Optical instruments and electronic equipment

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

Technical Field

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

[0002] Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification or the like relates to an object, a method, or a manufacturing method. Or, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, as the technical field of one aspect of the present invention disclosed in this specification, semiconductor devices, display devices, liquid crystal display devices, light emitting devices, lighting devices, power storage devices, storage devices, imaging devices, their operating methods, or their manufacturing methods can be cited as an example.

[0003] Note that in this specification or the like, the semiconductor device refers to all devices that can function by utilizing semiconductor characteristics. Transistors and semiconductor circuits are one aspect of semiconductor devices. In addition, storage devices, display devices, imaging devices, and electronic devices may have semiconductor devices.

Background Art

[0004] As electronic devices for virtual reality (VR) or augmented reality (AR), etc., goggle-type devices and glasses-type devices have been developed.

[0005] In addition, typical display devices applicable to display panels include display devices provided with liquid crystal elements, display devices provided with organic EL (Electro Luminescence) elements or light emitting diodes (LEDs), etc.

[0006] Display devices equipped with organic EL elements do not require a backlight, which is necessary for liquid crystal displays, thus enabling the realization of thin, lightweight, high-contrast, and low-power display devices. For example, an example of a display device using organic EL elements is described in Patent Document 1. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2002-324673 [Overview of the project] [Problems that the invention aims to solve]

[0008] Electronic devices such as goggles and eyeglasses are a type of wearable device, and it is desirable that they be small and thin to improve portability and wearability. Therefore, such electronic devices use thin optical instruments designed to have a short focal length.

[0009] However, the optical device in question uses a half-mirror with low light utilization efficiency, requiring the brightness of the display device to be increased. Increasing the brightness of the display device leads to increased power consumption and a decrease in the reliability of the display device. Therefore, there is a demand for thin optical devices with high light utilization efficiency.

[0010] Therefore, one aspect of the present invention aims to provide a thin optical device with high light utilization efficiency. Alternatively, one aspect aims to provide a small electronic device having said optical device. Alternatively, one aspect aims to provide an electronic device with low power consumption. Alternatively, one aspect aims to provide a novel electronic device.

[0011] Furthermore, the description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not need to solve all of these problems. Other problems will naturally become apparent from the description in the specification, drawings, and claims, and it is possible to extract other problems from the description in the specification, drawings, and claims. [Means for solving the problem]

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

[0013] One aspect of the present invention is an optical instrument comprising a first reflective polarizer, a first lens, a photon, a second reflective polarizer, and a second lens, wherein the first reflective polarizer, the first lens, the photon, the second reflective polarizer, and the second lens are arranged in such order that each has overlapping regions, and the first lens and the photon are separated.

[0014] The first surface of the first reflective polarizing plate can be bonded to the first surface of the first lens.

[0015] The first surface of the photon can be bonded to the first surface of the second reflective polarizer. Furthermore, the second surface of the second reflective polarizer, opposite to the first surface, can be bonded to the first surface of the second lens.

[0016] The first reflective polarizer transmits first linearly polarized light and reflects second linearly polarized light perpendicular to the first linearly polarized light, while the second reflective polarizer reflects third linearly polarized light in which the polarization plane of the first linearly polarized light is rotated by 45° and transmits fourth linearly polarized light perpendicular to the third linearly polarized light.

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

[0018] The first and second lenses can be convex lenses.

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

[0020] Another aspect of the present invention has a display panel, a polarizing plate, a first reflective polarizing plate, a first lens, a rotator, a second reflective polarizing plate, and a second lens in a housing, and the display panel, the polarizing plate, the first reflective polarizing plate, the first lens, the rotator, the second reflective polarizing plate, and the second lens are arranged in this order so that each has an overlapping region with each other, the polarizing plate and the first reflective polarizing plate are arranged separately, and the first lens and the rotator are arranged separately.

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

[0022] The first surface of the first reflective polarizing plate can be bonded to the first surface of the first lens.

[0023] The first surface of the rotator is bonded to the first surface of the second reflective polarizing plate, and the second surface on the opposite side of the first surface of the second reflective polarizing plate can be bonded to the first surface of the second lens.

[0024] The polarizing plate can transmit the first linearly polarized light, the first reflective polarizing plate can transmit the first linearly polarized light and reflect the second linearly polarized light orthogonal to the first linearly polarized light, the second reflective polarizing plate can reflect the third linearly polarized light whose polarization plane of the first linearly polarized light is rotated by 45°, and can transmit the fourth linearly polarized light orthogonal to the third linearly polarized light.

[0025] The rotator can have a rotation angle of 45°.

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

Advantages of the Invention

[0027] According to one aspect of the present invention, it is possible to provide a thin optical device with high light utilization efficiency, or a small electronic device having said optical device, or a low-power electronic device, or a novel electronic device.

[0028] Furthermore, the description of these effects does not preclude the existence of other effects. One aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description, drawings, and claims. [Brief explanation of the drawing]

[0029] Figure 1 illustrates a display device and an optical device. Figures 2A and 2B illustrate optical instruments. Figures 3A and 3B illustrate optical instruments. Figures 4A through 4G illustrate optical instruments. Figures 5A to 5C illustrate electronic devices. Figures 6A and 6B illustrate the eyeglass-type device. Figures 7A to 7C illustrate examples of display panel configurations. Figures 8A and 8B illustrate examples of display panel configurations. Figures 9A to 9F illustrate examples of pixel configurations. Figures 10A and 10B illustrate an example of the display panel configuration. Figure 11 illustrates an example of the display panel configuration. Figure 12 illustrates an example of the display panel configuration. Figure 13 illustrates an example of the display panel configuration. Figure 14 illustrates an example of the display panel configuration. Figure 15 illustrates an example of the display panel configuration. Figure 16 illustrates an example of the display panel configuration. Figure 17 illustrates an example of the display panel configuration. Figures 18A to 18F illustrate examples of the configuration of a light-emitting device. Figures 19A to 19C illustrate examples of the configuration of a light-emitting device. [Modes for carrying out the invention]

[0030] Embodiments will be described in detail with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the invention. Therefore, the present invention is not to be interpreted as being limited to the descriptions of the embodiments shown below. In the configuration of the invention described below, the same reference numerals are used in common between different drawings for the same parts or parts having similar functions, and repeated descriptions may be omitted. In addition, hatching of the same elements constituting the figures may be omitted or changed as appropriate between different drawings.

[0031] Furthermore, even if an element is shown as a single element in a circuit diagram, it may be composed of multiple elements as long as there is no functional disadvantage. For example, multiple transistors that act as switches may be connected in series or parallel. Also, a capacitor may be divided and placed in multiple locations.

[0032] Furthermore, a single conductor may have multiple functions, such as wiring, electrodes, and terminals, and in this specification, multiple designations may be used for the same element. Also, even if elements are shown as directly connected in a circuit diagram, they may actually be connected via one or more conductors, and in this specification, such configurations are included in the category of direct connection.

[0033] (Embodiment 1) This embodiment describes an optical instrument and an electronic device according to one aspect of the present invention.

[0034] One aspect of the present invention is a thin optical device having a reflective polarizer, a lens, and a photorotator. This optical device is made thin and has a short overall length by utilizing the rotation of the polarization plane of linearly polarized light by the photorotator and the light transmission and reflection characteristics of the reflective polarizer. Furthermore, since the optical device of this aspect does not use a half mirror, it has the characteristic of high light utilization efficiency.

[0035] Electronic devices such as goggles or eyeglasses have a configuration that combines a display device and an optical device to widen the field of view. By using an optical device according to one aspect of the present invention in such an electronic device, it is possible to create a compact, thin, low-power, and highly reliable electronic device.

[0036] Furthermore, one embodiment of the present invention is an optical instrument having a configuration in which multiple optical components are combined. When this configuration is housed in a casing, it is simply called a lens. Alternatively, due to its thin shape, it may be called a pancake lens.

[0037] Figure 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. The display device 30 and the optical device 40 are arranged at a distance from each other such that they have overlapping areas.

[0038] The user can view the image displayed on the display device 30 by bringing their eyes 10 close to the optical device 40. Because the user views the image with a widened field of view provided by the optical device 40, they can experience a sense of immersion and presence.

[0039] The display device 30 has a configuration in which the display panel 31 and the polarizing plate 32 are arranged so that they overlap each other. For example, as shown in Figure 1, the polarizing plate 32 can be attached to the display surface of the display panel 31.

[0040] The polarizing plate 32 does not necessarily have to be an element of the display device 30; it may be provided between the display device 30 (display panel 31) and the optical device 40. Alternatively, it may be an element of the optical device 40, positioned on the side of the optical device 40 where light is incident.

[0041] The optical instrument 40 has a region where the reflective polarizer 41, lens 42, photorotator 43, reflective polarizer 44, and lens 45 overlap each other. 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] For example, as shown in Figure 1, the first surface of the reflective polarizer 41 can be bonded to the first surface of the lens 42. Alternatively, the first surface of the reflective polarizer 44 can be bonded to the first surface of the photon 43, and the first surface of the lens 45 can be bonded to the second surface of the reflective polarizer 44. It is also possible for these elements to be arranged independently without being bonded together.

[0043] Furthermore, in order to secure the necessary optical path length, it is preferable to arrange the lens 42 and the reflective polarizer 44 at a distance from each other. Therefore, when the photon 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 photon 43 at a distance from each other.

[0044] Furthermore, for bonding one element to the other as described above, an optical adhesive can be used that has high transmittance with respect to the wavelength of light used (for example, the wavelength range of visible light) and does not absorb or exhibit optical activity of specific polarizations. Alternatively, instead of bonding, the other element may be formed by contacting it onto one element using a method such as coating.

[0045] Figure 2A is a diagram illustrating a part of the optical path of an optical device according to one embodiment of the present invention, with the optical path shown by a dashed line. For clarity, some elements that are shown touching in Figure 1 are shown separated in Figure 2A. Note that the effects of one embodiment of the present invention can also be obtained by arranging the elements as shown in Figure 2A.

