Electronic device

Abstract

The purpose of the present invention is to provide an electronic device having a myopia ameliorating effect. An electronic device according to the present invention includes a display panel (20), a catadioptric optical system (30), and a light source (80), wherein the display panel (20) includes a light-emitting element and a light-receiving element adjacent to each other within each pixel (21). The light-receiving element is used as a sensor for visual axis detection and diopter adjustment. The catadioptric optical system (30) includes a first half mirror (33) and a second half mirror (34). Furthermore, a first position adjustment mechanism (61) and a second position adjustment mechanism (62) for moving the first half mirror (33) and the second half mirror (34), respectively, are provided so that the focal length of the catadioptric optical system (30) can be adjusted so that an image appears farther away within the range in which a user can bring the image into focus, thereby enabling relaxation of the ciliary muscle.

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 display panels used in these electronic devices include those equipped with liquid crystal elements, organic EL (Electroluminescence) elements, or light-emitting diodes (LEDs). Because display devices equipped with light-emitting elements do not require a backlight, which is necessary for liquid crystal displays, they can be made thin, lightweight, high-contrast, and low-power consumption displays.

[0006] In goggle-type devices, infrared light sensors are sometimes implemented to obtain dynamic information about the eyes or their vicinity, which is necessary for gaze detection and other purposes. For example, Patent Document 1 discloses an electronic device equipped with a sensor function that detects fatigue or abnormalities from blinking movements. Patent Document 2 also discloses an electronic device that uses a display device with light-receiving devices in its pixels to adjust the user's diopter.

[0007] International Publication No. 2022 / 234383, Japanese Patent Publication No. 2023-103971

[0008] The human eye has a cornea and a lens that act as lenses, and by passing light through these and forming an image on the retina, we can see objects. In order to focus light emitted from objects at different distances from the eye onto the retina, it is necessary to change the thickness of the lens and thus change the refractive power of light in the eye.

[0009] To focus light emitted from a nearby object onto the retina, the ciliary muscle is tensed, thickening the lens and increasing the refraction of light. To focus light emitted from a distant object onto the retina, the ciliary muscle is relaxed, thinning the lens and decreasing the refraction of light. In this way, the human eye can adjust its focus by changing its refractive power by tensing or relaxing the ciliary muscle according to the distance from the object.

[0010] When you continuously look at objects that are relatively close to your eyes, such as a smartphone or a book, and the ciliary muscle remains tense for an extended period, the ability to relax the ciliary muscle temporarily becomes impaired. This condition is called pseudomyopia, and it makes it difficult to focus on distant objects. Pseudomyopia is a treatable condition and is known to improve through training such as looking at distant objects to relax the tense ciliary muscle, or alternately looking at near and far objects to contract and relax the ciliary muscle.

[0011] However, the above training of the ciliary muscle takes time to show an improvement effect. Therefore, when the will to improve is insufficient or when there is no interest in the training content, it is difficult to maintain continuity. As a result, the symptoms often progress to chronic myopia without the improvement of pseudomyopia. To continue the training of the ciliary muscle, it is preferable to use a method that is easy to incorporate into daily life and that the user does not perceive as training.

[0012] Therefore, one of the objectives of one aspect of the present invention is to provide an electronic device having an effect of improving myopia. Or, one of the objectives is to provide an electronic device having an effect of relaxing the ciliary muscle. Or, one of the objectives is to provide an electronic device capable of automatically adjusting the diopter. Or, one of the objectives is to provide an electronic device provided with a light source, a sensor, and an optical element. Or, one of the objectives is to provide an electronic device capable of detecting motion information of the user's eye or in its vicinity. Or, one of the objectives is to provide a novel electronic device. Or, one of the objectives 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 need to solve all of these problems. Note that other problems will become apparent from the description of the specification, drawings, claims, etc., and it is possible to extract these other problems from the description of the specification, drawings, claims, etc.

[0014] One aspect of the present invention relates to an electronic device having an effect of improving myopia.

[0015] One aspect of the present invention is an electronic device having a display panel, a reflective refractive optical system, and a light source, and being worn in front of an eye. The reflective refractive optical system is disposed to face the display surface of the display panel. The display panel has pixels having light-emitting elements and light-receiving elements. The light-emitting elements have a function of emitting visible light, and the light-receiving elements have a function of photoelectrically converting infrared light. The reflective refractive optical system has a first half mirror, a second half mirror, a first position adjustment mechanism, and a second position adjustment mechanism. The first half mirror has a function of transmitting visible light and a function of semi-transmitting and semi-reflecting infrared light. The second half mirror has a function of transmitting infrared light and a function of semi-transmitting and semi-reflecting visible light. The first position adjustment mechanism has a function of moving the first half mirror along the perpendicular line of the display surface. The second position adjustment mechanism has a function of moving the second half mirror along the perpendicular line of the display surface. The light source is an electronic device having a function of emitting infrared light.

[0016] By moving the first half mirror to the first position, a first function of imaging infrared light reflected on the surface of the eye onto the light-receiving element and imaging the eye and its vicinity, and by moving the first half mirror to the second position, a second function of imaging infrared light reflected on the retina of the eye onto the light-receiving element and measuring the focal length of the reflective refractive optical system including the eye. Using the second function, the position where the second half mirror is moved can be determined, and a third function of imaging visible light emitted by the light-emitting element onto the retina of the eye can be achieved.

[0017] After the operation of the third function, a fourth function of moving the second half mirror so that the virtual image of the display surface appears farther can be achieved. Also, the operation of the fourth function can be performed using the first function.

[0018] The reflective refractive optical system can have a configuration in which a linear polarizing plate, a first retardation plate, one of the first half mirror and the second half mirror, the other of the first half mirror and the second half mirror, a second retardation plate, and a reflective polarizing plate are arranged in one direction in this order from the display panel side.

[0019] The reflective / refractive optical system comprises a lens and a third position adjustment mechanism, the third position adjustment mechanism having the function of moving the lens along a perpendicular line to the display surface.

[0020] The first to third position adjustment mechanisms are preferably of the helicoid type, cylindrical cam type, rack and pinion type, or ball screw type.

[0021] The first half-mirror and the second half-mirror may each have a concave surface.

[0022] 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.

[0023] According to one aspect of the present invention, an electronic device having the effect of improving myopia can be provided. Alternatively, an electronic device having the effect of relaxing the ciliary muscle can be provided. Alternatively, an electronic device that can automatically adjust diopter can be provided. Alternatively, an electronic device equipped with a light source, a sensor, and an optical element can be provided. Alternatively, an electronic device that can detect movement information of the user's eye or its vicinity can be provided. Alternatively, a novel electronic device can be provided. Alternatively, a novel semiconductor device can be provided, etc.

[0024] 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.

[0025] Figure 1 is a diagram illustrating electronic equipment. Figures 2A and 2B illustrate the position of the virtual image in a reflective-refracting optical system. Figure 3 is a diagram illustrating a reflective-refracting optical system. Figure 4 is a diagram illustrating a reflective-refracting optical system. Figures 5A and 5B illustrate the simulation results of a half-mirror. Figures 6A, 6B, 6C, 6D, 6E, 6F, 6G, and 6H illustrate the support and half-mirror. Figures 7A, 7B, 7C, 7D, and 7E illustrate the light source. Figures 8A and 8B illustrate the operating modes of electronic equipment. Figures 9A and 9B illustrate the operating modes of electronic equipment. Figure 10 is a diagram illustrating the operating modes of electronic equipment. Figure 11 is a diagram illustrating a reflective-refracting optical system. Figure 12 is a diagram illustrating a reflective-refracting optical system. Figures 13A, 13B, 13C, 13D, and 13E illustrate a display device. Figures 14A, 14B, 14C, and 14D illustrate a display device. Figures 15A, 15B, 15C, 15D, 15E, 15F, and 15G illustrate a display device and a reflective / refracting optical system. Figures 16A, 16B, and 16C illustrate a pixel circuit. Figures 17A and 17B are perspective views illustrating electronic equipment. Figure 18 illustrates an example configuration of a display device. Figure 19 illustrates an example configuration of a display device. Figure 20 illustrates an example configuration of a display device. Figure 21 illustrates an example configuration of a display device. Figure 22 illustrates an example configuration of a display device. Figure 23 illustrates an example configuration of a display device. Figures 24A and 24B illustrate a transistor.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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."

[0031] 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."

[0032] 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.

