Optical device and electronic device

Abstract

Provided is an optical device that is compact, lightweight, and achieves high light use efficiency. This optical device has: a catadioptric system that achieves high light use efficiency and causes image formation positions on two optical paths to coincide with each other; and a singlet lens that has the function of optical correction or the like and is between a non-polarized light source and the catadioptric system. A resin lens is disposed in an optical path using non-polarized light, and a glass lens that does not substantially generate birefringence is disposed in an optical path using polarized light. Thus, the partial unpolarization of polarized light can be prevented, and an optical device that is lightweight and achieves high light use efficiency with little stray light can be provided.

Description

Optical and Electronic Equipment

[0001] One aspect of the present invention relates to an optical instrument.

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

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

[0004] Goggle-type devices and eyeglass-type devices have been developed as electronic devices for XR (a collective term for virtual reality (VR), augmented reality (AR), mixed reality (MR), etc.).

[0005] XR equipment such as goggle-type devices is desirably small and thin to improve portability and wearability. Therefore, such electronic devices use thin catadioptric systems designed to have a short focal length. For example, Patent Literature 1 discloses a catadioptric system that reduces losses in transmission and reflection of polarized light and improves light utilization efficiency.

[0006] WO2023 / 126740

[0007] Generally, the catadioptric systems used in XR devices utilize selective reflection of polarized light, resulting in insufficient light utilization efficiency. For this reason, XR devices require the use of display devices with increased brightness. Increasing the brightness of display devices increases power consumption and reduces the reliability of the display devices. Therefore, optical devices with high light utilization efficiency are desired.

[0008] Furthermore, the goggle-type device is a device worn on the body, and is preferably small and lightweight to reduce the burden on the body.

[0009] Therefore, an object of one embodiment of the present invention is to provide an optical device with high light utilization efficiency. Another object is to provide an optical device with little stray light. Another object is to provide a small and lightweight optical device. Another object is to provide a small electronic device including the optical device. Another object is to provide an electronic device with low power consumption. Another object is to provide a novel electronic device.

[0010] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these will become clear from the description of the specification, drawings, claims, etc., and it is possible to extract other problems from the description of the specification, drawings, claims, etc.

[0011] One aspect of the present invention relates to an optical device that is small, lightweight, and has high light utilization efficiency.

[0012] One aspect of the present invention is an optical device applicable to an electronic device that uses a non-polarized light source, the optical device having a first lens and a catadioptric system, the first lens being provided between the non-polarized light source and the catadioptric system, the first lens being an aspherical singlet lens, the catadioptric system having a second lens, a third lens, and a unit having a half mirror between the first support and the second support, the unit being provided between the second lens and the third lens, the first lens being made of resin, and the first support, the second support, the second lens, and the third lens being made of glass.

[0013] It is preferable that the first lens has a region that acts as a convex lens and a region that acts as a concave lens, and that the shapes of the front and back surfaces are asymmetrical.

[0014] The catadioptric system has a plurality of optical elements arranged in plane symmetry with respect to the half mirror, and it is preferable that a pair of plane symmetric optical elements have the same optical characteristics.

[0015] It is preferable that the catadioptric optical system has a first reflective polarizer, a second reflective polarizer, a first retardation plate, and a second retardation plate, and that the second lens and the first retardation plate are provided between the first reflective polarizer and the first support, and the third lens and the second retardation plate are provided between the second reflective polarizer and the second support.

[0016] The catadioptric optical system is preferably arranged in the following order: a first reflective polarizer, a second lens, a first retardation plate, a first support, a half mirror, a second support, a second retardation plate, a third lens, and a second reflective polarizer.

[0017] The first support and the second support may be flat, and the first convex lens and the second convex lens may each be a spherical lens or an aspherical lens.

[0018] Another embodiment of the present invention is an electronic device including an organic electroluminescence (EL) panel having a microlens provided on an organic EL element as the non-polarized light source.

[0019] According to one embodiment of the present invention, an optical device with high light utilization efficiency can be provided. Alternatively, an optical device with little stray light can be provided. Alternatively, a small and lightweight optical device can be provided. Alternatively, a small electronic device including the optical device can be provided. Alternatively, an electronic device with low power consumption can be provided. Alternatively, a novel electronic device can be provided.

[0020] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims.

[0021] FIG. 1 is a diagram illustrating an electronic device. FIGS. 2A to 2H are diagrams illustrating lenses. FIG. 3 is a diagram illustrating an optical device. FIG. 4 is a diagram illustrating light utilization efficiency in an optical device. FIG. 5 is a diagram illustrating a reflecting surface and an imaging position of an optical device. FIGS. 6A and 6B are diagrams illustrating an optical device. FIGS. 7A and 7B are diagrams illustrating an optical path. FIGS. 8A and 8B are diagrams illustrating an optical device. FIGS. 9A to 9E are diagrams illustrating a display panel. FIGS. 10A and 10B are diagrams illustrating an eyeglass-type device. FIGS. 11A to 11C are diagrams illustrating an example configuration of a display panel. FIGS. 12A to 12C are diagrams illustrating an example configuration of a display panel. FIGS. 13A to 13F are diagrams illustrating an example configuration of a pixel. FIGS. 14A and 14B are diagrams illustrating an example configuration of a display panel. FIG. 15 is a diagram illustrating an example configuration of a display panel. FIG. 16 is a diagram illustrating an example configuration of a display panel. FIG. 17 is a diagram illustrating an example configuration of a display panel. Fig. 18 is a diagram illustrating an example of the configuration of a display panel. Fig. 19 is a diagram illustrating an example of the configuration of a display panel. Fig. 20 is a diagram illustrating an example of the configuration of a display panel. Figs. 21A and 21B are diagrams illustrating transistors.

[0022] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and those skilled in the art will readily understand that various modifications in form and detail may be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below. In the configuration of the invention described below, the same parts or parts having similar functions will be designated by the same reference numerals in different drawings, and repeated description thereof may be omitted. Hatching of the same elements constituting the drawings may be omitted or changed as appropriate in different drawings.

[0023] Furthermore, even if a circuit diagram shows a single element, that element may be configured as multiple elements as long as there is no functional problem. For example, multiple transistors operating as switches may be connected in series or parallel. Also, a capacitor may be divided and placed in multiple locations.

[0024] Furthermore, one conductor may have multiple functions, such as wiring, electrode, and terminal, and in this specification, multiple names may be used for the same element. Also, even when elements are shown as being directly connected to each other on a circuit diagram, in reality, the elements may be connected via one or more conductors, and in this specification, such a configuration is also included in the category of direct connection.

[0025] Embodiment 1 In this embodiment, an optical device and an electronic device according to one embodiment of the present invention will be described.

[0026] One embodiment of the present invention is an optical device that can be used in electronic devices such as goggle-type devices or eyeglass-type devices. The optical device includes a singlet lens and a catadioptric system, and the singlet lens is provided between a light source and the catadioptric system. The singlet lens has one or both of an optical correction function and a magnification enhancement function.

[0027] Here, a catadioptric system is an optical device that combines an element that acts as a lens and an element that acts as a mirror. The catadioptric system used in one embodiment of the present invention has two optical paths, and by symmetrically arranging the components, it is possible to align the image positions of the two optical paths. In other words, it is an optical system with high light utilization efficiency.

[0028] It is preferable that the components of a goggle-type device and the like are lightweight, and that the lenses are made of resin. However, when resin lenses are used in a catadioptric optical system that uses polarized light, stray light that deviates from the normal optical path is easily generated due to the effect of birefringence.

[0029] Therefore, in one aspect of the present invention, a glass lens that does not substantially cause birefringence is used in the catadioptric system. Meanwhile, a resin lens is used as a singlet lens provided between the light source and the catadioptric system. Furthermore, a non-polarized light source such as an organic EL panel or an LED (Light Emitting Diode) panel is used as the light source. By using a non-polarized light source, the influence of birefringence due to the resin singlet lens can be eliminated.

[0030] With this configuration, it is possible to provide an optical device that is highly efficient in using light, lightweight, and produces little stray light, as well as electronic equipment that includes the optical device.

[0031] The optical device according to one embodiment of the present invention has a configuration in which multiple elements (optical components) are combined. The configuration housed in a housing is also simply called a lens. Furthermore, due to its thin shape, the catadioptric system or the entire optical device is sometimes called a pancake lens.

[0032] FIG. 1 is a perspective view illustrating an electronic device of one embodiment of the present invention, showing a display panel and an optical device included in the electronic device. The display panel 20 is disposed so that the display unit 21 intersects perpendicularly with the optical axis 46 of the optical device 30. Note that in this specification, "perpendicular" refers to a state in which two lines form an angle of 85° or more and 95° or less. Here, one of the two lines refers to the optical axis 46 of the optical device 30, and the other refers to a line parallel to the display unit (display surface). Note that the shapes of the elements shown in FIG. 1 are merely examples.

[0033] The user can view the image displayed on the display panel 20 by bringing the eye 10 close to the optical device 30. The user can view the image with the viewing angle widened by the optical device 30, which gives the user a sense of immersion and realism.

[0034] The optical device 30 has a lens 54 and a catadioptric system 40, and the optical axes of the two are aligned to form an optical axis 46.

[0035] The catadioptric optical system 40 has a configuration in which a reflective polarizer 62, a lens 32, a retardation plate 63, a half mirror 31, a retardation plate 33, a lens 35, and a reflective polarizer 34 are arranged in this order. Note that a combination of a polarizer and a retardation plate (the reflective polarizer 62 and the retardation plate 63, or the retardation plate 33 and the reflective polarizer 34) is also called a circular polarizer that converts unpolarized light into circularly polarized light.

[0036] 1 illustrates an example in which the catadioptric system 40 includes the lens 32 and the lens 35, but the present invention is not limited to this. Other lenses may be provided. Furthermore, the order of some of the above-described elements may be reversed.

[0037] 1 shows an example in which all elements constituting the catadioptric optical system 40 are arranged close to each other, but this is not limiting, and the elements constituting the catadioptric optical system 40 may be divided into several units, and each unit may be arranged separately. In such a case, a support may be provided for each unit. Furthermore, a lens may be used as the support.

[0038] To arrange the adjacent elements in close proximity to each other, it is preferable to bond the elements together using an optical adhesive that has high transmittance for the wavelength of light to be used (for example, in the wavelength range of visible light or the wavelength range from blue light to red light) and that does not absorb or birefringence for specific polarized light. Alternatively, instead of bonding, one element may be formed in contact with the other element using a method such as coating or film formation. Alternatively, one element and the other element may be arranged in contact with each other without providing an adhesive or the like between them. Alternatively, a gap may be provided between the two.

[0039] Furthermore, an anti-reflection layer may be provided on the surface of a light-transmitting element that has an interface with air. Preventing unnecessary reflection on the surface of the element (the interface between air and the element) can improve light utilization efficiency and suppress the generation of stray light. Note that an anti-reflection layer is not required for half mirrors and reflective polarizers, which also have a reflective function.

[0040] The antireflection layer can be a film-type antireflection coating or a dielectric multilayer coating. For example, it is preferable to provide a dielectric multilayer coating on a curved surface such as the surface of a lens, where it is difficult to attach a film. Furthermore, for elements with flat surfaces, either a film-type antireflection coating or a dielectric multilayer coating may be provided. However, if the element on which the antireflection layer is formed is a resin film, the element may be thermally damaged during the process of forming the dielectric multilayer coating. In such cases, it is preferable to provide a film-type antireflection coating on the element via an adhesive.

[0041] Film-type antireflection coatings include a type that cancels out reflected light by interference, and a moth-eye type that continuously changes the refractive index by fine protrusions formed on the surface. In either type, it is preferable to use a film that is not produced by a stretching method as the base film. Films produced by a stretching method may have optical anisotropy, which may change the polarization state. In terms of small angle dependence and wavelength dependence, it is preferable to use a moth-eye type.

[0042] The lens 54 has an optical correction function, a function of increasing magnification, etc. The lens 54 may also be called a correction lens, an auxiliary lens, etc. depending on its function.

[0043] 2A is a diagram illustrating an example of a cross section including the optical axis of the lens 54. The lens 54 has regions A1 and A2 that function as convex lenses and regions B1 and B2 that function as part of a concave lens. While FIG. 2A shows an example in which regions A1 and B1 are provided on the light incident side (front side) of the lens 54 and regions A2 and B2 are provided on the light exit side (rear side), the front and back sides may be reversed. Furthermore, in FIGS. 2C to 2H described below, the front and back sides do not matter with respect to the incident light.

[0044] The lens 54 is preferably an aspherical singlet lens rather than a combination of multiple lenses. The effect of the lens 54 can also be achieved by combining multiple lenses, such as a convex lens 56 and a concave lens 57, as shown in FIG. 2B. However, using an aspherical singlet lens for the lens 54 can reduce the weight and the overall length of the optical device 30.

[0045] 2B, multiple interfaces with different refractive indices are generated in the optical path passing through the lenses, resulting in increased loss due to reflection. Therefore, it is preferable that lens 54 be a singlet lens in order to suppress loss of light intensity.

[0046] 2B shows two lenses as an example, three or more lenses may be required to achieve the desired effect. In other words, by using an aspherical lens as lens 54, the effect achieved by combining multiple lenses can be achieved with a single lens.

[0047] FIG. 2A shows an example in which the surface shape differs between the light entrance side and the light exit side. This shape allows for different diffusion and focusing effects in the central and peripheral areas, making it possible to correct fine aberrations. Furthermore, by independently adjusting the curvature of the front surface and the back surface, for example, by providing the opposite surface with a curvature greater than that of the diffusion section, it becomes possible to achieve a focusing effect overall. In other words, the configuration shown in FIG. 2A allows for correction by the area functioning as a concave lens, while still functioning as a convex lens for magnification overall.

