Abstract: An optical low pass filter for use in an imaging device including an objective lens and a solid state image sensor forming a plurality of picture elements thereon, which filter comprises a diffraction grating disposed between the objective lens and the solid state image sensor. The diffraction grating is of a type which the periodicity of an image of the diffraction grating projected onto the solid state image sensor by the objective lens is selected to be twice or 1/n of the periodicity of the picture element, wherein n represents an integer.
Abstract: A two-dimensional, white light illuminable arcuate rainbow hologram that is potentially viewable from 360.degree. is formed by limiting the information content of a wave front representing a reflection of monochromatic coherent light off of the object desired to be holographed. The information content is limited to a selected portion of the wave front, the selected portion passing through or upon an arcuate window which preserves the selected portion. The arcuate window is formed using an arcuate aperture, a flat arcuate master hologram, or a cylindrical shell of laser light used as a reference beam. The arcuate rainbow hologram is viewable from 360.degree. if the arcuate window is annular, i.e. circular. If the window is a half-circle or other arc angle, the window of viewability will correspond to the angle of the arcuate window that limits the information content of the wave front representing the reflection of monochromatic coherent light off of the object to be holographed.
Abstract: An improved rearview mirror and process for producing the same is provided wherein an elongated substrate member is configured for attachment to the interior of a windshield. The substrate member supports an image retaining coating defining a holographic reflective surface that is configured to be substantially normal to the line of sight of the driver despite the slope of the windshield. As a result, a thin distortion free mirror can be provided with an expanded line of sight for the driver.
Abstract: A microlens having pliability is disclosed, which comprises a layer of a polymer composition having the thickness gradually changed, the layer of the polymer composition being formed by exposing to light a layer of a photo-reactive composition selected from (i) compositions containing a photopolymerizable monomer and a photopolymerizable initiator or (ii) compositions containing a photopolymerizable polymer. A process for producing the microlens is also disclosed.
Abstract: A light beam scanning apparatus comprises an ultrasonic light deflector for diffracting a light beam of a predetermined wavelength, and a reflecting mirror positioned approximately normal to light deflected by the ultrasonic light deflector for reflecting the deflected light and making it again impinge upon the ultrasonic light deflector.
Abstract: Methods for generating holograms from a computer model of any object employ a combination of numerical and optical means. An illumination model and the light dispersion properties of the objects are specified. The hologram is synthesized from a plurality of smaller hologram elements. Each individual element sustains a field of view of the object. The light rays from the object lying within the field of view and along the lines of sight are sampled by the computer. The sample density should not exceed the resolution limit set by the size of the hologram element. Each light ray is specified by a direction and an amplitude function. The hologram element is obtainable from a Fourier Transform of the sampled rays. In one embodiment, optical means are employed to physically reproduce the sampled light rays using coherent radiation. The reproduced coherent light rays are then interfered with a coherent reference beam to form the hologram element.
Abstract: An intensity inverter includes an optically nonlinear medium and a reference beam having a uniform transverse intensity distribution and having the same wavelength as the signal beam. The reference beam is directed into the nonlinear medium. A readout beam having the same wavelength as the signal beam and counterpropagating with respect to the reference beam is also directed into the nonlinear medium. When the signal beam is directed into the nonlinear medium, the signal beam and the reference beam interact to form a hologram within the nonlinear medium, thereby diffracting a portion of the readout beam, the undiffracted portion of the readout beam having imposed on it an inversion of the signal.
Abstract: An improved optical combiner useful in many applications is disclosed. The combiner includes a substrate with at least one aspheric surface and an diffraction-type reflective coating formed on the substrate for selectively reflecting radiation within one or more predetermined narrow band ranges of wavelengths impinging on the coating. The aspericity of the surface may be selected to compensate or balance optical aberations. The coating is advantageously a graded-index coating, which eliminates the possible degradation of gelatin halogram coatings due to moisture. A process for applying the graded-index coating to a substrate is disclosed. The variation in the index profile of the coating can be selected to provide the capability of combiners with multiple color reflectivity responses, or which allow use of display light sources of wider spectral bandwidth, resulting in a brighter image and improved angular bandwidth.
June 20, 1988
Date of Patent:
November 6, 1990
Hughes Aircraft Company
Mao-Jin Chern, John J. Ferrer, Ronald T. Smith
Abstract: A hologram which comprises a light transparent base having coated thereon a hydrophilic water-swellable layer which contains the holographic image and a dye whose peak absorption is below the peak replay wavelength of the hologram. The hologram is produced by adding the dye after exposure of the hologram.
Abstract: This invention pertains to holography and particularly to a novel method for producing holographic stereogram images from a sequential series of two dimensional images generated on a liquid crystal display matrix. Further a liquid crystal display matrix is used to generate a vertical slit aperture for the masking of a halographic plate.
Abstract: In the present disclosure, a method of routing interconnections between a semiconductor module and another semiconductor module in a planar field by the use of a digital computer program is disclosed. The method is a variation of the prior art YACR method. The method provides for variable width track routing, as well as cost equation for net assignment and cost equation of net chosen to particular a horizontal track. The present invention also relates to a method for positioning the modules. The method of positioning the two modules or compacting the modules is a method for moving tracks between modules from one module to the other module as close to the opposite module as possible within the design rule constraints. The tracks are then moved in an opposite direction and the straightest segment to minimize jogs is chosen. Each track is then moved in the opposite direction and is moved as close to the straightest previous adjacent track as possible, within the design rule constraint.