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

[0034] One aspect of the present invention is an electronic device worn in front of the eye that has the function of improving myopia. In recent years, there has been an increase in young people whose eyesight has deteriorated due to prolonged use of smartphones and game consoles. In the early stages of vision deterioration, it is often a state of pseudomyopia in which the ciliary muscle, which changes the refractive power of the lens, remains in a state of tension. Pseudomyopia can be improved by training that appropriately provides conditions for the ciliary muscle to relax. Furthermore, even in cases of chronic myopia, some degree of vision recovery is possible.

[0035] An electronic device according to one aspect of the present invention functions as a VR goggle, is capable of detecting dynamic information from the eyes and their vicinity, and adjusting diopter, and includes a display panel, a reflective / refractive optical system, and a light source.

[0036] The display panel has adjacent light-emitting elements (also called light-emitting devices) and light-receiving elements (also called light-receiving devices) within each pixel. The reflective / refractive optical system forms two different optical paths: one between the surface of the eye and the light-receiving element, and another between the light-emitting element and the retina. The light source functions as a source of infrared light detected by the light-receiving element.

[0037] To improve the accuracy of eye tracking, it is preferable to accurately detect the movement of the eyeball. To accurately detect the precise 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 eye tracking.

[0038] Furthermore, electronic devices can detect the position and degree of refraction of the retina by acquiring the light emitted by a light source and reflected by the retina using a photodetector. Therefore, the focal length of the reflective and refractive optical system, including the eye, can be measured, and diopter adjustment can be performed to adjust the optical distance between the light-emitting element and the retina according to the said focal length.

[0039] Furthermore, electronic devices can automatically adjust the diopter according to the user's visual acuity, and then adjust the focal length of the reflective / refractive optical system so that the image (virtual image) appears further away, within the range in which the user can focus on the image (virtual image). Looking at something far away causes the ciliary muscle to relax, gradually relieving tension.

[0040] Therefore, each time the electronic device according to one aspect of the present invention is used, the user is trained to focus on distant objects, thereby improving myopia. Furthermore, since the electronic device functions as a VR headset, the user can select and use various content according to their preferences. Thus, it can be incorporated into daily life without the user consciously thinking of it as training to improve myopia, thus increasing its likelihood of continuation.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] The display panel 20 has pixels 21 on its display surface, and each pixel 21 has a sub-pixel 22 having a light-emitting element that emits visible light, and a sub-pixel 23 having a photodetector that converts infrared light into photoelectric light. The light-emitting element is used for display, and the photodetector is used to acquire an image of the eye 40 for eye tracking and diopter adjustment. The reflective-refractive optical system 30 has a half-mirror 33, a half-mirror 34, and a reflective polarizer 36. Note that in Figure 1, elements related to polarization conversion and elements related to light refraction such as lenses are omitted. Details of these will be described later.

[0046] 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 reflected and refracted repeatedly 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.

[0047] 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).

[0048] In order to image the surface of the eye 40 with the sub-pixel 23 having a light-receiving element, the light emitted from the surface of the eye 40 (for example, the pupil 42) (reflected light from the light source 80 emitted to the surface of the eye 40) must be imaged by the sub-pixel 23. However, when the sub-pixels 22 and 23, which are adjacent and formed on substantially the same plane within the pixel 21, are used 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 the 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.

[0049] 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, and the optical path is made different from that between the sub-pixel 22 and the retina 41 to focus the infrared light onto the sub-pixel 23. Since infrared light has low visual sensitivity, it does not affect the visibility of the image, making it suitable light for detecting information from the eye or its vicinity.

[0050] Thus, to use light from two different wavelength ranges (visible light and infrared light) and create different optical paths (focal lengths) for each, it is possible to use half-mirrors in each optical path so that the light from one wavelength range does not interfere with the other.

[0051] Specifically, as shown in Figure 1, the half mirrors 33 located in each optical path are half mirrors that transmit visible light (VL) and semi-transmit and semi-reflect infrared light (IR). In addition, the half mirrors 34 located in each optical path are half mirrors that transmit infrared light (IR) and semi-transmit and semi-reflect visible light (VL). In other words, the half mirrors 33 do not contribute to the visible light optical path, and the half mirrors 34 do not contribute to the infrared light optical path.

[0052] The half mirrors 33 and 34 can be given different curvatures, allowing for adjustment of the focal length in each optical path. In Figure 1, the half mirrors 33 and 34 are shown in that order from the display panel 20 side, but they may be swapped.

[0053] Furthermore, a position adjustment mechanism 60 (position adjustment mechanism 61, position adjustment mechanism 62) is connected to each of the half mirrors 33 and 34. The position adjustment mechanism 60 allows the half mirrors 33 and 34 to be moved independently along the perpendicular line of the display surface of the display panel 20. In the above, the perpendicular line of the display surface can also be replaced with the optical axis 57.

[0054] As will be explained in more detail later, by moving the half-mirror 33 with the position adjustment mechanism 61, not only the light emitted from the surface of the eye 40 but also the light emitted from the retina 41 can be imaged onto the sub-pixel 23. In other words, the focal length of the reflecting and refraction optical system 30, including the eye 40, can be measured.

[0055] Furthermore, by moving the half-mirror 34 using the position adjustment mechanism 62 according to the measured focal length, the light emitted from the sub-pixels 22 can be focused onto the retina 41. In other words, the diopter can be automatically adjusted according to the user's visual acuity. Moreover, by moving the half-mirror 34 to a position where the image (virtual image) seen by the user appears further away, the ciliary muscle can be relaxed further, allowing for myopia improvement training.

[0056] In actual VR goggles, the display surface of the display panel 20 is positioned several tens of millimeters away from the surface of the eye 40. The user of the VR goggles does not directly view the display on the display panel 20, but rather views a virtual image magnified by the reflective and refractive optical system 30 positioned between the display panel 20 and the eye 40.

[0057] Figure 2A illustrates the position of the virtual image in a reflective-refracting optical system. Although actual reflective-refracting optical systems have complex optical paths, here they are simply described as a single lens. The display surface 20a of the display panel 20, which is the light source, is located between the front focal point F1 of the reflective-refracting optical system 30 and the reflective-refracting optical system 30. The eye 40 is located near the rear focal point F1' of the reflective-refracting optical system 30.

[0058] In Figure 2A, the position of the virtual image 20b is the intersection of the line (shown as a dashed line) extending to the left side of the reflective / refracting optical system 30 the optical path BM1 of light emitted from the display surface 20a, parallel to the optical axis 57 and proceeding to the rear focal point F1' of the reflective / refracting optical system 30, and the line (shown as a dashed line) extending to the left side of the reflective / refracting optical system 30 the optical path BM2 of light traveling from the display surface 20a to the center of the reflective / refracting optical system 30.

[0059] When X is the distance from the surface of the eye 40 to the display surface 20a, and Y is the distance from the surface of the eye 40 to the position of the virtual image 20b, the reflecting and refraction optical system 30 is usually designed so that X is 0.1 m or less, while Y is approximately 1.0 m to 2.0 m. In other words, when the user is focusing on the virtual image 20b, it can be said that they are looking at something approximately 1.0 m to 2.0 m away.

[0060] Thus, viewing images through VR goggles differs from viewing images through direct-view displays such as those found in smartphones, tablet computers, and laptop computers, as it involves viewing relatively distant objects. Therefore, VR goggles can be considered a device that makes it relatively easy to relax the ciliary muscle.

[0061] Here, we consider a case where a person with myopia cannot focus on a distant object with the naked eye, and can only focus up to position Z in Figure 2A (<Y: a position where the distance from the surface of the eye 40 is shorter than Y). In such a case, the focal length of the reflecting and refraction optical system 30 can be changed to adjust the virtual image 20b to appear at position Z or on the front focal point F1 side of position Z.

[0062] There are various ways to change the focal length of the reflecting / refracting optical system 30, such as changing the distance between lenses or adding an eyepiece. As will be described in detail later, in one aspect of the present invention, the focal length of the reflecting / refracting optical system 30 is changed by moving the half mirror 34.

[0063] Figure 2B shows the case where the focal lengths of the reflecting and refraction optical system 30 are changed to front focal point F2 and rear focal point F2', which are longer than the front focal point F1 and rear focal point F1' shown in Figure 2A. It can be seen that the virtual image 20b can be adjusted so that it appears, for example, on the front focal point F2 side of position Z. This adjustment, in which the virtual image is in focus according to the user's visual acuity, is called diopter adjustment.

