Abstract: A head-up display device virtually displays an image to be viewable by an occupant by projecting the image on a projection member located above an instrument panel of a vehicle in a vehicle upward direction. Assuming that a direction along an up-down direction of the vehicle when the image is virtually displayed is defined as a vertical direction of the image, the head-up display device includes a projector that projects an image as light polarized in a polarization direction intersecting the vertical direction of the image and a reflecting mirror that reflects and redirects the light of the image from the projector toward the projection member, on an optical path between the projector and the projection member, and has a difference between S polarization reflectance and P polarization reflectance for the light from the projector.

Abstract: A light guide unit has a cold mirror unit to guide display light toward a projection window. In an XYZ color system, a wavelength region between a wavelength at which a value of a color matching function Z is maximum and a wavelength at which a value of the color matching function Y is maximum is a first wavelength region, and a wavelength region between a wavelength at which a value of a color matching function Y is maximum and a wavelength at which a value of a color matching function X is maximum is a second wavelength region. A minimum reflectance of the cold mirror unit to the display light takes a minimum value among reflectances of the respective wavelengths in a corresponding wavelength region. The minimum reflectance in the second wavelength region is larger than the minimum reflectance in the first wavelength region.

Abstract: A head-up display device projects display light of an image on a projection member to virtually display a virtual image of the image. An illumination light source unit emits an illumination light. An image display panel causes the illumination light from the illumination light source unit to pass therethrough to be emitted as a display light from a display surface to display the image. A projection lens is located between the illumination light source unit and the image display panel and projects the illumination light from the illumination light source unit onto the image display panel. The image display panel is tilted so that a normal direction to the display surface intersects with an optical axis of the illumination light source unit. The projection lens is tilted so that a radial direction of the projection lens coincides with a tangential direction to the display surface.

Abstract: A lighting unit includes a light source configured to radiate a light, a circuit board on which the light source is mounted, and multiple stages of condenser lenses configured to condense the radiation light radiated from the light source. A first-stage lens that is located closest to the light source and given a maximum positive power among the multiple stages of condenser lenses has a partition wall portion and a positioning portion. The partition wall portion partitions an accommodation space in which the light source is accommodated in a range from a composite focal point of the multiple stages of condenser lenses to the first-stage lens by projection toward the circuit board side. The positioning portion 222 is provided on the partition wall portion and positioned relative to the circuit board by concavo-convex fitting.

Abstract: A light guide unit guides a display light toward a projection member. A multilayer film filter unit transmits the display light with an optical multilayer film and shields an external light incident from a projection window. In the XYZ color system, a first wavelength region is between a wavelength having a maximum value of a color matching function Z and a wavelength having a maximum value of a color matching function Y. A second wavelength region is between the wavelength having the maximum value of the color matching function Y and a wavelength having a maximum value of a color matching function X. A minimum transmittance of the multilayer film filter unit to the display light takes a minimum value among transmittances of respective wavelengths in a target wavelength region. The minimum transmittance in the first wavelength region is smaller than that in the second wavelength region.

Abstract: An illumination unit includes a plurality of sets of illumination modules each having a light source placed at a conjugate position and a plurality of stages of condenser lenses that collect light from the light source toward a display device, a magnifying optical system being between the conjugate position and a viewing area. Each illumination module set includes an initial stage lens as a condenser lens closest to the light source and a final stage lens as a condenser lens farthest from the light source. In each illumination module set, assuming a composite focal point of a composite lens combined from all stages of condenser lenses, a gap between a principal plane of the initial stage lens and the light source is set to be equal to or less than a gap between the principal plane and the composite focal point.

Abstract: A head-up display device is configured to project a display light, which is to be reflected by a concave image forming reflection surface, onto a combiner having the image forming reflection surface a combiner to display a virtual image visible to an occupant. The combiner is located above an upper surface portion of the instrument panel. The projector is configured to project a display light in the form of a light beam. A light guide mirror has a light guide reflection surface and is configured to reflect the display light from the projector toward the image forming reflection surface. The light guide reflection surface is convex.

