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.

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.

A vehicular camera for a vehicular vision system includes a PCB having an imager disposed thereat, a lens barrel accommodating a lens, and a lens barrel support structure that protrudes from the PCB and at least partially circumscribes the imager. The lens barrel has an outer surface that extends between the ends of the lens barrel. The outer surface of the lens barrel is adhesively bonded to an inner surface of the lens barrel support structure via adhesive. The outer surface of the lens barrel radially opposes the inner surface of the lens barrel support structure where the adhesive is disposed. With the adhesive in its uncured state and contacting the opposed surfaces, the imager is optically aligned with the lens accommodated at the lens barrel. With the imager optically aligned with the lens, the adhesive is cured to adhesively attach the lens barrel at the lens barrel support structure.

A light detection device includes a Fabry-Perot interference filter, a light detector, a spacer that has a placement surface on which a portion outside a light transmission region in a bottom surface of the interference filter is placed, and an adhesive member that adheres the interference filter and the spacer to each other. Elastic modulus of the adhesive member is smaller than elastic modulus of the spacer. At least a part of a lateral surface of the interference filter is located on the placement surface such that a part of the placement surface of the spacer is disposed outside the lateral surface. The adhesive member is disposed in a corner portion formed by the lateral surface of the interference filter and the part of the placement surface of the spacer and contacts each of the lateral surface and the part of the placement surface.

Provided is a head-up display including a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, a backlight that emits light toward the Fresnel lens, a light-transmissive member between the backlight and the Fresnel lens, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space, where a length of the liquid-crystal panel in a longitudinal direction of the head-up display is longer than a length of the light-transmissive member in the longitudinal direction.

A wavelength conversion module and a projector including the wavelength conversion module are provided. The wavelength conversion module includes a substrate and a wavelength conversion layer. The substrate has a first surface and a second surface opposite to each other. The substrate includes a plurality of turbulent portions, and the turbulent portions are recessed in at least one of the first surface and the second surface. The wavelength conversion layer is disposed on the first surface of the substrate, and a distribution area of the turbulent portions accounts for more than 60% of an exposure area of the substrate. The wavelength conversion module and the projector provided by the disclosure exhibit favorable heat dissipation efficiency.

A holographic sight comprises a unitary optical component carrier having a plurality of receptacles for receiving optical components. A collimating optic abuts a surface of a first receptacle. A mirror abuts a surface of a second receptacle. A collar is positioned in a third receptacle and a laser diode is positioned within the collar. A first portion of the collar is affixed relative to a first portion of the third receptacle and a second portion of the collar is free to expand and contract relative to the third receptacle. The laser diode is affixed to the collar proximate the second portion and is free to move relative to the third receptacle with expansion and contraction of the second portion. The laser diode, the mirror, and the collimating optic are positioned relative to each other to create an optical path.

A virtual reality and augmented reality system configured for meditation applications including a headset comprising an adjustable strap and a display. The headset further includes heating and cooling elements to provide an immersive virtual reality environment to a wearer. The virtual reality system is operable to determine the physiological condition of the wearer and adjust the virtual reality environment based on the physiological condition of the wearer.

A vibrator includes an electromechanical transducer which is a piezoelectric ceramic made of sodium-potassium niobate metal oxides and whose temperature characteristics of a relative permittivity is 500 [ppm/° C.] or less in absolute value in a temperature range from −40° C. to 170° C., wherein excitation of the electromechanical transducer produces a vibration wave. Another vibrator includes an electromechanical transducer which is a piezoelectric ceramic made of sodium-potassium niobate metal oxides and whose temperature characteristics of a relative permittivity is 390 [ppm/° C.] or less in absolute value in a temperature range from 0° C. to 60° C., wherein excitation of the electromechanical transducer produces a vibration wave.

An optical element includes a hologram layer, a resin substrate to which the hologram layer is adhered, and a holder portion that supports the resin substrate and has a thermal expansion coefficient smaller than that of the resin substrate. One of the holder portion and the resin substrate includes a contact surface along an axis extending in a plate thickness direction of the resin substrate, and the other of the holder portion and the resin substrate includes a pressing surface that presses the contact surface.