[0064] In one embodiment of the present invention, after diopter adjustment, the focal length of the reflecting / refractive optical system 30 is readjusted so that the virtual image appears further away, within the range of focus. By viewing the virtual image at a further distance, the ciliary muscle becomes more easily relaxed.

[0065] In other words, by using VR goggles according to one aspect of the present invention, the user can perform training in a more relaxed state of the ciliary muscle without being conscious of it, thereby improving myopia. Furthermore, since the light-receiving element used for diopter adjustment also serves as an eye-tracking sensor, the number of components constituting the electronic device can be reduced, enabling miniaturization and cost reduction of the electronic device.

[0066] Next, the specific configuration of the reflecting and refraction optical system 30 will be described. Here, a configuration in which the polarization state in the optical path is controlled using a circular polarizer will be given as an example, but this is not the only configuration. For example, a configuration in which the polarization state is controlled using photorotators such as a Faraday rotator can also be used.

[0067] Figures 3 and 4 show a display panel 20 and a reflector / refractor optical system 30 of an electronic device. Figure 3 shows the optical path of visible light emitted by a sub-pixel 22 and reaching the eye 40. Figure 4 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 3 and 4 are examples only.

[0068] The reflective and refractive optical system 30 has a configuration in which a linear polarizer 31, a phase difference plate 32, a half mirror 33, 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, with the optical axis 57 passing 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.

[0069] Note that while Figures 3 and 4 show an example where the lens 51 is located between the reflective polarizer 36 and the eye 40, the system 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.

[0070] Furthermore, in Figures 3 and 4, 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] By using a reflective / refracting optical system 30 with this configuration, light emitted from the display panel 20, light emitted from the surface of the eye 40, or light emitted from the retina 41 can be converted into linearly polarized or circularly polarized light for use, allowing for selective reflection and transmission by elements arranged in 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.

[0078] Next, we will describe the details of each element of the display panel 20 and the reflecting / refracting optical system 30.

[0079] 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. ２The following light-emitting diodes are represented. Note that the LED panel is not limited to microLEDs; for example, a chip with a chip area of ​​10,000 μm² is also included. 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] For example, a dielectric multilayer film can be used for the half mirrors 33 and 34. Here, the half mirror 33 can be a dielectric multilayer film that transmits visible light and semi-transmits and semi-reflects infrared light. Similarly, the half mirror 34 can be a dielectric multilayer film that transmits infrared light and semi-transmits and semi-reflects visible light.

[0084] In a narrow sense, a half-mirror is a mirror with both reflectivity and transmittance of 50%, but the term "half-mirror" in this specification is not limited to this. In a reflective-refracting optical system, light has a path through which it passes through a half-mirror and then reflects. Therefore, the efficiency of light utilization is the product of reflectivity and transmittance, but since reflectivity + transmittance generally equals 1, if one of the reflectivity or transmittance decreases, the other increases. In other words, in a reflective-refracting optical system where light is used twice—once for reflection and once for transmission—the efficiency of light utilization does not change significantly even if both the reflectivity and transmittance deviate from 50%. Therefore, the reflectivity and transmittance of a half-mirror used in a reflective-refracting optical system are not limited to 50% in the wavelength range in which they are used, but can be, for example, 40% to 60%.

[0085] Figures 5A and 5B show the simulation results of spectral transmittance and spectral reflectance for a glass / dielectric multilayer film / air model when light is incident from the air side. Note that the dielectric multilayer film model is SiO ２ and TiO ２ The film consists of 26 layers stacked alternately, and Essential Macleod (manufactured by Thin Film Center Inc.) was used for the simulation software.

[0086] Examples of low refractive index materials that can be used in dielectric multilayer films include silicon oxide, silicon oxide nitride, magnesium fluoride, lithium fluoride, or sodium fluoride. High refractive index materials that can be used include titanium oxide, niobium oxide, silicon nitride, aluminum oxide, zirconium oxide, or hafnium oxide.

[0087] As shown in Figures 5A and 5B, it can be seen that a half-mirror can be formed that transmits visible light and semi-transmits and semi-reflects infrared light.

[0088] Although not shown in Figures 3 and 4, since the half-mirrors 33 and 34 are each extremely thin dielectric multilayer films, a support is required for their formation. The support material is preferably a material with high transmittance of visible light and infrared light, and glass or resin can be used.

[0089] Furthermore, because the support has a curved surface, curvature can be given to both the half mirror 33 and the half mirror 34, allowing them to be used as concave mirrors with positive power. Power refers to the light-gathering force; a positive power value concentrates light, while a negative power value causes light to diverge. The orientation and curvature of the concave surface can be appropriately set in combination with other elements of the reflecting and refraction optical system 30, and can be the same or different for the half mirror 33 and the half mirror 34.

[0090] For example, as shown in Figures 6A and 6B, the support 52 can have a shape in which the curvature of the convex and concave surfaces are the same, or a meniscus lens shape. In this case, the layer 70, which functions as a half-mirror, can be made to act as a concave mirror whether it is provided on the convex or concave surface.

[0091] Furthermore, as shown in Figure 6C, the support 52 can be shaped like a convex lens. In this case, by providing a layer 70 on the convex surface, it can function as a concave mirror. Although Figure 6C illustrates a plano-convex lens shape, a biconvex lens shape can also be used.

[0092] Furthermore, as shown in Figures 6D and 6E, the support 52 can be made into a concave lens shape. Although Figures 6D and 6E illustrate a biconcave lens shape, a plano-concave lens shape can also be used.

[0093] Furthermore, the half-mirror 33 may have multiple concave surfaces, for example, as shown in Figure 6F. By providing multiple concave surfaces in the half-mirror 33, there will be multiple imaging positions on the display panel. Therefore, multiple images can be obtained. In addition, since the sub-pixels 23 with imaging functions are not needed in the display panel except at the imaging positions, the degree of freedom in setting the positions where resolution is to be increased (arrangement of sub-pixels 22) can be increased.

[0094] Furthermore, the focal length can be determined not only by the power of the half-mirror acting as a concave mirror, but also by the combined effect of the power of the lens provided in the reflecting / refracting optical system 30. Therefore, in order to obtain a desired focal length, for example, as shown in Figures 6G and 6H, the layer 70 may be sandwiched between the support 52 and the support 53. In this case, the support 52 or the support 53 can be a plano-concave lens, a biconcave lens, a plano-convex lens, a biconvex lens, a convex meniscus lens, or a concave meniscus lens. The combination of support 52 and support 53 with different shapes has the following characteristics, and can be appropriately selected according to the purpose.

[0095] 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 support 52 and support 53 have the shape of a concave lens.

[0096] 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 support 52 and support 53 are a combination of a convex lens shape and a concave lens shape.

[0097] 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 support 52 and support 53 have the shape of a convex lens.

[0098] 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 considering that they are directly attached to the support 52 or support 53, a flat surface for adhesion is advantageous. Therefore, from the viewpoint of ease of manufacturing, it is preferable that one or more of the support 52 and support 53 have a flat surface on the outside.

[0099] Although Figures 6G and 6H illustrate the configuration of the support 52 shown in Figures 6A and 6B, the configurations of the support 52 shown in Figures 6C to 6E can also be applied.

[0100] 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.

[0101] 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. For example, a wire grid polarizer or a dielectric multilayer film can be used as the reflective polarizer 36. The reflective polarizer 36 is arranged 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 two optical paths between the display panel 20 and the eye 40.

[0102] For example, lens 51 can be a biconvex lens, a plano-convex lens, or a convex meniscus lens. Alternatively, lens 51 can be a combination of multiple lenses selected from biconvex lenses, plano-convex lenses, convex meniscus lenses, biconcave lenses, plano-concave lenses, and concave meniscus lenses. Furthermore, lens 51 is not limited to spherical lenses; it may also be an aspherical lens. By using a combination lens or an aspherical lens, various lens aberrations can be reduced.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] As the position adjustment mechanism 60, for example, a helicoid type, cylindrical cam type, rack and pinion type, slide rail type, or ball screw type mechanism can be used. Furthermore, a power source such as a stepping motor can be connected to each mechanism.

[0107] The position adjustment mechanism 60 allows the half mirrors 33 and 34 to be moved independently along the perpendicular line of the display surface of the display panel 20, enabling diopter adjustment and other adjustments described later.