[0048] The effects required of the lens 54 are diverse and vary depending on the configuration of the catadioptric system to be combined. Therefore, as shown in FIG. 2C, the lens may have the same shape on the light incident side and the light exit side. Alternatively, as shown in FIG. 2D, one of the light transmitting surfaces may be flat. Alternatively, as shown in FIG. 2E, one of the light transmitting surfaces may have only a region B2 functioning as a concave lens. Alternatively, as shown in FIG. 2F, one of the light transmitting surfaces may have only a region A2 functioning as a convex lens. Alternatively, as shown in FIG. 2G, the lens 54 may be a convex lens. Alternatively, as shown in FIG. 2H, the lens 54 may be a concave lens.

[0049] The shape of the lens 54 may be determined depending on the desired effect, and a spherical lens may be used. Also, depending on the effect that takes priority, the lens 54 may be configured by combining a plurality of lenses.

[0050] The areas A1 and A2 functioning as convex lenses have the effect of suppressing the divergence of light emitted from the light source and directing the light in the direction of the catadioptric optical system 40. They can also have the function of magnifying the image on the display unit 21.

[0051] Areas B1 and B2, which function as concave lenses, have the function of suppressing field curvature. Field curvature is a phenomenon in which the focal plane shifts between the center and periphery of an image, i.e., the image plane is not flat. An index of field curvature is the Petzval sum, which is calculated from the refractive indexes and focal lengths of two or more lenses. When the Petzval sum is 0, the image plane becomes flat, which is a desirable characteristic for the lens as a whole. To achieve this, the refractive index or focal length needs to be negative, but since the refractive index cannot be negative, it is preferable to combine concave lenses with negative focal lengths.

[0052] Furthermore, since the refractive index of lens materials generally varies depending on the wavelength, the focal position of the lens varies depending on the wavelength. In other words, chromatic aberration occurs. In order to reduce chromatic aberration, it is effective to combine a convex lens and a concave lens to reduce the difference in focal position depending on the wavelength. In other words, lens 54 can also have the function of reducing chromatic aberration.

[0053] Furthermore, since it is desirable for a goggle-type device to be lightweight, it is preferable that the materials of the components have a low specific gravity. Therefore, from the viewpoint of weight, it is desirable that all the lenses used in the optical device 30 be made of resin.

[0054] However, resins have the property of being prone to birefringence. In materials with birefringence, the refractive index differs depending on the vibration direction of polarized light, so the transmission speed differs for each polarized component. Therefore, after passing through the material, a phase difference occurs between the polarized components, causing a change in the polarization state.

[0055] Because the catadioptric optical system 40 uses polarized light, if the component lenses are made of resin, which has a lower specific gravity than glass, the polarization state will change and light rays will be generated that do not follow the normal optical path. These light rays will enter the eye as stray light and be perceived as double images or blurred images. For this reason, it is preferable that the lenses used in the catadioptric optical system 40 be made of glass, which has almost no birefringence.

[0056] On the other hand, the effect of birefringence can be ignored for elements in the optical path that do not use polarized light. As will be described in detail later, in the optical device 30, it is only necessary to convert the light into the required linearly polarized light by the reflective polarizer 62 provided on the light incident side of the catadioptric optical system 40. In other words, the optical path before the reflective polarizer 62 can be an optical path that uses non-polarized light, and if non-polarized light is used, no problems will occur even if a resin lens with birefringence is used for the lens 54. In other words, it is preferable that the lens 54 be made of resin.

[0057] For example, acrylic, polycarbonate, polyester, cycloolefin, etc. are known as resins used for lenses, and these can be typically used as the material for lens 54. Note that if a material with sufficiently small birefringence is used, a resin lens can also be used in catadioptric optical system 40.

[0058] In order for the optical path before the reflective polarizer 62 to be an optical path that utilizes unpolarized light, the light emitted by the light source must be unpolarized. In other words, a display panel that emits unpolarized light can be used as the display panel 20, which is the light source.

[0059] As a display panel that emits non-polarized light, for example, an organic EL panel having organic EL elements or an LED panel having micro LEDs can be used. In particular, it is preferable to use an organic EL panel that is self-luminous and can easily form a high-definition display unit. In this specification, a micro LED refers to a micro LED having a chip area of ​​10,000 μm or more. ２ The LED panel is not limited to micro LEDs, and may be, for example, a light-emitting diode with a chip area of ​​10,000 μm ２ Larger than 1mm ２ The following light-emitting diodes (also called mini-LEDs) may also be used: In this embodiment, an example using an organic EL panel will be described.

[0060] Generally, the light emitted from a liquid crystal panel is polarized, making it unsuitable for use as the display panel 20. Furthermore, because liquid crystal panels are non-emissive, they require a separate light source such as a backlight. Therefore, it can be said that using a self-emissive organic EL panel as the display panel 20 is advantageous in terms of promoting the miniaturization and weight reduction of electronic devices.

[0061] As mentioned above, the region of the lens 54 that functions as a convex lens can also have the function of magnifying the image on the display unit 21. Organic EL panels formed using semiconductor processing equipment such as IC chips can produce panels with high pixel densities of over 3000 ppi. However, due to the shot size of the exposure equipment used in the lithography process, panel sizes are limited to small sizes of around 1 inch diagonal. Therefore, optical equipment is required to have a larger magnification ratio.

[0062] To increase the magnification, it is effective to use a lens with a large curvature to refract light more strongly, but a lens with a large curvature may change the polarization state of light.

[0063] When polarized light is incident obliquely on an interface with different refractive indices (for example, the interface between air and a lens), the transmittance of s-polarized light, whose electric field oscillates perpendicular to the plane of incidence, and p-polarized light, whose electric field oscillates parallel to the plane of incidence, differs depending on the angle. When polarized light is incident at an angle close to perpendicular to the interface (near 0°), there is almost no difference between the two. However, as the angle increases, the difference between the two initially increases, as there exists a Brewster angle at which the transmittance of p-polarized light is 100%. In other words, since the ratio of s-polarized light to p-polarized light changes before and after transmission depending on the angle, the state of polarized light that is incident obliquely at a large angle on the interface changes.

[0064] Therefore, if a lens with a large curvature is used in the catadioptric optical system 40 that uses polarized light, stray light is likely to occur, just as in the case of using a resin lens with birefringence. Therefore, if you want to increase the overall magnification of the optical device 30, it is preferable to increase the curvature of the lens 54 provided in the optical path that does not use polarized light.

[0065] If only the magnification of the image is considered, a lens 54 can be provided between the catadioptric system 40 and the eye 10. If the lens diameter is the same, it can be said that it is easier to increase the magnification by bending the light closer to the eye 10. However, if the light is bent significantly by a lens, chromatic aberration is likely to occur, so if the light is to be bent in a similar manner, it is preferable to use a reflective surface that does not cause chromatic aberration.

[0066] Since the catadioptric system 40 has a reflective surface with positive power, it is preferable to place the catadioptric system 40 as close as possible to the eye 10. From this point of view, it can be said that it is preferable to place the lens 54 between the display panel 20 and the catadioptric system 40.

[0067] For the above reasons, it is preferable to install the lens 54 between the non-polarized light source and the catadioptric system 40. Furthermore, assuming that the lens 54 is installed between the non-polarized light source and the catadioptric system 40, it is preferable that the lens 54 be made of a lightweight resin, since the effect of birefringence can be ignored. Furthermore, since the light incident on the lens 54 is non-polarized light, not specifically polarized light, a lens with a large curvature and high magnification can be used. Furthermore, since the catadioptric system 40 uses polarized light, it is preferable to use a glass lens, which does not substantially exhibit birefringence. Therefore, the optical device of one embodiment of the present invention can achieve a reduced weight and an increased magnification while suppressing the generation of stray light.

[0068] 3 is a cross-sectional view illustrating the optical device 30, with a portion of the optical path indicated by a dashed line. The optical device 30 has two optical paths: an optical path LP1 using light A that passes through the half mirror 31, and an optical path LP2 using light B that is reflected by the half mirror 31. The upper optical path indicates the optical path LP1, and the lower optical path indicates the optical path LP2.

[0069] 4 is a diagram illustrating the light utilization efficiency of each optical path. The upper optical path shows optical path LP1, and the lower optical path shows optical path LP2. Note that in FIGS. 3 and 4, for clarity, some elements are shown separated from each other.

[0070] In many conventional catadioptric systems, only light corresponding to light A is utilized, and light corresponding to light B is lost. In the catadioptric system according to one aspect of the present invention, light B is effectively utilized, thereby improving the light utilization efficiency.

[0071] First, the optical path LP1 using the light A transmitted through the half mirror 31 will be described.

[0072] A portion of the light emitted from the display panel 20 (light source) passes through the lens 54, the reflective polarizer 62, the lens 32, the retardation plate 63, the half mirror 31, the retardation plate 33, and the lens 35, and is reflected by the reflective polarizer 34. The light reflected by the reflective polarizer 34 passes through the lens 35 and the retardation plate 33, and is reflected again by the half mirror 31. The light reflected by the half mirror 31 passes through the retardation plate 33, the lens 35, and the reflective polarizer 34, and is incident on the eye 10.

[0073] In this way, repeated reflection within the optical device 30 ensures a sufficient optical path length, making it possible to provide an optical system with a short focal length.

[0074] A display panel that emits unpolarized light can be used as the display panel 20. In this embodiment, an example will be described in which an organic EL panel having organic EL elements is used.

[0075] The reflective polarizer 62 reflects linearly polarized light whose vibration direction coincides with the reflection axis and transmits linearly polarized light whose vibration direction is perpendicular to the reflection axis. The axis perpendicular to the reflection axis is called the transmission axis. The reflective polarizer 62 may be, for example, a wire grid polarizer or a dielectric multilayer film.

[0076] The reflective polarizer 62 can transmit one linearly polarized light from light vibrating in all directions through 360°. Note that, in the following description, the transmission axis of the reflective polarizer 62 is assumed to be 0°, but 0° is not an absolute value but a reference value. In other words, the polarization plane of the linearly polarized light that passes through the reflective polarizer 62 is treated as 0°. Therefore, for example, 90° linearly polarized light in this embodiment refers to linearly polarized light whose polarization plane is rotated by 90° from the linearly polarized light that passes through the reflective polarizer 62.

[0077] 3 shows an example in which the reflective polarizer 62 is provided on one surface (convex surface) of the lens 32, which is a plano-convex lens. This contributes to the generation of an optical path LP2, which will be described later.

[0078] A convex lens can be used as the lens 32. While FIG. 3 shows an example in which a plano-convex lens is used as the lens 32, the present invention is not limited to this. For example, the lens 32 may be composed of a plurality of plano-convex lenses. Furthermore, the lens 32 may be a biconvex lens. Alternatively, the lens 32 may be composed of a combination of lenses selected from a biconvex lens, a plano-convex lens, a biconcave lens, a plano-concave lens, a convex meniscus lens, and a concave meniscus lens. Furthermore, the lens 32 is not limited to a spherical lens, and may also be an aspherical lens.

[0079] The lens 35 may be the same as the lens 32. The optical device 30 may be provided with lenses other than the lenses 32 and 35. Either the lens 32 or the lens 35 may not be provided. The lenses 32 and 35 may be provided in other positions.

[0080] In the optical path LP1, the lens 32 acts as a convex lens having a positive power, contributing to an improvement in the magnification ratio.

[0081] 3, it is preferable to use plano-convex lenses as the lenses 32 and 35, and to arrange them so that their flat surfaces face each other. This arrangement allows the thin retardation plate 63, the half mirror 31, and the retardation plate 33 to be sandwiched between the flat surfaces, making it possible to omit part of the support body. This also simplifies the manufacturing process.

[0082] The retardation plate 63 has a function of converting linearly polarized light into circularly polarized light. Here, a λ / 4 plate (¼ wavelength plate) is used as the retardation plate 63. When the reflective polarizer 62 and the λ / 4 plate are overlapped so that the slow axis of the λ / 4 plate is at 45° with respect to the axis of the linearly polarized light emitted from the reflective polarizer 62, right-handed circularly polarized light (right-handed circularly polarized light) is obtained. When the reflective polarizer 62 and the λ / 4 plate are overlapped so that the slow axis of the λ / 4 plate is at −45° with respect to the axis of the linearly polarized light emitted from the reflective polarizer 62, left-handed circularly polarized light (left-handed circularly polarized light) is obtained. In one embodiment of the present invention, either right-handed circularly polarized light or left-handed circularly polarized light may be used as long as the combination with the characteristics of the reflective polarizer 34 described below is appropriate.

[0083] For example, a metal film or a dielectric multilayer film can be used for the half mirror 31. The transmittance and reflectance of the half mirror 31 for visible light can be set to 40% or more and 60% or less, where T is the transmittance and (1-T) is the reflectance, and for example, each can be set to about 50%.

[0084] The retardation plate 33 has a function of reversibly converting linearly polarized light and circularly polarized light. As the retardation plate 33, a λ / 4 plate (¼ wavelength plate) can be used, similar to the retardation plate 63.

[0085] The reflective polarizer 34, like the reflective polarizer 62, can reflect linearly polarized light whose vibration direction coincides with the reflection axis and transmit linearly polarized light whose vibration direction is orthogonal to the reflection axis. The reflective polarizer 34 is disposed so that its transmission axis overlaps with the transmission axis of the reflective polarizer 62 and is orthogonal to it.

[0086] The light reflected by the reflective polarizer 34 is reflected by the planar half mirror 31 and travels so as to be converged toward the eye 10. Therefore, it is preferable that the reflective polarizer 34 has a positive power. For this reason, it is preferable that the reflective polarizer 34 has a curved surface with a concave surface facing the half mirror 31. Figure 3 shows an example in which the reflective polarizer 34 is provided on one surface of the lens 35, which is a plano-convex lens.

[0087] That is, in the optical path LP1, the lens 35, in combination with the reflective polarizer 34, acts as a concave mirror having a positive power, contributing to an improvement in the magnification ratio.

[0088] By using such an arrangement, an optical path can be established that reaches the eye 10 from the light source.