[0046] Some of the light emitted from the display panel 31 passes through the polarizer 32, the reflective polarizer 41, the lens 42, and the photon 43, and is reflected by the reflective polarizer 44. The light reflected by the reflective polarizer 44 passes through the photon 43 and the lens 42, and is reflected again by the reflective polarizer 41. The light reflected by the reflective polarizer 41 passes through the lens 42, the photon 43, the reflective polarizer 44, and the lens 45, and is incident on the eye 10.

[0047] By repeatedly reflecting light in this manner, the optical path length can be secured, allowing for the construction of an optical system with a short focal length.

[0048] As the display panel 31, a liquid crystal panel having liquid crystal elements, an organic EL panel having organic EL elements, or an LED panel having microLEDs can be used. In particular, it is preferable to use an organic EL panel, which is self-emissive and can easily form a high-definition display area.

[0049] The polarizing plate 32 can extract a single linearly polarized light from light vibrating in all 360° directions. In this embodiment, the transmission axis of the polarizing plate 32 is described as 0°, but 0° is not an absolute value, but rather 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° linear polarization means linear polarization 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 perpendicular 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 lenses 42 and 45. Figure 2A shows an example in which a biconvex lens is used for lens 42 and a plano-convex lens is used for lens 45, but this is not the only option. For example, lens 42 may be composed of multiple plano-convex lenses. Alternatively, a biconvex lens may be used for lens 45. Or, lenses 42 and 45 may be configured as a combination of lenses selected from biconvex lenses, plano-convex lenses, convex meniscus lenses, and concave meniscus lenses. In addition, lenses other than lenses 42 and 45 may be provided.

[0052] The photon 43 can rotate the polarization plane of the incident linearly polarized light and emit it. In one aspect of the present invention, a photon 43 with an optical rotation of 45° can be used. As the photon 43, a film-type cell containing twisted nematic liquid crystal, a polymer liquid crystal film filled with twisted nematic liquid crystal, or a Faraday rotator can be used.

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

[0054] Light that vibrates in all 360° directions emitted from the display panel 31 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 polarizer 32 passes through the reflective polarizer 41 and lens 42, which have a transmission axis of 0°, and is incident on the photon 43. In the photon 43, the polarization plane of the 0° linearly polarized light is rotated by 45°, and it is emitted as 45° linearly polarized light.

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

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

[0058] The 135° linearly polarized light emitted from the photon 43 passes through the reflective polarizer 44 and lens 45, which have a transmission axis of 135°. In this way, by utilizing linearly polarized light and photons, reflection and transmission can be selectively performed by reflective polarizers placed in the optical path. Therefore, the optical path length can be secured within a limited space, and the focal length of the optical instrument can be shortened.

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

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

[0061] Subsequently, transmission and reflection occur repeatedly in each element arranged in the optical path, but since the transmittance and reflectance of each are ideally 100% (×1), the light ultimately emitted from the lens 45 is approximately 40%. In other words, in one embodiment of the present invention, the loss of light other than that from the polarizing plate 32 is ideally 0, and it can be said that this is an optical instrument with high light utilization efficiency.

[0062] For comparison, an example of a conventional optical device is shown in Figure 3A. Elements common to both Figure 2A and Figure 3A are denoted by the same reference numerals. The optical device shown in Figure 3A, like that in Figure 2A, secures the optical path length within a limited space by repeatedly reflecting light. The optical device shown in Figure 3A differs from one embodiment of the present invention in that it uses a phase difference plate 51, a half mirror 52, a phase difference plate 53, and a reflective polarizer 54. Note that the reflective polarizer 54 has a different reflection axis and transmission axis than the reflective polarizer 44.

[0063] Here, λ / 4 plates (quarter-wave plates) are used for the phase difference plates 51 and 53. When the λ / 4 plate is superimposed with a delay axis of 45° relative to the transmission axis of the polarizer plate 32 (0°), right-rotating circular polarization is produced. The reflection axis of the reflective polarizer plate 54 is 0°, and the transmission axis is 90°.

[0064] Figure 3B is used to explain the details of the polarization state in the optical path of a conventional optical device. Figure 3B is an enlarged view of the display device 30 and optical device 40 shown in Figure 3A, with the polarization state shown in the upper optical path and the efficiency of light transmission or reflection in each element shown in the lower optical path.

[0065] Light that vibrates in all 360° directions emitted from the display panel 31 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 phase difference plate 51, becomes right-rotating circularly polarized light, and is emitted from the phase difference plate 51.

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

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

[0069] The right-rotating circularly polarized light emitted from the phase difference plate 53 is reflected by the half mirror 52 and becomes left-rotating circularly polarized light, which is then incident on the phase difference plate 53. The left-rotating circularly polarized light incident on the phase difference plate 53 becomes 90° linearly polarized light and passes through the reflective polarizer 54 and lens 45, which have a transmission axis of 90°.

[0070] Next, let's explain the light utilization efficiency. When the amount of light emitted from the display panel 31 is taken as 100%, the polarizing plate 32 absorbs light other than 0° linearly polarized light, so the amount of light emitted from the polarizing plate 32 is approximately 40% (×0.4).

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

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

[0073] Light that passes through the half mirror 52 passes through the lens 42 and phase difference plate 53, is reflected by the reflective polarizer 54, passes through the phase difference plate 53 and lens 42 again, and reaches the half mirror 52 again for reflection. Here, assuming that the transmittance of the lens 42 and 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 from the half mirror will be approximately 10% (20% × 0.5).

[0074] Subsequently, the light passes through each element arranged in the optical path, but since the transmittance of each element is ideally 100% (×1), the light ultimately emitted from lens 45 is approximately 10%. As mentioned above, the light utilization efficiency of one embodiment of the present invention is approximately 40%, which is about four times that of conventional optical devices.

[0075] Conventional optical instruments suffer particularly large light losses due to half-mirrors. In one embodiment of the present invention, a reflective polarizer is used instead of a half-mirror. Since a reflective polarizer can achieve an ideal reflectivity or transmittance of 100% for linearly polarized light, light loss can be reduced.

[0076] Furthermore, in one embodiment of the present invention, since only linearly polarized light is used and not circularly polarized light, a phase difference plate can be eliminated. Therefore, the number of optical components constituting the optical device can be reduced compared to conventional devices, and optical devices and electronic devices can be manufactured at a lower cost.

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

[0078] Figure 4A shows a modified arrangement of the reflective polarizing plate 41. The reflective polarizing plate 41 may be placed away from the lens 42, between the polarizing plate 32 and the lens 42. Alternatively, as shown in Figure 4B, the polarizing plate 32 and the reflective polarizing plate 41 may be bonded together and placed between the display panel 31 and the lens 42.

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

[0080] Furthermore, as shown in Figures 4E to 4G, it is also possible to omit the polarizing plate 32. Since both the polarizing plate 32 and the reflective polarizing plate 41 transmit 0° polarized light, the polarizing plate 32 may be omitted.

[0081] However, if there is no polarizing plate 32, when the light reflected by the reflective polarizing plate 41 returns to the display panel 31 and then heads towards the reflective polarizing plate 41 again, the polarization state of some of the light may be disrupted and pass through the reflective polarizing plate 41. Such light becomes stray light and can degrade the display quality. If there is a polarizing plate 32, the light that passes through the polarizing plate 32 is not reflected by the reflective polarizing plate 41, so stray light can be suppressed.

[0082] Figure 5A is a diagram illustrating a display panel 31 of an electronic device according to one embodiment of the present invention. The display panel 31 has a pixel array 74, a circuit 75, and a circuit 76. The pixel array 74 has pixels 70 arranged in the column direction and row direction.

[0083] Pixel 70 may 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 in which an independent operation takes place within a single "pixel" is conveniently defined as a "sub-pixel" for explanation purposes. However, "pixel" may be replaced with "region," and "sub-pixel" may be replaced with "pixel."

[0085] The sub-pixel 71 has a light-emitting device that emits visible light. Preferably, an EL element such as an OLED (Organic Light Emitting Diode) or QLED (Quantum-dot Light Emitting Diode) is used as the light-emitting device. Examples of light-emitting materials for the EL element 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 microLED (Light Emitting Diode) can be used as the light-emitting device.

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

[0087] As shown in Figure 5B, circuits 75 and 76 may be provided on layer 81, and the pixel array 74 on layer 82, so that layer 81 and layer 82 overlap. This configuration makes it possible to form a display device with a narrow bezel.

[0088] Furthermore, by placing the driver circuit in the lower layer of the pixel array 74, the wiring length can be shortened and the wiring capacitance can be reduced. Therefore, a display panel that can operate at high speed and with low power consumption can be made.

[0089] Furthermore, as shown in Figure 5B, by dividing the arrangement of circuits 75 and 76, the pixel array 74 can be partially driven. For example, partial rewriting of image data in the pixel array 74 can be performed. Also, the pixel array 74 can be operated at partially different operating frequencies.

[0090] Note that the arrangement and area of ​​circuits 75 and 76 shown in Figure 5B are examples and can be changed as appropriate. Also, parts of circuits 75 and 76 can be formed on the same layer as the pixel array 74. Furthermore, layers 82 may be provided with circuits such as memory circuits, arithmetic circuits, and communication circuits.

[0091] For example, in this configuration, layer 81 may be a single-crystal silicon substrate, circuits 75 and 76 may be formed using transistors having silicon in the channel formation region (hereinafter referred to as Si transistors), and the pixel circuits of the pixel array 74 provided on layer 82 may be formed using transistors having metal oxide in the channel formation region (hereinafter referred to as OS transistors). OS transistors can be formed as thin films and can be formed by stacking them on top of Si transistors.

[0092] As shown in Figure 5C, the configuration may also include a layer 83 between layer 81 and layer 82 on which an OS transistor is provided. In layer 83, a part of the pixel circuit of the pixel array 74 can be provided by the OS transistor. Alternatively, a part of circuit 75 and circuit 76 can be provided by the OS transistor. Alternatively, a part of the memory circuit, arithmetic circuit, and communication circuit that can be provided in layer 82 can be provided by the OS transistor.

