An eyepiece for projecting an image to an eye of a viewer includes a waveguide configured to propagate light in a first wavelength range, and a grating coupled to a back surface of the waveguide. The grating is configured to diffract a first portion of the light propagating in the waveguide out of a plane of the waveguide toward a first direction, and to diffract a second portion of the light propagating in the waveguide out of the plane of the waveguide toward a second direction opposite to the first direction. The eyepiece furthers include a wavelength-selective reflector coupled to a front surface of the waveguide. The wavelength selective reflector is configured to reflect light in the first wavelength range and transmit light outside the first wavelength range, such that the wavelength-selective reflector reflects at least part of the second portion of the light back toward the first direction.

An eyepiece includes a planar waveguide having a front surface and a back surface. The eyepiece also includes a grating coupled to the back surface of the planar waveguide and configured to diffract a first portion of the light propagating in the planar waveguide out of a plane of the planar waveguide toward a first direction and to diffract a second portion of the light propagating in the planar waveguide out of the plane of the planar waveguide toward a second direction opposite to the first direction and a wavelength-selective reflector coupled to the front surface of the planar waveguide. The wavelength-selective reflector comprises a multilevel metasurface comprising a plurality of spaced apart protrusions having a pitch and formed of a first optically transmissive material and a second optically transmissive material disposed between the spaced apart protrusions.

Disclosed is a monolithic LCD projector, including: a light source, a polarizer provided on a light emitting side of the light source and configured for converting light emitted from the light source into linearly polarized light, an LCD panel provided on a light emitting side of the polarizer and configured for modulating the linearly polarized light according to an image signal to generate modulated light, an analyzer provided on a light emitting side of the LCD panel and separated from the LCD panel and obliqued, the analyzer includes a reflective polarizer and a functional structure, and a lens provided in a reflected light path of the analyzer and configured for projecting the second polarization state light reflected by the reflective polarizer.

An apparatus and a method for image display include a projection screen, a projection device, a control unit, and an imaging element. The projection screen is movable back and forth along an axis perpendicular to the projection face under control from the control unit. The control unit is configured to divide an image to be projected into a set of sub-images depending on distances, of one or more objects in the image, to be perceived by a user along the axis, and to control the projection screen and the projection device such that the projection device projects the set of sub-images onto the projection face when the projection face is moving to different positions respectively. The imaging optical element is configured to form a virtual image of the respective sub-image when the projection face is moving to the corresponding position.

A projector that modulates and projects light emitted from a light source includes an exterior housing configuring the exterior of the projector, a cooling target separably attached from the outside of the exterior housing, a cooling fan configured to deliver a cooling gas to the cooling target, and a channel forming member forming a part of a channel in which the cooling gas delivered from the cooling fan flows. In a state in which the cooling target is attached to the projector, the cooling target and the channel forming member form the channel. The cooling gas flows in the channel along the cooling target.

The purpose of the present technology is to provide a video projection device capable of obtaining a satisfactory video (image) while achieving reduction in power consumption and reduction in size of the device. Provided is a video projection device including at least: a monolithic semiconductor laser array including multiple light emitting units, each of which emits a laser light beam; an optical waveguide that guides the laser light beam in a predetermined direction; a mirror that scans the laser light beam in two axes; and a diffractive element that diffracts the laser light beam in a specific direction in front of an eye and projects the laser light beam on a retina. The multiple light emitting units are respectively optically coupled to different input ports among multiple input ports included in the optical waveguide.

A projector including a casing, a control system, an image assembly and at least one electric thermal heater is provided. The image assembly is coupled to and controlled by the control system. The electric thermal heater is coupled to and controlled by the control system. The control system is configured to activate the electric thermal heater to preheat the image assembly, such that the image assembly is warmed up to a cut-off temperature. Then, the control system is configured to switch off the electric thermal heater. Then the focal length of the image assembly is adjusted. A focal length adjusting method for the projector is further provided. The projector and the method may be used to avoid the thermal expansion of various elements, so as to avoid focal length shift.

A liquid crystal display element includes a pixel region which optically modulates received illumination light for each pixel. A heat sink dissipates heat of the liquid crystal display element. A first mask member is fixed to the heat sink, is formed of a material having a lower heat transfer rate than the heat sink, includes a first opening of which the size corresponds to the size of the pixel region, and masks unnecessary light. A second mask member is arranged at a position further away from the liquid crystal display element than the first mask member, is fixed to the heat sink, is formed of a material having a higher heat transfer rate than the first mask member, includes a second opening of which the size is equal to or larger than the size of the first opening, and masks the unnecessary light.

A projection type image display apparatus including a light source apparatus includes a light emitting element emitting blue light; a phosphor receiving the blue light to emit predetermined light; a heat sink provided with a bottom portion and a plurality of heat radiation fins extending from the bottom portion; and a cooling fan arranged to cool the plurality of heat radiation fins of the heat sink. The light emitting element is attached to the bottom portion of the heat sink. The phosphor is attached to the bottom portion of the heat sink at a predetermined interval from the light emitting element. Heat pipes conducting heat by repeating evaporation and liquefaction of working liquid are embedded in the bottom portion. The heat pipes are respectively provided with sections opposing the light emitting element in a thickness direction of the bottom portion.

Provided is an electro-optical device including an electro-optical panel that includes a display region, a holder that holds the electro-optical panel, a first temperature detecting element that is disposed on the electro-optical panel and detects the temperature of the electro-optical panel, and a second temperature detecting element that is disposed on the holder and detects the temperature of the holder. When four quadrants are defined by an X axis line passing through a center of the display region and a Y axis line passing through the center of the display region and orthogonal to the X axis line, the first temperature detecting element and the second temperature detecting element are disposed in the same quadrant.