[0089] The polarization state in the optical path LP1 described above will be described in detail using the upper optical path shown in Fig. 3. Note that, although an example in which the light emitted from the retardation plate 63 is right-handed circularly polarized light will be described below, it may also be left-handed circularly polarized light.

[0090] The light emitted from the display panel 20 and vibrating in all directions by 360° passes through the lens 54 and is incident on the reflective polarizer 62. The transmission axis of the reflective polarizer 62 is 0°, and 0° linearly polarized light is emitted from the reflective polarizer 62.

[0091] The 0° linearly polarized light emitted from the reflective polarizer 62 passes through the lens 32 and is converted into right-handed circularly polarized light by the retarder 63. The right-handed circularly polarized light emitted from the retarder 63 passes through the half mirror 31 and is incident on the retarder 33, where it is converted into 0° linearly polarized light.

[0092] The 0° linearly polarized light emitted from the retardation plate 33 passes through the lens 35, is reflected by the reflective polarizer 34 with a reflection axis of 0°, and is incident on the retardation plate 33 via the lens 35, where it is converted into right-handed circularly polarized light.

[0093] The right-handed circularly polarized light emitted from the retardation plate 33 is reflected by the half mirror 31 and inverted into left-handed circularly polarized light. The left-handed circularly polarized light inverted by the half mirror 31 is incident on the retardation plate 33 and converted into 90° linearly polarized light. The 90° linearly polarized light emitted from the retardation plate 33 passes through the lens 35 and the reflective polarizer 34 with a transmission axis of 90°, and is incident on the eye 10.

[0094] In this way, by using linearly polarized light and circularly polarized light, as well as a half mirror and a reflective polarizer, it is possible to selectively reflect or transmit light, thereby ensuring the optical path length within a limited space and shortening the focal length of optical equipment.

[0095] Next, the light utilization efficiency of the optical path LP1 will be explained using the optical path shown in the upper part of Figure 4. Note that the unclear surface reflection and absorption of light and the collapse of polarization in each element are ignored here. Also, the transmittance of the lens 54 is assumed to be 100%, and the transmittance and reflectance of the half mirror 31 are each approximately 50%.

[0096] The theoretical transmittance of the reflective polarizer 62 is approximately 50% at maximum, but taking into account loss due to absorption, it is set to approximately 40% (0.4 times) here. Therefore, when the amount of light emitted from the display panel 20 in the direction of the optical device 30 is 1, the amount of light emitted from the reflective polarizer 62 is approximately 0.4 (1 x 0.4).

[0097] Furthermore, since the transmittance of the lens 32 and the retardation plate 63 is ideally 100% (1x), the amount of light emitted from the retardation plate 63 is approximately 0.4 (0.4 x 1).

[0098] Next, the light emitted from the phase difference plate 63 passes through the half mirror 31, but since the transmittance is about 50% (0.5 times), the amount of light after passing through the half mirror 31 is about 0.2 (0.4×0.5).

[0099] The light that has passed through the half mirror 31 passes through the retardation plate 33 and lens 35, is reflected by the reflective polarizer 34, passes through the lens 35 and retardation plate 33, and reaches and is reflected again by the half mirror 31. If the transmittance of the lens 35 and retardation plate 33 and the reflectance of the reflective polarizer 34 are ideally 100% (1x), and the reflectance of the half mirror 31 is approximately 50% (0.5x), the amount of light after reflection by the half mirror is approximately 0.1 (0.2 x 0.5).

[0100] The light then passes through each element arranged in the optical path, and because the transmittance of each element is ideally 100% (1x), the amount of light finally emitted from the reflective polarizer 34 is approximately 0.1.

[0101] As described above, the light utilization efficiency is very low with only the light path LP1, so it is necessary to increase the brightness of the light source. The reason for the low light utilization efficiency is mainly the loss in the half mirror. In one aspect of the present invention, it is possible to generate the light path LP2 that effectively utilizes the light B reflected by the half mirror 31.

[0102] Next, the optical path LP2 that utilizes the light B reflected by the half mirror 31 will be described using the lower optical path shown in FIG.

[0103] A portion of the light emitted from the display panel 20 (light source) passes through the reflective polarizer 62, the lens 32, and the retardation plate 63, and is reflected by the half mirror 31. The light reflected by the half mirror 31 passes through the retardation plate 63 and the lens 32, and is reflected by the reflective polarizer 62. The light reflected by the reflective polarizer 62 passes through the lens 32, the retardation plate 63, the half mirror 31, the retardation plate 33, the lens 35, and the reflective polarizer 34, and is incident on the eye 10.

[0104] In optical path LP2, lens 32 acts as a concave mirror with positive power in combination with reflective polarizer 62. Lens 35 acts as a convex lens with positive power. Both of these contribute to improving the magnification of catadioptric optical system 40.

[0105] In this way, the light B that was lost in the optical path LP1 can be effectively utilized, and the light utilization efficiency can be improved.

[0106] Next, the polarization state on the optical path LP2 will be described in detail.

[0107] The light emitted from the display panel 20 and vibrating in all directions at 360° passes through the lens 54 and is incident on the reflective polarizer 62. The transmission axis of the reflective polarizer 62 is 0°, and 0° linearly polarized light is emitted from the reflective polarizer 62. The 0° linearly polarized light emitted from the reflective polarizer 62 passes through the lens 32 and is converted into right-handed circularly polarized light by the retardation plate 63. Up to this point, the optical path is the same as that of the optical path LP1.

[0108] The right-handed circularly polarized light emitted from the phase difference plate 63 is reflected by the half mirror 31 and inverted into left-handed circularly polarized light. The left-handed circularly polarized light inverted by the half mirror 31 enters the phase difference plate 63 and is converted into 90° linearly polarized light.

[0109] The 90° linearly polarized light emitted from the retardation plate 63 passes through the lens 32 and enters the reflective polarizer 62. The reflection axis of the reflective polarizer 62 is 90°, and the light is reflected while maintaining its polarization state. The 90° linearly polarized light reflected by the reflective polarizer 62 enters the retardation plate 63 via the lens 32 and is converted into left-handed circularly polarized light. The left-handed circularly polarized light emitted from the retardation plate 63 passes through the half mirror 31 and enters the retardation plate 33, where it is converted into 90° linearly polarized light. The 90° linearly polarized light emitted from the retardation plate 33 passes through the lens 35 and the reflective polarizer 34, whose transmission axis is 90°, and enters the eye 10.

[0110] In this way, by using linearly polarized light and circularly polarized light, as well as a half mirror and a reflective polarizer, reflection and transmission can be selectively performed in the optical path LP2 as well, which makes it possible to ensure a sufficient optical path length within a limited space and shorten the focal length of the optical device.

[0111] Next, the light utilization efficiency in the light path LP2 will be described using the light path shown in the lower part of Fig. 4. The transmittance of the reflective polarizer 62 is approximately 40% (0.4 times), and when the amount of light emitted from the display panel 20 in the direction of the optical device 30 is set to 1, the amount of light emitted from the reflective polarizer 62 is approximately 0.4 (1 x 0.4).

[0112] Furthermore, since the transmittance of the lens 32 and the retardation plate 63 is ideally 100% (1x), the amount of light emitted from the retardation plate 63 is approximately 0.4 (0.4 x 1).

[0113] Next, the light emitted from the phase difference plate 63 is reflected by the half mirror 31, but since the reflectance is about 50% (0.5 times), the amount of light after reflection from the half mirror 31 is about 0.2 (0.4×0.5).

[0114] The light reflected by the half mirror 31 passes through the phase difference plate 63, is reflected by the reflective polarizer 62, and again reaches and passes through the half mirror 31. If the transmittance of the phase difference plate 63 and the reflectance of the reflective polarizer 62 are ideally 100% (1x), and the transmittance of the half mirror 31 is approximately 50% (0.5x), the amount of light after reflection by the half mirror is approximately 0.1 (0.2 x 0.5).

[0115] The light then passes through each element arranged in the optical path, and since the transmittance of each element is ideally 100% (1x), the amount of light finally emitted from the lens 35 is approximately 0.1.

[0116] As a result of the above, in optical device 30, the amount of light reaching eye 10 is 0.1 (optical path LP1) + 0.1 (optical path LP2) = 0.2, which allows for a higher light utilization efficiency than optical devices that use only light A or light B. Note that the above explanation of light utilization efficiency does not take into account unclear surface reflection, absorption, etc. in each element, and therefore the actual light utilization efficiency may be slightly less than approximately twice that of optical devices that use only light A or light B.

[0117] As described above, the optical device 30 can improve the light utilization efficiency, but the image formation positions of the optical paths LP1 and LP2 must be aligned to properly view the image displayed on the display panel 20. Specifically, the image formation position in the eye 10 is on the retina.

[0118] If the image formation positions on the retina are significantly misaligned, problems such as double images (double images) occur. While perfect alignment of the image formation positions of the two optical paths is preferable, misalignment within a range that does not affect visibility is acceptable. Specifically, a misalignment of up to 50% or less of overlap of light emitted from adjacent pixels on the display panel is acceptable. If the misalignment is 50% or less, the image is perceived with substantially the same resolution. However, if the misalignment is greater than 50%, the image is perceived with reduced resolution, and the image may appear blurred. Therefore, the range of image formation position alignment described in this embodiment includes not only perfect alignment but also misalignment of up to 50% or less of overlap of light emitted from adjacent pixels.

[0119] In order to align the imaging positions of optical paths LP1 and LP2 and to reduce aberrations in the optical system, it is preferable to have the optical characteristics of multiple elements interact with each other. In one aspect of the present invention, aberrations are reduced by the interaction of the optical characteristics of the reflective surfaces of the reflective polarizers 62 and 34, the lenses 32 and 35, and the lens 54 of the catadioptric optical system 40. In other words, the aberrations of the catadioptric optical system 40 are corrected by the lens 54.

[0120] Note that a reflective surface generally refers to the boundary surface when light is incident on a material with a different refractive index. However, light is not necessarily reflected only at the surface of the material. In components of optical devices, light may be reflected not only at the surface but also internally. In addition, the surface on the light incident side (front surface) may act as the first reflective surface, and the surface opposite to the light incident side (back surface) may act as the second reflective surface. In addition, there may be multiple reflective surfaces, such as in a multilayer film. Therefore, in this embodiment, the reflective surface may refer to the parts that reflect light collectively.

[0121] When light is incident on a flat surface, it undergoes refraction and reflection, but because the normal vector is uniform within the surface, it cannot focus or diffuse light like a lens. To focus or diffuse light, a curved surface is required, whose normal vector changes depending on the position. Lenses are an example of an element with a curved surface, and the use of multiple lenses with positive power makes it easier to focus light emitted from a light source onto the eye. However, in optical devices where thinness and light weight are desired, the use of multiple lenses is not desirable.

[0122] Therefore, it is preferable that the reflecting surface that generates the optical path also has a positive power like a concave mirror. Note that, since it is sufficient for the optical device as a whole to have the effect of focusing light onto the eye, it is sufficient that the optical device as a whole has a configuration with positive power, and it is also possible for some reflecting surfaces to have no positive power.

[0123] Furthermore, when light is focused using a curved surface, various aberrations occur depending on the shape of the curved surface, but these aberrations can be reduced through the interaction with the lens described above. Furthermore, for the same curvature, a reflective surface has greater power than a lens, and in principle, chromatic aberrations do not occur on reflective surfaces. Therefore, in order to efficiently focus or diffuse light, it is preferable to use a reflective surface with a curved surface in addition to a lens.

[0124] In the optical path LP1, the image position is determined by the interaction between the lens 32, the half mirror 31, the reflective polarizer 34, and the lens 35, with the contribution of the reflective polarizer 34 being particularly large. In addition, in the optical path LP2, the image position is determined by the interaction between the lens 32, the half mirror 31, the reflective polarizer 62, and the lens 35, with the contribution of the reflective polarizer 62 being particularly large.

[0125] Among the elements of the optical device 30, when the state (shape, position, etc.) of the half mirror 31, the lens 32, and the lens 35 changes, both the optical path LP1 and the optical path LP2 change. On the other hand, when the state of the reflective polarizer 34 changes, the optical path LP1 is significantly affected. Furthermore, when the state of the reflective polarizer 62 changes, the optical path LP2 is significantly affected.

[0126] Therefore, it is possible to easily align the image formation positions of the optical paths LP1 and LP2 by changing the states of the reflective polarizer 62 and the reflective polarizer 34. Specifically, it is effective to curve the reflective surfaces of the reflective polarizer 62 and the reflective polarizer 34.

[0127] Fig. 5 is a diagram illustrating elements having reflective surfaces effective for generating an optical path selected from Fig. 3. The reflective polarizer 62 has a reflective surface 62a on the half mirror 31 side. The half mirror 31 has a reflective surface 31a on the reflective polarizer 62 side and a reflective surface 31b on the reflective polarizer 34 side. The reflective polarizer 34 has a reflective surface 34a on the half mirror 31 side.

[0128] In Figure 5, for convenience, the surface is shown as a reflective surface, but as mentioned above, light may be reflected not only from the surface but also internally. In a thin film structure such as a half mirror, the reflection action can be said to occur over the entire thickness direction. In other words, the entire thickness direction can be called a reflective surface.

[0129] FIG. 5 shows an optical path from a light source origin S to an imaging position E, with a solid line indicating an example of an optical path LP1 and a dashed line indicating an example of an optical path LP2.

[0130] The optical path LP1 has a path that passes through the reflective polarizer 62 and the half mirror 31, turns around the reflective surface 34a of the reflective polarizer 34, turns around the reflective surface 31b of the half mirror 31, and passes through the reflective polarizer 34.

[0131] The optical path LP2 has a path that passes through the reflective polarizer 62, turns around the reflective surface 31a of the half mirror 31, turns around the reflective surface 62a of the reflective polarizer 62, and passes through the half mirror 31 and the reflective polarizer .

[0132] Although the optical paths LP1 and LP2 are shown separated for clarity, they are paths through which light emitted from the same starting point forms an image at the same end point, although the paths are partially different. In other words, light emitted in the same direction from the same position on the light source travels along optical path LP1 or optical path LP2 and forms an image at the same position after passing through the reflective polarizer 34.