[0093] Figures 6A and 6B show examples of glasses-type devices having the display device 30 and optical device 40 shown in Figure 1. Here, the combination of the display device 30 and optical device 40 is shown as a display unit 35, indicated by a dashed line. The glasses-type device has two sets of display units 35 and may be called VR glasses or similar depending on the application.

[0094] Two sets of display units 35 are incorporated into the housing 60 so that the surface of the lens 45 is exposed on the inside. One display unit 35 is for the right eye and the other is for the left eye, and by displaying images corresponding to each eye in each display unit 35, the user can perceive a sense of depth in the images.

[0095] Furthermore, the housing 60 or band 61 may be provided with input and output terminals. The input terminal can be connected to a cable that supplies video signals from a video output device or other device, or power to charge a battery provided inside the housing 60. The output terminal may function as an audio output terminal, for example, to which earphones, headphones, etc., can be connected. However, if the system is configured to output audio data via wireless communication, or if audio is output from an external video output device, the audio output terminal does not need to be provided.

[0096] Furthermore, a wireless communication module and a storage module may be provided inside the housing 60 or band 61. The wireless communication module allows for wireless communication, enabling the download of content to be viewed and stored in the storage module. This allows the user to view the downloaded content offline at any time.

[0097] Furthermore, a gaze detection sensor may be provided within the housing 60. For example, operation buttons such as power on, power off, sleep, volume adjustment, channel change, menu display, selection, confirmation, and back, as well as operation buttons for video playback, stop, pause, fast forward, and rewind, can be displayed, and the respective operations can be performed by visually confirming the operation buttons.

[0098] By using an optical device 40 according to one aspect of the present invention in a spectacle-type device, it is possible to create a compact, thin, low-power, and highly reliable electronic device.

[0099] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0100] (Embodiment 2) This embodiment describes an example of the configuration of a display panel that can be applied to an electronic device according to one aspect of the present invention. The display panel exemplified below can be applied to the display panel 31 of Embodiment 1 described above.

[0101] One aspect of the present invention is a display panel having light-emitting elements (also called light-emitting devices). The display panel has two or more pixels with different emission colors. Each pixel has a light-emitting element. Each light-emitting element has a pair of electrodes and an EL layer between them. The light-emitting elements are preferably organic EL elements (organic electroluminescent elements). The two or more light-emitting elements with different emission 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 manufacturing a display panel with multiple light-emitting elements, each with a different emission color, it is necessary to form at least one island-shaped layer containing the light-emitting material (light-emitting layer). When manufacturing part or all of the EL layer separately, a method of forming island-shaped organic films using a vapor deposition method with a shadow mask such as a metal mask is known. However, with this method, deviations from the design occur in the shape and position of the island-shaped organic films due to various influences such as the precision of the metal mask, the misalignment between the metal mask and the substrate, the deflection of the metal mask, and the spreading of the contour of the deposited film due to vapor scattering, making it difficult to achieve high resolution and high aperture ratio in the display panel. In addition, during vapor deposition, the contour of the layer may become blurred, and the thickness at the edges may become thinner. In other words, the thickness of the island-shaped light-emitting layer may vary depending on the location. Furthermore, when manufacturing large, high-resolution, or high-definition display panels, there is a concern that the manufacturing yield will be low due to the low dimensional accuracy of the metal mask and deformation due to heat, etc. For this reason, measures have been taken to artificially increase the resolution (also called pixel density) by adopting special pixel arrangement methods such as PenTile arrangement.

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

[0104] One aspect of the present invention involves processing the EL layer into a fine pattern using photolithography without using a shadow mask such as a fine metal mask (FMM). This makes it possible to realize a display panel with high resolution and a large aperture ratio, which has been difficult to achieve until now. Furthermore, since the EL layer can be differentiated, it is possible to realize a display panel that is extremely vivid, has high contrast, and high display quality. For example, the EL layer may be processed into a fine pattern using both a metal mask and photolithography.

[0105] Furthermore, part or all of the EL layer can be physically separated. This suppresses leakage current between light-emitting elements via a common layer (also called a common layer) used between adjacent light-emitting elements. This prevents crosstalk caused by unintended light emission, enabling the realization of a display panel with extremely high contrast. In particular, it enables the realization of a display panel with high current efficiency at low brightness levels.

[0106] One aspect of the present invention is a display panel that combines a white-emitting light-emitting element with a color filter. In this case, the same light-emitting elements can be applied to each of the pixels (sub-pixels) that emit light of different colors, and all layers can be made into a common layer. Furthermore, part or all of each EL layer may be separated by a process using photolithography. This suppresses leakage current through the common layer, enabling a display panel with high contrast. In particular, in an element having a tandem structure in which multiple light-emitting layers are stacked with a highly conductive intermediate layer in between, leakage current through the intermediate layer can be effectively prevented, thus enabling a display panel that combines high brightness, high resolution, and high contrast.

[0107] When an EL layer is processed using photolithography, a portion of the light-emitting layer may be exposed, which can lead to degradation. Therefore, it is preferable to provide an insulating layer that covers at least the sides of the island-shaped light-emitting layer. The insulating layer may also be configured to cover a portion of the upper surface of the island-shaped EL layer. It is preferable to use a material that has barrier properties against water and oxygen as the insulating layer. For example, an inorganic insulating film that does not easily diffuse water or oxygen can be used. This suppresses the degradation of the EL layer and enables the realization of a highly reliable display panel.

[0108] Furthermore, between two adjacent light-emitting elements, there is a region (recess) where neither light-emitting element has an EL layer. When a common electrode, or a common electrode and common layer, is formed to cover this recess, a phenomenon called "step break" may occur where the common electrode is separated by a step at the edge of the EL layer, and the common electrode on the EL layer may become insulated. Therefore, it is preferable to fill the local step located between two adjacent light-emitting elements with a resin layer that functions as a planarizing film (also called LFP: Local Filling Planarization). This resin layer has the function of a planarizing film. This suppresses step breaks in the common layer or common electrode, and enables the realization of a highly reliable display panel.

[0109] In the following section, a more specific example of the configuration of a display panel according to one embodiment of the present invention will be described with reference to the drawings.

[0110] [Configuration Example 1] Figure 7A shows a schematic top view of a display panel 100 according to one embodiment of the present invention. The display panel 100 has multiple red-emitting light-emitting elements 110R, green-emitting light-emitting elements 110G, and blue-emitting light-emitting elements 110B on a substrate 101. In Figure 7A, the labels R, G, and B are added within the light-emitting area of ​​each light-emitting element to simplify the distinction between them.

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

[0112] For the light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B, it is preferable to use, for example, an OLED or a QLED. Examples of light-emitting materials for the EL element include fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF) materials. Not only organic compounds but also inorganic compounds (such as quantum dot materials) can be used as light-emitting materials for the EL element.

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

[0114] The connecting electrode 111C can be provided along the outer perimeter of the display area. For example, it may be provided along one side of the outer perimeter of the display area, or it may be provided across two or more sides of the outer perimeter of the display area. That is, if the top surface shape of the display area is rectangular, the top surface shape of the connecting electrode 111C can be a strip (rectangle), L-shape, U-shape (square bracket shape), or quadrilateral, etc.

[0115] Figures 7B and 7C are schematic cross-sectional views corresponding to the dashed-dotted lines A1-A2 and A3-A4 in Figure 7A, respectively. Figure 7B shows schematic cross-sectional views of the light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B, while Figure 7C shows schematic cross-sectional view of the connection portion 140 to which the connecting electrode 111C and the 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 elements 110R, 110G, and 110B.

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

[0118] In the following, when describing matters common to the light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B, they may be referred to simply as light-emitting element 110. Similarly, for components distinguished by letters, such as organic layer 112R, organic layer 112G, and organic layer 112B, when describing matters common to them, the letters may be omitted and symbols used.

[0119] The organic layer 112 and the common layer 114 can each independently have one or more of the following: an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. For example, the organic layer 112 may have a stacked structure of a hole injection layer, a hole transport layer, an emissive layer, and an electron transport layer from the pixel electrode 111 side, and the common layer 114 may have an electron injection layer.

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

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

[0122] It is preferable that the ends of the pixel electrode 111 have a tapered shape. If the ends of the pixel electrode 111 have a tapered shape, the organic layer 112 provided along the ends of the pixel electrode 111 can also be tapered. By making the ends of the pixel electrode 111 tapered, the coverage of the organic layer 112 that extends over the ends of the pixel electrode 111 can be improved. Furthermore, making the sides of the pixel electrode 111 tapered makes it easier to remove foreign matter (for example, dust or particles) during the manufacturing process by washing or other processes, which is preferable.

[0123] In this specification, a tapered shape refers to a shape in which at least a portion of the side surface of a structure is inclined with respect to the substrate surface. For example, it is preferable to have a region in which the angle between the inclined side surface and the substrate surface (also called the taper angle) is less than 90°.

[0124] The organic layer 112 is processed into an island-like shape using photolithography. As a result, the organic layer 112 has a shape where the angle between the top surface and the side surface is close to 90 degrees at its edges. On the other hand, organic films formed using FMM (Fine Metal Mask) or the like tend to gradually become thinner towards the edges, and for example, in the range of 1 μm to 10 μm, the top surface is formed in a slope shape, making it difficult to distinguish between the top surface and the side surface.

[0125] Between two adjacent light-emitting elements, there are insulating layers 125, resin layers 126, and layers 128.

[0126] Between two adjacent light-emitting elements, the sides of each organic layer 112 are positioned opposite each other with a resin layer 126 in between. The resin layer 126 is located between the two adjacent light-emitting elements and is provided to fill the edges of each organic layer 112 and the region between the two organic layers 112. The resin layer 126 has a smooth, convex upper surface shape, and a common layer 114 and a common electrode 113 are provided covering the upper surface of the resin layer 126.

[0127] The resin layer 126 functions as a planarizing film that fills the step between two adjacent light-emitting elements. By providing the resin layer 126, it is possible to prevent the common electrode 113 from being separated by the step at the edge of the organic layer 112 (also called step breakage), and to prevent the common electrode on the organic layer 112 from becoming insulated. The resin layer 126 can also be called LFP (Local Filling Planarization).

