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.

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.

A cooling device includes a thermally conductive housing member that houses a heat generating body, a first air blower that generates first cooling wind flowing along the housing member through the heat generating body inside the housing member, and a second air blower that generates second cooling wind flowing along the housing member outside the housing member.

A cooling device includes a thermally conductive housing member that houses a heat generating body, a first air blower that generates first cooling wind flowing along the housing member through the heat generating body inside the housing member, and a second air blower that generates second cooling wind flowing along the housing member outside the housing member.

[Solving Means] A projector includes a first light-emitting side polarization plate, a second light-emitting side polarization plate, a third light-emitting side polarization plate, and a cross dichroic prism. The first light-emitting side polarization plate is arranged on a light-emitting side of a first liquid crystal lightbulb that modulates light of a first wavelength band. The second light-emitting side polarization plate is arranged on a light-emitting side of a second liquid crystal lightbulb that modulates light of a second wavelength band. The third light-emitting side polarization plate is arranged on a light-emitting side of a third liquid crystal lightbulb that modulates light of a third wavelength band. The liquid crystal lightbulb includes a first side surface that light of the first wavelength band enters and opposes the first light-emitting side polarization plate, a second side surface that light of the second wavelength band enters and opposes the second light-emitting side polarization plate, a third side surface that light of the third wavelength band enters and opposes the third light-emitting side polarization plate, and a fourth side surface from which synthetic light obtained from the light of the first wavelength band, the second wavelength band, and the third wavelength band is emitted. At least one of the first light-emitting side polarization plate, the second light-emitting side polarization plate, and the third light-emitting side polarization plate is tilted with respect to the opposing side surface.

A projector according to the present technology includes a blower mechanism, a liquid crystal lightbulb, a light-incident-side polarization plate, and a light-emitting-side polarization plate. The blower mechanism generates a cooling wind. The light-incident-side polarization plate includes a plurality of wires formed to extend non-parallel to the cooling wind blown by the blower mechanism and is arranged on a light-incident side of the liquid crystal lightbulb. The light-emitting-side polarization plate includes a plurality of wires formed to extend non-parallel to the cooling wind blown by the blower mechanism and is arranged on a light-emitting side of the liquid crystal lightbulb.

A projector according to the present technology includes a blower mechanism, a liquid crystal lightbulb, a light-incident-side polarization plate, and a light-emitting-side polarization plate. The blower mechanism generates a cooling wind. The light-incident-side polarization plate includes a plurality of wires formed to extend non-parallel to the cooling wind blown by the blower mechanism and is arranged on a light-incident side of the liquid crystal lightbulb. The light-emitting-side polarization plate includes a plurality of wires formed to extend non-parallel to the cooling wind blown by the blower mechanism and is arranged on a light-emitting side of the liquid crystal lightbulb.

[Solving Means] A projector according to the present technology includes a lightbulb, a projection section, and a replacement mechanism. The lightbulb modulates light. The projection section projects light modulated by the lightbulb. The replacement mechanism holds a transmissive member arranged on an optical path between the lightbulb and the projection section and is capable of replacing the transmissive member.

[Solving Means] A projector according to the present technology includes a lightbulb, a projection section, and a replacement mechanism. The lightbulb modulates light. The projection section projects light modulated by the lightbulb. The replacement mechanism holds a transmissive member arranged on an optical path between the lightbulb and the projection section and is capable of replacing the transmissive member.

A wavelength conversion module including a substrate, a wavelength conversion layer and at least one wing is provided. The substrate has a wavelength conversion area, a non-wavelength conversion area and at least one through hole. The through hole penetrates through the substrate and is located in the non-wavelength conversion area. The wavelength conversion layer is disposed in the wavelength conversion area of the substrate. The wing is disposed in the non-wavelength conversion area of the substrate. When the substrate reaches a first temperature range, the wing closes the through hole. When the substrate reaches a second temperature range, at least one airflow channel is formed between the wing and the through hole. The wavelength conversion module of the invention and the projection device using the same effectively reduce a temperature of the wavelength conversion module, and thus have better reliability.