[0133] In the optical path LP1, when the effective reflective surface 31b of the half mirror 31 is flat, the reflective surface 31a is usually flat. When using the half mirror 31 having such a shape, it is effective to make the reflective surfaces of the reflective polarizer 62 and the reflective polarizer 34 curved as described above in order to easily align the image positions of the optical paths LP1 and LP2.

[0134] It has been confirmed through simulations using Synopsys' optical design and analysis software CODE V that the imaging positions of the optical paths LP1 and LP2 can be aligned by forming the reflecting surfaces 62a and 34a as concave curved surfaces.

[0135] Here, the configuration of the catadioptric optical system 40 will be described in more detail. A thin metal film or a dielectric multilayer film is used for the half mirror 31. The metal film or the dielectric multilayer film is generally formed by depositing it on a support using a method such as vapor deposition. Therefore, although not shown in FIGS. 1, 3, and 4, a support is provided between the half mirror 31 and either the retardation plate 63 or the retardation plate 33. The support is preferably made of glass or resin that has high translucency to visible light.

[0136] When there is a difference in refractive index between the optical paths before and after the half mirror 31, transmitted light other than that incident perpendicularly is refracted. If the light passing through the half mirror 31 is polarized light, the polarization state may be disrupted by refraction, making it more likely that stray light will occur.

[0137] Therefore, it is preferable to eliminate or reduce the difference in refractive index in the optical path before and after the half mirror 31. To obtain such optical characteristics, it is effective to sandwich the half mirror 31 between materials that are the same material or have a small difference in refractive index.

[0138] In other words, the support bodies La and Lb may be made of the same material or materials with a small difference in refractive index, and the half mirror 31 may be sandwiched between the support bodies La and Lb, as shown in Fig. 6A. The support bodies La and Lb are preferably made of a material with high visible light transmittance and small birefringence. A typical example of such a material is glass.

[0139] With this configuration, the light passing through the half mirror 31 can travel almost straight. Alternatively, the refraction of the light passing through the half mirror 31 can be reduced. Therefore, the generation of stray light due to refraction can be suppressed.

[0140] Furthermore, the catadioptric optical system 40 according to one embodiment of the present invention is configured to approximately double the light utilization efficiency by aligning the image formation positions of the optical paths LP1 and LP2. This is possible because the two split beams of light are refracted or reflected in the same way along the paths of the optical paths LP1 and LP2, and the two optical paths ultimately overlap. To achieve this effect, it is preferable to use an optical system that is symmetrical with respect to the flat half mirror 31.

[0141] A symmetrical optical system is an optical system in which a plurality of optical elements are arranged in plane symmetry with respect to a reference plane of symmetry, and a pair of plane-symmetric optical elements have the same optical characteristics.

[0142] The layer functioning as the half mirror 31 is in the form of a film or a thin film, and is therefore usually provided on a support (for example, a flat support La or support Lb shown in FIG. 6A). Fig. 7A is a simplified diagram of Fig. 3, adding the support L of the half mirror 31, and shows optical paths LP1 and LP2.

[0143] In this way, when the half mirror 31 is provided on the support L, the presence of the support L causes the optical paths LP1 and LP2 to become asymmetric, and unless an element is provided to correct one of the optical paths, a misalignment will occur between the two.

[0144] 7A and the action of each element on the incident light, starting from the display panel 20 side. Note that an arrow in the table indicates that there is no corresponding element.

[0145]

[0146] From Table 1, it can be seen that the light path LP1 passes through the support L two times more than the light path LP2. In other words, in the optical system shown in FIG. 7A, the light paths LP1 and LP2 can be said to be asymmetric.

[0147] Furthermore, the symmetry is further broken when the relative positions of the reflective polarizer 34 and the reflective polarizer 62 with respect to the half mirror 31 differ, or when the relative positions of the retardation plates 33 and 63 with respect to the half mirror 31 differ. Similarly, the symmetry is broken when the optical characteristics of the reflective polarizer 34 and the reflective polarizer 62 differ, or when the optical characteristics of the retardation plates 33 and 63 differ.

[0148] In this way, the misalignment of the optical paths due to the asymmetry between the optical paths LP1 and LP2 changes the image formation position, which may result in double images and a decrease in display quality. Note that it is possible to perform optical design so that the optical paths LP1 and LP2 are imaged at the same position, taking into account the asymmetry between the optical paths LP1 and LP2. However, optical design is easier if the optical paths LP1 and LP2 are symmetrical.

[0149] 6A , it is preferable that the supports (supports La, support Lb), retardation plates (retardation plates 63, retardation plates 33), and reflective polarizers (reflective polarizers 62, reflective polarizers 34) are configured to be plane-symmetric with respect to the flat plate-shaped half mirror 31. It is also preferable that the reflective polarizers 34 and 62 have the same optical characteristics, and that the retardation plates 33 and 63 also have the same optical characteristics. It is also preferable that the supports La and Lb have the same optical characteristics.

[0150] In reality, the half mirror 31 has a thickness and has a first surface and a second surface opposite to the first surface. Therefore, the plane of symmetry of the half mirror 31 can be considered to be parallel to the first surface and the second surface and located at half the position in the thickness direction.

[0151] Fig. 7B is a diagram showing optical paths LP1 and LP2 when the configuration shown in Fig. 6A is used. Table 2 shows the elements located on the optical paths shown in Fig. 7B and the functions of each element, starting from the display panel 20 side.

[0152]

[0153] As shown in FIG. 7B and Table 2, in optical path LP1, the light passes through the support a total of four times (an increase of one time). Also, in optical path LP2, the light passes through the support a total of four times (an increase of three times). Since the other elements and their actions are the same as in FIG. 7A and Table 1, it can be said that optical paths LP1 and LP2 are symmetrical. In other words, the configuration shown in FIG. 6A can be said to be suitable for aligning the imaging positions of optical paths LP1 and LP2.

[0154] 6A, the half mirror 31 is sandwiched between supports by, for example, first forming the half mirror 31 on the support La by using a vapor deposition method or the like, and then providing the support Lb on the half mirror 31.

[0155] At this time, it is preferable to bond the half mirror 31 and the support Lb via an adhesive layer to obtain mechanical strength. Also, to increase the mechanical strength of the entire catadioptric optical system 40, it is preferable to provide adhesive layers (adhesive layers 55a to 55g) between adjacent elements of some other elements as well, as shown in Figure 6B.

[0156] As mentioned above, it is most preferable in terms of optical characteristics that the catadioptric system 40 has a symmetrical structure with the half mirror 31 as the plane of symmetry, but an adhesive layer 55d, which is not present between the support La and the half mirror 31, is provided between the support Lb and the half mirror 31. Therefore, it can be seen that this structure cannot be said to be a symmetrical structure in the strict sense.

[0157] Therefore, to achieve a substantially symmetrical structure, first, an optical adhesive having a refractive index equivalent to that of the support La and the support Lb is used for the adhesive layer 55d. Then, the refractive index of the support Lb is set to n Ｌｂ , thickness is T Ｌｂ The refractive index of the support La is n Ｌａ , thickness is T Ｌａ and the refractive index of the adhesive layer 55b is n ５５ , thickness is T ５５ When this is the case, n Ｌａ ×T Ｌａ = n Ｌｂ ×T Ｌｂ +n ５５ ×T ５５In this way, by taking into account the optical path length (refractive index x thickness) of the adhesive layer 55d, it is possible to make the optical path lengths on both sides of the half mirror 31 at the center equal. In other words, it is possible to improve the symmetry of the optical path.

[0158] In addition, Figure 6A shows an example in which a unit having a half mirror 31 between support La and support Lb is at the center, a phase difference plate 63 is provided between support La and lens 32, and a phase difference plate 33 is provided between support Lb and lens 35, but this is not limited to this.

[0159] 8A , a unit having a half mirror 31 between supports La and Lb may be placed at the center, and a lens 32 may be provided between the support La and a retardation plate 63, and a lens 35 may be provided between the support Lb and the retardation plate 33. In this configuration, a reflective polarizing plate 62 is provided outside the retardation plate 63, and a reflective polarizing plate 34 is provided outside the retardation plate 33.

[0160] In this modified example of the configuration, lens 32 can be used instead of support La, and lens 35 can be used instead of support Lb. In other words, support La and support Lb can be omitted. Therefore, manufacturing steps such as a bonding step using an adhesive can be reduced.

[0161] 8B , a unit having a half mirror 31 between supports La and Lb may be placed at the center, and a retardation plate 63 may be provided between support La and a reflective polarizing plate 62, and a retardation plate 33 may be provided between support Lb and a reflective polarizing plate 34. In this configuration, a lens 32 is provided outside the reflective polarizing plate 62, and a lens 35 is provided outside the reflective polarizing plate 34.

[0162] In this configuration, the reflective polarizers 62 to 34 can be sandwiched between the planar sides of the lenses 32 and 35, which are plano-convex lenses, and therefore the manufacturing process can be simplified.

[0163] 9A is a block diagram illustrating a display panel 20 included in an electronic device of one embodiment of the present invention. The display panel 20 includes a pixel array 74, a circuit 75, and a circuit 76. The pixel array 74 includes pixels 70 arranged in columns and rows.

[0164] The pixel 70 can have a plurality of 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, a full-color display can be achieved.

[0165] The subpixel 71 has a light-emitting device that emits unpolarized visible light. As the light-emitting device, it is preferable to use an EL element such as an OLED (organic light-emitting diode) or a QLED (quantum-dot light-emitting diode). Examples of light-emitting materials that the EL element has include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescence (TADF) materials, and inorganic compounds (quantum dot materials). Alternatively, an LED such as a micro LED can be used as the light-emitting device.

[0166] The circuit 75 and the circuit 76 are driver circuits for driving the sub-pixel 71. The circuit 75 can function as a source driver circuit, and the circuit 76 can function as a gate driver circuit. The circuits 75 and 76 can be, for example, shift register circuits.

[0167] The display panel may be divided into a plurality of regions vertically and horizontally, and pixels may be driven for each divided region.

[0168] 9B , the circuit 75 and the circuit 76 can be separately disposed below the pixel array 74. In this case, the display panel 20 has a laminated structure of a layer 77 and a layer 78, and a plurality of the circuits 75 and a plurality of the circuits 76 are provided on the layer 77, and the pixel array 74 is provided on the layer 78 so as to overlap the circuits 75 and the circuits 76.

[0169] By dividing the circuit 75 and the circuit 76, the pixel array 74 can be driven for each divided area. For example, the pixel array 74 can be operated at different frame rates in parts. The pixel array 74 can be displayed at different resolutions in parts, and can also be made compatible with foveated rendering.

[0170] Furthermore, by providing the driver circuit below the pixel array 74, the wiring length can be shortened and the wiring capacitance can be reduced. This allows for a display panel that can operate at high speed and with low power consumption. Furthermore, the display panel 20 can have a narrow frame.

[0171] 9B are merely examples and may be changed as appropriate. Part of the circuit 75 and part of the circuit 76 may be formed on the same layer as the pixel array 74. The layer 77 may also include circuits such as a memory circuit, an arithmetic circuit, and a communication circuit.

[0172] In this structure, for example, the layer 77 is provided on a single crystal silicon substrate, the circuits 75 and 76 are formed using transistors having silicon in their channel formation regions (hereinafter referred to as Si transistors), and the pixel circuits included in the pixel array 74 provided in the layer 78 are formed using transistors having metal oxide in their channel formation regions (hereinafter referred to as OS transistors). The OS transistor can be formed using a thin film and can be stacked on the Si transistor.

[0173] 9C , a structure may be adopted in which a layer 79 including an OS transistor is provided between the layer 77 and the layer 78. The layer 79 may include an OS transistor that forms part of a pixel circuit included in the pixel array 74. Alternatively, the layer 79 may include an OS transistor that forms part of the circuit 75 and the circuit 76. Alternatively, the layer 77 may include an OS transistor that forms part of a circuit such as a memory circuit, an arithmetic circuit, or a communication circuit.

[0174] The shape of the top surface of the display panel 20 is not limited to a rectangle, but may be a circle as shown in Fig. 9D, or a polygon such as an octagon as shown in Fig. 9E.

[0175] 10A and 10B are diagrams showing an example of a glasses-type device having the display panel 20 and optical device 30 shown in Fig. 1. Here, the combination of the display panel 20 and the optical device 30 is shown by dashed lines as a display unit 92. The glasses-type device has two sets of display units 92, and may be called VR glasses or the like depending on the application.

[0176] The two display units 92 are incorporated into the housing 90 so that the surfaces of the lenses 35 are exposed on the inside. One display unit 92 is for the right eye, and the other display unit 92 is for the left eye, and by displaying images corresponding to the parallax on each display unit 92, the user can feel the three-dimensionality of the image.

[0177] Furthermore, the housing 90 or the band 91 may be provided with an input terminal and an output terminal. The input terminal can be connected to a cable for supplying a video signal from a video output device or the like, or for supplying power for charging a battery provided within the housing 90. The output terminal functions as, for example, an audio output terminal, and can be connected to earphones, headphones, or the like. Note that if the configuration is such that audio data can be output via wireless communication, or if audio is output from an external video output device, the audio output terminal need not be provided.

[0178] Furthermore, a wireless communication module and a storage module may be provided inside the housing 90 or the band 91. The wireless communication module performs wireless communication, and the content to be viewed can be downloaded and stored in the storage module. This allows the user to view the downloaded content offline.

[0179] A line-of-sight detection sensor may also be provided inside the housing 90. For example, operation buttons such as power on, power off, sleep, volume adjustment, channel change, menu display, selection, decision, and back, as well as operation buttons such as video playback, stop, pause, fast forward, and fast rewind, can be displayed, and each operation can be performed by visually recognizing the operation button.

[0180] By using the optical device 30 of one embodiment of the present invention for a glasses-type device, the electronic device can be small, thin, low in power consumption, and highly reliable.