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

[0129] Furthermore, a photosensitive resin can be used as the resin layer 126. A photoresist may 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 composed of a material that absorbs visible light, or the resin layer 126 may contain a pigment that absorbs visible light. As the resin layer 126, for example, 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 can be used.

[0131] The insulating layer 125 is provided in contact with the side surface of the organic layer 112. The insulating layer 125 also covers the upper end of the organic layer 112. Furthermore, 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 coming into contact with the organic layer 112. If the organic layer 112 and the resin layer 126 come into contact, the organic layer 112 may dissolve due to organic solvents used during the formation of 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 sides of the organic layer 112.

[0133] The insulating layer 125 can be an insulating layer having an inorganic material. For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used for the insulating layer 125. The insulating layer 125 may be a single layer or a laminated structure. Examples of oxide insulating films include silicon oxide film, aluminum oxide film, magnesium oxide film, indium gallium zinc oxide film, gallium oxide film, germanium oxide film, yttrium oxide film, zirconium oxide film, lanthanum oxide film, neodymium oxide film, hafnium oxide film, and tantalum oxide film. Examples of nitride insulating films include silicon nitride film and aluminum nitride film. Examples of oxidative nitride insulating films include silicon oxidative nitride film and aluminum oxidative nitride film. Examples of nitride oxide insulating films include silicon nitride oxide film and aluminum nitride oxide film. In particular, by applying an oxide metal film such as an aluminum oxide film or hafnium oxide film formed by the ALD method, or an inorganic insulating film such as a silicon oxide film, to the insulating layer 125, an insulating layer 125 with fewer pinholes and excellent function in protecting the EL layer can be formed.

[0134] In this specification, the term "oxide-nitride" refers to a material in which the oxygen content is greater than the nitrogen content, and the term "nitride oxide" refers to a material in which the nitrogen content is greater than the oxygen content. For example, when "silicon oxynitride" is written, it refers to a material in which the oxygen content is greater than the nitrogen content, and when "silicon nitride oxide" is written, it refers to a material in which the nitrogen content is greater than the oxygen content.

[0135] The insulating layer 125 can be formed using sputtering, CVD, PLD, ALD, or other methods. It is preferable to form the insulating layer 125 using the ALD method, which provides good coverage.

[0136] Alternatively, a reflective film (for example, a metal film containing one or more selected from silver, palladium, copper, titanium, and aluminum) may be provided between the insulating layer 125 and the resin layer 126, and the light emitted from the light-emitting layer may be reflected by the reflective film. This can improve the light extraction efficiency.

[0137] Layer 128 is formed when a portion of the protective layer (also called a mask layer or sacrificial layer) used to protect the organic layer 112 remains after etching the organic layer 112. The material used for layer 128 can be the same material used for the insulating layer 125. In particular, using the same material for both layer 128 and the insulating layer 125 is preferable because it allows for the use of common processing equipment.

[0138] In particular, metal oxide films such as aluminum oxide films and hafnium oxide films, or inorganic insulating films such as silicon oxide films, formed by the ALD method have few pinholes, and therefore have excellent protective properties for the EL layer, making them suitable for use in insulating layers 125 and 128.

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

[0140] As the protective layer 121, a laminated film of an inorganic insulating film and an organic insulating film can also be used. For example, it is preferable to have a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films. Furthermore, it is preferable that the organic insulating film functions as a planarizing film. This makes the upper surface of the organic insulating film flat, thereby improving the coverage of the inorganic insulating film on top of it and enhancing its barrier properties. In addition, since the upper surface of the protective layer 121 is flat, it is preferable because it reduces the influence of uneven shapes caused by the structure below when a structure (e.g., a color filter, touch sensor electrodes, or lens array, etc.) is provided above the protective layer 121.

[0141] Figure 7C shows a connection portion 140 where the connecting electrode 111C and the common electrode 113 are electrically connected. In the connection portion 140, openings are provided in the insulating layer 125 and the resin layer 126 on the connecting electrode 111C. The connecting electrode 111C and the common electrode 113 are electrically connected at these openings.

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

[0143] [Configuration Example 2] The following describes a display panel with some configuration differences from Configuration Example 1 described above. Note that parts common to Configuration Example 1 may be omitted from the explanation, as they are referred to in that example.

[0144] Figure 8A shows a schematic cross-sectional view of the display panel 100a. The display panel 100a differs from the display panel 100 mainly in the configuration of its light-emitting elements and in the presence of a colored layer.

[0145] The display panel 100a has a light-emitting element 110W that emits white light. The light-emitting element 110W has 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 can be configured to include two or more light-emitting materials whose emitted colors are complementary. For example, the organic layer 112W can 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, it 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] Between two adjacent light-emitting elements 110W, each organic layer 112W is separated. This suppresses leakage current flowing between adjacent light-emitting elements 110W via the organic layer 112W, thereby suppressing crosstalk caused by this leakage current. As a result, a display panel with high contrast and color reproduction can be realized.

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

[0148] As the insulating layer 122, an organic resin film or an inorganic insulating film with a flattened upper surface can be used. Since the insulating layer 122 forms the surface on which the colored layers 116R, 116G, and 116B are formed, having a flat upper surface of the insulating layer 122 allows the thickness of the colored layers 116R, etc. to be uniform, thereby improving color purity. If the thickness of the colored layers 116R, etc. is uneven, the amount of light absorbed will vary depending on the location of the colored layer 116R, which may reduce color purity.

[0149] [Configuration Example 3] Figure 8B shows a schematic cross-sectional view of the 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, conductive layer 115G, and conductive layer 115B are each light-transmitting and function as optical adjustment layers.

[0151] By using a film that reflects visible light for the pixel electrode 111 and a film that has both reflectivity and transmittance to visible light for the common electrode 113, a microcavity structure can be realized. In this case, by adjusting the thickness of the conductive layer 115R, conductive layer 115G, and conductive layer 115B to the optimal optical path length, even when using an organic layer 112 that exhibits white light emission, light with different wavelengths of light amplified can be obtained from the light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B.

[0152] Furthermore, by providing colored layers 116R, 116G, and 116B, respectively, on the optical paths of the light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B, it is possible to obtain light with high color purity.

[0153] Furthermore, an insulating layer 123 is provided to cover the edges of the pixel electrode 111 and the optical adjustment layer 115. Preferably, the insulating layer 123 has a tapered shape at its edges. By providing the insulating layer 123, the coverage by the organic layer 112W, common electrode 113, and protective layer 121 formed on it can be improved.

[0154] The organic layer 112W and the common electrode 113 are provided as a continuous film in common to each light-emitting element. This configuration is preferable because it significantly simplifies the manufacturing process of the display panel.

[0155] Here, it is preferable that the pixel electrode 111 has an end that is nearly vertical. This allows for the formation of a steeply sloped portion on the surface of the insulating layer 123, which in turn allows for the formation of a thinner portion in a part of the organic layer 112W covering this portion, or allows for the division of a part of the organic layer 112W. Therefore, leakage current through the organic layer 112W between adjacent light-emitting elements can be suppressed without processing the organic layer 112W using methods such as photolithography.

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

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

[0158] Furthermore, the top surface shape of the sub-pixel can be, for example, a polygon such as a triangle, quadrilateral (including rectangles and squares), or pentagon, or a polygon with rounded corners, or an ellipse or a circle. 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] The pixel 150 shown in Figure 9A has an S-stripe array applied to it. The pixel 150 shown in Figure 9A is composed of three subpixels: light-emitting elements 110a, 110b, and 110c. For example, light-emitting element 110a may be a blue light-emitting element, light-emitting element 110b may be a red light-emitting element, and light-emitting element 110c may be a green light-emitting element.

[0160] The pixel 150 shown in Figure 9B has a light-emitting element 110a with a roughly trapezoidal or triangular top surface shape with rounded corners, a light-emitting element 110b with a roughly trapezoidal or triangular top surface shape with rounded corners, and a light-emitting element 110c with a roughly square or hexagonal top surface shape with rounded corners. Furthermore, light-emitting element 110a has a larger light-emitting area than light-emitting element 110b. Thus, the shape and size of each light-emitting element can be determined independently. For example, the more reliable a light-emitting element is, the smaller its size can be. For example, light-emitting element 110a may be a green light-emitting element, light-emitting element 110b may be a red light-emitting element, and light-emitting element 110c may be a blue light-emitting element.

[0161] A Pentile array is applied to pixels 124a and 124b shown in Figure 9C. Figure 9C shows an example in which pixels 124a having light-emitting elements 110a and 110b and pixels 124b having light-emitting elements 110b and 110c are arranged alternately. 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.

[0162] Pixels 124a and 124b shown in Figures 9D and 9E employ a delta array. Pixel 124a has two light-emitting elements (elementary elements 110a and 110b) in the top row (1st row) and one light-emitting element (elementary element 110c) in the bottom row (2nd row). Pixel 124b has one light-emitting element (elementary element 110c) in the top row (1st row) and two light-emitting elements (elementary elements 110a and 110b) in the bottom row (2nd row). For example, elementary element 110a may be a red light-emitting element, elementary element 110b may be a green light-emitting element, and elementary element 110c may be a blue light-emitting element.

[0163] Figure 9D shows an example where each light-emitting element has a roughly rectangular top shape with rounded corners, and Figure 9E shows an example where each light-emitting element has a circular top shape.

[0164] Figure 9F shows an example where light-emitting elements of each color are arranged in a zigzag pattern. Specifically, in a top view, the upper edges of two light-emitting elements arranged in a row (for example, 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 a green light-emitting element, and light-emitting element 110c a blue light-emitting element.

[0165] In photolithography, the finer the pattern to be processed, the more significant the effects of light diffraction become. This compromises the fidelity of transferring the pattern to the photomask through exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, patterns with rounded corners are likely to form. Consequently, the top surface shape of the light-emitting element may be a polygon with rounded corners, an ellipse, or a circle.

