Abstract: Provided is a head-up display including a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, a backlight that emits light toward the Fresnel lens, a light-transmissive member between the backlight and the Fresnel lens, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space, where a length of the liquid-crystal panel in a longitudinal direction of the head-up display is longer than a length of the light-transmissive member in the longitudinal direction.

Abstract: An optical circuit element capable of preventing stray light propagated through a part including a substrate of the optical circuit element from being emitted to the outside is provided. The optical circuit element has a substrate, an optical waveguide layer that is formed on one surface of the substrate, and a protective layer that is overlaid on the optical waveguide layer. The optical waveguide layer has an optical waveguide configured for light to be propagated therethrough. A groove portion, which reaches to a position deeper than the one surface from a surface of the protective layer toward the substrate, is formed. The optical circuit element further includes a light absorption layer that covers at least a bottom surface and a side surface of the groove portion.

Abstract: An optical waveguide element includes: an optical waveguide having a ridge part and a slab part having a thickness less than the ridge part. The optical waveguide includes: a first waveguide having a first ridge with and a first slab film thickness; a second waveguide having a second ridge width and a second slab film thickness; a first intermediate waveguide connected to the first waveguide and having a third ridge width and the first slab film thickness; and a second intermediate waveguide connected to the second waveguide and having a fourth ridge width and the second slab film thickness. The first waveguide, the first intermediate waveguide, the second intermediate waveguide, and the second waveguide are arranged in this order; the second slab film thickness is larger than the first slab film thickness; and the third ridge width is larger than the fourth ridge width.

Abstract: To provide an optical modulation element whereby reduced drive voltage and suppression of DC drift can be obtained at the same time. An optical modulation element includes: a substrate; and an optical waveguide formed of an electrooptic material film formed on the substrate and having a ridge part which is a protruding portion, and a slab part having a smaller film thickness than the ridge part 11r. The optical waveguide includes a first waveguide part having a first ridge width and a first slab film thickness and to which an RF signal is applied, and a second waveguide part having a second ridge width and a second slab film thickness different from the first slab film thickness and to which a DC bias is applied.

Abstract: To provide an optical modulation element capable of suppressing electrode loss at a low frequency of 50 GHz or less, and suppressing radiation loss at a high frequency of 50 GHz or more. An optical modulation element comprises: a substrate; and at least one interaction part provided on the substrate. The interaction part includes: first and second optical waveguides formed adjacent to each other on the substrate; and first and second signal electrodes provided so as to oppose the first and second optical waveguides respectively. o ground electrode is provided in a nearby region of the interaction part, and a ground electrode is provided in the vicinity of at least one of an input part and a terminal part electrically connected to each of the first and second signal electrodes.

Abstract: An optical modulator includes a plurality of optical modulation units having a Mach-Zehnder type optical waveguide consisting of two optical waveguides and a high-frequency line pair arranged along the two optical waveguides and consisting of two signal electrodes for applying a pair of differential high-frequency signals, and a plurality of high-resistance conductive films are provided between adjacent high-frequency line pairs separated from the high-frequency line pair.

Abstract: To prevent deterioration in an extinction ratio due to asymmetry between a pair of optical waveguides. An optical modulator has a Mach-Zehnder optical waveguide including mutually parallel first and second waveguides and a signal electrode for controlling the phase of light propagating in the Mach-Zehnder optical waveguide. The first and second waveguides have a first section in which the second waveguide has a line width smaller than that of the first waveguide and a second section in which the first waveguide has a line width smaller than that of the second waveguide. The first section and the second section are replaced with each other in curved parts.

Abstract: A head-up display includes a liquid-crystal panel including a display screen provided at a front surface thereof, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, a backlight that emits light toward the Fresnel lens, a light-transmissive member between the backlight and the Fresnel lens, a body part accommodating the Fresnel lens, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space. The body part has a step-shaped structure including a first step surface and a second step surface, the first and second step surfaces are oriented in the same direction as the front surface of the liquid-crystal panel. The first step surface is located on the liquid-crystal panel side from the second step surface.

Abstract: Provided is a head-up display including a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion member between the liquid-crystal panel and the heat-transfer member, a backlight that emits light toward the heat-transfer member, a heat sink disposed along at least one side of the Fresnel lens and one side of backlight, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space, where a light-diffusion structure is provided to a surface of the light-diffusion member facing the liquid-crystal panel.