[0108] Furthermore, diopter adjustment can also be made by moving the position of the lens 51. Therefore, a position adjustment mechanism 63 can be connected to the lens 51. If diopter adjustment can be sufficiently made by moving the half mirrors 33 and 34, the position adjustment mechanism 63 connected to the lens 51 may be unnecessary.

[0109] The position adjustment mechanism 60 is not directly connected to the half mirrors 33 and 34, but can be connected to the support of the half mirrors 33 and 34, or to a frame fixed to the support. In the case of the lens 51, the position adjustment mechanism 60 can be connected to a frame fixed to the lens 51.

[0110] Next, we will explain the optical path of the visible light emitted by the sub-pixel 22 shown in Figure 3.

[0111] Some of the light emitted from the sub-pixels 22 of the display panel 20 passes through the linear polarizer 31, the phase difference plate 32, and the half mirror 33, 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.

[0112] 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.

[0113] 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.

[0114] 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) passes through the half mirror 33, partially passes through the half mirror 34, and is 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.

[0115] 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.

[0116] Next, we will explain the optical path of infrared light emitted from the surface of the eye 40 shown in Figure 4.

[0117] 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. Here, the reflected light from the surface of the eye 40 is mainly described, but reflected light from the retina can be detected in the same way.

[0118] Furthermore, by acquiring images of the vicinity of the eye 40 with the sub-pixel 23, 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 the state of fatigue, and it is possible to determine the state of fatigue by detecting information related to blinking.

[0119] Furthermore, the light emitted by the light source 80 is preferably infrared light with low visual sensitivity that has little impact on visibility, and is preferably near-infrared light with relatively high energy (for example, light with a wavelength of 780 nm to 2 μm) due to the ease of photoelectric conversion by the photodetector. In addition, the light source 80 can be, for example, a light-emitting diode, and is not limited to one, but multiple can be used to irradiate the eye 40 from different directions.

[0120] Furthermore, it is preferable that the infrared light (IR) irradiated from the light source 80 to the eye 40 is linearly polarized and passes through the reflective polarizer 36. When unpolarized infrared light (IR) is irradiated to the eye 40, the amount of light transmitted through the reflective polarizer 36 is reduced to about 40% due to reflection and absorption. Considering the loss due to the half-mirror in the subsequent optical path, the amount of light reaching the sub-pixel 23 is about 10%, making it difficult to obtain a clear image. Increasing the amount of light emitted from the light source 80 will relatively increase the amount of light reaching the sub-pixel 23, but strong light irradiation may have adverse effects on the human body.

[0121] On the other hand, if the infrared light (IR) irradiated from the light source 80 to the eye 40 is linearly polarized and passes through the reflective polarizer 36, then the linearly polarized component of the light reflected by the eye 40 that passes through the reflective polarizer 36 can be transmitted 100% through the reflective polarizer 36. Considering the subsequent loss due to the half-mirror, the amount of light reaching the sub-pixel 23 is about 25%. In other words, if the amount of light irradiated from the light source 80 to the eye 40 is the same, it is easier to obtain a clearer image when using a specific linear polarization than when using unpolarized light. Note that the polarization state of the diffuse reflection component of linearly polarized light in the eye 40 may not be maintained, so it is preferable to adjust the incident angle from the light source 80 so that the specular reflection component is large.

[0122] Therefore, as shown in Figure 7A, it is preferable to provide a linear polarizer 81 between the light source 80 and the eye 40. For example, if the transmission axis of the reflective polarizer 36 is 90°, then the transmission axis of the linear polarizer 81 should also be 90°. Alternatively, as shown in Figure 7B, a mirror 55 may be placed between the light source 80 and the eye 40. By placing the mirror 55, the degree of freedom in the placement of the light source 80 can be increased. The placement of the linear polarizer 81 is not limited as long as it is on the optical path from the light source 80 to the eye 40. Also, as shown in Figures 7C and 7D, a reflective polarizer 36 can be used instead of the linear polarizer 81 by extending it to the vicinity of the placement of the light source 80. In this case, the support for the reflective polarizer 36 can be located on the optical path of the light emitted by the light source 80. Furthermore, as shown in Figure 7E, if a reflective polarizer 56 (here, with a reflection axis of 90°) is used instead of the mirror 55, the linear polarizer 81 can be made unnecessary.

[0123] 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, and half mirror 34, and is partially reflected by the half mirror 33. The light partially reflected by the half mirror 33 passes through the half mirror 34 and 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 the half mirror 34, partially passes through the half mirror 33, passes through the phase difference plate 32 and linear polarizer 31, and is imaged by the sub-pixel 23.

[0124] The details of the optical path, including the polarization state, will be explained further. In the following explanation, the light emitted from the surface of eye 40 will be assumed to be 90° linearly polarized.

[0125] 90° linearly polarized light emitted from the surface of the eye 40 passes through the lens 51 and the reflective polarizer 36 with a transmission axis of 90°, is incident on the phase difference plate 35 and converted to right circularly polarized light (R). The right circularly polarized light (R) passes through the half mirror 34 and is partially reflected by the half mirror 33, and its polarity is reversed to left circularly polarized light (L).

[0126] Left-circularly polarized light (L) passes through the half-mirror 34 and is incident on the phase difference plate 35, where it is converted to 0° linearly polarized light. The 0° linearly polarized light is reflected by the reflective polarizer 36 with a reflection axis of 0°, and is incident on the phase difference plate 35, where it is converted to left-circularly polarized light (L).

[0127] Left circularly polarized light (L) is transmitted through half mirror 34, partially transmitted through half mirror 33, and incident on phase difference plate 32, where it is converted to 0° linearly polarized light. The 0° linearly polarized light is transmitted through linear polarizer plate 31 with a transmission axis of 0° and incident on sub-pixel 23.

[0128] In this way, by utilizing linearly polarized and circularly polarized light, as well as half-mirrors and reflective polarizers, reflection and transmission can be selectively performed. Therefore, the optical path length can be secured within a limited space, and the focal length of optical instruments can be shortened.

[0129] Next, the operating modes of the electronic device of the present invention will be described using Figures 8A to 9B. In Figures 8A to 9B, elements other than the half-mirror are shown in an arrangement where they are close to each other, but the configuration is not limited to this. For example, these elements can be arranged independently, or they can be arranged in close proximity to the half-mirror or the support for the half-mirror. Also, although an example in which the position of the lens 51 is fixed is described here, it can also be moved in the same way as the half-mirror.

[0130] <Initial State> Figure 8A shows the initial state of the reflecting / refracting optical system 30. In electronic devices, the positional relationship between the display panel 20 and the eye 40 is fixed. Therefore, it is preferable that the initial state be one in which infrared light emitted by the light source 80 and reflected from the surface of the eye 40 is imaged by the sub-pixel 23 having a photoreceiving element, that is, a state in which eye tracking is possible.

[0131] Here, in a state where eye tracking is possible, the position of the half-mirror 33 that adjusts the path of infrared light is defined as position A. At this time, the electronic device can be said to be in its pre-use state, so it is not necessary for the user to be able to see the image clearly. Therefore, the initial position of the half-mirror 34 that adjusts the path of visible light can be any position B within the range of movement.

[0132] <Diopter Detection Mode> Figure 8B shows the state of the mode for detecting the user's diopter. When the user's eye 40 is in focus on the image (virtual image) on the display panel 20, the light emitted by the subpixel 22 is focused onto the retina of the eye 40 via the reflecting / refractive optical system 30. In other words, the focal point of the reflecting / refractive optical system 30, including the eye 40, is located on the retina.

[0133] This state can be said to have an optical path equivalent to the state in which light emitted from the retina 41 is imaged onto the sub-pixel 23 via the eye 40 and the reflecting / refractive optical system 30. Therefore, as shown in Figure 8B, by moving the half-mirror 33 so that the infrared light emitted from the light source 80 and reflected by the retina 41 is imaged onto the sub-pixel 23, the optical path can be set and the focal length of the reflecting / refractive optical system including the eye 40 can be measured.

[0134] The position of the half-mirror 33, which forms an image of infrared light reflected by the retina 41 at the sub-pixel 23, can be determined by the position where the intensity of infrared light received by the sub-pixel 23 is greatest after moving from position A, and this position is referred to as position C. Since position C differs depending on the user's diopter, the above operation can be called the diopter detection mode.

[0135] Furthermore, at this time, the half mirror 34 needs to be moved to a position other than position C so as not to interfere with the half mirror 33. Figure 8B shows an example where it is moved to position D, which is closer to the eye 40 than position B, but if there is no interference when the half mirror 33 is moved to position C, the half mirror 34 does not need to be moved from position B.