[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 EL layer material and the curing temperature of the resist material, the curing of the resist film may be insufficient. A resist film that is not sufficiently cured may take 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, or a circle. For example, if an attempt is made to form a resist mask with a square top surface, a resist mask with a circular top surface may be formed, resulting in a circular top surface shape for the EL layer.

[0167] Furthermore, in order to achieve the desired shape of the upper surface of the EL layer, a technique (OPC (Optical Proximity Correction) technique) may be used to pre-correct the mask pattern so that the design pattern and the transferred pattern match. Specifically, in the OPC technique, a correction pattern is added to the corners of the shape on the mask pattern.

[0168] The above is an explanation of pixel layout.

[0169] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0170] (Embodiment 3) This embodiment describes other configuration examples of a display panel that can be applied to an electronic device according to one aspect of the present invention.

[0171] The display panel of this embodiment is a high-definition display panel and is particularly suitable for use in 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] [Display Module] Figure 10A shows a perspective view of the display module 280. The display module 280 includes a display panel 200A and an FPC 290. Note that the display panel of the display module 280 is not limited to display panel 200A, but may be any of the display panels 200B to 200F described later.

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

[0174] Figure 10B shows a schematic perspective view illustrating the configuration of the substrate 291. On the substrate 291, a circuit section 282, a pixel circuit section 283 on the circuit section 282, and a pixel section 284 on the pixel circuit section 283 are stacked. In addition, a terminal section 285 for connecting to the FPC 290 is provided in the portion of the substrate 291 that does not overlap with the pixel section 284. The terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286, which is composed of multiple wires.

[0175] The pixel section 284 has a plurality of pixels 284a arranged periodically. A magnified view of one pixel 284a is shown on the right side of Figure 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 section 283 has a plurality of periodically arranged pixel circuits 283a. Each pixel circuit 283a is a circuit that controls the light emission of three light-emitting devices that one pixel 284a has. A single pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting device. For example, each pixel circuit 283a can be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitive element 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 type display panel.

[0177] The circuit section 282 has circuits for driving each pixel circuit 283a of the pixel circuit section 283. For example, it is preferable to have one or both of a gate line drive circuit and a source line drive circuit. In addition, it may have at least one of the following: an arithmetic circuit, a memory circuit, and a power supply circuit. Furthermore, transistors provided in the circuit section 282 may constitute a part of the pixel circuit 283a. That is, the pixel circuit 283a may be composed of transistors in the pixel circuit section 283 and transistors in the circuit section 282.

[0178] The FPC290 functions as wiring for supplying video signals and power potential to the circuit section 282 from an external source. An IC may also be mounted on the FPC290.

[0179] The display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are superimposed on the lower side of the pixel section 284, thereby enabling an extremely high aperture ratio (effective display area ratio) of the display section 281. For example, the aperture ratio of the display section 281 can be 40% or more and less than 100%, preferably 50% or more and 95%, and more preferably 60% or more and 95%. Furthermore, it is possible to arrange the pixels 284a at an extremely high density, enabling an extremely high resolution of the display section 281. For example, it is preferable that the pixels 284a in the display section 281 are arranged with a resolution of 20000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and with a resolution of 20000 ppi or less, or 30000 ppi or less.

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

[0181] [Display Panel 200A] The display panel 200A shown in Figure 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 Figures 10A and 10B.

[0183] The transistor 310 is a transistor having a channel-forming region in the substrate 301. The substrate 301 can be a semiconductor substrate such as a single-crystal silicon substrate. The transistor 310 comprises a portion 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 of the substrate 301 doped with impurities and functions as either a source or a drain. The insulating layer 314 is provided covering the 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] Furthermore, an insulating layer 261 is provided covering the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

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

[0187] The conductive layer 241 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is electrically connected to either the source or drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided covering the conductive layer 241. The conductive layer 245 is provided in the region that overlaps with the conductive layer 241 via the insulating layer 243.

[0188] An insulating layer 255a is provided covering the capacitance 240, an insulating layer 255b is provided on the insulating layer 255a, and an insulating layer 255c is provided on the insulating layer 255b.

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

[0190] A light-emitting element 110R, a light-emitting element 110G, and a light-emitting element 110B are provided on the insulating layer 255c. The configuration of the light-emitting elements 110R, 110G, and 110B can be found in Embodiment 1.

[0191] The display panel 200A uses different light-emitting devices for each light-emitting color, resulting in minimal chromaticity changes between low-brightness and high-brightness illumination. Furthermore, because the organic layers 112R, 112G, and 112B are separated, crosstalk between adjacent sub-pixels can be suppressed even in high-resolution display panels. Therefore, a high-resolution display panel with high display quality can be realized.

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

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

[0194] Furthermore, a protective layer 121 is provided on the light-emitting elements 110R, 110G, and 110B. The substrate 170 is bonded to the protective layer 121 by an adhesive layer 171.

[0195] There is no insulating layer covering the upper edge of the pixel electrode 111 between two adjacent pixel electrodes 111. Therefore, the spacing between adjacent light-emitting elements can be made extremely narrow. Consequently, a high-definition or high-resolution display panel can be made.

[0196] [Display Panel 200B] The display panel 200B shown in Figure 12 has a configuration in which transistors 310A and 310B, each with a channel formed on a semiconductor substrate, are stacked. In the following description of the display panel, parts that are the same as those described earlier may be omitted.

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

[0198] Here, an insulating layer 345 is provided on the underside of substrate 301B, and an insulating layer 346 is provided on top of the insulating layer 261 provided on substrate 301A. Insulating layers 345 and 346 are insulating layers that function as protective layers and can suppress the diffusion of impurities into substrates 301B and 301A. As insulating layers 345 and 346, inorganic insulating films that can be used for the protective layer 121 can be used.

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

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

[0201] On the other hand, the substrate 301A has a conductive layer 341 on top of 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 conductive layer 341 and conductive layer 342. For example, a metal film containing an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, or a metal nitride film (titanium nitride film, molybdenum nitride film, tungsten nitride film) composed of the above elements can be used. In particular, it is preferable to use copper for conductive layer 341 and conductive layer 342. This makes it possible to apply Cu-Cu (copper-copper) direct bonding technology (a technology that achieves electrical conductivity by connecting Cu (copper) pads to each other).

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

[0204] As shown in Figure 13, the conductive layer 341 and the conductive layer 342 can be electrically connected by providing a bump 347 between them. The bump 347 can be formed using a conductive material including, for example, gold (Au), nickel (Ni), indium (In), or tin (Sn). Solder may also be used as the bump 347. An adhesive layer 348 may also be provided between the insulating layer 345 and the insulating layer 346. Furthermore, when the bump 347 is provided, the insulating layer 335 and the insulating layer 336 may be omitted.

[0205] [Display Panel 200D] The display panel 200D shown in Figure 14 differs from the display panel 200A mainly in its transistor configuration.

[0206] Transistor 320 is an OS transistor in which a metal oxide (also called an oxide semiconductor) is applied to the semiconductor layer where the channel is formed.

[0207] The transistor 320 has 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 Figures 10A and 10B.

[0209] An insulating layer 332 is provided on the 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 detaching from the semiconductor layer 321 to the insulating layer 332. As the insulating layer 332, for example, a film that is less susceptible to hydrogen or oxygen diffusion than a silicon oxide film can be used, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0210] A conductive layer 327 is provided on an insulating layer 332, and an insulating layer 326 is provided covering the conductive layer 327. The conductive layer 327 functions as the first gate electrode of the transistor 320, and a portion of the insulating layer 326 functions as the first gate insulating layer. It is preferable to use an oxide insulating film, such as a silicon oxide film, for at least the portion of the insulating layer 326 that is in contact with the semiconductor layer 321. It is preferable that the upper surface of the insulating layer 326 is flattened.

[0211] The semiconductor layer 321 is provided on the insulating layer 326. Preferably, the semiconductor layer 321 has a metal oxide (also called an oxide semiconductor) film that exhibits semiconductor properties. A pair of conductive layers 325 are provided in contact with the semiconductor layer 321 and function as a source electrode and a drain electrode.

[0212] An insulating layer 328 is provided covering the top and side surfaces of a pair of conductive layers 325, as well as the side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided on top of the insulating layer 328. The insulating layer 328 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing into the semiconductor layer 321 from the insulating layer 264, etc., and to prevent oxygen from detaching from the semiconductor layer 321. An insulating film similar to that of the insulating layer 332 can be used as the insulating layer 328.

[0213] The insulating layer 328 and the insulating layer 264 are provided with openings that reach the semiconductor layer 321. An insulating layer 323 in contact with the upper surface of the semiconductor layer 321 and a conductive layer 324 are embedded inside these openings. 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 flattened so that their heights are the same or approximately the same, and the insulating layer 329 and insulating layer 265 are provided covering them.

[0215] Insulating layers 264 and 265 function as interlayer insulating layers. Insulating layer 329 functions as a barrier layer to prevent impurities such as water or hydrogen from diffusing into the transistor 320 from insulating layer 265, etc. As insulating layer 329, an insulating film similar to that used for insulating layers 328 and 332 can be used.

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

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

[0218] The transistor 320 employs a configuration in which a semiconductor layer on which a channel is formed is sandwiched between two gates. The transistor may be driven by connecting the two gates and supplying them with the same signal. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential to control the threshold voltage to one of the two gates and a potential to drive the other gate.

[0219] The crystallinity of the semiconductor material used in the semiconductor layer of the transistor is not particularly limited; amorphous semiconductors, single-crystal semiconductors, or semiconductors with crystalline properties other than single crystals (microcrystalline semiconductors, polycrystalline semiconductors, or semiconductors having crystalline regions in part) may be used. Using a single-crystal semiconductor or a semiconductor with crystalline properties is preferable because it can suppress the degradation of transistor characteristics.

[0220] The band gap of the metal oxide used in the semiconductor layer of the transistor is preferably 2 eV or more, and more preferably 2.5 eV or more. By using a metal oxide with a large band gap, the off-current of the OS transistor can be reduced.

[0221] The metal oxide preferably contains at least indium or zinc, and more preferably indium and zinc. For example, the metal oxide preferably contains indium, M (where 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. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystal silicon).

