Abstract:
A tunable infrared detector employing a vanishing band gap semimetal material which is provided with an induced band gap by a magnetic field to allow intrinsic semiconductor type infrared detection capabilities. The semimetal material may thus operate as a semiconductor type detector with a wavelength sensitivity corresponding to the induced band gap in a preferred embodiment of a diode structure. Preferred semimetal materials include Hg.sub.1-x Cd.sub.x Te, x
Abstract:
An image sensing device is improved by an optical shield having a multi-aperture to provide high signal to noise ratio. The improved optical shield is provided with a plurality of shield elements forming a grid-like or cellular structure. With such a structure, the solid angle of the field of view for each sensing element becomes almost the same, resulting in the reduction of "shading". The distance between the heat shield and the array can be reduced, resulting in miniaturization of the device. Each sensing element is not shielded individually, so the pitch of the shield elements can be larger than that of the sensing elements, which allows easier and less costly fabrication of the shield.
Abstract:
La présente invention concerne une barrette de détecteurs infra-rouge (1) comportant un écran froid (2), du type assurant dans une direction perpendiculaire à l'axe de la barrette (XX') un angle de vue constant pour tous les détecteurs. Deux miroirs cylindriques (3, 4) sont disposés aux extrémités de la barrette et placés dans la partie chaude du cryostat contenant la barrette et l'écran froid. La forme, la dimension des miroirs, ainsi que, leurs positions sont choisies pour que le détecteur placé au centre de la barrette ne voit par réfléxion dans les deux miroirs que des surfaces froides, alors que les autres détecteurs voient par réflexion dans les deux miroirs des surfaces chaudes, selon une proportion qui augmente au fur, et à mesure qu'on s'éloigne du détecteur central de la barrette, de façon à ce que, selon l'axe XX' de la barrette, chaque détecteur ait un angle de vue sensiblement constant. Application aux barrettes de grande dimensions, pour les applications spatiales par exemple.
Abstract:
An apparatus for detecting electromagnetic radiation within a target frequency range is provided. The apparatus includes a substrate and one or more resonator structures disposed on the substrate. The substrate can be a dielectric or semiconductor material. Each of the one or more resonator structures has at least one dimension that is less than the wavelength of target electromagnetic radiation within the target frequency range, and each of the resonator structures includes at least two conductive structures separated by a spacing. Charge carriers are induced in the substrate near the spacing when the resonator structures are exposed to the target electromagnetic radiation. A measure of the change in conductivity of the substrate due to the induced charge carriers provides an indication of the presence of the target electromagnetic radiation.
Abstract:
Three means or methods for compensating for thermal noise, also referred to as dark signal, are utilized to enhance the accuracy of a monolithic diode array. A charge-coupled linear photodiode array (15) is used in a camera (40) to detect densities of any image projected or reflected onto the array. After conversion, voltage variations of one/one thousandth (1/1,000) volt in a ten volt range are significant to the measurement of densities. Therefore, extremely accurate control of thermal noise, which is generated in the cell sites and in the shift registers used to obtain the data from the cell sites, is extremely important. The three methods or means of control are as follows. Temperature control maintains the temperature of the photodiode array at approximately ten degrees centigrade to minimize the generation of thermal noise. A thermistor (T2) is used to detect any temperature variations within the range controlled by the cooling means and the reading is compensated for those variations in temperature. Finally, thermal noise generated in masked cells are measured and used as a correction or calibration for the readings. The foregoing means and methods enhance the accuracy of the readings by an order of magnitude.
Abstract:
The invention concerns an optical detection matrix (9) contained within a cryogenic chamber (3). Electrical image signals produced by the matrix (9) are converted into optical signals and transmitted out of the chamber (3) on lines 42A-42T. The optical signals on lines 42A-42T are converted into electrical signals carried on line (56).
Abstract:
PURPOSE:To uniformly form effective visual field angle in each segment element surfaces and to remove shading phenomenon by disposing a light shielding plate in mesh shape in a visual field deciding hole of a cold seal disposed opposited to a full photoreceiving element of an infrared ray receiving element. CONSTITUTION:A light shielding partition plate 22 having a vertical surface to the light receiving surface 2c of a photoreceiving element array is arranged in combination with a mesh state made of lattice in the visual field deciding hole 4 of a cold shield 3 opposite in the prescribed height to the full photoreceiving elements of an infrared ray receiving element array 1. The width L of the plate 22, the interval D between the plates 22, and the height H of the mesh light shielding plate 21 to the surface of the photoreceiving element 2 are suitably selected to aniformly specify the effective visual field in the respective photoreceiving surface 2c. Thus, the incident light amount to the array 1 is reduced toward the potoreceiving element 2b of the peripheral end via the photoreceiving element 2a at the center as a shading phenomenon can be remarkably reduced.
Abstract:
PURPOSE:To contrive dissolution of a shading phenomenon by a method wherein the visual field determining aperture part of the cold shield for the entire light- receiving element surface of an inflared ray light-receiving element array is constituted in blind form. CONSTITUTION:The titled device is constituted in such a manner that the visual field determining aperture part 5 of the cold shield 3 facing in the prescribed height against the entire light-receiving element surface of the inflared ray light- receiving element array 1 is arranged in said aperture part 4 so that it is positioned vertical to the light-receiving surface of the array 1 and that a plurality of light-shielding partition plates 21 are arranged in parallel and orthogonally intersecting with the direction of arrangement of the array 1. The angle of visual field on each light-receiving surface of the array 1 can be uniformly prescribed by each partition plate 21 by constituting the aperture part 4 in blind form as above-mentioned. The shading phenomenon generating on the light-receiving element 2a located in the center part of the array 1 and on the light-receiving element 2b on both ends can be dissolved by properly selecting the width of the partition plates 21, the intervals between each partition plate and the height of the partition plates 21 against the element surface.