Abstract: An image display device for causing an optical image to be visible including: a display to emit image light; and a light guide to guide the image light from the display to an outside. The light guide has principal surfaces, including: an incident region to diffract the image to propagate inside the light guide by reflection between principal surfaces, in response to incidence of the image light from the display; and an expansion region to diffract the propagated image light to emit the diffracted image light as beams of image light from positions. The image light propagated to the expansion region has a first polarization state polarized along a direction parallel or perpendicular to a plane including a normal direction in the expansion region and a propagation direction by setting the image light incident on the incident region to have a second polarization state different from the first polarization state.

Abstract: The optical system includes a light guide including: an incident region allowing an image light ray to enter a body; and an exit extension region including a diffraction structure dividing an image light ray into image light rays and allowing them to emerge from the body. The exit extension region divides the image light ray into first to third image light rays. The first and third image light rays emerge from the exit extension region at different angles to propagate inside the body. The exit extension region includes an overlap part on which the first image light ray and the third image light ray are incident under a condition where they partially overlap with each other. A difference between optical paths of the first image light ray and the third image light ray incident on the overlap part is longer than a coherence length of the image light ray.

Abstract: A light guide includes an exit extension region including a diffraction structure dividing an image light ray propagating in a first direction intersecting a thickness direction of a body, into image light rays propagating in a second direction intersecting the first direction, in the first direction, and allowing them to emerge therefrom. At least one part of the region satisfies that when refractive indices of media on individual incident and exit sides of a ray relative to the region are assumed to be equal to each other, an exit angle ?_out of a ray emerging from the region at the highest diffraction efficiency in a plane including a normal line of the region is not smaller than 15° and is not greater than 45°, and an incident angle ?_in of a ray incident on the region in the plane is greater than ?_out by 14° or more.

Abstract: Imaging and display system includes: a display; an optical system including a first mirror and a second mirror; a housing; a light-transmissive cover transparent to light and disposed to cover at least part of an opening of the housing; and a driver monitoring camera supported by a supporting body connected outside of the housing. First light emitted from the display passes through the light-transmissive cover via the optical system, and is reflected by a windshield toward a direction of the user. The driver monitoring camera captures an image of a driver shown on the light-transmissive cover by second light from a direction of the driver reflected by the windshield toward a direction of the light-transmissive cover.

Abstract: An optical system includes an incidence part changing a traveling direction of the incident image light from a display part and an expansion part that divides and duplicates the image light traveling from the incidence part. The expansion part includes a first and a second expansion part. The first expansion part includes a first and a second diffraction structure part each having a diffraction structure that divides and duplicates the image light along a first direction, and a non-diffraction structure part disposed between the first and the second diffraction structure part. The second expansion part includes a third diffraction structure part that divides and duplicates image light along the first direction. The third diffraction structure part is disposed to overlap with the non-diffraction structure part of the first expansion part in a vertical direction with respect to the pupil expansion part.

Abstract: The optical system includes a light guide including a reproduction region including a dividing diffraction structure dividing an image light ray propagating in a first propagation direction intersecting a thickness direction of a body, into image light rays propagating in a second propagation direction intersecting the first propagation direction, in the first propagation direction and including first and second diffraction structure regions formed respectively at first and second surfaces in the thickness direction to face each other, and an exit diffraction structure allowing the image light rays propagating in the second propagation direction to travel toward a field of view region. When first and second field of view angles in first and second directions of the virtual image are denoted by FOV1 and FOV2, a relation of FOV2/FOV1<0.5 is satisfied. The first propagation direction in the reproduction region corresponds to the first direction in a virtual image.

Abstract: The optical system includes: a light guide for guiding an image light ray to a field of view region of a user as a virtual image. The light guide includes a diffraction structure region constituting a surface-relief diffraction grating dividing the image light ray propagating in a first propagation direction intersecting a thickness direction of a body into a plurality of image light rays propagating in a second propagation direction intersecting the first propagation direction, in the first propagation direction. The diffraction structure region includes a first diffraction structure, and a second diffraction structure on an opposite side of the first diffraction structure from an in-coupling region in the first propagation direction. A grating height of the first diffraction structure is greater than a grating height of the second diffraction structure. A grating width of the first diffraction structure is greater than a grating width of the second diffraction structure.

Abstract: A display device displays a virtual image by projecting an image onto a windshield provided on a vehicle and having a curved shape. The display device includes: an image generation device that generates light (image light) representing an image; and a light guide that includes an emission hologram element having a non-rectangular quadrilateral shape. The emission hologram element emits, toward the windshield, the light representing the image and propagating through the light guide.

Abstract: An optical lens is used for light in a predetermined target wavelength region. The optical lens includes a substrate and a plurality of microstructures arranged on a surface of the substrate at intervals shorter than the shortest wavelength in the target wavelength region. The structure and/or the interval of each of the plurality of microstructures is determined in such a way as to compensate for a variation in phase and/or transmittance depending on the incident angle of the incident light at each position in the region where the plurality of microstructures is provided.

Abstract: There is provided a vent assembly comprising a first connecting layer, a spacer, and a protective element, the first connecting layer comprises a first aperture, wherein the spacer comprises a spacer aperture and the protective element is located within the spacer aperture and occludes the first aperture, and wherein the spacer and protective element are contacted by the first connecting layer.

