can be electrically connected. The bump 347 can be formed using a conductive material containing, for example, gold (Au), nickel (Ni), indium (In), tin (Sn), or the like. Alternatively, for example, solder may be used as the bump 347. An adhesive layer 348 may be provided between the insulating layer 345 and the insulating layer 346. When the bump 347 is provided, the insulating layer 335 and the insulating layer 336 may not be provided.

[0205] [Display Panel 200D] The display panel 200D shown in FIG. 14 differs from the display panel 200A mainly in the configuration of the transistors.

[0206] The transistor 320 is a transistor (OS transistor) in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

[0207] The transistor 320 includes a semiconductor layer 321 , an insulating layer 323 , a conductive layer 324 , a pair of conductive layers 325 , an insulating layer 326 , and a conductive layer 327 .

[0208] Substrate 331 corresponds to substrate 291 in FIGS. 10A and 10B.

[0209] An insulating layer 332 is provided over a substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320 and prevents oxygen from being released from the semiconductor layer 321 toward the insulating layer 332. The insulating layer 332 can be, for example, a film through which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0210] A conductive layer 327 is provided over the insulating layer 332, and an insulating layer 326 is provided to cover the conductive layer 327. The conductive layer 327 functions as a first gate electrode of the transistor 320, and part of the insulating layer 326 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a portion of the insulating layer 326 that is in contact with the semiconductor layer 321. The top surface of the insulating layer 326 is preferably planarized.

[0211] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide (also referred to as an oxide semiconductor) film exhibiting semiconductor characteristics. A pair of conductive layers 325 is provided on and in contact with the semiconductor layer 321 and functions as a source electrode and a drain electrode.

[0212] An insulating layer 328 is provided to cover top surfaces and side surfaces of the pair of conductive layers 325 and side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided over the insulating layer 328. The insulating layer 328 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 264 or the like into the semiconductor layer 321 and prevents oxygen from being released from the semiconductor layer 321. The insulating layer 328 can be an insulating film similar to the insulating layer 332.

[0213] An opening reaching the semiconductor layer 321 is provided in the insulating layer 328 and the insulating layer 264. An insulating layer 323 in contact with the top surface of the semiconductor layer 321 and a conductive layer 324 are buried in the opening. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0214] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are the same or approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0215] The insulating layer 264 and the insulating layer 265 function as interlayer insulating layers. The insulating layer 329 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 265 or the like to the transistor 320. The insulating layer 329 can be formed using an insulating film similar to the insulating layer 328 and the insulating layer 332.

[0216] A plug 274 electrically connected to one of the pair of conductive layers 325 is provided so as to be embedded in the insulating layer 265, the insulating layer 329, and the insulating layer 264. Here, the plug 274 preferably has a conductive layer 274a covering the side surfaces of the openings of the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328 and a part of the upper surface of the conductive layer 325, and a conductive layer 274b in contact with the upper surface of the conductive layer 274a. In this case, it is preferable to use a conductive material through which hydrogen and oxygen do not easily diffuse as the conductive layer 274a.

[0217] Note that the structure of the transistor included in the display panel of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Furthermore, either a top-gate transistor or a bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0218] The transistor 320 has a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates may be connected and the transistor may be driven by supplying the same signal to them. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential for controlling the threshold voltage to one of the two gates and a potential for driving to the other.

[0219] The crystallinity of a semiconductor material used for a semiconductor layer of a transistor is not particularly limited, and any of an amorphous semiconductor, a single-crystal semiconductor, and a semiconductor having crystallinity other than single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single-crystal semiconductor or a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0220] The band gap of the metal oxide used for the semiconductor layer of the transistor is preferably 2 eV or more, more preferably 2.5 eV or more. Use of a metal oxide with a wide band gap can reduce the off-state current of the OS transistor.

[0221] The metal oxide preferably contains at least indium or zinc, and more preferably contains indium and zinc. For example, the metal oxide preferably contains indium, M (M is one or more selected from gallium, aluminum, yttrium, tin, silicon, boron, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt), and zinc.

[0222] Alternatively, the semiconductor layer of the transistor may contain silicon, such as amorphous silicon or crystalline silicon (such as low-temperature polysilicon or single-crystal silicon).

[0223] Examples of metal oxides that can be used in the semiconductor layer include indium oxide, gallium oxide, and zinc oxide. The metal oxide preferably contains two or three elements selected from indium, element M, and zinc. The element 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. In particular, the element M is preferably one or more elements selected from aluminum, gallium, yttrium, and tin.

[0224] In particular, as the metal oxide used in the semiconductor layer, it is preferable to use an oxide containing indium, gallium, and zinc (also referred to as IGZO). Alternatively, it is preferable to use an oxide containing indium, tin, and zinc (also referred to as ITZO (registered trademark)). Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, aluminum, and zinc (also referred to as IAZO). Alternatively, it is preferable to use an oxide containing indium, aluminum, gallium, and zinc (also referred to as IAGZO).

[0225] When the metal oxide used in the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. Examples of atomic ratios of metal elements in such an In-M-Zn oxide include a composition of In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:1:1.2 or thereabouts, In:M:Zn=1:3:2 or thereabouts, In:M:Zn=1:3:4 or thereabouts, In:M:Zn=2:1:3 or thereabouts, In:M:Zn=3:1:2 or thereabouts, In:M:Zn=4:2: Examples of such compositions include a composition of In:M:Zn=4:2:4.1 or a composition of In:M:Zn=5:1:3 or a composition of In:M:Zn=5:1:6 or a composition of In:M:Zn=5:1:7 or a composition of In:M:Zn=5:1:8 or a composition of In:M:Zn=6:1:6 or a composition of In:M:Zn=5:2:5 or a composition of In:M:Zn=5:2:5. Note that a composition of a similar ratio includes a range of ±30% of the desired atomic ratio.

