Electronic device

Abstract

Provided is an electronic device capable of obtaining dynamic information about an eye or the vicinity thereof. This VR device is capable of detecting dynamic information about an eye or the vicinity thereof and is provided with: a display unit that emits visible light; a light source unit that emits infrared light; a sensor unit that receives infrared light; and a catadioptric optical system. The catadioptric optical system enhances the utilization efficiency of infrared light by making the polarization states of visible light and infrared light different from each other. By using such a configuration, operation control or manipulations for the electronic device are performed by line-of-sight detection using infrared light. The light source unit and the sensor unit are provided in a display panel so that the miniaturization and cost reduction of the electronic device can be achieved.

Description

electronic equipment

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

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

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

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

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

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

[0007] Furthermore, in electronic devices for VR, infrared light sensors may be implemented to obtain dynamic information about the eyes or their vicinity, which is necessary for gaze detection and other purposes. For example, Patent Document 2 discloses an electronic device equipped with a sensor function that detects fatigue or abnormalities from blinking movements.

[0008] International Publication No. 2024 / 116029, International Publication No. 2022 / 234383

[0009] Sensors using infrared light, which has low visual sensitivity, are effective for detecting line of sight and information about the eyes and their vicinity. However, the increase in the number of components is contrary to the miniaturization, weight reduction, and cost reduction of electronic devices. Therefore, ingenuity in solving these problems is desired when integrating light sources and sensors into electronic devices.

[0010] Therefore, one aspect of the present invention aims to provide a low-cost, high-performance electronic device. Alternatively, it aims to provide an electronic device that can detect dynamic information from or near the user's eyes. Alternatively, it aims to provide an electronic device that can be operated by detecting the user's eye movements. Alternatively, it aims to provide an electronic device that places less strain on the body even during prolonged use. Alternatively, it aims to provide a novel display device. Alternatively, it aims to provide a novel electronic device. Alternatively, it aims to provide a novel semiconductor device, etc.

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

[0012] One aspect of the present invention is an electronic device to be worn in front of the eyes, which has a display panel and a refractive-reflective optical system. The refractive-reflective optical system is disposed between the display panel and the eyes. The display panel has a display unit, a light source unit, and a sensor unit. The refractive-reflective optical system has a half mirror and a reflective polarizing plate. A first optical path through which visible light emitted from the display unit reaches the eyes by reflection and transmission at the reflective polarizing plate and the half mirror, a second optical path through which infrared light emitted from the light source unit reaches the eyes by transmission at the half mirror and the reflective polarizing plate, and a third optical path through which infrared light reflected by the eyes enters the sensor unit by transmission at the reflective polarizing plate and the half mirror. It is an electronic device having.

[0013] The display panel has the display unit, the light source unit, and the sensor unit on the same plane, and the display unit can be located between the light source unit and the sensor unit.

[0014] The refractive-reflective optical system has, on the first optical path, a linear polarizing plate, a first retardation plate, a half mirror, a second retardation plate, and a reflective polarizing plate in this order from the display panel side, and on the second optical path, a linear polarizing plate, a third retardation plate, a half mirror, a second retardation plate, and a reflective polarizing plate in this order from the display panel side. The slow axes of the first retardation plate and the third retardation plate are orthogonal to each other.

[0015] The refractive-reflective optical system can have elements common to the second optical path on the third optical path. Alternatively, on the third optical path, a half mirror, a second retardation plate, and a reflective polarizing plate can be provided in this order from the display panel side.

[0016] The refractive-reflective optical system has, on the first optical path, a first linear polarizing plate, a first retardation plate, a half mirror, a second retardation plate, and a reflective polarizing plate in this order from the display panel side, and on the second optical path, a second linear polarizing plate, a first retardation plate, a half mirror, a second retardation plate, and a reflective polarizing plate in this order from the display panel side. The transmission axes of the first linear polarizing plate and the second linear polarizing plate are orthogonal to each other.

[0017] The refractive-reflective optical system can have elements common to the second optical path on the third optical path. Alternatively, a half mirror, a second retardation plate, and a reflective polarizing plate can be provided in this order from the display panel side.

[0018] The light source unit preferably has a plurality of light-emitting elements. Also, the sensor unit preferably has a plurality of light-receiving elements.

[0019] The light-emitting element of the display unit, the light-emitting element of the light source unit, and the light-receiving element of the sensor unit are each connected to a transistor, and the transistor can have a metal oxide in the channel formation region. The metal oxide is preferably indium oxide.

[0020] Another aspect of the present invention is an electronic device worn in front of the eyes, which has a display panel and a reflective refraction optical system. The reflective refraction optical system is disposed between the display panel and the eyes. The display panel has a first pixel having a first sub-pixel having a light-emitting element that emits visible light, a second sub-pixel having a light-emitting element that emits infrared light, and a third sub-pixel having a light-receiving element. The reflective refraction optical system has a half mirror and a reflective polarizing plate, and has a first optical path through which visible light reaches the eyes by reflection and transmission at the reflective polarizing plate and the half mirror, a second optical path through which infrared light reaches the eyes by transmission at the half mirror and the reflective polarizing plate, and a third optical path through which the infrared light reflected by the eyes enters the third sub-pixel by transmission at the reflective polarizing plate and the half mirror.

[0021] The reflective refraction optical system can have a linear polarizing plate, a liquid crystal panel, a half mirror, a second retardation plate, and a reflective polarizing plate on the first optical path, the second optical path, and the third optical path, from the display panel side.

[0022] The liquid crystal panel has a second pixel. The second pixel has a fourth sub-pixel having a region overlapping with the first sub-pixel and a fifth sub-pixel having a region overlapping with each of the second sub-pixel and the third sub-pixel, and can have a function of making the optical modulation of the respective liquid crystal elements of the fourth sub-pixel and the fifth sub-pixel different.

[0023] The light-emitting element of the first sub-pixel, the light-emitting element of the second sub-pixel, and the light-receiving element of the third sub-pixel are each connected to a transistor, and the transistor can have a metal oxide in the channel formation region. The metal oxide is preferably indium oxide.

[0024] Furthermore, an electronic device having a function to operate the electronic device by detecting eye movements is also one aspect of the present invention.

[0025] According to one aspect of the present invention, it is possible to provide a low-cost, high-performance electronic device. Alternatively, it is possible to provide an electronic device that can detect dynamic information from or near the user's eyes. Alternatively, it is possible to provide an electronic device that can be operated by detecting the user's eye movements. Alternatively, it is possible to provide an electronic device that places less strain on the body even during prolonged use. Alternatively, it is possible to provide a novel display device. Alternatively, it is possible to provide a novel electronic device. Alternatively, it is possible to provide a novel semiconductor device, etc.

[0026] 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.

[0027] Figure 1 is a diagram illustrating electronic equipment. Figures 2A, 2B, and 2C are diagrams illustrating optical elements. Figures 3A, 3B, and 3C are diagrams illustrating display panels. Figures 4A, 4B, 4C, 4D, 4E, 4F, and 4G are diagrams illustrating optical elements. Figures 5A, 5B, 5C, 5D, and 5E are diagrams illustrating optical elements. Figures 6A, 6B, 6C, and 6D are diagrams illustrating display panels. Figures 7A, 7B, and 7C are diagrams illustrating display panels. Figures 8A and 8B are diagrams illustrating display panels. Figures 9A, 9B, 9C, and 9D are diagrams illustrating display panels. Figures 10A and 10B are diagrams illustrating reflective and refractive optical systems. Figure 11 is a diagram illustrating the spectral transmittance and spectral reflectance of a half-mirror. Figures 12A, 12B, 12C, 12D, 12E, 12F, and 12G illustrate a half-mirror and support. Figures 13A and 13B illustrate a reflective-refracting optical system. Figures 14A and 14B illustrate a reflective-refracting optical system. Figures 15A and 15B illustrate the configuration of an electronic device. Figures 16A and 16B illustrate the configuration of an electronic device. Figures 17A and 17B illustrate the configuration of an electronic device. Figure 18 is an illustration of an electronic device. Figures 19A and 19B illustrate a reflective-refracting optical system. Figures 20A and 20B illustrate a liquid crystal panel. Figures 21A and 21B illustrate a reflective-refracting optical system. Figures 22A and 22B illustrate a liquid crystal panel. Figures 23A, 23B, and 23C illustrate a liquid crystal panel. Figures 24A, 24B, and 24C illustrate the operation of an electronic device. Figures 25A, 25B, and 25C illustrate the operation of an electronic device. Figures 26A, 26B, and 26C illustrate a display panel. Figures 27A, 27B, 27C, 27D, and 27E illustrate a display device. Figure 28A illustrates the pixel circuit. Figures 28B and 28C illustrate the circuit for driving a light-receiving element. Figure 29 is a perspective view illustrating a goggle-type electronic device. Figure 30A is a block diagram illustrating an electronic device.Figure 30B is a flowchart illustrating an example of the operation of an electronic device. Figure 31 is a diagram illustrating an example of the configuration of a display device. Figure 32 is a diagram illustrating an example of the configuration of a display device. Figure 33 is a diagram illustrating an example of the configuration of a display device. Figure 34 is a diagram illustrating an example of the configuration of a display device. Figure 35 is a diagram illustrating an example of the configuration of a display device. Figure 36 is a diagram illustrating an example of the configuration of a display device. Figures 37A and 37B are diagrams illustrating transistors.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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."

[0033] 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."

[0034] 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.

[0035] (Embodiment 1) This embodiment describes an electronic device according to one aspect of the present invention.

[0036] One aspect of the present invention is an electronic device for displaying an object worn in front of the eye, which is capable of detecting dynamic information in and around the eye. The display panel used in the electronic device includes, for example, a light source unit having a light-emitting device (also called a light-emitting element) on the outside of the display unit, and a sensor unit having a light-receiving device (also called a light-receiving element).

[0037] The display unit, light source unit, and sensor unit are mounted on the same circuit board, with the display unit positioned between the light source unit and the sensor unit. By using a display panel with this configuration, dynamic information from the eyes or their vicinity can be obtained, enabling control or operation of electronic devices through gaze detection. Furthermore, fatigue levels can be detected from the user's blinking movements, and the brightness, contrast, or color temperature of the electronic device's display can be adjusted according to the fatigue level. Therefore, it is possible to provide electronic devices that are easy to operate and put less strain on the body even during prolonged use.

[0038] Furthermore, since the light source and sensor are located within the display panel, there is no need to separately incorporate the light source and sensor as components of the electronic device. Therefore, the number of components constituting the electronic device can be reduced, enabling miniaturization and cost reduction of the electronic device.

[0039] Figure 1 is a perspective view illustrating a display panel and optical device that can be used in an electronic device according to one embodiment of the present invention. The electronic device according to one embodiment of the present invention is a display device worn in front of the eye, and Figure 1 also shows a schematic of the positional relationship between the display panel 20 and the user's eye 40. The normal line passing through the center C of the display unit 21 (display surface) is positioned such that it passes approximately through the center of the eye 40.

[0040] Specifically, the electronic equipment is VR equipment, and an optical device 30 for magnifying the display for viewing is provided between the display panel 20 and the eye 40. For clarity, the optical device 30 is shown here with a dashed line. The optical device 30 can be, for example, a reflective or refractive optical system, and further details will be described later.

[0041] The display panel 20 has a display unit 21, a light source unit 22, and a sensor unit 23 on the same substrate. For example, the display unit 21, the light source unit 22, and the sensor unit 23 can be provided on the same plane, and the display unit 21 can be provided between the light source unit 22 and the sensor unit 23. In other words, the light source unit 22 and the sensor unit 23 can be provided on the outside of the display unit 21, facing each other. By providing the light source unit 22 and the sensor unit 23 on the outside of the display unit 21 rather than inside it, the occupied area of ​​the display elements can be increased, and the display quality can be improved with high definition and high brightness.

[0042] Note that the positional relationship between the light source unit 22 and the sensor unit 23 is not limited to the illustrated example, and can be reversed. Also, the light source unit 22 and the sensor unit 23 are not limited to a single configuration, but can be configured with multiple units. That is, multiple light-emitting elements or light-receiving elements can be provided in the regions shown as the light source unit 22 and the sensor unit 23, respectively.

[0043] For example, an organic EL element emitting infrared light can be used as the light-emitting element in the light source unit 22, and a photoelectric conversion element with an organic layer as the active layer can be used as the light-receiving element in the sensor unit 23. Here, if organic EL elements are used for the pixels of the display unit 21 and a photoelectric conversion element with an organic layer as the active layer is used in the sensor unit 23, it becomes possible to form the organic EL elements, the organic EL elements of the light source unit 22, and the photoelectric conversion elements that act as light-receiving elements on the same substrate using a common process. Therefore, the manufacturing cost of the display panel and the component cost of the electronic device can be reduced.

[0044] The emitted light IRe from the light source unit 22 travels toward the eye 40 and reaches the eye 40 or its vicinity. Near the eye 40, a portion of the emitted light IRe is reflected as reflected light IRr and travels toward the sensor unit 23. In this way, the reflected light IRr reflected near the eye 40 can be detected by the sensor unit 23, and dynamic information about the eye 40 or its vicinity can be obtained by acquiring the change in the intensity of the reflected light IRr over time.

[0045] Specifically, because the position of the pupil, iris, and white of the eye (sclera) changes with the movement of the eye 40, the line of sight can be detected by reading the change in reflected light IRr. In addition, the number of blinks per unit time and the blinking speed can also be detected by reflected light IRr. The number and speed of blinks are also said to be related to the state of fatigue, so it is also possible to detect the state of fatigue by detecting information related to blinking.

[0046] Furthermore, it is preferable to use near-infrared light (for example, light with a wavelength of 780 nm to 2 μm) with relatively high energy, as the light emitted by the light source unit 22, which has little impact on the visibility of the display unit 21 and is relatively easy to convert into photoelectric power.

[0047] Although not shown in Figure 1, optical elements can also be provided on the light source unit 22 and the sensor unit 23 in order to efficiently direct the light emitted from the light source unit 22 toward the eye 40 and to efficiently direct the reflected light toward the sensor unit 23.

[0048] Figures 2A to 2C are schematic cross-sectional views of the light source unit 22 and the sensor unit 23 in the direction of the short axis, illustrating the form of the emitted light IRe emitted from the light source unit 22 and the form of the reflected light IRr reflected by the eye 40 and incident on the sensor unit 23. Although the figures show an example in which a layer 27 with high transmittance to infrared light is provided on the light source unit 22 and the sensor unit 23, there are also cases in which the layer 27 is not provided.