Abstract: A head-up display system displays a virtual image superimposed on a real view that can be visually recognized through a window part. The head-up display system includes a display part, an optical system, a light source part, an operation part, and a controller. The controller controls a display area of the display part in accordance with an operation of the operation part by the observer. The light flux emitted from the display part is reflected by the window part and reaches a visually recognizable area where the observer can visually recognize the virtual image. The light emitted from the light source part is reflected inside an area where the light flux is reflected by the window part and reaches the visually recognizable area. The virtual image and the light from the light source part are superimposed, and can be visually recognized.

Abstract: The optical system includes a light guide guiding an image light ray including a first light ray with a first wavelength range and a second light ray with a second wavelength range having wavelengths shorter than wavelengths in the first wavelength range, to a field of view region as a virtual image. The light guide includes a first dividing region including first dividing points dividing the incident first light ray and a second dividing region including second dividing points dividing the incident second light ray. The first dividing points include first and second points respectively corresponding to first and second peripheral regions of the field of view region. The second dividing points include third and fourth points respectively corresponding to the first and second peripheral regions. Dividing efficiencies E1 to E4 at the first to fourth points satisfy the following formula (1). ( E ? 2 E ? 1 ) ÷ ( E ? 4 E ? 3 ) × ( E ? 3 E ? 1 ) 2 < 0.

Abstract: An optical system includes a display that emits a light flux visually recognized by an observer as an image, and a light guide body that replicates the light flux. The light flux is emitted from the emission surface after being expanded by being replicated in a first direction corresponding to a horizontal direction of the image visually recognized by the observer due to diffraction by a diffraction structure of an expansion region in the light guide body, a second direction corresponding to a vertical direction of the image, or both the directions. A coherence length of the light flux diffracted and emitted in the expansion region in the light guide body is smaller than twice a shorter interval between the diffraction structure and each of a front surface and a back surface of the light guide body.

Abstract: A light flux incident on the light guide body is replicated in a first direction or a second direction by a diffraction structure of an expansion region. When a normal direction with respect to the light guide body of the expansion region is defined as a Z-axis direction, and a tangential plane is defined as an XY plane, the diffraction structure of the expansion region is configured such that a light flux duplicated when the light flux incident on the expansion region is transmitted through the XY plane of the expansion region from a positive direction of the Z axis and a light flux duplicated when the light flux is transmitted through the XY plane of the expansion region from a negative direction of the Z axis are accommodated within a viewing angle at which the image is visually recognizable.

Abstract: An optical system includes a light guide for guiding an image light ray output from a display element to a field of view region as a virtual image. The light guide includes a periodic structure formed in the body having a plate shape. The periodic structure has periodicity in three predetermined directions intersecting each other within a predetermined plane perpendicular to a thickness direction of the body. The periodic structure includes an in-coupling region dividing the image light ray into a plurality of image light rays and allowing the plurality of image light rays to propagate within the body in a plurality of branch directions including branch directions respectively parallel to the predetermined directions, and an exit region allowing the plurality of image light rays propagating in the plurality of branch directions within the body to emerge from the body toward the field of view region.

Abstract: An image display device includes a display, a light guide body, a controller, and a sensor. The light guide body includes an incident surface on which the light flux from the display is incident and an emission surface from which the light flux is emitted from the light guide body. The light flux incident on the incident surface of the light guide body is changed in a traveling direction in the light guide body, and is emitted from the emission surface so as to expand a visual field area by being replicated in a horizontal direction and a vertical direction of the virtual image visually recognized by the observer. The sensor that detects a physical quantity used to obtain a wavelength of the light flux. The controller controls a position and a shape of the image displayed by the display based on the physical quantity detected by the sensor.

Abstract: An optical system includes a light guide for guiding an image light ray which is output from a display element and forms an image, to a field of view region of a user as a virtual image. The light guide includes a body having a plate shape, and an in-coupling region and an exit region which are formed in the body. The in-coupling region allows the image light ray incident from the display element to propagate within the body. The exit region allows the image light ray propagating within the body to emerge from the body toward the field of view region. The in-coupling region includes a periodic structure constituted by recessed or protruded parts in relation to a thickness direction of the body which are arranged to have periodicity in three predetermined directions intersecting each other within a predetermined plane perpendicular to the thickness direction of the body.

Abstract: A light guide plate includes a first hologram element including a plurality of diffraction cells. At least one of edge lines of one diffraction cell among the plurality of diffraction cells included in the first hologram element is located at a position other than on extensions of all edge lines of an adjacent diffraction cell adjacent to the one diffraction cell, the adjacent diffraction cell being included in the plurality of diffraction cells.

Abstract: A light guide plate includes a hologram element that is a first hologram element including two or more diffraction cells, and a hologram element that is a second hologram element including a single diffraction cell.

Abstract: An optical system includes: a projection optical system for projecting an image light ray output from a display element and forming an image; and a light guide including an in-coupling region for guiding the ray to an inside of the guide and allowing it to travel in a first axis direction within the guide, and a propagation region for allowing the ray from the in-coupling region to propagate in the direction of the first axis, and allowing part of the ray to travel in a predetermined direction including a directional component of a second axis perpendicular to the first axis. In an optical path of the ray, a distance from the projection optical system to an entrance pupil of the projection optical system relative to the element in a plane perpendicular to the first axis is longer than a distance from the projection optical system to the in-coupling region.