Abstract: An illumination lens condenses a light from a light source and emits the light toward a display to illuminate the display. The illumination lens includes multiple first lens surface parts having a shape obtained by extracting multiple portions of a first virtual lens surface along a first optical axis, the first virtual lens surface defining the first optical axis on which the light source is disposed and being at least twice differentiable between optical axes arranged in a reference direction, and multiple second lens surface parts having a shape obtained by extracting multiple portions of a second virtual lens surface along a second optical axis, the second virtual lens surface defining the second optical axis and being at least once differentiable between the optical axes arranged in the reference direction. The first lens surface parts and the second lens surface parts are alternately arranged in the reference direction.

Abstract: A head up display device mounted in a moving body uses a source light to project an image onto a projection member to display a virtual image so that the image is visible to a passenger, the projection member including a first transparent plate that maintains polarization state and has a first surface facing the passenger, a second transparent plate that maintains polarization state and has a second surface opposite to the first surface, and a waveplate interposed between the first and seconds transparent plates and including a fast axis and a slow axis that delays phase with respect to the fast axis, wherein the source light is emitted toward the first surface obliquely along a plane of incidence, the source light including an s-polarization component and a p-polarization component, and the slow axis of the waveplate is inclined with respect to the plane of incidence.

Abstract: A head-up display device reflects a display light on a projection member to display a virtual image. A light condensing unit causes condensation and collimates an illumination light from a light source unit. A liquid crystal element includes forms an image illuminated with the illumination light. The liquid crystal element emits the display light of the image in a light flux form in an emission direction corresponding to an incident direction of the illumination light. A positive optical element has a positive refractive power. A negative optical element has a negative refractive power. Both of the optical elements are located on the optical path and guide the display light from the liquid crystal element toward the projection member to enlarge a virtual image. The negative optical element on the optical path is located closer to the liquid crystal element than the positive optical element.

Abstract: An illumination light from each light emitting device illuminates a corresponding region of an image forming unit to form an image. A light condensing unit has multiple lens elements paired with the respective light emitting devices. Each condenser lens element has a light condensing surface to condense the illumination light. A z-direction is a direction connecting a surface vertex of the light condensing surface with the light emitting device paired with the surface vertex. An x-direction and a y-direction are orthogonal to each other on a virtual plane orthogonal to the z-direction. The pair of the condenser lens element and the light emitting device is aligned in at least one of the x-direction and the y-direction. Each light condensing surface is formed in a convex shape in which a curvature in the x-direction and a curvature in the y-direction are different from each other.

Abstract: Light emitting devices are aligned along one alignment direction. A first diffusion plate diffuses the illumination light from each of the light emitting devices. A condensing unit exerts a condensing action on the illumination light diffused with the first diffusion plate in a vertical direction perpendicular to the alignment direction. An image forming unit has an illumination target surface illuminated with the illumination light, which is condensed with the condensing unit, and allows a part of the illumination light incident on the illumination target surface to pass therethrough to form the image and to emit display light of the image as a light flux. A second diffusion plate is located on an optical path between the condensing unit and the image forming unit to again diffuse the illumination light condensed with the condensing unit and to cause the diffused illumination light to incident on the illumination target surface.

Abstract: A HUD apparatus is mounted to a vehicle and displays a virtual image visible to an occupant by projecting an image onto a windshield. The HUD apparatus includes multiple illumination units arrayed one another and providing illumination, and an image forming portion having an illumination target surface and forming the image when the respective illumination units illuminate corresponding spots on the illumination target surface. Each illumination unit has a light emitting element emitting illumination light with an emission angle distribution, according to which emission intensity reaches maximum in a peak direction and decreases with distance from the peak direction, and a condensing portion located face-to-face with the light emitting element and capturing a part of radiant flux including light in the peak direction PD from illumination light and collimating the captured part of radiant flux by condensing the captured part of radiant flux.

Abstract: An illumination unit includes a plurality of sets of illumination modules each having a light source placed at a conjugate position and a plurality of stages of condenser lenses that collect light from the light source toward a display device, a magnifying optical system being between the conjugate position and a viewing area. Each illumination module set includes an initial stage lens as a condenser lens closest to the light source and a final stage lens as a condenser lens farthest from the light source. In each illumination module set, assuming a composite focal point of a composite lens combined from all stages of condenser lenses, a gap between a principal plane of the initial stage lens and the light source is set to be equal to or less than a gap between the principal plane and the composite focal point.