[0136] As mentioned above, Figure 8B is equivalent to the state in which the focal point of the reflective / refractive optical system 30, including the eye 40, is located on the retina. Therefore, if the half mirror 34 is located at or near position C, and within the range of the user's eye's accommodative power, the user can focus on the image. On the other hand, if the half mirror 34 is located far from position C, the user cannot focus on the image.

[0137] In this state, the eye 40 cannot focus on anything, causing the ciliary muscle to relax, which allows for diopter detection even when the eye 40 has low refractive power. Therefore, since the refractive power can be measured in a natural state for the eye 40, the accuracy of diopter detection can be improved.

[0138] <Image Viewing Mode> Figure 9A shows the mode in which the user views the image and the state in which eye tracking is possible. In image viewing mode, the half mirror 33 is moved from position C to position A. Also, the half mirror 34 is moved from position D to position C. By moving the half mirror 33 to position A, the same as the initial state, eye tracking becomes possible. Also, by moving the half mirror 34 to position C, the visible light emitted by the subpixel 23 can be imaged onto the retina 41. That is, the image can be viewed while reflecting the diopter adjustment.

[0139] <Vision Improvement Training Mode> Figure 9B shows a state in which a nearsighted user can perform vision improvement training while viewing an image, similar to the image viewing mode. In vision improvement training mode, the half mirror 34 is moved from position C to position E. Position E is the position in which the virtual image appears further away within the range in which the user can focus.

[0140] Position E varies depending on the user's eye's ability to adjust. In other words, the range in which the user's eye can focus cannot be physically measured, and feedback from the user who actually sees the image (virtual image) is necessary. If the position Z shown in Figures 2A and 2B is exceeded, focusing becomes impossible, and although it has the effect of relaxing the ciliary muscle, it loses its original function as an electronic device.

[0141] For example, the user can determine the position E by operating the position adjustment mechanism 62 and moving the half mirror 33 further away within the range where focus can be achieved.

[0142] Alternatively, the position adjustment mechanism 62 can be operated according to the information obtained by eye tracking. For example, while the user is viewing the image, the position adjustment mechanism 62 can gradually move the half mirror 33 from position C towards the display panel 20, detect the movement of the user's eyes and their vicinity, and repeatedly stop the movement or move it back slightly to determine position E.

[0143] When a person perceives difficulty in seeing an object they are trying to focus on, they perform some action around their eyes to adjust their focus. For example, they may unconsciously squint. Such actions are detected by eye tracking and fed back to the position adjustment mechanism 62. Furthermore, by using artificial intelligence that has learned the eye movements performed to adjust focus, the position E can be determined more accurately.

[0144] Alternatively, position E can be defined as the position obtained by moving the half-mirror 33 a certain amount from position C. The closest point at which the human eye can focus is the near point, and the farthest point is the far point; the area between the near and far points is called the clear vision range. The amount of accommodation that can be used to focus in the clear vision range varies from person to person, but the depth of field is said to be around 0.4D, and a difference of about 0.2D in distance from the object can be perceived as being in focus.

[0145] Therefore, by adjusting position E so that it is always 0.2D away from the virtual image position after diopter adjustment, it is possible to promote ciliary muscle relaxation without the user noticing a change in the virtual image position. Note that D is the symbol for diopter and is defined as the reciprocal of the focal length f (m). For example, if the virtual image position after diopter adjustment is 1D (1m), position E can be moved by a certain amount so that the virtual image appears at a position of 0.8D (1.25m).

[0146] Alternatively, as shown in Figure 10, instead of moving the half-mirror 34, a virtual image can be made to appear at or near the far point by, for example, changing the power of the lens 51. The power of the lens 51 can be changed by the user's own operation or by adjustment in accordance with information obtained from eye tracking.

[0147] In this case, the lens 51 can be an Alvarez lens, which can adjust the refractive power by sliding both of the two overlapping lenses; a lens whose shape can be changed by a liquid; a lens whose shape can be changed by pressure; a liquid crystal lens whose refractive power can be changed; or a Pancharatnam-Berry phase lens, which has a configuration in which optically anisotropic materials are appropriately arranged in two or three dimensions and can obtain a lens effect by causing a spatially geometric phase shift.

[0148] It should be noted that the above lens can also be used in another lens of the reflecting / refracting optical system, rather than lens 51.

[0149] In the above description, we explained a configuration in which two optical paths are formed using two half-mirrors with different characteristics. However, two optical paths can also be formed by using two reflective polarizers with different characteristics.

[0150] Figures 11 and 12 show examples of a reflective-refractive optical system 30 using two reflective polarizers with different characteristics. These differ from the configurations in Figures 3 and 4 in that half-mirrors 33 and 34 become one half-mirror 37, and reflective polarizer 36 becomes two reflective polarizers, 38 and 39. In the following explanation, the explanation of elements common to Figures 3 and 4 will be omitted.

[0151] The half-mirror 37 has semi-transmitting and semi-reflective properties in the range from visible light to infrared light. The reflective polarizer 38 has the properties of transmitting infrared light, reflecting 0° linearly polarized visible light, and transmitting 90° linearly polarized visible light. The reflective polarizer 39 has the properties of transmitting visible light, reflecting 0° linearly polarized infrared light, and transmitting 90° linearly polarized infrared light.

[0152] In other words, the reflective polarizer 38 adjusts the optical path of visible light, and the reflective polarizer 39 adjusts the optical path of infrared light. Therefore, the configurations shown in Figures 11 and 12 can perform the same operations as the configurations shown in Figures 3 and 4.

[0153] The reflective / refractive optical system 30 has a configuration in which a linear polarizer 31, a phase difference plate 32, a half mirror 37, a phase difference plate 35, a reflective polarizer 38, a reflective polarizer 39, and a lens 51 are arranged in this order in one direction from the display panel 20 side.

[0154] Furthermore, a position adjustment mechanism 65 (position adjustment mechanism 66, position adjustment mechanism 67) is connected to each of the reflective polarizing plates 38 and 39. The position adjustment mechanism 65 allows the reflective polarizing plates 38 and 39 to be moved independently along the perpendicular line to the display surface of the display panel 20. In the above, the perpendicular line to the display surface can also be replaced with the optical axis 57. Additionally, a position adjustment mechanism for moving the lens 51 may be connected as needed.

[0155] Next, we will explain the optical path of visible light emitted by the sub-pixel 22 shown in Figure 11.

[0156] Some of the light emitted from the sub-pixels 22 of the display panel 20 passes through the linear polarizer 31 and the phase difference plate 32, partially passes through the half mirror 37, passes through the phase difference plate 35, and is reflected by the reflective polarizer 36. The light reflected by the reflective polarizer 38 passes through the phase difference plate 35 and is partially reflected by the half mirror 37. The light partially reflected by the half mirror 37 passes through the phase difference plate 35, the reflective polarizer 38, the reflective polarizer 39 and the lens 51, enters the eye 40, and forms an image on the retina 41.

[0157] 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. When a liquid crystal panel is used for the display panel 20, the linear polarizer 31 can be used as one of a pair of polarizers in the liquid crystal panel.

[0158] 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 37 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.

[0159] The 0° linearly polarized light emitted from the phase difference plate 35 is reflected by the reflective polarizer 38 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 37, 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 with a transmission axis of 90°, the reflective polarizer 39 that transmits visible light, and the lens 51, and is incident on the eye 40.

[0160] Next, we will explain the optical path of infrared light emitted from the surface of the eye 40 shown in Figure 12.

[0161] 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 39, reflective polarizer 38, and phase difference plate 35, and is partially reflected by the half mirror 37. The light partially reflected by the half mirror 37 passes through the phase difference plate 35 and reflective polarizer 38, and is reflected by the reflective polarizer 39. The light reflected by the reflective polarizer 39 passes through the reflective polarizer 38 and phase difference plate 35, partially passes through the half mirror 37, passes through the phase difference plate 32 and linear polarizer 31, and is imaged by the sub-pixel 23. In the following description, the light emitted from the surface of the eye 40 is assumed to be 90° linearly polarized.

[0162] 90° linearly polarized light emitted from the surface of the eye 40 passes through the lens 51, the reflective polarizer 39 with a transmission axis of 90°, and the reflective polarizer 38 that transmits infrared light, and is incident on the phase difference plate 35 and converted to right circularly polarized light (R). The right circularly polarized light (R) is partially reflected by the half mirror 37 and its polarity is reversed to left circularly polarized light (L).