[0049] Figure 2A shows a configuration in which no optical elements are provided on the light source unit 22 and the sensor unit 23. When the light-emitting element of the light source unit 22 is an organic EL element or a light-emitting diode using an inorganic light-emitting layer, the emitted light IRe has relatively strong directivity, so this configuration can also be used. However, since the emitted light IRe has a certain degree of divergence angle, the light emitted in a direction different from the eye is not effectively utilized, and the reflected light IRr returning to the sensor unit 23 becomes weaker.

[0050] Therefore, it is preferable to provide, for example, convex lens-shaped optical elements 25L and 25S, as shown in Figure 2B, on the light source unit 22 and on the sensor unit 23, respectively. The optical element 25L can refract the emitted light IRe emitted from the light source unit 22 in an oblique direction, increasing the amount of light emitted in the forward direction (towards the eye 40). In addition, the reflected light IRr that is reflected by the eye 40 and returns to the vicinity of the sensor unit 23 can be focused onto the sensor unit 23 by the optical element 25S, so that information about the eye 40 and its vicinity can be obtained with high sensitivity.

[0051] Furthermore, prism-shaped optical elements 25L and 25S can be provided on the light source unit 22 and the sensor unit 23, respectively, as shown in Figure 2C. By adjusting the shape and orientation of the prism-shaped optical elements 25L and 25S, it is possible to make it easier to refract light in a desired direction.

[0052] Since the light reflected most strongly with respect to incident light is specular reflection, it is ideal that the angle of incidence of the emitted light IRe and the angle of reflection of the reflected light IRr with respect to the reflective surface (such as the eye 40) are equal. When the angle of incidence and the angle of reflection θ are equal, for example, the efficiency of light utilization can be increased by using prisms of the same shape as the optical element 25L provided on the light source unit 22 and the optical element 25S provided on the sensor unit 23, and arranging them symmetrically. In other words, information about the eye 40 and its vicinity can be obtained with high sensitivity.

[0053] Figures 2B and 2C show examples where the refractive indices of layer 27 and optical elements 25L and 25S are equivalent, and no significant refraction occurs at the interfaces between layer 27 and optical elements 25L and 25S.

[0054] Figure 3A is a top view of the display panel 20, showing enlarged views of the display unit 21, the light source unit 22, and the sensor unit 23.

[0055] The display unit 21 has a pixel PIX1, and each pixel PIX1 has a plurality of sub-pixels for display with different emission colors. Each sub-pixel is provided with a light-emitting element with a different emission color. Here, as an example of pixel PIX1, an S-stripe arrangement pixel having a sub-pixel R that emits red (R) light, a sub-pixel G that emits green (G) light, and a sub-pixel B that emits blue (B) light is given, but it is not limited to this. For example, a stripe arrangement, delta arrangement, zigzag arrangement, pentile arrangement, diamond arrangement, etc. can also be applied.

[0056] The light source unit 22 has a light-emitting element 22L. The sensor unit 23 has a light-receiving element 23S. As shown in Figure 3A, it is preferable that there be multiple light-emitting elements 22L in the light source unit 22 and multiple light-receiving elements 23S in the sensor unit 23. By having multiple light-emitting elements 22L and multiple light-receiving elements 23S and performing time-division control, detailed information such as eye movements or eyelid movements can be acquired in a time series. These details will be described later.

[0057] Furthermore, the light-emitting element 22L can be configured as a single element rather than multiple elements. In a single configuration, the area occupied by the light-emitting element 22L in the light source unit 22 can be increased, thereby increasing the amount of emitted light IRe. Similarly, the light-receiving element 23S can also be configured as a single element rather than multiple elements. In a single configuration, the area occupied by the light-receiving element 23S in the sensor unit 23 can be increased, thereby increasing the amount of reflected light IRr received.

[0058] The aforementioned optical elements can be provided on each of the light-emitting element 22L and the light-receiving element 23S. Note that Figure 3A shows an example where one optical element is provided on one light-emitting element or one light-receiving element, but this is not the only example. Multiple optical elements can be provided on one light-emitting element or one light-receiving element. Alternatively, one optical element can be provided on multiple light-emitting elements or multiple light-receiving elements.

[0059] As the optical element 25 (optical elements 25L, 25S), for example, a hemispherical convex lens or an aspherical convex lens as shown in Figure 4A can be used. Alternatively, a structure in which multiple convex lenses are coupled in one direction as shown in Figure 4B can be used. Alternatively, a lens array as shown in Figure 4C can be used. Alternatively, a cylindrical lens, a lens with a curved surface at the end of a cylindrical lens, or a configuration in which these are arranged in an array can be used as shown in Figures 4D to 4G.

[0060] Furthermore, as the optical element 25, for example, a triangular prism-shaped prism as shown in Figure 5A can be used. Alternatively, as shown in Figures 5B and 5C, a prism array having multiple triangular prisms for a single light-emitting element 22L or light-receiving element 23S can be used. Alternatively, as shown in Figure 5D, a configuration in which polyhedral prisms are arranged in an array can also be used.

[0061] Furthermore, when light is incident perpendicularly on one surface (plane) of the prism, the slanted surface, which is the light emission surface, contributes to refraction, allowing for a configuration with reduced thickness, similar to a Fresnel lens. For example, a polyhedron prism can be divided into multiple sections to reduce its thickness, as shown in Figure 5E. In order to significantly refract light with a prism, a large angle of incidence is necessary, which normally requires height (thickness). However, by dividing it into multiple sections to reduce the thickness, the overall thickness of the display panel 20 can be reduced.

[0062] Furthermore, it is also possible to use a lens-shaped optical element as described above for one of the optical elements 25L and 25S, and a prism-shaped optical element for the other.

[0063] The optical element 25 described above can be appropriately determined to maximize sensitivity for sensing reflected light from or near the eye, taking into consideration the shapes of the light-emitting and light-receiving elements to be combined, their positions within the display panel 20, the relative position of the object (such as an eye), and changes in the optical path due to the reflection-refractive optical system.

[0064] Note that while Figures 1 and 3A show examples where the light source unit 22 and sensor unit 23 are arranged so as to sandwich the display unit 21, the arrangement is not limited to this. For example, as shown in Figure 3B, one of the light source unit 22 or sensor unit 23 can be provided along the first edge of the display unit 21, and the other of the light source unit 22 or sensor unit 23 can be provided along the second edge perpendicular to the first edge.

[0065] Alternatively, as shown in Figure 3C, the light source unit 22 and the sensor unit 23 can be arranged along each of the sides of the display unit 21. Note that Figure 3C shows an example in which two light source units 22 and two sensor units 23 are arranged opposite each other, but it is not limited to this. It is also possible to have one light source unit 22 and three sensor units 23 on one side and three on the other. Alternatively, one light source unit 22 and two sensor units 23 can be arranged with one unit on the other, and the light source unit 22 and sensor units 23 can be arranged along each of the three sides of the display unit 21. By using such a configuration, the sensitivity of the sensor unit 23 can be improved.

[0066] Furthermore, as shown in Figure 6A, the display unit 21 may also have a pixel PIX2 that functions as a sensor unit 23. In addition to sub-pixels R, G, and B for display, the pixel PIX2 has a sub-pixel S that is equipped with a light-receiving element. In this case, a light source unit 22 can be provided outside the display unit 21. The configuration in Figure 6A has the function of a sensor unit 23 within the pixel, so it is possible to obtain information with high sensitivity and high resolution.

[0067] Alternatively, as shown in Figure 6B, the display unit 21 may have a pixel PIX 3 that functions as a light source unit 22. In addition to sub-pixels R, G, and B for display, the pixel PIX 3 has a sub-pixel L equipped with an infrared light-emitting element. In this case, a sensor unit 23 can be provided on the outside of the display unit 21. In the configuration of Figure 6A, since the light source unit 22 functions within the pixel, sufficient infrared light can be irradiated from the front, and the reflected light intensity can be increased. That is, the signal-to-noise ratio during sensing can be increased.

[0068] Furthermore, as shown in Figure 6C, the display unit 21 can also be divided into a region 21a that includes the center and a region 21b that is outside region 21a, with pixel PIX1 placed in region 21a and pixel PIX2 placed in region 21b. In this case, a light source unit 22 can be provided outside the display unit 21. Region 21b is a region where the resolution of the human eye is lower than that of region 21a. Therefore, pixel PIX2 can be placed over a large area outside the range where humans can perceive with high resolution, thereby increasing the signal-to-noise ratio during sensing without reducing display quality.

[0069] In Figure 6C, region 21a is shown as a circular shape that is the inscribed circle of the display unit 21, but the shape and size of region 21a are not limited to this. For example, region 21a can be a polygon such as an octagon. Also, region 21b can be a hollow, connected shape rather than being separated into the four corners of the display unit 21.

[0070] Alternatively, as shown in Figure 6D, pixel PIX1 can be placed in region 21a and pixel PIX3 in region 21b. In this case, a sensor unit 23 can be provided outside the display unit 21. Similar to the configuration in Figure 6C, region 21b is a region with lower visual resolution than region 21a. Therefore, pixel PIX3, which has the function of a light source unit 22, can be arranged over a wide area without reducing display quality within the range that humans can perceive with high resolution. This allows for sufficient infrared light irradiation and increases the reflected light intensity. In other words, the signal-to-noise ratio during sensing can be increased.

[0071] Furthermore, as shown in Figure 7A, the display unit 21 may also have a pixel PIX 4 that has the functions of the light source unit 22 and the sensor unit 23. In addition to sub-pixels R, G, and B for display, the pixel PIX 4 has a sub-pixel L provided with an infrared light-emitting element and a sub-pixel S provided with a light-receiving element.

[0072] Alternatively, as shown in Figure 7B, pixel PIX1 can be placed in region 21a and pixel PIX4 in region 21b.

[0073] Alternatively, as shown in Figure 7C, a donut-shaped region 21c can be provided between region 21a and region 21b, with pixel PIX1 placed in region 21a, pixel PIX3 in region 21b, and pixel PIX2 in region 21c. Alternatively, pixel PIX2 can be placed in region 21b and pixel PIX3 in region 21c.

[0074] In the configuration shown in Figures 7A to 7C, a separate light source unit 22 and sensor unit 23 can be eliminated outside the display unit 21, allowing the size of the display panel 20 to be reduced.

[0075] Alternatively, the display unit 21 may be configured with pixel PIX1, the light source unit 22 may be configured with pixel PIX_L having only an infrared light-emitting element, and the sensor unit 23 may be configured with pixel PIX_S having only a light-receiving element. In this case, for example, as shown in Figure 8A, the circular display unit 21 can be placed within a rectangular area, and the light source unit 22 and sensor unit 23 can be placed in multiple divided areas outside the display unit 21.

[0076] Furthermore, as shown in Figure 8B, a circular display unit 21, a hollow sensor unit 23 outside the display unit 21, and a light source unit 22 outside the sensor unit 23 can also be arranged within a rectangular area. The light source unit 22 can also be hollow. The positions of the sensor unit 23 and the light source unit 22 can also be swapped.

[0077] The configuration of the display panel 20 described in Figures 3A to 3C and 5A to 7B above can be appropriately determined to maximize the sensitivity for sensing reflected light from or near the eye, taking into consideration the relative position of the object (eye), changes in the optical path due to the reflecting and refraction optical system, etc.

[0078] In the configurations shown in Figures 8A and 8B, the areas of the light source unit 22 and the sensor unit 23 can be increased, thereby improving the signal-to-noise ratio during sensing. Furthermore, pixels PIX_L and PIX_S may share a common drive circuit with pixel PIX1. If the drive circuit is formed as a monolithic type, the area occupied by the drive circuit can be reduced, making it easier to incorporate circuits for other functions. Additionally, if the drive circuit is an external IC, the cost of the IC can be reduced.

[0079] Furthermore, in the display unit 21, in a configuration having pixels PIX1, PIX2, or PIX3, a configuration combining different pixels is also possible. For example, as shown in Figure 9A, pixels PIX1 and PIX2 (or PIX3) can be arranged in equal proportions. Alternatively, as shown in Figure 9B, pixels PIX2 (or PIX3) can be arranged in a ratio of 1 to 2 or more pixels PIX1. When the functions of the light source and sensor are sufficient, the display quality can be improved by using the above configuration.

[0080] Furthermore, in a configuration having PIX2 or PIX3, the arrangement of subpixels between adjacent pixels can be appropriately rearranged. For example, as shown in Figure 9C, by rearranging the arrangement of subpixels in four adjacent pixels PIX2, the subpixels S of each pixel can be integrated to form a single subpixel S with a larger area, thereby increasing the sensitivity of the sensing. The pixel circuit that drives the subpixel S can be provided in one of the four pixels PIX2, or it can be distributed among the four pixels PIX2.

[0081] Furthermore, as shown in Figure 9D, by rearranging the arrangement of subpixels in four adjacent pixels PIX3, the subpixels L of each pixel can be integrated to form a single subpixel L with a larger area, thereby increasing the amount of light irradiated to the eye. The pixel circuit that drives the subpixel L can be provided in one of the four pixels PIX3, or it can be distributed among the four pixels PIX3.

[0082] Next, a specific configuration of a reflecting / refracting optical system that can be used as optical instrument 30 will be described with reference to Figure 10A. Here, a configuration in which the polarization state in the optical path is controlled using a circular polarizer is given as an example, but it is not limited to this. For example, a configuration in which the polarization state is controlled using photorotators such as a Faraday rotator can also be used.

[0083] Figure 10A shows a display panel 20 and a reflective / refracting optical system 30, which are components of an electronic device. Note that the shapes and arrangements of the elements shown in Figure 10A are just examples.

[0084] Figure 10A also shows the optical path LP1 of visible light emitted from the display unit 21 of the display panel 20 and reaching the eye 40, and the optical path LP2 of infrared light emitted from the light source unit 22 and reaching the eye 40. The optical path LP3 of infrared light returning from the eye 40 to the sensor unit 23 will be described later.

[0085] The reflective-refracting optical system has a configuration in which a linear polarizer 31a, a phase difference plate 32a, 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 along the optical path LP1, and each is provided to have a region that overlaps with the optical axis 57 of the reflective-refracting optical system.

