Projection systems and components thereof are described that are well suited to miniaturization. These systems and components may use one or more of the following features: a folded optical path, as in a reflective cavity or a beamsplitter; an illumination beam that is converging at the place where it impinges upon the spatial light modulator; a beamsplitter that uses opposed prisms of substantially different sizes; a beamsplitter whose obliquely disposed partial reflector defines a first rectangular reference space, and where at least a portion of the light source or at least a portion of the projector lens is disposed within such first rectangular reference space; a system in which a ratio of areas of the first rectangular reference space and a second rectangular reference space is within a specified range, where the second rectangular reference space is just large enough to encompass the optical components of the projector; a system in which the projector lens is small compared to the spatial light modulator.

A system for measuring speckle contrast includes: a head up display (HUD) system configured to output a predetermined image and having a first pixels per degree (PPD); an imaging colorimeter: having a field of view; positioned such that the predetermined image is in the field of view; having a second PPD that is at least 2.2 times greater than the first PPD of the HUD system; and configured to capture an image including the predetermined image; and a speckle contrast module configured to determine a speckle contrast of the HUD system based on the image.

A light source device according to the present disclosure includes a first light source section for emitting a first light flux, a second light source section for emitting a second light flux, a third light source section for emitting a third light flux, a first reflecting member, a second reflecting member for reflecting the second light flux, and a polarization combining element. With respect to the polarization combining element, the first light flux and the second light flux are light polarized in a first polarization direction, and the third light flux is light polarized in a second polarization direction, and the first and second reflecting members are disposed so that a distance between the first light flux and second light flux becomes smaller after incidence than before the incidence. The polarization combining element combines the first light flux, the second light flux, and the third light flux with each other.

A light source device according to an embodiment of the present disclosure includes: a first light source section that emits light in a first wavelength region; a wavelength conversion section that is disposed on an optical path of the light in the first wavelength region, and is excited by the light in the first wavelength region emitted from the first light source section to emit light in a second wavelength region different from the first wavelength region; a polarization separation element that is disposed between the first light source section and the wavelength conversion section, and separates incident light on the basis of polarization; and a color separation element that is disposed between the first light source section and the polarization separation element, and separates incident light on the basis of a wavelength region.

An illumination unit capable of reducing luminance unevenness in illumination light, a projection display unit, and a direct-view display unit each of which uses such an illumination unit. An illumination optical system includes one or more light sources each including a solid-state light-emitting device; and an optical member configured to allow light incident from the solid-state light-emitting device to pass therethrough and exit therefrom, and at least one of the chips in the one or more light sources is configured of a laser diode. The optical member includes an integrator including a first fly-eye lens on which light from the solid-state light-emitting device is incident and a second fly-eye lens on which light from the first fly-eye lens is incident, and uniformizing a luminance distribution of light in a predetermined illumination region illuminated with light incident from the solid-state light-emitting device. A major-axis direction of a luminance distribution shape of light incident on an incident plane of the first fly-eye lens is different from arrangement directions of the cells in the first fly-eye lens.

[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.

[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.

The laser projection apparatus includes a laser source, an optical engine and a projection lens. The laser source includes a base plate, a plurality of light-emitting components and a reflecting portion. The plurality of light-emitting components include a first light-emitting component and a second light-emitting component. The polarization direction of the laser beam emitted by one of the first light-emitting component and the second light-emitting component is parallel to the base plate, and the polarization direction of the laser beam emitted by another of the first light-emitting component and the second light-emitting component is perpendicular to the base plate. The reflecting prism is configured to change a polarization polarity of one of the laser beam with the polarization direction perpendicular to the base plate or the laser beam with the polarization direction parallel to the base plate.

An apparatus may include (1) a planar liquid-crystal structure including a plurality of liquid crystals, and (2) a plurality of electrodes coupled to the planar liquid-crystal structure such that (a) when a first plurality of voltages are applied to at least some of the plurality of electrodes, the plurality of liquid crystals are oriented such that the planar liquid-crystal structure operates as a diffraction grating having a first pitch, and (2) when a second plurality of voltages are applied to at least some of the plurality of electrodes, the plurality of liquid crystals are oriented such that the planar liquid-crystal structure operates as a diffraction grating having a second pitch different from the first pitch.