[0226] For example, when describing a composition having an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, this includes a case where, when In is taken as 4, Ga is 1 to 3 and Zn is 2 to 4. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, this includes a case where, when In is taken as 5, Ga is more than 0.1 and 2 or less and Zn is 5 to 7. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, this includes a case where, when In is taken as 1, Ga is more than 0.1 and 2 or less and Zn is more than 0.1 and 2 or less.

[0227] The semiconductor layer may also have two or more metal oxide layers with different compositions. For example, a stacked structure of a first metal oxide layer having an In:M:Zn=1:3:4 (atomic ratio) or a composition similar thereto and a second metal oxide layer having an In:M:Zn=1:1:1 (atomic ratio) or a composition similar thereto provided on the first metal oxide layer is preferably used. Gallium or aluminum is particularly preferably used as the element M.

[0228] Alternatively, for example, a stacked structure of any one selected from indium oxide, indium gallium oxide, and IGZO and any one selected from IAZO, IAGZO, and ITZO (registered trademark) may be used.

[0229] Examples of crystalline oxide semiconductors include c-axis-aligned crystalline (CAAC)-OS, nanocrystalline (nc)-OS, and the like.

[0230] An OS transistor has significantly higher field-effect mobility than a transistor using amorphous silicon. Furthermore, an OS transistor has significantly lower source-drain leakage current in an off state (hereinafter also referred to as off-state current), and can retain charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of an OS transistor can reduce the power consumption of a display panel.

[0231] Furthermore, to increase the emission luminance of a light-emitting device included in a pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting device. To achieve this, it is necessary to increase the source-drain voltage of a driving transistor included in the pixel circuit. Since an OS transistor has a higher source-drain withstand voltage than a Si transistor, a high voltage can be applied between the source and drain of the OS transistor. Therefore, by using an OS transistor as the driving transistor included in a pixel circuit, it is possible to increase the amount of current flowing through the light-emitting device and increase the emission luminance of the light-emitting device.

[0232] Furthermore, when a transistor operates in the saturation region, the change in source-drain current of an OS transistor is smaller than that of a Si transistor in response to a change in gate-source voltage. Therefore, by using an OS transistor as a driving transistor included in a pixel circuit, the current flowing between the source and drain can be precisely controlled by changing the gate-source voltage, thereby controlling the amount of current flowing through the light-emitting device. This allows for a larger gradation in the pixel circuit.

[0233] Furthermore, in terms of the saturation characteristics of the current that flows when a transistor operates in the saturation region, an OS transistor can pass a more stable current (saturation current) than a Si transistor, even when the source-drain voltage gradually increases. Therefore, by using an OS transistor as a driving transistor, a stable current can be passed through a light-emitting device, even when the current-voltage characteristics of an EL device vary. In other words, when an OS transistor operates in the saturation region, the source-drain current of the OS transistor remains almost unchanged even when the source-drain voltage increases, thereby stabilizing the light-emitting luminance of the light-emitting device.

[0234] As described above, by using an OS transistor for a driving transistor included in a pixel circuit, it is possible to achieve "suppression of black floating," "increase in light emission luminance," "multiple gradations," "suppression of variations in light-emitting devices," and the like.

[0235] [Display Panel 200E] A display panel 200E illustrated in FIG. 15 has a stacked structure of a transistor 320A and a transistor 320B each including an oxide semiconductor as a semiconductor in which a channel is formed.

[0236] The transistor 320A, the transistor 320B, and the surrounding configuration can refer to the display panel 200D.

[0237] Although two transistors including an oxide semiconductor are stacked here, the present invention is not limited to this structure, and for example, three or more transistors may be stacked.

[0238] [Display Panel 200F] A display panel 200F shown in FIG. 16 has a stacked structure of a transistor 310 in which a channel is formed in a substrate 301 and a transistor 320 in which a channel is formed and a semiconductor layer containing metal oxide is formed.

[0239] An insulating layer 261 is provided to cover the transistor 310, and a conductive layer 251 is provided over the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided over the insulating layer 262. The conductive layers 251 and 252 each function as wirings. An insulating layer 263 and an insulating layer 332 are provided to cover the conductive layer 252, and the transistor 320 is provided over the insulating layer 332. An insulating layer 265 is provided to cover the transistor 320, and a capacitor 240 is provided over the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0240] The transistor 320 can be used as a transistor that forms a pixel circuit. The transistor 310 can be used as a transistor that forms a pixel circuit or a driver circuit (gate line driver circuit, source line driver circuit) that drives the pixel circuit. The transistors 310 and 320 can be used as transistors that form various circuits such as an arithmetic circuit or a memory circuit.

[0241] With this configuration, not only pixel circuits but also driving circuits etc. can be formed directly below the light-emitting device, making it possible to make the display panel smaller than when driving circuits are provided around the periphery of the display area.

[0242] [Display Panel 200G] The display panel 200G shown in FIG. 17 has a stacked structure of a transistor 310 having a channel formed in a substrate 301, a transistor 320A including a metal oxide in a semiconductor layer in which a channel is formed, and a transistor 320B.

[0243] The transistor 320A can be used as a transistor that constitutes a pixel circuit. The transistor 310 can be used as a transistor that constitutes a pixel circuit or a transistor that constitutes a driver circuit (gate line driver circuit, source line driver circuit) for driving the pixel circuit. The transistor 320B may be used as a transistor that constitutes a pixel circuit or a transistor that constitutes the driver circuit. The transistor 310, the transistor 320A, and the transistor 320B can be used as transistors that constitute various circuits such as an arithmetic circuit or a memory circuit.

[0244] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0245] Embodiment 4 In this embodiment, a light-emitting device (light-emitting element) that can be used for a display panel of one embodiment of the present invention will be described.

[0246] In this specification, etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. Also, in this specification, etc., a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure.