[0086] Furthermore, the reflective and refractive optical system has a configuration in which a linear polarizer 31a, a phase difference plate 32b, 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 along the optical path LP2.

[0087] In other words, in the configuration shown in Figure 10A, the phase difference plates 32 (phase difference plates 32a and 32b) differ between the elements on optical path LP1 and the elements on optical path LP2, while other elements can be common. Specifically, the phase difference plates 32a and 32b are arranged so that the orientation of their respective slow axes is orthogonal, causing the polarity of the circularly polarized light generated after transmission through the phase difference plates 32 to differ between optical path LP1 and optical path LP2.

[0088] As a result, the visible light in optical path LP1 can have a path that is reflected by the reflective polarizer 36, allowing the user to enlarge and view the image on the display panel 20. On the other hand, the infrared light in optical path LP2 can be transmitted without being reflected by the reflective polarizer 36, thereby increasing the efficiency of infrared light utilization.

[0089] A combination of a polarizer and a phase difference plate (linear polarizer 31a and phase difference plate 32a, linear polarizer 31a and phase difference plate 32b, phase difference plate 35 and reflective polarizer 36) is also called a circular polarizer, which converts unpolarized light into circularly polarized light.

[0090] In Figure 10A, an example is shown in which the linear polarizer 31a is common to both optical paths LP1 and LP2, but the phase difference plates 32 are different. However, the configuration is not limited to this. For example, as shown in Figure 10B, the phase difference plate 32a can be common, with the linear polarizer 31a placed on optical path LP1 and the linear polarizer 31b, whose transmission axis is perpendicular to that of the linear polarizer 31a, placed on optical path LP2. Even in such a configuration, the polarity of the circularly polarized light generated after transmission through the phase difference plate 32a can be made different in optical path LP1 and optical path LP2. Details of the polarization states in each optical path shown in Figures 10A and 10B will be described later.

[0091] Furthermore, Figure 10A shows an example where the lens 51 is located between the reflective polarizer 36 and the eye 40, but it is not limited to this. The lens 51 may be provided in other positions, or multiple lenses, including lens 51, may be provided. In addition, the lens 51, etc., can be used as a support for other elements of the reflective refractive optical system described above. By using the lens 51 as a support, the number of components of the optical system can be reduced.

[0092] Furthermore, in Figure 10A, the elements constituting the reflecting and refraction optical system 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 can be placed in close proximity. By placing adjacent elements in close proximity, the interface between the elements and the air can be reduced, which can prevent unwanted reflections.

[0093] 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.

[0094] 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. With such a configuration, properties equivalent to those of an optical contact can be obtained.

[0095] 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.

[0096] Furthermore, an anti-reflective layer can 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.

[0097] 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.

[0098] 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.

[0099] By using a reflective / refracting optical system with this configuration, the light emitted by the display panel 20 can be converted into linearly polarized or circularly polarized light for use, allowing for selective reflection and transmission by elements arranged along the optical path. Therefore, the optical path length can be secured within a limited space, and the optical device can be made more compact.

[0100] Next, we will describe the details of each element of the display panel 20 and the optical device 30.

[0101] As the display panel 20, a liquid crystal panel having liquid crystal elements, an organic EL panel having organic EL elements, or an LED panel having microLEDs can be used. In particular, it is preferable to use an organic EL panel, which is self-emissive and easy to form a high-definition display area. In this specification, a microLED refers to a chip with a chip area of ​​10,000 μm². ２ The following light-emitting diodes are represented. Note that the LED panel is not limited to microLEDs, but for example, a chip with a chip area of ​​10,000 μm². ２ Larger than 1 mm ２ The following light-emitting diodes (also called mini-LEDs) can also be used. If the image quality is acceptable, a larger pixel size can simplify the manufacturing process. In this embodiment, an example using an organic EL panel will be described.

[0102] The linear polarizer 31 can transmit one linearly polarized light from light (unpolarized) that vibrates in all 360° directions. For example, the linear polarizer 31 can be a thin film with uniaxially oriented iodine or dye, a wire grid polarizer, or a dielectric multilayer film. It is desirable to select a material that can convert both visible and infrared light into linearly polarized light.

[0103] In Figure 10A, the transmission axis of the linear polarizer 31 is assumed to be 0° for explanation purposes. However, 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.

[0104] The phase difference plates 32a and 32b have the function of converting linearly polarized light into circularly polarized light. Here, λ / 4 plates (quarter-wave plates) can be used for the phase difference plates 32a and 32b. 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 31a, right-rotating circularly polarized light (right-circular polarization) 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 31a, left-rotating circularly polarized light (left-circular polarization) is produced.

[0105] In one embodiment of the present invention, when λ / 4 plates are used for the phase difference plates 32a and 32b, they can be arranged so that the lagging axes are orthogonal, but the invention is not limited to this. For example, one of the phase difference plates 32a and 32b can be a λ / 4 plate, and the other can be a 3λ / 4 plate, so that the phase difference between the two is λ / 2.

[0106] In one aspect of the present invention, the lagging axes of the phase difference plates 32a and 32b are arranged orthogonally, so that the palpability of the circularly polarized light incident on the half mirror 34 differs between optical path LP1 and optical path LP2. In one aspect of the present invention, either right-circularly polarized or left-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. There is no difference in the efficiency of light utilization regardless of whether right-circularly polarized or left-circularly polarized light is used.

[0107] For example, a dielectric multilayer film can be used for the half mirror 34, which is made by alternately stacking films with relatively high and low refractive indices. In a narrow sense, a half mirror is a mirror with both reflectance and transmittance of 50%, but the half mirror in this specification is not limited to this. In a reflectance-refractive optical system of one aspect of the present invention, there is an optical path in which visible light passes through the half mirror and is then reflected by the half mirror. Therefore, the efficiency of light utilization is the product of reflectance and transmittance, but since reflectance + transmittance generally equals 1, if one of the reflectance or transmittance decreases, the other increases.

[0108] In other words, in a reflective-refracting optical system that uses light twice—once for reflection and once for transmission—the efficiency of light utilization does not change significantly even if both the reflectance and transmittance deviate from 50%. Therefore, the reflectance and transmittance of a half-mirror used in a reflective-refracting optical system for visible light are not limited to 50%, but can be, for example, 40% to 60%.

[0109] 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. Examples of high refractive index materials include titanium oxide, niobium oxide, silicon nitride, aluminum oxide, zirconium oxide, or hafnium oxide. Furthermore, to minimize optical loss, it is preferable to select materials with a small extinction coefficient for use in dielectric multilayer films.

[0110] Furthermore, in order to improve the utilization efficiency of the emitted light IRe emitted from the light source 22 and the reflected light IRr reflected by the eye 40, it is preferable that the half mirror 34 be configured to semi-transmit and semi-reflect visible light as described above, and transmit infrared light. By appropriately stacking the low refractive index material and the high refractive index material described above, for example, a half mirror that semi-transmits and semi-reflects visible light and transmits infrared light can be formed, as shown in Figure 11.

[0111] Figure 11 shows the simulation results, illustrating the spectral transmittance and spectral reflectance when light is incident from the air side for the glass / dielectric multilayer film / air model. The dielectric multilayer film model uses 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.

[0112] Although not shown in Figure 10A, the half-mirror 34 is an extremely thin multilayer film of dielectric or metal, and therefore requires a support for its formation. The support material is preferably one with high transmittance of visible and infrared light, and can be glass or resin.

[0113] Furthermore, because the support has a curved surface, each of the half-mirrors 34 can be given a curvature, allowing it to be used as a concave mirror with positive power. Power refers to the light-gathering force; a positive power value concentrates the light, while a negative power value causes the 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.

[0114] For example, as shown in Figures 12A and 12B, the support 52 of the half mirror 34 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 half mirror 34 can function as a concave mirror whether it is mounted on the convex or concave surface.

[0115] Furthermore, as shown in Figure 12C, the support 52 can be shaped like a convex lens. In this case, by providing a half-mirror 34 on the convex surface, it can function as a concave mirror. Although Figure 12C illustrates a plano-convex lens shape, a biconvex lens shape can also be used.

[0116] Furthermore, as shown in Figures 12D and 12E, the support 52 can be made into a concave lens shape. Although Figures 12D and 12E illustrate a biconcave lens shape, a plano-concave lens shape can also be used.

[0117] Furthermore, the focal length of a reflective-refracting optical system 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 reflective-refracting optical system. Therefore, to obtain a desired focal length, for example, as shown in Figures 12F and 12G, the half-mirror 34 can be sandwiched between supports 52 and 53. By attaching functional films such as phase difference plates and polarizing plates to the non-adhesive surfaces of the supports, the number of components can be reduced. Alternatively, the interface between the components and the air can be reduced, preventing unwanted reflections.

[0118] Supports 52 and 53 can be plano-concave, biconcave, plano-convex, biconvex, convex meniscus, or concave meniscus, and their shapes can be different. The shapes of the supports have the following characteristics and can be appropriately selected depending on the purpose.

[0119] 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.

[0120] 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 light is incident perpendicularly to that surface. 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.

[0121] 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 (concave mirror), the presence of a convex surface can further shorten the focal length. Therefore, in order to increase the positive power even slightly, it is preferable that one or more of the support 52 and support 53 have the shape of a convex lens.

[0122] In a reflective / refractive optical system as described in one aspect of the present invention, polarizers and phase difference plates are required. These are often 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.

[0123] Although Figures 12F and 12G illustrate the form of the support 52 shown in Figures 12A and 12B, the forms of the support 52 shown in Figures 12C to 12E can also be applied.

[0124] The phase difference plate 35 has the function of reversibly converting linearly polarized and circularly polarized light. Similar to the phase difference plates 32a and 32b, a λ / 4 plate (quarter-wave plate) can be used as the phase difference plate 35.

[0125] The reflective polarizer 36 can reflect linearly polarized light whose vibration direction coincides with its reflection axis, and transmit linearly polarized light perpendicular to its 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 31a. This arrangement allows for the establishment of optical paths LP1 and LP2.

[0126] 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.

[0127] For lenses used in reflective and refractive optical systems, it is desirable to use resin lenses to reduce weight. However, resins have a tendency to exhibit birefringence. In birefringent materials, the refractive index differs depending on the direction of polarization vibration, resulting in different transmission speeds for the polarization components. Therefore, after passing through the material, a phase difference occurs between the polarization components, causing a change in the polarization state. In reflective and refractive optical systems, a change in the polarization state results in light rays that do not follow the normal optical path. These light rays enter the eye as stray light and are perceived as double images or blurred images.

[0128] 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.

[0129] 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.

[0130] Next, we will explain the optical path LP1 of visible light emitted by the display unit 21 shown in Figure 10A.

[0131] A portion of the light (visible light VL) emitted from the display section 21 of the display panel 20 passes through the linear polarizer 31a and the phase difference plate 32a, 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, and is incident on the eye 40.

[0132] In this way, by repeatedly reflecting within a reflective / refracting optical system, the optical path length can be secured, making it possible to create an optical system with a short focal length.

[0133] The details of the optical path, including the polarization state, will now be explained. Visible light (unpolarized) vibrating in all 360° directions emitted from the display panel 20 is incident on the linear polarizer 31a. The transmission axis of the linear polarizer 31a is 0°, and 0° linearly polarized light is emitted from the linear polarizer 31a. If a liquid crystal panel is used for the display panel 20, the linear polarizer 31a can be used as one of a pair of polarizers in the liquid crystal panel.

[0134] The 0° linearly polarized light emitted from the linear polarizer 31a is converted to left-circularly polarized light (L) by the phase difference plate 32a. The left-circularly polarized light (L) is partially transmitted through the half mirror 34 and incident on the phase difference plate 35, where it is converted back to 0° linearly polarized light. Here, we describe an example where the light emitted from the phase difference plate 32a is left-circularly polarized, but it can also be right-circularly polarized.

[0135] 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.

[0136] Next, we will explain the optical path LP2 of the infrared light (emitted light IRe) emitted by the light source unit 22 shown in Figure 10A.

[0137] A portion of the light emitted from the light source unit 22 of the display panel 20 passes through the linear polarizer 31a, phase difference plate 32a, half mirror 34, phase difference plate 35, reflective polarizer 36, and lens 51, and is incident on the eye 40. In the optical path LP2, infrared light passes through the half mirror 34 and uses a different polarization state than visible light, so it does not reflect off the reflective polarizer 36. Therefore, the efficiency of light utilization can be increased without significant attenuation.

[0138] In the optical path LP1, there is a path through which the light is reflected after passing through the half mirror 34, and the light is attenuated twice by the half mirror 34. Therefore, if the transmittance of the linear polarizer 31a is 40%, the transmittance (reflectance) of the half mirror 34 for visible light is 50%, and the transmittance of the other elements is 100%, then if the amount of light emitted from the display unit 21 is 1, then the amount of visible light reaching the eye 40 is 1 × 0.4 × 0.5 × 0.5 = 0.1.

[0139] On the other hand, since the half mirror 34 has a transmittance of 100% for infrared light, if the amount of light emitted from the light source 22 in the optical path LP2 is 1, then the amount of visible light reaching the eye 40 is 1 × 0.4 = 0.4. In other words, while the light utilization efficiency in the optical path LP1 is 10%, the light utilization efficiency in the optical path LP2 can be increased to 40%, thereby improving the sensitivity of infrared light sensing. Note that the above values ​​are ideal values ​​that do not take into account attenuation due to unintended absorption and reflection in each element along the optical path.

[0140] Next, we will explain the details of the optical path with added polarization. Infrared light (unpolarized) vibrating in all 360° directions emitted from the display panel 20 is incident on the linear polarizer 31a. The transmission axis of the linear polarizer 31a is 0°, and 0° linearly polarized light is emitted from the linear polarizer 31a.

[0141] The 0° linearly polarized light emitted from the linear polarizer 31a is converted to right-circularly polarized light (R) by the phase difference plate 32b. The right-circularly polarized light (R) passes through the half mirror 34 and is incident on the phase difference plate 35, where it is converted to 90° linearly polarized light. The 90° linearly polarized light emitted from the phase difference plate 35 passes through the reflective polarizer 36 and lens 51 with a transmission axis of 90° and is incident on the eye 40. Note that here we describe an example where the light emitted from the phase difference plate 32b is right-circularly polarized, but it can also be left-circularly polarized.

[0142] In the configuration shown in Figure 10B, the optical path LP1 is the same as in Figure 10A, and the optical path LP2 is as follows.

