Abstract: The present invention relates to an improved collimator assembly that includes two separate optical paths. Each optical path passes through a corrector lens arrangement substantially centered and aligned with one of two eyepiece lens assemblies. Each corrector lens arrangement is constructed so as to selectively refract light passing through it, in such a manner so as to counteract and reduce the axial chromatic aberrations that occur in the eyepiece lens assemblies.

Abstract: A zoom lens, for use in a telescope at infra-red wavelengths or single wavelength visible light, provides a magnification which may be adjusted to either of two predetermined values. The lens comprises a pair (14) of similar elements (15, 16) fixed relative to one another and each having an aspheric convex surface with the aspheric surfaces of the pair of elements outermost. The pair of elements (14) is located between the two image planes formed in the telescope and is movable between two conjugate positions.

Abstract: In order to eliminate the influence of temperature on the focus of an IR optical imaging system, radiation from an auxiliary heat source is deflected through the IR optical imaging system such that said radiation impinges on an autocollimating reflector from where it is reflected back into said IR optical imaging system and then impinges on detector elements which are arranged in a detector image plane. Electrical signals generated by the affected detectors are analyzed, digitized, and then compared in a computer whose output signals control a motor for adjusting the axial position of at least one of the optical lens elements of the IR system such that the autocollimating condition between the auxiliary heat source and its image in the detector plane is maintained at all times.

Abstract: An optical recording system including a read/write optical assembly including an objective lens for reading or writing from an optical medium including a solid immersion lens disposed between the objective lens and having a surface closely spaced from the recording medium.

Abstract: A lithography system employing a solid immersion lens having a spherical surface to enhance its resolution is disclosed.

Abstract: An optical element includes a base layer of a first material selected from the group consisting of gallium arsenide, gallium phosphide, cadmium telluride, mercury cadmium telluride, zinc sulfide and zinc selenide, and a coating layer of the selected base layer material. The coating layer has a predetermined degree of intrinsic compressive stress to protect the base layer.

Abstract: This invention is concerned with a thermal imaging optical system finding utility as an individual weapon sight. The system comprises an infra-red objective lens including a chopper blade together with front and back elements with an adjustable element therebetween. Infra-red radiation is received by the objective lens which also incorporates an internal substantially collimated plane polarized visible light source which illuminates a liquid crystal. The path of the infra-red and visible light which is directed to the liquid crystal cell, is repeatedly interrupted by the chopper blade. Changes in the liquid crystal cell due to the infra-red radiation transmitted by the objective lens are caused to modulate the plane polarized visible light transmitted through the liquid crystal cell to generate a visible image. This image passes through a relay inverting system and is detected by a visible light detector and viewed through an eyepiece.

Abstract: An optical element (12) has aspherical (14) and binary grating (16) optical surfaces. In the preferred embodiment, the optical element (12) is a positive meniscus optical element made of germanium having a useful spectral bandpass in the infrared wavelength region. A telescope (100) includes a first positive meniscus optical element (102), having a convex aspherical surface (104) and a concave binary grating surface (106). A first negative meniscus optical element (107) having a concave binary grating surface (108) and a concave aspherical surface (110) is employed. Next is a positive power lens (112), followed by a second negative meniscus lens (118). In the preferred embodiment, the first negative meniscus optical element (107) and the positive power lens (112) are affixed to a common housing (124), which is removable from the telescope system. Removal of the housing (124) converts the telescope (100) system from a wide-field-of-view telescope (100) to a narrow-field-of-view telescope (40).