[0181] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes and examples described in this specification.

[0182] In this embodiment, a structure example of a display panel that can be applied to an electronic device of one embodiment of the present invention will be described. The display panel exemplified below can be applied to the display panel 20 in Embodiment 1.

[0183] One embodiment of the present invention is a display panel having light-emitting elements (also referred to as light-emitting devices). The display panel has two or more pixels that emit light of different colors. Each pixel has a light-emitting element. Each light-emitting element has a pair of electrodes and an EL layer therebetween. The light-emitting element is preferably an organic EL element (organic electroluminescent element). Two or more light-emitting elements that emit light of different colors each have an EL layer containing a different light-emitting material. For example, a full-color display panel can be realized by having three types of light-emitting elements that emit red (R), green (G), or blue (B) light, respectively.

[0184] When fabricating a display panel with multiple light-emitting elements that emit different colors of light, it is necessary to form at least one layer containing a light-emitting material (light-emitting layer) in an island shape. To fabricate part or all of the EL layer separately, a method for forming island-shaped organic films by vapor deposition using a shadow mask such as a metal mask is known. However, this method can result in deviations from the design in the shape and position of the island-shaped organic film due to various factors, such as the accuracy of the metal mask, misalignment between the metal mask and the substrate, metal mask deflection, and spreading of the contours of the deposited film due to vapor scattering, making it difficult to achieve high-resolution and high-aperture display panels. Furthermore, during vapor deposition, the contours of the layer can become blurred, resulting in thinning of the edges. In other words, the thickness of the island-shaped light-emitting layer can vary depending on the location. Furthermore, when fabricating large, high-resolution, or high-definition display panels, there is a concern that low dimensional accuracy of the metal mask and deformation due to heat can reduce manufacturing yield. Therefore, measures have been taken to artificially increase the resolution (also known as pixel density) by adopting special pixel arrangements such as a pentile array.

[0185] In this specification, the term "island-like" refers to a state in which two or more layers formed using the same material in the same process are physically separated. For example, an island-like light-emitting layer refers to a state in which the light-emitting layer is physically separated from an adjacent light-emitting layer.

[0186] In one embodiment of the present invention, an EL layer is processed into a fine pattern by photolithography without using a shadow mask such as a fine metal mask (FMM). This makes it possible to realize a display panel with high definition and a large aperture ratio, which have been difficult to achieve until now. Furthermore, because the EL layer can be individually fabricated, a display panel with extremely vivid images, high contrast, and high display quality can be realized. For example, the EL layer may be processed into a fine pattern by using both a metal mask and photolithography.

[0187] Furthermore, the EL layer can be partially or entirely separated physically. This can suppress leakage current between light-emitting elements via a layer shared between adjacent light-emitting elements (also referred to as a common layer). This can prevent light emission due to unintended crosstalk, thereby realizing a display panel with extremely high contrast. In particular, a display panel with high current efficiency at low luminance can be realized.

[0188] One embodiment of the present invention can also be a display panel that combines a white-emitting light-emitting element and a color filter. In this case, light-emitting elements provided in pixels (subpixels) that emit light of different colors can have the same structure, and all layers can be common layers. Furthermore, part or all of each EL layer can be separated by a process using photolithography. This suppresses leakage current through the common layer, thereby achieving a display panel with high contrast. In particular, in an element having a tandem structure in which multiple light-emitting layers are stacked via a highly conductive intermediate layer, leakage current through the intermediate layer can be effectively prevented, thereby achieving a display panel that combines high brightness, high definition, and high contrast.

[0189] When the EL layer is processed using photolithography, a portion of the light-emitting layer may be exposed, which may cause deterioration. Therefore, it is preferable to provide an insulating layer that covers at least the side surfaces of the island-shaped light-emitting layer. The insulating layer may also be configured to cover a portion of the top surface of the island-shaped EL layer. The insulating layer is preferably made of a material that has barrier properties against water and oxygen. For example, an inorganic insulating film that is less likely to diffuse water or oxygen can be used. This suppresses deterioration of the EL layer and realizes a highly reliable display panel.

[0190] Furthermore, there is a region (recess) between two adjacent light-emitting elements where the EL layer of either light-emitting element is not provided. When a common electrode, or a common electrode and a common layer, is formed to cover the recess, a phenomenon in which the common electrode is separated by a step at the edge of the EL layer (also called a step discontinuity) may occur, resulting in insulation of the common electrode on the EL layer. Therefore, it is preferable to use a configuration in which the local step located between two adjacent light-emitting elements is filled with a resin layer functioning as a planarizing film (also called LFP: Local Filling Planarization). The resin layer functions as a planarizing film. This suppresses step discontinuity in the common layer or common electrode, thereby achieving a highly reliable display panel.

[0191] A more specific example of the structure of a display panel according to one embodiment of the present invention will be described below with reference to the drawings.

[0192] 11A is a schematic top view of a display panel 100 according to one embodiment of the present invention. The display panel 100 includes a plurality of light-emitting elements 110R that exhibit red light, a plurality of light-emitting elements 110G that exhibit green light, and a plurality of light-emitting elements 110B that exhibit blue light over a substrate 101. In FIG. 11A , the light-emitting regions of the light-emitting elements are labeled with R, G, and B to easily distinguish the light-emitting elements from one another.

[0193] The light emitting elements 110R, 110G, and 110B are arranged in a matrix. Fig. 11A shows a so-called stripe arrangement in which light emitting elements of the same color are arranged in one direction. Note that the arrangement method of the light emitting elements is not limited to this, and arrangement methods such as an S-stripe arrangement, a delta arrangement, a Bayer arrangement, or a zigzag arrangement may also be used, or a pentile arrangement, a diamond arrangement, or the like may also be used.

[0194] It is preferable to use, for example, an organic light-emitting diode (OLED) or a quantum-dot light-emitting diode (QLED) as the light-emitting element 110R, the light-emitting element 110G, and the light-emitting element 110B. As the light-emitting substance contained in the EL element, not only an organic compound but also an inorganic compound (such as a quantum dot material) can be used.

[0195] 11A also shows a connection electrode 111C that is electrically connected to the common electrode 113. The connection electrode 111C is given a potential (e.g., an anode potential or a cathode potential) to be supplied to the common electrode 113. The connection electrode 111C is provided outside the display area where the light-emitting elements 110R and the like are arranged.

[0196] The connection electrode 111C can be provided along the periphery of the display area. For example, it may be provided along one side of the periphery of the display area, or it may be provided over two or more sides of the periphery of the display area. That is, when the top surface shape of the display area is rectangular, the top surface shape of the connection electrode 111C can be a strip shape (rectangle), an L-shape, a U-shape (square bracket shape), a square shape, or the like. In this specification, the top surface shape refers to the shape in a plan view, that is, the shape when viewed from above.

[0197] 11B and 11C are schematic cross-sectional views corresponding to dashed dotted lines A1-A2 and A3-A4 in Fig. 11A, respectively. Fig. 11B shows a schematic cross-sectional view of light-emitting element 110R, light-emitting element 110G, and light-emitting element 110B, and Fig. 11C shows a schematic cross-sectional view of connection portion 140 where connection electrode 111C and common electrode 113 are connected.

[0198] The light-emitting element 110R has a pixel electrode 111R, an organic layer 112R, a common layer 114, and a common electrode 113. The light-emitting element 110G has a pixel electrode 111G, an organic layer 112G, a common layer 114, and a common electrode 113. The light-emitting element 110B has a pixel electrode 111B, an organic layer 112B, a common layer 114, and a common electrode 113. The common layer 114 and the common electrode 113 are provided in common to the light-emitting element 110R, the light-emitting element 110G, and the light-emitting element 110B.

[0199] The organic layer 112R of the light-emitting element 110R contains a light-emitting organic compound that emits at least red light. The organic layer 112G of the light-emitting element 110G contains a light-emitting organic compound that emits at least green light. The organic layer 112B of the light-emitting element 110B contains a light-emitting organic compound that emits at least blue light. The organic layer 112R, the organic layer 112G, and the organic layer 112B can also be called EL layers, and each contains at least a layer containing a light-emitting substance (light-emitting layer).

[0200] Hereinafter, when describing matters common to light emitting element 110R, light emitting element 110G, and light emitting element 110B, they may be referred to as light emitting element 110. Similarly, when describing matters common to components distinguished by alphabets, such as organic layer 112R, organic layer 112G, and organic layer 112B, they may be described using symbols without the alphabets.

[0201] The organic layer 112 and the common layer 114 can each independently have one or more of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. For example, the organic layer 112 can have a stacked structure of a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer from the pixel electrode 111 side, and the common layer 114 can have an electron injection layer.

[0202] The pixel electrode 111R, pixel electrode 111G, and pixel electrode 111B are provided for each light-emitting element. The common electrode 113 and common layer 114 are provided as a continuous layer common to each light-emitting element. A conductive film transmissive to visible light is used for either the pixel electrode or the common electrode 113, and a conductive film reflective to visible light is used for the other. By making each pixel electrode transmissive and the common electrode 113 reflective, a bottom-emission display panel can be achieved. Conversely, by making each pixel electrode reflective and the common electrode 113 transmissive, a top-emission display panel can be achieved. Note that by making both the pixel electrodes and the common electrode 113 transmissive, a dual-emission display panel can be achieved.

[0203] A protective layer 121 is provided on the common electrode 113 to cover the light emitting elements 110R, 110G, and 110B. The protective layer 121 has a function of preventing impurities such as water from diffusing from above into each light emitting element.

[0204] The edge of the pixel electrode 111 preferably has a tapered shape. When the edge of the pixel electrode 111 has a tapered shape, the organic layer 112 provided along the edge of the pixel electrode 111 can also have a tapered shape. By tapering the edge of the pixel electrode 111, the coverage of the organic layer 112 provided over the edge of the pixel electrode 111 can be improved. Furthermore, by tapering the side surface of the pixel electrode 111, foreign matter (for example, also referred to as dust or particles) during the manufacturing process can be easily removed by a process such as cleaning, which is preferable.

[0205] In this specification and the like, the term "tapered shape" refers to a shape in which at least a part of a side surface of a structure is inclined with respect to a substrate surface. For example, it is preferable that the structure has a region in which the angle between the inclined side surface and the substrate surface (also referred to as the taper angle) is less than 90°.

[0206] The organic layer 112 is processed into an island shape using photolithography. As a result, the angle between the top surface and the side surface of the organic layer 112 at its edge is close to 90 degrees. On the other hand, an organic film formed using FMM (Fine Metal Mask) or the like tends to become gradually thinner closer to the edge. For example, the top surface is formed in a sloped shape over a range of 1 μm to 10 μm, making it difficult to distinguish between the top surface and the side surface.

[0207] Between two adjacent light emitting elements, there are an insulating layer 125, a resin layer 126 and a layer 128.

[0208] Between two adjacent light-emitting elements, the side surfaces of the organic layers 112 face each other with the resin layer 126 sandwiched therebetween. The resin layer 126 is located between the two adjacent light-emitting elements and is provided so as to fill the ends of each organic layer 112 and the region between the two organic layers 112. The resin layer 126 has a smooth, convex upper surface, and a common layer 114 and a common electrode 113 are provided to cover the upper surface of the resin layer 126.

[0209] The resin layer 126 functions as a planarizing film that fills in 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 end of the organic layer 112 (also called step disconnection), which would otherwise occur and result in insulation of the common electrode on the organic layer 112.

[0210] An insulating layer containing an organic material can be suitably used as the resin layer 126. For example, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin, precursors of these resins, etc. can be used as the resin layer 126. Alternatively, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used as the resin layer 126.

[0211] Furthermore, a photosensitive resin can be used as the resin layer 126. A photoresist can be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0212] The resin layer 126 may contain a material that absorbs visible light. For example, the resin layer 126 itself may be made of a material that absorbs visible light, or the resin layer 126 may contain a pigment that absorbs visible light. For example, the resin layer 126 may be a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light, or a resin that contains carbon black as a pigment and functions as a black matrix.

[0213] The insulating layer 125 is provided in contact with the side surface of the organic layer 112. The insulating layer 125 is also provided to cover the upper end portion of the organic layer 112. A portion of the insulating layer 125 is provided in contact with the upper surface of the substrate 101.

[0214] The insulating layer 125 is located between the resin layer 126 and the organic layer 112, and functions as a protective film to prevent the resin layer 126 from contacting the organic layer 112. If the organic layer 112 and the resin layer 126 come into contact with each other, the organic layer 112 may be dissolved by an organic solvent or the like used when forming the resin layer 126. Therefore, by providing the insulating layer 125 between the organic layer 112 and the resin layer 126, it is possible to protect the side surfaces of the organic layer 112.

[0215] The insulating layer 125 can be an insulating layer containing an inorganic material. For example, an inorganic insulating film such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film can be used for the insulating layer 125. The insulating layer 125 may have a single-layer structure or a stacked-layer structure. Examples of oxide insulating films include a silicon oxide film, an aluminum oxide film, a magnesium oxide film, an indium gallium zinc oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, and a tantalum oxide film. Examples of nitride insulating films include a silicon nitride film and an aluminum nitride film. Examples of oxynitride insulating films include a silicon oxynitride film and an aluminum oxynitride film. Examples of nitride oxide insulating films include a silicon nitride oxide film and an aluminum nitride oxide film. In particular, by using an inorganic insulating film such as a metal oxide film, an aluminum oxide film, or a silicon oxide film formed by an ALD method as the insulating layer 125, an insulating layer 125 with few pinholes and excellent protection of the EL layer can be formed.

[0216] In this specification and elsewhere, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0217] The insulating layer 125 can be formed by a sputtering method, a CVD method, a PLD method, an ALD method, or the like. The insulating layer 125 is preferably formed by an ALD method because it has good coverage.

[0218] Furthermore, a reflective film (e.g., a metal film containing one or more selected from silver, palladium, copper, titanium, aluminum, etc.) may be provided between the insulating layer 125 and the resin layer 126, so that the light emitted from the light-emitting layer is reflected by the reflective film, thereby improving the light extraction efficiency.

