Provided is a polarization splitting device. The polarization splitting device includes a first optical element. The first optical element comprises a light incident surface, a polarization splitting interface and a reflective interface, and the polarization splitting interface and the reflective interface are correspondingly arranged. Incident light enters the first optical element through the light incident surface, and is split into first light and second light through the polarization splitting interface; the first light is incident on the reflective optical element after being reflected by the reflective interface: and the second light exits from the first optical element after being transmitted through the polarization splitting interface.

An optical system of the disclosure includes: a fluorescent unit that includes a phosphor region excited by a first color light beam to output fluorescent light including at least one color light beam, and outputs the first color light beam in a first period and outputs the fluorescent light in a second period; one or two light valves illuminated by at least one of the first color light beam or the fluorescent light; and a region division element including first and second regions and disposed on an optical path between the fluorescent unit and the one or two light valves, the first region outputting the first color light beam and the fluorescent light from the fluorescent unit to be able to reach the one or two light valves, the second region outputting the fluorescent light from the fluorescent unit to be able to reach the one or two light valves.

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.

To provide an optical element capable of realizing an increase in color range of videos and an improvement in brightness of the videos, a light source device including the optical element, and a projector including the light source device. Provided is an optical element including: a first color conversion layer; a second color conversion layer; and a heat insulating layer, in which the heat insulating layer is disposed between the first color conversion layer and the second color conversion layer, a light source device including the optical element, and a projector including the light source device.

Provided is a reflective screen and a projection image display system in which a transmittance of light can be selectively changed, a transmittance in a transparent state is sufficiently high, a voltage does not need to be applied constantly, and a voltage is applied to decrease a transmittance of light in a case where the reflective screen is irradiated with video light. The reflective screen includes: a light reflecting layer that is formed of a cholesteric liquid crystal layer and where a selective reflection wavelength at a polar angle of 60° is present in a visible range, in which senses of helix of all of cholesteric liquid crystal layers are the same and Expression (1) is satisfied; and a transparent first electrode, a transparent second electrode, and a light control layer that are provided on a rear side with respect to the light reflective layer, the light control layer being disposed between the first electrode and the second electrode, in which the light control layer includes a polymer network and liquid crystal molecules and changes between a first state where light is scattered and a second state where transmission of light is allowed by changing a magnitude of a voltage applied, the polymer network having a three-dimensional net shape having a plurality of domains, and the liquid crystal molecules being positioned in the domains.

R[−60,40](550)/R[−60,30](550)≥1.5  Expression (1)

A wavelength conversion element according to the present disclosure includes a wavelength conversion layer having a first surface having a recessed part, and a plurality of air holes, and configured to be excited by light in a first wavelength band to thereby generate light in a second wavelength band different from the first wavelength band, a particle disposed in the recessed part, a light transmissive member disposed so as to cover the recessed part and the particle, a reflecting layer disposed so as to be opposed to the first surface of the wavelength conversion layer, and a base member disposed so as to be opposed to the reflecting layer.

Dual or multi-modulation display system are disclosed that comprise projector systems with at least one modulator that may employ non-mechanical beam steering modulation. Many embodiments disclosed herein employ a non-mechanical beam steering and/or polarizer to provide for a highlights modulator.

[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.