[0143] Infrared light (unpolarized) vibrating in all 360° directions emitted from the display panel 20 is incident on the linear polarizer 31b. The transmission axis of the linear polarizer 31a is 90°, and 90° linearly polarized light is emitted from the linear polarizer 31b.

[0144] The 90° linearly polarized light emitted from the linear polarizer 31b is converted to right-circularly polarized light (R) by the phase difference plate 32a. The right-circularly polarized light (R) passes through the half mirror 34 and is incident on the phase difference plate 35, where it is converted to 90° linearly polarized light. The 90° linearly polarized light emitted from the phase difference plate 35 passes through the reflective polarizer 36 and lens 51 with a transmission axis of 90° and is incident on the eye 40.

[0145] In other words, similar to the configuration in Figure 10A, the only element that significantly attenuates light on the optical path LP2 is the linear polarizer 31a, thus increasing the efficiency of light utilization.

[0146] Next, we will describe the optical path LP3 of the infrared light that is reflected by the eye 40 and returns to the sensor unit 23. Figure 13A is a diagram showing the configuration of Figure 10A with the addition of the optical path LP3 of the infrared light (reflected light IRr) reflected by the eye 40. Note that the elements on the optical path LP3 can be the same as the elements on the optical path LP2.

[0147] A portion of the reflected light IRr reflected by the eye 40 passes through the lens 51, the reflective polarizer 36, the phase difference plate 35, the half mirror 34, the phase difference plate 32b, and the linear polarizer 31a, and is incident on the sensor unit 23. In this way, all elements within the reflective-refracting optical system can be transmitted, and similar to the optical path LP2, the efficiency of light utilization can be increased.

[0148] The infrared light reflected by the eye 40 (90° linearly polarized light that has been specularly reflected) passes through the lens 51 and the reflective polarizer with a transmission axis of 90°, and is converted to right-circularly polarized light (R) by the phase difference plate 35. The right-circularly polarized light (R) passes through the half mirror 34 and is incident on the phase difference plate 32b, where it is converted to 0° linearly polarized light. The 0° linearly polarized light emitted from the phase difference plate 32b passes through the linear polarizer 31a with a transmission axis of 0° and is incident on the sensor unit 23.

[0149] Of the 90° linearly polarized light incident on the eye 40 in the optical path LP2, the specular reflection component maintains its 90° linear polarization, while the diffuse reflection component is prone to changes in polarization state. Therefore, since the specular reflection component, which strongly reflects the state of the eye 40, becomes the main component transmitted through the reflective polarizer 36, the state of the eye 40 (line of sight, blinking, etc.) can be detected more accurately.

[0150] Furthermore, some elements on the optical path LP3 can be omitted. For example, as shown in Figure 13B, the linear polarizer 31a and the phase difference plate 32a (circular polarizer) are not provided on the optical path LP3, allowing the light to be incident on the sensor unit 23 in a circularly polarized state.

[0151] In this configuration, unintended reflection and absorption by the circular polarizer are avoided, which may increase the efficiency of light utilization. On the other hand, stray light may increase because the possibility of unintended polarization components generated within the reflective / refracting optical system being absorbed by the circular polarizer is eliminated. The presence or absence of the circular polarizer can be appropriately determined by considering these advantages, disadvantages, and manufacturing difficulties.

[0152] Figure 14A shows the configuration of Figure 10B with the addition of the optical path LP3 for infrared light (reflected light IRr) reflected by the eye 40. Note that the elements on optical path LP3 can be the same as the elements on optical path LP2.

[0153] A portion of the reflected light IRr reflected by the eye 40 passes through the lens 51, the reflective polarizer 36, the phase difference plate 35, the half mirror 34, the phase difference plate 32a, and the linear polarizer 31b, and is incident on the sensor unit 23. In this way, all elements within the reflective and refractive optical system can be transmitted, and similar to the optical path LP2, the efficiency of light utilization can be increased.

[0154] The infrared light (90° linearly polarized) reflected by the eye 40 passes through the lens 51 and a reflective polarizer with a transmission axis of 90°, and is converted to right-circularly polarized light (R) by the phase difference plate 35. The right-circularly polarized light (R) passes through the half mirror 34 and is incident on the phase difference plate 32a, where it is converted to 90° linearly polarized light. The 90° linearly polarized light emitted from the phase difference plate 32a passes through the linear polarizer 31b with a transmission axis of 90° and is incident on the sensor unit 23.

[0155] Furthermore, some elements on the optical path LP3 can be omitted. For example, as shown in Figure 14B, the optical path LP3 can be configured without a linear polarizer 31b and a phase difference plate 32a (circular polarizer), allowing the light to be incident on the sensor unit 23 in a circularly polarized state.

[0156] Next, the specific arrangement of the linear polarizing plates 31a, 31b, phase difference plates 32a, 32b, half mirror 34, phase difference plate 35, and reflective polarizing plate 36 will be described.

[0157] Figure 15A shows the arrangement according to Figures 10A and 13A, where a linear polarizing plate 31a is provided on a substrate 20g facing the substrate on which the display unit 21 and other components of the display panel 20 are provided, and a phase difference plate 32b is provided on the linear polarizing plate 31a. The linear polarizing plate 31a can be provided so as to have regions that overlap with the display unit 21, the light source unit 22, and the sensor unit 23, respectively. The phase difference plate 32b can also be provided so as to have regions that overlap with the light source unit 22 and regions that overlap with the sensor unit 23, respectively.

[0158] The phase difference plate 32a can be mounted on a plano-convex lens 51 that is spaced apart from the display panel 20. When the lens 51 is mounted in this position, it is preferable to mount the lens 51 in an area that does not become part of the optical paths LP2 and LP3 so as not to obstruct the paths of the optical paths LP2 and LP3.

[0159] The lens 51 may also be provided in other positions. If the lens 51 is provided in other positions, the phase difference plate 32a can be provided using a flat support. Alternatively, the phase difference plate 32a can be provided on the linear polarizing plate 31a. The phase difference plate 32a can be provided so as to have an area that overlaps with the display unit 21 and the sensor unit 23.

[0160] Alternatively, as shown in Figure 16A, the linear polarizing plate 31a can be divided and the linear polarizing plate 31a can be placed on the phase difference plate 32a on the lens 51.

[0161] The half-mirror 34 can be provided on the curved side of a plano-convex lens-shaped support 54, which is provided at a distance from the lens 51. By arranging it so that the curved surface faces the display panel 20, the half-mirror 34 can act as a concave mirror that focuses light toward the eye 40. The phase difference plate 35 can be provided, for example, on the plane opposite to the curved side of the support 54. The reflective polarizing plate 36 can be provided on the phase difference plate 35.

[0162] Furthermore, the arrangement of the linear polarizers 31a, 31b and the phase difference plates 32a, 32b can also be as shown in Figure 15B. The arrangement of the half mirror 34, phase difference plate 35, and reflective polarizer 36 can be the same as shown in Figure 15A.

[0163] Figure 15B shows the arrangement according to Figures 10A and 13B. The configuration shown in Figure 15B can be obtained by omitting the linear polarizing plate 31a and the phase difference plate 32b, which have a region overlapping with the sensor unit 23, from the configuration shown in Figure 15A. Alternatively, as shown in Figure 16B, the linear polarizing plate 31a can be divided and the linear polarizing plate 31a can be placed on the phase difference plate 32a on the lens 51.

[0164] Furthermore, the arrangement of the linear polarizing plates 31a, 31b and the phase difference plates 32a, 32b can also be as shown in Figure 17A.

[0165] Figure 17A shows the arrangement according to Figures 10B and 14A, with linear polarizing plates 31a and 31b provided on the substrate 20g. Linear polarizing plate 31a can be provided so as to have a region that overlaps with the display unit 21. Linear polarizing plate 31b can also be provided so as to have a region that overlaps with the light source unit 22 and a region that overlaps with the sensor unit 23.

[0166] The phase difference plate 32a can be provided on the lens 51, which is provided at a distance from the display panel 20, or on the linear polarizing plate 31b, respectively. The phase difference plate 32a can be provided so as to have an area that overlaps with the display unit 21, the light source unit 22, and the sensor unit 23. Alternatively, the phase difference plate 32a can be provided on the linear polarizing plate 31a instead of on the lens 51.

[0167] Furthermore, the arrangement of the linear polarizing plates 31a, 31b and the phase difference plates 32a, 32b can also be as shown in Figure 16B.

[0168] Figure 17B shows a configuration according to Figures 10B and 14B. The configuration shown in Figure 17B can be obtained by omitting the linear polarizing plate 31b and the phase difference plate 32a, which have regions that overlap with the sensor unit 23, from the configuration shown in Figure 17A.

[0169] Next, we will describe the case in which a display panel 20 having pixels PIX4 as shown in Figures 7A and 7B is used. Each pixel PIX4 has a sub-pixel L that functions as a light source unit 22 and a sub-pixel S that functions as a sensor unit 23.

[0170] Figure 18 is a perspective view illustrating a display panel 20 and optical equipment 30 having pixels PIX4. In the display panel 20 having pixels PIX4, the size of the sub-pixels L corresponding to the light source unit 22 and the sub-pixels S corresponding to the sensor unit 23 becomes very small, making it extremely difficult to arrange different linear polarizers or different phase difference plates for each sub-pixel.

[0171] Therefore, as shown in Figure 18, it is preferable to use a liquid crystal panel 29 that functions as a phase difference plate as one of the elements of the optical device 30, and to control the transmitted circular polarization for each sub-pixel. The liquid crystal panel 29 has pixels PIX_LC, and each pixel PIX_LC has sub-pixels LC1 and LC2.

[0172] Sub-pixel LC1 has regions that overlap with sub-pixels R, G, and B of pixel PIX4, respectively. Sub-pixel LC2 has regions that overlap with sub-pixels L and S of pixel PIX4, respectively. Sub-pixel LC2 can generate a phase difference in incident light, similar to a phase difference plate, through optical modulation of the liquid crystal element.

[0173] Figure 19A shows an example of the arrangement of elements of the reflective / refracting optical system, which is the display panel 20 and optical device 30 shown in Figure 18, as well as the optical path LP1 of visible light VL emitted from sub-pixel R and the optical path LP2 of emitted light IRE emitted from sub-pixel L. The change in polarization state in optical paths LP1 and LP2 is the same as in Figure 10A, and the liquid crystal panel 29 performs the functions of phase difference plates 32a and 32b.

[0174] The reflective-refracting optical system has a configuration in which a linear polarizer 31a, a liquid crystal panel 29, a half mirror 34, a phase difference plate 35, a reflective polarizer 36, and a lens 51 are arranged in this order in one direction from the display panel 20 side, and each is provided to have a region that overlaps with the optical axis 57 of the reflective-refracting optical system.

[0175] Furthermore, Figure 19B is a diagram of Figure 19A with the optical path LP3 added. The change in polarization state in the optical path LP3 is the same as in Figure 13A, and the liquid crystal panel 29 takes on the functions of the phase difference plates 32a and 32b.

[0176] The configuration of the liquid crystal panel 29 and the method of generating circularly polarized light of different magnitudes by creating a phase difference using the liquid crystal panel 29 will be explained with reference to Figures 20A and 20B.

[0177] Figures 20A and 20B show schematic cross-sectional views of the pixel PIX 4 and the liquid crystal panel 29. The pixel PIX 4 shows sub-pixel R, which is one of the sub-pixels that functions as a display unit 21; sub-pixel L, which functions as a light source unit 22; and sub-pixel S, which functions as a sensor unit 23. The liquid crystal panel 29 shows, for example, sub-pixel LC1, which functions as a phase difference plate 32a; and sub-pixel LC2, which functions as a phase difference plate 32b. A linear polarizing plate 31a is provided between the pixel PIX 4 (display panel 20) and the liquid crystal panel 29.

[0178] Figure 20A shows the off state in which no electric field is applied between the electrodes of the liquid crystal elements (pixel electrode / liquid crystal / common electrode) for both sub-pixel LC1 and sub-pixel LC2. In this state, both sub-pixel LC1 and sub-pixel LC2 behave the same way, so it is not possible to generate circularly polarized light of different polarities from the light emitted from pixel PIX4.

[0179] Note that while Figure 20A illustrates a liquid crystal element in the longitudinal electric field mode where the substrate on which the pixel electrodes are provided and the substrate on which the common electrode is provided face each other, the invention is not limited to this. For example, a liquid crystal element in the transverse electric field mode where the pixel electrodes and the common electrode are provided on the same substrate can also be used.

[0180] Figure 20B shows sub-pixel LC1 in the off state and sub-pixel LC2 in the on state, where an electric field is applied to the liquid crystal element. Here, the phase modulation due to the orientation of liquid crystal molecules in the off state is λ / 4, and the phase modulation due to the orientation of liquid crystal molecules in the on state is -λ / 4. That is, sub-pixel LC1 in the off state and sub-pixel LC2 in the on state can be made to function in the same way as phase difference plates 32a and 32b, whose slow axis is orthogonal.

[0181] When unpolarized visible light VL emitted from a sub-pixel R is incident on a linear polarizer 31a with a transmission axis of 0°, only the 0° linearly polarized component is transmitted. When 0° linearly polarized light is incident on a sub-pixel LC1 of the liquid crystal panel 29, its phase changes by λ / 4, and it can be emitted as, for example, left-circularly polarized light (L).

[0182] When unpolarized infrared light (emitted light IRe) emitted from a sub-pixel L is incident on a linear polarizer 31a with a transmission axis of 0°, only the 0° linearly polarized component is transmitted. When 0° linearly polarized light is incident on a sub-pixel LC2 of the liquid crystal panel 29, its phase changes by -λ / 4, and it can be emitted as right circularly polarized light (R), which has the opposite polarity to left circularly polarized light (L). In this way, by turning on either sub-pixel LC1 or sub-pixel LC2, the polarity of circularly polarized light can be made different for visible light and infrared light, similar to the case when different phase difference plates are used.

[0183] When the light emitted from pixel LC2 towards eye 40 is right-circularly polarized (R), the reflected light IRr reflected by eye 40 is incident on sub-pixel LC2 in a right-circularly polarized (R) state, so its phase changes by -λ / 4 and it is converted to 0° linearly polarized light. Therefore, it can pass through the linear polarizer 31a with a transmission axis of 0° and be incident on sub-pixel S.

