Electronic device

Abstract

The purpose of the present invention is to provide an electronic device capable of easily obtaining accurate line-of-sight information.　The electronic device according to the present invention includes a display panel (20), a catadioptric optical system (30), and a light source (80) that emits infrared light. The display panel (20) includes a light-emitting element and a light-receiving element in a pixel (21). The catadioptric optical system (30) forms an optical path for visible light between the surface of an eye (40) and the light-receiving element, and an optical path for infrared light between the light-emitting element and a retina (42). Between the surface of the eye (40) and the light-receiving element, a filter (24) having a shielding layer (24a) and an opening (24b) is used to limit rays of infrared light transmitting through the catadioptric optical system (30).　This enables eye imaging used for line-of-sight detection or the like with a simple configuration, similar to that of a pinhole camera.

Description

electronic equipment

[0001] One aspect of the present invention relates to electronic equipment.

[0002] It should be noted that one aspect of the present invention is not limited to the above-mentioned technical field. The technical field of one aspect of the invention disclosed herein relates to a product, a method, or a method of manufacture. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. More specifically, examples of the technical fields of one aspect of the present invention disclosed herein include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting devices, energy storage devices, memory devices, imaging devices, methods of operating them, or methods of manufacturing them.

[0003] In this specification, the term "semiconductor device" refers to any device that can function by utilizing semiconductor properties. Transistors and semiconductor circuits are examples of semiconductor devices. Furthermore, memory devices, display devices, imaging devices, and electronic devices may contain semiconductor devices.

[0004] Goggle-type devices and glasses-type devices are being developed as electronic devices for XR (a general term for virtual reality (VR), augmented reality (AR), mixed reality (MR), etc.).

[0005] Furthermore, typical examples of display panels used in these electronic devices include display devices equipped with liquid crystal elements, organic EL (Electroluminescence) elements, or light-emitting diodes (LEDs).

[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.

[0007] In addition, in a goggle-type device, an infrared light sensor may be implemented for the purpose of obtaining dynamic information of the eye or its vicinity, which is necessary for gaze detection and the like. For example, Patent Document 2 discloses an electronic device provided with a sensor function for detecting fatigue or abnormality from the blinking operation.

[0008] Japanese Patent Application Laid-Open No. 2002-324673 International Publication No. 2022 / 234383

[0009] Takashi Koiwa, "High Mobility Transparent Conductive Film", National Institute of Advanced Industrial Science and Technology, AIST Solar Power Generation Research Results Report 2019, Internet <URL: https: / / unit.aist.go.jp / rpd-envene / PV / ja / results / 2019 / oral / T13.pdf>

[0010] A sensor using infrared light with low visual sensitivity is effective for detecting information of the eye or its vicinity because it does not affect the visual recognition of an image. However, an increase in the number of parts is contrary to the miniaturization, weight reduction, and cost reduction of an electronic device. Therefore, in incorporating a light source and a sensor into an electronic device, contrivances for solving these problems are desired.

[0011] In addition, in order to improve the detection accuracy of the gaze, it is preferable to accurately detect the movement of the eyeball. It can be said that it is appropriate to acquire a frontal image of the eye in order to accurately detect the position of the eye (pupil). However, in a goggle-type device, since an optical system and a display panel are arranged in front of the eye, a light source and a sensor for acquiring an image of the eye are arranged in an oblique direction where the optical system does not interfere with the eye. Therefore, gaze information may not be accurately obtained.

[0012] Therefore, one object of an aspect of the present invention is to provide an electronic device that can easily obtain accurate gaze information. Or, one object is to provide an electronic device with a low manufacturing cost. Or, one object is to provide an electronic device including a light source, a sensor, and an optical element. Or, one object is to provide an electronic device that can detect motion information of a user's eye or in its vicinity. Or, one object is to provide a novel electronic device. Or, one object is to provide a novel semiconductor device or the like.

[0013] Note that the description of these problems does not prevent the existence of other problems. Note that one aspect of the present invention does not necessarily have to solve all of these problems. Other problems will be naturally clarified from the descriptions in the specification, drawings, claims, etc., and it is possible to extract these other problems from the descriptions in the specification, drawings, claims, etc.

[0014] One aspect of the present invention relates to an electronic device with a low manufacturing cost and that can easily obtain accurate gaze information.

[0015] One aspect of the present invention is an electronic device that has a display panel, a reflective refractive optical system, and a light source and is worn in front of a user's eye. The reflective refractive optical system is arranged to face the display surface of the display panel. The display panel has pixels each having a light-emitting element and a light-receiving element arranged adjacent to each other, and a filter. The filter has a shielding layer and an opening. The shielding layer has a function of transmitting visible light and shielding infrared light. The opening has a region that overlaps with the light-receiving element. The reflective refractive optical system has a half mirror that transmits infrared light and semi-transmits and semi-reflects visible light, a function of forming an image of visible light emitted from the light-emitting element on the retina of the eye, and a function of transmitting infrared light reflected from the surface of the eye and emitted by the light source.

[0016] The reflective refractive optical system can be configured such that a linear polarizing plate, a first retardation plate, a half mirror, a second retardation plate, and a reflective polarizing plate are arranged in this order in one direction from the display panel side.

[0017] The filter can have a resin layer that transmits infrared light in the opening.

[0018] A planarization film may be provided between the filter and the light-emitting element and the light-receiving element. Alternatively, a support substrate may be provided between the filter and the light-emitting element and the light-receiving element.

[0019] It is preferable to have a convex lens between the light-emitting element and the filter.

[0020] The shielding layer preferably comprises one or more materials selected from copper phthalocyanine, antimony phthalocyanine, aluminum chloride naphthalocyanine, oxotitanium naphthalocyanine compounds, oxovanadium naphthalocyanine, and tin chloride naphthalocyanine. Alternatively, the shielding layer is preferably a dielectric multilayer film.

[0021] Another aspect of the present invention is an electronic device worn in front of a user's eye, comprising a display panel, a reflective / refracting optical system, a filter, and a light source, wherein the reflective / refracting optical system is positioned opposite the display surface of the display panel, the filter is positioned between the display panel and the eye, the display panel has pixels having adjacently positioned light-emitting and light-receiving elements, the filter has a shielding layer and an aperture, the shielding layer has the function of transmitting visible light and shielding infrared light, and the reflective / refracting optical system has a half-mirror that transmits infrared light and semi-transmits / semi-reflects visible light, the function of imaging visible light emitted by a light-emitting element onto the retina of the eye, and the function of transmitting infrared light emitted by a light source and reflected from the surface of the eye.

[0022] The filter is positioned so as to sandwich a reflective / refracting optical system between itself and the display surface of the display panel, and the aperture can be limited to one.

[0023] Alternatively, the filter can be placed between the display surface of the display panel and the reflective / refractive optical system, and may have multiple apertures.

[0024] The reflective and refractive optical system can be configured such that a linear polarizer, a first phase difference plate, a half mirror, a second phase difference plate, and a reflective polarizer are arranged in that order in one direction from the display panel side.

[0025] Each pixel has a transistor connected to both the light-emitting element and the light-receiving element, and it is preferable that the transistor has a metal oxide in its channel-forming region. Furthermore, it is preferable that the metal oxide is indium oxide.

[0026] According to one aspect of the present invention, it is possible to provide an electronic device that makes it easy to obtain accurate gaze information. Alternatively, it is possible to provide an electronic device with low manufacturing costs. Alternatively, it is possible to provide an electronic device equipped with a light source, a sensor, and an optical element. Alternatively, it is possible to provide an electronic device that can detect movement information of the user's eyes or their vicinity. Alternatively, it is possible to provide a novel electronic device. Alternatively, it is possible to provide a novel semiconductor device, etc.

[0027] 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.

[0028] Figure 1 is a diagram illustrating electronic equipment. Figure 2 is a diagram illustrating pixels and filters. Figures 3A and 3B are diagrams illustrating reflective and refractive optical systems. Figures 4A and 4B are diagrams illustrating simulation results of shielding layers and half-mirrors. Figures 5A, 5B, 5C, 5D, 5E, 5F, and 5G are diagrams illustrating supports. Figure 6 is a diagram illustrating light rays reaching the display panel from a linear polarizer. Figures 7A and 7E are diagrams illustrating electronic equipment. Figures 7B, 7C, and 7D are diagrams illustrating filters. Figures 8A, 8B, 8C, 8D, and 8E are diagrams illustrating display panels. Figures 9A, 9B, 9C, and 9D are diagrams illustrating display panels. Figures 10A, 10B, and 10C are diagrams illustrating pixel circuits. Figure 11 is a perspective view illustrating electronic equipment. Figure 12 is a diagram illustrating an example of a display panel configuration. Figures 13A and 13B are diagrams illustrating an example of a display panel configuration. Figure 14 is a diagram illustrating an example of the display panel configuration. Figure 15 is a diagram illustrating an example of the display panel configuration. Figure 16 is a diagram illustrating an example of the display panel configuration. Figure 17 is a diagram illustrating an example of the display panel configuration. Figure 18 is a diagram illustrating an example of the display panel configuration. Figures 19A and 19B illustrate a transistor. Figures 20A and 20B illustrate the carrier concentration dependence of hole mobility. Figure 20C is a cross-sectional view illustrating an indium oxide film.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] In this specification, "connection" includes, for example, "electrical connection." The term "electrical connection" is sometimes used to describe the connection relationships of circuit elements as physical objects. Furthermore, "electrical connection" includes both "direct connection" and "indirect connection." "A and B are directly connected" means that A and B are connected without the use of circuit elements (e.g., transistors, switches, etc.; however, wiring is not considered a circuit element). On the other hand, "A and B are indirectly connected" means that A and B are connected through one or more circuit elements.

[0033] For example, assuming a circuit including A and B is in operation, if there is a timing during the circuit's operation when electrical signals are exchanged or potential interactions occur between A and B, then it can be defined that "A and B are indirectly connected" as physical objects. Furthermore, even if there is a timing during the circuit's operation when no electrical signals are exchanged or potential interactions occur between A and B, if there is a timing during the circuit's operation when electrical signals are exchanged or potential interactions occur between A and B, then it can be defined that "A and B are indirectly connected."

[0034] An example of a case where "A and B are indirectly connected" is when A and B are connected via the source and drain of one or more transistors. On the other hand, an example of a case where "A and B are not indirectly connected" is when an insulator is interposed in the path from A to B. Specifically, this includes cases where a capacitive element is connected between A and B, or where a transistor gate insulating film is interposed between A and B. Therefore, it cannot be said that "the gate (A) of a transistor and the source or drain (B) of a transistor are indirectly connected."

[0035] Another example of a situation where it cannot be said that "A and B are indirectly connected" is when multiple transistors are connected via source and drain in the path from A to B, and a constant potential V is supplied to the nodes between the transistors from a power supply, GND, etc.

[0036] (Embodiment 1) This embodiment describes an electronic device according to one aspect of the present invention.

[0037] One aspect of the present invention is an electronic device worn in front of the eye, capable of detecting dynamic information of the eye and its vicinity. The electronic device comprises a display panel, a reflective / refracting optical system, and an infrared light source. The display panel has light-emitting elements (also called light-emitting devices) and light-receiving elements (also called light-receiving devices) arranged adjacent to each other within a pixel. In the reflective / refracting optical system, an optical path involving light reflection is formed between the light-emitting elements and the retina, and an optical path through which light is transmitted is formed between the surface of the eye and the light-receiving elements.

[0038] To improve the accuracy of gaze detection, it is preferable to accurately detect (image) the movement of the eyeball. To accurately detect the position of the eye (pupil), it is appropriate to acquire a frontal image of the eye. In one aspect of the present invention, a light-receiving element is provided in the pixel of a display panel located in front of the eye, and this light-receiving element is used as a sensor for gaze detection.

[0039] Light emitted by the light-emitting elements of a pixel, which constitutes an image, can be imaged on the retina of the eye by a reflective / refracting optical system. On the other hand, the same reflective / refracting optical system cannot image light emitted from the surface of the eye (reflected light from a light source) onto the photodetector of the pixel. Therefore, in one embodiment of the present invention, light of different wavelengths is used between the surface of the eye and the photodetector, and between the light-emitting element and the retina, and the optical paths are made different.

[0040] Specifically, visible light is used between the light-emitting element and the retina, and infrared light is used between the surface of the eye and the photodetector. The reflective-refractive optical system forms an optical path of visible light with reflection and refraction between the light-emitting element and the retina. On the other hand, between the surface of the eye and the photodetector, a filter with a shielding layer and an aperture is used to limit the infrared light rays that pass through the reflective-refractive optical system. In other words, imaging can be performed with a simple configuration similar to that of a pinhole camera. Furthermore, since the shielding layer uses a material that shields infrared light and transmits visible light, interference of the shielding layer with the optical path between the light-emitting element and the retina can be avoided.

[0041] This configuration allows the light emitted by the light-emitting element to be focused on the retina, limiting the light rays emitted from the surface of the eye and directing them into the photodetector. Therefore, a frontal image of the eye can be acquired, and accurate gaze information can be obtained. Furthermore, since the photodetector provided in the pixel is used as a sensor for gaze detection, the number of components constituting the electronic device can be reduced, enabling miniaturization and cost reduction of the electronic device.