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

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

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

[0226] For example, when describing a composition with an atomic ratio of In:Ga:Zn = 4:2:3 or a similar ratio, it includes cases where, when In is set to 4, Ga is between 1 and 3, and Zn is between 2 and 4. Also, when describing a composition with an atomic ratio of In:Ga:Zn = 5:1:6 or a similar ratio, it includes cases where, when In is set to 5, Ga is greater than 0.1 and 2 or less, and Zn is between 5 and 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn = 1:1:1 or a similar ratio, it includes cases where, when In is set to 1, Ga is greater than 0.1 and 2 or less, and Zn is greater than 0.1 and 2 or less.

[0227] Furthermore, the semiconductor layer may have two or more metal oxide layers with different compositions. For example, a laminated structure can be suitably used in which a first metal oxide layer has a composition of In:M:Zn=1:3:4 [atomic ratio] or close to that, and a second metal oxide layer provided on the first metal oxide layer has a composition of In:M:Zn=1:1:1 [atomic ratio] or close to that. In addition, it is particularly preferable to use gallium or aluminum as element M.

[0228] Alternatively, a layered structure may be used, for example, one selected from indium oxide, indium gallium oxide, and IGZO, and one selected from IAZO, IAGZO, and ITZO®.

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

[0230] OS transistors have extremely high field-effect mobility compared to transistors using amorphous silicon. Furthermore, OS transistors exhibit remarkably low source-drain leakage current (hereinafter also referred to as off-current) in the off state, allowing them to retain charge stored in a capacitor connected in series with the transistor for extended periods. Additionally, the application of OS transistors can reduce the power consumption of display panels.

[0231] Furthermore, to increase the luminescence brightness of the light-emitting device included in the 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 the drive transistor included in the pixel circuit. Compared to Si transistors, OS transistors have a higher breakdown voltage between the source and drain, so a higher voltage can be applied between the source and drain of an OS transistor. Therefore, by using an OS transistor as the drive transistor included in the pixel circuit, the amount of current flowing through the light-emitting device can be increased, thereby increasing the luminescence brightness of the light-emitting device.

[0232] Furthermore, when the transistor operates in the saturation region, OS transistors exhibit a smaller change in source-drain current in response to changes in gate-source voltage compared to Si transistors. Therefore, by using OS transistors as driving transistors in the pixel circuit, the current flowing between the source and drain can be precisely controlled by changes in gate-source voltage, thereby controlling the amount of current flowing to the light-emitting device. This allows for a wider range of tonal gradations in the pixel circuit.

[0233] Furthermore, in terms of the saturation characteristics of the current flowing when a transistor operates in the saturation region, OS transistors can supply a more stable current (saturation current) than Si transistors, even when the source-drain voltage gradually increases. Therefore, by using OS transistors as driving transistors, a stable current can be supplied to the light-emitting device even if there are variations in the current-voltage characteristics of the EL device. In other words, when operating in the saturation region, the source-drain current remains almost unchanged even when the source-drain voltage is increased, thus stabilizing the luminescence brightness of the light-emitting device.

[0234] As described above, by using OS transistors in the drive transistors included in the pixel circuit, it is possible to achieve "suppression of black level floating," "increase in luminescence brightness," "multi-gradation," and "suppression of variations in light-emitting devices."

[0235] [Display Panel 200E] The display panel 200E shown in Figure 15 has a configuration in which transistors 320A and 320B, each having an oxide semiconductor in the semiconductor where the channel is formed, are stacked.

[0236] For details regarding transistors 320A and 320B, and their surrounding configurations, please refer to the display panel 200D described above.

[0237] In this example, we have used a configuration in which two transistors having oxide semiconductors are stacked, but this is not the only option. For example, a configuration in which three or more transistors are stacked may also be used.

[0238] [Display Panel 200F] The display panel 200F shown in Figure 16 has a configuration in which a transistor 310 with a channel formed on a substrate 301 and a transistor 320 containing a metal oxide in the semiconductor layer where the channel is formed are stacked.

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

[0240] Transistor 320 can be used as a transistor constituting a pixel circuit. Transistor 310 can also be used as a transistor constituting a pixel circuit, or as a transistor constituting a drive circuit (gate line drive circuit, source line drive circuit) for driving the pixel circuit. Furthermore, transistors 310 and 320 can be used as transistors constituting various circuits such as arithmetic circuits or memory circuits.

[0241] This configuration allows for the formation of not only pixel circuits but also drive circuits directly beneath the light-emitting device, making it possible to miniaturize the display panel compared to cases where the drive circuits are located around the display area.

[0242] [Display Panel 200G] The display panel 200G shown in Figure 17 has a configuration in which a transistor 310 with a channel formed on a substrate 301, and transistors 320A and 320B containing a metal oxide in the semiconductor layer where the channel is formed are stacked.

[0243] Transistor 320A can be used as a transistor constituting a pixel circuit. Transistor 310 can be used as a transistor constituting a pixel circuit, or as a transistor constituting a drive circuit (gate line drive circuit, source line drive circuit) for driving the pixel circuit. Transistor 320B may be used as a transistor constituting a pixel circuit, or as a transistor constituting the above-mentioned drive circuit. Furthermore, transistors 310, 320A, and 320B can be used as transistors constituting various circuits such as arithmetic circuits or memory circuits.

[0244] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0245] (Embodiment 4) This embodiment describes a light-emitting device (light-emitting element) that can be used in a display panel according to one aspect of the present invention.

[0246] In this specification, devices fabricated using a metal mask or an FMM (Fine Metal Mask, a high-resolution metal mask) may be referred to as MM (Metal Mask) structured devices. Furthermore, in this specification, devices fabricated without using a metal mask or an FMM may be referred to as MML (Metal Maskless) structured devices.

[0247] In this specification, a structure in which at least the light-emitting layers are created separately for light-emitting devices with different emission wavelengths may be referred to as an SBS (Side By Side) structure. Because the SBS structure allows for the optimization of materials and configuration for each light-emitting device, it increases the freedom of material and configuration selection, making it easier to improve brightness and reliability.

[0248] In this specification, holes or electrons may be referred to as "carriers." Specifically, a hole injection layer or electron injection layer may be called a "carrier injection layer," a hole transport layer or electron transport layer may be called a "carrier transport layer," and a hole block layer or electron block layer may be called a "carrier block layer." Note that the above-mentioned carrier injection layer, carrier transport layer, and carrier block layer may not be clearly distinguishable by their cross-sectional shape or characteristics. Furthermore, a single layer may combine the functions of two or three of these carrier injection, carrier transport, and carrier block layers.

[0249] In this specification, a light-emitting device (also called a light-emitting element) has an EL layer between a pair of electrodes. The EL layer has at least a light-emitting layer. Examples of the layers (also called functional layers) of the EL layer include a light-emitting layer, a carrier injection layer (hole injection layer and electron injection layer), a carrier transport layer (hole transport layer and electron transport layer), and a carrier blocking layer (hole blocking layer and electron blocking layer).

[0250] As the light-emitting device, it is preferable to use, for example, an OLED or a QLED. Examples of light-emitting materials for the light-emitting device include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence (TADF) materials, and inorganic compounds (quantum dot materials, etc.). In addition, LEDs such as microLEDs can also be used as the light-emitting device.

[0251] The light-emitting device can emit light in the following colors: infrared, red, green, blue, cyan, magenta, yellow, or white. Furthermore, the color purity can be improved by adding a microcavity structure to the light-emitting device.

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

[0253] The light-emitting layer 771 has at least a light-emitting substance (also called a light-emitting material).

[0254] When the lower electrode 761 is the anode and the upper electrode 762 is the cathode, layer 780 has one or more of the following: a layer containing a material with high hole injection properties (hole injection layer), a layer containing a material with high hole transport properties (hole transport layer), and a layer containing a material with high electron blocking properties (electron blocking layer). Similarly, layer 790 has one or more of the following: a layer containing a material with high electron injection properties (electron injection layer), a layer containing a material with high electron transport properties (electron transport layer), and a layer containing a material with high hole blocking properties (hole blocking layer). When the lower electrode 761 is the cathode and the upper electrode 762 is the anode, layers 780 and 790 have the opposite configurations to those described above.

[0255] A configuration having a layer 780, an emissive layer 771, and a layer 790 provided between a pair of electrodes can function as a single emissive unit, and in this specification, the configuration shown in Figure 18A is referred to as a single structure.

[0256] Furthermore, Figure 18B shows a modified example of the EL layer 763 of the light-emitting device shown in Figure 18A. Specifically, the light-emitting device shown in Figure 18B has a layer 781 on the 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 the anode and the upper electrode 762 is the cathode, for example, layer 781 can be a hole injection layer, layer 782 a hole transport layer, layer 791 an electron transport layer, and layer 792 an electron injection layer. Also, when the lower electrode 761 is the cathode and the upper electrode 762 is the anode, layer 781 can be an electron injection layer, layer 782 an electron transport layer, layer 791 a hole transport layer, and layer 792 a hole injection layer. By using such a layer structure, carriers can be efficiently injected into the light-emitting layer 771, and the efficiency of carrier recombination within the light-emitting layer 771 can be increased.

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

[0259] Furthermore, as shown in Figures 18E and 18F, a configuration in which multiple light-emitting units (light-emitting units 763a and 763b) are connected in series via a charge generation layer 785 (also called an intermediate layer) is referred to as a tandem structure in this specification. The tandem structure may also be called a stacked structure. By using a tandem structure, a light-emitting device capable of high-brightness emission can be created. In addition, compared to a single structure, the tandem structure can reduce the current required to obtain the same brightness, thereby improving reliability.

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

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

[0262] In Figures 18C and 18D, the 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 materials that emit blue light may be used for the light-emitting layers 771, 772, and 773. In subpixels that emit blue light, the blue light emitted by the light-emitting device can be extracted. In subpixels that emit red light and subpixels that emit green light, a color conversion layer is provided as layer 764 as shown in Figure 18D, which converts the blue light emitted by the light-emitting device into longer wavelength light, allowing for the extraction of red or green light.