[0163] Left-circularly polarized light (L) is incident on the phase difference plate 35 and converted to 0° linearly polarized light, passes through the reflective polarizer plate 38, is reflected by the reflective polarizer plate 36 with a reflection axis of 0°, passes through the reflective polarizer plate 38, is incident on the phase difference plate 35 and converted to left-circularly polarized light (L).

[0164] Left-circularly polarized light (L) partially passes through the half-mirror 37 and is incident on the phase difference plate 32, where it is converted to 0° linearly polarized light. The 0° linearly polarized light passes through the linear polarizer plate 31 with a transmission axis of 0° and is incident on the sub-pixel 23.

[0165] Thus, two optical paths can be formed by using two reflective polarizers with different characteristics. Furthermore, two optical paths can also be established by swapping the positions of reflective polarizer 38 and reflective polarizer 39.

[0166] Figure 13A 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.

[0167] 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.

[0168] 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."

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] As shown in Figure 13B, 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 13B 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.

[0177] 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.

[0178] 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.

[0179] Figures 13C to 13E illustrate examples of sub-pixel layouts within a pixel 21. Figure 13A shows an example where one sub-pixel 22 and one sub-pixel 23 are placed within a pixel 21. However, as shown in Figure 13C, 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.

[0180] Note that while Figure 13C shows a layout in which sub-pixels 22R, 22G, 22B, and 23 are arranged vertically and horizontally, the layout shown in Figure 13D may also be used.

[0181] Furthermore, as shown in Figure 13E, 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.

[0182] Note that the arrangement of the subpixels shown in Figures 13C to 13E may be rearranged. Furthermore, the configuration of pixels and subpixels is not limited to those described above, and various arrangements can be adopted.

[0183] For example, as shown in Figures 14A and 14B, 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.

[0184] When pixels 21a and 21b are created in this manner, pixels 21a and 21b may be arranged alternately, as shown in Figure 14C. 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.

[0185] Alternatively, as shown in Figure 14D, 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.

[0186] Alternatively, as shown in Figure 15A, an aperture 59 that transmits visible light (VL) and partially transmits infrared light (IR) may be provided, and a configuration may be used that preferentially delivers light emitted from a part of the eye 40 to the sub-pixels 23. Since light that does not participate in imaging and arrives from various locations also reaches the sub-pixels 23, image blurring may occur. By providing the aperture 59, unwanted light can be blocked and light emitted from a part of the eye 40 can be preferentially delivered to the sub-pixels 23, thereby suppressing image blurring.

[0187] Figures 15B to 15G illustrate combinations of the pixel array 14 and the aperture 59. The aperture 59 can take on various forms, and as shown in Figure 14D, infrared (IR) light-transmitting regions 59T are provided according to the arrangement of regions 26 within the pixel array 14.

[0188] For example, as shown in Figure 15A, if the line connecting the eye 40 and the center of the display panel 20 coincides with the optical axis of the reflecting / refracting optical system 30, a transparent region 59T is provided near the center of the aperture 59, as shown in Figure 15B. In this case, the pixel array 14 should be provided with region 26 such that it has an area that overlaps with the transparent region 59T.

[0189] Furthermore, since the center of the display panel 20 is often within the central field of view, it is also effective to increase the resolution by placing a region 25 in the center of the display panel 20, as shown in Figure 14D. In this case, as shown in Figure 15C, a transparent region 59T should be provided outside the center of the aperture 59.

[0190] Furthermore, as shown in Figures 15D and 15E, the aperture 59 may have multiple transmission regions 59T. If the line connecting the eye 40 and the center of the display panel 20 does not coincide with the optical axis of the reflection / refractive optical system 30, an image off-center from the eye 40 will be captured. Therefore, as shown in Figures 15D and 15E, by having multiple transmission regions 59T and capturing images using the light transmitted through each, multiple images off-center from the eye 40 can be captured. By combining these multiple images, an image of the entire eye 40 can be obtained. When the aperture 59 has multiple transmission regions 59T, it is preferable to apply a configuration in which the concave surfaces of the half mirror 33 shown in Figure 6F are multiple (the same number as the transmission regions 59T).

[0191] Furthermore, as shown in Figures 15F and 15G, a region 25 may be provided near the center of the pixel array 14, and a region 27 on the outside of it may be provided in which pixels having only photoreceiving elements are arranged. Even if a light-emitting element is provided in a region outside the viewing angle of the electronic device, a person cannot see the display, but by adjusting the optical path, it is possible to image the eye 40 with the photoreceiving elements in that region. Therefore, in the pixel array 14, pixels having only photoreceiving elements can be provided in a region that is outside the viewing angle of the electronic device.

[0192] In Figures 15B to 15G, examples are shown where the shapes of region 25, region 26, and the transparent region 59T are circular or square, but they are not limited to these. For example, they may be elliptical or polygonal. Also, the sizes of region 25 and the transparent region 59T do not have to be the same. The aperture 59 can be formed by partially providing a dielectric multilayer film on a support that transmits visible light and infrared light.

[0193] 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.

[0194] Figure 16A 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.

[0195] 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.

[0196] 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.

[0197] 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.

[0198] Figure 16B 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.

[0199] 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.

[0200] 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.

[0201] Furthermore, as a modified version of circuit PIX2, circuit PIX3 shown in Figure 16C can also be used. Circuit PIX3 differs from circuit PIX2 in that it has a transistor M8 and a capacitor C3. In Figure 16C, elements common to both PIX2 and PIX3 are given the same reference numerals.

[0202] 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.

[0203] 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.

[0204] 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.

[0205] 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.

[0206] 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.

[0207] 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.

[0208] 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.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] 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.

[0214] OS transistors, which have a wider bandgap and lower carrier concentration than silicon transistors, 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.

[0215] 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.

[0216] Furthermore, the manufacturing cost of other transistors can also be reduced by using transistors that utilize oxide semiconductors in a similar manner.

[0217] 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.

[0218] 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.

[0219] Although Figures 16A to 16C illustrate an example using an n-channel transistor, a p-channel transistor can also be used.

[0220] Figure 17A shows an example of a goggle-type device according to one embodiment of the present invention. Here, the combination of the display panel 20 and the reflecting / refracting optical system 30 shown in Figure 3 or Figure 4 is shown as a display unit 99, indicated by a dashed line. Figure 17B also shows an example of a light source 80 provided inside the housing 90.

[0221] 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.

[0222] Two sets of display units 99 are incorporated into the housing 90. One display unit 99 is for the right eye, and the other is for the left eye. By displaying images corresponding to the parallax in each display unit 99, the user can perceive a sense of depth in the images.

[0223] Furthermore, the housing 90 or the holder 95 may be provided with input and output terminals. The input terminals can be connected to cables that supply video signals from video output devices, power for charging batteries, etc. The output terminals may function as, for example, audio output terminals, allowing the connection of earphones, headphones, etc. However, if the system is configured to output audio data via wireless communication, or if audio is output from an external video output device, such audio output terminals may not be necessary.

[0224] Furthermore, a wireless communication module and a storage module may be provided inside the housing 90 or the holder 95. The wireless communication module allows for wireless communication, enabling the download of content to be viewed and stored in the storage module. This allows the user to view the downloaded content not only online but also offline.

[0225] Furthermore, the light-receiving element and light source 80 of the display panel 20 can be made to function as a gaze detection sensor. The gaze detection sensor uses the light emitted from the light source 80 to detect the position of the gaze by reading the changes in reflected light caused by the movement of the pupil, iris, and white of the eye.

[0226] For example, changes in reflectivity caused by actions such as shifting the pupils to one side or one side vertically may be detected and assigned to the operation of electronic devices. For instance, operation buttons such as power on, power off, sleep, volume adjustment, channel change, menu display, selection, confirmation, and back, as well as operation buttons for video playback, stop, pause, fast forward, and rewind, can be displayed, allowing users to perform these operations by visually acknowledging the buttons. Furthermore, the system may detect the user's fatigue level based on the number of blinks and display an alert.

[0227] Furthermore, as mentioned above, the light-receiving element and light source 80 of the display panel 20 can detect the user's diopter, and the diopter can be adjusted automatically. In addition, after diopter adjustment, the position of the virtual image can be adjusted to appear further away within the range that the user can focus on, thereby enabling myopia improvement training. During this training, the user can view content that suits their preferences, which increases the likelihood of continued use and enhances the effectiveness of myopia improvement.