[0042] Furthermore, one embodiment of the present invention, a reflective and refractive optical system, has a configuration in which multiple elements (optical components) are combined. When this configuration is housed in a housing, it is simply called a lens. Alternatively, due to its thin shape, it is sometimes called a pancake lens.

[0043] Figure 1 is a conceptual diagram illustrating the optical path between an element of an electronic device according to one aspect of the present invention and the eyeball. The electronic device is mainly used for VR applications and comprises a display panel 20, a reflective / refracting optical system 30, and a light source 80. In Figure 1, these are shown in a simplified cross-sectional view.

[0044] The display panel 20 is positioned so that its display surface intersects perpendicularly with the optical axis 57 of the reflecting / refracting optical system 30. In this specification, "perpendicular" means a state in which two straight lines form an angle of 85° to 95°. Here, one of the two straight lines refers to the optical axis 57 of the reflecting / refracting optical system 30, and the other refers to a straight line parallel to the display surface.

[0045] The user can view the image displayed on the display panel 20 by bringing their eye 40 close to the vicinity of the reflective / refracting optical system 30. Because the user views the image with a widened field of view provided by the reflective / refracting optical system 30, they can experience a sense of immersion and presence.

[0046] The display panel 20 has pixels 21 in its display section, and each pixel 21 has a sub-pixel 22 having a light-emitting element and a sub-pixel 23 having a light-receiving element. The light-emitting element is used for display, and the light-receiving element is used to acquire an image of the eye 40 for gaze detection. The reflective / refractive optical system 30 has a linear polarizer 31, a phase difference plate 32, a half mirror 34, a phase difference plate 35, and a reflective polarizer 36. Note that in Figure 1, elements that change the direction of light propagation, such as concave surfaces and lenses, are omitted. Details of these will be described later.

[0047] The sub-pixel 22, which has a light-emitting element, emits visible light (VL: solid arrow) to form an image that can be recognized by humans. The visible light emitted from the sub-pixel 22 is repeatedly reflected and refracted within the reflecting and refraction optical system 30, changing its polarization state, and can be formed as an image on the retina 41 of the human eye.

[0048] In this specification, visible light refers to, for example, light with a wavelength range of 360 nm to 830 nm, or light with a wavelength range from blue light to red light emitted by a display panel (for example, 450 nm to 780 nm).

[0049] In order to image the eye 40 with a sub-pixel 23 having a light-receiving element through the optical action of a lens or the like, the light emitted from the surface of the eye 40 (for example, the pupil 42) must be imaged by the sub-pixel 23. However, when using sub-pixels 22 and 23, which are adjacent to each other and formed on the same plane within the pixel 21, as the starting point, the distance between the surface of the eye 40 and the retina 41 is different. Therefore, with an optical path equivalent to that between sub-pixel 22 and the retina 41, it is not possible to image the light emitted from the surface of the eye 40 with the sub-pixel 23.

[0050] Therefore, in the space between the surface of the eye 40 and the sub-pixel 23, infrared light (IR: dashed arrow) is used as the light emitted from the surface of the eye 40 (reflected light from the light source 80 onto the surface of the eye 40), and the infrared light is incident on the sub-pixel 23 with a different optical path than that between the sub-pixel 22 and the retina 41.

[0051] In order to obtain the clearest possible image by irradiating the sub-pixels 23 with infrared light, it is preferable to configure the reflective / refractive optical system 30 so that infrared light does not interfere, that is, so that infrared light is transmitted, and to limit the light rays incident on the sub-pixels 23, similar to the principle of a pinhole camera that does not use lenses.

[0052] Here, "transmission" does not necessarily mean that the majority of the incident light passes through the element in question. Even if the reflection or absorption of incident light by the element is relatively large, if the transmitted light is used, it may still be described as "transmission."

[0053] Specifically, as shown in Figure 1, the reflecting and refraction optical system 30 uses a half-mirror 34 that transmits infrared light (IR) and semi-transmits and semi-reflects visible light (VL). In addition, a reflective polarizing plate 36 is used that has the function of reflecting polarization a in visible light, transmitting polarization b whose polarization plane is orthogonal to polarization a, and also transmits infrared light.

[0054] Furthermore, a filter 24 is provided on the pixels 21 of the display panel 20, having a shielding layer 24a that transmits visible light (VL) and blocks infrared light (IR). The filter 24 can also be considered an element of the display panel.

[0055] Figure 2 is a top view of pixel 21, showing an example of the layout of sub-pixels 22 and 23. Pixel 21 includes, for example, sub-pixels 22R, 22G, and 22B, each having a light-emitting element of a different emission color, and sub-pixel 23, which has a light-receiving element. The shielding layer 24a is arranged to have an area overlapping with sub-pixels 22R, 22G, and 22B, and the opening 24b is arranged to have an area overlapping with sub-pixel 23.

[0056] Although Figure 2 shows an example where the shape of the opening 24b in a top view is a roughly quadrilateral with curvature at the corners, the shape of the opening 24b is not limited to this. For example, it can be circular, elliptical, roughly circular with multiple curvatures, polygonal, or roughly polygonal with sides having curvature.

[0057] With this configuration, visible light (VL) emitted by the sub-pixel 22 can pass through the filter 24 and enter the reflecting / refracting optical system 30. In addition, infrared light (IR) emitted by the light source 80 and reflected by the eye 40 can pass through the reflecting / refracting optical system 30 and enter the sub-pixel 23. As will be described in detail later, the infrared light emitted by the light source 80 enters the reflecting / refracting optical system 30 in an unpolarized state, but since the linear polarizer 31 transmits only light of a specific polarization plane, the light that enters the sub-pixel 23 becomes polarized.

[0058] Furthermore, a shielding layer that blocks visible light (VL) and infrared light (IR) can also be used as the filter 24. In this case, an opening is also provided in the area overlapping with the sub-pixel 22. However, since the oblique light emitted by the sub-pixel 22 is blocked, it is difficult to improve the viewing angle. The shielding layer 24a that transmits visible light (VL) as described above also transmits the oblique light emitted by the sub-pixel 22, which is advantageous for improving the viewing angle.

[0059] Next, the specific configuration of the reflecting and refraction optical system 30 will be explained using Figures 3A and 3B.

[0060] Figures 3A and 3B show a display panel 20 and a reflector / refractor optical system 30 of an electronic device. Figure 3A also shows the optical path of visible light emitted by a sub-pixel 22 and reaching the eye 40. Figure 3B shows the optical path of infrared light emitted by a light source 80 and reaching the sub-pixel 23. Note that the shapes and arrangements of the elements shown in Figures 3A and 3B are examples only.

[0061] The reflective and refractive optical system 30 has a configuration in which a linear polarizer 31, a phase difference plate 32, a half mirror 34, a phase difference plate 35, a reflective polarizer 36, and a lens 51 are arranged in this order in one direction from the display panel 20 side, and the optical axis 57 is provided to pass through the center of each. The combination of polarizers and phase difference plates (linear polarizer 31 and phase difference plate 32, phase difference plate 35 and reflective polarizer 36) is also called a circular polarizer that converts unpolarized light into circularly polarized light.

[0062] Note that while Figures 3A and 3B show an example where the lens 51 is located between the reflective polarizer 36 and the eye 40, the design is not limited to this. The lens 51 may be located in other positions, or multiple lenses, including lens 51, may be provided. Furthermore, the lens 51, etc., may be used as a support for other elements of the reflective refractive optical system 30 described above. By using a lens as a support, the number of components in the optical system can be reduced.

[0063] Furthermore, in Figures 3A and 3B, the elements constituting the reflecting and refractionating optical system 30 are shown spaced apart to clarify the explanation of the optical path and polarization state, but this is not the only option. Several adjacent elements may be placed in close proximity to each other.

[0064] To create a configuration where adjacent elements are in close proximity, for example, optical contact can be used to arrange two elements in contact without the need for adhesive between them. This reduces the amount of adhesive used and improves heat and chemical resistance. Furthermore, by reducing the number of elements with different refractive indices, unwanted reflections can be prevented.

[0065] Alternatively, it is preferable to bond the elements together using an optical adhesive that has high transmittance with respect to the wavelength of light used (in one embodiment of the present invention, the wavelength range of visible light to infrared light) and does not absorb or birefringe specific polarizations. This reduces the amount of adhesive used and improves heat resistance and chemical resistance. Furthermore, by reducing the number of elements with different refractive indices, unwanted reflections can be prevented.

[0066] Alternatively, instead of bonding, one element can be formed by attaching it to the other using a coating or other method. Alternatively, a gap can be created between the two elements. This configuration allows for changes in the position of the elements along the optical axis, thus increasing design flexibility.

[0067] Furthermore, an anti-reflective layer may be provided on the surface of a light-transmitting element that has an interface with air. By preventing unwanted reflections at the surface of the element (the interface between the air and the element), the efficiency of light utilization can be improved and the generation of stray light can be suppressed. Note that an anti-reflective layer is not necessary for half mirrors and reflective polarizers, which also have a reflective function.

[0068] As the anti-reflective layer, a film-type anti-reflective coating or a dielectric multilayer coating can be used. For example, on curved surfaces such as the surface of a lens where it is not easy to attach a film, it is preferable to provide a dielectric multilayer coating. Also, in the case of an element with a flat surface, either a film-type anti-reflective coating or a dielectric multilayer coating may be provided. However, if the element on which the anti-reflective layer is formed is in the form of a resin film, the element may suffer thermal damage during the formation of the dielectric multilayer coating. In such cases, it is preferable to provide a film-type anti-reflective coating on the element via an adhesive.

[0069] Furthermore, there are two types of anti-reflective films: one that cancels out reflected light through interference, and a moth-eye type that continuously changes the refractive index due to fine protrusions formed on the surface. In either type, it is preferable to use a base film that is not manufactured by the stretching method. Films manufactured using the stretching method may have optical anisotropy, which may change the polarization state. From the perspective of low angle dependence and wavelength dependence, it can be said that it is preferable to use the moth-eye type.

[0070] By using a reflective / refracting optical system 30 with this configuration, the light emitted from the display panel 20 can be converted into linearly polarized or circularly polarized light for use, allowing for selective reflection and transmission by elements arranged along the optical path. Therefore, the optical path length can be secured within a limited space, and the reflective / refracting optical system 30 can be made more compact.

[0071] Next, we will describe the details of each element of the display panel 20 and the reflecting / refracting optical system 30.

[0072] As the display panel 20, 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 easy to form a high-definition display area. In this specification, a microLED refers to a chip with a chip area of ​​10,000 μm². ２ The following light-emitting diodes are represented. Note that the LED panel is not limited to microLEDs, but for example, a chip with a chip area of ​​10,000 μm². ２ Larger than 1 mm ２ The following light-emitting diodes (also called mini-LEDs) may be used. In this embodiment, an example using an organic EL panel will be described.

[0073] The organic EL panel has pixels 21 having sub-pixels 22 and sub-pixels 23. Sub-pixels 22 have light-emitting elements, and sub-pixels 23 have light-receiving elements. As described above, a filter 24 having a shielding layer 24a and an aperture 24b is provided on the pixels. The aperture 24b also has a region that overlaps with the sub-pixels 23.

[0074] Here, the shielding layer 24a has the function of transmitting visible light and shielding infrared light. For such a shielding layer 24a, for example, a dielectric multilayer film, or a translucent resin layer or film containing a material that absorbs infrared light can be used.

[0075] Figure 4A shows the simulation results of the spectral transmittance when light is incident from the air side for a glass / dielectric multilayer film (shielding layer 24a) / air model. Essential Macleod (manufactured by Thin Film Center Inc.) was used as the simulation software.

[0076] For the dielectric multilayer film, a model was used in which thin films with different refractive indices are stacked sequentially from the glass substrate side, as shown in Table 1. The layer with the larger layer number is the interface side with the glass substrate. For low refractive index materials, for example, silicon oxide, magnesium fluoride, lithium fluoride, or sodium fluoride can be used. For high refractive index materials, for example, titanium oxide, silicon nitride, aluminum oxide, zirconium oxide, or hafnium oxide can be used. In the simulation, silicon oxide (SiO₂) was used. ２ ) and titanium dioxide (TiO ２ This envisions a dielectric multilayer film using a laminated film of the following materials.

[0077]

[0078] As shown in Figure 4A, it can be seen that by forming the shielding layer 24a with the configuration shown in Table 1, visible light can be transmitted and infrared light can be blocked.

[0079] The linear polarizer 31 can transmit one linearly polarized light from light (unpolarized) that vibrates in all 360° directions. As the linear polarizer 31, for example, a thin film with iodine or dye uniaxially oriented, a wire grid polarizer, or a dielectric multilayer film can be used.

[0080] In this explanation, the transmission axis of the linear polarizer 31 is assumed to be 0°, but 0° is not an absolute value, but rather a reference value. In other words, the polarization plane of linearly polarized light transmitted through the linear polarizer 31 is treated as 0°. Therefore, for example, 90° linear polarization in this embodiment means linearly polarized light whose polarization plane is rotated by 90° when transmitted through the linear polarizer 31.

