A projection system includes a first optical system and a second optical system disposed on an enlargement side of the first optical system. The first optical system includes a first lens group having positive power, a second lens group disposed on the enlargement side of the first lens group and having negative power, and an optical path deflector disposed between the first lens group and the second lens group. The second optical system includes a reflection member having a concave reflection surface. The second lens group includes three aspherical lenses. Conditional Expression (1) below is satisfied,

0.25<|F|×FNO/Ymax<0.5  (1)

where F represents the focal length of the entirety of the projection system, FNO represents the F number of the projection system, and Ymax represents a maximum image height in a reduction-side conjugate plane.

A directivity backlight display device with reflector curvature assisted diffuser includes a light source module, a reflective narrow-angle diffuser, a concave reflector, and a backlit type display panel. The light source module projects a light. The reflective narrow-angle diffuser includes a concave surface or a flat surface served as a reflecting surface. The reflecting surface is provided with a plurality of micro curved mirrors laid out in an array. The light is reflected and diffused by the reflective narrow-angle diffuser and the concave reflector to provide a uniform directional light beam. A backlit type display panel is deployed to display an image. The uniform directional light beam penetrates the backlit type display panel to provide a directional image light beam, and then projects the directional image light beam to a projection area. With this arrangement, a reflective narrow-angle diffuser with a low concave curvature is deployed to achieve a high-directivity image projection.

An optical module in the present disclosure includes a first image display panel including a first display part and a first coupling part, a second image display panel including a second display part and a second coupling part, a third image display panel including a third display part and a third coupling part, and a cross dichroic prism configured to synthesize first, second, and third image light. The cross dichroic prism has a cross axis at which a two of photosynthesis surfaces cross each other. The first, second, and third image display panel are respectively bonded to different surfaces of the cross dichroic prism in a state where a long side of each of the first, second, and third display part extends along the cross axis and where the first, second, and third coupling part are each positioned on an outer side of the cross dichroic prism.

An optical module in the present disclosure includes a first image display panel including a first display part and a first coupling part, a second image display panel including a second display part and a second coupling part, a third image display panel including a third display part and a third coupling part, and a cross dichroic prism configured to synthesize first, second, and third image light. The cross dichroic prism has a cross axis at which a two of photosynthesis surfaces cross each other. The first, second, and third image display panel are respectively bonded to different surfaces of the cross dichroic prism in a state where a long side of each of the first, second, and third display part extends along the cross axis and where the first, second, and third coupling part are each positioned on an outer side of the cross dichroic prism.

A projection system includes a first and second optical system including an optical element. The optical element has a first transmissive surface, a reflection surface, and a second transmissive surface. The second transmissive surface has a convex shape an aspheric shape. An effective light ray range of the second transmissive surface has a first end close to an optical axis of the reflection surface in a first axis direction along a first axis perpendicular to the optical axis and a second end far from the optical axis. A first radius of curvature at the first end is greater than a second radius of curvature at the second end, and a first center of curvature of the first radius of curvature is farther than a second center of curvature of the second radius of curvature from the first end.

A projection system includes a first and second optical system including an optical element. The optical element has a first transmissive surface, a reflection surface, and a second transmissive surface. The second transmissive surface has a convex shape an aspheric shape. An effective light ray range of the second transmissive surface has a first end close to an optical axis of the reflection surface in a first axis direction along a first axis perpendicular to the optical axis and a second end far from the optical axis. A first radius of curvature at the first end is greater than a second radius of curvature at the second end, and a first center of curvature of the first radius of curvature is farther than a second center of curvature of the second radius of curvature from the first end.

Disclosed is an ultra-short focus projecting optical system, which includes a display unit, a first lens group having a positive focus power, a second lens group having a positive focus power, a third lens group having a negative focus power, and an aspherical reflector arranged sequentially along a projection direction. The first lens group includes a first lens, a second lens and a diaphragm arranged sequentially along the projection direction. The first lens is a glass aspherical lens, the second lens is a glass spherical lens, and the first lens and the second lens are bent toward the diaphragm from their respective centers to their respective peripheries. The ultra-short focus projecting optical system and a projection device provided by this application can realize a large aperture and high resolution.

The head-up display apparatus includes a display-light emitting unit having a second inclination angle around the axis parallel to the vertical direction so that the first direction side thereof is closer to the user than the second direction side thereof is, and being configured to emit display light forming a rectangular image corresponding to the rectangular virtual image. The head-up display apparatus includes a reflecting mirror having a third inclination angle around the axis parallel to the vertical direction so that the first direction side thereof is closer to the user than the second direction side thereof is, and being configured to reflect the display light and emit reflected light to the virtual-image display unit.

A system and method for the projection of virtual 3-D images onto a surface with perspective shifting viewing capability including: a source of data for at least two different paired left-right view sets of one subject, an image reflecting surface, and a projector capable of simultaneously projecting pairs of left-right view sets, and capable of changing projected left-right view sets of images from a first set to a second set to create a stereopsis effect in which content of a complete projected image appears to move in perspective.

A system and method for the projection of virtual 3-D images onto a surface with perspective shifting viewing capability including: a source of data for at least two different paired left-right view sets of one subject, an image reflecting surface, and a projector capable of simultaneously projecting pairs of left-right view sets, and capable of changing projected left-right view sets of images from a first set to a second set to create a stereopsis effect in which content of a complete projected image appears to move in perspective.