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

[0264] For example, if a single-structure light-emitting device has three light-emitting layers, it is preferable that it has a light-emitting layer having a light-emitting material that emits red (R) light, a light-emitting layer having a light-emitting material that emits green (G) light, and a light-emitting layer having 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] Furthermore, for example, if a single-structure light-emitting device has two light-emitting layers, it is preferable that it has a light-emitting layer having a light-emitting material that emits blue (B) light and a light-emitting layer having a light-emitting material that emits yellow light. This configuration may be referred to as BY single.

[0266] A color filter may be provided as layer 764, as shown in Figure 18D. By passing white light through the color filter, light of the 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, one should select light-emitting materials such that the light emitted by each of the two or more materials is complementary in color. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary, a light-emitting device that emits white light as a whole can be obtained. The same applies to light-emitting devices that have three or more light-emitting layers.

[0268] Furthermore, in Figures 18E and 18F, the light-emitting layer 771 and the light-emitting layer 772 may be made of light-emitting materials that emit light of the same color, or even the same light-emitting material.

[0269] For example, in a light-emitting device having subpixels that emit light of each color, light-emitting materials that emit blue light may be used in the light-emitting layer 771 and the light-emitting layer 772, respectively. In the subpixels that emit blue light, the blue light emitted by the light-emitting device can be extracted. In addition, in the subpixels that emit red light and the subpixels that emit green light, a color conversion layer is provided as layer 764 as shown in Figure 18F, which converts the blue light emitted by the light-emitting device into longer wavelength light, allowing red or green light to be extracted.

[0270] Furthermore, when using light-emitting devices with the configuration shown in Figure 18E or Figure 18F for sub-pixels that emit light of each color, different light-emitting materials may be used for each sub-pixel. Specifically, in a light-emitting device for a sub-pixel that emits red light, light-emitting materials that emit red light may be used for both the light-emitting layer 771 and the light-emitting layer 772. Similarly, in a light-emitting device for a sub-pixel that emits green light, light-emitting materials that emit green light may be used for both the light-emitting layer 771 and the light-emitting layer 772. In a light-emitting device for a sub-pixel that emits blue light, light-emitting materials that emit blue light may be used for both the light-emitting layer 771 and the light-emitting layer 772. A display panel with such a configuration can be said to have a tandem structure light-emitting device and an SBS structure. Therefore, it can combine the advantages of both the tandem structure and the SBS structure. This enables high-brightness light emission and realizes a highly reliable light-emitting device.

[0271] Furthermore, in Figures 18E and 18F, different luminescent materials with different emission colors may be used for the luminescent layer 771 and the luminescent layer 772. When the light emitted by the luminescent layer 771 and the light emitted by the luminescent layer 772 are complementary colors, white light emission is obtained. A color filter may be provided as layer 764 as shown in Figure 18F. By passing white light through the color filter, light of a desired color can be obtained.

[0272] In Figures 18E and 18F, examples are shown 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 the design is not limited to this. The light-emitting unit 763a and the light-emitting unit 763b may each have two or more light-emitting layers.

[0273] Furthermore, while Figures 18E and 18F illustrate a light-emitting device having two light-emitting units, the device is not limited to this. A light-emitting device may have three or more light-emitting units.

[0274] Specifically, the configuration of the light-emitting device shown in Figures 19A to 19C is an example.

[0275] Figure 19A shows a configuration with three light-emitting units. A configuration with two light-emitting units may also be referred to as a two-stage tandem structure, and a configuration with three light-emitting units may be referred to as a three-stage tandem structure.

[0276] Furthermore, as shown in Figure 19A, the configuration is such that multiple light-emitting units (light-emitting unit 763a, light-emitting unit 763b, and light-emitting unit 763c) are connected in series via a charge generation layer 785. Light-emitting unit 763a has layer 780a, light-emitting layer 771, and layer 790a; light-emitting unit 763b has layer 780b, light-emitting layer 772, and layer 790b; and light-emitting unit 763c has layer 780c, light-emitting layer 773, and layer 790c.

[0277] In the configuration shown in Figure 19A, it is preferable that the light-emitting layers 771, 772, and 773 each have a light-emitting material that emits light of the same color. Specifically, the configuration can be such that the light-emitting layers 771, 772, and 773 each have a red (R) light-emitting material (a so-called R\R\R three-stage tandem structure), the light-emitting layers 771, 772, and 773 each have 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 each have a blue (B) light-emitting material (a so-called B\B\B three-stage tandem structure).

[0278] Note that the light-emitting substances that emit light of the same color are not limited to the above configuration. For example, as shown in FIG. 19B, a tandem-type light-emitting device in which light-emitting units having a plurality of light-emitting substances are stacked may be used. FIG. 19B shows 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. Further, the light-emitting unit 763a includes a layer 780a, light-emitting layers 771a, 771b, and 771c, and a layer 790a, and the light-emitting unit 763b includes a layer 780b, light-emitting layers 772a, 772b, and 772c, and a layer 790b.

[0279] In the configuration shown in FIG. 19B, the light-emitting layers 771a, 771b, and 771c are configured to be capable of emitting white light (W) by selecting light-emitting substances having a complementary color relationship. Further, the light-emitting layers 772a, 772b, and 772c are configured to be capable of emitting white light (W) by selecting light-emitting substances having a complementary color relationship. That is, in the configuration shown in FIG. 19C, it is a two-stage tandem structure of W\W. Note that the stacking order of the light-emitting substances having a complementary color relationship in the light-emitting layers 771a, 771b, and 771c is not particularly limited. The implementer can appropriately select an optimal stacking order. Although not shown, a three-stage tandem structure of W\W\W or a tandem structure of four or more stages may be used.

[0280] In addition, when using a tandem-structured light-emitting device, 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 B\Y\B three-stage tandem structure having 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 in this order, a B\YG\B three-stage tandem structure having 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 in this order, a B\G\B three-stage tandem structure having 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 in this order, and the like.

[0281] In addition, 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] Specifically, in the configuration shown in FIG. 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 a charge generation layer 785. Further, the light-emitting unit 763a has a layer 780a, a light-emitting layer 771, and a layer 790a, the light-emitting unit 763b has a layer 780b, light-emitting layers 772a, 772b, and 772c, and a layer 790b, and the light-emitting unit 763c has a layer 780c, a light-emitting layer 773, and a layer 790c.

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

[0284] For example, the number of layers and color order of the light-emitting unit 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, B, or a three-layer structure of B, X, B. The number of layers and color order of the light-emitting layers in light-emitting unit X 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, G, or a three-layer structure of R, G, R. In addition, other layers may be provided between the two light-emitting layers.

[0285] Furthermore, in Figures 18C and 18D, as shown in Figure 18B, layer 780 and layer 790 may each be independently constructed as a laminated structure consisting of two or more layers.

[0286] Furthermore, in Figures 18E and 18F, the light-emitting unit 763a has layer 780a, light-emitting layer 771, and layer 790a, and the light-emitting unit 763b has layer 780b, light-emitting layer 772, and layer 790b.

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

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

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

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

[0291] Of the lower electrode 761 and upper electrode 762, the electrode that extracts light preferably uses a conductive film that transmits visible light. Furthermore, it is preferable to use a conductive film that reflects visible light on the electrode that does not extract light. In addition, if the display panel has a light-emitting device that emits infrared light, it is preferable to use a conductive film that transmits both visible and infrared light on the electrode that extracts light, and a conductive film that reflects both visible and infrared light on the electrode that does not extract light.

[0292] Furthermore, a conductive film that transmits visible light may also be used on the electrode that does not extract light. In this case, it is preferable to place the electrode between the reflective layer and the EL layer 763. In other words, the light emitted from the EL layer 763 may be reflected by the reflective layer and extracted from the display panel.

[0293] As materials for forming a pair of electrodes in a light-emitting device, metals, alloys, electrically conductive compounds, and mixtures thereof can be used as appropriate. Specifically, 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, and alloys containing these in appropriate combinations. Other examples of such materials include indium tin oxide (In-Sn oxide, also called ITO), In-Si-Sn oxide (also called ITSO), indium zinc oxide (In-Zn oxide), and In-W-Zn oxide. Furthermore, examples of such materials include aluminum-containing alloys (aluminum alloys) such as aluminum, nickel, and lanthanum alloys (Al-Ni-La), and silver, palladium, and copper alloys (Ag-Pd-Cu, also written as APC). Other materials include elements belonging to Group 1 or Group 2 of the periodic table not exemplified above (e.g., lithium, cesium, calcium, strontium), rare earth metals such as europium and ytterbium, alloys containing these in appropriate combinations, graphene, and the like.

[0294] It is preferable that the light-emitting device has a microcavity structure. Therefore, it is preferable that one of the pair of electrodes in the light-emitting device is a semitransmitting / semi-reflective electrode that is transparent to and reflective to visible light, and the other is a reflective electrode that is reflective to visible light. By having a microcavity structure in the light-emitting device, the light emitted from the light-emitting layer can be resonated between the two electrodes, thereby strengthening the light emitted from the light-emitting device.

[0295] Furthermore, the semi-transparent / semi-reflective electrode can have a laminated structure consisting of a conductive layer that can be used as a reflective electrode and a conductive layer that can be used as an electrode that transmits visible light (also called a transparent electrode).

[0296] The light transmittance of the transparent electrode shall be 40% or more. For example, it is preferable to use an electrode with a transmittance of 40% or more for visible light (light with a wavelength of 400 nm or more and less than 750 nm) for the transparent electrode of a light-emitting device. The visible light reflectance of the semi-transparent / semi-reflective electrode shall be 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. The resistivity of these electrodes shall be 1 × 10⁻⁶ -2 A value of Ωcm or less is preferable.

[0297] A light-emitting device has at least a light-emitting layer. Furthermore, a light-emitting device may have layers other than the light-emitting layer, including materials with high hole injection properties, materials with high hole transport properties, hole-blocking materials, materials with high electron transport properties, electron-blocking materials, materials with high electron injection properties, or bipolar materials (materials with high electron and hole transport properties). For example, a light-emitting device can have a configuration that includes, in addition to the light-emitting layer, one or more layers from among a hole injection layer, a hole transport layer, a hole-blocking layer, a charge generation layer, an electron-blocking layer, an electron transport layer, and an electron injection layer.