Abstract: An optical beam splitting method and optical beam splitting/modulating method for recording halftone plate images on a recording material through controlling a light exposing device by image signals obtained by photoelectric manipulation of an original image. Two light beam splitters are used so that a single light beam can be split into a plurality of split light beams which are lined up in two rows and shifted by one-half pitch with respect to each other and then modulated in multi-channel ultrasonic modulators, one row of the light beams being modulated with a delay without causing crosstalk. The number of split beams to be modulated is approximately doubled compared to a conventional system, and the size of the dots on the recording material can be decreased so that the image resolution is remarkably improved.
Abstract: In an optical reflection preventing film comprised of a plurality of layers provided on an optical element, one of the plurality of layers is formed by a transparent electrically conductive layer, and the optical film thickness of the transparent electrically conductive layer is 45-120 nm.
Abstract: A multifocal lens is described with a main lens designed for distance vision and a segment designed for near vision.The lens in accordance with the present invention is characterized by the fact that one surface of the segment consists of the progression area and the reading portion of a progressive surface.In an advantageous further development the progressive surface whose progression area and reading portion form one surface of the segment is designed in such a way that its surface astigmatism is concentrated essentially in the distance portion.
July 18, 1989
Date of Patent:
September 11, 1990
Optische werke G. Rodenstock
Rudolf Barth, Gunther Guilino, Dieter Kalder
Abstract: A light beam is repeatedly deflected in the longitudinal direction through a holographic element HOE by means of a rotating multi-faceted mirror. This HOE is so formed that the beam entering at different angles leaves the HOE as a telecentric beam. Through a further HOE the telecentric beam is diffracted onto an opto-electric transducer. In the region of the telecentric beam is located an object to be measured, and the time of the interruption of the telecentric beam by means of this object enables the dimension of the latter to be determined. The production of the telecentric beam and the deflection of the latter onto the transducer by means of the HOE allows a simple cost-effect manufacture as well as a simple evaluation of the measurements with increased precision. The manufacture of the HOE is likewise simple.
Abstract: A quasi-periodic sequence of a plurality of types of layers is produced by selecting successive subsequences of the layers in response to at least one prior subsequence of the layers and a predetermined substitution matrix. In one specific illustrative embodiment, the substitution matrix is such that each successive term of a series corresponds to a Fibonacci sequence. Quasi-periodic structures produced in accordance with the present invention are produced simply and inexpensively without the need for very stringent manufacturing tolerances and controls. Optical embodiments of the invention yield highly desirable characteristics with respect to incident radiation in the ranges of X-rays, ultaviolet, and visible light. Additionally, electrical devices having unusual electrical characteristics can be produced.
Abstract: Web material for camouflaging against electromagnetic radiation whereby the material (1) comprises several layers (4, 5, 6) against the electromagnetic radiation which is directed against the material, whereby the material is provided with a front side (2), which is intended to be turned towards a potential observer or detector, as well as a backside (3), which is intended to be turned towards an object, which is to be camouflaged. The layers consist of a first layer (6), formed of a metallic foil (4), with at least one reflective surface toward the front side (2), a second layer (5), laid on the first surface of the first layer and chosen to be of a material which is absorbent for visible light and near-infrared radiation (wave length up to approximately 2 .mu.m) as well as transparent for thermal infrared radiation (wave length region 3-100 .mu.
Abstract: A method for promoting enhanced nondestructive reconstruction of holograms recorded in photorefractive media involves control of the polarization states of the reconstruction beam and the recording beams, control of the cummulative recording energy, and use of a relatively high external field applied across the media during recording which is subsequently reduced during reconstruction. The resulting reconstruction history characteristics are selectively tailored by adjusting the polarization and intensity of the reconstruction beam, the recording geometry, and the applied voltage during reconstruction and recording, and various other parameters. In general, the reconstruction efficiency starts at a relatively high level, initially reduces, and then subsequently grows above the starting value, and can be made substantially nondestructive over a typical reconstruction cycle, with erasure times exceeding forty-five minutes.
December 30, 1987
Date of Patent:
September 4, 1990
Microelectronics and Computer Technology Corporation
Redfield Stephen R., Lambertus Hesselink
Abstract: An apparatus for measuring the frequency of a pulse train signal and method therefor applicable to a speedometer of a vehicle are disclosed in which a count value C of at least one counter which counts number of pulses in the pulse train signal for predetermined counting intervals of time .DELTA.T (=T/n, wherein T denotes a frequency measuring time interval and n denotes a calculation constant) is updated to a value related to the count value for each predetermined counting interval of time .DELTA.T and stored and outputted for each predetermined counting interval of time .DELTA.T so that the same or better performance as that using a stagger ring method can be achieved. The value is expressed by (C-C/.alpha.) in a first preferred embodiment (wherein .alpha. denotes the calculation constant preferably equal to n), by (C-C.times.m/.alpha.+D) in a second preferred embodiment (wherein m denotes the number of counters and D denotes the latest count values of the m counters during .DELTA.
Abstract: An optical space switch is used in a centralized switching system for an optical network and connects light from one of a number of inputs (1) to a selected one of a number of outputs (6). The switch includes a number of multiplexed phase volume holograms (4), a spatial light modulator (3) for imposing a selected phase change on light passing through it, distribution means (2) for coupling light from the inputs (1) via the spatial light modulator (3) to the multiplexed phase volume holograms (4), and collection means (5) for collecting light diffracted by the multiplexed phase volume holograms (4). Each multiplexed phase volume hologram (4) diffracts light to a selected output (6) in dependence upon the phase change imposed by the spatial light modulator (3) on the light incident upon that hologram (4).
October 17, 1988
Date of Patent:
August 28, 1990
British Telecommunications public limited company