[0081] The phase difference plate 32 has the function of converting linearly polarized light into circularly polarized light. Here, a λ / 4 plate (quarter-wave plate) is used for the phase difference plate 32. When the linear polarizer 31 and the λ / 4 plate are superimposed so that the lagging axis of the λ / 4 plate is 45° with respect to the axis of linearly polarized light emitted from the linear polarizer 31, right-rotating circularly polarized light (right circularly polarized light) is produced. Conversely, when the linear polarizer 31 and the λ / 4 plate are superimposed so that the lagging axis of the λ / 4 plate is -45° with respect to the axis of linearly polarized light emitted from the linear polarizer 31, left-rotating circularly polarized light (left circularly polarized light) is produced. In one embodiment of the present invention, either right-rotating or left-rotating circularly polarized light may be used, provided that the combination with the characteristics of the reflective polarizer 36, which will be described later, is appropriate.

[0082] For example, a dielectric multilayer film can be used for the half mirror 34. Here, the half mirror 34 can be a dielectric multilayer film that transmits infrared light and semi-transmits and semi-reflects visible light.

[0083] Figure 4B shows the simulation results of spectral transmittance and spectral reflectance when light is incident from the air side for a glass / dielectric multilayer film (half mirror 34) / air model. As shown in Table 2, a model was used in which thin films with different refractive indices are stacked sequentially from the glass substrate side. The layer with the larger layer number is the interface side with the glass substrate. The same material as the shielding layer 24a described above can be used as the material for the dielectric multilayer film that transmits infrared light and semi-transmits / semi-reflects visible light.

[0084]

[0085] As shown in Figure 4B, a half-mirror 34 that transmits infrared light and semi-transmits and semi-reflects visible light can be formed with the configuration shown in Table 2. Note that, as shown in the visible light region of Figure 4B, semi-transmittance and semi-reflection are not limited to 50% values, but can be in the range of approximately 45% to 55%.

[0086] Furthermore, a dielectric multilayer film using similar materials can be used to form an anti-reflective (AR) layer corresponding to wavelengths ranging from visible light to infrared light.

[0087] As shown in Table 2, the half-mirror 34 is an extremely thin dielectric multilayer film, and therefore requires a support for its formation. In Figures 3A and 3B, the support is omitted, but the material of the support is preferably a material with high transmittance of visible light and infrared light, and can be glass or resin.

[0088] Furthermore, the presence of a curved support surface allows for curvature of the half-mirror 34. For example, as shown in Figure 5A, a plano-convex lens-shaped support 52 having a concave surface in the direction of the eye 40 can be used.

[0089] Here, we will also describe the supports for the other elements shown in Figures 3A and 3B. As a support for the linear polarizer 31 and phase difference plate 32 that act as circular polarizers, for example, as shown in Figure 5A, a display panel 20 can be used, and the linear polarizer 31 and phase difference plate 32 can be bonded to the display surface side.

[0090] Furthermore, as a support for the phase difference plate 35 and the reflective polarizer 36, which act as circular polarizers, a lens 51 can be used, for example, as shown in Figure 5A, and the phase difference plate 35 and the reflective polarizer 36 can be bonded to the visible light (VL) incident side of the lens 51.

[0091] The form of each support is not limited to those described above. For example, as shown in Figure 5B, the phase difference plate 35 and the reflective polarizing plate 36 can be sandwiched between the support 52 and the lens 51. Alternatively, as shown in Figure 5C, the half mirror 34 can be sandwiched between a plano-convex lens-shaped support 52 and a plano-concave lens-shaped support 53, and the phase difference plate 32 and the linear polarizing plate 31 can be bonded to the plane of the support 53 opposite to the concave surface.

[0092] Furthermore, the forms of the support 53 and the lens 51 are not limited to those described above. For example, the support 53 can be a meniscus lens or a biconcave lens, as shown in Figures 5D and 5E. The lens 51 can be a flat plate or a plano-convex lens, as shown in Figures 5F and 5G.

[0093] The focal length of the reflecting / refracting optical system 30 can be determined by the combined effect of the power of the half-mirror 34 acting as a concave mirror and the power of the lenses provided in the reflecting / refracting optical system 30. Therefore, it is preferable to appropriately adjust the shapes of the lens 51, the lens-shaped support 52, and the lens-shaped support 53 so that a desired focal length can be obtained. Furthermore, combinations of multiple supports with different shapes have the following characteristics and can be appropriately selected according to the purpose.

[0094] The Petzval sum, calculated from the refractive index and focal length of each lens, serves as an indicator of field curvature. When the Petzval sum is zero, the image plane becomes flat, which is a desirable characteristic for the lens system. To satisfy this, either the refractive index or the focal length must be negative. Since the refractive index cannot be negative, it is preferable to use a concave lens with a negative focal length. Therefore, to suppress field curvature, it is preferable that one or more of the lens 51, support 52, and support 53 have a concave lens shape.

[0095] Since refraction is accompanied by chromatic aberration, combining positive and negative power is effective in correcting chromatic aberration. Even if the incident surface is flat, chromatic aberration will occur unless the light rays are parallel. Therefore, a combination of surfaces that can correct each other (convex and concave surfaces) is advantageous. Accordingly, to suppress chromatic aberration, it is preferable that the combination of lens 51, support 52, and support 53 be a combination of a convex lens shape and a concave lens shape.

[0096] Simply put, the greater the positive power, the shorter the focal length can be, and the smaller the overall optical system can be. Even in a configuration where most of the positive power is handled by a half-mirror, the presence of a convex surface allows for an even shorter focal length. Therefore, in order to increase the positive power as much as possible, it is preferable that one or more of the lens 51, support 52, and support 53 have the shape of a convex lens.

[0097] In a reflective / refractive optical system as described in one aspect of the present invention, polarizers and phase difference plates are required. These are in the form of films, and a flat bonding surface is advantageous from a manufacturing perspective. Therefore, from the viewpoint of ease of manufacturing, it is preferable that one or more of the lens 51, support 52, and support 53 have a flat surface on the outside.

[0098] The above is just one example of the characteristics of the support shape when mainly considering the visible light that forms the image, but in one embodiment of the present invention, the transmission of infrared light also needs to be considered.

[0099] As mentioned above, most of the light incident on the surface of the filter 24 from an oblique direction cannot pass through the aperture 24b, while light incident on the surface of the filter 24 from a perpendicular direction can easily pass through the aperture 24b. Therefore, if there is a large refraction in the reflecting / refracting optical system 30, the amount of light transmitted through the aperture 24b may decrease. Conversely, if a large amount of light is transmitted through the aperture 24b due to refraction, the acquired image is more likely to be distorted, and correction may be necessary.

[0100] Therefore, when considering only infrared light, it is preferable that the power of the elements involved in infrared light in the reflecting / refracting optical system 30 is as close to zero as possible. Based on the above, it can be said that the form of the support that the reflecting / refracting optical system 30 has and that acts as a lens is preferably the shape of a meniscus lens with the lowest possible power.

[0101] The phase difference plate 35 has the function of reversibly converting linearly polarized and circularly polarized light. Similar to the phase difference plate 32, a λ / 4 plate (quarter-wave plate) can be used as the phase difference plate 35.

[0102] The reflective polarizer 36 can reflect linearly polarized light whose reflection axis and vibration direction coincide, and transmit linearly polarized light perpendicular to the reflection axis. The axis perpendicular to the reflection axis is called the transmission axis. The reflective polarizer 36 is positioned so that its transmission axis is perpendicular to and overlaps with the transmission axis of the linear polarizer 31. This arrangement allows for the creation of an optical path for visible light accompanied by reflection.

[0103] In one embodiment of the present invention, the reflective polarizing plate 36 needs to transmit infrared light. As such a reflective polarizing plate, for example, a dielectric multilayer film made by laminating at least two types of birefringent polymer materials can be used.

[0104] The lens 51 can take on various forms, taking into consideration its combination with the other supports mentioned above. For example, the lens 51 can be a combination of one or more lenses selected from biconvex lenses, plano-convex lenses, convex meniscus lenses, biconcave lenses, plano-concave lenses, and concave meniscus lenses. Furthermore, the lens 51 is not limited to spherical lenses, but may also be an aspherical lens. By using a combination lens or an aspherical lens, various lens aberrations can be reduced.

[0105] For the lenses used in the reflecting / refracting optical system 30, it is desirable to use resin lenses to reduce weight. On the other hand, resins have a tendency to exhibit birefringence. In materials with birefringence, the refractive index differs depending on the direction of polarization vibration, so the transmission speed differs for each polarization component. Therefore, after passing through the material, a phase difference occurs between the polarization components, causing a change in the polarization state. In a reflecting / refracting optical system, when a change in the polarization state occurs, light rays that do not pass through the normal optical path are generated. These light rays enter the eye as stray light and are perceived as a double image or a blurred image.

[0106] The relationship between polarization state and optical path will be described later, but for the reasons mentioned above, it is preferable that lenses located in the optical path through which polarized light travels back and forth be made of glass, which exhibits almost no birefringence. Furthermore, since humans cannot perceive polarization, even if a resin lens with birefringence is used in the lens positioned directly in front of the eye 40, there will be no problem in the visibility of the display.

[0107] For example, acrylic resin, polycarbonate resin, polyester resin, and cycloolefin resin are known to be used as resins for lenses, and these can typically be used as lens materials. Furthermore, if a material with sufficiently low birefringence is used, resin lenses can also be used in the optical path on which polarized light travels back and forth.

[0108] Next, we will explain the optical path of the visible light emitted by the sub-pixel 22 shown in Figure 3A.

[0109] Some of the light emitted from the sub-pixels 22 of the display panel 20 passes through the filter 24, the linear polarizer 31, and the phase difference plate 32, partially passes through the half mirror 34, passes through the phase difference plate 35, and is reflected by the reflective polarizer 36. The light reflected by the reflective polarizer 36 passes through the phase difference plate 35 and is partially reflected by the half mirror 34. The light partially reflected by the half mirror 34 passes through the phase difference plate 35, the reflective polarizer 36, and the lens 51, enters the eye 40, and forms an image on the retina 41.

[0110] In this way, by repeatedly reflecting within the reflective / refracting optical system 30, the optical path length can be secured, making it possible to create an optical system with a short focal length.

[0111] The details of the optical path, including the polarization state, will now be explained. Light (unpolarized) vibrating in all 360° directions emitted from the display panel 20 is incident on the linear polarizer 31. The transmission axis of the linear polarizer 31 is 0°, and 0° linearly polarized light is emitted from the linear polarizer 31. If a liquid crystal panel is used for the display panel 20, the linear polarizer 31 can be used as one of the pair of polarizers that the liquid crystal panel has.

[0112] The 0° linearly polarized light emitted from the linear polarizer 31 is converted to left-circularly polarized light (L) by the phase difference plate 32. The left-circularly polarized light (L) is partially transmitted through the half mirror 34 and incident on the phase difference plate 35, where it is converted back to 0° linearly polarized light. Here, we describe an example where the light emitted from the phase difference plate 32 is left-circularly polarized, but it can also be right-circularly polarized.

[0113] The 0° linearly polarized light emitted from the phase difference plate 35 is reflected by the reflective polarizer 36 with a reflection axis of 0°, incident on the phase difference plate 35, and converted to left circularly polarized light (L). The left circularly polarized light (L) is partially reflected by the half mirror 34, and its polarity is reversed to right circularly polarized light (R). The right circularly polarized light (R) is incident on the phase difference plate 35 and converted to 90° linearly polarized light. The 90° linearly polarized light passes through the reflective polarizer 36 and lens 51 with a transmission axis of 90° and is incident on the eye 40.

[0114] Next, we will explain the optical path of infrared light emitted from the surface of the eye 40 shown in Figure 3B.

[0115] Infrared light (IR) emitted from the light source 80 travels toward the eye 40 and reaches the eye 40 or its vicinity. A portion of the infrared light (IR) is reflected by the eye 40 or its vicinity and travels toward the reflectivity optical system 30, reaching the sub-pixel 23. In this way, the infrared light (IR) emitted by the light source 80 and reflected by the eye 40 or its vicinity can be detected by the sub-pixel 23, which has a photodetector, and by periodically acquiring an image of the eye 40, dynamic information of the eye 40 can be obtained.

[0116] Furthermore, by acquiring images of the vicinity of the eye 40, it is possible to detect the number of blinks per unit time and the blinking speed. The number and speed of blinks are said to be related to fatigue levels, and it is also possible to detect fatigue levels by detecting information related to blinking.

[0117] Furthermore, it is preferable to use near-infrared light (for example, light with a wavelength of 780 nm to 2 μm) with relatively high energy, as the light emitted by the light source 80 is infrared light with low visual sensitivity that has little impact on visibility, and is easily converted into photoelectric form by the photodetector.

[0118] Furthermore, it is preferable that the infrared light (IR) irradiated from the light source 80 to the eye 40 be unpolarized. As mentioned above, since the reflective polarizer 36 and the half mirror 34 have the function of transmitting infrared light (IR), the unpolarized infrared light is not attenuated ideally until it reaches the linear polarizer 31.

[0119] Thus, because the transmittance of infrared light in the reflecting / refracting optical system 30 is relatively high, there is no need to irradiate the human body (eye 40) with strong infrared light, and the intensity of the light reaching the sub-pixels 23 can be increased, making it easier to acquire clear images.

[0120] A portion of the light emitted from the light source 80 and reflected from the surface of the eye 40 passes through the lens 51, reflective polarizer 36, phase difference plate 35, half mirror 34, and phase difference plate 32, and is incident on the linear polarizer 31. Here, since the transmission axis of the linear polarizer 31 is 0°, polarization components with a polarization plane of 0° are transmitted.