[0219] The layer 128 is a remaining portion of a protective layer (also referred to as a mask layer or a sacrificial layer) for protecting the organic layer 112 during etching of the organic layer 112. The layer 128 can be made of a material that can be used for the insulating layer 125. In particular, it is preferable to use the same material for the layer 128 and the insulating layer 125 because a common processing device or the like can be used for both.

[0220] In particular, inorganic insulating films such as metal oxide films such as aluminum oxide films and hafnium oxide films, or silicon oxide films formed by the ALD method have few pinholes and therefore have an excellent function of protecting the EL layer, and can be suitably used for the insulating layer 125 and the layer 128.

[0221] The protective layer 121 may have, for example, a single-layer structure or a stacked structure including at least an inorganic insulating film. Examples of the inorganic insulating film include oxide films or nitride films such as a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, an aluminum oxynitride film, and a hafnium oxide film. Alternatively, the protective layer 121 may be made of a semiconductor material or a conductive material such as indium gallium oxide, indium zinc oxide, indium tin oxide, or indium gallium zinc oxide.

[0222] The protective layer 121 may also be a laminated film of an inorganic insulating film and an organic insulating film. For example, a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films is preferable. Furthermore, it is preferable that the organic insulating film functions as a planarizing film. This allows the upper surface of the organic insulating film to be flat, improving the coverage of the inorganic insulating film thereon and enhancing the barrier properties. Furthermore, since the upper surface of the protective layer 121 is flat, when a structure (e.g., a color filter, a touch sensor electrode, a lens array, etc.) is provided above the protective layer 121, the influence of uneven shapes caused by the structure below can be reduced, which is preferable.

[0223] 11C shows a connection portion 140 where the connection electrode 111C and the common electrode 113 are electrically connected. In the connection portion 140, an opening is provided in the insulating layer 125 and the resin layer 126 above the connection electrode 111C. The connection electrode 111C and the common electrode 113 are electrically connected through the opening.

[0224] 11C shows a connection portion 140 where the connection electrode 111C and the common electrode 113 are electrically connected, but the common electrode 113 may be provided on the connection electrode 111C via the common layer 114. In particular, when a carrier injection layer is used for the common layer 114, the electrical resistivity of the material used for the common layer 114 is sufficiently low and the common layer 114 can be formed thin, so there are many cases where no problem occurs even if the common layer 114 is located at the connection portion 140. This allows the common electrode 113 and the common layer 114 to be formed using the same shielding mask, thereby reducing manufacturing costs.

[0225] [Configuration Example 2] The following describes a display panel having a configuration that is partially different from that of the above-described configuration example 1. Note that parts common to the above-described configuration example 1 will be referred to, and descriptions thereof may be omitted.

[0226] 12A shows a schematic cross-sectional view of the display panel 100a. The display panel 100a differs from the display panel 100 mainly in that the light-emitting elements have a different configuration and that the display panel 100a has colored layers.

[0227] The display panel 100a includes a light-emitting element 110W that emits white light. The light-emitting element 110W includes a pixel electrode 111, an organic layer 112W, a common layer 114, and a common electrode 113. The organic layer 112W emits white light. For example, the organic layer 112W may be configured to include two or more light-emitting materials whose emitted light colors are complementary to each other. For example, the organic layer 112W may be configured to include a light-emitting organic compound that emits red light, a light-emitting organic compound that emits green light, and a light-emitting organic compound that emits blue light. Alternatively, the organic layer 112W may be configured to include a light-emitting organic compound that emits blue light and a light-emitting organic compound that emits yellow light.

[0228] The organic layers 112W are separated between two adjacent light-emitting elements 110W. This makes it possible to suppress leakage current flowing between adjacent light-emitting elements 110W via the organic layers 112W, thereby suppressing crosstalk caused by the leakage current. As a result, a display panel with high contrast and color reproducibility can be realized.

[0229] An insulating layer 122 that functions as a planarizing film is provided on the protective layer 121, and a coloring layer 116R, a coloring layer 116G, and a coloring layer 116B are provided on the insulating layer 122.

[0230] The insulating layer 122 can be an organic resin film or an inorganic insulating film with a flattened upper surface. The insulating layer 122 forms the surface on which the colored layers 116R, 116G, and 116B are formed, and therefore, a flat upper surface of the insulating layer 122 allows the thickness of the colored layers 116R and the like to be uniform, thereby improving color purity. However, if the thickness of the colored layers 116R and the like is uneven, the amount of light absorption varies depending on the location of the colored layer 116R, which may result in a decrease in color purity.

[0231] Configuration Example 3 FIG. 12B shows a schematic cross-sectional view of a display panel 100b.

[0232] The light-emitting element 110R has a pixel electrode 111, a conductive layer 115R, an organic layer 112W, and a common electrode 113. The light-emitting element 110G has a pixel electrode 111, a conductive layer 115G, an organic layer 112W, and a common electrode 113. The light-emitting element 110B has a pixel electrode 111, a conductive layer 115B, an organic layer 112W, and a common electrode 113. The conductive layer 115R, the conductive layer 115G, and the conductive layer 115B each have light-transmitting properties and function as an optical adjustment layer.

[0233] A microresonator (microcavity) structure can be realized by using a film that reflects visible light for the pixel electrode 111 and a film that is both reflective and transparent to visible light for the common electrode 113. In this case, by adjusting the thicknesses of the conductive layers 115R, 115G, and 115B so as to provide optimal optical path lengths, even when the organic layer 112 that emits white light is used, light of different wavelengths that are intensified can be obtained from the light-emitting elements 110R, 110G, and 110B.

[0234] Furthermore, colored layers 116R, 116G, and 116B are provided on the optical paths of the light emitting elements 110R, 110G, and 110B, respectively, so that light with high color purity can be obtained.

[0235] An insulating layer 123 is provided to cover the edges of the pixel electrode 111, the conductive layer 115R, the conductive layer 115G, and the conductive layer 115B. The insulating layer 123 preferably has tapered edges. Providing the insulating layer 123 can improve coverage by the organic layer 112W, the common electrode 113, the protective layer 121, and the like formed thereon.

[0236] The organic layer 112W and the common electrode 113 are each provided as a continuous film common to each light-emitting element, which is preferable because it can greatly simplify the manufacturing process of the display panel.

[0237] Here, it is preferable that the edge of the pixel electrode 111 has a shape that is nearly vertical. This allows a steeply inclined portion to be formed on the surface of the insulating layer 123, and it is possible to form a thin portion in a part of the organic layer 112W that covers this portion, or to divide a part of the organic layer 112W. Therefore, it is possible to suppress leakage current that occurs through the organic layer 112W between adjacent light-emitting elements without processing the organic layer 112W using a photolithography method or the like.

[0238] 12C is a schematic cross-sectional view of a display panel 100c, which has a microlens on a light-emitting element.

[0239] The microlens 127 is provided above the light-emitting element 110 (in the direction in which the light is emitted). Because the light emitted by the display panel has a certain degree of divergence, light that does not enter the optical device is lost. Therefore, it is preferable for the display panel to have high front luminance. Because the microlens 127 has a convex lens shape, it acts in a direction that converges the light. In other words, it is possible to suppress the divergence of the light emitted by the light-emitting element, thereby improving the light utilization efficiency of the entire electronic device.

[0240] The microlenses 127 can be manufactured using the same material and process as the resin layer 126. Note that, although Fig. 12C shows an example in which the microlenses 127 are provided on the display panel 100, they can also be provided on the display panels 100a and 100b.

[0241] The above is a description of an example of the configuration of the display panel.

[0242] [Pixel Layout] The following mainly describes pixel layouts that are different from that shown in Fig. 11A. There are no particular limitations on the arrangement of light-emitting elements (sub-pixels), and various methods can be applied.

[0243] Examples of the top surface shape of the sub-pixel include a triangle, a quadrangle (including a rectangle and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, a circle, etc. Here, the top surface shape of the sub-pixel corresponds to the top surface shape of the light-emitting region of the light-emitting element.

[0244] An S-stripe arrangement is applied to the pixel 150 shown in Fig. 13A. The pixel 150 shown in Fig. 13A is composed of three sub-pixels, namely, light-emitting elements 110a, 110b, and 110c. For example, the light-emitting element 110a may be a blue light-emitting element, the light-emitting element 110b may be a red light-emitting element, and the light-emitting element 110c may be a green light-emitting element.

[0245] The pixel 150 shown in FIG. 13B includes a light-emitting element 110a having a generally trapezoidal or triangular top surface shape with rounded corners, a light-emitting element 110b having a generally trapezoidal or triangular top surface shape with rounded corners, and a light-emitting element 110c having a generally rectangular or hexagonal top surface shape with rounded corners. Furthermore, the light-emitting element 110a has a larger light-emitting area than the light-emitting element 110b. In this manner, the shape and size of each light-emitting element can be determined independently. For example, the more reliable the light-emitting element, the smaller the size can be. For example, the light-emitting element 110a may be a green light-emitting element, the light-emitting element 110b may be a red light-emitting element, and the light-emitting element 110c may be a blue light-emitting element.

[0246] The pixels 124a and 124b shown in Fig. 13C are arranged in a Pentile arrangement. Fig. 13C shows an example in which a pixel 124a having light-emitting elements 110a and 110b and a pixel 124b having light-emitting elements 110b and 110c are arranged alternately. For example, the light-emitting element 110a may be a red light-emitting element, the light-emitting element 110b may be a green light-emitting element, and the light-emitting element 110c may be a blue light-emitting element.

[0247] The pixels 124a and 124b shown in Figures 13D and 13E are arranged in a delta configuration. The pixel 124a has two light-emitting elements (light-emitting elements 110a and 110b) in the top row (first row) and one light-emitting element (light-emitting element 110c) in the bottom row (second row). The pixel 124b has one light-emitting element (light-emitting element 110c) in the top row (first row) and two light-emitting elements (light-emitting elements 110a and 110b) in the bottom row (second row). For example, the light-emitting element 110a may be a red light-emitting element, the light-emitting element 110b may be a green light-emitting element, and the light-emitting element 110c may be a blue light-emitting element.

[0248] FIG. 13D shows an example in which each light-emitting element has a substantially rectangular top surface shape with rounded corners, and FIG. 13E shows an example in which each light-emitting element has a circular top surface shape.

[0249] 13F shows an example in which light-emitting elements of each color are arranged in a zigzag pattern. Specifically, when viewed from above, the positions of the upper edges of two light-emitting elements arranged in a row (e.g., light-emitting elements 110a and 110b, or light-emitting elements 110b and 110c) are offset. For example, light-emitting element 110a may be a red light-emitting element, light-emitting element 110b may be a green light-emitting element, and light-emitting element 110c may be a blue light-emitting element.

[0250] In photolithography, the finer the pattern to be processed, the more significant the effect of light diffraction becomes. This reduces the fidelity of the photomask pattern when it is transferred by exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, it is likely to have rounded corners. As a result, the top surface shape of the light-emitting element may be polygonal with rounded corners, elliptical, circular, or the like.

[0251] Furthermore, in a method for manufacturing a display panel according to one embodiment of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the material for the EL layer and the curing temperature of the resist material, the resist film may not be cured sufficiently. A resist film that is not cured sufficiently may have a shape that deviates from the desired shape during processing. As a result, the top surface shape of the EL layer may become a polygon with rounded corners, an ellipse, a circle, or the like. For example, when a resist mask with a square top surface shape is formed, a resist mask with a circular top surface shape may be formed, resulting in a circular top surface shape of the EL layer.

[0252] In order to form the top surface of the EL layer into a desired shape, a technique for correcting a mask pattern in advance (OPC (Optical Proximity Correction) technique) may be used so that the design pattern and the transfer pattern coincide with each other. Specifically, the OPC technique adds a correction pattern to the corners of figures on the mask pattern.

[0253] This concludes the description of the pixel layout.

[0254] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0255] Embodiment 3 In this embodiment, another structural example of a display panel that can be applied to an electronic device of one embodiment of the present invention will be described.

[0256] The display panel of this embodiment is a high-definition display panel, and is particularly suitable for use as the display section of VR devices such as head-mounted displays, and wearable devices that can be worn on the head, such as eyeglass-type AR devices.

[0257] 14A shows a perspective view of a display module 280. The display module 280 has a display panel 200A and an FPC 290. Note that the display panel included in the display module 280 is not limited to the display panel 200A, and may be any of display panels 200B to 200F described below.

[0258] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display unit 281. The display unit 281 is an area for displaying an image.

[0259] 14B is a perspective view schematically illustrating the configuration on the substrate 291 side. A circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked on the substrate 291. A terminal portion 285 for connecting to the FPC 290 is provided in a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 composed of a plurality of wirings.

[0260] The pixel section 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of Fig. 14B. The pixel 284a has a light-emitting element 110R that emits red light, a light-emitting element 110G that emits green light, and a light-emitting element 110B that emits blue light.

[0261] The pixel circuit portion 283 has a plurality of pixel circuits 283a arranged periodically. Each pixel circuit 283a is a circuit that controls the light emission of three light-emitting devices included in one pixel 284a. One pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting device. For example, the pixel circuit 283a may be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitor for each light-emitting device. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to the source. This realizes an active matrix display panel.

[0262] The circuit portion 282 includes a circuit for driving each pixel circuit 283a in the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like. Furthermore, a transistor provided in the circuit portion 282 may constitute a part of the pixel circuit 283a. That is, the pixel circuit 283a may be composed of a transistor included in the pixel circuit portion 283 and a transistor included in the circuit portion 282.

[0263] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, etc. from the outside to the circuit portion 282. An IC may be mounted on the FPC 290.

[0264] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are provided overlapping below the pixel unit 284, thereby enabling the aperture ratio (effective display area ratio) of the display unit 281 to be extremely high. For example, the aperture ratio of the display unit 281 can be set to 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. Furthermore, the pixels 284a can be arranged at an extremely high density, enabling the pixel density of the display unit 281 to be extremely high. For example, it is preferable that the pixels 284a be arranged in the display unit 281 at a pixel density of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20,000 ppi or less, or 30,000 ppi or less.

