Abstract: An infrared microscope is disclosed which provides illumination for reflectance by the sample. This illumination follows a path through the objective toward the sample, and again, after reflection, through the objective toward the detector The reflectance illumination is directed toward the objective and sample by a fully reflective mirror, which injects approximately half of the interferometer beam into the microscope, and permits substantially all of the reflected beam to reach the detector.

Abstract: Cube-corner type retroreflective articles which retroreflect infrared light but do not substantially retroreflect visible light. The cube-corner elements comprise a polymeric matrix selected to be highly transmissive to infrared light but substantially opaque to visible light.

Abstract: An optical system (10) for producing dual fields of view simultaneously. The system (10) includes a first optical system (12) for producing a first field of view image and a second optical system (36) for producing a second field of view image where the angular displacement of the second field of view is different from that of the first field of view. A dichroic beamsplitter (22) is disposed in the present invention so as to reflect light from the first optical system (12). The dichroic beamsplitter (22) is also disposed so as to simultaneously transmit light from the second optical system (36). As a result, the reflected light (20) is primarily composed of light of a first wavelength band and the transmitted light is primarily composed of a second wavelength band. The light from the two different fields of view are then directed to a dual filter (32) which passes the first wavelength band in one portion and passes the second wavelength band in another portion.

Abstract: The disclosure relates to optical devices enabling daytime vision and night vision of an external scene with, in both cases, the superimposed introduction, into an observer's visual field, of an image given by an image generator. The image given by the light intensifier of a night observation system is processed in the same way as the image given by the image generator, by an auxiliary image-combining optical system which mixes these two images before they reach the main image-combining optical system of the device through which, in night vision, the observer directly sees the external scene. The auxiliary image-combining optical system is designed so that, in night vision, at least the greatest part of the light coming from the image generator reaches the main image-combining optical system. Depending on the embodiment, this result is obtained either with a retractable semi-reflecting mirror or with a semi-reflecting surface selective in frequency.

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: An optical system for a microscopic spectrometer includes an objective, an inverse placed telescope for relaying the image formed by the objective towards a detecting element, and an optical element for focusing the relayed image onto the detecting element. In the preferred embodiments, the inverse placed telescope is disposed after the image plane of a Cassegrain objective, and a paraboloid mirror collects the relayed light from the inverse placed telescope to be focused into an image on the detecting element. The inverse placed telescope has a smaller shading coefficient than the Cassegrain objective, and the size of the image of the pupil of the Cassegrain objective is smaller than the diameter of the secondary mirror of the inverse placed telescope. The image of the shaded diameter in the preferred embodiment, which is caused by the secondary mirror of the Cassegrain objective, is greater than the shading diameter caused by the inverse placed telescope itself.

Abstract: A pupil/image reversal prism (FIG. 2) forms a pupil at an image location. Such a prism has specific applicability in a DCR scheme for a thermal imaging system (FIG. 3a, 31 and 32) in which a passive DCR source is implemented by a pupil imager that forms a pupil onto the image of a thermal scene, thereby providing scene-average radiation to a thermal detector array. The pupil/image reversal prism including an input reflective surface (A), an output reflective surface (B), a positive reflective surface (C) and an intermediate folding reflective surface (D). The reflective surfaces A and B use total internal reflection to provide both transmissive and reflective operation.