[0247] In this specification, a structure in which at least light-emitting layers are separately fabricated for light-emitting devices with different emission wavelengths may be referred to as an SBS (Side By Side) structure. The SBS structure allows the materials and configuration to be optimized for each light-emitting device, increasing the freedom in material and configuration selection and facilitating improvements in brightness and reliability.

[0248] In this specification and the like, holes or electrons may be referred to as "carriers." Specifically, a hole injection layer or an electron injection layer may be referred to as a "carrier injection layer," a hole transport layer or an electron transport layer may be referred to as a "carrier transport layer," and a hole block layer or an electron block layer may be referred to as a "carrier block layer." Note that the above-mentioned carrier injection layer, carrier transport layer, and carrier block layer may not be clearly distinguishable from each other depending on their cross-sectional shapes or characteristics. Furthermore, one layer may have two or three functions among the carrier injection layer, carrier transport layer, and carrier block layer.

[0249] In this specification and the like, a light-emitting device (also referred to as a light-emitting element) has an EL layer between a pair of electrodes. The EL layer has at least a light-emitting layer. Here, layers (also referred to as functional layers) included in the EL layer include a light-emitting layer, a carrier injection layer (a hole injection layer and an electron injection layer), a carrier transport layer (a hole transport layer and an electron transport layer), and a carrier block layer (a hole block layer and an electron block layer).

[0250] As the light-emitting device, for example, an OLED or a QLED is preferably used. Examples of the light-emitting material contained in the light-emitting device include a fluorescent material (fluorescent material), a phosphorescent material (phosphorescent material), a thermally activated delayed fluorescence (TADF) material), and an inorganic compound (quantum dot material, etc.). Furthermore, an LED such as a micro LED can also be used as the light-emitting device.

[0251] The light emitting device can emit light of infrared, red, green, blue, cyan, magenta, yellow, white, etc. The color purity can be improved by providing the light emitting device with a microcavity structure.

[0252] 18A, the light-emitting device has an EL layer 763 between a pair of electrodes (a lower electrode 761 and an upper electrode 762). The EL layer 763 can be composed of multiple layers, such as a layer 780, a light-emitting layer 771, and a layer 790.

[0253] The light-emitting layer 771 contains at least a light-emitting substance (also referred to as a light-emitting material).

[0254] When the lower electrode 761 is an anode and the upper electrode 762 is a cathode, the layer 780 includes one or more of a layer containing a substance with high hole-injecting properties (hole-injecting layer), a layer containing a substance with high hole-transporting properties (hole-transporting layer), and a layer containing a substance with high electron-blocking properties (electron-blocking layer). The layer 790 also includes one or more of a layer containing a substance with high electron-injecting properties (electron-injecting layer), a layer containing a substance with high electron-transporting properties (electron-transporting layer), and a layer containing a substance with high hole-blocking properties (hole-blocking layer). When the lower electrode 761 is a cathode and the upper electrode 762 is an anode, the layers 780 and 790 have the opposite structures to those described above.

[0255] A structure having the layer 780, the light-emitting layer 771, and the layer 790 provided between a pair of electrodes can function as a single light-emitting unit, and the structure of FIG. 18A is referred to as a single structure in this specification.

[0256] 18B shows a modified example of the EL layer 763 included in the light-emitting device shown in Fig. 18A. Specifically, the light-emitting device shown in Fig. 18B includes a layer 781 on a lower electrode 761, a layer 782 on the layer 781, a light-emitting layer 771 on the layer 782, a layer 791 on the light-emitting layer 771, a layer 792 on the layer 791, and an upper electrode 762 on the layer 792.

[0257] When the lower electrode 761 is an anode and the upper electrode 762 is a cathode, for example, the layer 781 can be a hole injection layer, the layer 782 can be a hole transport layer, the layer 791 can be an electron transport layer, and the layer 792 can be an electron injection layer. When the lower electrode 761 is a cathode and the upper electrode 762 is an anode, the layer 781 can be an electron injection layer, the layer 782 can be an electron transport layer, the layer 791 can be a hole transport layer, and the layer 792 can be a hole injection layer. Such a layer structure allows carriers to be efficiently injected into the light-emitting layer 771, and the efficiency of carrier recombination in the light-emitting layer 771 can be increased.

[0258] 18C and 18D, a variation of the single structure is a configuration in which multiple light-emitting layers (light-emitting layers 771, 772, and 773) are provided between layer 780 and layer 790. While FIGS. 18C and 18D show an example having three light-emitting layers, the number of light-emitting layers in a single-structure light-emitting device may be two, or may be four or more. Furthermore, a light-emitting device with a single structure may have a buffer layer between the two light-emitting layers.

[0259] 18E and 18F, a configuration in which a plurality of light-emitting units (light-emitting unit 763a and light-emitting unit 763b) are connected in series via a charge generation layer 785 (also referred to as an intermediate layer) is referred to as a tandem structure in this specification. The tandem structure may also be referred to as a stack structure. The tandem structure can provide a light-emitting device capable of emitting high-luminance light. Furthermore, the tandem structure can reduce the current required to obtain the same luminance compared to a single structure, thereby improving reliability.

[0260] 18D and 18F show examples in which the display panel has a layer 764 that overlaps with the light-emitting device. Fig. 18D shows an example in which the layer 764 overlaps with the light-emitting device shown in Fig. 18C, and Fig. 18F shows an example in which the layer 764 overlaps with the light-emitting device shown in Fig. 18E.

[0261] The layer 764 can be a color conversion layer, a color filter (coloring layer), or both.

[0262] 18C and 18D , light-emitting layers 771, 772, and 773 may be made of light-emitting materials that emit light of the same color, or even the same light-emitting material. For example, light-emitting layers 771, 772, and 773 may be made of a light-emitting material that emits blue light. In the subpixel that emits blue light, blue light emitted by the light-emitting device can be extracted. Furthermore, in the subpixels that emit red light and the subpixels that emit green light, a color conversion layer can be provided as layer 764 shown in FIG. 18D to convert blue light emitted by the light-emitting device into light with a longer wavelength, thereby extracting red or green light.

