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 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.

A new projector design combines one spatial light modulator that affects only the phase of the illumination, and one spatial light modulator that only affects its amplitude (intensity). The phase-only modulator curves the wavefront of light and acts as a pre-modulator for a conventional amplitude modulator. This approach works with both white light and laser illumination, generating a coarse image representation efficiently, thus enabling, within a single image frame, significantly elevated highlights as well as darker black levels while reducing the overall light source power requirements.

[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.

An efficient conjugate lighting system for an LCD projector, includes an LED light source, a square cone condenser, a collimating lens, a quarter-wave plate, a brightness-enhancing polarizer, an LCD light valve, a field lens and a projection lens which are provided in sequence according to a direction of light travel; wherein the efficient conjugate lighting system for the LCD projector further comprises a reflecting mirror provided at an entrance port of the square cone condenser; a light-transmitting surface of the entrance port of the square cone condenser is bisected along a horizontal centerline or a vertical centerline to form a first sub-light-transmitting surface and a second sub-light-transmitting surface; a light-emitting surface of the LED light source is provided on the first sub-light-transmitting surface, and the reflector is provided on the second sub-light-transmitting surface.

An optical apparatus is configured to introduce light from an object to an image pickup element, and includes first, second, and third retardation plates, a polarizer, and a setter. The first retardation plate, the second retardation plate, and the polarizer are arranged in this order from a side of the object to a side of the image pickup element. The slow axis direction or the fast axis direction of the second retardation plate tilts to the slow axis direction or the fast axis direction of the first retardation plate. The setter sets the retardation of the second retardation plate according to the polarization component of the light from the object.

An optical arrangement for expanding and uniformizing a beam of light, including a first optical member arranged to receive a collimated incoming light beam, from an incoming beam direction, with a first polarization, the first optical member configured to expand and uniformize the collimated incoming light beam along a first axis to form a first collimated light beam exiting therefrom in a first beam direction; a second optical member adapted to receive the first collimated light beam, from the first beam direction, with the first polarization in relation thereto, the second optical member configured to expand and uniformize the first collimated light beam along a second axis to form a second collimated light beam exiting therefrom in a second beam direction.