A reflective microscope objective lens includes a concave mirror system that reflects incoming radiation, a convex mirror in optical communication with the concave mirror system, and a primary concave mirror in optical communication with the convex mirror. The concave mirror system includes a first concave mirror. The primary concave mirror focuses outgoing radiation onto a focal plane wherein the concave mirror system. Characteristically, the convex mirror and the primary concave mirror are arranged to direct light along a non-concentric path.

An optical system includes an incident part, a first reflective surface, a second reflective surface, a third reflective surface, and an exit part. The incident part is rotationally symmetric around a central axis. Incident light from the incident part intersects the central axis and enters the first reflective surface. Reflected light from the first reflective surface intersects the central axis and enters the second reflective surface. Reflected light from the second reflective surface enters the third reflective surface.

A freeform folded optical system that include two freeform prisms with optical power. At least one of the freeform prisms is configured to fold the optical axis twice. Thus, embodiments of the freeform folded optical system fold the optical axis three or four times. Folding the optical axis three or four times in the freeform prisms allows for long focal lengths required for telephoto lens applications without requiring additional lens elements between the prisms. In addition, the configuration of the freeform folded optical system provides reduced Z-axis height when compared to conventional folded lens systems with similar optical characteristics.

A head-up display is configured to project an image on a transparent reflection member to cause an observer to visually recognize a virtual image, and includes a display device configured to display the image, and a projection optical system configured to project the image displayed by the display device as the virtual image for the observer. The projection optical system is configured to form the image as an intermediate image, and includes a first optical element configured to condense light, a first lens configured to condense light, and a second optical element configured to diffuse light. The first optical element, the first lens, and the second optical element are disposed in this order along an optical path from the display device.

According to certain examples a spectrometer module for use in an imaging spectrometer includes a monolithic spectrometer body component made of an immersion material and including three mirrored surfaces configured to form a reflective triplet having an optical path immersed within the immersion material, the reflective triplet configured to receive incident optical radiation from an entrance face of the monolithic spectrometer body component and reflect the incident optical radiation along the optical path, and a dispersive element configured to receive and disperse the incident optical radiation reflected from the reflective triplet to provide dispersed optical radiation. The reflective triplet is configured to receive the dispersed optical radiation from the dispersive element and to reflect the dispersed optical radiation along the optical path to an exit face of the monolithic spectrometer body component.

An image display device according to an embodiment of the present technology includes a light source, an image generator, and a projection optical system. The image generator modulates a light beam emitted by the light source and generates image light. The projection optical system includes a first lens system, a first reflection optical system, a second lens system, and a second reflection optical system. The first lens system has a positive refractive power as a whole, and refracts the generated image light. The first reflection optical system includes two or more reflection surfaces, each reflection surface being a surface off which the image light refracted by the first lens system is reflected. The second lens system has a positive refractive power as a whole, and refracts the image light reflected off the first reflection optical system. The second reflection optical system includes a concave reflection surface off which the image light refracted by the second lens system is reflected to be directed to a projected-onto object onto which projection is performed.

A virtual image display apparatus includes a display device (image forming unit), a lens configured to refract imaging light from the display device, a first mirror member configured to reflect imaging light that passed through the lens, a second mirror member configured to reflect the imaging light reflected by the first mirror member, and a third mirror member of a transmissive type configured to reflect the imaging light reflected by the second mirror member toward a position of an exit pupil. The lens is asymmetric with respect to an optical axis in a first direction corresponding to an eccentric direction defined by the first mirror member and the second mirror member, and is symmetric, across the optical axis, with respect to a second direction orthogonal to the first direction.

A virtual image display apparatus includes a display device (image forming unit), a lens configured to refract imaging light from the display device, a first mirror member configured to reflect imaging light that passed through the lens, a second mirror member being a refractive reflective optical member configured to reflect the imaging light reflected by the first mirror member, and a third mirror member of a transmissive type configured to reflect the imaging light reflected by the second mirror member toward a position of an exit pupil. The refractive reflective optical member includes, across a refractive member, a refractive surface and a mirror surface. The lens and the refractive reflective optical member are integrated as a composite member.

Methods and systems for single beam scanning capable of imaging the surface of a spherical body of arbitrary radius of curvature are provided. The spherical imaging methods and systems utilize one or more off-axis parabolic (OAP) mirror to perform a geometrical transformation of the spherical surface to a flat rectilinear imaging coordinate grid such that the single scanning beam maintains a normal incidence across the curved field of view of the spherical body. The imaging methods and systems project the spherical surface to a Cartesian plane and then the remapped surface is rapidly imaged by raster-scanning an illumination beam in the rectangular coordinate such that the OAP mirror produces a rectilinear image of the target. The imaging of the spherical surface is accomplished while maintaining the target, illumination source, and detector in a stationary position. The imaging systems and methods may utilize a single source and a single detector, and may incorporate a THz illumination source. The beam scanning imaging systems and methods may be applied to corneal tissue imaging.

A freeform folded optical system that include two freeform prisms with optical power. At least one of the freeform prisms is configured to fold the optical axis twice. Thus, embodiments of the freeform folded optical system fold the optical axis three or four times. Folding the optical axis three or four times in the freeform prisms allows for long focal lengths required for telephoto lens applications without requiring additional lens elements between the prisms. In addition, the configuration of the freeform folded optical system provides reduced Z-axis height when compared to conventional folded lens systems with similar optical characteristics.