A projection apparatus includes a light source, a light modulation portion, a first mirror, a second mirror, a third mirror, a fourth mirror, and a projection optical system. The light source performs irradiation with light. The light modulation portion modulates the light from the light source. The first mirror, the second mirror, the third mirror, and the fourth mirror reflect an optical image modulated by the light modulation portion. The projection optical system projects the optical image reflected by the first mirror, the second mirror, the third mirror, and the fourth mirror to a projection surface of a projection target object. The first mirror, the second mirror, the third mirror, and the fourth mirror are arranged between the light modulation portion and the projection optical system.

A lens retaining device includes a first shifter and a second shifter. The first shifter holds a lens and moves in a first direction perpendicular to an optical axis direction of the lens. The second shifter supports the first shifter and moves in a second direction perpendicular to the optical axis direction and the first direction. The first shifter includes a first main body moves in the first direction, a lens retainer that is provided on the first main body and retains the lens, and a first drive portion that moves the first main body. The lens retainer is integrally formed with the first main body.

In described examples, a geometric progression of structured light elements is iteratively projected for display on a projection screen surface. The displayed progression is for determining a three-dimensional characterization of the projection screen surface. Points of the three-dimensional characterization of a projection screen surface are respaced in accordance with a spacing grid and an indication of an observer position. A compensated depth for each of the respaced points is determined in response to the three-dimensional characterization of the projection screen surface. A compensated image can be projected on the projection screen surface in response to the respaced points and respective compensated depths.

A projection lens has a first rotary tube, a first fixed tube at which the first rotary tube is rotatably mounted, a first protrusion portion that is provided at the first rotary tube and that protrudes from the first rotary tube, and a first abutment surface that is provided at the first fixed tube and that abuts upon the first protrusion portion. The projection lens includes a first engaging portion at which the first protrusion portion and the first abutment surface include first engaging portions that face each other in a direction of a first incidence-side optical axis and a first pressing portion that presses the first protrusion portion against the first abutment surface.

A first holding barrel, a first mirror bending a first optical axis of the first holding barrel at 90°, a second holding barrel, a second mirror bending a second optical axis of the second holding barrel at 90°, and a third holding barrel are disposed on an optical axis from a screen side to an image forming panel. A first connection member connects the first holding barrel including the first mirror to the second holding barrel to be rotationally movable in increments of 90°. A second connection member connects the second holding barrel and the second mirror to the third holding barrel to be rotationally movable in increments of 90°. An orientation of a display image of the image forming panel is changed based on rotational movement states of an optical axis of a first sensor and an optical axis of a second sensor to make an orientation of a projection image on the screen match an original image.

An optical device including a holder and a light transmissive plate is provided. The holder includes a first frame and a second frame connected to each other, and the first frame is located inside the second frame. A light transmissive plate is disposed inside the first frame and has a surface. The first frame has at least one inner surface and includes at least one surface supporting part, and the surface supporting part extends along a direction from the inner surface of the first frame to the center of the first frame, and the surface of the light transmissive plate is at least partially supported by the surface supporting part of the first frame. The surface supporting part is non-continuously distributed along the inner surface of the first frame. The disclosure further provides a projector including the optical device.

The projection device includes a display element that displays an image, a projection optical system that forms an intermediate image of the image within an air space and projects the intermediate image to form a projected image, and a light shielding member that is disposed within the air space. The light shielding member includes a light shielding region which is positioned outside optical paths of all effective luminous fluxes emitted from the display element and used to form the projected image. The projection device satisfies a predetermined conditional expression.

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.

Provided are a lens adjusting device and a projection apparatus. The device includes a first adjusting support including a lens support, a first guide post and a second guide post; and a second adjusting support including a moving support, a first limit slot, and a first boss. The first guide post is fixedly clamped in the first limit slot, the second guide post being connected to the first boss, and the lens support being supported by and slidably connected to the first guide post and second guide post, such that the lens support is slidable relative to the second adjusting support along the first direction. The lens support is configured to adjust a position of the second guide post relative to the first boss prior to the second guide post and the first boss being fastened to each other to parallel the second guide post and the first guide post.

An illumination system including multiple light sources, a first light combining module, a second light combining module, and a converging lens is provided. The light sources respectively provide multiple beams with the same wavelength range. The first light combining module is disposed on a transmission path of a portion of the beams. The second light combining module is disposed on a transmission path of another portion of the beams to combine the beams into an exciting beam. The converging lens is disposed on a transmission path of the exciting beam.