[0121] Figure 6 shows a portion of the light rays emitted from the linear polarizing plate 31 that reach the display panel 20. Of the light emitted from the linear polarizing plate 31, the rays that enter the shielding layer 24a of the filter 24 of the display panel 20 are absorbed or reflected, and the rays that proceed to the aperture 24b enter the sub-pixels 23.

[0122] Here, the majority of the light incident on the shielding layer 24a is the superposition of light emitted from the eye 40 and all points in its vicinity, whereas the light that travels to the aperture 24b is light emitted from the eye 40 and a limited number of points in its vicinity. The former is the superposition of information from many points in the eye 40 and its vicinity, while the latter is the information from only a few points.

[0123] In other words, since information from a limited number of points is stored in one sub-pixel 23 (light-receiving element), each of the multiple sub-pixels 23 (light-receiving elements) will store information from points at different positions in and around the eye 40. Therefore, based on the same principle as a pinhole camera, blurring is less likely to occur, and a reasonably clear image can be obtained. However, in reality, the aperture 24b is not a point but has size, so light rays from multiple points enter. For this reason, it is preferable to determine the size of the aperture 24b so that the desired image can be obtained.

[0124] In the above description, the aperture 24b of the filter 24 is paired with the sub-pixel 23, but this is not the only configuration. For example, as shown in Figures 7A to 7D, a filter 24 having a geometric mask pattern can also be used.

[0125] In this configuration, a mask pattern on which a decoding function can be set is used. An image obtained by infrared light transmitted through the mask pattern and incident on the sub-pixel 23 is acquired, A / D conversion is performed, and the image is decoded by a computer to obtain the desired image. By combining decoding with inference using artificial intelligence, a clearer image can be obtained.

[0126] Examples of mask patterns that can be used as a filter 24 include a configuration in which shielding layers 24a and openings 24b are arranged alternately in concentric circles (see Figure 7B), a configuration in which shielding layers 24a and openings 24b are arranged alternately in a radial pattern (see Figure 7C), a configuration in which shielding layers 24a and openings 24b are arranged randomly, or a configuration in which multiple such randomly arranged configurations are arranged regularly (see Figure 7D).

[0127] In the above description, the filter 24 is an element of the display panel 20 and is located between the pixel 21 and the reflective / refracting optical system 30. However, the position of the filter 24 is not limited to this. For example, as shown in Figure 7E, the reflective / refracting optical system 30 can be sandwiched between the filter 24 and the display surface of the display panel 20. In this case, the reflective / refracting optical system 30 can have the same configuration as shown in Figure 3A, etc., but the shielding layer 24a of the filter 24 has only one opening 24b.

[0128] For example, it is preferable to provide an aperture 24b that coincides with the optical axis 57 of the reflecting / refracting optical system 30. This aperture 24b limits the light rays emitted from the eye 40 and its vicinity, so that an image of the eye 40 and its vicinity can be acquired by infrared light (IR) that passes through the reflecting / refracting optical system 30 and reaches the sub-pixel 23, using the same principle as a pinhole camera. To obtain a clear image that is not problematic in practice, it is preferable to set the diameter of the aperture 24b to 0.1 mm to 1.0 mm. The filter 24 can be provided, for example, in contact with the infrared light (IR) incident side of the lens 51 shown in Figures 5A, 5B, 5C, 5F, (G).

[0129] Figure 8A is a diagram illustrating a display panel 20 of an electronic device according to one embodiment of the present invention. The display panel 20 has a pixel array 14, and circuits 15, 16, 17, 18, and 19. The pixel array 14 has pixels 21 arranged in the column direction and row direction.

[0130] Pixel 21 may have sub-pixels 22 and 23. For example, sub-pixel 22 has the function of emitting display light. Sub-pixel 23 has the function of detecting light irradiated onto the display panel 20.

[0131] 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."

[0132] The sub-pixel 22 has a light-emitting element 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 element. 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). In addition, LEDs such as microLEDs (Light Emitting Diodes) can also be used as the light-emitting element.

[0133] The sub-pixel 23 has a photodetector that is sensitive to infrared light. For example, near-infrared light can be used as the infrared light. The photodetector can be a photoelectric conversion element that detects incident light and generates an electric charge. In the photodetector, the amount of charge generated is determined based on the amount of incident light. For example, a pn-type or PIN-type photodiode can be used as the photodetector.

[0134] As the light-receiving element, it is preferable to use an organic photodiode having an organic compound in its photoelectric conversion layer. Organic photodiodes are easy to make thin, light, and large in area. Also, because they offer a high degree of freedom in shape and design, they can be applied to various display panels. Alternatively, a photodiode using crystalline silicon (such as single-crystal silicon, polycrystalline silicon, or microcrystalline silicon) can also be used as the light-receiving element.

[0135] In one aspect of the present invention, an organic EL element is used as the light-emitting element, and an organic photodiode is used as the light-receiving element. The organic photodiode may have a configuration that shares elements with the organic EL element. Therefore, the light-receiving element can be incorporated into the display panel 20 without significantly increasing the manufacturing process. For example, the photoelectric conversion layer of the light-receiving element and the light-emitting layer of the light-emitting element may be manufactured separately, while the other layers may include the same configuration for both the light-emitting element and the light-receiving element.

[0136] Circuits 15 and 16 are driver circuits for driving the sub-pixels 22. Circuit 15 can function as a source driver, and circuit 16 can function as a gate driver. Circuits 15 and 16 can use, for example, shift register circuits. Note that the driving circuits for sub-pixels 22 and 23 may be separated.

[0137] Circuits 17 and 18 are driver circuits for driving the sub-pixels 23. Circuit 17 can function as a column driver, and circuit 18 can function as a row driver. Circuits 17 and 18 can be, for example, shift register circuits or decoder circuits.

[0138] Circuit 19 is a data readout circuit for the data output by the sub-pixel 23. Circuit 19 may include, for example, an A / D conversion circuit that converts the analog data output from the sub-pixel 23 into digital data. Circuit 19 may also include a CDS circuit that performs correlated double sampling on the output data.

[0139] As shown in Figure 8B, circuits 15 to 19 may be configured to overlap with the pixel array 14. This configuration allows for the formation of a narrow-bezel display panel. Furthermore, by having the drive circuits located below the pixel array 14, wiring length and wiring capacitance can be reduced. Therefore, a display panel that can operate at high speed and with low power consumption can be achieved. Note that the arrangement and area of ​​circuits 15 to 19 shown in Figure 8B are just an example and can be changed as appropriate. In addition, some of circuits 15 to 19 can be formed on the same layer as the pixel array 14.

[0140] In this configuration, for example, circuits 15 to 19 can be formed using transistors (hereinafter referred to as Si transistors) fabricated on a single-crystal silicon substrate, and the pixel circuits of the pixel array 14 can be formed using transistors (hereinafter referred to as OS transistors) having a metal oxide in the channel formation region. OS transistors can be formed as thin films and can be formed by stacking them on top of Si transistors.

[0141] The sub-pixel 23 has a light-receiving element that can be used to acquire imaging data such as eye movements or changes in pupil diameter. By analyzing this image data, gaze detection can be performed. By detecting gaze, it can function as an input interface. Alternatively, foveal rendering can be applied. Furthermore, the light-receiving element can be used to acquire imaging data such as the iris. In other words, a biometric authentication function can be added to the display panel.

[0142] Figures 8C to 8E illustrate examples of sub-pixel layouts within a pixel 21. Figure 8A shows an example where one sub-pixel 22 and one sub-pixel 23 are placed within a pixel 21. However, as shown in Figure 8C, a sub-pixel 22R having a red light-emitting element, a sub-pixel 22G having a green light-emitting element, and a sub-pixel 22B having a blue light-emitting element may also be placed within the pixel 21. This configuration enables color display.

[0143] Note that while Figure 8C shows a layout in which sub-pixels 22R, 22G, 22B, and 23 are arranged vertically and horizontally, the layout shown in Figure 8D may also be used.

[0144] Furthermore, as shown in Figure 8E, a sub-pixel 22W having a light-emitting element that emits white light may be provided. Since the sub-pixel 22W can emit white light on its own, the luminescence of sub-pixels of other colors can be suppressed when displaying white or a color close to white. Therefore, display can be performed with low power consumption.

[0145] Note that the arrangement of the subpixels shown in Figures 8C to 8E may be rearranged. Furthermore, the configuration of pixels and subpixels is not limited to those described above, and various arrangements can be adopted.

[0146] For example, as shown in Figures 9A and 9B, a pixel 21a having sub-pixels 22 (sub-pixels 22R, 22G, 22B) and a pixel 21b having sub-pixels 22 (sub-pixels 22R, 22G, or 22B) and sub-pixel 23 may be created separately.

[0147] When pixels 21a and 21b are created in this manner, they may be arranged alternately as shown in Figure 9C. Alternatively, one pixel 21b may be placed for every multiple pixels 21a. Since the subpixels 22 constitute an image, it is preferable to arrange them at a high density, but when acquiring the position information of the eye 40, a resolution higher than necessary is not required. Therefore, the number of pixels 21b having subpixels 23 can be less than the number of pixels 21a.

[0148] Alternatively, as shown in Figure 9D, pixels 21a may be placed in region 25 near the center of the pixel array 14, and pixels 21b may be placed in region 26 outside region 25. Region 26 is often outside the central field of vision, where the resolution of the human eye is relatively low, so even if the resolution is reduced, it is difficult for people to recognize. On the other hand, region 25 is often at the center of the field of vision, where the resolution of the human eye is high. Therefore, it is preferable to provide region 25 near the center of the pixel array 14 and display it at high resolution.

[0149] Next, we will describe examples of pixel circuits for sub-pixels having light-emitting elements and pixel circuits for sub-pixels having light-receiving elements.

[0150] Figure 10A shows an example of a pixel circuit PIX1 applicable to a sub-pixel 22. A similar circuit can also be used for the light source 80. The pixel circuit PIX1 includes a light-emitting element EL1, transistors M1, M2, M3, and capacitor C1. Here, an example using a light-emitting diode as the light-emitting element EL1 is shown. It is preferable to use an organic EL element that emits visible light for the light-emitting element EL1.

[0151] Transistor M1 has its gate connected to wiring G1, one of its source or drain connected to wiring S1, and the other of its source or drain connected to one electrode of capacitor C1 and the gate of transistor M2. One of the source or drain of transistor M2 is connected to wiring V2, and the other is connected to the other electrode of capacitor C1, the anode of light-emitting element EL1, and one of the source or drain of transistor M3. Transistor M3 has its gate connected to wiring G2, and the other of its source or drain connected to wiring V0. The cathode of light-emitting element EL1 is connected to wiring V1.

[0152] A constant potential is supplied to wiring V1 and wiring V2, respectively. Light emission can be achieved by setting the anode side of the light-emitting element EL1 to a high potential and the cathode side to a low potential. Transistor M1 is controlled by the signal supplied to wiring G1 and functions as a selection transistor to control the selected state of the pixel circuit PIX1. Transistor M2 functions as a drive transistor that controls the current flowing to the light-emitting element EL1 according to the potential supplied to the gate.

[0153] When transistor M1 is conducting, the potential supplied to wiring S1 is supplied to the gate of transistor M2, and the luminescence brightness of the light-emitting element EL1 can be controlled according to that potential. Transistor M3 is controlled by a signal supplied to wiring G2. This allows the potential between transistor M3 and the light-emitting element EL1 to be reset to a constant potential supplied from wiring V0, and the potential can be written to the gate of transistor M2 while the source potential of transistor M2 is stabilized.

[0154] Figure 10B shows an example of a circuit PIX2 applicable to the sub-pixel 23. Circuit PIX2 includes a photodetector PD1, transistors M4, M5, M6, M7, and capacitor C2. Here, an example is shown in which a photodiode is used as the photodetector PD1.

[0155] The photodetector PD1 has its cathode connected to wiring V1 and its anode connected to either the source or drain of transistor M4. Transistor M4 has its gate connected to wiring G3 and its other source or drain connected to one electrode of capacitor C2, either the source or drain of transistor M5, and the gate of transistor M6. Transistor M5 has its gate connected to wiring G4 and its other source or drain connected to wiring V3. Transistor M6 has one source or drain connected to wiring V4 and its other source or drain connected to either the source or drain of transistor M7. Transistor M7 has its gate connected to wiring G5 and its other source or drain connected to wiring OUT.

[0156] A constant potential is supplied to wiring V1, wiring V3, and wiring V4, respectively. When the photodetector PD1 is driven with reverse bias, a potential lower than the potential of wiring V1 is supplied to wiring V3. Transistor M5 is controlled by a signal supplied to wiring G5 and has the function of resetting the potential of the node connected to the gate of transistor M6 to the potential supplied to wiring V3. Transistor M4 is controlled by a signal supplied to wiring G3 and has the function of controlling the timing at which the potential of the node changes according to the current flowing through the photodetector PD1. Transistor M6 functions as an amplifying transistor that provides an output according to the potential of the node. Transistor M7 is controlled by a signal supplied to wiring G6 and functions as a selection transistor for reading out the output according to the potential of the node with an external circuit connected to wiring OUT.