[0184] Figure 21A shows a modified configuration of the setup shown in Figures 19A and 19B, in which a phase difference plate 33 is provided between the linear polarizer 31a and the liquid crystal panel 29. Since the linear polarizer 31a and the phase difference plate 33 act as circular polarizers, the light emitted from the phase difference plate 33 toward the eye 40 becomes circularly polarized. Figure 21A shows an example in which the visible light VL after passing through the liquid crystal panel 29 is left-circularly polarized (L), and the infrared light (emitted light IRe) is right-circularly polarized (R). Therefore, the changes in the optical path and polarization state beyond the half mirror 34 are the same as in Figure 10A.

[0185] Here, in the off state, the sub-pixels of pixel PIX_LC exhibit a phase modulation due to the orientation of liquid crystal molecules of λ / 2. In the on state, the phase modulation due to the orientation of liquid crystal molecules of the sub-pixels is 0. That is, the sub-pixel LC1 in the off state and the sub-pixel LC2 in the on state can be made to function similarly to a state where a phase difference plate capable of changing the phase by λ / 2 is provided and a state where a phase difference plate is not provided.

[0186] Figure 21B is a diagram of Figure 21A with the optical path LP3 added. The change in polarization state in the optical path LP3 until it passes through the half mirror 34 is the same as in Figure 13A. If the reflected light IRr specularly reflected by the eye 40 is 90° linearly polarized, the polarization state after passing through the half mirror 34 becomes right circularly polarized (R). Subsequently, after passing through LC2 with phase modulation 0, it is converted to right circularly polarized (R), and after passing through the phase difference plate 33 and the linear polarizer plate 31a, it is converted to 0° linearly polarized. Therefore, similar to Figure 13A, the reflected light IRr is incident on the sub-pixel S which functions as the sensor unit 23 in a state of 0° linear polarization.

[0187] In the configuration shown in Figures 21A and 21B, the configuration of the liquid crystal panel 29 and the method of generating circularly polarized light of different magnitudes using the liquid crystal panel 29 to create a phase difference will be explained with reference to Figures 22A and 22B.

[0188] Figures 22A and 22B show schematic cross-sectional views of the pixel PIX 4 and the liquid crystal panel 29. The pixel PIX 4 shows sub-pixel R, which is one of the sub-pixels that has the function of the display unit 21; sub-pixel L, which has the function of the light source unit 22; and sub-pixel S, which has the function of the sensor unit 23. The liquid crystal panel 29 shows, for example, sub-pixel LC1, which functions as a phase difference plate 32a; and sub-pixel LC2, which functions as a phase difference plate 32b. A linear polarizing plate 31a and a phase difference plate 33 are provided between the pixel PIX 4 (display panel 20) and the liquid crystal panel 29.

[0189] Figure 22A shows the off state, where no electric field is applied to either sub-pixel LC1 or sub-pixel LC2. In this state, both sub-pixel LC1 and sub-pixel LC2 behave the same way, so it is not possible to generate circularly polarized light of different polarities from the light emitted from pixel PIX4.

[0190] Figure 22B shows the sub-pixel LC1 in the off state and the sub-pixel LC2 in the on state with an electric field applied. Here, the phase modulation due to the orientation of liquid crystal molecules in the off state is assumed to be λ / 2, and the phase modulation due to the orientation of liquid crystal molecules in the on state is assumed to be 0. In other words, the sub-pixel LC1 in the off state and the sub-pixel LC2 in the on state can be made to function in the same way as phase difference plates 32a and 32b, whose slow axis is orthogonal to each other.

[0191] When unpolarized visible light VL emitted from a sub-pixel R is incident on a circular polarizer, specifically a linear polarizer 31a and a phase difference plate 33, it changes to, for example, right-circularly polarized light (R). When right-circularly polarized light (R) is incident on a sub-pixel LC1, its phase changes by λ / 2, allowing it to be inverted and emitted as left-circularly polarized light (L).

[0192] When unpolarized infrared light (emitted light IRe) emitted from sub-pixel L is incident on the linear polarizer 31a and phase difference plate 33, which are circular polarizers, it changes to, for example, right-circularly polarized light (R). The right-circularly polarized light (R) is incident on sub-pixel LC2, but since the phase change is 0, it can be emitted from sub-pixel LC2 in the state of right-circularly polarized light (R). Therefore, circularly polarized light of different polarities can be emitted from sub-pixel LC1 and sub-pixel LC2, respectively.

[0193] When the light emitted from pixel LC2 towards eye 40 is right-circularly polarized (R), the reflected light IRr reflected by eye 40 is incident on sub-pixel LC2 in a right-circularly polarized (R) state, so the phase change is 0 and it is emitted in a right-circularly polarized (R) state. The right-circularly polarized (R) light is converted to 0° linearly polarized light by the linear polarizer 31a and the phase difference plate 33, which are circular polarizers, and can be incident on sub-pixel S.

[0194] As described above, the liquid crystal panel 29 can be used with one of the sub-pixels LC1 and LC2 in the ON state and the other in the OFF state, but is not limited to this. Each sub-pixel can also be used in the ON state to enable desired phase modulation.

[0195] Furthermore, while the above example shows how to control the orientation of liquid crystal molecules by the presence or absence of an electric field applied to the liquid crystal element to determine the on and off states, this is not the only example. For instance, the orientation state of the liquid crystal molecules can be fixed with a resin or the like to create separate sub-pixels in the on and off states.

[0196] Figures 23A to 23C illustrate an example of fixing the orientation state of liquid crystal molecules. Figure 23A shows the initial state, where liquid crystal molecules are arranged in sub-pixels LC1 and LC2 such that the phase modulation of incident light is λ / 2, without applying an electric field to each sub-pixel. Here, a monomer is added along with the liquid crystal molecules between the pair of electrodes of the liquid crystal element. Alternatively, a liquid crystalline monomer can be used.

[0197] Figure 23B shows the sub-pixel LC1 in the off state (no electric field applied) and the sub-pixel LC2 in the on state (electric field applied). Here, with the electric field applied to sub-pixel LC2, the liquid crystal molecules are oriented such that, for example, the phase modulation becomes zero. By irradiating with ultraviolet (UV) light, heating, or both, while the liquid crystal molecules are in this desired orientation state, monomers can be polymerized to produce a polymer, thereby fixing the orientation state of the liquid crystal molecules.

[0198] Therefore, as shown in Figure 23C, since the orientation state of the liquid crystal molecules is fixed, even without applying an electric field, sub-pixel LC1 can impart a phase difference of λ / 2 to the incident light, and sub-pixel LC2 can impart a phase difference of 0.

[0199] Next, the acquisition of information about the eye 40 and its vicinity will be described. Figure 24A is a schematic diagram of a configuration in which light emitted from the light source unit 22 and reflected by the eye 40 is received by the sensor unit 23. The emitted light IRe from the light source unit 22, which travels toward the center of the eye 40, is reflected by the region 40R of the center of the eye 40 as viewed from the front, and the reflected light IRr that travels toward the sensor unit 23 is received by the sensor unit 23.

[0200] In this way, by obtaining information from region 40R, for example, when the eyeball is moved as shown in Figure 24B, the positions of the pupil 40a, iris 40b, and white of the eye 40c change, so dynamic information of the eye 40, such as gaze detection, can be accurately read from the reflected light information of region 40R. Note that the position and area of ​​the reflective surface can be changed according to the number of light-emitting elements to be emitted and the optical elements on the light-emitting elements.

[0201] Furthermore, as shown in Figure 24C, the movement of the eyelid 40d can also be read from multiple reflected light IRr, allowing for accurate acquisition of not only blink count information but also blink speed information.

[0202] Furthermore, in one aspect of the present invention, the number of light-emitting elements 22L in the light source unit 22 and the number of light-receiving elements 23S in the sensor unit 23 can each be multiple. Here, the specific operation when there are nine light-emitting elements 22L (light-emitting elements 22L1 to 22L9 from the upper eyelid side) and nine light-receiving elements 23S (light-receiving elements 23S1 to 23S9 from the upper eyelid side) will be explained using Figures 25A to 25C. Note that the number of light-emitting elements 22L and light-receiving elements 23S is not limited to these and can be set as appropriate depending on the purpose.

[0203] For example, by dividing each of the nine light-emitting elements 22L and nine light-receiving elements 23S into three sections, and driving the light-emitting elements 22L at different positions in a time-division system, and sequentially reading with the light-receiving elements 23S at different positions, dynamic information about the eye 40 and its vicinity can be accurately acquired. The number of light-receiving elements 23S driven at one time can be appropriately set according to the purpose, ranging from one to all of them.

[0204] The following describes the time-series operation of the time-division drive described above at times T1, T2, and T3.

[0205] First, at time T1, the three upper light-emitting elements 22L1 to 22L3 are lit, as shown in Figure 25A. At this time, the strong reflected light IRr reflected near the upper part of the eye 40, which is close to the light-emitting elements 22L1 to 22L3, mainly enters the three lower light-receiving elements 23S7 to 23S9, which are point-symmetrical with respect to the eye 40. Reflected light IRr also enters the light-receiving elements 23S1 to 23S6, but the amount of incident light decreases as the distance from the three lower light-receiving elements 23S1 to 23S3 increases. The size of the arrows schematically represents the amount of light.

[0206] Next, at time T2, as shown in Figure 25B, the three central light-emitting elements 22L4 to 22L6 are lit. At this time, the strong reflected light IRr reflected near the center of the eye 40, which is close to the light-emitting elements 22L4 to 22L6, mainly enters the three central light-receiving elements 23S4 to 23S6, which are point-symmetrical with respect to the eye 40. Reflected light IRr also enters the light-receiving elements 23S1 to 23S3 and 23S7 to 23S9, but the amount of reflected light decreases as the distance from the three central light-receiving elements 23S4 to 23S6 increases.

[0207] Next, at time T3, as shown in Figure 25C, the three lower light-emitting elements 22L7 to 22L9 are lit. At this time, the strong reflected light IRr reflected near the lower part of the eye 40, which is close to the light-emitting elements 22L7 to 22L9, mainly enters the three upper light-receiving elements 23S1 to 23S3, which are point-symmetrical with respect to the eye 40. Reflected light IRr also enters the light-receiving elements 23S4 to 23S9, but the amount of incident light decreases as the distance from the three upper light-receiving elements 23S1 to 23S3 increases.

[0208] In this way, by performing time-division driving, information from the upper, central, and lower parts of the eye 40 can be obtained in a time series, and the movement of the eye 40 can be accurately read. Furthermore, the movement of the eyelids and the speed of blinking can also be accurately read. In addition, by using artificial intelligence that has learned the relationship between the position and number of light-emitting elements, the intensity of light received by each of the multiple photodetectors, and the dynamic information of the eye 40 or its vicinity, the movement of the eye 40 and its vicinity can be inferred more accurately.

[0209] Next, the configuration of the light-emitting element used in the display unit 21, the light-emitting element used in the light source unit 22, and the photoelectric conversion element used as a light-receiving element in the sensor unit will be described.

[0210] 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.

[0211] Here, we describe an example in which the light-emitting element used in the light source unit 22, the photoelectric conversion element used in the sensor unit 23, and the light-emitting element used in the display unit 21 are manufactured using a common process, but the present invention is not limited to this. For example, only one of the light-emitting element used in the light source unit 22 and the photoelectric conversion element used in the sensor unit 23 may be manufactured using a process common to that used for the light-emitting element used in the display unit. Alternatively, the light-emitting element used in the light source unit 22 and the photoelectric conversion element used in the sensor unit 23 may each be manufactured using a different process than that used for the light-emitting element used in the display unit.

[0212] Figure 26A is a cross-sectional view of the top view of the display panel 20 shown in Figure 26C, along the line D1-D2, and corresponds to the cross-section of the light source unit 22 and a part (pixel) of the display unit 21. Figure 26B is a cross-sectional view of the top view of the display panel 20 shown in Figure 26C, along the line E1-E2, and corresponds to the cross-section of the sensor unit 23 and a part (pixel) of the display unit 21.

[0213] The display unit 21 has pixels, and each pixel has a plurality of sub-pixels with different emission colors. Each sub-pixel is provided with a light-emitting element. Here, we will describe a sub-pixel 105R that can emit red (R) light and corresponds to the aforementioned sub-pixel R, and a sub-pixel 105B that can emit blue (B) light and corresponds to the aforementioned sub-pixel B. Sub-pixel 105R has a light-emitting element 110R, and sub-pixel 105B has a light-emitting element 110B. The display unit 21 may also have a sub-pixel that emits green (G) light as an additional sub-pixel.

[0214] Furthermore, the light-emitting element of the light source unit 22 will be described as a light-emitting element 110IR capable of emitting infrared light. Furthermore, the photoelectric conversion element of the sensor unit 23 will be described as a photoelectric conversion element 110PD that converts infrared light into photoelectric energy.

[0215] The light-emitting element 110R, light-emitting element 110B, light-emitting element 110IR, and photoelectric conversion element 110PD are provided on a substrate 161. The substrate 161 is a support and also includes elements of circuits that drive each of the light-emitting elements 110R, 110B, 110IR, and photoelectric conversion element 110PD.

[0216] Preferably, the light-emitting elements 110R, 110B, and 110IR are OLEDs (Organic Light Emitting Diodes) or QLEDs (Quantum-dot Light Emitting Diodes). The light-emitting material of the EL element can be an organic compound or an inorganic compound (such as a quantum dot material).

[0217] The light-emitting element 110R has a pixel electrode 111R, an organic layer 112R, a common layer 114, and a common electrode 113. The light-emitting element 110B has a pixel electrode 111B, an organic layer 112B, a common layer 114, and a common electrode 113. The light-emitting element 110IR has a pixel electrode 111IR, an organic layer 112IR, a common layer 114, and a common electrode 113.

[0218] Although the light-emitting element 110IR is located outside the display unit 21, it includes components common to the pixels of the display unit 21, and is therefore treated here as an element equivalent to a pixel. The common layer 114 and common electrode 113 are provided in common to the light-emitting element 110R, the light-emitting element 110B, and the light-emitting element 110IR.

[0219] The organic layer 112R of the light-emitting element 110R contains a luminescent organic compound that emits at least red light. The organic layer 112B of the light-emitting element 110B contains a luminescent organic compound that emits at least blue light. The organic layer 112IR of the light-emitting element 110IR contains a luminescent organic compound that emits at least infrared light. The organic layers 112R, 112B, and 112IR can each also be called EL layers and each contains a layer (luminescent layer) that contains at least a luminescent substance.

