An extreme off-axis image projection system substantially compensates for image-quality-degrading aberrations typical to off-axis imaging systems. This is accomplished through the use of a free-form mirror in conjunction with both spherical and aspherical refractive elements and an off-axis placement of the input image source. In some embodiments, the off-axis image projection system contains a free-form mirror and a projection lens system with multiple lenses. The projection system projects light from an image source onto a surface (aka, projection surface). The projection surface is both close to the projector (in z) and extends away from the projector (in x and y).

An extreme off-axis image projection system substantially compensates for image-quality-degrading aberrations typical to off-axis imaging systems. This is accomplished through the use of a free-form mirror in conjunction with both spherical and aspherical refractive elements and an off-axis placement of the input image source. In some embodiments, the off-axis image projection system contains a free-form mirror and a projection lens system with multiple lenses. The projection system projects light from an image source onto a surface (aka, projection surface). The projection surface is both close to the projector (in z) and extends away from the projector (in x and y).

The present disclosure relates to the technical field of digital projection display, and discloses a projection method and a projection apparatus. The method includes: acquiring a target object image; identifying attribute information of a target object based on the target object image; acquiring preset projection content based on the attribute information of the target object; acquiring a projection path; and projecting a projection screen based on the preset projection content and controlling the projection screen to move along the projection path. In this way, the projection is more flexible and more pertinent.

The present disclosure relates to the technical field of digital projection display, and discloses a projection method and a projection apparatus. The method includes: acquiring a target object image; identifying attribute information of a target object based on the target object image; acquiring preset projection content based on the attribute information of the target object; acquiring a projection path; and projecting a projection screen based on the preset projection content and controlling the projection screen to move along the projection path. In this way, the projection is more flexible and more pertinent.

A projection system includes a first optical system including a plurality of lenses and a deflector, and a second optical system including an optical element having a concave reflection surface and disposed at the enlargement side of the first optical system. The deflector is disposed in one air gap of a plurality of air gaps provided between the lenses adjacent to each other in the first optical system, the air gap having the largest axial inter-surface distance in the first optical system. The first optical system includes a first section located at the reduction side of the deflector and a second section located at the enlargement side of the deflector. A first optical axis section of the first section and a second optical axis section of the second section intersect each other. The second section includes three or more lenses. The second section is shorter than the first section.

A projection system includes a first optical system including a plurality of lenses and a deflector, and a second optical system including an optical element having a concave reflection surface and disposed at the enlargement side of the first optical system. The deflector is disposed in one air gap of a plurality of air gaps provided between the lenses adjacent to each other in the first optical system, the air gap having the largest axial inter-surface distance in the first optical system. The first optical system includes a first section located at the reduction side of the deflector and a second section located at the enlargement side of the deflector. A first optical axis section of the first section and a second optical axis section of the second section intersect each other. The second section includes three or more lenses. The second section is shorter than the first section.

There is provided a head-up display device including: a display configured to emit a display light ray therefrom, a reflection member configured to pivot around a rotation axis and reflect the display light ray to project a display image; and a housing configured to accommodate the reflection member. The reflection member has a plurality of ribs protruding from a surface on an opposite side to a reflection surface which reflects the display light ray, and the plurality of ribs have a portion in which a height on an outer side in a rotational direction centered at the rotation axis is lower than that on an inner side in the rotational direction.

A head-up display includes a picture generation unit configured to project image light, a hexagonal optical reflection element arranged on a light path of the image light and including a hollow hexagonal cylinder, a concave mirror and an image display plate. The hollow hexagonal cylinder has a first sidewall, a second sidewall, a third sidewall, a fourth sidewall, a fifth sidewall and a sixth sidewall which are sequentially connected to form a closed hexagonal column. The second sidewall is transparent, and the first sidewall and the fifth sidewall opposite to the second sidewall are configured to reflect the image light. The concave mirror is disposed on the light path of the image light and configured to receive the image light reflected from the hollow hexagonal cylinder. The image display plate is configured to receive image light reflected from the concave mirror.

A head-up display includes a picture generation unit configured to project image light, a hexagonal optical reflection element arranged on a light path of the image light and including a hollow hexagonal cylinder, a concave mirror and an image display plate. The hollow hexagonal cylinder has a first sidewall, a second sidewall, a third sidewall, a fourth sidewall, a fifth sidewall and a sixth sidewall which are sequentially connected to form a closed hexagonal column. The second sidewall is transparent, and the first sidewall and the fifth sidewall opposite to the second sidewall are configured to reflect the image light. The concave mirror is disposed on the light path of the image light and configured to receive the image light reflected from the hollow hexagonal cylinder. The image display plate is configured to receive image light reflected from the concave mirror.

A parameter adjusting method is applied to a projector having an ambient light sensor, a database and a digital micromirror device. The parameter adjusting method includes analyzing a detection signal generated by the ambient light sensor to acquire an environmental light datum, comparing the environmental light datum with a lookup table of the database to compute at least one compensation parameter, and adjusting an amount of reflection light generated by the digital micromirror device in accordance with the at least one compensation parameter for controlling the projector to output a calibrated projection image in response to compensation of the environmental light datum.