[0157] Furthermore, as a modified version of circuit PIX2, circuit PIX3 shown in Figure 10C can also be used. Circuit PIX3 differs from circuit PIX2 in that it has a transistor M8 and a capacitor C3. In Figure 10C, elements common to both PIX2 and PIX3 are given the same reference numerals.

[0158] The photodetector PD1 has its cathode connected to wiring V1 and its anode connected to either the source or drain of transistor M4. Transistor M4 has its gate connected to wiring G3 and its other source or drain connected to one electrode of capacitor C3 and one source or drain of transistor M5. Transistor M5 has its gate connected to wiring G4 and its other source or drain connected to wiring V3. The other electrode of capacitor C3 is connected to either the source or drain of transistor M8, one electrode of capacitor C2, and the gate of transistor M6. Transistor M8 has either its source or drain connected to wiring V5 and its gate connected to wiring G6. Transistor M6 has either its source or drain connected to wiring V4 and its other source or drain connected to either the source or drain of transistor M7. Transistor M7 has its gate connected to wiring G5 and its other source or drain connected to wiring OUT.

[0159] Here, node FD1 is defined as the point (wiring, electrode, etc.) connecting the other source or drain of transistor M4, one electrode of capacitor C3, and one source or drain of transistor M5. Also, node FD2 is defined as the point (wiring, electrode, etc.) connecting the other electrode of capacitor C3, one source or drain of transistor M8, one electrode of capacitor C2, and the gate of transistor M6.

[0160] A constant potential is supplied to wirings V1, V3, V4, and V5. When the photodetector PD1 is driven with reverse bias, a potential lower than that of wiring V1 is supplied to wiring V3. Transistor M5 is controlled by a signal supplied to wiring G5 and has the function of resetting node FD1 to the potential supplied to wiring V3. Transistor M8 is controlled by a signal supplied to wiring G6 and has the function of resetting node FD2 to the potential supplied to wiring V5. Transistor M4 is controlled by a signal supplied to wiring G3 and has the function of controlling the timing at which the potential of node FD1 changes according to the current flowing through the photodetector PD1. Transistor M6 functions as an amplifying transistor that outputs according to the potential of node FD2. Transistor M7 is controlled by a signal supplied to wiring G6 and functions as a selection transistor for reading out the output according to the potential of the above nodes with an external circuit connected to wiring OUT.

[0161] PIX3 has nodes FD1 and FD2, which can store electric charge, and these are connected via capacitor C3. Furthermore, reset transistors (transistors M4 and M8) are connected to nodes FD1 and FD2, allowing them to be reset independently. Therefore, the initial state can be stored in node FD2, and the difference between this state and the imaging data stored in node FD1 can be output.

[0162] For example, in the initial state (first imaging), the imaging operation is performed with node FD2 in a reset state, and by making node FD2 floating, the potential of the initial state can be stored.

[0163] Next, only the potential of node FD1 is reset, and the second imaging operation is performed. Since the potential of node FD2 follows the potential change of node FD1 due to the capacitive coupling of capacitor C3, if the potential of node FD1 is the same as the initial state in the second and subsequent imaging operations, the potential of node FD2 will not change, and a difference of 0 (no change) can be read out. Also, if the potential of node FD1 is different from the initial state, the potential of node FD2 will change by the difference from the initial state, and a change can be read out.

[0164] In other words, by using PIX3 as the sub-pixel 23 in one aspect of the present invention, it is possible to read out whether or not there is a change in the eye and its vicinity.

[0165] It is preferable to use transistors having an oxide semiconductor in the channel formation region (hereinafter referred to as OS transistors) for transistors M1 to M8 in the pixel circuits PIX1, PIX2, and PIX3. By using an oxide semiconductor with a large band gap in the semiconductor layer of the transistor, the off-current of the OS transistor can be reduced. The band gap of the oxide semiconductor is preferably 2 eV or more, and more preferably 2.5 eV or more.

[0166] 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 with 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.

[0167] The semiconductor layer provided in the OS transistor preferably contains indium. Alternatively, it is preferable to have indium, M (where M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, it is preferable that M is one or more selected from aluminum, gallium, yttrium, and tin.

[0168] For example, it is preferable to use an indium-containing oxide (InOx) as the semiconductor layer of the OS transistor. Alternatively, it is preferable to use an oxide containing indium and gallium (also written as IGO). Alternatively, it is preferable to use an oxide containing indium, gallium, and zinc (also written as IGZO). Alternatively, it is preferable to use an oxide containing indium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc.

[0169] Furthermore, the oxide semiconductor used for the semiconductor layer of the OS transistor is preferably formed using the sputtering method or the ALD method. When forming the oxide semiconductor using the sputtering method, productivity can be increased and the film density can be increased. When forming the oxide semiconductor using the ALD method, the coverage of the film can be improved.

[0170] OS transistors, which have oxide semiconductors with a wider bandgap and lower carrier concentration than silicon, can achieve extremely low off-currents. Therefore, this low off-current allows the charge stored in a capacitor connected in series with the transistor to be retained for extended periods.

[0171] Therefore, it is preferable to use transistors made of oxide semiconductors, particularly transistors M1, M4, M5, and M8, which have one or both of their sources or drains connected to capacitors C1, C2, or C3.

[0172] Furthermore, the manufacturing cost of other transistors can also be reduced by using transistors that utilize oxide semiconductors in a similar manner.

[0173] Furthermore, transistors M1 to M8 can also be transistors in which silicon is applied as the semiconductor in which the channel is formed. In particular, using highly crystalline silicon such as single-crystal silicon or polycrystalline silicon is preferable because it can achieve high field-effect mobility, enabling faster operation.

[0174] Alternatively, one or more of the transistors M1 to M8 may be made of oxide semiconductor material, while the others may be made of silicon.

[0175] Although Figures 10A to 10C illustrate an example using an n-channel transistor, a p-channel transistor can also be used.

[0176] Figure 11 shows an example of a goggle-type device, which is an electronic device according to one aspect of the present invention. Here, the combination of the display panel 20 and the reflective / refractive optical system 30 is shown as a display unit 70 with a dashed line. The display unit 70 corresponds to the configuration shown in Figures 3A, 3B, etc.

[0177] The user can view the image displayed on the display panel 20 by bringing their eyes close to the vicinity of the reflective / refracting optical system 30 located on the display surface side of the display panel 20. Because the user views the image with a widened field of view provided by the reflective / refracting optical system 30, they can experience a sense of immersion and presence.

[0178] Two sets of display units 70 are incorporated into the housing 71. One display unit 70 is for the right eye, and the other display unit 70 is for the left eye. By displaying images corresponding to the parallax in each display unit 70, the user can perceive a sense of depth in the images.

[0179] The housing 71 and the holder 75 shown in Figure 11 may be provided with input and output terminals on one or both sides. The input terminal can be connected to a cable that supplies video signals from a video output device, power for charging the battery, etc. The output terminal can function as, for example, an audio output terminal, and earphones, headphones, etc. can be connected to it. However, if the system is configured to output audio data via wireless communication, or if audio is output from an external video output device, the audio output terminal does not need to be provided.

[0180] Furthermore, a wireless communication module and a storage module may be provided in one or both of the housing 71 and the holder 75 shown in Figure 11. Wireless communication can be performed using the wireless communication module, and content to be viewed can be downloaded and stored in the storage module. This allows the user to view the downloaded content offline.

[0181] Furthermore, the light-receiving element of the display panel 20 can function as a gaze detection sensor. The gaze detection sensor uses light emitted from a light source 80 provided inside the housing 71 and detects the position of the gaze by reading changes in reflected light due to the movement of the pupil, iris, and white of the eye. For example, it may detect changes in reflectivity caused by actions such as shifting the pupil to one side or up or down, and assign this to the operation of electronic devices.

[0182] For example, operations such as power on, power off, sleep, volume adjustment, channel change, menu display, selection, confirmation, and back, as well as video playback, stop, pause, fast forward, and rewind, can be assigned to the eyelid opening and closing movements and eyeball movements described above. Furthermore, detected gaze information can also be used for foveal rendering.

[0183] Furthermore, the system may detect the user's fatigue level from dynamic changes in blinking and display an alert. Since blinking is strongly related to eye fatigue, the fatigue level can be estimated by detecting the number of blinks, intervals, and eyelid opening and closing speed within a unit of time.

[0184] If blinking behavior that suggests increasing fatigue is detected, the electronic device can take actions such as displaying a message or sound prompting a break, lowering the display brightness, or lowering the display color temperature to address the user's fatigue.

[0185] Furthermore, if a message or audio prompting a break is displayed, the user may feel uncomfortable if their work, entertainment, or immersion is interrupted against their will. Therefore, when prompting a break, it may be acceptable to activate equipment that emits sound, vibration, or odor to guide the user to consciously want to take a break.

[0186] While the above example illustrates detecting fatigue through blinking, fatigue or illness may also be detected by obtaining other information. For example, by comparing the amount of reflected light on the surface of the eyeball with that of a normal eye, changes in the tear film can be detected to suppress dry eye or address dry eye symptoms. Alternatively, the degree of eye opening (eyelid opening) can be detected by the amount of reflected light and compared with that of a normal eye to estimate the degree of fatigue.

[0187] Furthermore, conscious eyelid opening and closing can be used to perform input actions on electronic devices. For example, actions such as blinking with only one eye, blinking a predetermined number of times within a certain period of time, or closing the eyelids for a certain period of time can be assigned to operate electronic devices.

[0188] (Embodiment 2) This embodiment describes an example of the configuration of a display panel according to one aspect of the present invention.

[0189] In the display section of a display panel according to one embodiment of the present invention, it is preferable to use an MML (metal maskless) structure in which the light-emitting layer is separated and formed using a lithography process, rather than using an FMM (fine metal mask). An MML structured light-emitting element can have a higher aperture ratio than a light-emitting element made using an FMM, enabling light emission at high brightness or low power consumption. Furthermore, the light extraction efficiency can be further improved by combining an MML structured light-emitting element with a convex lens.

[0190] [Display Panel 200A] The display panel 200A shown in Figure 12 has a substrate 301, a light-emitting element 110R, a light-receiving element 110PD, capacitors 240a and 240b, and transistors 310a and 310b. The light-emitting element 110R and the light-receiving element 110PD correspond to the light-emitting element of the sub-pixel 22R and the light-receiving element of the sub-pixel 23 shown in Figures 7C to 7E, respectively. The light-emitting element 110R, transistor 310a, and capacitor 240a correspond to, for example, the light-emitting element EL1, transistor M1, and capacitor C1 shown in Figure 10A, respectively. The light-receiving element 110PD, transistor 310b, and capacitor 240b correspond to, for example, the light-receiving element PD1, transistor M4, and capacitor C2 shown in Figure 10B, respectively.

[0191] The transistor 310 (transistors 310a, 310b) is a transistor having a channel formation region in the substrate 301. As the substrate 301, a semiconductor substrate such as a single-crystal silicon substrate can be used. The transistor 310 has a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region 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.

[0192] Furthermore, an element isolation layer 315 is provided between two adjacent transistors so as to be embedded in the substrate 301.

[0193] Furthermore, an insulating layer 261 is provided to cover the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0194] Capacitors 240 (capacitors 240a, 240b) have a conductive layer 241 (conductive layers 241a, 241b), a conductive layer 245 (conductive layers 245a, 245b), and an insulating layer 243 located between them. Conductive layer 241 functions as one electrode of capacitor 240, conductive layer 245 functions as the other electrode of capacitor 240, and insulating layer 243 functions as the dielectric of capacitor 240.

[0195] The conductive layer 241 of capacitance 240 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is connected to either the source or drain of transistor 310a or 310b 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.

[0196] An insulating layer 255a is provided covering the capacitance 240, an insulating layer 255b is provided on top of the insulating layer 255a, and an insulating layer 255c is provided on top of the insulating layer 255b.

[0197] 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.

[0198] A light-emitting element 110R and a light-receiving element 110PD are provided on the insulating layer 255c.

[0199] As the light-emitting element 110R, it is preferable to use, for example, an OLED (Organic Light Emitting Diode) or a QLED (Quantum-dot Light Emitting Diode). As the light-emitting material of the EL element, not only organic compounds but also inorganic compounds (such as quantum dot materials) can be used.

[0200] The light-emitting element 110R includes a pixel electrode 111R, an organic layer 112R, a common layer 114, and a common electrode 113.

[0201] The pixel electrode 111R of the light-emitting element 110R is connected to either the source or drain of the transistor 310a by an insulating layer 255a, an insulating layer 255b, and a plug 256a embedded in the insulating layer 255c and insulating layer 243, a conductive layer 241a embedded in the insulating layer 254, and a plug 271a embedded in the insulating layer 261.

[0202] The organic layer 112R of the light-emitting element 110R contains at least a light-emitting organic compound that emits red light. The organic layer 112R can also be called an EL layer and has a layer (light-emitting layer) containing at least a light-emitting substance.

[0203] The organic layer 112R 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 112R can 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 111R side, and the common layer 114 can have an electron injection layer.

[0204] The common electrode 113 and the common layer 114 are provided as a continuous layer common to the light-emitting element. A conductive film that is transparent to visible light is used on either the pixel electrode or the common electrode 113, and a conductive film that is reflective is used on the other. By making the pixel electrode transparent and the common electrode 113 reflective, a bottom-emission type display panel can be made, and conversely, by making the pixel electrode reflective and the common electrode 113 transparent, a top-emission type display panel can be made. Furthermore, by making both the pixel electrode and the common electrode 113 transparent, a dual-emission type display panel can also be made.

