Integrated telescopes are described that are stable and compact, and include optics pieces that are susceptible to stray light. One example telescope includes an optics piece formed of a transparent optical material and two surfaces with each surface including a reflector surface and a baffle. The baffles may be formed in a groove in one of the surfaces of the optics piece. The baffle may have an index of refraction that is approximately the same as an index of refraction of the optics piece. The baffle may include a blackened epoxy, a carbon black material, or a powdered black spinel. The integrated telescope may include a short-wave infrared image sensor fixed in position relative to the optics piece.

A display device includes a light source, a spatial light modulator (SLM), and an optical assembly that includes a first reflective surface and a second reflective surface that is opposite to the first reflective surface. The light source is configured to provide illumination light. The optical assembly is configured to receive the illumination light. At least a first portion of the illumination light received by the optical assembly is transmitted through the first reflective surface toward the second reflective surface, is reflected by the second reflective surface toward the first reflective surface, is reflected by the first reflective surface toward the second reflective surface, and is transmitted through the second reflective surface. The SLM is configured to receive and modulate the portion of the illumination light transmitted through the optical assembly, and to output the modulated light. A method performed by the display device is also disclosed.

A display device includes a light source, a spatial light modulator, and an optical assembly. The light source is configured to provide illumination light and the spatial light modulator is positioned to receive the illumination light. The optical assembly includes a first reflective surface with an aperture and a second reflective surface that is opposite to the first reflective surface. The optical assembly is positioned relative to the light source so that at least a first portion of the illumination light received by the optical assembly is reflected by the second reflective surface toward the first reflective surface, is reflected by the first reflective surface toward the second reflective surface, and is transmitted through the second reflective surface. A method performed by the display device is also disclosed.

A display device includes a light source, a spatial light modulator, and an optical assembly. The light source is configured to provide illumination light and the spatial light modulator positioned to receive the illumination light. The optical assembly includes an optical element and a curved reflector that is distinct and separate from the optical element. The curved reflector is disposed relative to the light source so that at least a portion of the illumination light is reflected by the curved reflector toward the optical element, is reflected by the optical element toward the curved reflector, and is transmitted through the curved reflector. A method performed by the display device is also disclosed.

A display device includes a light source, a spatial light modulator, and an optical element. The optical element includes a reflective surface. The optical assembly is positioned relative to the light source so that at least a portion of the illumination light received by the optical element is reflected at the reflective surface back toward the light source. The spatial light modulator is positioned to receive at least a portion of the illumination light reflected by the reflective surface. A method performed by the display device is also disclosed.

An image pickup apparatus including an optical system and an image pickup element. The optical system includes a first refractive surface disposed closest to an object, a first reflection surface, and a second reflection surface. A light receiving surface of the image pickup element is disposed at only one side with respect to the optical axis and at a position closer to the optical axis than an intersection between a straight line connecting an intersection on the first refractive surface and an intersection on an imaginary extension surface of the second reflection surface and an imaginary extension surface of the light receiving surface. Expression 1.5L2/L16.5 is satisfied where L1 is an interval between the first reflection surface and the second reflection surface, and L2 is an interval between the first reflection surface and the light receiving surface.

A catadioptric optical system in sequence of ray tracing comprises a first mirrors group of Ritchey-Chrtien type hyperbolic mirrors with positive diopter including a concave primary mirror having a central through hole and a convex secondary mirror, a second corrector lens group with negative diopter positioned at the image-side of the first mirrors group including a first meniscus lens element having positive refractive power and a convex object-side surface, a second lens element having negative refractive power and biconcave surfaces, a third meniscus lens element having negative refractive power and a concave object-side surface, and a fourth lens element having positive refractive power and biconvex surfaces. The infinite conjugate beams of incident light within field of view pass through the catadioptric optical system to become a corrected beam having a small CRA angle.

Dual-band optical imaging systems and methods. One example of a dual-band optical system includes an all-reflective shared optical sub-system configured to receive combined optical radiation including first optical radiation having wavelengths in a first waveband and second optical radiation having wavelengths in a second, different waveband, and an optical element positioned to receive the combined optical radiation from the all-reflective shared optical sub-system and having a dichroic coating configured to transmit the first optical radiation and to reflect the second optical radiation, the optical element being configured to transmit the first optical radiation toward a first focal plane and to reflect and focus the second optical radiation to a second focal plane. The all-reflective shared optical sub-system and the optical element are each positioned symmetrically about a primary optical axis extending between the first focal plane and the second focal plane.

An optical system is capable observing a peripheral field away from a visual axis and includes a reflection mirror unit forming an image of an examined eye with two concave mirrors in an opposing arrangement facing each other at the examined eye side, this being the upstream side, of a first optical unit and a second optical unit. In the reflection unit there is a conjugate relationship between one focal point thereof and another focal point thereof. By forming an image of the examined eye using the reflection unit a distance can be secured between the examined eye and the optical system and a wide range of the examined eye can be observed.

An image capturing apparatus comprises an image sensor for capturing a subject image, a focus detection unit configured to, based on an image signal obtained by photoelectrically converting the subject image while performing a scan operation that causes a focus lens to move along an optical axis, calculate a focus evaluation value and detect a position of the focus lens at which the focus evaluation value is a maximum, and a calculation unit configured to, in a case where the imaging optical system includes a reflective optical system, calculate, based on information on the reflective optical system and information on an image forming position for each of a plurality of different spatial frequencies, a correction value for correcting a focus detection result of the focus detection unit.