The present application relates to an off-axis two-mirror infrared imaging system including a primary reflecting mirror and a secondary reflecting mirror. The primary reflecting mirror is located on the incident light path of an incident infrared light beam and reflects the incident infrared light beam to form a first reflected light beam. The secondary reflecting mirror is located on the reflection light path of the primary reflecting mirror, and is used to reflect the first reflected light beam to form a second reflected light beam. The second reflected light beam reaches an image surface after passing through the incident infrared light beam. The reflective surfaces of the primary reflecting mirror and the secondary reflecting mirror are freeform surfaces. The secondary reflecting mirror and the image plane are respectively located on both sides of the incident infrared light beam.

There is provided a head-up display device which has a small size and of which the aberration is small and the range of an eye box in a vertical direction is wide. The head-up display device 10 includes a first optical system that includes at least one concave mirror arranged along an optical path of display light in order from an image display surface 1, and a second optical system that includes at least one concave mirror arranged along the optical path of the display light in order from the image display surface 1 side. An intermediate image is formed between the first and second optical systems on the optical path, and the first optical system includes a double reflection mirror that reflects the display light twice on the optical path.

A method for designing freeform surface imaging system comprises: constructing a series of coaxial spherical systems with different optical power (OP) distributions; tilting all optical elements of each coaxial spherical system by a series of angles to obtain a series of off-axis spherical systems; finding all unobscured off-axis spherical systems; and then specifying a system size or structural constraints, and finding a series of compact unobstructed off-axis spherical systems; constructing a series of freeform surface imaging systems based on the series of compact unobstructed off-axis spherical system, and correcting the OP of entire system; improving an image quality of each freeform surface imaging systems and finding an optimal tilt angle of an image surface; and automatically evaluating an image quality of each freeform surface imaging system based on an evaluation metric, and outputting the freeform surface imaging systems that meet a given requirements.

A light field volumetric device for displaying images or flows of fluctuating and stereoscopic 3D images. The device includes emitting means and a reflection system. The reflection system has first and second concave reflecting means. The first concave reflecting means comprises an aperture. An image generated by the device is perceivable by an observer, located at a distance with respect to the second concave reflecting means, when the observer looks towards the second concave reflecting means. A calculation unit is associated with the device and is configured to calculate the distance.

An apparatus includes an in-line reflective optical system configured to receive an input optical beam and provide an output optical beam. The in-line reflective optical system includes first and second powered mirrors aligned back-to-back. The first powered mirror is configured to reflect the input optical beam as a first intermediate beam. The in-line reflective optical system also includes first and second reflective surfaces respectively configured to reflect the first intermediate beam as a second intermediate beam and to reflect the second intermediate beam as a third intermediate beam. The second powered mirror is configured to reflect the third intermediate beam as the output optical beam. A spacing between the first and second reflective surfaces and the first and second powered mirrors is adjustable to control a focus of the output optical beam without introducing boresight error in the output optical beam.

A solar concentrator assembly (102) comprises a concave mirror (108) for collecting radiation that is collimated and has uniform distribution from a source and a convex mirror (110). The concave mirror (108) is configured to reflect the radiation to the convex mirror (110) and the convex mirror (110) is configured to reflect the radiation as a concentrated collimated beam in an emission direction that is angularly offset from the source. The concave mirror (108) and convex mirror (110) each have a focal length that varies along one axis such that the radiation collected by the concave mirror (108) is transmitted from the convex mirror (110) with uniform distribution.

A projection optical system includes an eyepiece optical system configured to refract and reflect a light emitted from an image forming unit for forming image information to display a virtual image, wherein the eyepiece optical system includes at least a concave lens, a folding mirror, and a concave mirror which are successively placed in order from the image forming unit including a liquid crystal display panel. The projection optical system configured as above is provided on a head-up display.

A method for designing freeform surface imaging system comprises: constructing a series of coaxial spherical systems with different optical power (OP) distributions; tilting all optical elements of each coaxial spherical system by a series of angles to obtain a series of off-axis spherical systems; finding all unobscured off-axis spherical systems; and then specifying a system size or structural constraints, and finding a series of compact unobstructed off-axis spherical systems; constructing a series of freeform surface imaging systems based on the series of compact unobstructed off-axis spherical system, and correcting the OP of entire system; improving an image quality of each freeform surface imaging systems and finding an optimal tilt angle of an image surface; and automatically evaluating an image quality of each freeform surface imaging system based on an evaluation metric, and outputting the freeform surface imaging systems that meet a given requirements.

A focusing device for focusing a laser beam in a target area. The focusing device includes a paraboloid mirror configured to widen the laser beam; an ellipsoid mirror or a hyperboloid mirror configured to focus the widened laser beam at a focal position within the target area; and a movement device. The movement device is configured to move the ellipsoid mirror or the hyperboloid mirror relative to the paraboloid mirror, or together with the paraboloid mirror, to change the focal position within the target area.

An inspection device according to the present disclosure includes a spheroidal mirror configured to reflect illumination light as convergent light, a plane mirror configured to reflect the illumination light incident as the convergent light and cause the reflected illumination light to be incident on an object of inspection as incident light, a projection optical system configured to focus reflected light of the incident light reflected by the object of inspection, and a detector configured to detect reflected light focused by the projection optical system, wherein an angle of incidence of an incident optical axis being an optical axis of the incident light on the object of inspection is greater than 6 [deg], an angle of reflection of a reflected optical axis being an optical axis of the reflected light on the object of inspection is greater than 6 [deg].