An optical unit includes an input portion configured to have measurement light having a wavelength extending from an ultraviolet region to a visible region input thereto, an optical system configured to condense the measurement light in a state where a chromatic aberration is caused to occur, and an opening portion configured not to image light having a wavelength in the visible region and to image light having a wavelength in the ultraviolet region of the measurement light having a chromatic aberration having occurred therein.

An optical imaging system having a free-form surface includes an image source for generating image light, a lens assembly for reflecting the image light incident thereon, a first reflective surface, a second reflective surface, and a beam splitter that are disposed opposite to each other. The present disclosure allows the image light to pass through the lens assembly twice, reduces the weight of the optical system, and makes the system structure more compact, thus providing an optical imaging system featuring low distortion, high image quality, and a compact structure. A reflective surface is disposed between the image source and the lens assembly, so that the distance between the image source and the lens assembly can be reduced. The second reflective surface is designed as a free-form surface and a first lens and a second lens are aspheric lenses.

The present disclosure provides an optical system that includes a prism having an incident surface, an exit surface, and one or more reflecting surfaces. The optical system includes a first scanning element configured to scan a light that enters and has a plurality of wavelengths in a first direction, and reflect the light in a direction of the incident surface of the prism. The optical system includes a second scanning element configured to scan in a second direction the light that exits from the exit surface of the prism, the second direction being orthogonal to the first direction. The incident surface of the prism has a concave shape with respect to the first scanning element.

An optical module according to the present disclosure includes: a first display panel that emits a first image light, a first virtual image optical system that forms a first exit pupil of the first image light, and a control unit corrects a video image signal to a first correction video signal based on distortion generated in the first optical system, an aspect ratio of the video image signal being smaller than an aspect ratio of the first display panel, wherein the control unit causes the first display panel to emit the first image light from the first display panel based on the first correction video image signal.

A head-up display projects an image on a windshield to allow a viewer to visually observe a virtual image. The head-up display includes a display device, a relay optical system, and a projection optical system. The display device displays an image. The relay optical system provides the image displayed by the display device as an intermediate image. The projection optical system reflects the intermediate image provided by the relay optical system to project the intermediate image on the windshield.

A lens system includes a curved primary mirror and an aspheric secondary mirror. The aspheric secondary mirror has a diameter smaller than that of the primary mirror and shares an optical axis with the primary mirror. The aspheric secondary mirror and the primary mirror are rotationally symmetric with respect to the optical axis. A support member, which may be transparent over an operating wavelength of the lens system, is disposed on the aspheric secondary mirror.

An optical system includes, in order from a reduction conjugate side to an enlargement conjugate side, a refractive optical unit having a positive refractive power, and a mirror optical unit that includes a mirror element having a positive refractive power and a mirror element having a negative refractive power and reforms an intermediate image formed by the refractive optical unit. A predetermined condition is satisfied.

A virtual image display apparatus according to the present disclosure includes a first display module, a second display module, and a coupling portion having an adjustable structure. The adjustable structure adjusts the first display module with respect to the second display module at least a relative rotational position and relative positions in longitudinal and depth directions.

An image projection device projects an image to a projection surface, and includes an image forming element, a refractive optical unit, and a reflective optical unit. The image forming element forms an image to be projected to the projection surface based on an image signal. The refractive optical unit has a refractive optical system including a plurality of lenses guiding light of the image toward the projection surface, the image being formed by the image forming element. The reflective optical unit includes a reflective optical system having a first mirror reflecting the light guided by the refractive optical system and a second mirror reflecting the light reflected by the first mirror toward the projection surface; and a blocking section including a blocking surface disposed at a position of blocking part of light generated in the refractive optical unit and passing through between the first mirror and the second mirror.

A catadioptric photographic lens include; a first reflecting mirror, a second reflecting mirror, and a lens group, arranged in order from an object so that light reflected by the first reflecting mirror is reflected by the second reflecting mirror before passing through the lens group and forms an image of the object upon a predetermined image plane wherein; the first and the second reflecting mirror are off-center on the reference plane; reflection surfaces of the first and the second reflecting mirror are rotationally asymmetric aspheric surfaces; the reflection surface of the first reflecting mirror is concave toward the object on the reference plane and on the first orthogonal plane; and the surface closest toward the second reflecting mirror in the lens group having two lenses made from the same optical material as one another is a rotationally asymmetric aspheric surface.