[0263] Furthermore, light-emitting materials with different emission colors may be used for the light-emitting layers 771, 772, and 773. When the lights emitted by the light-emitting layers 771, 772, and 773 are complementary in color, white light can be obtained. For example, a light-emitting device with a single structure preferably has a light-emitting layer containing a light-emitting material that emits blue light and a light-emitting layer containing a light-emitting material that emits visible light with a wavelength longer than blue.

[0264] For example, when a light-emitting device with a single structure has three light-emitting layers, it preferably has a light-emitting layer containing a light-emitting material that emits red (R) light, a light-emitting layer containing a light-emitting material that emits green (G) light, and a light-emitting layer containing a light-emitting material that emits blue (B) light. The stacking order of the light-emitting layers can be R, G, B from the anode side, or R, B, G from the anode side, etc. In this case, a buffer layer may be provided between R and G or B.

[0265] For example, when a light-emitting device with a single structure has two light-emitting layers, it is preferable that the light-emitting layer has a light-emitting substance that emits blue (B) light and the light-emitting layer has a light-emitting substance that emits yellow light. This configuration is sometimes called BY single.

[0266] A color filter may be provided as layer 764 shown in Figure 18D. When white light passes through the color filter, light of a desired color can be obtained.

[0267] A light-emitting device that emits white light preferably contains two or more types of light-emitting materials. To obtain white light emission, light-emitting materials can be selected so that the light emitted from each of the two or more light-emitting materials has a complementary color relationship. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary to each other, a light-emitting device that emits white light as a whole can be obtained. The same applies to a light-emitting device having three or more light-emitting layers.

[0268] 18E and 18F, the light-emitting layer 771 and the light-emitting layer 772 may be made of a light-emitting material that emits light of the same color, or even the same light-emitting material.

[0269] For example, in the light-emitting devices included in the subpixels emitting light of each color, light-emitting materials emitting blue light may be used for the light-emitting layers 771 and 772. In the subpixel emitting blue light, the blue light emitted by the light-emitting device can be extracted. In the subpixel emitting red light and the subpixel emitting green light, a color conversion layer is provided as the layer 764 shown in FIG. 18F to convert the blue light emitted by the light-emitting device into light with a longer wavelength, thereby allowing red or green light to be extracted.

[0270] Furthermore, when the light-emitting devices having the configurations shown in FIG. 18E or 18F are used for the subpixels emitting light of each color, different light-emitting materials may be used for each subpixel. Specifically, in a light-emitting device included in a subpixel emitting red light, light-emitting materials that emit red light may be used for the light-emitting layers 771 and 772, respectively. Similarly, in a light-emitting device included in a subpixel emitting green light, light-emitting materials that emit green light may be used for the light-emitting layers 771 and 772, respectively. In a light-emitting device included in a subpixel emitting blue light, light-emitting materials that emit blue light may be used for the light-emitting layers 771 and 772, respectively. A display panel having such a configuration can be said to employ a tandem-structure light-emitting device and also have an SBS structure. Therefore, it can have the advantages of both the tandem structure and the SBS structure. This allows for a highly reliable light-emitting device capable of emitting high-brightness light.

[0271] 18E and 18F, light-emitting layers 771 and 772 may be made of light-emitting materials that emit light of different colors. When the light emitted by light-emitting layer 771 and the light emitted by light-emitting layer 772 are complementary colors, white light can be obtained. A color filter may be provided as layer 764 shown in FIG. 18F. When white light passes through the color filter, light of a desired color can be obtained.

[0272] 18E and 18F show an example in which the light-emitting unit 763a has one light-emitting layer 771 and the light-emitting unit 763b has one light-emitting layer 772, but this is not limiting. Each of the light-emitting unit 763a and the light-emitting unit 763b may have two or more light-emitting layers.

[0273] 18E and 18F show examples of light emitting devices having two light emitting units, but the present invention is not limited to this and the light emitting device may have three or more light emitting units.

[0274] Specifically, the light-emitting device configurations shown in FIGS. 19A to 19C can be given.

[0275] 19A shows a configuration having three light-emitting units. Note that a configuration having two light-emitting units may be called a two-stage tandem structure, and a configuration having three light-emitting units may be called a three-stage tandem structure.

[0276] 19A , a plurality of light-emitting units (light-emitting unit 763a, light-emitting unit 763b, and light-emitting unit 763c) are connected in series via charge generation layer 785. Light-emitting unit 763a includes layer 780a, light-emitting layer 771, and layer 790a, light-emitting unit 763b includes layer 780b, light-emitting layer 772, and layer 790b, and light-emitting unit 763c includes layer 780c, light-emitting layer 773, and layer 790c.

[0277] 19A , it is preferable that the light-emitting layers 771, 772, and 773 each contain a light-emitting material that emits light of the same color. Specifically, the light-emitting layers 771, 772, and 773 may each contain a red (R) light-emitting material (a so-called R\R\R three-stage tandem structure), the light-emitting layers 771, 772, and 773 may each contain a green (G) light-emitting material (a so-called G\G\G three-stage tandem structure), or the light-emitting layers 771, 772, and 773 may each contain a blue (B) light-emitting material (a so-called B\B\B three-stage tandem structure).

[0278] Note that the light-emitting materials that emit light of the same color are not limited to the above configuration. For example, as shown in FIG. 19B , a tandem light-emitting device may be used in which light-emitting units having multiple light-emitting materials are stacked. FIG. 19B shows a configuration in which multiple light-emitting units (light-emitting unit 763a and light-emitting unit 763b) are connected in series via charge generation layer 785. Furthermore, light-emitting unit 763a includes layer 780a, light-emitting layer 771a, light-emitting layer 771b, light-emitting layer 771c, and layer 790a. Light-emitting unit 763b includes layer 780b, light-emitting layer 772a, light-emitting layer 772b, light-emitting layer 772c, and layer 790b.

