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 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 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 head-up display is configured to project an image on a transparent reflection member to cause an observer to visually recognize a virtual image, and includes a display device configured to display the image, and a projection optical system configured to project the image displayed by the display device as the virtual image for the observer. The projection optical system is configured to form an image as an intermediate image, and includes a first lens configured to condense light, and a first optical element configured to diffuse light. The first lens and the first optical element are disposed in this order along an optical path from the display device. The first lens is inclined with respect to a reference beam which is defined as a beam reaching a center of a viewpoint region of the observer and corresponding to a center of the virtual image.

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: A head-up display is configured to project an image on a transparent reflection member to cause an observer to visually recognize a virtual image, and includes a display device configured to display the image, and a projection optical system configured to project the image displayed by the display device as the virtual image for the observer. The projection optical system is configured to form an image as an intermediate image, and includes a first lens configured to condense light, and a first optical element configured to diffuse light. The first lens and the first optical element are disposed in this order along an optical path from the display device. The first lens is inclined with respect to a reference beam which is defined as a beam reaching a center of a viewpoint region of the observer and corresponding to a center of the virtual image.

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.

Abstract: A head-up display system includes a display that emits a light flux and a light guide body that guides the light flux to the light-transmitting member. A light beam at a center of the light flux emitted from the display is incident while being inclined with respect to a normal direction of the incident surface of 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, the light flux is replicated into a plurality of light fluxes in a horizontal direction of the virtual image, and then the replicated light fluxes are further replicated in a vertical direction of the virtual image to be emitted from the emission surface so as to expand the visual recognition region. A light beam at a center of the light fluxes emitted from the light guide body is emitted toward the light-transmitting member while being inclined with respect to a normal direction of the emission surface of the light guide body.

Abstract: A head-up display system includes a display that emits a light flux visually recognized by an observer as the virtual image, and a light guide body that guides the light flux to the light-transmitting member. 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, the light flux is replicated into a plurality of light fluxes in a direction perpendicular to a horizontal direction of the virtual image visually recognized by the observer to be emitted from the emission surface so as to expand a visual recognition region.

Abstract: A head-up display of the present disclosure projects a display image on a transparent reflecting member. The head-up display includes: a display device that displays the display image; and a projection optical system that projects the display image displayed on the display device. On an assumption that light reaching a center of a viewpoint region of the observer and corresponding to a center of the virtual image is reference light, the projection optical system includes a prism element that has an incident surface, a reflection surface, and an emitting surface different from the incident surface sequentially in an optical path from the display device. The emitting surface is inclined to the reference light. An inclination amount ?2 of the reference light emitted from the emitting surface with respect to the emitting surface lies in a range of 15°<|?2|<45° in the optical path from the display device.

Abstract: The optical system includes a first sub-optical system including an aperture stop and a second sub-optical system including a prism. The prism has a first transmission surface located on a reduction side, a second transmission surface located on a magnification side, and at least one reflection surface between the first transmission surface and the second transmission surface. The first sub-optical system includes a plurality of rotationally symmetric lens elements.

Abstract: A head-up display includes a display device and a projection optical system; the projection optical system includes first and second optical elements arranged in order of an optical path from the image; and when optical paths corresponding to an upper end and a lower end of the virtual image are defined as an upper ray and a lower ray, respectively, and a diverging effect and a converging effect are defined as being negative and positive, respectively, the first and the second optical elements satisfy conditional expressions P_u1?P_l1<0 and P_u2?P_l2>0 (where P_u1 denotes a local power of the first optical element acting on the upper ray, P_l1 denotes a local power of the first optical element acting on the lower ray, P_u2 denotes a local power of the second optical element acting on the upper ray, P_l2 denotes a local power of the second optical element acting on the lower ray).

Abstract: A head-up display is configured to project an image on a transparent reflection member to cause an observer to visually recognize a virtual image, and includes a display device configured to display the image, and a projection optical system configured to project the image displayed by the display device as the virtual image for the observer. The projection optical system is configured to form an image as an intermediate image, and includes a first lens configured to condense light, and a first optical element configured to diffuse light. The first lens and the first optical element are disposed in this order along an optical path from the display device. The first lens is inclined with respect to a reference beam which is defined as a beam reaching a center of a viewpoint region of the observer and corresponding to a center of the virtual image.