[0228] (Embodiment 2) This embodiment describes an example of the configuration of a display device that can be used as a display panel according to one aspect of the present invention.

[0229] In the display unit of a display device 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) for the light-emitting element. An MML structure 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 structure light-emitting element with a convex lens.

[0230] [Display Panel 200A] The display panel 200A shown in Figure 18 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 13C to 13E, 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 16A, 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 16B, respectively.

[0231] 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.

[0232] Furthermore, an element isolation layer 315 is provided between two adjacent transistors so as to be embedded in the substrate 301.

[0233] Furthermore, an insulating layer 261 is provided to cover the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0234] 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.

[0235] 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.

[0236] An insulating layer 255a is provided covering the capacitance 240, an insulating layer 255b is provided on the insulating layer 255a, and an insulating layer 255c is provided on the insulating layer 255b.

[0237] 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.

[0238] A light-emitting element 110R and a light-receiving element 110PD are provided on the insulating layer 255c.

[0239] 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.

[0240] The light-emitting element 110R includes a pixel electrode 111R, an organic layer 112R, a common layer 114, and a common electrode 113.

[0241] 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, an insulating layer 255c, a plug 256a embedded in the insulating layer 243, a conductive layer 241a embedded in the insulating layer 254, and a plug 271a embedded in the insulating layer 261.

[0242] 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.

[0243] 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.

[0244] 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 device can be made, and conversely, by making the pixel electrode reflective and the common electrode 113 transparent, a top-emission type display device can be made. Furthermore, by making both the pixel electrode and the common electrode 113 transparent, a dual-emission type display device can also be made.

[0245] 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.

[0246] 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.

[0247] 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.

[0248] 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 112 (also called step breakage), and to prevent the common electrode on the organic layer 112 from becoming insulated.

[0249] Furthermore, the resin layer 126 insulates the organic layers of adjacent light-emitting elements 110 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.

[0250] 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.

[0251] 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 112.

[0252] 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.

[0253] 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.

[0254] 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.

[0255] 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.

[0256] 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.

[0257] 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.

[0258] 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 110 has a certain degree of spread, any light that is not extracted to the outside of the display device is lost. Therefore, it is preferable for the display device to have high front brightness. Because the lens 102R has a convex lens shape, it can be made to focus the light. That is, it can suppress the divergence of light emitted by the light-emitting element, thereby increasing the light extraction efficiency of the display device.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] 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 devices.

[0264] In one aspect of the present invention, an organic EL element is used as the light-emitting element 110, 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 device using an organic EL element.

[0265] 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 manufacturing process of the display device can be reduced, and the reliability of the light-receiving element 110PD can be improved.

[0266] The light-receiving element 110PD has a pixel electrode 111PD, an organic layer 112PD, a common layer 114, and a common electrode 113.

[0267] 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, an insulating layer 255c, a plug 256b embedded in the insulating layer 243, a conductive layer 241c embedded in the insulating layer 254, and a plug 271b embedded in the insulating layer 261.

[0268] 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 manufacturing process of the display device and reduce the damage the active layer receives. 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.

[0269] 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.

[0270] 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.

[0271] An insulating layer 103 is provided on the common electrode 113, similar to the insulating layer 110R. A plano-convex lens 102PD is provided on the insulating layer 103 so as to overlap with the light-receiving element 110PD. A substrate 163 is provided on the lens 102PD via an insulating layer 104.

[0272] Since the lens 102PD has a convex shape, it can be made to focus light. Therefore, more light can be incident on the photodetector 110PD, thereby increasing the detection sensitivity of the photodetector 110PD.

[0273] [Display Panel 200B] The display panel 200B shown in Figure 19 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.

[0274] 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.

[0275] 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.

[0276] A plug 343 is provided on the substrate 301B, which 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.

[0277] 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.

[0278] 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.

[0279] 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).

[0280] [Display Panel 200C] The display panel 200C shown in Figure 20 has a configuration in which conductive layer 341 and conductive layer 342 are joined via bumps 347.

[0281] As shown in Figure 20, by providing a bump 347 between the conductive layer 341 and the conductive layer 342, the conductive layer 341 and the conductive layer 342 can be electrically connected. The bump 347 can be formed using a conductive material including, for example, gold (Au), nickel (Ni), indium (In), or tin (Sn). Alternatively, solder may 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.

[0282] [Display Panel 200D] The display panel 200D shown in Figure 21 differs from the display panel 200A mainly in its transistor configuration.

[0283] 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.

[0284] 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.

[0285] 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.

[0286] 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.

[0287] 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.

[0288] 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.

[0289] 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.

[0290] 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.

[0291] 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.

[0292] 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.

[0293] 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.

[0294] 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.

[0295] 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.

[0296] 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.

[0297] 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.

[0298] 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.

[0299] [Display Panel 200E] The display panel 200E shown in Figure 22 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.

[0300] 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.

[0301] 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.

[0302] 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.

[0303] [Display Panel 200F] The display panel 200F shown in Figure 23 is a configuration in which the transistor 320 of the display panel 200E shown in Figure 22 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 21.

[0304] Figure 24A shows a cross-sectional view of transistor 330 in the XZ plane. Figure 24B shows a cross-sectional view in the XY plane, including wiring 440.

[0305] 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.

[0306] 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.

[0307] 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.

[0308] 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.

[0309] As shown in Figure 24A, the oxide semiconductor 470 has a region 470i and regions 470na and 470nb that are provided so as to sandwich region 470i.

[0310] 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 24B, 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.

[0311] 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.

[0312] 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 24A 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.

[0313] 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.

[0314] 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.

[0315] 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.

[0316] 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 24B. 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 24A and 24B show the maximum width D of the opening 490 with a double-headed arrow. Figure 24B shows the channel width W of the transistor 330 with a double-headed arrow. By increasing the size of the maximum width D of the opening 490, the channel width per unit area can be increased, and the on-current can be increased.

[0317] 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".

[0318] 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.

[0319] Further, by forming the opening 490 so as to be substantially circular in top view, the oxide semiconductor 470, the insulator 430, and the conductor 420 are provided concentrically. Thereby, since the distance between the conductor 420 and the oxide semiconductor 470 becomes substantially uniform, a gate electric field can be applied to the oxide semiconductor 470 substantially uniformly.

[0320] The channel formation region of a transistor using an oxide semiconductor for the semiconductor layer preferably has less oxygen deficiency or a lower impurity concentration of hydrogen, nitrogen, metal elements, etc. than 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, even more preferably 1×10 ２０ atoms / cm ３ or less, even more preferably 5×10 １９ atoms / cm ３ or less, even more preferably 1×10 １９ atoms / cm ３ or less, even more preferably 5×10 １８ atoms / cm ３ or less, even more preferably 1×10 １８ atoms / cm ３ or less is even more preferable.

[0321] 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, the channel formation region of the transistor can be said to be i-type (intrinsic) or substantially i-type.

[0322] Further, the source region and the drain region of a transistor using an oxide semiconductor for the semiconductor layer have more oxygen deficiency 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.

[0323] In Figure 24A and other figures, the opening 490 is provided such that its side surface is perpendicular to the upper 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.

[0324] This embodiment can be implemented in appropriate combination with other embodiments and examples described herein, at least in part.

[0325] (Embodiment 3) This embodiment describes an indium oxide film that can be used in the semiconductor layer of a transistor in a display device according to one aspect of the present invention.

[0326] 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.

[0327] 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.

[0328] This paper describes the carrier concentration dependence of the hole mobility of indium oxide, silicon, and IGZO.

[0329] IGZO tends to exhibit higher hole mobility as the carrier concentration increases. On the other hand, single-crystal indium oxide tends to exhibit higher hole mobility as the carrier concentration decreases. This trend is similar to that of silicon, where lower dopant (impurity) concentrations in the material reduce impurity scattering and increase hole mobility. In other words, the higher the purity and intrinsic nature of single-crystal indium oxide, the higher its hole mobility. From these results, it can be said that single-crystal indium oxide, unlike IGZO, is a material with physical properties similar to silicon. Note that when indium oxide is not single-crystal (e.g., polycrystalline), the trend may differ from that of single crystals.

[0330] The range of carrier concentrations suitable for the channel formation region of a transistor is 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).