[0279] In the structure shown in FIG. 19B , light-emitting layers 771a, 771b, and 771c are configured to emit white light (W) by selecting light-emitting materials with complementary colors. Light-emitting layers 772a, 772b, and 772c are configured to emit white light (W) by selecting light-emitting materials with complementary colors. That is, the structure shown in FIG. 19C has a W\W two-tier tandem structure. Note that there are no particular limitations on the stacking order of the light-emitting materials with complementary colors for light-emitting layers 771a, 771b, and 771c. The implementer can select the optimal stacking order as appropriate. Although not shown, a W\W\W three-tier tandem structure or a four-tier or more tandem structure may also be used.

[0280] In addition, when a light-emitting device having a tandem structure is used, there are a B\Y two-stage tandem structure having a light-emitting unit that emits yellow (Y) light and a light-emitting unit that emits blue (B) light, a R·G\B two-stage tandem structure having a light-emitting unit that emits red (R) and green (G) light and a light-emitting unit that emits blue (B) light, a light-emitting unit that emits yellow (Y) light and a light-emitting unit that emits blue (B) light, and a light-emitting unit that emits blue (B) light. Examples of such a tandem structure include a B\Y\B three-stage tandem structure having, in this order, a light-emitting unit that emits blue (B) light, a light-emitting unit that emits yellow-green (YG) light, and a light-emitting unit that emits blue (B) light, and a B\G\B three-stage tandem structure having, in this order, a light-emitting unit that emits blue (B) light, a light-emitting unit that emits green (G) light, and a light-emitting unit that emits blue (B) light.

[0281] Furthermore, as shown in FIG. 19C, a light-emitting unit having one light-emitting substance and a light-emitting unit having a plurality of light-emitting substances may be combined.

[0282] 19C , a plurality of light-emitting units (light-emitting unit 763a, light-emitting unit 763b, and light-emitting unit 763c) are connected in series via charge generation layer 785. Light-emitting unit 763a includes layer 780a, light-emitting layer 771, and layer 790a, light-emitting unit 763b includes layer 780b, light-emitting layer 772a, light-emitting layer 772b, light-emitting layer 772c, and layer 790b, and light-emitting unit 763c includes layer 780c, light-emitting layer 773, and layer 790c.

[0283] For example, in the configuration shown in Figure 19C, a three-stage tandem structure of B\R·G·YG\B can be applied, in which light-emitting unit 763a is a light-emitting unit that emits blue (B) light, light-emitting unit 763b is a light-emitting unit that emits red (R), green (G), and yellow-green (YG) light, and light-emitting unit 763c is a light-emitting unit that emits blue (B) light.

[0284] For example, the number of layers of the light-emitting units and the order of the colors can be, from the anode side, a two-layer structure of B and Y, a two-layer structure of B and light-emitting unit X, a three-layer structure of B, Y, and B, and the number of layers of the light-emitting layers in light-emitting unit X and the order of the colors can be, from the anode side, a two-layer structure of R 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.

[0285] 18C and 18D, the layer 780 and the layer 790 may each independently have a laminated structure made up of two or more layers, as shown in FIG. 18B.

[0286] 18E and 18F, light-emitting unit 763a includes layer 780a, light-emitting layer 771, and layer 790a, and light-emitting unit 763b includes layer 780b, light-emitting layer 772, and layer 790b.

[0287] When the lower electrode 761 is an anode and the upper electrode 762 is a cathode, the layers 780a and 780b each have one or more of a hole injection layer, a hole transport layer, and an electron blocking layer. The layers 790a and 790b each have one or more of an electron injection layer, an electron transport layer, and a hole blocking layer. When the lower electrode 761 is a cathode and the upper electrode 762 is an anode, the layers 780a and 790a have the opposite structures to those described above, and the layers 780b and 790b also have the opposite structures to those described above.

[0288] When the lower electrode 761 is an anode and the upper electrode 762 is a cathode, for example, the layer 780a may have a hole injection layer, a hole transport layer on the hole injection layer, and an electron blocking layer on the hole transport layer. The layer 790a may have an electron transport layer and a hole blocking layer between the light-emitting layer 771 and the electron transport layer. The layer 780b may have a hole transport layer and an electron blocking layer on the hole transport layer. The layer 790b may have an electron transport layer, an electron injection layer on the electron transport layer, and a hole blocking layer between the light-emitting layer 772 and the electron transport layer. When the lower electrode 761 is a cathode and the upper electrode 762 is an anode, for example, the layer 780a may have an electron injection layer, an electron transport layer on the electron injection layer, and an electron blocking layer on the electron transport layer. Layer 790a has a hole transport layer and may further have an electron blocking layer between light-emitting layer 771 and the hole transport layer. Layer 780b has an electron transport layer and may further have a hole blocking layer on the electron transport layer. Layer 790b has a hole transport layer and a hole injection layer on the hole transport layer and may further have an electron blocking layer between light-emitting layer 772 and the hole transport layer.

[0289] When a light-emitting device having a tandem structure is fabricated, two light-emitting units are stacked via a charge generation layer 785. The charge generation layer 785 has at least a charge generation region. The charge generation layer 785 has a function of injecting electrons into one of the two light-emitting units and injecting holes into the other when a voltage is applied between a pair of electrodes.

[0290] Next, materials that can be used in light-emitting devices will be described.

[0291] Of the lower electrode 761 and the upper electrode 762, a conductive film that transmits visible light is used for the electrode from which light is extracted. It is preferable to use a conductive film that reflects visible light for the electrode from which light is not extracted. When the display panel has a light-emitting device that emits infrared light, it is preferable to use a conductive film that transmits visible light and infrared light for the electrode from which light is extracted, and a conductive film that reflects visible light and infrared light for the electrode from which light is not extracted.