Abstract: An optical device includes a lens element, a first scanning element, and a controller. The lens element directs first light emitted from the first light-emitting element and second light emitted from the second light-emitting element, to a predetermined position. The first scanning element is arranged at the predetermined position, on which first light and second light exiting the lens element are incident at mutually different angles. The controller provides light emission control to start light emission at light emission timings shifted. The first light-emitting element and the second light-emitting element is arrayed such that an optical axis of first light and an optical axis of second light are contained in a same plane. The controller controlees the light emission timings of the first light-emitting element and the second light-emitting element in response to rotation actions of the first scanning element.

Abstract: The head-up display includes an imaging position changer configured to change a position of a virtual image between a far visual position far from an observer and a near visual position close to the observer. The imaging position changer inclines the virtual image at the far visual position by a second inclination angle with respect to a perpendicular plane to a reference light beam reaching a center of a viewpoint region in which a viewpoint of the observer is located, to move an upper end thereof in a forward direction of the moving object, and inclines the virtual image at the near visual position by a first inclination angle smaller than the second inclination angle with respect to the perpendicular plane to the reference light beam, to move the upper end in the forward direction of the moving object.

Abstract: A prism includes a first intermediate imaging position at which a component in a first direction of the light flux is imaged and a second intermediate imaging position at which a component in a second direction orthogonal to the first direction of the light flux is imaged, different from the first intermediate imaging position. At least one of the first intermediate imaging position and the second intermediate imaging position lying within a first range from the second surface between the first surface and the second surface or lying within a second range from the second surface between the second surface and the third surface. The first range has a length less than one-half of an optical path length from the first surface to the second surface, and the second range has a length less than one-half of the optical path length from the second surface to the third surface.

Abstract: A head-up display is configured to project an image on a transparent reflection member to cause an observer to visually recognize a virtual image, and includes a display device configured to display the image, and a projection optical system configured to project the image displayed by the display device as the virtual image for the observer. The projection optical system is configured to form an image as an intermediate image, and includes a first lens configured to condense light, and a first optical element configured to diffuse light. The first lens and the first optical element are disposed in this order along an optical path from the display device. The first lens is inclined with respect to a reference beam which is defined as a beam reaching a center of a viewpoint region of the observer and corresponding to a center of the virtual image.

Abstract: A head-up display of the present disclosure projects a display image on a transparent reflecting member. The head-up display includes: a display device that displays the display image; and a projection optical system that projects the display image displayed on the display device. On an assumption that light reaching a center of a viewpoint region of the observer and corresponding to a center of the virtual image is reference light, the projection optical system includes a prism element that has an incident surface, a reflection surface, and an emitting surface different from the incident surface sequentially in an optical path from the display device. The emitting surface is inclined to the reference light. An inclination amount ?2 of the reference light emitted from the emitting surface with respect to the emitting surface lies in a range of 15°<|?2|<45° in the optical path from the display device.

Abstract: A head-up display is configured to project an image on a transparent reflection member to cause an observer to visually recognize a virtual image, and includes a display device configured to display the image, and a projection optical system configured to project the image displayed by the display device as the virtual image for the observer. The projection optical system is configured to form the image as an intermediate image, and includes a first optical element configured to condense light, a first lens configured to condense light, and a second optical element configured to diffuse light. The first optical element, the first lens, and the second optical element are disposed in this order along an optical path from the display device.

Abstract: A display apparatus includes a display unit that projects an image to a light transmissive display member. The display unit is configured to accommodate a display device and a projection optical system that projects the image displayed on the display device to the display member in a housing including an opening through which projected light is output. The projection optical system includes a first reflecting member disposed on a display device side and a second reflecting member disposed on an opening side in an optical path extending from the display device to the opening. A reflection surface of the first reflecting member that reflects the image displayed on the display device has a convex shape of a free-form surface, and a reflection surface of the second reflecting member that projects the image to the display member has a concave shape of a free-form surface.