[0205] A protective layer 121 is provided on the common electrode 113, covering the light-emitting element 110R. The protective layer 121 has the function of preventing impurities such as water from diffusing to the light-emitting element from above.

[0206] An insulating layer 124, an insulating layer 125, and a resin layer 126 are provided between adjacent light-emitting elements and light-receiving elements, or between two light-emitting elements.

[0207] The resin layer 126 has a smooth, convex upper surface shape, and the common layer 114 and common electrode 113 are provided covering the upper surface of the resin layer 126.

[0208] The resin layer 126 functions as a planarizing film that fills the step gaps located between adjacent light-emitting elements and light-receiving elements, or between two light-emitting elements. By providing the resin layer 126, it is possible to prevent the common electrode 113 from being separated by the step gap at the edge of the organic layer 112R (also called step breakage), and to prevent the common electrode on the organic layer 112R from becoming insulated.

[0209] Furthermore, the resin layer 126 insulates the organic layers of adjacent light-emitting elements 110R from each other. This reduces the leakage current between adjacent light-emitting elements via the organic layer, thereby suppressing unwanted light emission due to crosstalk.

[0210] 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.

[0211] The insulating layer 125 is located between the resin layer 126 and the organic layer 112R and functions as a protective film to prevent the resin layer 126 from coming into contact with the organic layer 112R.

[0212] 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 metal oxide films such as aluminum oxide film and hafnium oxide film formed by the ALD method, or inorganic insulating films such as silicon nitride film and 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.

[0213] 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.

[0214] The insulating layer 124 is formed when a portion of the protective layer (also called a mask layer or sacrificial layer) used to protect the organic layer 112R remains after etching the organic layer 112R. The insulating layer 124 can be made from the same material that can be used for the insulating layer 125. In particular, it is preferable to use the same material for both the insulating layer 124 and the insulating layer 125, as this allows for the use of common processing equipment and the like.

[0215] The protective layer 121 can be, for example, a single-layer structure or a multi-layer 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.

[0216] Furthermore, an insulating layer 103 is provided on the protective layer 121. For example, an organic material that can be used for the resin layer 126 can be used as the insulating layer 103. By forming the insulating layer 103, the influence of uneven shapes caused by the underlying structure can be reduced, making it easier to form structures such as lens arrays.

[0217] A lens 102R, which is a plano-convex lens, is provided on the insulating layer 103 so as to overlap with the light-emitting element 110R. Furthermore, an insulating layer 104 is provided on the lens 102R.

[0218] The lens 102R is positioned above the light-emitting element 110R (in the direction from which light is emitted). Since the light emitted by the light-emitting element 110R has a certain degree of spread, any light that is not extracted to the outside of the display panel is lost. Therefore, it is preferable to have a high front brightness for the display panel. Because the lens 102R has a convex lens shape, it can be made to focus the light. In other words, it can suppress the divergence of light emitted by the light-emitting element, thereby increasing the light extraction efficiency of the display panel.

[0219] Furthermore, to increase the front brightness of the display panel, it is also effective to use light-emitting elements with higher luminous efficiency. In principle, with tandem organic EL elements, the brightness increases with the number of stacked stages for the same current density, and a two-stage tandem organic EL element can achieve twice the brightness compared to a single-type light-emitting element.

[0220] Furthermore, since the lifespan of an organic EL element depends on the current density, even if the brightness of a tandem organic EL element is doubled, its lifespan will be equivalent to that of a single organic EL element if the current density remains the same. In other words, tandem organic EL elements can be considered an effective technology for increasing the brightness and reliability of organic EL elements.

[0221] A pn-type or PIN-type photodiode can be used as the light-receiving element 110PD. In the light-receiving element 110PD, the amount of charge generated from the light-receiving element 110PD is determined based on the amount of incident light.

[0222] The light-receiving element 110PD can detect infrared light. By using infrared light, which has low visual sensitivity, the impact on the visibility of the display can be suppressed.

[0223] As the light-receiving element 110PD, it is preferable to use an organic photodiode having a layer containing an organic compound. Organic photodiodes can be easily made thinner, lighter, and larger in area, and because they offer a high degree of freedom in shape and design, they can be applied to various display panels.

[0224] In one aspect of the present invention, an organic EL element is used as the light-emitting element 110R, and an organic photodiode is used as the light-receiving element 110PD. The organic EL element and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be incorporated into a display panel using an organic EL element.

[0225] The same manufacturing method as for the light-emitting element 110R can be applied to the light-receiving element 110PD. The island-shaped active layer (also called the photoelectric conversion layer) of the light-receiving element 110PD is not formed using a fine metal mask, but rather by processing after depositing a film that will become the active layer on one surface, so that the island-shaped active layer can be formed with a uniform thickness. In addition, by providing a mask layer on the active layer, the damage that the active layer receives during the display panel manufacturing process can be reduced, and the reliability of the light-receiving element 110PD can be improved.

[0226] The light-receiving element 110PD has a pixel electrode 111PD, an organic layer 112PD, a common layer 114, and a common electrode 113.

[0227] The pixel electrode 111PD of the light-receiving element 110PD is connected to either the source or drain of the transistor 310b by an insulating layer 255a, an insulating layer 255b, and a plug 256b embedded in the insulating layer 255c and insulating layer 243, a conductive layer 241c embedded in the insulating layer 254, and a plug 271b embedded in the insulating layer 261.

[0228] The organic layer 112PD includes at least an active layer and preferably has a plurality of functional layers. For example, the functional layers include carrier transport layers (hole transport layers and electron transport layers) and carrier block layers (hole block layers and electron block layers). It is also preferable to have one or more layers on the active layer. By having other layers between the active layer and the mask layer, it is possible to suppress the exposure of the active layer to the outermost surface during the display panel manufacturing process and reduce damage to the active layer. This can improve the reliability of the photodetector 110PD. Therefore, it is preferable that the organic layer 112PD has an active layer and a carrier block layer (hole block layer or electron block layer) or a carrier transport layer (electron transport layer or hole transport layer) on the active layer.

[0229] The organic layer 112PD is provided on the light-receiving element 110PD but not on the light-emitting element 110R. However, the functional layers other than the active layer included in the organic layer 112PD may have the same material as the functional layers other than the light-emitting layer included in the light-emitting element 110R. In addition, the common layer 114 and the common electrode 113 are a continuous layer shared by the organic layer 112PD and the light-emitting element 110R.

[0230] Here, layers common to the light-receiving element 110PD and the light-emitting element 110R may have different functions in the light-emitting element 110R and in the light-receiving element 110PD. In this specification, components may be referred to based on their function in the light-emitting element 110R. For example, a hole injection layer functions as a hole injection layer in the light-emitting element 110R and as a hole transport layer in the light-receiving element 110PD. Similarly, an electron injection layer functions as an electron injection layer in the light-emitting element 110R and as an electron transport layer in the light-receiving element 110PD. Furthermore, layers common to the light-receiving element 110PD and the light-emitting element 110R may have the same function in the light-emitting element 110R and in the light-receiving element 110PD. For example, a hole transport layer functions as a hole transport layer in both the light-emitting element 110R and the light-receiving element 110PD, and an electron transport layer functions as an electron transport layer in both the light-emitting element 110R and the light-receiving element 110PD.

[0231] An insulating layer 103 is provided on the common electrode 113, similar to the insulating layer 110R. A filter 24 is provided on the insulating layer 103 and on the lens 102R. The filter 24 has a shielding layer 24a and an aperture 24b, and the aperture 24b is positioned to have a region that overlaps with the light-receiving element 110PD.

[0232] The shielding layer 24a has the function of transmitting visible light and shielding infrared light. Examples of materials having such properties include copper phthalocyanine, antimony phthalocyanine, aluminum chloride naphthalocyanine, oxotitanium naphthalocyanine compounds, oxovanadium naphthalocyanine, and tin chloride naphthalocyanine. The shielding layer 24a can be formed, for example, from a material obtained by mixing one or more materials selected from the above with a material that can be used in the resin layer 126.

[0233] A support substrate 163 is provided on the filter 24 via an insulating layer 104. The insulating layer 104 can be made of a material that can be used for the resin layer 126, for example, and is also filled into the opening 24b.

[0234] Furthermore, if the filter 24 is formed of a dielectric multilayer film, it is preferable to perform planarization with an insulating layer 104 and place the filter 24 on the insulating layer 104, as shown in Figure 13A. A support substrate 163 is provided on the filter 24 via an insulating layer 105. The insulating layer 105 can be formed of, for example, a material that can be used for the resin layer 126.

[0235] Furthermore, if the filter 24 is formed of a film, it is preferable to provide it on the support substrate 163, as shown in Figure 13B. Note that the filter 24 shown in Figure 13A can also be formed of a film. Alternatively, the filter 24 shown in Figure 13B can be formed of a dielectric multilayer film.

[0236] [Display Panel 200B] The display panel 200B shown in Figure 14 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.

[0237] 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.

[0238] Here, an insulating layer 345 is provided on the lower surface 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.

[0239] 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 side surface of the plug 343 and functions as a protective layer.

[0240] Furthermore, the substrate 301B has a conductive layer 342 provided below 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 connected to the plug 343.

[0241] 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.

[0242] 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).

[0243] [Display Panel 200C] The display panel 200C shown in Figure 15 has a configuration in which conductive layer 341 and conductive layer 342 are joined via bumps 347.

[0244] As shown in Figure 15, the conductive layers 341 and 342 can be 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.

[0245] [Display Panel 200D] The display panel 200D shown in Figure 16 differs from the display panel 200A mainly in its transistor configuration.

[0246] Transistor 320 (transistors 320a, 320b) 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.

[0247] 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.

[0248] 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.

[0249] 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 part 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.

[0250] 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.

[0251] 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 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.

[0252] 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.

[0253] 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.

[0254] 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 the insulating layer 265, etc. As insulating layer 329, an insulating film similar to that used for insulating layers 328 and 332 can be used.

[0255] A plug 274, which connects to one of the pair of conductive layers 325, is provided so as to be embedded in the insulating layer 265, insulating layer 329, and insulating layer 264. Here, it is preferable that the plug 274 has a conductive layer 274a that covers the sides of the openings of the insulating layer 265, insulating layer 329, insulating layer 264, and insulating layer 328, and a part 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.

[0256] 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.

[0257] 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.

[0258] OS transistors have extremely high field-effect mobility compared to transistors using amorphous silicon. Furthermore, OS transistors exhibit remarkably low source-drain leakage current (also called 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.

[0259] 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 to the source-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.

[0260] 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 allowing control of the current flowing to the light-emitting device. This allows for an increase in the number of grayscale levels in the pixel circuit.

[0261] 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.

[0262] [Display Panel 200E] The display panel 200E shown in Figure 17 has a configuration in which a transistor 310 with a channel formed on a substrate 301 and transistors 320 (transistors 320a, 320b) containing a metal oxide in the semiconductor layer where the channel is formed are stacked.

[0263] 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 layer 251 and the conductive layer 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.

[0264] 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. Transistor 310 can also be used as a transistor constituting various circuits such as arithmetic circuits or memory circuits.

[0265] This configuration allows for the formation of not only pixel circuits but also drive circuits directly beneath the light-emitting and light-receiving elements, making it possible to miniaturize the display panel compared to cases where the drive circuits are located around the display area.

[0266] [Display Panel 200F] The display panel 200F shown in Figure 18 is a configuration in which the transistor 320 of the display panel 200E shown in Figure 17 is replaced with a transistor 330 (vertical transistor: transistors 330a, 330b). Note that the configuration of replacing transistor 320 with transistor 330 can also be applied to the display panel 200D shown in Figure 16.

[0267] Figure 19A shows a cross-sectional view of transistor 330 in the XZ plane. Figure 19B shows a cross-sectional view in the XY plane, including wiring 440.

[0268] The transistor 330 comprises an oxide semiconductor 470, an insulator 430, and a conductor 420. The oxide semiconductor 470 functions as a semiconductor layer, the insulator 430 functions as a gate insulator, and the conductor 420 functions as a gate electrode. The wiring 450 has a region that functions as either the source electrode or the drain electrode of the transistor 330. The wiring 440 has a region that functions as either the source electrode or the drain electrode of the transistor 330.

[0269] The wiring 440 and the insulator 480 are provided with openings 490 that penetrate through them and reach the wiring 450. The openings 490 have a columnar shape with an approximately circular upper surface. This configuration allows for miniaturization or high integration of the memory cell. Preferably, the side surface of the opening 490 is perpendicular to the upper surface of the wiring 450.

[0270] At least a portion of the oxide semiconductor 470 is placed in the opening 490. The oxide semiconductor 470 has a region in contact with the upper surface of the wiring 450, a region in contact with the side surface of the wiring 440, and a region in contact with the side surface of the insulator 480 in the opening 490.

[0271] The insulator 430 is positioned such that at least a portion of it covers the opening 490. The conductor 420 is positioned such that at least a portion of it is located in the opening 490. Preferably, the conductor 420 is provided so as to fill the opening 490, and in order to increase the degree of integration, its shape in a top view is preferably roughly circular.

[0272] As shown in Figure 19A, the oxide semiconductor 470 has a region 470i and regions 470na and 470nb that are provided so as to sandwich region 470i.

