Abstract: An optical encoder is provided which is not affected by fluctuation of wavelength of a light beam due to temperature change, without sacrificing resolution of measurement. The optical encoder comprises a light source emitting a light beam, a first grating to which the light beam emitted by the light source is directed, and a second grating to which light beams exiting from the first grating is directed. Additionally, displacement information obtaining means is provided for obtaining information for the displacement of one of the first and second gratings, the information being obtained according to a twice-diffracted beam and a twice-transmitted beam at the second grating. The twice-diffracted beam is generated from a diffraction beam generated at the first grating, and the twice-transmitted beam is a transmission beam which has been transmitted through the first grating.

Abstract: Method and display for providing a magnified image of a two-dimensional, periodic image pattern. An apertured sheet is arranged in front of the two-dimensional, periodic image pattern preferably being in a plane B and preferably in distance therefrom, the apertured sheet preferably also being in a plane A and in any direction to the plane having a center distance between the apertures, which almost corresponds to the center distance in the same direction in the plane B containing the periodic image pattern. As a result, a magnified image of the individual image element of the image pattern is obtained. Moreover, a stereoscopic depth effect may be obtained, if the apertured sheet and the image pattern are in different planes.

Abstract: A self-staining microscopic slide designed for immediate staining and viewing of cells in biological fluid and tissue samples, preferably with an epi-fluorescence microscope. The pre-prepared microscope slide preferably has a supravital fluorescent stain applied thereon, which is overlaid with a transparent tape or film. During use, the film is peeled back to expose the stain so that a sample can be applied thereon for intermixture therewith. The film is then replaced over the stained sample to act as a cover slip for immediate viewing. Living cells and microorganisms are rendered dramatically visible and cellular dysmorphology can be readily ascertained. The time and cost associated with preparing a fixed and sectioned sample is completely avoided as well as the problem of artifacts and sample fragmentation found in fixed preparations. The slide can include reference standards to facilitate microscope focusing, and to allow measurements of cells and microorganisms.

Abstract: An observer tracking display is provided in which the image data displayed by at least three image displays along respective different directions is updated depending on the lateral position of an observer. The image displayed in a viewing region not visible to the observer is updated with an appropriate image in anticipation of the observer moving to a position where that viewing region is visible.

Abstract: Apparatus are disclosed that perform, on demand, both near-field microscopy (NFM) and light-microscopy (e.g., bright-field microscopy or phase-contrast microscopy) of a specimen. The apparatus comprises an NFM microscope including an NFM probe, a first condenser lens system that converges a center portion of an illumination-light flux at a first terminus of the NFM probe, and a second condenser lens system that converges an annular portion of the illumination-light flux at a specimen to illuminate the specimen by Kohler illumination. Evanescent light from a distal terminus of the NFM probe passes to a locus on the specimen. Downstream optics capture light transmitted and/or scattered from the specimen from the NFM probe and from the Kohler illumination to produce both a light-microscope image of the specimen and an NFM image of the specimen.

Abstract: A light source device including a light emitting element emits a luminous flux, which is converged by a reflecting mirror. A conical light-refracting element receives the luminous flux converged by the reflecting mirror and changes the cone angle of the luminous flux. The luminous flux exiting the conical light-refracting element is diffused by a holographic diffuser and is then converged by at least one lens. The reflecting mirror may have an elliptic curvature or a parabolic curvature. The light source device is also used to form a projector for a projection type display apparatus. In the projector, the luminous flux emitted from the light source device may be separated by color separators into a plurality of colors of light. Then, each color of light is directed to the corresponding one of a plurality of light valves. Then, a color synthesizer synthesizes the colors of light emitted from the light valves into a composite image which in turn is projected onto a screen.

Abstract: A data carrier with an optically variable element has a layer regularly reflecting incident light and including interruptions. A diffusely scattering layer is disposed on the regularly reflecting layer so as to be visible through at least one interruption to provide at least one optically recognizable marking based on the differences in the reflectivities of the two layers at different viewing angles.