Abstract: A projector projects a polarized light of an image. A light guide portion guides the light toward a projection member. A polarizing plate on an optical path has a transmission axis along which transmittance of the polarized light becomes maximum. An image longitudinal direction is along a vertical direction of a vehicle. An image lateral direction is perpendicular to the image longitudinal direction. A projection polarization azimuth angle is an azimuth angle of a polarization direction of the light relative to the image lateral direction. A transmission axis azimuth angle is an azimuth angle of the transmission axis of the polarizing plate relative to the image lateral direction. The polarizing plate makes the projection polarization azimuth angle different from the transmission axis azimuth angle to tilt the polarization direction of the light of the image relative to both of the image longitudinal direction and the image lateral direction.

Abstract: An illumination lens condenses a light from a light source and emits the light toward a display to illuminate the display. The illumination lens includes multiple first lens surface parts having a shape obtained by extracting multiple portions of a first virtual lens surface along a first optical axis, the first virtual lens surface defining the first optical axis on which the light source is disposed and being at least twice differentiable between optical axes arranged in a reference direction, and multiple second lens surface parts having a shape obtained by extracting multiple portions of a second virtual lens surface along a second optical axis, the second virtual lens surface defining the second optical axis and being at least once differentiable between the optical axes arranged in the reference direction. The first lens surface parts and the second lens surface parts are alternately arranged in the reference direction.

Abstract: An illumination unit includes a plurality of sets of illumination modules each having a light source placed at a conjugate position and a plurality of stages of condenser lenses that collect light from the light source toward a display device, a magnifying optical system being between the conjugate position and a viewing area. Each illumination module set includes an initial stage lens closest to the light source and a final stage lens farthest from the light source. In a surrounding illumination module of the illumination module sets, principal points of all stages of condenser lenses are positioned on a surrounding principal ray that passes through a periphery of an angle of view center of the display device to reach the viewing area, and the light source is positioned on the surrounding principal ray by being offset from a light axis of the initial stage lens in the reference direction.

Abstract: An illumination unit includes a plurality of sets of illumination modules each having a light source placed at a conjugate position and a plurality of stages of condenser lenses that collect light from the light source toward a display device, a magnifying optical system being between the conjugate position and a viewing area. Each illumination module set includes an initial stage lens as a condenser lens closest to the light source and a final stage lens as a condenser lens farthest from the light source. In each illumination module set, assuming a composite focal point of a composite lens combined from all stages of condenser lenses, a gap between a principal plane of the initial stage lens and the light source is set to be equal to or less than a gap between the principal plane and the composite focal point.

Abstract: A head-up display device that displays a virtual image to be viewable by an occupant in a movable body includes: a light source part which emits light source light; a liquid crystal panel integrally having a pair of polarizers for liquid crystals and a liquid crystal layer disposed between the polarizers in a stacked state; and an additional polarizer arranged in an optical path between the light source part and the liquid crystal panel. The additional polarizer and the pair of polarizers for liquid crystals have properties of transmitting polarized light along a transmission axis and shielding polarized light along a shielding axis which intersects the transmission axis. The additional polarizer is arranged such that the transmission axis and the shielding axis respectively match those of a polarizer for liquid crystals adjacent to the light source part, of the pair of polarizers for liquid crystals.

Abstract: A head-up display device includes an illumination optical system, an imaging optical system and a reflective optical system. The illumination optical system emits a source light indicating information. The imaging optical system projects the source light to a projection surface. The reflective optical system has a dielectric multilayer film, and is configured so that a retardation of a subject wavelength including at least a part of wavelengths of the source light from the illumination optical system is in a range greater than ??/2 [rad] and smaller than ?/2 [rad]. The reflective optical system is arranged on a path from the illumination optical system to the imaging system so that a polarization axis of the source light from the illumination optical system defines an angle ? satisfying a relation of 0 degree <?<90 degrees <?<180 degrees, relative to an incident surface.