Abstract: A projection method uses a modified illumination method for a lithography process of semiconductor device, and a projection system and mask use the projection method. An object is exposed by removing the vertical incident component of light passed through a condenser lens. Zero-order diffracted light interferes destructively and the oblique component of -/+ first-order diffracted light, interferes constructively. The obliquely incident component light illuminates a mask having a pattern formed thereon. The vertical incident component of the light is removed by a phase difference of light due to a grating mask or a grating pattern formed on the back surface of the conventional mask. The resolution of a lithography process is improved due to the increased contrast, and the depth of focus is also increased. Thus, patterns for 64 Mb DRAMs can be formed using a conventional projection exposure system.

Abstract: A dummy mask used in the fabrication of semiconductor devices, capable of forming an ultra-fine pattern by diffracting incident light while controlling or cutting off light components vertically incident on a mask formed with a pattern, thereby increasing the depth of focus and improving the resolution. The dummy mask includes a transparent substrate provided at its upper surface with a diffracting pattern for primarily diffracting light from a light source incident on the dummy mask and at its lower surface with a controlling pattern for removing vertically incident light not diffracted by the diffraction patterns.

Abstract: An image display apparatus includes an image display device such as, for example, a liquid crystal display panel, having a plurality of dot-shaped picture elements arranged in a two-dimensional pattern, and a diffraction grating disposed on an optical path through which imagewise rays of light emerging from the device travel. To minimize a reduction in quality and contrast of an image displayed by the device, the member has a spatial cut-off frequency chosen to be of a value lying between the sampling frequency, determined by the pitch between picture elements of the image display device, and the Nyquist frequency. For the same purpose, the intensity of .+-.1st order light relative to the intensity of 0-th order light in the diffraction grating is within the range of 60 to 80% at a center wavelength of the image display device, and the sum of the intensity of the 0-th order light and that of the .+-.

Abstract: A video color encoding apparatus (10 ) having a lens (14) for focusing an image (16) on an imaging element (20). The imaging element (20) has a monochromatic CCD imager (22) and a tricolor grating assembly (26) interposed between the CCD imager (22) and the lens (14) such that the image (16) is spatially and spectrally modulated onto the monochromatic CCD imager (22) in data compressed format. The image (16) can be reconstructed using conventional optical techniques with an optical reconstruction apparatus (46) or, alternatively, using mathematical means by a digital computer (42) to be displayed directly on a computer screen (54).

Abstract: An imaging device is formed by a transparent substrate having opposite surfaces on which are formed a plurality of micro aspherical lenses. The axes of the lenses on one surface coincide with the axes of respective lenses on the other surface. A two-dimensional micro lens array constructed by arranging converging lenses having a diameter of approximately several to several hundred micrometers is arranged ahead of a light source, thereby forming a multi-beam spot caused by diffraction in a distant position. A three-dimensional shape can be recognized with high precision by shape recognition means utilizing this multi-beam spot.

Abstract: An optical apparatus consisting of a laser for producing a coherent polarized beam of electromagnetic radiation of a preselected wavelength. A substrate of silicon has a first transparent cover layer for receiving the polarized beam substantially normally incident thereto, and a second transparent guide layer for receiving the polarized beam from the first layer and for supporting at least one resonant mode. The first and second layers have a preselected index of refraction and a grating is interposed between them, having a grating period less than half the preselected wavelength. The layers and grating interact to produce a standing wave resonance by Bragg reflection. A control obtains a resonance wavelength in the guide layer equal to the predetermined radiation wavelength and thereby high reflectance to modulate the polarized beam.

Abstract: In an optical filter to be used for signal selection, removal of noise, equalizing the wavelength of signal light, etc. in an optical communication system, optical measurement device or the like, and in an optical amplifier employing such optical filter, signal light is dispersed at different angles according to each wavelength by a diffraction grating and the dispersed light is selectively transmitted or reflected by a transmission type spatial filter or reflection type spatial filter, and is then coupled with an output fiber bundle as non-dispersed light by the diffraction grating. Thus, the optical filter has variable wavelength pass band characteristics and the optical amplifier possesses a uniform wavelength amplification factor.

Abstract: An image pick-up device with an electronic image sensor (IS.sub.1 IS.sub.2) is described, which includes a matrix of sensor elements (SE) and a low-pass filter for suppressing image frequencies exceeding the sampling frequency of the sensor. The low-pass filter has a first, composite filter function (F.sub.com) consisting of a variable component and a constant component and the device has a second filter function (F.sub.c) in conformity with the constant component which is optically or electronically subtracted from the first filter function.

Abstract: A self amplifying optical pattern recognizer includes a geometric system configuration similar to that of a Vander Lugt holographic matched filter configuration with a photorefractive crystal specifically oriented with respect to the input beams. An extraordinarily polarized, spherically converging object image beam is formed by laser illumination of an input object image and applied through a photorefractive crystal, such as a barium titanite (BaTiO.sub.3) crystal. A volume or thin-film difORIGIN OF THE INVENTIONThe invention described herein was made in the performance of work under a NASA contract, and is subject to the provisions of Public Law 96-517 (35 USC 202) in which the Contractor has elected to retain title.

Abstract: A pulse train in the presence of random noise and other pulse trains is identified by controlling pixels in a raster display in accordance with incoming signals; using the raster display to modulate a laser beam with the pulses; Fourier-transforming the modulated beam, then performing a Cartesian to polar coordinate transformation on the Fourier-transformed beam; inverse Fourier transforming the coordinate-transformed beam, and passing the result through a line spatial filter and focusing the filtered beam on a one-dimensional detector array.

Abstract: Coherent light from a laser is directed through first and second two dimensional planar arrays of lenslets which are moved relative to each other to enable the beam to point along any diffraction order, and fine pointing of the beam between orders is accomplished by slightly changing the angle of incidence of the beam with respect to the arrays. The laser is replaced by a photoreceptor when the scanner operates as a light beam receiver.

Abstract: An optical apparatus consisting of a laser for producing a coherent polarized beam of electromagnetic radiation of a preselected wavelength. A substrate of silicon has a first transparent cover layer for receiving the polarized beam substantially normally incident thereto, an a second transparent guide layer for receiving the polarized beam from said first layer and for supporting at least one resonant mode. The first and second layers have a preselected index of refraction and a grating is interposed between them, having a grating period less than half the preselected wavelength. The layers and grating interact to produce a standing wave resonance by Bragg reflection. A control obtains a resonance wavelength in the guide layer equal to the predetermined radiation wavelength and thereby high reflectance to modulate the polarized beam.

Abstract: Glints (e.g., images of point sources attributable to specular reflections) are suppressed in the focal plane of an optical imaging system by:a) Fourier-transforming an image of the imaging system's object field (including glints), and dividing the resulting energy distribution into a first channel and a second channel;b) focussing the energy in the first channel onto a first diffraction grating so as to impose a periodic carrier on the image, thereby producing a first image signal;c) directing the energy in the second channel so as to illuminate a Fourier-transform hologram of the complex point response of the imaging system to which additional aberrations (preferably toroidal aberrations) have been added;d) focussing the energy distribution from the hologram onto a second diffraction grating that is 180.degree. out-of-phase with the first diffraction grating, and blocking higher diffracted orders, thereby producing a second image signal;e) superimposing the first and second image signals (which are 180.

Abstract: Optical correlator technology is applied to optical computing in the form of an optical interconnect utilizing multiple Fourier transforms in a hologram-based design.