An optical module comprising: at least three lens elements, wherein the lens elements collectively set a numerical aperture NA, a field height FH, and a system effective focal length EFLsys for directing the light rays between first and second planes, wherein NA, FH, and EFLsys satisfy 0<NA<0.25 and 0<FH<(0.4).Math.(EFLsys); wherein first and second adjacent lens elements having effective focal lengths EFL1 and EFL2, respectively, satisfies (1.5).Math.(EFLsys)<EFL1<3.Math.(EFLsys) and (1.5).Math.(EFLsys)<EFL2<3.Math.(EFLsys); wherein an air-distance between the first and second lens elements A.sub.12 satisfies 0<A.sub.12<EFLsys; wherein a third lens element adjacent the second lens elements opposite the first lens element and having an effective focal length EFL3 satisfies (−20).Math.EFLsys<EFL3<(−1).Math.EFLsys; and wherein an air-distance between the second and third lens elements A.sub.23 satisfies 0<A.sub.23<EFLsys.

A multichannel tunable lens system may include a review channel with a fluidic focusing device, which can adjust the focus of the channel rapidly to mitigate environmental vibrations. The review channel may generate high resolution images with reduced blur caused by vibrations or air turbulence while increasing the operating speed of the system. The review channel may include a telescope objective and eyepiece with telecentricity to generate a real image of the pupil in the fluidic focusing device. The system may also include an inspection channel to generate lower resolution images in parallel and a focus channel to determine contour information.

The invention relates to an attachment device for at least one objective lens and/or at least one eyepiece of a long-range optical device, in particular in the form of a riflescope, a telescope or a binocular, wherein the attachment device comprises at least one window, which is transparent at least in a visible spectral range, as well as at least one electrical heating device for the window.

An optical mirror assembly includes a crystalline face sheet and a carbon fiber sandwich. The crystalline face sheet has a first surface configured to reflect light and a second surface coupled to the carbon fiber sandwich by a layer of epoxy. The carbon fiber sandwich is configured to structurally support the crystalline face sheet. The carbon fiber sandwich includes a first carbon fiber layer, a second carbon fiber layer and a substrate positioned between the first carbon fiber layer and the second carbon fiber layer.

Embodiments of the present disclosure generally relate to methods of forming a substrate having a target thickness distribution at one or more eyepiece areas across a substrate. The substrate includes eyepiece areas corresponding to areas where optical device eyepieces are to be formed on the substrate. Each eyepiece area includes a target thickness distribution. A base substrate thickness distribution of a base substrate is measured such that a target thickness change can be determined. The methods described herein are utilized along with the target thickness change to form a substrate with the target thickness distribution.

The invention relates to an optical viewing system and a method of aligning an eyepiece image and an image of a camera that is part of an optical viewing system, which enables both the observation of an optical image with one eye and the capturing of the optical image with the camera. The optical viewing system comprises an optical device, an eyepiece with field diaphragm, a beam splitter, and a camera with image capturing level. According to the method, an image mask is adjusted to the eyepiece image for the camera image of the camera as follows: The eyepiece is illuminated from its side facing away from the optical device, and light passes through the eyepiece to the beam splitter so that the light is partially reflected from the first semi-reflective surface to the second semi-reflective surface and from the second semi-reflective surface to the camera, resulting in the camera capturing an image of the field diaphragm of the eyepiece as a light spot on the image capturing level. The position of the center point of the light spot on the image capturing level is determined. The image mask is aligned based on the position of the center point of the light spot on the image capturing level.

A lens including ejector pin marks formed at contacting portions with ejector pins used in molding, with a first side including the ejector pin marks and a second side not including the ejector pin marks. The ejector pin marks are located outside of an optical effective diameter on the first side, and at least one of the ejector pin marks on the first side is located inside an optical effective diameter on the second side.

A display apparatus that can surely make an image reach an observer's pupil without imposing a burden on the observer. The apparatus includes: an eyepiece optical system; and an image display apparatus including an image forming apparatus and a transfer optical system. The eyepiece optical system and the image display apparatus are spatially separated from each other, the eyepiece optical system forms an image from the transfer optical system on a retina of an observer, the image display apparatus further includes a first position detection apparatus that detects a position of the eyepiece optical system, a second position detection apparatus that detects a position of a pupil of the observer. On the basis of detected positional information of the eyepiece optical system and the pupil, the transfer optical system is controlled such that the image incident from the image forming apparatus reaches the eyepiece optical system.

A display apparatus that can surely make an image reach an observer's pupil without imposing a burden on the observer. The apparatus includes: an eyepiece optical system; and an image display apparatus including an image forming apparatus and a transfer optical system. The eyepiece optical system and the image display apparatus are spatially separated from each other, the eyepiece optical system forms an image from the transfer optical system on a retina of an observer, the image display apparatus further includes a first position detection apparatus that detects a position of the eyepiece optical system, a second position detection apparatus that detects a position of a pupil of the observer. On the basis of detected positional information of the eyepiece optical system and the pupil, the transfer optical system is controlled such that the image incident from the image forming apparatus reaches the eyepiece optical system.

An observation optical system according to the present invention includes a Fresnel lens and a lens LP with a positive refractive power provided on a light incident side or a light emitting side of the Fresnel lens. A length in a direction of an optical axis from a surface vertex of a central annular section of the Fresnel lens to an end portion of the central annular section is defined as h0, and a length in the direction of the optical axis of a grating wall surface of a first annular section adjacent to the central annular section is defined as h1. The lengths h1 and h0 are set to appropriate values, respectively.