[0220] In the following, when describing matters common to the light-emitting element 110R, light-emitting element 110B, and light-emitting element 110IR, they may be referred to simply as light-emitting element 110. Similarly, for components distinguished by letters, such as organic layer 112R, organic layer 112B, and organic layer 112IR, when describing matters common to them, the letters may be omitted and the corresponding symbols used.

[0221] The organic layer 112 and the common layer 114 can each independently have one or more of the following: an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. For example, the organic layer 112 may have a stacked structure of a hole injection layer, a hole transport layer, an emissive layer, and an electron transport layer from the pixel electrode 111 side, and the common layer 114 may have an electron injection layer.

[0222] Pixel electrodes 111R, 111B, and 111IR are provided for each light-emitting element. A common electrode 113 and a common layer 114 are provided as a continuous layer common to each light-emitting element. A conductive film that is transparent to visible light is used on either each pixel electrode or the common electrode 113, and a conductive film that is reflective is used on the other. By making each pixel electrode transparent and the common electrode 113 reflective, a bottom-emission type display device can be made. Conversely, by making each pixel electrode reflective and the common electrode 113 transparent, a top-emission type display device can be made. Furthermore, by making both each pixel electrode and the common electrode 113 transparent, a dual-emission type display device can be made.

[0223] A protective layer 121 is provided on the common electrode 113, covering the light-emitting elements 110R, 110B, and 110IR. The protective layer 121 has the function of preventing impurities such as water from diffusing to each light-emitting element from above.

[0224] It is preferable that the end of the pixel electrode 111 has a tapered shape. When the end of the pixel electrode 111 has a tapered shape, the organic layer 112 provided along the end of the pixel electrode 111 can also have a shape with an inclined portion. By making the end of the pixel electrode 111 tapered, the coverage of the organic layer 112 that is provided over the end of the pixel electrode 111 can be improved. Furthermore, by making the side surface of the pixel electrode 111 tapered, it becomes easier to remove foreign matter (for example, dust or particles) during the manufacturing process by washing or other processes, which is preferable.

[0225] In this specification, a tapered shape refers to a shape in which at least a portion of the side surface of the structure is inclined with respect to the substrate surface. For example, it is preferable to have a region in which the angle between the inclined side surface and the substrate surface (also called the taper angle) is less than 90°.

[0226] The organic layer 112 is processed into island-like layers using, for example, a resist mask formed by lithography. As a result, the organic layer 112 has a shape where the angle between the top surface and the side surface is close to 90 degrees at its edges. On the other hand, organic films formed using FMM (Fine Metal Mask) or the like tend to gradually become thinner towards the edges, and for example, the top surface is formed in a slope shape over a range of 1 μm to 10 μm, making it difficult to distinguish between the top surface and the side surface.

[0227] Between two adjacent light-emitting elements, there are insulating layers 124, 125, and 126.

[0228] Between two adjacent light-emitting elements, the sides of each organic layer 112 are positioned opposite each other with a resin layer 126 in between. The resin layer 126 is located between the two adjacent light-emitting elements and is provided to fill the ends of each organic layer 112 and the region between the two organic layers 112. The resin layer 126 has a smooth, convex upper surface shape, and a common layer 114 and a common electrode 113 are provided covering the upper surface of the resin layer 126.

[0229] The resin layer 126 functions as a planarizing film that fills the step between two adjacent light-emitting elements. By providing the resin layer 126, it is possible to prevent the common electrode 113 from being separated by the step at the edge of the organic layer 112 (also called step breakage), and to prevent the common electrode on the organic layer 112 from becoming insulated.

[0230] Furthermore, the resin layer 126 insulates the organic layers 112 of adjacent light-emitting elements 110 from each other. This reduces the leakage current through the organic layers 112 between adjacent light-emitting elements, thereby suppressing unwanted light emission due to crosstalk.

[0231] 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.

[0232] Furthermore, a photosensitive resin can be used as the resin layer 126. A photoresist may be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0233] The resin layer 126 may contain a material that absorbs visible light. For example, the resin layer 126 itself may be made of a material that absorbs visible light, or the resin layer 126 may contain a pigment that absorbs visible light. As the resin layer 126, for example, a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light, or a resin that contains carbon black as a pigment and functions as a black matrix can be used.

[0234] The resin layer 126 absorbs light emitted obliquely from the light-emitting element, thereby suppressing light leakage (stray light) from the light-emitting element to adjacent light-emitting elements via the resin layer 126. This improves the display quality of the display device. Furthermore, since the display quality can be improved without using a polarizing plate in the display device, the display device can be made lighter and thinner.

[0235] The insulating layer 125 is provided in contact with the side surface of the organic layer 112. The insulating layer 125 also covers the upper end of the organic layer 112. Furthermore, a portion of the insulating layer 125 is provided in contact with the upper surface of the substrate 161.

[0236] The insulating layer 125 is located between the resin layer 126 and the organic layer 112 and functions as a protective film to prevent the resin layer 126 from coming into contact with the organic layer 112. If the organic layer 112 and the resin layer 126 come into contact, the organic layer 112 may dissolve due to organic solvents used during the formation of the resin layer 126. Therefore, by providing the insulating layer 125 between the organic layer 112 and the resin layer 126, it is possible to protect the sides of the organic layer 112.

[0237] 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.

[0238] 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.

[0239] The insulating layer 125 can be formed using sputtering, CVD, PLD, ALD, or the like. It is preferable to form the insulating layer 125 using the ALD method, which provides good coverage.

[0240] Alternatively, a reflective film (for example, a metal film containing one or more selected from silver, palladium, copper, titanium, and aluminum) may be provided between the insulating layer 125 and the resin layer 126, and the light emitted from the light-emitting layer may be reflected by the reflective film. This can improve the light extraction efficiency.

[0241] 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 112 remains after etching the organic layer 112. 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.

[0242] In particular, metal oxide films such as aluminum oxide films and hafnium oxide films, or inorganic insulating films such as silicon nitride films and silicon oxide films, formed by the ALD method, have few pinholes and therefore offer excellent protection for the EL layer, making them suitable for use in insulating layers 125 and 124.

[0243] 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.

[0244] 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.

[0245] In the display unit 21, a plano-convex lens 102 (lenses 102R, 102B) is provided on the insulating layer 103 so as to overlap with the light-emitting element 110. An insulating layer 104 is also provided on the lens 102. The lens 102 is provided in pairs with the light-emitting element 110. In other words, one lens 102 is provided for each sub-pixel.

[0246] The lens 102 is positioned above the light-emitting element 110 (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 102 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. The lens 102 can be manufactured using the same material and process as the resin layer 126.

[0247] 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.

[0248] 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.

[0249] An optical element 26L, as shown in Figure 2C, is provided on the light-emitting element 110IR used as the light source unit 22. The optical element 26L can be formed using the same material as the resin layer 126, similar to the lens 102. Note that since reflow processes are not suitable for forming the optical element 26L (prism) shown in Figure 2C, it is preferable to form it using an imprint apparatus. Alternatively, a separately formed prism may be placed on the light-emitting element 110IR using a mounter apparatus or the like. Furthermore, a convex lens-shaped optical element 25L, as shown in Figure 2B, can also be provided on the light-emitting element 110IR.

[0250] Next, we will describe the photoelectric conversion element 110PD used as a light-receiving element. Note that we will omit the explanation of elements that are common with the light-emitting element 110, and elements that have common functions.

[0251] A pn-type or PIN-type photodiode can be used as the photoelectric conversion element 110PD. In the photoelectric conversion element 110PD, the amount of charge generated from the photoelectric conversion element 110PD is determined based on the amount of incident light.

[0252] The photoelectric conversion element 110PD can detect infrared light emitted by the light-emitting element 110IR. By using infrared light with low visual sensitivity, the impact on the visibility of the display unit 21 can be suppressed.

[0253] As the photoelectric conversion 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, they can be applied to various display devices.

[0254] 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 photoelectric conversion 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.

[0255] The photoelectric conversion element 110PD can detect light incident on it, generate an electric charge, and extract it as an electric current by driving it with a reverse bias applied between the pixel electrode and the common electrode. Although the photoelectric conversion element 110PD is located outside the display unit 21, it includes components common to the pixels of the display unit 21, and is therefore treated here as an element equivalent to a pixel.

[0256] The same manufacturing method as for the light-emitting element 110 can be applied to the photoelectric conversion element 110PD. The island-shaped active layer (also called the photoelectric conversion layer) of the photoelectric conversion 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 photoelectric conversion element 110PD can be improved.

[0257] The photoelectric conversion element 110PD has a pixel electrode 111PD, an organic layer 112PD, a common layer 114, and a common electrode 113.

[0258] The organic layer 112PD includes at least an active layer and preferably has multiple 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 photoelectric conversion element 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.

[0259] The organic layer 112PD is provided on the photoelectric conversion element 110PD but not on the light-emitting element 110. 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 110. 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 110.

[0260] Here, layers common to the photoelectric conversion element 110PD and the light-emitting element 110 may have different functions in the light-emitting element 110 and the photoelectric conversion element 110PD. In this specification, components may be referred to based on their function in the light-emitting element 110. For example, a hole injection layer functions as a hole injection layer in the light-emitting element 110 and as a hole transport layer in the photoelectric conversion element 110PD. Similarly, an electron injection layer functions as an electron injection layer in the light-emitting element 110 and as an electron transport layer in the photoelectric conversion element 110PD. Furthermore, layers common to the photoelectric conversion element 110PD and the light-emitting element 110 may have the same function in the light-emitting element 110 and the photoelectric conversion element 110PD. For example, a hole transport layer functions as a hole transport layer in both the light-emitting element 110 and the photoelectric conversion element 110PD, and an electron transport layer functions as an electron transport layer in both the light-emitting element 110 and the photoelectric conversion element 110PD.

[0261] Furthermore, the light-emitting element 110 is operated with a forward bias, while the photoelectric conversion element 110PD is operated with a reverse bias. Therefore, the light-emitting element 110 performs light emission with the potential magnitude of pixel electrode 111 > common electrode 113. The photoelectric conversion element 110PD performs light reception with the potential magnitude of common electrode 113 > pixel electrode 111PD.

[0262] An optical element 25S, for example, as shown in Figure 2B, is provided on the photoelectric conversion element 110PD used as a light-receiving element. The optical element 25S can be formed using the same material as the resin layer 126, similar to the lens 102. In Figure 26B, a convex lens is shown as an example of an optical element 28, but when using the prism-shaped optical element 26S shown in Figure 2C, it is preferable to form it using an imprint apparatus. Alternatively, a separately formed prism may be placed on the light-emitting element 110IR using a mounter apparatus or the like.

[0263] The insulating layer 104 provided on the lens 102, optical elements 26L and 25S is an adhesive layer provided between it and the substrate 163, and it is preferable to use an organic material. For example, an optical adhesive having a refractive index close to that of glass or film that can be used as the substrate 163 can be used.

[0264] The above describes examples of configurations for the light-emitting element used in the display unit, the light-emitting element used in the light source unit 22, and the light-receiving element and its vicinity used in the sensor unit 23.

[0265] Figure 27A is a block diagram illustrating a display panel according to one embodiment of the present invention. The display panel 20 has a pixel array 74 in the display section 21. It also has circuits 75 and 76 for driving the pixel array 74. The pixel array 74 has pixels 70 arranged in the column direction and row direction.

[0266] Furthermore, the display unit 21 has a light source unit 22 and a sensor unit 23 on its outside, and includes a circuit 72 for driving the light source unit 22 and a circuit 73 for driving the sensor unit 23.

[0267] Pixel 70 may have multiple sub-pixels 71. The sub-pixels 71 have the function of emitting light for display. By assigning colors such as R (red), G (green), and B (blue) to the light emitted by the sub-pixels 71, full-color display can be achieved.

[0268] The sub-pixel 71 has a light-emitting element that emits unpolarized visible light. The light source unit 22 also has a light-emitting element that emits infrared 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 EL elements include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence (TADF) materials, and inorganic compounds (such as quantum dot materials). LEDs such as microLEDs can also be used as the light-emitting element. The sensor unit 23 also has a photoelectric conversion element that can convert infrared light into photoelectric energy.

[0269] Circuits 75 and 76 are driver circuits for driving the sub-pixels 71. Circuit 75 can function as a source driver circuit, and circuit 76 can function as a gate driver circuit. Circuits 75 and 76 can be, for example, shift register circuits.

[0270] Circuit 72 is a driver circuit for driving the light source unit 22. Circuit 73 is a driver circuit for driving the sensor unit 23. Circuits 72 and 73 can also be shift register circuits, similar to circuits 75 and 76. However, if high-speed driving is not required, a power supply circuit for passive driving may be used.

[0271] Alternatively, the display panel 20 may be divided into multiple regions vertically and horizontally, and pixels may be driven in each of the divided regions.

[0272] For example, as shown in Figure 27B, circuits 75 and 76 can be separated and arranged below the pixel array 74. In this case, the display panel 20 can be made into a stacked structure of layers 77 and 78, with multiple circuits 75 and 76 each provided on layer 77, and the pixel array 74 placed on layer 78 so as to overlap them. Alternatively, circuit 72 can be placed below the light source unit 22, and circuit 73 can be placed below the sensor unit 23.

[0273] By dividing the circuits 75 and 76, the pixel array 74 can be driven in divided regions. For example, the pixel array 74 can be operated at partially different frame rates. The pixel array 74 can be displayed at partially different resolutions, and it can also be made compatible with foveal rendering.

[0274] Furthermore, by placing the driver circuit in the lower layer of the pixel array 74, the light source unit 22, and the sensor unit 23, the wiring length can be shortened and the wiring capacitance can be reduced. Therefore, a display device that can operate at high speed and with low power consumption can be made. In addition, the display panel 20 can have a narrow bezel.

[0275] Note that the arrangement and area of ​​circuits 72, 73, 75, and 76 shown in Figure 27B are examples and can be changed as appropriate. Also, parts of circuits 72, 73, 75, and 76 can be formed on the same layer as the pixel array 74. Furthermore, layers 77 may be provided with circuits such as memory circuits, arithmetic circuits, and communication circuits.