[0292] A conductive film that transmits visible light may also be used for the electrode on the side from which light is not extracted. In this case, the electrode is preferably disposed between the reflective layer and the EL layer 763. That is, light emitted from the EL layer 763 may be reflected by the reflective layer and extracted from the display panel.

[0293] Materials for forming the pair of electrodes of a light-emitting device can include metals, alloys, electrically conductive compounds, and mixtures thereof. Specific examples of such materials include metals such as aluminum, titanium, chromium, manganese, iron, cobalt, nickel, copper, gallium, zinc, indium, tin, molybdenum, tantalum, tungsten, palladium, gold, platinum, silver, yttrium, and neodymium, as well as alloys containing these metals in combination. Examples of such materials include indium tin oxide (In-Sn oxide, also referred to as ITO), In-Si-Sn oxide (also referred to as ITSO), indium zinc oxide (In-Zn oxide), and In-W-Zn oxide. Examples of such materials include aluminum alloys, such as an aluminum-nickel-lanthanum alloy (Al-Ni-La), and an alloy of silver, palladium, and copper (Ag-Pd-Cu, also referred to as APC). Other examples of the material include elements belonging to Group 1 or 2 of the periodic table (e.g., lithium, cesium, calcium, and strontium) that are not listed above as examples, rare earth metals such as europium and ytterbium, alloys containing appropriate combinations of these, and graphene.

[0294] The light-emitting device preferably has a micro-optical resonator (microcavity) structure. Therefore, one of a pair of electrodes of the light-emitting device is preferably an electrode that is transparent and reflective to visible light (semi-transmissive / semi-reflective electrode), and the other is preferably an electrode that is reflective to visible light (reflective electrode). By having the light-emitting device have a microcavity structure, light emitted from the light-emitting layer can be resonated between the two electrodes, thereby intensifying the light emitted from the light-emitting device.

[0295] The semi-transmitting / semi-reflective electrode can have a stacked structure of a conductive layer that can be used as a reflective electrode and a conductive layer that can be used as an electrode that is transparent to visible light (also referred to as a transparent electrode).

[0296] The light transmittance of the transparent electrode is 40% or more. For example, it is preferable to use an electrode having a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more for the transparent electrode of a light-emitting device. The visible light reflectance of the semi-transmissive / semi-reflective electrode is 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes is 1×10 −２ Preferably, it is Ωcm or less.

[0297] The light-emitting device has at least a light-emitting layer. The light-emitting device may further include a layer other than the light-emitting layer, which layer contains a substance with high hole-injection properties, a substance with high hole-transport properties, a hole-blocking material, a substance with high electron-transport properties, an electron-blocking material, a substance with high electron-injection properties, or a bipolar substance (a substance with high electron-transport properties and high hole-transport properties). For example, the light-emitting device may have, in addition to the light-emitting layer, one or more layers selected from a hole-injection layer, a hole-transport layer, a hole-blocking layer, a charge-generating layer, an electron-blocking layer, an electron-transport layer, and an electron-injection layer.

[0298] The light-emitting device can be made of either a low-molecular-weight compound or a high-molecular-weight compound, and may contain an inorganic compound. The layers constituting the light-emitting device can be formed by a method such as vapor deposition (including vacuum vapor deposition), transfer, printing, inkjet printing, or coating.

[0299] The light-emitting layer contains one or more light-emitting materials. As the light-emitting material, a material that emits light of blue, purple, blue-purple, green, yellow-green, yellow, orange, red, or the like is appropriately used. Furthermore, a material that emits near-infrared light can also be used as the light-emitting material.

[0300] The light-emitting material may include a fluorescent material, a phosphorescent material, a TADF material, and a quantum dot material.

[0301] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0302] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, a pyrazine skeleton, or a pyridine skeleton; organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand; platinum complexes; and rare earth metal complexes.

[0303] The light-emitting layer may contain one or more organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). As the one or more organic compounds, one or both of a substance with high hole transport properties (hole transport material) and a substance with high electron transport properties (electron transport material) can be used. As the hole-transporting material, a material with high hole transport properties that can be used in the hole-transporting layer, which will be described later, can be used. As the electron-transporting material, a material with high electron transport properties that can be used in the electron-transporting layer, which will be described later, can be used. Furthermore, as the one or more organic compounds, a bipolar material or a TADF material may be used.

[0304] The light-emitting layer preferably includes, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material that are a combination that easily forms an exciplex. This configuration allows for efficient emission using Exciplex-Triple Energy Transfer (ExTET), which is energy transfer from the exciplex to the light-emitting material (phosphorescent material). By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material, energy transfer becomes smooth, allowing for efficient emission. This configuration simultaneously enables high efficiency, low-voltage operation, and long life of the light-emitting device.

[0305] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a material with high hole injection properties, such as an aromatic amine compound and a composite material containing a hole transport material and an acceptor material (electron acceptor material).

[0306] As the hole transporting material, a material having high hole transporting properties that can be used for the hole transport layer, which will be described later, can be used.

[0307] Examples of acceptable materials include oxides of metals belonging to Groups 4 to 8 of the periodic table. Specific examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is particularly preferred because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle. Also, organic acceptable materials containing fluorine can be used. Other acceptable materials include quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives.

[0308] For example, as a material with high hole injection properties, a material containing a hole transporting material and an oxide of a metal belonging to Groups 4 to 8 of the periodic table (typically, molybdenum oxide) may be used.

[0309] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light emitting layer. The hole transport layer is a layer that contains a hole transport material. The hole transport material is a material having a concentration of 1×10 −６ cm ２ A substance having a hole mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, a material having a high hole transporting property, such as a π-electron-rich heteroaromatic compound (e.g., a carbazole derivative, a thiophene derivative, a furan derivative, etc.) or an aromatic amine (a compound having an aromatic amine skeleton), is preferred.