[0265] Because such a display module 280 has extremely high resolution, it can be suitably used in VR devices such as head-mounted displays, or eyeglass-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display unit 281, so even if the display unit is enlarged with the lenses, the pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 280 is not limited to this, and can be suitably used in electronic devices with relatively small display units. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0266] [Display Panel 200A] The display panel 200A shown in FIG. 15 includes a substrate 301, light-emitting elements 110R, 110G, and 110B, a capacitor 240, and a transistor 310.

[0267] Substrate 301 corresponds to substrate 291 in FIGS. 14A and 14B.

[0268] The transistor 310 has a channel formation region in a substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities and functions as one of a source and a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0269] An element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0270] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0271] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located therebetween. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as a dielectric of the capacitor 240.

[0272] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain of the transistor 310 by a plug 271 buried in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0273] An insulating layer 255a is provided to cover the capacitor 240, an insulating layer 255b is provided over the insulating layer 255a, and an insulating layer 255c is provided over the insulating layer 255b.

[0274] An inorganic insulating film can be preferably used for each of the insulating layers 255a, 255b, and 255c. For example, it is preferable to use a silicon oxide film for the insulating layer 255a and the insulating layer 255c, and a silicon nitride film for the insulating layer 255b. This allows the insulating layer 255b to function as an etching protection film. In this embodiment, an example is shown in which part of the insulating layer 255c is etched to form a recess, but the insulating layer 255c does not necessarily have to have a recess.

[0275] The light emitting elements 110R, 110G, and 110B are provided over the insulating layer 255c. Embodiment 2 can be referred to for the structures of the light emitting elements 110R, 110G, and 110B.

[0276] The display panel 200A has a separate light-emitting device for each emitted color, so there is little change in chromaticity between low-luminance and high-luminance emission. Furthermore, because the organic layers 112R, 112G, and 112B are spaced apart from one another, crosstalk between adjacent subpixels can be suppressed even in a high-resolution display panel. This makes it possible to realize a high-resolution display panel with high display quality.

[0277] In the region between adjacent light emitting elements, an insulating layer 125, a resin layer 126, and a layer 128 are provided.

[0278] The pixel electrodes 111R, 111G, and 111B of the light-emitting element are electrically connected to one of the source and drain of the transistor 310 via a plug 256 embedded in the insulating layers 255a, 255b, and 255c, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. The height of the top surface of the insulating layer 255c and the height of the top surface of the plug 256 are the same or approximately the same. Various conductive materials can be used for the plug.

[0279] A protective layer 121 is provided on the light emitting elements 110R, 110G, and 110B. A substrate 170 is attached to the protective layer 121 with an adhesive layer 171.

[0280] There is no insulating layer covering the upper end of each pixel electrode 111 between two adjacent pixel electrodes 111. This allows the distance between adjacent light-emitting elements to be extremely narrow, resulting in a high-definition or high-resolution display panel.

[0281] 16 has a stacked structure of a transistor 310A and a transistor 310B, each of which has a channel formed in a semiconductor substrate. Note that in the following description of the display panel, descriptions of parts that are the same as those of the display panel described above may be omitted.

[0282] The display panel 200B has a structure in which a substrate 301B provided with a transistor 310B, a capacitor 240, and a light-emitting device and a substrate 301A provided with a transistor 310A are bonded together.

[0283] Here, an insulating layer 345 is provided on the lower surface of the substrate 301B, and an insulating layer 346 is provided on the insulating layer 261 provided on the substrate 301A. The insulating layers 345 and 346 function as protective layers and can suppress the diffusion of impurities into the substrates 301B and 301A. The insulating layers 345 and 346 can be made of an inorganic insulating film that can be used for the protective layer 121.

[0284] The substrate 301B is provided with a plug 343 that penetrates the substrate 301B and an insulating layer 345. Here, it is preferable to provide an insulating layer 344 that covers the side surface of the plug 343 and functions as a protective layer.

[0285] Furthermore, in the substrate 301B, a conductive layer 342 is provided below the insulating layer 345. The conductive layer 342 is embedded in the insulating layer 335, and the lower surfaces of the conductive layer 342 and the insulating layer 335 are flattened. The conductive layer 342 is electrically connected to a plug 343.

[0286] On the other hand, in the substrate 301A, a conductive layer 341 is provided on an insulating layer 346. The conductive layer 341 is embedded in the insulating layer 336, and the upper surfaces of the conductive layer 341 and the insulating layer 336 are flattened.

[0287] It is preferable to use the same conductive material for the conductive layers 341 and 342. For example, a metal film containing an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, or a nitride film containing the above elements (titanium nitride film, molybdenum nitride film, tungsten nitride film), etc., can be used. In particular, it is preferable to use copper for the conductive layers 341 and 342. This allows for the application of Cu-Cu (copper-copper) direct bonding technology (technology that achieves electrical conductivity by connecting Cu (copper) pads together).

[0288] [Display Panel 200C] A display panel 200C shown in FIG. 17 has a configuration in which a conductive layer 341 and a conductive layer 342 are joined via a bump 347.

[0289] 17 , by providing a bump 347 between the conductive layer 341 and the conductive layer 342, the conductive layer 341 and the conductive layer 342 can be electrically connected. The bump 347 can be formed using a conductive material containing, for example, gold (Au), nickel (Ni), indium (In), tin (Sn), or the like. Alternatively, for example, solder may be used as the bump 347. An adhesive layer 348 may be provided between the insulating layer 345 and the insulating layer 346. When the bump 347 is provided, the insulating layer 335 and the insulating layer 336 may not be provided.

[0290] [Display Panel 200D] The display panel 200D shown in FIG. 18 differs from the display panel 200A mainly in the configuration of the transistors.

[0291] The transistor 320 is a transistor (OS transistor) in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

[0292] The transistor 320 includes a semiconductor layer 321 , an insulating layer 323 , a conductive layer 324 , a pair of conductive layers 325 , an insulating layer 326 , and a conductive layer 327 .

[0293] Substrate 331 corresponds to substrate 291 in FIGS. 14A and 14B.

[0294] An insulating layer 332 is provided over a substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320 and prevents oxygen from being released from the semiconductor layer 321 toward the insulating layer 332. The insulating layer 332 can be, for example, a film through which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0295] A conductive layer 327 is provided over the insulating layer 332, and an insulating layer 326 is provided to cover the conductive layer 327. The conductive layer 327 functions as a first gate electrode of the transistor 320, and part of the insulating layer 326 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a portion of the insulating layer 326 that is in contact with the semiconductor layer 321. The top surface of the insulating layer 326 is preferably planarized.

[0296] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide (also referred to as an oxide semiconductor) film exhibiting semiconductor characteristics. A pair of conductive layers 325 is provided on and in contact with the semiconductor layer 321 and functions as a source electrode and a drain electrode.

[0297] An insulating layer 328 is provided to cover top surfaces and side surfaces of the pair of conductive layers 325 and side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided over the insulating layer 328. The insulating layer 328 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 264 or the like into the semiconductor layer 321 and prevents oxygen from being released from the semiconductor layer 321. The insulating layer 328 can be an insulating film similar to the insulating layer 332.

[0298] An opening reaching the semiconductor layer 321 is provided in the insulating layer 328 and the insulating layer 264. An insulating layer 323 in contact with the top surface of the semiconductor layer 321 and a conductive layer 324 are buried in the opening. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0299] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are the same or approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0300] The insulating layer 264 and the insulating layer 265 function as interlayer insulating layers. The insulating layer 329 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 265 or the like to the transistor 320. The insulating layer 329 can be formed using an insulating film similar to the insulating layer 328 and the insulating layer 332.

[0301] A plug 274 electrically connected to one of the pair of conductive layers 325 is provided so as to be embedded in the insulating layer 265, the insulating layer 329, and the insulating layer 264. Here, the plug 274 preferably has a conductive layer 274a covering the side surfaces of the openings of the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328 and a part of the upper surface of the conductive layer 325, and a conductive layer 274b in contact with the upper surface of the conductive layer 274a. In this case, it is preferable to use a conductive material through which hydrogen and oxygen do not easily diffuse as the conductive layer 274a.

[0302] Note that the structure of the transistor included in the display panel of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Furthermore, either a top-gate transistor or a bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0303] The transistor 320 has a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates may be connected and the transistor may be driven by supplying the same signal to them. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential for controlling the threshold voltage to one of the two gates and a potential for driving to the other.

[0304] The crystallinity of a semiconductor material used for a semiconductor layer of a transistor is not particularly limited, and any of an amorphous semiconductor, a single-crystal semiconductor, and a semiconductor having crystallinity other than single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single-crystal semiconductor or a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0305] The band gap of the metal oxide used for the semiconductor layer of the transistor is preferably 2 eV or more, more preferably 2.5 eV or more. Use of a metal oxide with a wide band gap can reduce the off-state current of the OS transistor.

[0306] The metal oxide preferably contains at least indium or zinc, and more preferably contains indium and zinc. For example, the metal oxide preferably contains indium, M (M is one or more selected from gallium, aluminum, yttrium, tin, silicon, boron, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt), and zinc.

[0307] Alternatively, the semiconductor layer of the transistor may contain silicon, such as amorphous silicon or crystalline silicon (such as low-temperature polysilicon or single-crystal silicon).

[0308] Examples of metal oxides that can be used in the semiconductor layer include indium oxide, gallium oxide, and zinc oxide. The metal oxide preferably contains two or three elements selected from indium, element M, and zinc. The element M is one or more elements selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium. In particular, the element M is preferably one or more elements selected from aluminum, gallium, yttrium, and tin.

[0309] When a metal oxide is used for the semiconductor layer, the metal oxide is preferably formed by a sputtering method or an ALD method. When the metal oxide is formed by a sputtering method, productivity and film density can be increased. When the metal oxide is formed by an ALD method, film coverage can be increased.

[0310] In particular, as the metal oxide used in the semiconductor layer, it is preferable to use an oxide containing indium, gallium, and zinc (also referred to as IGZO). Alternatively, it is preferable to use an oxide containing indium, tin, and zinc (also referred to as ITZO (registered trademark)). Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, aluminum, and zinc (also referred to as IAZO). Alternatively, it is preferable to use an oxide containing indium, aluminum, gallium, and zinc (also referred to as IAGZO).

[0311] When the metal oxide used in the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. Examples of atomic ratios of metal elements in such an In-M-Zn oxide include a composition of In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:1:1 or thereabouts, In:M:Zn=1:1:1.2 or thereabouts, In:M:Zn=1:3:2 or thereabouts, In:M:Zn=1:3:4 or thereabouts, In:M:Zn=2:1:3 or thereabouts, In:M:Zn=3:1:2 or thereabouts, In:M:Zn=4:2: Examples of such compositions include a composition of In:M:Zn=4:2:4.1 or a composition of In:M:Zn=5:1:3 or a composition of In:M:Zn=5:1:6 or a composition of In:M:Zn=5:1:7 or a composition of In:M:Zn=5:1:8 or a composition of In:M:Zn=6:1:6 or a composition of In:M:Zn=5:2:5 or a composition of In:M:Zn=5:2:5. Note that a composition of a similar ratio includes a range of ±30% of the desired atomic ratio.

[0312] Furthermore, it is preferable to use gallium or tin as the element M. Note that the element M may be a combination of two or more of the above elements. It is also preferable to use In:M:Zn=40:1:10 or a metal oxide thereof in the semiconductor layer. Specifically, it is preferable to use In:Sn:Zn=40:1:10 or a metal oxide thereof in the semiconductor layer.

[0313] For example, when describing a composition having an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, this includes a case where, when In is taken as 4, Ga is 1 to 3 and Zn is 2 to 4. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, this includes a case where, when In is taken as 5, Ga is more than 0.1 and 2 or less and Zn is 5 to 7. Furthermore, when describing a composition having an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, this includes a case where, when In is taken as 1, Ga is more than 0.1 and 2 or less and Zn is more than 0.1 and 2 or less.

[0314] The semiconductor layer may also have two or more metal oxide layers with different compositions. For example, a stacked structure of a first metal oxide layer having an In:M:Zn=1:3:4 (atomic ratio) or a composition similar thereto and a second metal oxide layer having an In:M:Zn=1:1:1 (atomic ratio) or a composition similar thereto provided on the first metal oxide layer is preferably used. Gallium or aluminum is particularly preferably used as the element M.

[0315] Alternatively, for example, a stacked structure of any one selected from indium oxide, indium gallium oxide, and IGZO and any one selected from IAZO, IAGZO, and ITZO (registered trademark) may be used.

[0316] Examples of crystalline oxide semiconductors include c-axis-aligned crystalline (CAAC)-OS, nanocrystalline (nc)-OS, and the like.

[0317] An OS transistor has significantly higher field-effect mobility than a transistor using amorphous silicon. Furthermore, an OS transistor has significantly lower source-drain leakage current (also referred to as off-state current) in an off state, and can hold charge accumulated in a capacitor connected in series with the transistor for a long period of time. Furthermore, the use of an OS transistor can reduce the power consumption of a display panel.

[0318] Furthermore, to increase the emission luminance of a light-emitting device included in a pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting device. To achieve this, it is necessary to increase the source-drain voltage of a driving transistor included in the pixel circuit. Since an OS transistor has a higher source-drain withstand voltage than a Si transistor, a high voltage can be applied between the source and drain of the OS transistor. Therefore, by using an OS transistor as the driving transistor included in a pixel circuit, it is possible to increase the amount of current flowing through the light-emitting device and increase the emission luminance of the light-emitting device.

[0319] Furthermore, when the transistor operates in the saturation region, the change in source-drain current of an OS transistor is smaller than that of a Si transistor in response to a change in gate-source voltage. Therefore, by using an OS transistor as a driving transistor included in a pixel circuit, the current flowing between the source and drain can be precisely controlled by changing the gate-source voltage, thereby controlling the amount of current flowing through the light-emitting device. This allows for a larger number of gray levels to be displayed in the pixel circuit.