[0276] In this configuration, for example, layer 77 is provided on a single-crystal silicon substrate, circuits 75 and 76 are formed using transistors having silicon in the channel formation region (hereinafter referred to as Si transistors), and the pixel circuits of the pixel array 74 provided on layer 78 are formed using transistors having metal oxide in the channel formation region (hereinafter referred to as OS transistors). OS transistors can be formed using thin films and can be formed by stacking them on top of Si transistors.

[0277] As shown in Figure 27C, the configuration may also include a layer 79 between layer 77 and layer 78 on which an OS transistor is provided. The layer 79 can be provided with an OS transistor that forms part of the pixel circuit of the pixel array 74. Alternatively, it can be provided with an OS transistor that forms part of circuits 72, 73, 75, and 76. Alternatively, it can be provided with an OS transistor that forms part of circuits such as memory circuits, arithmetic circuits, and communication circuits that can be provided in layer 77.

[0278] Furthermore, the shape of the display panel 20 in a top view is not limited to a rectangle; it may also be circular, as shown in Figure 27D, or a polygon such as an octagon, as shown in Figure 27E.

[0279] Next, we will describe examples of circuits for driving light-emitting elements and circuits for driving light-receiving elements.

[0280] Figure 28A shows an example of the pixel circuit P1 of the sub-pixel 71. A similar circuit can also be used for the light source unit 22. The pixel circuit P1 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.

[0281] 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 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.

[0282] 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 P1. 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.

[0283] 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.

[0284] Figure 28B shows an example of a circuit P2 that drives the light-receiving element of the sensor unit 23. Circuit P2 includes a light-receiving element PD1, transistors M4, M5, M6, M7, and capacitor C2. Here, an example is shown in which a photodiode is used as the light-receiving element PD1.

[0285] 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.

[0286] 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.

[0287] Furthermore, as a variation of circuit P2, circuit P3 shown in Figure 28C can also be used. Circuit P3 differs from circuit P2 in that it has a transistor M13 and a capacitor C3. In Figure 28C, elements common to both circuit P2 and P3 are given the same reference numerals.

[0288] 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.

[0289] 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.

[0290] 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.

[0291] Circuit P3 has nodes FD1 and FD2, which can store 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.

[0292] 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.

[0293] 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.

[0294] In other words, by using circuit P3 as the light-receiving element of the sensor unit 23 in one aspect of the present invention, it is possible to read whether or not there is a change in the eye and its vicinity.

[0295] It is preferable to use OS transistors for the transistors M1 to M8 in the pixel circuits P1, P2, and P3. By using an oxide semiconductor with a large band gap for 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.

[0296] 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.

[0297] 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.

[0298] 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.

[0299] 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.

[0300] 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.

[0301] Therefore, it is preferable to use transistors made of oxide semiconductors, particularly for transistors M1, M4, M5, and M8, which have one or both of their sources or drains connected to capacitors C1, C2, or C3.

[0302] Furthermore, the manufacturing cost of other transistors can also be reduced by using transistors that utilize oxide semiconductors in a similar manner.

[0303] 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.

[0304] Furthermore, it is also possible to use transistors in which one or more of transistors M1 to M8 are made with oxide semiconductors, and the others are made with silicon.

[0305] Although Figures 28A to 28C illustrate an example using an n-channel transistor, a p-channel transistor can also be used.

[0306] Figure 29 shows an example of a goggle-type device having a display panel and optical equipment according to one embodiment of the present invention. Here, the combination of the display panel 20 and optical equipment 30 is shown as a display unit 60 with a dashed line.

[0307] The user can view the image displayed on the display panel 20 by bringing their eyes close to the optical device 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 optical device 30, they can experience a sense of immersion and presence.

[0308] As mentioned above, the optical device 30 converts the light emitted by the display unit into linearly polarized or circularly polarized light, 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 focal length of the optical device can be shortened. Such an optical system is called a reflective-refracting optical system. It is also sometimes called a pancake lens due to its thin shape.

[0309] The two sets of display units 60 are incorporated into the housing 61 such that the surface of the lens 68 is exposed on the inside. One display unit 60 is for the right eye and the other is for the left eye, and by displaying images corresponding to the parallax in each display unit 60, the user can perceive a sense of depth in the images.

[0310] Furthermore, the housing 61 or the holder 62 may be provided with input and output terminals. The input terminal can be connected to a cable that supplies video signals from a video output device, power for charging the battery, etc. The output terminal may function as an audio output terminal, for example, and earphones, headphones, etc. can be connected to it. However, if the system is configured to output audio data via wireless communication, or if audio is output from an external video output device, the audio output terminal does not need to be provided.

[0311] Furthermore, a wireless communication module and a storage module may be provided inside the housing 61 or the holder 62. The wireless communication module allows for wireless communication, enabling the download of content to be viewed and its storage in the storage module. This allows the user to view the downloaded content offline.

[0312] Furthermore, the light source unit 22 and sensor unit 23 of the display panel 20 can function as gaze detection sensors. The gaze detection sensors use the light emitted from the light source unit 22 to detect the position of the gaze by reading changes in reflected light due to the movement of the pupil, iris, and white of the eye. For example, changes in reflectivity caused by actions such as shifting the pupil to one side or up or down may be detected and assigned to the operation of electronic devices.

[0313] For example, operations such as power on, power off, sleep, volume adjustment, channel change, menu display, selection, confirmation, and back, as well as video playback, stop, pause, fast forward, and rewind, can be assigned to the eyelid opening and closing movements and eyeball movements described above. Furthermore, detected gaze information can also be used for foveal rendering.

[0314] Furthermore, the system may detect the user's fatigue level from dynamic changes in blinking and display an alert. Since blinking is strongly related to eye fatigue, the fatigue level can be estimated by detecting the number of blinks, intervals, and eyelid opening and closing speed within a unit of time.

[0315] If blinking behavior that suggests increasing fatigue is detected, the electronic device can take actions such as displaying a message or sound prompting a break, lowering the display brightness, or lowering the display color temperature to address the user's fatigue.

[0316] Furthermore, if a message or audio prompting a break is displayed, the user may feel uncomfortable if their work, entertainment, or immersion is interrupted against their will. Therefore, when prompting a break, it may be possible to activate devices that emit sound, vibration, or odor to guide the user to consciously want to take a break.

[0317] While the above example illustrates detecting fatigue through blinking, fatigue or illness may also be detected by obtaining other information. For example, by comparing the amount of reflected light on the surface of the eyeball with that of a normal eye, changes in the tear film can be detected to suppress dry eye or address dry eye symptoms. Additionally, the degree of eye opening (eyelid opening) can be detected by the amount of reflected light and compared with that of a normal eye to estimate the degree of fatigue.

[0318] Furthermore, conscious eyelid opening and closing can be used to perform input actions on electronic devices. For example, actions such as blinking with only one eye, blinking a predetermined number of times within a certain period of time, or closing the eyelids for a certain period of time can be assigned to operate electronic devices.

[0319] Figure 30A shows a block diagram of an example of a system for acquiring dynamic information from the eye 40 described above and reflecting it in the operation of an electronic device. The light source, display unit, and light receiving element are elements of the display panel 20 and can be provided, for example, in layer 78 shown in Figure 27B. The power supply circuit, drive circuit unit, amplification circuit, memory circuit, CPU (processing unit), and ADC (analog-to-digital converter) can be provided in layer 77 shown in Figure 27B.

[0320] An example of an operation that utilizes the dynamic information of the eye 40 is shown in the flowchart of Figure 30B. Here, we explain an example in which dynamic information of the eye 40 is acquired for a certain period of time, and when user fatigue is detected, actions to alleviate fatigue are fed back to the display device.

[0321] First, the measurement circuit is turned ON (S1) to start measuring dynamic information from the eye 40 (S2). Here, dynamic information can be, for example, information about the number of blinks or the blinking speed. The measurement circuit can be a light source, a power supply circuit, a photodetector, an amplification circuit, and an ADC, as shown in Figure 30A.

[0322] Measurement is performed continuously for a time set by the timer (S3) (for example, a few seconds to a few minutes), and the level of fatigue is determined (S4). The criteria for determining the level of fatigue can include, for example, the number of blinks within a certain period, or the time required for one blink.

[0323] If the system determines that the user is fatigued, the display device provides feedback (S5). The method of feedback is not limited to this; for example, it may include lowering the brightness of the display, lowering the color temperature of the display, or displaying a message prompting the user to take a break.

[0324] If it is determined that the user is not fatigued, the measurement circuit is turned OFF (S6), and after waiting for N seconds (S7), the system returns to S1. This operation is based on the fact that fatigue is cumulative and does not involve sudden changes, and also for power saving. Alternatively, if it is determined that the user is not fatigued, the system can return directly from S4 to S1.

[0325] This embodiment can be implemented in appropriate combination with other embodiments and examples described herein, at least in part.

[0326] (Embodiment 2) This embodiment describes an example of the configuration of a display panel that can be used as a display device according to one aspect of the present invention. In this embodiment, the light source and display unit shown in Figures 26A and 26C will be described using cross-sectional views, and a part of the configuration of the circuit that drives the light-emitting element will be mainly described. Here, an example is described in which a circuit for actively driving the light-emitting element of the light source is connected, but the light-emitting element may be passively driven.

[0327] [Display Panel 200A] The display panel 200A shown in Figure 31 has a substrate 301, light-emitting elements 110IR, 110R, a capacitor 240, and a transistor 310.

[0328] The transistor 310 is a transistor having a channel-forming region in the substrate 301. The substrate 301 can be a semiconductor substrate such as a single-crystal silicon substrate. The transistor 310 comprises a portion of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region of the substrate 301 doped with impurities and functions as either a source or a drain. The insulating layer 314 is provided covering the side surface of the conductive layer 311.

[0329] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0330] Furthermore, an insulating layer 261 is provided to cover the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0331] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located between them. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as the dielectric of the capacitor 240.

[0332] The conductive layer 241 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 the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided covering the conductive layer 241. The conductive layer 245 is provided in the region that overlaps with the conductive layer 241 via the insulating layer 243.

[0333] 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.

[0334] 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.

[0335] A light-emitting element 110IR and a light-emitting element 110R are provided on the insulating layer 255c. The configuration of the light-emitting element 110IR and the light-emitting element 110R can be found in Embodiment 1.

[0336] The display panel 200A has different light-emitting devices for each light-emitting color, resulting in minimal change in chromaticity between low-brightness and high-brightness illumination. Furthermore, because the organic layers 112IR and 112R are separated, crosstalk between adjacent sub-pixels can be suppressed even in high-resolution display panels. Therefore, a display panel that is both high-resolution and has high display quality can be realized.

[0337] An insulating layer 125 and a resin layer 126 are provided in the region between adjacent light-emitting elements.

[0338] The pixel electrodes 111IR and 111R of the light-emitting element are connected to either the source or drain of the transistor 310 by insulating layers 255a, 255b, 255c, and a plug 256 embedded in insulating layer 243, a conductive layer 241 embedded in insulating layer 254, and a plug 271 embedded in insulating layer 261. The height of the upper surface of insulating layer 255c and the height of the upper surface of plug 256 are equal or approximately equal. Various conductive materials can be used for the plugs.

[0339] Furthermore, a protective layer 121 is provided on the light-emitting elements 110IR and 110R. The substrate 163 is bonded to the protective layer 121 by an insulating layer 104 that functions as an adhesive layer.

[0340] There is no insulating layer covering the upper edge of the pixel electrode 111 between two adjacent pixel electrodes 111. Therefore, the spacing between adjacent light-emitting elements can be made extremely narrow. Consequently, a high-definition or high-resolution display panel can be made.

[0341] [Display Panel 200B] The display panel 200B shown in Figure 32 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.

[0342] 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.

[0343] 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.

[0344] 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.

[0345] 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.

[0346] 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.

[0347] 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).

[0348] [Display Panel 200C] The display panel 200C shown in Figure 33 has a configuration in which conductive layer 341 and conductive layer 342 are joined via bumps 347.

[0349] As shown in Figure 33, 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.

[0350] [Display Panel 200D] The display panel 200D shown in Figure 34 differs from the display panel 200A mainly in its transistor configuration.

[0351] Transistor 320 is an OS transistor in which a metal oxide (also called an oxide semiconductor) is applied to the semiconductor layer where the channel is formed.

[0352] 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.

[0353] 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.

[0354] 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.

[0355] 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.

[0356] 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.

[0357] 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.

[0358] 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.

[0359] 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.

[0360] 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.

[0361] 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.

[0362] 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.

[0363] 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.

[0364] 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.

[0365] 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.

[0366] 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.

[0367] As described above, by using OS transistors in the drive transistors included in the pixel circuit, it is possible to achieve "reduced power consumption," "increased luminescence brightness," "multi-gradation," and "suppression of variations in light-emitting devices."

[0368] [Display Panel 200E] The display panel 200E shown in Figure 35 has a configuration in which a transistor 310 with a channel formed on a substrate 301 and a transistor 320 containing a metal oxide in the semiconductor layer where the channel is formed are stacked.

[0369] An insulating layer 261 is provided covering the transistor 310, and a conductive layer 251 is provided on the insulating layer 261. An insulating layer 262 is provided covering the conductive layer 251, and a conductive layer 252 is provided on the insulating layer 262. The conductive layers 251 and 252 each function as wiring. An insulating layer 263 and an insulating layer 332 are provided covering the conductive layer 252, and a transistor 320 is provided on the insulating layer 332. An insulating layer 265 is provided covering the transistor 320, and a capacitor 240 is provided on the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0370] Transistor 320 can be used as a transistor constituting a pixel circuit. Transistor 310 can also be used as a transistor constituting a pixel circuit, or as a transistor constituting a drive circuit (gate line drive circuit, source line drive circuit) for driving the pixel circuit. Furthermore, transistors 310 and 320 can be used as transistors constituting various circuits such as arithmetic circuits or memory circuits.

[0371] This configuration allows for the formation of not only pixel circuits but also drive circuits directly beneath the light-emitting device, making it possible to miniaturize the display panel compared to cases where the drive circuits are located around the display area.

[0372] [Display Panel 200F] The display panel 200F shown in Figure 36 is a configuration in which the transistor 320 of the display panel 200E shown in Figure 35 is replaced with a transistor 320A (vertical transistor). This configuration of replacing transistor 320 with transistor 320A can also be applied to the display panel 200D shown in Figure 34.

[0373] Figure 37A shows a cross-sectional view of transistor 320A in the XZ plane. Figure 37B shows a cross-sectional view in the XY plane, including wiring 440.