[0273] Region 470na is the region of the oxide semiconductor 470 that is in contact with the wiring 450. At least a portion of region 470na functions as one of the source region and drain region of the transistor 330. Region 470nb is the region of the oxide semiconductor 470 that is in contact with the wiring 440. At least a portion of region 470nb functions as the other of the source region and drain region of the transistor 330. As shown in Figure 19B, the wiring 440 is in contact with the entire outer periphery of the oxide semiconductor 470. Therefore, the other of the source region and drain region of the transistor 330 can be formed on the entire outer periphery of the portion of the oxide semiconductor 470 that is formed in the same layer as the wiring 440.

[0274] Region 470i is the region in the oxide semiconductor 470 sandwiched between region 470na and region 470nb. At least a portion of region 470i functions as the channel formation region of transistor 330. In other words, the channel formation region of transistor 330 is formed in a portion of the oxide semiconductor 470 located in the region between wiring 450 and wiring 440. Alternatively, the channel formation region of transistor 330 can be said to be located in the region of the oxide semiconductor 470 that is in contact with the insulator 480 or in a region near it.

[0275] The channel length of transistor 330 is the distance between the source region and the drain region. In other words, the channel length of transistor 330 is determined by the thickness of the insulator 480 on the wiring 450. Figure 19A shows the channel length L of transistor 330 with a dashed double arrow. In a cross-sectional view, the channel length L is the distance between the end of the region where the oxide semiconductor 470 and the wiring 450 are in contact and the end of the region where the oxide semiconductor 470 and the wiring 440 are in contact. In other words, the channel length L corresponds to the length of the side surface of the insulator 480 on the opening 490 side in a cross-sectional view.

[0276] In planar transistors, the channel length is limited by the exposure limit of photolithography, making further miniaturization difficult. However, in one embodiment of the present invention, the channel length can be set by the film thickness of the insulator 480. Therefore, the channel length of the transistor 330 can be made into an extremely fine structure below the exposure limit of photolithography (for example, 60 nm or less, 50 nm or less, 40 nm or less, 30 nm or less, 20 nm or less, or 10 nm or less, and 1 nm or more, or 5 nm or more). This makes it possible to increase the on-current of the transistor 330.

[0277] Furthermore, as described above, a channel formation region, a source region, and a drain region can be formed in the aperture 490. This reduces the area occupied by the transistor 330 compared to a planar transistor where the channel formation region, source region, and drain region are separately provided on the XY plane. This allows for an increase in pixel density.

[0278] Thus, a transistor having a channel-forming region along the side surface of the insulator 480 at the opening 490 is also called a vertical transistor.

[0279] Furthermore, in the XY plane including the channel formation region of the oxide semiconductor 470, the oxide semiconductor 470, the insulator 430, and the conductor 420 are arranged concentrically, similar to Figure 19B. Therefore, the side surface of the conductor 420 located at the center faces the side surface of the oxide semiconductor 470 via the insulator 430. In other words, in a top view, the entire perimeter of the oxide semiconductor 470 becomes the channel formation region. In this case, for example, the channel width of the transistor 330 is determined by the length of the outer circumference of the oxide semiconductor 470. That is, the channel width of the transistor 330 can be said to be determined by the size of the maximum width of the opening 490 (the diameter if the opening 490 is circular in a top view). Figures 19A and 19B show the maximum width D of the opening 490 with a double-headed arrow. Figure 19B shows the channel width W of the transistor 330 with a double-headed arrow.

[0280] When forming the aperture 490 using photolithography, the maximum width D of the aperture 490 is limited by the exposure limit of the photolithography. Furthermore, the maximum width D of the aperture 490 is set by the film thickness of the oxide semiconductor 470, insulator 430, and conductor 420 provided in the aperture 490. The maximum width D of the aperture 490 is, for example, 5 nm or more, 10 nm or more, or 20 nm or more, and preferably 100 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, or 30 nm or less. Note that if the aperture 490 is circular in a top view, the maximum width D of the aperture 490 corresponds to the diameter of the aperture 490, and the channel width W can be calculated as "D × π".

[0281] Furthermore, in a memory device according to one aspect of the present invention, it is preferable that the channel length L of the transistor 330 is at least smaller than the channel width W of the transistor 330. In one aspect of the present invention, the channel length L of the transistor 330 is 0.1 times or more and 0.99 times or less, preferably 0.5 times or more and 0.8 times or less, the channel width W of the transistor 330. By adopting such a configuration, a transistor with good electrical characteristics and high reliability can be realized.

[0282] Further, by forming the opening 490 so as to be substantially circular in a top view, the oxide semiconductor 470, the insulator 430, and the conductor 420 are provided concentrically. As a result, the distance between the conductor 420 and the oxide semiconductor 470 becomes substantially uniform, so that a gate electric field can be applied to the oxide semiconductor 470 substantially uniformly.

[0283] In the channel formation region of a transistor using an oxide semiconductor for the semiconductor layer, it is preferable that the oxygen deficiency is less or the impurity concentration such as hydrogen, nitrogen, and metal elements is lower than that in the source region and the drain region. For example, the concentration of aluminum in the channel formation region of the oxide semiconductor is preferably 1×10 ２２ atoms / cm ３ or less, more preferably 1×10 ２１ atoms / cm ３ or less, still more preferably 1×10 ２０ atoms / cm ３ or less, still more preferably 5×10 １９ atoms / cm ３ or less, still more preferably 1×10 １９ atoms / cm ３ or less, still more preferably 5×10 １８ atoms / cm ３ or less, still more preferably 1×10 １８ [[ID=3l]]atoms / cm ３ or less is even more preferable.

[0284] Further, since hydrogen near the oxygen deficiency may form a defect in which hydrogen enters the oxygen deficiency (hereinafter sometimes referred to as V Ｏ H) and generate electrons serving as carriers, it is preferable that V Ｏ H is also reduced in the channel formation region. Thus, the channel formation region of the transistor is a high-resistance region with a low carrier concentration. Therefore, it can be said that the channel formation region of the transistor is i-type (intrinsic) or substantially i-type.

[0285] Further, in the source region and the drain region of a transistor using an oxide semiconductor for the semiconductor layer, the oxygen deficiency is larger and V ＯThis region has a high concentration of hydrogen (H), or high concentrations of impurities such as hydrogen, nitrogen, and metallic elements, resulting in increased carrier concentration and low resistance. In other words, the source and drain regions of a transistor are n-type regions with higher carrier concentration and lower resistance compared to the channel formation region.

[0286] In Figure 19A and other figures, the opening 490 is provided such that its side surface is perpendicular to the top surface of the wiring 450, but the present invention is not limited to this. For example, the side surface of the opening 490 may be tapered.

[0287] This embodiment can be implemented in appropriate combination with other embodiments and examples described herein, at least in part.

[0288] (Embodiment 3) This embodiment describes an indium oxide film that can be used in the semiconductor layer of a transistor in a display panel according to one aspect of the present invention.

[0289] In this specification, indium oxide having at least a crystalline portion or crystalline region in the film is referred to as crystalline indium oxide (crystal IO) or crystalline indium oxide (crystalline IO). Examples of crystal IO or crystalline IO include single-crystal indium oxide, polycrystalline indium oxide, and microcrystalline indium oxide.

[0290] Indium oxide is a semiconductor material with completely different physical properties from oxide semiconductors such as In-Ga-Zn oxide (hereinafter also referred to as IGZO) and zinc oxide.

[0291] The carrier concentration dependence of the hole (Hall) mobility of indium oxide, silicon, and IGZO is described. Figure 20A shows silicon (Si) and indium oxide (InO Ｘ Figure 20B is a schematic diagram of the carrier concentration dependence of hole mobility with respect to IGZO.

[0292] First, as indicated by the arrows in Figure 20B, IGZO tends to show higher hole mobility as the carrier concentration increases. On the other hand, as indicated by the arrows in Figure 20A, indium oxide tends to show higher hole mobility as the carrier concentration decreases (see Non-Patent Literature 1). This trend is similar to that of silicon, where the lower the concentration of dopants (impurities) in the material, the less impurity scattering occurs and the higher the hole mobility. In other words, the higher the purity and intrinsic nature of indium oxide, the higher its hole mobility. From these results, it can be said that indium oxide, unlike IGZO, is a material with physical properties similar to silicon. Note that the properties of indium oxide shown in Figure 20A are assumed to be those of a single crystal. Therefore, when indium oxide is not a single crystal (for example, polycrystalline), the properties may differ from those shown in Figure 20A.

[0293] In Figure 20A, the range R1 with low carrier concentration exhibits extremely high hole mobility, making it a suitable range of carrier concentration for, for example, the channel formation region of a transistor. For example, in the case of indium oxide, the range R1 has a carrier concentration of 1 × 10⁻⁶. １５ cm −３ This range includes, for example, 1 × 10 １４ cm −３ The above is 1 x 10 １８ cm −３ The range is as follows: By sufficiently reducing the carrier concentration, the hole mobility value can be increased to 270 cm⁻¹. ２ It can be expected to be raised to the level of / (V・s).

[0294] Furthermore, in indium oxide, the region where the carrier concentration is in the range R1 may contain elements that lower the carrier concentration. Examples of elements that lower the carrier concentration include magnesium, calcium, zinc, cadmium, and copper. By substituting these elements for indium, the carrier concentration can be lowered. Other elements that lower the carrier concentration include nitrogen, phosphorus, arsenic, and antimony. For example, by substituting nitrogen, phosphorus, arsenic, or antimony for oxygen, the carrier concentration can be lowered.

[0295] On the other hand, the range R2 with high carrier concentration has low electrical resistance and can be said to be a suitable range of carrier concentration for applications such as the source and drain regions of a transistor, or resistors, or transparent conductive films. The range R2 is when the carrier concentration value is 1 × 10⁻⁶ ２０ cm −３ This range includes, for example, 1 × 10 １９ cm −３ The above is 1 x 10 ２２ cm −３ The range is as follows: By making the carrier concentration sufficiently high, the resistivity can be increased to 1 × 10⁻⁶. −４ It is expected that the level can be reduced to below Ω·cm.

[0296] Furthermore, in the indium oxide, the region where the carrier concentration is in the range R2 may contain elements that increase the carrier concentration. For example, it is preferable to include elements common to the source and drain electrodes of the transistor. Examples of elements that increase the carrier concentration include titanium, zirconium, hafnium, tantalum, tungsten, molybdenum, tin, silicon, and boron. In particular, it is more preferable to use elements in which the oxide is conductive or semiconducting.

[0297] In this way, indium oxide uses regions with low carrier concentrations for the transistor's channel formation region and regions with high carrier concentrations for the transistor's source and drain regions. In other words, indium oxide can be said to be an oxide in which valence electron control is possible. In contrast, with IGZO, strain may be formed in the source and drain regions due to stress on the electrodes in contact with IGZO, and an n-type region may be formed. On the other hand, unlike IGZO, indium oxide allows for valence electron control, so it does not require the formation of strain in the film as in IGZO. Less strain in the film is expected to improve reliability. For example, by creating regions with carrier concentrations in the range R1 and range R2 shown in Figure 20A within the indium oxide film, a so-called n-i-n junction (a junction of an n-type region, an i-type region, and an n-type region) can be created. Valence electron control in silicon transistors is generally known. On the other hand, valence electron control in indium oxide transistors is a novel technological concept that would not normally be conceived.

[0298] By applying the above technical concept, the indium oxide transistor described herein has two or more, preferably three or more, more preferably four or more, and most preferably five of the following features (1) to (5): (1) High on-current (in other words, high mobility). (2) Low off-current. (3) Normally off is possible. (4) High reliability. (5) High cutoff frequency (fT). For example, the indium oxide transistor described herein has high mobility, low off-current, and is normally off. This transistor is different from a transistor that is high mobility and normally on.

[0299] Next, we will describe indium oxide films applied to transistors. Indium oxide films are preferably crystalline (i.e., they have crystal grains). Examples of films with crystal grains include single-crystal films, polycrystalline films, or amorphous films containing crystal grains (also called microcrystalline films). In particular, polycrystalline films are preferred for indium oxide films, and single-crystal films are more preferred. Single-crystal films do not have crystal grain boundaries. Impurities that inhibit carrier flow (typically insulating impurities, insulating oxides, etc.) tend to segregate at crystal grain boundaries. By using single-crystal films, carrier scattering at crystal grain boundaries can be suppressed, enabling the realization of transistors exhibiting high field-effect mobility. Furthermore, it has the excellent effect of suppressing variations in transistor characteristics caused by these crystal grain boundaries.

[0300] Furthermore, polycrystalline films are preferable because they can reduce carrier scattering and exhibit high field-effect mobility compared to microcrystalline or amorphous films. When using polycrystalline films, it is preferable to use films with the largest possible grain size and few grain boundaries. In a transistor to which a polycrystalline indium oxide film is applied, if there are no grain boundaries in the channel formation region, or if no grain boundaries are observed, the channel formation region is located within the single-crystal region contained in the polycrystalline film, and therefore it can be considered a transistor to which single-crystal indium oxide is applied.

[0301] The crystallinity of indium oxide can be analyzed, for example, by X-ray diffraction (XRD), transmission electron microscopy (TEM), or electron diffraction (ED). Alternatively, a combination of these methods may be used for analysis.