Abstract: Provided is a head-up display including a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, a backlight that emits light toward the light-transmissive member, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space, where the light-diffusion structure includes a plurality of fine particles and an average particle size of the plurality of fine particles is equal to or smaller than 20 um.

Abstract: Provided is a head-up display including a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space, where the light-diffusion structure is thinner than the Fresnel lens, and the light-diffusion structure has a thickness equal to or smaller than 300 ?m.

Abstract: Provided is a head-up display including a display system that has a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, and a backlight that emits light toward the Fresnel lens. The head-up display also includes a first mirror that reflects light from the display system, a second mirror that reflects light from the first mirror, and a control circuit that controls the liquid-crystal panel, where a center of the second mirror is closer to a center of the control circuit than a center of the display system in a direction connecting a center of the first mirror and the center of the second mirror.

Abstract: Provided is a head-up display including a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, a backlight that emits light toward the Fresnel lens, a light-transmissive member between the backlight and the Fresnel lens, a body part accommodating the light-transmissive member, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space, where a surface of the Fresnel lens facing the backlight is uneven.

Abstract: Provided is a head-up display including a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, a backlight that emits light toward the Fresnel lens, a light-transmissive member between the backlight and the Fresnel lens, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space, where a length of the liquid-crystal panel in a longitudinal direction of the head-up display is longer than a length of the light-transmissive member in the longitudinal direction.

Abstract: Provided is a head-up display including a liquid-crystal panel including a display screen provided at a front surface thereof, a Fresnel lens opposite the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, a backlight that emits light toward the Fresnel lens, a body part accommodating the Fresnel lens, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space. The body part has a step-shaped structure including a first step surface and a second step surface, the first step surface and the second step surface are oriented in the same direction as the front surface of the liquid-crystal panel, the first step surface is located on the liquid-crystal panel side from the second step surface, and the liquid-crystal panel is supported on the second step surface.

Abstract: A projection device includes: a plurality of light sources arranged in a first direction; a spatial modulation element that modulates incident light into image information and emits the image information; a lens that changes an optical path of light emitted from each of the plurality of light sources such that the light emitted from each light source reaches substantially the same region of an incident surface of the spatial modulation element; and a first reflective optical member that deflects the light emitted from the lens toward the spatial modulation element, the first reflective optical member having a shape that reflects light emitted from the lens so as to be incident on an arbitrary point on the incident surface of the spatial modulation element at a predetermined reference incident angle.

Abstract: A vane pump including a housing having a peripheral wall portion, a bottom wall portion, and a pump chamber; a rotor disposed in the pump chamber to be rotatable; a vane disposed to be slidable in the radial direction with respect to the rotor and partitioning the pump chamber into working chambers; and a reed valve that opens and closes a discharge hole of the bottom wall portion. A pressure relief groove is disposed in a portion of the bottom wall portion corresponding to the discharge section with a clearance secured between the peripheral wall portion and the pressure relief groove. When the vane overlaps the pressure relief groove, a pair of the working chambers on both sides of the vane in the rotational direction communicates with each other via the pressure relief groove.

Abstract: Provided is a head-up display including a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion member between the liquid-crystal panel and the Fresnel lens, a backlight emitting light toward the Fresnel lens, a heat sink accommodating the light-diffusion member, the backlight and the Fresnel lens, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space, where a surface of the Fresnel lens facing the backlight is uneven.

Abstract: A vane pump includes a housing, a rotor, a vane and a reed valve. A position at which the sliding direction of the vane with respect to the rotor is inverted from outward to inward is defined as a reference position, and a section of the pump chamber on the discharge hole side with respect to the reference position is defined as a discharge section. A pressure relief groove is disposed in a portion of the bottom wall portion corresponding to the discharge section with a clearance secured between the peripheral wall portion and the pressure relief groove. When the vane overlaps the pressure relief groove, a pair of the working chambers communicate with each other via the pressure relief groove.

Abstract: Provided is a display that includes a liquid-crystal panel, a heat-transfer member, and a light-diffusion member between the liquid-crystal panel and the heat-transfer member. The display includes a liquid-crystal panel, a heat-transfer member, and a light-diffusion structure. The liquid-crystal panel includes a display screen. The heat-transfer member is light-transmissive. The heat-transfer member is on an opposite side of the liquid-crystal panel from the display screen.