Showing papers on "Apochromat published in 1990"

Diffraction bifocal with adjusted chromaticity

Abstract: A diffraction bifocal lens or lens system, comprising two profiled surfaces or interfaces or a linear combination thereof, wherein one profile provides for the bifocality of the lens and the other profile compensates for chromatic aberration. These lenses or lens systems exhibit two focal points, one which exhibits positive chromatic aberration and the other which exhibits negative chromatic aberration.

Apochromatic color correction using liquid lenses

Abstract: A new method of attaining apochromatic color correction in refractive optical systems has been developed. Common, low-cost optical glasses and abnormal dispersion optical liquids are combined to produce optical systems that have a degree of color correction which previously was possible only by using abnormal dispersion glasses or crystals. In addition to providing dramatic color correction these liquids have good availability, reasonable cost, and low light scatter. Two designs are presented: a glass-liquid apochromatic telescope objective which uses one abnormal dispersion liquid, and an athermal design which uses two liquids. Also presented are the theoretical and experimentally measured optical performance characteristics of these two lenses.

Color-corrected lens triplets with liquid lens elements

Abstract: A family of achromatic lens triplets and an apochromatic lens triplet are described, each of which consists of a fluidal liquid lens element (viz, Cargille 550206 liquid) contained between a Schott BK 7 glass lens element and a Schott F2 glass lens element

Apochromatic lens system

Abstract: The present invention is directed to an apochromatic lens system which is corrected for chromatic aberration at three wavelengths. The apochromatic lens system includes a plane glass and a plane lens which are interchageable with each other. When the plane glass is disposed on the optical axis of a lens system, the plane glass cooperates with the lens system to be corrected for chromatic aberration at the first and second wavelengths. On the other hand, when the plane lens is disposed thereon in stead of the plane glass, the plane lens cooperates with the lens system to be corrected for chromatic aberration at the first wavelength and a third wavelength.

Kinoforms long focal objectives for astronomy

Abstract: A new class of long focal apochromatic optical systems is described which permits the formation of images in different spectral ranges. The systems are composed of kinoform elements combined with conventional optical elements. The correction of monochromatic and chromatic aberrations is discussed theoretically with respect to their occurrence in long-focal, large-f-number astronomical lenses. Kinoform elements are compared to traditional optical elements, and the synthesis of long focal apochromats is shown to be possible with kinoform elements and typical optics. A discussion of diffraction efficiency and spectral selectivity in kinoform elements shows that acceptable characteristics for these optics can be achieved over a wide spectral range. Kinoform element objectives can be applied to high-resolution refractors, stellar sensors, large-telescope guiders, and collimators. The apochromatic lenses based on kinoform elements weigh 30-40 percent less than traditional lenses and offer high correction of chromatic aberrations, low thermal sensitivity, and a minor augmentation of stray light.

Low secondary color spectrum triplett

Abstract: An objective lens system for use with wavelengths in the visible spectrum, has first and second lens groups. The first lens group has one aplanat lens. The second lens group is a doublet. The second lens group is designed to correct for chromatic aberrations introduced by the first lens group. The power of the second lens group is inversely related to the index of refraction of the first lens group and the optical glasses of the lenses of the second lens group are selected to satisfy a novel color correction equation.

Design and fabrication of apochromatic HOEs for optical data processing

Abstract: Apochromatic Holographic Optical Elements (AHOEs) have been designed and developed using 633 nm wavelength in red sensitive photographic emulsion to work at 633 nm 5 14 nm and 488 nm with same focal lengths and equal efficiencies at each wavelength. These AHOES have been used for recognition of coloured targets and pseudocolouring.