[0374] The transistor 320A 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 320A. The wiring 440 has a region that functions as either the source electrode or the drain electrode of the transistor 320A.

[0375] 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.

[0376] 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.

[0377] 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.

[0378] As shown in Figure 37A, the oxide semiconductor 470 has a region 470i and regions 470na and 470nb that are provided so as to sandwich region 470i.

[0379] 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 transistor 320A. 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 transistor 320A. As shown in Figure 37B, 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 transistor 320A 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.

[0380] 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 320A. In other words, the channel formation region of transistor 320A 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 320A 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.

[0381] The channel length of transistor 320A is the distance between the source region and the drain region. In other words, the channel length of transistor 320A is determined by the thickness of the insulator 480 on the wiring 450. Figure 37A shows the channel length L of transistor 320A 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.

[0382] 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 thickness of the insulator 480. Therefore, the channel length of transistor 320A 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 transistor 320A.

[0383] 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 320A compared to a planar transistor where the channel formation region, source region, and drain region are provided separately on the XY plane. This allows for an increase in pixel density.

[0384] 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.

[0385] 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 37B. 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 320A is determined by the length of the outer circumference of the oxide semiconductor 470. That is, the channel width of the transistor 320A 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 37A and 37B show the maximum width D of the opening 490 with a double-headed arrow. Figure 37B shows the channel width W of the transistor 320A with a double-headed arrow. By increasing the maximum width D of the opening 490, the channel width per unit area can be increased, and the on-current can be increased.

[0386] 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".

[0387] Furthermore, in a memory device according to one aspect of the present invention, it is preferable that the channel length L of the transistor 320A is at least smaller than the channel width W of the transistor 320A. In one aspect of the present invention, the channel length L of the transistor 320A 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 320A. By adopting such a configuration, a transistor with good electrical characteristics and high reliability can be realized.

[0388] Further, by forming the opening 490 so as to be substantially circular in plan view, the oxide semiconductor 470, the insulator 430, and the conductor 420 are provided concentrically. As a result, the distance between the conductor 420 and the oxide semiconductor 470 becomes substantially uniform, so that a gate electric field can be applied to the oxide semiconductor 470 substantially uniformly.

[0389] In the channel formation region of a transistor using an oxide semiconductor for the semiconductor layer, it is preferable that the oxygen deficiency is less or the impurity concentration such as hydrogen, nitrogen, and metal elements is lower than that in the source region and the drain region. For example, the concentration of aluminum in the channel formation region of the oxide semiconductor is preferably 1×10 ２２ atoms / cm ３ or less, more preferably 1×10 ２１ atoms / cm ３ or less, still more preferably 1×10 ２０ atoms / cm ３ or less, still more preferably 5×10 １９ atoms / cm ３ or less, still more preferably 1×10 １９ atoms / cm ３ or less, still more preferably 5×10 １８ atoms / cm ３ or less, still more preferably 1×10 １８ atoms / cm ３ or less is even more preferable.

[0390] Further, since hydrogen near the oxygen deficiency may form a defect in which hydrogen enters the oxygen deficiency (hereinafter sometimes referred to as V Ｏ H) and generate electrons serving as carriers, it is preferable that V Ｏ ) H is also reduced in the channel formation region. Thus, the channel formation region of the transistor is a high-resistance region with a low carrier concentration. Therefore, it can be said that the channel formation region of the transistor is of i-type (intrinsic) or substantially i-type.

[0391] Further, in the source region and the drain region of a transistor using an oxide semiconductor for the semiconductor layer, the oxygen deficiency is larger and V ＯThis region has a high concentration of hydrogen (H), or high concentrations of impurities such as hydrogen, nitrogen, and metallic elements, resulting in increased carrier concentration and low resistance. In other words, the source and drain regions of a transistor are n-type regions with higher carrier concentration and lower resistance compared to the channel formation region.

[0392] In Figure 37A 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.

[0393] This embodiment can be implemented in appropriate combination with other embodiments and examples described herein, at least in part.

[0394] (Embodiment 3) This embodiment describes an indium oxide film that can be used in the semiconductor layer of a transistor in a display panel according to one aspect of the present invention.

[0395] 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.

[0396] 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.

[0397] This paper describes the carrier concentration dependence of the hole mobility of indium oxide, silicon, and IGZO.

[0398] 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.

[0399] 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).

[0400] 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.

[0401] 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.

[0402] 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.

[0403] 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.

[0404] 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.

[0405] 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.

[0406] 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.

[0407] 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.

[0408] 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.

[0409] 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.

[0410] 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.

[0411] 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.

[0412] 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.

[0413] 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.

[0414] 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.

[0415] 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) is less than or equal to 1aA (1 × 10) under room temperature (25°C) conditions. −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.

[0416] 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.

[0417] As one method for evaluating the degree of lattice mismatch, there is a method that uses the value of lattice mismatch shown below. The lattice mismatch Δa [%] of the crystal of the formed film (here, an indium oxide film) with respect to the crystal of the seed layer is Δa = ((L １ − L ２ ) / L ２ ) × 100. Here, L １ is the length of the unit lattice vector or lattice constant of the crystal of the formed film, and L ２ is the length of the unit lattice vector or lattice constant of the crystal of the seed layer.

[0418] The lattice mismatch Δa between the seed layer and the indium oxide film is preferably smaller in absolute value, and most preferably 0. 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.

[0419] Here, the crystal of indium oxide has a cubic crystal structure (bixbyite type). For example, the crystal of yttria-stabilized zirconia (YSZ) can have a cubic crystal structure (fluorite type). The lattice mismatch of the crystal of indium oxide with respect to the crystal of cubic crystal structure YSZ is within the range of −2% or more and 2% or less, and a single crystal film of indium oxide can be epitaxially grown on the YSZ substrate.

[0420] Note that the crystal structure of the seed layer and the crystal structure of the indium oxide film may not have the same crystal system or crystal orientation. For example, a film having a crystal of hexagonal crystal structure or trigonal crystal structure can also be used under an indium oxide film having a crystal of 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 lower surface of the indium oxide film to

[111] , the requirements related to the crystal orientation necessary for epitaxial growth can be satisfied. As crystals of hexagonal crystal system or trigonal crystal system, for example, there are wurtzite type structure, YbFe ２ O ４ type structure, Yb ２ Fe ３ O ７ ​２ O ４ Type structure or Yb ２ Fe ３ O ７ An example of a crystal having a type structure is IGZO.

[0421] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0422] 20: Display panel, 20g: Substrate, 21: Display unit, 21a: Area, 21b: Area, 21c: Area, 22: Light source unit, 22L: Light-emitting element, 23: Sensor unit, 23S: Light-receiving element, 25: Optical element, 25L: Optical element, 25S: Optical element, 26L: Optical element, 26S: Optical element, 27: Layer, 28: Optical element, 29: Liquid crystal panel, 30: Optical equipment, 31: Linear polarizer, 31a: Linear polarizer, 31b: Linear polarizer, 32: Phase difference plate, 32a: Phase difference plate, 32b: Phase difference plate, 33: Phase difference plate, 34: Half mirror, 35: Phase difference plate, 36: Reflective polarizer, 40: Eye, 40 a: Pupil, 40b: Iris, 40c: White of the eye, 40d: Eyelid, 40R: Region, 51: Lens, 52: Support, 53: Support, 54: Support, 55: Support, 57: Optical axis, 60: Display unit, 61: Housing, 62: Holder, 68: Lens, 70: Pixel, 71: Sub-pixel, 72: Circuit, 73: Circuit, 74: Pixel array, 75: Circuit, 76: Circuit, 77: Layer, 78: Layer, 79: Layer, 102: Lens, 102B: Lens, 102R: Lens, 103: Insulating layer, 104: Insulating layer, 105B: Sub-pixel, 105R: Sub-pixel, 110: Light-emitting element, 110B: Light-emitting element, 110 IR: Light-emitting element, 110PD: Photoelectric conversion element, 110R: Light-emitting element, 111: Pixel electrode, 111B: Pixel electrode, 111IR: Pixel electrode, 111PD: Pixel electrode, 111R: Pixel electrode, 112: Organic layer, 112B: Organic layer, 112IR: 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, 161: Substrate, 163: Substrate, 200A: Display panel, 200B: Display panel, 200C: Display panel, 200D: Display panel, 200E: Display panel, 20 0F: Display panel, 240: Capacitance, 241: Conductive layer, 243: Insulating layer, 245: Conductive layer, 251: Conductive layer, 252: Conductive layer, 254: Insulating layer, 255a: Insulating layer, 255b: Insulating layer, 255c: Insulating layer, 256: Plug, 261: Insulating layer, 262: Insulating layer, 263: Insulating layer, 264: Insulating layer, 265: Insulating layer, 271: Plug, 274: Plug, 274a: Conductive layer, 274b: Conductive layer, 301: Substrate, 301A: Substrate, 301B: Substrate, 310: Transistor, 310A: Transistor, 310B: Transistor, 311: Conductive layer, 312: Low resistance region313: insulating layer, 314: insulating layer, 315: element isolation layer, 320: transistor, 320A: transistor, 321: semiconductor layer, 323: insulating layer, 324: conductive layer, 325: conductive layer, 326: insulating layer, 327: conductive layer, 328: insulating layer, 329: insulating layer, 331: substrate, 332: insulating layer, 335: insulating layer, 336: insulating layer, 341: conductive layer, 342: conductive layer, 343: plug, 344: insulating layer, 345: insulating layer, 346: insulating layer, 347: bump, 348: adhesive layer, 420: conductor, 430: insulator, 440: wiring, 450: wiring, 470: oxide semiconductor, 470i: region, 470na: region, 470nb: region, 480: insulator, 490: opening,

Claims

An electronic device worn in front of the eye, It has a display panel and a reflective / refracting optical system, The reflective / refracting optical system is positioned between the display panel and the eye. The aforementioned display panel has a display unit, a light source unit, and a sensor unit. The aforementioned reflective-refracting optical system comprises a half-mirror and a reflective polarizer. An electronic device having: a first optical path through which visible light emitted from the display unit reaches the eye through reflection and transmission by the reflective polarizing plate and the half mirror; a second optical path through which infrared light emitted from the light source unit reaches the eye through transmission by the half mirror and the reflective polarizing plate; and a third optical path through which the infrared light reflected by the eye enters the sensor unit through transmission by the reflective polarizing plate and the half mirror. 　 In claim 1, The display panel has the display unit, the light source unit, and the sensor unit on the same plane. The display unit is an electronic device located between the light source unit and the sensor unit. 　 In claim 1, The aforementioned reflective / refracting optical system is On the first optical path, from the display panel side, there are, in order: a linear polarizer, a first phase difference plate, the half mirror, a second phase difference plate, and the reflective polarizer. On the second optical path, the linear polarizer, the third phase difference plate, the half mirror, the second phase difference plate, and the reflective polarizer are arranged in order from the display panel side. An electronic device in which the phase-lagging axes of the first phase difference plate and the third phase difference plate are perpendicular to each other. 　 In claim 3, The aforementioned reflective / refracting optical system is An electronic device having elements in common with those in the second optical path on the third optical path. 　 In claim 3, The aforementioned reflective / refracting optical system is An electronic device having, in order from the display panel side, the half mirror, the second phase difference plate, and the reflective polarizing plate on the third optical path. 　 In claim 1, The aforementioned reflective / refracting optical system is The first optical path includes, in order from the display panel side, a first linear polarizer, a first phase difference plate, the half mirror, a second phase difference plate, and the reflective polarizer. The second optical path includes, in order from the display panel side, a second linear polarizer, a first phase difference plate, a half mirror, a second phase difference plate, and a reflective polarizer. An electronic device in which the transmission axes of the first linear polarizer and the second linear polarizer are perpendicular to each other. 　 In claim 6, The aforementioned reflective / refracting optical system is An electronic device having elements in common with those in the second optical path on the third optical path. 　 In claim 6, The aforementioned reflective / refracting optical system is An electronic device having, in order from the display panel side, the half mirror, the second phase difference plate, and the reflective polarizing plate on the third optical path. 　 In claim 1, The light source unit is an electronic device having a plurality of light-emitting elements. 　 In claim 1, The sensor unit is an electronic device having a plurality of light-receiving elements. 　 In claim 1, The light-emitting element of the display unit, the light-emitting element of the light source unit, and the light-receiving element of the sensor unit are each connected to a transistor, and the transistor is an electronic device having a metal oxide in its channel-forming region. 　 In claim 11, The aforementioned metal oxide is indium oxide in an electronic device. 　 An electronic device worn in front of the eye, It has a display panel and a reflective / refracting optical system, The reflective / refracting optical system is positioned between the display panel and the eye. The display panel has a first pixel having a first sub-pixel having a light-emitting element that emits visible light, a second sub-pixel having a light-emitting element that emits infrared light, and a third sub-pixel having a light-receiving element. The aforementioned reflective-refracting optical system comprises a half-mirror and a reflective polarizer. An electronic device having a first optical path through which visible light reaches the eye by reflection and transmission through the reflective polarizer and the half mirror; a second optical path through which infrared light reaches the eye by transmission through the half mirror and the reflective polarizer; and a third optical path through which the infrared light reflected by the eye is incident on the third sub-pixel by transmission through the reflective polarizer and the half mirror. 　 In claim 13, The aforementioned reflective / refracting optical system is An electronic device having, in order from the display panel side, a linear polarizing plate, a liquid crystal panel, the half mirror, a phase difference plate, and the reflective polarizing plate on the first optical path, the second optical path, and the third optical path. 　 In claim 14, The liquid crystal panel has a second pixel, The second pixel has a fourth subpixel having an area that overlaps with the first subpixel, and a fifth subpixel having an area that overlaps with the second subpixel and the third subpixel, respectively. An electronic device having the function of causing the optical modulation of the liquid crystal elements of the fourth sub-pixel and the fifth sub-pixel to be different. 　 In claim 13, The light-emitting element of the first sub-pixel, the light-emitting element of the second sub-pixel, and the light-receiving element of the third sub-pixel are each connected to a transistor, and the transistor is an electronic device having a metal oxide in its channel-forming region. 　 In claim 16, The aforementioned metal oxide is indium oxide in an electronic device. 　 An electronic device according to any one of claims 1 to 17, wherein the electronic device has a function of operating the electronic device by detecting the movement of the eyes.

Images