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

[0299] The light-emitting layer has one or more light-emitting substances. As the light-emitting substance, a substance exhibiting a light-emitting color such as blue, purple, blue-violet, green, yellow-green, yellow, orange, or red is appropriately used. Also, a substance that emits near-infrared light can be used as the light-emitting substance.

[0300] Examples of the light-emitting substance include a fluorescent material, a phosphorescent material, a TADF material, and a quantum dot material.

[0301] Examples of the fluorescent material include a pyrene derivative, an anthracene derivative, a triphenylene derivative, a fluorene derivative, a carbazole derivative, a dibenzothiophene derivative, a dibenzofuran derivative, a dibenzoquinoxaline derivative, a quinoxaline derivative, a pyridine derivative, a pyrimidine derivative, a phenanthrene derivative, and a naphthalene derivative.

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

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

[0304] The light-emitting layer preferably comprises, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that readily forms an excitation complex. This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excitation complex to the light-emitting substance (phosphorescent material). By selecting a combination that forms an excitation complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the light-emitting substance, energy transfer becomes smoother, and light emission can be obtained efficiently. This configuration simultaneously achieves high efficiency, low-voltage operation, and a long lifespan for the light-emitting device.

[0305] The hole injection layer is a layer that injects holes from the anode into the hole transport layer, and is a layer containing a material with high hole injection capabilities. Examples of materials with high hole injection capabilities include aromatic amine compounds and composite materials containing hole transport materials and acceptor materials (electron-accepting materials).

[0306] As the hole-transporting material, a material with high hole-transporting properties that can be used in the hole-transporting layer, as described later, can be used.

[0307] As acceptor materials, for example, oxides of metals belonging to groups 4 through 8 of the periodic table can be used. Specifically, these 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. Organic acceptor materials containing fluorine can also be used. Furthermore, organic acceptor materials such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives can also be used.

[0308] For example, as a material with high hole injection properties, a material containing a hole transport material and an oxide of a metal belonging to Group 4 to Group 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 containing a hole-transporting material. The hole-transporting material is 1 × 10⁻¹⁶ -6 cm 2 Materials having a hole mobility of / Vs or higher are preferred. However, other materials can also be used as long as they have higher hole transport capabilities than electron transport. Preferred hole transport materials include π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, furan derivatives, etc.) and aromatic amines (compounds having an aromatic amine skeleton), which are materials with high hole transport capabilities.

[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-transporting properties and is capable of blocking electrons. Among the hole-transporting materials mentioned above, a material that has electron-blocking properties can be used for the electron blocking layer.

[0311] Because electron-blocking layers possess hole-transporting properties, they can also be called hole-transporting layers. Furthermore, among hole-transporting layers, those that exhibit electron-blocking properties can also be called electron-blocking layers.

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

[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-transporting properties and is capable of blocking holes. Among the electron-transporting materials mentioned above, a material that has hole-blocking properties can be used for the hole-blocking layer.

[0314] Because hole-blocking layers possess electron-transporting properties, they can also be called electron-transporting layers. Furthermore, among electron-transporting layers, those that exhibit hole-blocking properties can also be called hole-blocking layers.

[0315] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer, and is a layer containing a material with high electron injection capabilities. Alkali metals, alkaline earth metals, or compounds thereof can be used as materials with high electron injection capabilities. Composite materials containing both electron transport materials and donor materials (electron-donating materials) can also be used as materials with high electron injection capabilities.

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

[0317] The electron injection layer contains, for example, lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), and calcium fluoride (CaF). x , x is any number), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatritium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatritium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatritium (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 also be a multilayer structure of two or more layers. For example, a multilayer structure in which lithium fluoride is used as the first layer and ytterbium is provided as the second layer can be used.

[0318] The electron injection layer may contain an electron-transporting material. For example, a compound having a lone pair of electrons 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), or a triazine ring can be used.

[0319] Furthermore, the lowest unoccupied molecular orbital (LUMO) level of organic compounds containing lone pairs of electrons is preferably between -3.6 eV and -2.3 eV. In general, the highest occupied molecular orbital (HOMO) level and LUMO level of organic compounds can be estimated by methods such as cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy.

[0320] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as mPPhen2P), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz) can be used in organic compounds containing lone pairs of electrons. NBPhen has a higher glass transition temperature (Tg) and superior 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, and preferably contains, for example, a hole transport material and an acceptor material applicable to the hole injection layer described above.

[0322] Furthermore, the charge generation layer preferably includes a layer containing a material with high electron injection potential. This layer can 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 an electron injection buffer layer, the injection barrier between the charge generation region and the electron transport layer can be relaxed, allowing electrons generated in the charge generation region to 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 can, for example, a compound of an alkali metal or an alkaline earth metal. Specifically, the electron injection buffer layer preferably has an inorganic compound containing an alkali metal and oxygen, or an inorganic compound containing an alkaline earth metal and oxygen, and more preferably has an inorganic compound containing lithium and oxygen (such as lithium oxide (Li2O)). In addition, any other material applicable to the electron injection layer can be suitably used for the electron injection buffer layer.

[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. If 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 electron transport layer) and smoothly transferring electrons.

[0325] As 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] Furthermore, the charge generation region, electron injection buffer layer, and electron relay layer described above may not be clearly distinguishable depending on their cross-sectional shape or characteristics.

[0327] The charge generation layer may have a donor material instead of an acceptor material. For example, the charge generation layer may have a layer containing an electron transport material and a donor material, which is applicable to the electron injection layer described above.

[0328] When stacking light-emitting units, the rise in driving voltage can be suppressed by providing a charge generation layer between the two light-emitting units.

[0329] The configuration examples illustrated in this embodiment, and the corresponding drawings, etc., can be appropriately combined with other configuration examples or drawings, etc., at least in part.

[0330] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part. [Explanation of symbols]

[0331] 10: Eye, 30: Display device, 31: Display panel, 32: Polarizer, 35: Display unit, 40: Optical instrument, 41: Reflective polarizer, 42a: Lens, 42b: Lens, 42: Lens, 43: Photon, 44: Reflective polarizer, 45: Lens, 51: Phase difference plate, 52: Half mirror, 53: Phase difference plate, 54: Reflective polarizer, 60: Housing, 61: Band, 70: Pixel, 71: Sub-pixel, 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: Connecting 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: Coloring layer, 116G: Coloring layer, 116R: Coloring layer, 121: Storage Protective layer, 122: insulating layer, 123: insulating layer, 124a: pixel, 124b: pixel, 125: insulating layer, 126: resin layer, 128: layer, 140: connection part, 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: capacitance, 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 unit, 282: Circuit unit, 283a: Pixel circuit, 283: Pixel circuit unit, 284a: Pixel, 284: Pixel unit, 285: Terminal unit, 286: Wiring unit, 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. It comprises a first lens, a polarizing plate, a first reflective polarizing plate, a second lens, a photorotator, a second reflective polarizing plate, and a third lens. The first lens, the polarizer, the first reflective polarizer, the second lens, the photorotator, the second reflective polarizer, and the third lens are arranged in that order such that each has an overlapping region with respect to the others. The second lens and the photorotator are separated, The third lens is a plano-convex lens, and is positioned such that its planar side is close to the second reflective polarizer. optical equipment.

2. In claim 1, The first surface of the first reflective polarizing plate is bonded to the first surface of the polarizing plate, The second surface of the first reflective polarizing plate is bonded to the first surface of the second lens. An optical device in which the second surface of the polarizing plate is bonded to the first surface of the first lens.

3. In claim 1 or 2, The first surface of the photorotator is bonded to the first surface of the second reflective polarizer. An optical device in which the second surface of the second reflective polarizing plate, opposite to the first surface, is bonded to the plane of the third lens.

4. In claim 1 or 2, The first reflective polarizer transmits first linearly polarized light and reflects second linearly polarized light that is perpendicular to the first linearly polarized light. The second reflective polarizer is an optical device that reflects a third linearly polarized light obtained by rotating the polarization plane of the first linearly polarized light by 45°, and transmits a fourth linearly polarized light that is orthogonal to the third linearly polarized light.

5. In claim 1 or 2, The aforementioned photorotator is an optical instrument with an optical rotation of 45°.

6. In claim 1 or 2, The first lens and the second lens are convex lenses in this optical instrument.

7. The housing contains a display panel, a first lens, a polarizing plate, a first reflective polarizing plate, a second lens, a photorotator, a second reflective polarizing plate, and a third lens. The display panel, the first lens, the polarizing plate, the first reflective polarizing plate, the second lens, the photorotator, the second reflective polarizing plate, and the third lens are arranged in that order such that each has an overlapping region with respect to the others. The second lens and the photorotator are arranged at a distance from each other. The third lens is a plano-convex lens, and is positioned such that its planar side is close to the second reflective polarizer. electronic equipment.

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

9. In claim 7 or 8, The first surface of the first reflective polarizing plate is bonded to the first surface of the polarizing plate, The second surface of the first reflective polarizing plate is bonded to the first surface of the second lens. An electronic device in which the second surface of the polarizing plate is bonded to the first surface of the first lens.

10. In claim 7 or 8, The first surface of the photorotator is bonded to the first surface of the second reflective polarizer. An electronic device in which the second surface of the second reflective polarizing plate, opposite to the first surface, is bonded to the plane of the third lens.

11. In claim 7 or 8, The polarizing plate transmits the first linearly polarized light, The first reflective polarizer transmits the first linearly polarized light and reflects the second linearly polarized light that is perpendicular to the first linearly polarized light. The second reflective polarizing plate is an electronic device that reflects a third linearly polarized light obtained by rotating the polarization plane of the first linearly polarized light by 45°, and transmits a fourth linearly polarized light that is orthogonal to the third linearly polarized light.

12. In claim 7 or 8, The aforementioned photorotator is an electronic device with an optical rotation of 45°.

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

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