[0310] The electron blocking layer is provided in contact with the light-emitting layer. The electron blocking layer is a layer containing a material that has hole transport properties and can block electrons. The electron blocking layer can be made of a material that has electron blocking properties among the hole transport materials described above.

[0311] The electron blocking layer has hole transport properties and can therefore also be called a hole transport layer. Furthermore, a layer of the hole transport layer that has electron blocking properties can also be called an electron blocking layer.

[0312] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light emitting layer. The electron transport layer is a layer that contains an electron transporting material. The electron transporting material is a material having a molecular weight of 1×10 −６ cm ２ A substance having an electron mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher electron transporting property than holes. Examples of electron-transporting materials that can be used include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, and metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds.

[0313] The hole-blocking layer is provided in contact with the light-emitting layer. The hole-blocking layer is a layer containing a material that has electron transport properties and can block holes. The hole-blocking layer can be made of a material that has hole-blocking properties and is selected from the above electron-transporting materials.

[0314] The hole blocking layer has electron transport properties and can therefore also be called an electron transport layer. Furthermore, a layer of the electron transport layer that has hole blocking properties can also be called a hole blocking layer.

[0315] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a material with high electron injection properties. Examples of the material with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the material with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0316] Furthermore, it is preferable that the LUMO level of the material having high electron injection properties has a small difference from the work function value of the material used for the cathode (specifically, 0.5 eV or less).

[0317] The electron injection layer may contain, for example, lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ｘ , x is an arbitrary number), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatolithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviation: LiPPP), lithium oxide (LiO ｘ ), alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. The electron injection layer may have a stacked structure of two or more layers. For example, the stacked structure may have a structure in which lithium fluoride is used as the first layer and ytterbium is provided as the second layer.

[0318] The electron injection layer may contain an electron transporting material. For example, a compound having an unshared electron pair and an electron-deficient heteroaromatic ring can be used as the electron transporting material. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), and a triazine ring can be used.

[0319] The lowest unoccupied molecular orbital (LUMO) level of an organic compound having an unshared electron pair is preferably −3.6 eV or more and −2.3 eV or less. Generally, the highest occupied molecular orbital (HOMO) level and the LUMO level of an organic compound can be estimated by CV (cyclic voltammetry), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, or the like.

[0320] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviation: BPhen), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2,2′-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), diquinoxalino[2,3-a:2′,3′-c]phenazine (abbreviation: HATNA), 2,4,6-tris[3′-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), etc. can be used as the organic compound having an unshared electron pair. Note that NBPhen has a higher glass transition point (Tg) and is superior in heat resistance compared to BPhen.

[0321] As described above, the charge generation layer has at least a charge generation region. The charge generation region preferably contains an acceptor material, for example, a hole transport material and an acceptor material applicable to the hole injection layer.

[0322] The charge generation layer preferably includes a layer containing a material with high electron injection properties. This layer may also be called an electron injection buffer layer. The electron injection buffer layer is preferably provided between the charge generation region and the electron transport layer. By providing the electron injection buffer layer, the injection barrier between the charge generation region and the electron transport layer can be alleviated, so that electrons generated in the charge generation region can be easily injected into the electron transport layer.

[0323] The electron injection buffer layer preferably contains an alkali metal or an alkaline earth metal, and may contain, for example, an alkali metal compound or an alkaline earth metal compound. Specifically, the electron injection buffer layer preferably contains an inorganic compound containing an alkali metal and oxygen, or an inorganic compound containing an alkaline earth metal and oxygen, and may contain an inorganic compound containing lithium and oxygen (lithium oxide (Li ２ In addition, the electron injection buffer layer can be suitably made of the materials applicable to the electron injection layer described above.

[0324] The charge generation layer preferably has a layer containing a material with high electron transport properties. This layer can also be called an electron relay layer. The electron relay layer is preferably provided between the charge generation region and the electron injection buffer layer. When the charge generation layer does not have an electron injection buffer layer, the electron relay layer is preferably provided between the charge generation region and the electron transport layer. The electron relay layer has the function of preventing interaction between the charge generation region and the electron injection buffer layer (or the electron transport layer) and smoothly transferring electrons.

[0325] For the electron relay layer, it is preferable to use a phthalocyanine-based material such as copper (II) phthalocyanine (abbreviated as CuPc) or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0326] It should be noted that the charge generation region, electron injection buffer layer, and electron relay layer may not be clearly distinguishable from one another depending on their cross-sectional shapes or characteristics.

[0327] The charge generation layer may contain a donor material instead of an acceptor material. For example, the charge generation layer may contain a layer containing an electron transport material and a donor material that can be used for the electron injection layer.

[0328] When light-emitting units are stacked, an increase in driving voltage can be suppressed by providing a charge generating layer between two light-emitting units.

[0329] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be appropriately combined with other configuration examples or drawings.