[0302] Furthermore, in this specification, a semiconductor layer in which no grain boundaries are observed in the channel-forming region, a semiconductor layer in which the channel-forming region is contained within a single crystal grain, or a semiconductor layer in which the direction of the crystal axes is the same in at least two regions within the channel-forming region can be called a single crystal film. In addition, a semiconductor layer in which, within a single crystal grain in the channel-forming region, the direction of other crystal axes changes continuously with respect to a certain crystal axis or crystal orientation as the axis of rotation can be called a single crystal film.

[0303] The channel formation region refers to the area within the semiconductor layer that overlaps with (or faces) the gate electrode via the gate insulating layer, and is located between the region in contact with the source electrode and the region in contact with the drain electrode. The current path in the channel formation region is the shortest distance between the source electrode and the drain electrode. Therefore, the crystal grains, grain boundaries, crystal axes, and crystal orientation in the channel formation region can be confirmed by cross-sectional observation including the semiconductor layer, source electrode, and drain electrode.

[0304] The indium oxide film in the channel-forming region is preferable to have a low impurity concentration. Impurities in the indium oxide film in the channel-forming region can act as a scattering source for carriers, and thus can cause a decrease in field-effect mobility. Furthermore, these impurities can also inhibit crystal growth in the indium oxide film. Examples of impurities in the indium oxide film include boron and silicon. The concentration of these impurities in the indium oxide film is preferably 0.1% or less, and more preferably 0.01% (100 ppm) or less. Note that elements such as carbon and hydrogen may be present in the deposition gas or precursor during film formation, and may remain in the indium oxide film in higher concentrations than the impurities mentioned above.

[0305] Furthermore, the indium oxide film in the channel-forming region may contain elements that can become trivalent cations like indium, as long as their crystals maintain a cubic crystal structure (Bixbite type). Examples include Group 13 elements of the periodic table such as gallium and aluminum, and Group 3 elements of the periodic table. Since these elements mainly exist as trivalent cations in the oxide, the carrier concentration of indium oxide can be kept low.

[0306] By using such an indium oxide film in a transistor, the field-effect mobility of the transistor can be increased to 50 cm². ２ / (V·s) or more, preferably 100 cm ２ / (V·s) or more, more preferably 150 cm ２ / (V·s) or more, more preferably 200 cm ２ / (V·s) or more, more preferably 250 cm ２ It can be set to (V・s) or more.

[0307] One of the characteristics of indium oxide films is that they have higher oxygen permeability (diffusivity) compared to IGZO films. As shown in Figure 20C, indium oxide films (InO Ｘ Oxygen (O) diffusing into the indium oxide film passes through the indium oxide film and oxygen molecules (O) ２ It is released as water molecules (H) by reacting with hydrogen contained in the membrane. ２ It may also be released as O. Furthermore, oxygen deficiencies (V) can form in the membrane. Ｏ If oxygen atoms are present, diffusing oxygen atoms will fill the oxygen deficiency. Indium oxide films allow oxygen to diffuse easily, so they can be said to fill oxygen deficiencies more easily than IGZO films.

[0308] Thus, because indium oxide films are more likely to reduce oxygen vacancies in the film compared to IGZO films, applying such indium oxide films to transistors makes it possible to realize transistors with extremely high reliability.

[0309] Furthermore, as shown in Figure 20C, the indium oxide film diffuses hydrogen. Hydrogen diffusing into the indium oxide film from the outside permeates the film and forms hydrogen molecules (H ２ It is released as ) or, by reacting with oxygen contained in the membrane, it is released as water molecules.

[0310] Transistors using indium oxide films are storage-type transistors that use electrons as majority carriers. Assuming that the carrier relaxation time is constant, the smaller the effective mass of electrons (carriers), the higher the electron mobility. In other words, by using indium oxide, which has a small effective mass of electrons, in a transistor, the on-current or field-effect mobility of the transistor can be increased.

[0311] Table 1 shows single crystal indium oxide (here, In ２ O ３ The effective masses of indium oxide and single-crystal silicon (Si) are shown below. As shown in Table 1, indium oxide is characterized by a small effective electron mass and a large effective hole mass. Furthermore, the effective electron mass of indium oxide is almost independent of the crystal orientation. Therefore, by using crystalline indium oxide in transistors, transistors with high field-effect mobility and high frequency characteristics (also called f-characteristics) can be realized. In addition, because the effective hole mass is large, transistors with extremely low off-currents can be realized. For example, by applying an indium oxide film to a vertical transistor, the off-current per 1 μm of channel width is 1 fA (1 × 10⁻¹⁶) in an environment of 125°C. −１５ A) Less than or equal to, or 1aA (1 × 10 −１８ A) Less than or equal to 1aA (1 × 10) in a room temperature (25°C) environment. −１８ A) Less than or equal to, or 1zA (1 × 10⁻¹⁰ −２１ A) The following is possible. Also, as shown in Table 1, indium oxide has a smaller effective electron mass and a larger effective hole mass than silicon, so it may be possible to realize a transistor with higher field-effect mobility and lower off-current than a Si transistor.

[0312]

[0313] It is preferable to provide a seed layer so as to be in contact with at least a portion of the crystalline indium oxide film. It is preferable to use a material containing crystals with a small difference in lattice constant (also called lattice mismatch) with the indium oxide for the seed layer. This improves the crystallinity of the indium oxide film. A substrate (e.g., a single-crystal substrate) may be used as one of the layers in contact with at least a portion of the crystalline indium oxide film.

[0314] One method for evaluating the degree of lattice mismatch is to use the following lattice mismatch value. The lattice mismatch Δa [%] of the crystals in the formed film (in this case, the indium oxide film) relative to the crystals in the seed layer is given by Δa = ((L １ -L ２ ) / L ２ It is calculated as ) × 100. Here L １ L is the length of the unit cell vector of the crystals in the formed film, or the lattice constant. ２ This is the length of the unit cell vector of the crystal in the seed layer, or the lattice constant.

[0315] The lattice mismatch Δa between the seed layer and the indium oxide film is preferably small in absolute value, and most preferably zero. For example, Δa can be -5% or more and 5% or less, preferably -4% or more and 4% or less, more preferably -3% or more and 3% or less, and even more preferably -2% or more and 2% or less.

[0316] Here, the indium oxide crystal has a cubic structure (bixbite type). For example, yttria-stabilized zirconia (YSZ) crystals can have a cubic structure (fluorite type). The lattice mismatch of the indium oxide crystal with respect to the cubic YSZ crystal is in the range of -2% to 2%, and a single crystal film of indium oxide can be epitaxially grown on a YSZ substrate.

[0317] Furthermore, the crystal structure of the seed layer and the crystal structure of the indium oxide film do not necessarily have to be the same in terms of crystal system or crystal orientation. For example, a film with a hexagonal or trigonal crystal structure can be used beneath an indium oxide film with a cubic crystal structure. For example, by setting the crystal orientation of the surface of the seed layer to

[001] and the crystal orientation of the underside of the indium oxide film to

[111] , the requirements related to crystal orientation necessary for epitaxial growth can be met. Examples of hexagonal or trigonal crystals include wurtzite-type structures and YbFe. ２ O ４ Type structure, Yb ２ Fe ３ O ７ These include type structures and their modified type structures. YbFe ２ O ４ Type structure or Yb ２ Fe ３ O ７ An example of a crystal having a type structure is IGZO.

[0318] This embodiment can be implemented in appropriate combination with other embodiments and examples described herein, at least in part.

[0319] OUT: Wiring, 14: Pixel array, 15: Circuit, 16: Circuit, 17: Circuit, 18: Circuit, 19: Circuit, 20: Display panel, 21: Pixel, 21a: Pixel, 21b: Pixel, 22: Sub-pixel, 22B: Sub-pixel, 22G: Sub-pixel, 22R: Sub-pixel, 22W: Sub-pixel, 23: Sub-pixel, 24: Filter, 24a: Shielding layer, 24b: Aperture, 25: Region, 26: Region, 30: Reflective / refracting optical system, 31: Linear polarizer, 32: Phase difference plate, 34: Half mirror, 35: Phase difference plate, 36: Reflective polarizer, 40: Eye, 41: Retina, 42: Pupil, 51: Lens, 52: Support, 53: Support 57: Optical axis, 70: Display unit, 71: Housing, 75: Holder, 80: Light source, 102R: Lens, 103: Insulating layer, 104: Insulating layer, 105: Insulating layer, 110PD: Photodetector, 110R: Light-emitting element, 111PD: Pixel electrode, 111R: Pixel electrode, 112PD: Organic layer, 112R: Organic layer, 113: Common electrode, 114: Common layer, 121: Protective layer, 124: Insulating layer, 125: Insulating layer, 126: Resin layer, 163: Support substrate, 200A: Display panel, 200B: Display panel, 200C: Display panel, 200D: Display panel, 200E: Display panel, 200F: Display panel, 240: Capacity, 240a: Capacity, 240b: Capacity, 241: Conductive layer, 241a: Conductive layer, 241b: Conductive layer, 241c: Conductive layer, 243: Insulating layer, 245: Conductive layer, 245a: Conductive layer, 245b: Conductive layer, 251: Conductive layer, 252: Conductive layer, 254: Insulating layer, 255a: Insulating layer, 255b: Insulating layer, 255c: Insulating layer, 256a: Plug, 256b: Plug, 261: Insulating layer, 262: Insulating layer, 263: Insulating layer, 264: Insulating layer, 265: Insulating layer, 271: Plug, 271a: Plug, 271b: Plug, 274: Plug, 274a: Conductive Layer, 274b: conductive layer, 301: substrate, 301A: substrate, 301B: substrate, 310: transistor, 310A: transistor, 310a: transistor, 310B: transistor, 310b: transistor, 311: conductive layer, 312: low resistance region, 313: insulating layer, 314: insulating layer, 315: element isolation layer, 320: transistor, 320a: transistor, 320b: 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, 330: transistor,330a: Transistor, 330b: Transistor, 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, 420: Conductor, 430: Insulator, 440: Wiring, 450: Wiring, 470: Oxide semiconductor, 470i: Region, 470na: Region, 470nb: Region, 480: Insulator, 490: Opening

Claims

An electronic device having a display panel, a reflective / refracting optical system, and a light source, which is worn in front of the user's eyes, The aforementioned reflective and refractive optical system is positioned opposite the display surface of the display panel, The aforementioned display panel is A pixel having adjacent light-emitting and light-receiving elements, and a filter, The filter has a shielding layer and an opening, The shielding layer has the function of transmitting visible light and blocking infrared light. The opening has a region that overlaps with the light-receiving element, The aforementioned reflective / refracting optical system is A half-mirror that transmits infrared light and semi-transmits / semi-reflects visible light, The light-emitting element has a function of forming an image of visible light on the retina of the eye, An electronic device having the function of transmitting infrared light emitted by the light source and reflected by the surface of the eye. 　 In claim 1, The aforementioned reflective and refractive optical system is an electronic device having a configuration in which a linear polarizer, a first phase difference plate, the half mirror, a second phase difference plate, and a reflective polarizer are arranged in that order in one direction from the display panel side. 　 In claim 1, The filter is an electronic device having a resin layer that transmits infrared light at the opening. 　 In claim 1, An electronic device having a planarization film between the filter, the light-emitting element and the light-receiving element. 　 In claim 1, An electronic device having a support substrate between the filter, the light-emitting element and the light-receiving element. 　 In claim 1, An electronic device having a convex lens between the light-emitting element and the filter. 　 In claim 1, The shielding layer is an electronic device having one or more materials selected from copper phthalocyanine, antimony phthalocyanine, aluminum chloride naphthalocyanine, oxotitanium naphthalocyanine compounds, oxovanadium naphthalocyanine, and tin chloride naphthalocyanine. 　 In claim 1, The shielding layer is a dielectric multilayer film in an electronic device. 　 An electronic device having a display panel, a reflective / refracting optical system, a filter, and a light source, which is worn in front of the user's eyes, The aforementioned reflective and refractive optical system is positioned opposite the display surface of the display panel, The filter is positioned between the display panel and the eye. The display panel has pixels having adjacent light-emitting and light-receiving elements, The filter has a shielding layer and an opening, The shielding layer has the function of transmitting visible light and blocking infrared light. The aforementioned reflective / refracting optical system is A half-mirror that transmits infrared light and semi-transmits / semi-reflects visible light, The light-emitting element has a function of forming an image of visible light on the retina of the eye, An electronic device having the function of transmitting infrared light emitted by the light source and reflected by the surface of the eye. 　 In claim 9, The filter is positioned between the display surface of the display panel and the reflective / refracting optical system, and the filter has one aperture. 　 In claim 9, The filter is positioned between the display surface of the display panel and the reflective / refracting optical system, and the aperture is a plurality of apertures in the electronic device. 　 In claim 9, The aforementioned reflective and refractive optical system is an electronic device having a configuration in which a linear polarizer, a first phase difference plate, the half mirror, a second phase difference plate, and a reflective polarizer are arranged in that order in one direction from the display panel side. 　 In any one of claims 1 to 12, The pixel has a transistor connected to the light-emitting element and the light-receiving element, and the transistor has a metal oxide in the channel-forming region of the electronic device. 　 In claim 13, The aforementioned metal oxide is indium oxide in an electronic device.

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