[0320] Furthermore, in terms of the saturation characteristics of the current that flows when a transistor operates in the saturation region, an OS transistor can pass a more stable current (saturation current) than a Si transistor, even when the source-drain voltage gradually increases. Therefore, by using an OS transistor as a driving transistor, a stable current can be passed through a light-emitting device, even when the current-voltage characteristics of an EL device vary. In other words, when an OS transistor operates in the saturation region, the source-drain current of the OS transistor remains almost unchanged even when the source-drain voltage increases, thereby stabilizing the light-emitting luminance of the light-emitting device.

[0321] As described above, by using an OS transistor for a driving transistor included in a pixel circuit, it is possible to achieve "reduced power consumption," "increased light emission luminance," "multiple gray levels," "suppressed variations in light-emitting devices," and the like.

[0322] [Display Panel 200F] A display panel 200F shown in FIG. 19 has a stacked structure of a transistor 310 in which a channel is formed in a substrate 301 and a transistor 320 in which a channel is formed and a semiconductor layer containing metal oxide is formed.

[0323] An insulating layer 261 is provided to cover the transistor 310, and a conductive layer 251 is provided over the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided over the insulating layer 262. The conductive layers 251 and 252 each function as wirings. An insulating layer 263 and an insulating layer 332 are provided to cover the conductive layer 252, and the transistor 320 is provided over the insulating layer 332. An insulating layer 265 is provided to cover the transistor 320, and a capacitor 240 is provided over the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0324] The transistor 320 can be used as a transistor that forms a pixel circuit. The transistor 310 can be used as a transistor that forms a pixel circuit or a driver circuit (gate line driver circuit, source line driver circuit) that drives the pixel circuit. The transistors 310 and 320 can be used as transistors that form various circuits such as an arithmetic circuit or a memory circuit.

[0325] With this configuration, not only pixel circuits but also driving circuits etc. can be formed directly below the light-emitting device, which makes it possible to make the display panel smaller than when driving circuits are provided around the periphery of the display area.

[0326] [Display Panel 200G] The display panel 200G shown in Fig. 20 has a configuration in which the transistor 320 of the display panel 200F shown in Fig. 19 is replaced with a transistor 320A (vertical transistor). Note that the configuration in which the transistor 320 is replaced with the transistor 320A can also be applied to the display panel 200D shown in Fig. 18.

[0327] 21A shows a cross-sectional view of the transistor 320A in the XZ plane, and FIG. 21B shows a cross-sectional view of the transistor 320A in the XY plane including the wiring 440.

[0328] The transistor 320A includes 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 one of a source electrode and a drain electrode of the transistor 320A. The wiring 440 has a region that functions as the other of the source electrode and the drain electrode of the transistor 320A.

[0329] An opening 490 is provided through the wiring 440 and the insulator 480, reaching the wiring 450. The opening 490 has a columnar shape with a substantially circular upper surface. This structure allows for miniaturization or high integration of memory cells. Note that the side surface of the opening 490 is preferably perpendicular to the upper surface of the wiring 450.

[0330] At least a part of the oxide semiconductor 470 is disposed in the opening 490. Note that the oxide semiconductor 470 has a region in contact with the top 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.

[0331] The insulator 430 is disposed so that at least a portion thereof covers the opening 490. The conductor 420 is disposed so that at least a portion thereof is located in the opening 490. Note that the conductor 420 is preferably provided so as to fill the opening 490, and the top surface thereof is preferably approximately circular in order to increase the degree of integration.

[0332] As illustrated in FIG. 21A, the oxide semiconductor 470 includes a region 470i and regions 470na and 470nb that sandwich the region 470i.

[0333] The region 470na is a region of the oxide semiconductor 470 that is in contact with the wiring 450. At least a part of the region 470na functions as one of the source region and the drain region of the transistor 320A. The region 470nb is a region of the oxide semiconductor 470 that is in contact with the wiring 440. At least a part of the region 470nb functions as the other of the source region and the drain region of the transistor 320A. As shown in FIG. 21B , the wiring 440 is in contact with the entire periphery of the oxide semiconductor 470. Therefore, the other of the source region and the drain region of the transistor 320A can be formed along the entire periphery of a portion of the oxide semiconductor 470 that is formed in the same layer as the wiring 440.

[0334] The region 470i is a region sandwiched between the regions 470na and 470nb in the oxide semiconductor 470. At least part of the region 470i functions as a channel formation region of the transistor 320A. That is, the channel formation region of the transistor 320A is formed in a part of the oxide semiconductor 470 located between the wiring 450 and the wiring 440. It can also be said that the channel formation region of the transistor 320A is located in a region of the oxide semiconductor 470 that is in contact with the insulator 480 or in a region in the vicinity of the insulator 480.

[0335] The channel length of the transistor 320A is the distance between the source region and the drain region. In other words, the channel length of the transistor 320A can be determined by the thickness of the insulator 480 on the wiring 450. In FIG. 21A , the channel length L of the transistor 320A is indicated by a dashed double-headed arrow. The channel length L is the distance between the end of the region where the oxide semiconductor 470 and the wiring 450 contact each other and the end of the region where the oxide semiconductor 470 and the wiring 440 contact each other in a cross-sectional view. 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.

[0336] In a planar transistor, the channel length is limited by the exposure limit of photolithography, making further miniaturization difficult. However, in one embodiment of the present invention, the channel length can be set by the film thickness of the insulator 480. Therefore, the channel length of the transistor 320A can be made into an extremely fine structure that is equal to or less than 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 allows the on-state current of the transistor 320A to be increased.

[0337] Furthermore, as described above, the channel formation region, the source region, and the drain region can be formed in the opening 490. This allows the area occupied by the transistor 320A to be reduced compared to a conventional transistor in which the channel formation region, the source region, and the drain region are provided separately on the XY plane, thereby increasing the pixel density.

[0338] A transistor having a channel formation region along the side surface of the insulator 480 in the opening 490 is also called a vertical transistor.

[0339] 21B , the oxide semiconductor 470, the insulator 430, and the conductor 420 are arranged concentrically in the XY plane including the channel formation region of the oxide semiconductor 470. Therefore, the side surface of the conductor 420 located at the center faces the side surface of the oxide semiconductor 470 with the insulator 430 interposed therebetween. That is, the entire periphery of the oxide semiconductor 470 forms the channel formation region in a top view. In this case, for example, the channel width of the transistor 320A is determined by the perimeter of the oxide semiconductor 470. That is, the channel width of the transistor 320A can be determined by the maximum width of the opening 490 (the maximum diameter when the opening 490 is circular in a top view). In FIGS. 21A and 21B , the maximum width D of the opening 490 is indicated by a double-headed, dashed arrow. In FIG. 21B , the channel width W of the transistor 320A is indicated by a double-headed, dashed 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.

[0340] When the opening 490 is formed by photolithography, the maximum width D of the opening 490 is limited by the exposure limit of photolithography. The maximum width D of the opening 490 is set depending on the film thicknesses of the oxide semiconductor 470, the insulator 430, and the conductor 420 provided in the opening 490. The maximum width D of the opening 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. When the opening 490 has a circular shape in top view, the maximum width D of the opening 490 corresponds to the diameter of the opening 490, and the channel width W can be calculated as "D × π".

[0341] In the memory device of one embodiment of the present invention, the channel length L of the transistor 320A is preferably at least shorter than the channel width W of the transistor 320A. The channel length L of the transistor 320A of one embodiment of the present invention is 0.1 to 0.99 times, preferably 0.5 to 0.8 times, the channel width W of the transistor 320A. With such a structure, a transistor with favorable electrical characteristics and high reliability can be realized.

[0342] Furthermore, by forming the opening 490 to have a substantially circular shape in top view, the oxide semiconductor 470, the insulator 430, and the conductor 420 are arranged concentrically. This makes the distance between the conductor 420 and the oxide semiconductor 470 substantially uniform, allowing a gate electric field to be applied to the oxide semiconductor 470 substantially uniformly.

[0343] The channel formation region of a transistor using an oxide semiconductor for a semiconductor layer preferably has fewer oxygen vacancies or a lower concentration of impurities such as hydrogen, nitrogen, or metal elements than the source and drain regions. For example, the aluminum concentration in the channel formation region of the oxide semiconductor is preferably 1×10 ２２ atoms / cm ３ Preferably, 1×10 ２１ atoms / cm ３ More preferably, 1×10 ２０ atoms / cm ３ Less than 5 x 10 is more preferable. １９ atoms / cm ３ More preferably, 1×10 or less １９ atoms / cm ３ Less than 5 x 10 is more preferable. １８ atoms / cm ３ More preferably, 1×10 or less １８ atoms / cm ３ The following is even more preferred:

[0344] In addition, hydrogen atoms near the oxygen vacancies are converted into defects where hydrogen atoms have entered the oxygen vacancies (hereinafter referred to as V Ｏ H) and generate electrons that become carriers. Therefore, in the channel formation region, V Ｏ It is preferable that H is also reduced. In this way, the channel formation region of the transistor is a high-resistance region with a low carrier concentration. Therefore, the channel formation region of the transistor can be said to be i-type (intrinsic) or substantially i-type.

[0345] In addition, the source and drain regions of a transistor using an oxide semiconductor for a semiconductor layer have more oxygen vacancies than the channel formation region. ＯThe source and drain regions of a transistor are n-type regions with a high carrier concentration and low resistance compared to the channel formation region, due to a high concentration of H or a high concentration of impurities such as hydrogen, nitrogen, and metal elements.

[0346] 21A and other drawings, the opening 490 is provided so that the side surface of the opening 490 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.

[0347] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes and examples described in this specification.

[0348] La: support, Lb: support, 10: eye, 20: display panel, 21: display unit, 30: optical device, 31: half mirror, 31a: reflective surface, 31b: reflective surface, 32: lens, 33: retardation plate, 34: reflective polarizer, 34a: reflective surface, 35: lens, 40: catadioptric system, 46: optical axis, 54: lens, 55a: adhesive layer, 55b: adhesive layer, 55d: adhesive layer, 55g: adhesive layer, 56: convex lens, 57 Concave lens, 62: reflective polarizer, 62a: reflective surface, 63: retardation plate, 70: pixel, 71: subpixel, 74: pixel array, 75: circuit, 76: circuit, 77: layer, 78: layer, 79: layer, 90: housing, 91: band, 92: display unit, 100: display panel, 100a: display panel, 100b: display panel, 100c: display panel, 101: substrate, 110: light-emitting element, 110a: light-emitting element, 110B: light-emitting element, 110b: light-emitting element, 110c: light-emitting element, 110G: Light-emitting element, 110R: light-emitting element, 110W: light-emitting element, 111: pixel electrode, 111B: pixel electrode, 111C: connection electrode, 111G: pixel electrode, 111R: pixel electrode, 112: organic layer, 112B: organic layer, 112G: organic layer, 112R: organic layer, 112W: organic layer, 113: common electrode, 114: common layer, 115B: conductive layer, 115G: conductive layer, 115R: conductive layer, 116B: colored layer, 116G: colored layer, 116R: colored layer, 121: protective layer, 122: insulating layer, 1 23: insulating layer, 124a: pixel, 124b: pixel, 125: insulating layer, 126: resin layer, 127: microlens, 128: layer, 140: connecting portion, 150: pixel, 170: substrate, 171: adhesive layer, 200A: display panel, 200B: display panel, 200C: display panel, 200D: display panel, 200F: display panel, 200G: display panel, 240: capacitor, 241: conductive layer, 243: insulating layer, 245: conductive layer, 251: conductive layer, 252: conductive layer, 254: insulation 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, 280: display module, 281: display section, 282: circuit section, 283: pixel circuit section, 283a: pixel circuit, 284: pixel section, 284a: pixel, 285: terminal section, 286: wiring section, 290: FPC, 291: substrate,292: substrate, 301: substrate, 301A: substrate, 301B: substrate, 310: transistor, 310A: transistor, 310B: transistor, 311: conductive layer, 312: low resistance region, 313: 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: insulation 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 optical device applied to an electronic device using a non-polarized light source, A first lens and a catadioptric system, the first lens is provided between the unpolarized light source and the catadioptric system; the first lens is an aspheric singlet lens; the catadioptric optical system includes a second lens, a third lens, and a unit having a half mirror between a first support and a second support, The unit is provided between the second lens and the third lens, the first lens is made of resin, The optical instrument, wherein the first support, the second support, the second lens, and the third lens are made of glass. 　 In claim 1, The first lens has a region that acts as a convex lens and a region that acts as a concave lens, and the shapes of the front and back surfaces are asymmetric. 　 In claim 1, The catadioptric system has a plurality of optical elements arranged in plane symmetry with respect to the half mirror, and the pair of plane symmetric optical elements have the same optical characteristics. 　 In claim 3, the catadioptric system includes a first reflective polarizer, a second reflective polarizer, a first retardation plate, and a second retardation plate; the second lens and the first retardation plate are provided between the first reflective polarizing plate and the first support, The optical device, wherein the third lens and the second retardation plate are provided between the second reflective polarizer and the second support. 　 In claim 4, The catadioptric system is an optical device in which the first reflective polarizing plate, the second lens, the first retardation plate, the first support, the half mirror, the second support, the second retardation plate, the third lens, and the second reflective polarizing plate are arranged in this order. 　 In claim 1, The optical device, wherein the first support and the second support are flat. 　 In claim 1, The optical apparatus, wherein the second lens and the third lens are plano-convex lenses. 　 In claim 7, The optical device, wherein the second lens and the third lens are each a spherical lens. 　 In claim 7, The optical device, wherein the second lens and the third lens are each an aspheric lens.

10. An electronic device comprising: the optical device according to claim 1; and an organic EL panel as the non-polarized light source, the organic EL panel having a microlens provided on an organic EL element.

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