[0330] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0331] 10: eye, 30: display device, 31: display panel, 32: polarizer, 35: display unit, 40: optical device, 41: reflective polarizer, 42a: lens, 42b: lens, 42: lens, 43: optical rotator, 44: reflective polarizer, 45: lens, 51: retardation plate, 52: half mirror, 53: retardation plate, 54: reflective polarizer, 60: housing, 61: band, 70: pixel, 71: subpixel, 74: pixel array, 75: circuit, 76: circuit, 81: layer, 82: layer, 83: layer, 100a: display panel, 100b: display panel, 100W: light-emitting element, 100: display panel, 101: substrate, 110a: light-emitting element, 110B: light-emitting element, 110b: light-emitting element, 110c: light-emitting element, 110G: light-emitting element, 110R: light-emitting element, 110: light-emitting element, 111B: pixel electrode, 111C: connection electrode, 111G: pixel electrode, 111R: pixel electrode, 111: pixel electrode, 112B: organic layer, 112G: organic layer, 112R: organic layer, 112W: organic layer, 112: organic layer, 113: common electrode, 114: common layer, 115B: conductive layer, 115G: conductive layer, 115R: conductive layer, 115: optical adjustment layer, 116B: colored layer, 116G: colored layer, 116R: colored layer, 121: retention protective layer, 122: insulating layer, 123: insulating layer, 124a: pixel, 124b: pixel, 125: insulating layer, 126: resin layer, 128: layer, 140: connecting portion, 150: pixel, 170: substrate, 171: adhesive layer, 200A: display panel, 200B: display panel, 200C: display panel, 200D: display panel, 200E: display panel, 200F: display panel, 200G: display panel, 240: capacitor, 241: conductive layer, 243: insulating layer, 245: conductive layer, 251: conductive layer, 252: conductive layer, 254: insulating layer, 255a: insulating layer, 255b: insulating layer, 255c: insulating layer, 25 6: plug, 261: insulating layer, 262: insulating layer, 263: insulating layer, 264: insulating layer, 265: insulating layer, 271: plug, 274a: conductive layer, 274b: conductive layer, 274: plug, 280: display module, 281: display section, 282: circuit section, 283a: pixel circuit, 283: pixel circuit section, 284a: pixel, 284: pixel section, 285: terminal section, 286: wiring section, 290: FPC, 291: substrate, 292: substrate, 301A: substrate, 301B: substrate, 301: substrate, 310A: transistor, 310B: transistor, 310: transistor, 311: conductive layer,312: low resistance region, 313: insulating layer, 314: insulating layer, 315: element isolation layer, 320A: transistor, 320B: transistor, 320: transistor, 321: semiconductor layer, 323: insulating layer, 324: conductive layer, 325: conductive layer, 326: insulating layer, 327: conductive layer, 328: insulating layer, 329: insulating layer, 331: substrate, 332: insulating layer, 335: insulating layer, 336: insulating layer, 341: conductive layer, 342: conductive layer, 343: plug, 344: insulating layer, 345: insulating layer, 346: insulating layer, 347: bump, 348: adhesive layer, 7 61: lower electrode, 762: upper electrode, 763a: light-emitting unit, 763b: light-emitting unit, 763c: light-emitting unit, 763: EL layer, 764: layer, 771a: light-emitting layer, 771b: light-emitting layer, 771c: light-emitting layer, 771: light-emitting layer, 772a: light-emitting layer, 772b: light-emitting layer, 772c: light-emitting layer, 772: light-emitting layer, 773: light-emitting layer, 780a: layer, 780b: layer, 780c: layer, 780: layer, 781: layer, 782: layer, 785: charge generation layer, 790a: layer, 790b: layer, 790c: layer, 790: layer, 791: layer, 792: layer,

Claims

1. A light source comprising a first lens, a polarizer, a first reflective polarizer, a second lens, a rotator, a second reflective polarizer, and a third lens; the first lens, the polarizing plate, the first reflective polarizing plate, the second lens, the second reflective polarizing plate, the optical rotator, and the third lens are arranged in this order so as to have overlapping regions with each other; The optical device is such that the second lens and the polarization rotator are spaced apart from each other.

2. In claim 1, a first surface of the first reflective polarizer bonded to a first surface of the polarizer; a second surface of the first reflective polarizer bonded to a first surface of the second lens; An optical device, wherein the second surface of the polarizing plate is bonded to the first surface of the first lens.

3. In claim 1 or 2, a first surface of the optical rotator is bonded to a first surface of the second reflective polarizer; An optical device, wherein a second surface of the second reflective polarizing plate opposite to the first surface is bonded to the first surface of the third lens.

4. In claim 1 or 2, the first reflective polarizer transmits a first linearly polarized light and reflects a second linearly polarized light that is orthogonal to the first linearly polarized light; The second reflective polarizing plate reflects third linearly polarized light, the polarization plane of which is rotated 45° from the first linearly polarized light, and transmits fourth linearly polarized light that is orthogonal to the third linearly polarized light.

5. In claim 1 or 2, The optical device has an optical rotation angle of 45°.

6. In claim 1 or 2, The optical device, wherein the first lens and the second lens are convex lenses.

7. a display panel, a first lens, a polarizing plate, a first reflective polarizing plate, a second lens, an optical rotator, a second reflective polarizing plate, and a third lens are disposed in a housing; the display panel, the first lens, the polarizing plate, the first reflective polarizing plate, the second lens, the second reflective polarizing plate, the optical rotator, and the third lens are arranged in this order so as to have overlapping regions with each other; The electronic device is configured such that the second lens and the polarization rotator are spaced apart from each other.

8. In claim 7, The electronic device, wherein the display surface of the display panel is provided facing a second surface of the first lens opposite to the first surface.

9. In claim 7 or 8, a first surface of the first reflective polarizer bonded to a first surface of the polarizer; a second surface of the first reflective polarizer bonded to a first surface of the second lens; The electronic device, wherein the second surface of the polarizing plate is bonded to the first surface of the first lens.

10. In claim 7 or 8, a first surface of the optical rotator is bonded to a first surface of the second reflective polarizer; a second surface of the second reflective polarizing plate opposite to the first surface thereof is bonded to the first surface of the third lens;

11. In claim 7 or 8, the polarizing plate transmits a first linearly polarized light; the first reflective polarizer transmits the first linearly polarized light and reflects a second linearly polarized light that is orthogonal to the first linearly polarized light; The electronic device wherein the second reflective polarizer reflects third linearly polarized light, the polarization plane of which is rotated 45° from the first linearly polarized light, and transmits fourth linearly polarized light that is orthogonal to the third linearly polarized light.

12. In claim 7 or 8, The electronic device has an optical rotator with an optical rotation angle of 45°.

13. In claim 7 or 8, The electronic device, wherein the first lens and the second lens are convex lenses.