A cooling device of a projection display apparatus includes a first heat receiving unit including an opening that is rectangular. The first heat receiving unit includes a flow path part that forms the opening. An image display element of the projection display apparatus includes a first front face located in front of a reflective image display, a second front face parallel to the first front face and located behind and outside the first front face, and a first side face located between the first front face and the second front face. The first front face is inserted into the opening, and the flow path part is in contact with the first side face and the second front face via a heat conductive member. The flow path part includes a front face that is flush with or in front of the first front face of the image display element.

A cooling device of a projection display apparatus includes a first heat receiving unit including an opening that is rectangular. The first heat receiving unit includes a flow path part that forms the opening. An image display element of the projection display apparatus includes a first front face located in front of a reflective image display, a second front face parallel to the first front face and located behind and outside the first front face, and a first side face located between the first front face and the second front face. The first front face is inserted into the opening, and the flow path part is in contact with the first side face and the second front face via a heat conductive member. The flow path part includes a front face that is flush with or in front of the first front face of the image display element.

A prism includes a first intermediate imaging position at which a component in a first direction of the light flux is imaged and a second intermediate imaging position at which a component in a second direction orthogonal to the first direction of the light flux is imaged, different from the first intermediate imaging position. At least one of the first intermediate imaging position and the second intermediate imaging position lying within a first range from the second surface between the first surface and the second surface or lying within a second range from the second surface between the second surface and the third surface. The first range has a length less than one-half of an optical path length from the first surface to the second surface, and the second range has a length less than one-half of the optical path length from the second surface to the third surface.

A prism includes a first intermediate imaging position at which a component in a first direction of the light flux is imaged and a second intermediate imaging position at which a component in a second direction orthogonal to the first direction of the light flux is imaged, different from the first intermediate imaging position. At least one of the first intermediate imaging position and the second intermediate imaging position lying within a first range from the second surface between the first surface and the second surface or lying within a second range from the second surface between the second surface and the third surface. The first range has a length less than one-half of an optical path length from the first surface to the second surface, and the second range has a length less than one-half of the optical path length from the second surface to the third surface.

An optical display assembly includes an optical-mechanical module, an optical transmission element, and a light path altering element. The optical-mechanical module is configured to cast light. The optical transmission element is configured to receive the light on a first surface thereof and reflect the light in an interior between the first surface and a second surface thereof. The first surface is at a first angle with respect to a light-emitting surface of the optical-mechanical module. The light path altering element is disposed between the optical transmission element and the optical-mechanical module and configured to receive the light and cast the light onto the first surface. The light exits the first surface. A distance between the third surface and a center of a position at which the light exits the first surface is within a predetermined range.

A head-mounted device (HMD) contains a display, an optics block, a redirection structure, and an eye tracking system. The display is configured to emit image light and provide it to an eye of a user. The optics block is configured to direct the emitted light in order to allow it to reach the eye. The eye tracking system contains a camera, an illumination source, and a controller. The camera is configured to capture image data using infrared light reflected from the eye. The controller is configured to use this image data to determine eye tracking information. The illumination source is configured to illuminate the eye with infrared light for the purpose of taking eye tracking measurements. The redirection structure is configured to direct infrared light reflected from the eye to the eye tracking system. In multiple embodiments, redirection structures may comprise prism arrays, lenses, liquid crystal layers, or grating structures.

A vehicular frameless interior rearview mirror assembly includes a mirror head and a mounting portion. The mirror head includes a mirror reflective element and a mirror casing. The mirror reflective element includes a glass substrate having a planar front side and a planar rear side. No portion of the mirror casing overlaps the planar front side of the glass substrate of the mirror reflective element. A camera is disposed within the mirror casing. With the mounting portion of the mirror assembly mounted at an in-cabin side of a windshield of a vehicle, the camera views a driver of the vehicle, and when the mirror head is moved by the driver of the vehicle to adjust the rearward view provided by the mirror reflective element to the driver, the camera moves in tandem with movement of the mirror head. The camera is part of a driver monitoring system of the vehicle.

A vehicular frameless interior rearview mirror assembly includes a mirror head and a mounting portion. The mirror head includes a mirror reflective element and a mirror casing. The mirror reflective element includes a glass substrate having a planar front side and a planar rear side. No portion of the mirror casing overlaps the planar front side of the glass substrate of the mirror reflective element. A camera is disposed within the mirror casing. With the mounting portion of the mirror assembly mounted at an in-cabin side of a windshield of a vehicle, the camera views a driver of the vehicle, and when the mirror head is moved by the driver of the vehicle to adjust the rearward view provided by the mirror reflective element to the driver, the camera moves in tandem with movement of the mirror head. The camera is part of a driver monitoring system of the vehicle.

Disclosed are an optical path changing unit and a lens assembly comprising same. The optical path changing unit comprises: a base; a prism unit a part of which is connected to the base and the other part of which is arranged to be movable within the base; and first to third optical image stabilizing (OIS) drive units which change the prism unit into a tiltable position.

A purpose of the present invention is to realize a prism sheet in which an outer shape is circular and has a concentric prism array. The present invention includes the structure: A prism sheet has a circular outer shape and a concentric prism array on one surface, in which groove is formed in radial direction from a center of the concentric prism array so as to cross the concentric prism array. The air entrained in the prism array during manufacturing is exhausted through the groove.