A zoom optical system has, in order from an object: a first lens group G1 having positive refractive power; a second lens group G2 having negative refractive power; a third lens group G3 having positive refractive power; and a fourth lens group G4 having negative refractive power, wherein the mutual distance between the lens groups G1 to G4 change upon zooming, and one of the third lens group G3 and the fourth lens group G4 includes at least one diffractive optical element PF.

A lens form for a low parallax imaging device includes a plurality of imaging lens elements arranged to capture and image polygonal fields of view. The lens form includes a compression lens element group and a wide-angle lens element group.

Provided is a head-mounted display optical system (LS) having: an optical deflection element (M1); a first lens group (G1); a second lens group (G2); and an optical reflection element (M2). The head-mounted display optical system is configured such that light from a light source, which is reflected on a reflection surface (M2r) of the optical reflection element (M2) and reaches a drawing surface (I) assumed to be located on a retina when a user wears the head-mounted display, moves on the drawing surface (I) according to the change of a travelling direction of the light caused by the optical deflection element (M1), and an image is drawn on the drawing surface (I). The first lens group (G1) includes a free-shaped surface lens having a free-shaped surface which is rotationally asymmetrical with respect to a reference axis, and the reflection surface (M2r) of the optical reflection element (M2) is formed to be rotationally asymmetrical with respect to a reference axis.

A low-cost objective lens design uses only ZnS optical material, suitable for use with an uncooled infrared bolometer having a curved focal plane. Its objective lens field of view is at least 20.0 over a 1280720 pixel array with 0.0012 mm pitch. Lens chromatic aberrations are corrected over at least the 8-11 micron infrared wavelength band. The objective lens operates at a relatively fast F #/1.0 which is common in the art for bolometer applications.

A residual aberration controller arranged in the optical path of an image-forming light beam to create an aesthetic effect in an otherwise sharp image by selectively introducing residual aberrations into the wavefront of the image-forming light beam. The residual aberration controller is adjustable between a first configuration that provides either no substantial change or a relatively small aesthetic change to the otherwise sharp image and a second configuration that provides a substantial change to the sharp image to create the aesthetic effect. Aesthetic effects can include, to varying degrees, flare, bokeh, image softening, anamorphic and related effects that are desirable in certain imaging applications but that are difficult to produce in a quick and reversible manner. The residual aberration controller can be combined with almost any type of objective lens to achieve aesthetic imaging effects quickly, affordably and reversibly by a simple adjustment and without defocus.

An AR or VR display device. First and third input gratings receive light of a first color from first and second projectors, respectively, coupling the light into a first waveguide. Second and fourth input gratings receive light of a second color from the first and second projectors, respectively, coupling the light into a second waveguide. An output diffractive optical element couples light out of the waveguides towards a viewing position. The first and second projectors provide light to the input diffractive optical elements in directions that are at a first and second angle, respectively, to a waveguide normal vector. The output diffractive optical element couples light out of the waveguides in a first range of angles for light from the first projector and in a second range of angles for light from the second projector, the first range of angles and the second range of angles differing but partially overlapping.

An optical system includes an optical target for receiving an extended light source that emits a first light beam at a first radial distance from an optical axis and a second light beam at a second radial distance from the optical axis. The first light beam and the second light beam both have a first wavelength and a second wavelength. A first lens system is located between the extended light source and the optical target. A second lens system is located between the first lens system and the optical target. A first collection probability of the first light beam at the first wavelength, a second collection probability of the first light beam at the second wavelength, a third collection probability of the second light beam at the first wavelength, and a fourth collection probability of the second light beam at the second wavelength are the same within a criterion.

An AR or VR display device. First and third input gratings receive light of a first color from first and second projectors, respectively, coupling the light into a first waveguide.Second and fourth input gratings receive light of a second color from the first and second projectors, respectively, coupling the light into a second waveguide.An output diffractive optical element couples light out of the waveguides towards a viewing position.The first and second projectors provide light to the input diffractive optical elements in directions that are at a first and second angle, respectively, to a waveguide normal vector.The output diffractive optical element couples light out of the waveguides in a first range of angles for light from the first projector and in a second range of angles for light from the second projector, the first range of angles and the second range of angles differing but partially overlapping.

An achromatic lenses for a peep sight is to be mounted onto an archery bowstring. The achromatic lens is to be situated and retained in a lens cavity of the peep sight and includes various positive verifier or a negative clarifier glass lens joined by cement to a negative or positive flint lens, respectively. The peep sight has a peep sight body mounted to the bowstring with an internal hole therethrough with a front end, facing a front bow sight, and a rear end facing an archer's eye. An aperture with the lens cavity has a front end and a rear end and is adapted for locking engagement within the hole of the body. The aperture has a passage therethrough axially aligned with the threaded hole with a front end facing the front bow sight and a rear end to be facing the archer's eye. The lens cavity is in the passage suitably adjacent to the aperture's front end.