[0331] Indium oxide can contain elements that lower the carrier concentration. Examples of elements that lower the carrier concentration include magnesium, calcium, zinc, cadmium, and copper. These elements can lower the carrier concentration by substituting for indium. Other examples include nitrogen, phosphorus, arsenic, and antimony. These elements can lower the carrier concentration by substituting for oxygen.

[0332] On the other hand, electrical resistance can be reduced by increasing the carrier concentration. For example, the suitable carrier concentration range for the source and drain regions of a transistor, or for a resistor or transparent conductive film, 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 −３The 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.

[0333] Indium oxide 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.

[0334] Because indium oxide is an oxide whose valence electrons can be controlled, the region with a low carrier concentration can be used for the channel formation region of the transistor, and the region with a high carrier concentration can be used for the source and drain regions of the transistor. This makes it possible to create a so-called n-i-n junction (a junction between an n-type region, an i-type region, and an n-type region). Valence electron control in transistors using silicon is generally known. On the other hand, valence electron control in transistors using indium oxide is a novel technological concept that would not normally be conceived. By using this technological concept, it is possible to realize a transistor with high mobility, low off-current, normally-off capability, and high reliability.

[0335] The indium oxide film is preferably crystalline. In particular, the indium oxide film is preferably polycrystalline, and more preferably single-crystal. A single-crystal film does not have grain boundaries. By using a single-crystal film, carrier scattering at grain boundaries can be suppressed, enabling the realization of transistors that exhibit high field-effect mobility. Furthermore, it has the excellent effect of suppressing variations in transistor characteristics caused by these grain boundaries.

[0336] 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 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 a single-crystal film is applied.

[0337] 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 the analysis.

[0338] Furthermore, in this specification, a semiconductor layer in which no grain boundaries are observed in the channel formation region, a semiconductor layer in which the channel formation region is contained within a single crystal grain, or a semiconductor layer in which the crystal axis directions are the same in at least two regions within the channel formation region can be considered as a single crystal film.

[0339] The channel formation region refers to the region of 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 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.

[0340] Impurities in the indium oxide film can act as a source of carrier scattering, thus potentially causing a decrease in field-effect mobility and inhibiting crystal growth. Examples of impurities in the indium oxide film include gallium, zinc, boron, aluminum, and silicon. In the channel-forming region of the indium oxide film, lower concentrations of these impurities are preferable. For example, the concentration of each of the above impurity elements should be 0.1% or less, 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 greater amounts than the above impurities.

[0341] Furthermore, the indium oxide film 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.

[0342] 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.

[0343] One of the characteristics of indium oxide films is their higher oxygen permeability (diffusivity) compared to IGZO films. For example, oxygen diffusing into an indium oxide film permeates the film and is released as oxygen molecules. In some cases, it may also be released as water molecules by reacting with hydrogen contained in the film. Furthermore, if there is an oxygen deficiency in the film, diffusing oxygen atoms will fill the deficiency. Because oxygen diffuses easily through indium oxide films, it can be said that oxygen deficiencies are more easily filled in compared to IGZO films.

[0344] 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.

[0345] Furthermore, the indium oxide film diffuses hydrogen. Hydrogen diffusing into the indium oxide film from the outside permeates the film and is released as hydrogen molecules. Alternatively, it reacts with oxygen contained in the film and is released as water molecules.

[0346] 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 largely independent of the crystal orientation. Therefore, using crystalline indium oxide in transistors allows for the realization of transistors with high field-effect mobility and high frequency characteristics (also known as f-response). Moreover, due to the large effective hole mass, 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) at 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. Furthermore, because indium oxide has a smaller effective electron mass and a larger effective hole mass than silicon, it may be possible to realize transistors with higher field-effect mobility and lower off-current than Si transistors.

[0347] 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.

[0348] 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.

[0349] 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.

[0350] 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.

[0351] 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. YbFe２ O ４ Type structure or Yb ２ Fe ３ O ７ An example of a crystal having a type structure is IGZO.

[0352] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0353] 14: Pixel array, 15: Circuit, 16: Circuit, 17: Circuit, 18: Circuit, 19: Circuit, 20: Display panel, 20a: Display surface, 20b: Virtual image, 21: Pixel, 21a: Pixel, 21b: Pixel, 22: Sub-pixel, 22B: Sub-pixel, 22G: Sub-pixel, 22R: Sub-pixel, 22W: Sub-pixel, 23: Sub-pixel, 25: Region, 26: Region, 27: Region, 30: Reflective / refractive optical system, 31: Linear polarizer, 32: Phase difference plate, 33: Half mirror, 34: Half mirror, 35: Phase difference plate, 36: Reflective polarizer, 37: Half mirror, 38: Reflective polarizer, 39: Reflective polarizer, 40: Eye, 41 : Retina, 42: Pupil, 51: Lens, 52: Support, 53: Support, 55: Mirror, 56: Reflective polarizer, 57: Optical axis, 59: Aperture, 59T: Transmitting region, 60: Position adjustment mechanism, 61: Position adjustment mechanism, 62: Position adjustment mechanism, 63: Position adjustment mechanism, 65: Position adjustment mechanism, 66: Position adjustment mechanism, 67: Position adjustment mechanism, 70: Layer, 80: Light source, 81: Linear polarizer, 90: Housing, 95: Holder, 99: Display unit, 102PD: Lens, 102R: Lens, 103: Insulating layer, 104: Insulating layer, 110: Light-emitting element, 110PD: Photodetector, 110R: Light-emitting element Child, 111PD: Pixel electrode, 111R: Pixel electrode, 112: Organic layer, 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: Substrate, 200A: Display panel, 200B: Display panel, 200C: Display panel, 200D: Display panel, 200E: Display panel, 200F: Display panel, 240: Capacitance, 240a: Capacitance, 240b: Capacitance, 241: Conductive layer, 241a: Conductive layer, 241b: Conductive layer, 241c: Conductive layer, 243: Insulating layer, 245: Conductive layer, 2 45a: 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

1. An electronic device worn in front of the eye, comprising a display panel, a reflective / refracting optical system, and a light source, wherein the reflective / refracting optical system is positioned opposite the display surface of the display panel, the display panel has pixels having light-emitting elements and light-receiving elements, the light-emitting elements have the function of emitting visible light, the light-receiving elements have the function of converting infrared light into photoelectric energy, the reflective / refracting optical system comprises a first half-mirror, a second half-mirror, a first position adjustment mechanism, and a second position adjustment mechanism, the first half-mirror has the function of transmitting visible light and semi-transmitting / semi-reflecting infrared light, the second half-mirror has the function of transmitting infrared light and semi-transmitting / semi-reflecting visible light, the first position adjustment mechanism has the function of moving the first half-mirror along a perpendicular line to the display surface, and the second position adjustment mechanism has the function of moving the second half-mirror along a perpendicular line to the display surface. The light source is an electronic device having the function of emitting infrared light.

2. The electronic device according to claim 1, having a first function of moving the first half-mirror to a first position to image the infrared light reflected from the surface of the eye onto the photodetector, thereby imaging the eye and its vicinity; a second function of moving the first half-mirror to a second position to image the infrared light reflected from the retina of the eye onto the photodetector, thereby measuring the focal length of the reflecting and refraction optical system including the eye; and a third function of using the second function to determine the position to which the second half-mirror is moved, thereby imageing the visible light emitted by the light-emitting element onto the retina of the eye.

3. The electronic device according to claim 2, having a fourth function of moving the second half-mirror after the operation of the third function so that the virtual image on the display surface appears further away.

4. The electronic device according to claim 3, wherein the operation of the fourth function is performed using the first function.

5. The electronic device according to claim 1, wherein the reflective and refractive optical system is configured to have a linear polarizer, a first phase difference plate, one of the first half mirror and the second half mirror, the other of the first half mirror and the second half mirror, a second phase difference plate, and a reflective polarizer arranged in that order in one direction from the display panel side.

6. The electronic device according to claim 1, wherein the reflecting and refraction optical system comprises a lens and a third position adjustment mechanism, the third position adjustment mechanism having the function of moving the lens along a perpendicular line to the display surface.

7. The electronic device according to claim 6, wherein the first to third position adjustment mechanisms are of the helicoid type, cylindrical cam type, rack and pinion type, slide rail type, or ball screw type.

8. The electronic device according to claim 1, wherein the first half-mirror and the second half-mirror each have a concave surface.

9. The electronic device according to any one of claims 1 to 8, wherein 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.

10. The electronic device according to claim 9, wherein the metal oxide is indium oxide.

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