A coaxial laser light source apparatus includes at least one laser light source module, a beam homogenizer, and optical path adjusting elements. The laser light source module includes multiple laser light sources arranged along a first direction, and each of the laser light sources is configured to emit a laser light along a second direction. The first direction is substantially perpendicular to the second direction, and the laser lights have different properties. The laser lights travel along the second direction toward the beam homogenizer coaxially. The optical path adjusting elements are located between the laser light sources and the beam homogenizer, and the optical path adjusting elements are configured to adjust traveling directions of the laser lights.

A laser light source depolarizer includes a laser light source, a light angle adjusting element, a birefringent crystal, and an integration rod. The laser light source is configured to emit a laser light. The light angle adjusting element is configured to change the diffusion angle of the laser light. The light angle adjusting element is disposed between the laser light source and the birefringent crystal. The birefringent crystal is disposed between the light angle adjusting element and the integration rod, and the birefringent crystal is configured to break the polarity of the laser light.

A prism block includes a first prism having first, second and third surfaces, a second prism having a fourth surface parallel to the first surface, a fifth surface facing the second surface, and a sixth surface, a third prism having seventh and eight surfaces respectively facing the second and fifth surfaces, and an optical path separation coating disposed between the fifth and eighth surfaces. Illumination light incident on the third surface is reflected by the second surface, and is emitted from the first surface. Projection light incident on the first surface is emitted from the fourth surface. Imaging light incident on the fourth surface is reflected by the optical path separation coating, and is emitted from the sixth surface. A projection axis plane including optical paths of the illumination light and the projection light, and an imaging axis plane including an optical path of the imaging light intersect each other.

A lighting device of the present disclosure includes a light source device and a reflective component. The reflective component reflects an illumination light incident from the light source device off the reflecting surface of the reflective component at incident angle α, and emits the illumination light reflected toward a display element at exit angle β. The reflecting surface of the reflective component is rotated with respect to two axes orthogonal to each other. 20 degrees≤|α−β|≤60 degrees is satisfied. Where, each of the incident angle α and the exit angle β is angle of the illumination light to a horizontal direction of the display element when the illumination light is incident on a front surface of the display element.

A reflector includes a reflective film and a substrate, wherein the reflective film is attached to the substrate. Also, an optical system of an LCD (liquid crystal display) projector includes a first reflector, a second reflector, an LED (light emitting diode) light source, a condenser, a collimating lens, an LCD light valve, a field lens and a projection lens, wherein the LED light source, the condenser, the first reflector, the collimating lens, the LCD light valve, the field lens, the second reflector and the projection lens are set in sequence according to a direction of light. The reflector is significantly improved in the reflection efficiency while maintaining the low cost, or the reflector is significantly reduced in the manufacturing cost while achieving the high reflection efficiency, so that the output brightness and the photoelectric efficiency of the projector including the reflector with low cost, which has a very positive effect.

A display for displaying an image to a viewer includes an image generator having an illumination subsystem generating illumination of at least a first color, the image generator employing the illumination to generate an image. Projection optics projects illumination from the image for display to the viewer. The illumination subsystem includes a first laser generating a first laser beam of the first color with a first polarization and a second laser generating a second laser beam of the first color with a second polarization. The first and second polarizations are orthogonal at at least one location within the projection optics, thereby projecting a quasi-unpolarized image.

An illumination system, including a housing, a first light source, a second light source, a polarization beam splitting element, and a heat dissipation module, is provided. The first light source and the second light source are disposed in the housing and are respectively configured to provide a first beam to the polarization beam splitting element along a first optical axis and a second beam to the polarization beam splitting element along a second optical axis. A portion of an inner surface of the housing has a light absorption region. The light absorption region is configured to absorb the first beam that is not reflected by the polarization beam splitting element and the second beam that does not penetrate the polarization beam splitting element, so as to convert them into heat. The heat generated by the light absorption region is dissipated by the heat dissipation module.

An image display apparatus according to an embodiment of the present technology includes a polarizer, a polarization conversion element, and a ¼ wave plate. The polarizer causes to transmit linearly polarized light having a predetermined polarization direction. The polarization conversion element converts a polarization state of the linearly polarized light transmitted through the polarizer and emits the light as light in a non-polarized state. The ¼ wave plate is arranged on an optical path of the light in the non-polarized state emitted from the polarization conversion element.

In a first period, an optical apparatus converts first light that exits out of a retardation film into light polarized in a first polarization direction and converts second light that exits out of the retardation film into light polarized in a second polarization direction, and in a second period, the optical apparatus converts the first light that exits out of the retardation film into light polarized in the second polarization direction and converts the second light that exits out of the retardation film into light polarized in the first polarization direction.

A structured light projector includes a light source configured to emit light, a structured light pattern mask configured to receive the light emitted by the light source and including a first region configured to generate a first structured light having a first polarization and a second region configured to generate a second structured light having a second polarization that is different from the first polarization, and a polarization multiplexing deflector configured to deflect the first structured light and the second structured light generated by the structured light pattern mask, to different directions, respectively.