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: The twin-image elimination apparatus of the present invention comprises (a) a scanning light source for emitting a scanning light beam; (b) an interference device which converts the scanning light beam from the scanning light source into a spherical wave and a plane wave having temporal frequencies different from each other and combines the spherical and plane waves together; (c) a scanner for scanning an object with the combined light beam from the interference device; (d) a photodetector for detecting a scattered wave from the object; (e) a first multiplier which converts an output signal of the photodetector into a cosine-coded holographic information; (f) a second multiplier which converts the output signal of the photodetector into a sine-coded holographic information; and (g) a holographic reconstruction device which converts output signals of the first and second multipliers into a sum signal, in which these output signals are added together with a phase difference of .pi./2+2n.pi.

Abstract: Catadioptric projection systems are disclosed for projecting an illuminated region of a reticle onto a corresponding region on a substrate. The systems are preferably used with ultraviolet light sources (e.g., 193 nm). The systems comprise a first imaging system, a concave mirror, and a second imaging system. The first imaging system comprises a single-pass lens group and a double-pass lens group. The single-pass lens group comprises a first negative subgroup, a positive subgroup, and a second negative subgroup. Light from the illuminated region of the reticle passes through the single-pass lens group and the double-pass lens group, and reflects from the concave mirror to pass back through the double-pass lens group to form an intermediate image of the illuminated region of the reticle. The light is then directed to the second imaging system that re-images the illuminated region of the reticle on the substrate.

Abstract: A holographic scanner for scanning a surface with a light beam is provided. The holographic scanner includes a light source for emitting light used as the light beam, a front hologram for diffracting the light emitted from the light source to produce a first diffracted beam, a rotary hologram disk having a disk plane and rotatable around an axis thereof vertical to the disk plane, the rotary hologram disk including a plurality of scanning holograms arranged on the disk plane in a circumferential direction, the scanning holograms diffracting the first diffracted beam to produce a second diffracted beam, and a rear hologram for diffracting the second diffracted beam to produce a third diffracted beam, the third diffracted beam being used as the light beam for illuminating the scanning plane.

Abstract: The invention relates to a system comprising a series of data carriers, in particular identity cards, papers of value or the like, whereby the data carriers belonging to the system exhibit diffraction structures containing standard information and parts of the series are changed by additional measures in the area of the diffraction structures or combined with other elements and they differ from the rest of the series in optically recognizable fashion, whereby the change in the diffraction structures and/or the combination with other elements convey an esthetic overall impression and the change and/or combination with the other elements cannot be undone without destruction of the diffraction structures.

Abstract: A holographic imaging apparatus having a pulsed laser light source for generating an object beam and a reference beam whereby an object, obscured by a diffusing medium, is illuminated by the object beam. A real time interferogram recording medium is exposed to the coincidence of light reflected from the object and the reference beam to record an interferogram. A holographic image is then reconstructed from the interferogram and may be viewed and recorded. The pulsed laser light source generates a beam which is divided by a conventional beam splitter device into an object beam and a reference beam. The object beam is then diverged by a lens which forms a diverging object beam to illuminate the object. The reference beam is diverged through another lens to form a diverging reference beam which is directed so that it illuminates a photoreactive crystal.

Abstract: A chromatic aberration correcting element that is a simple lens having at least one aspheric surface the radius of curvature of which increases from the optical axis toward the periphery, at least either one of the surfaces being formed as a diffraction lens surface that consists of annular segments in steps that are shifted discretely in a direction in which the lens thickness increases as a function of the distance from the optical axis. Also, a chromatic aberration correcting device having annular segments formed in steps on either a light entrance face or a light exit face or both, the annular segments being composed of planes perpendicular to and concentric with the optical axis.

Abstract: Substantial improvements in photorefractive device lifetimes are provided by control of electron migration which results in the decay of gratings in photorefractive materials due to diffusion and other effects. A new class of photorefractive devices using compensating electronic and ionic gratings having relatively low efficiency but nonetheless usable gratings is provided by arranging the gratings to be reflective in a wavelength band outside the photo-excitation band of the photorefractive material, as by using an infrared operating wavelength. Longer lifetimes in high efficiency gratings are achieved by constant or periodic illumination of photorefractive materials to assure uniform charged distribution of electrons and maintenance of the ionic backbone grating.

Abstract: An inner focus type telescope includes a sighting objective lens, a focusing lens, a horizon compensating optical system, a focal plane, and an eyepiece through which an object image formed on the focal plane can be viewed, arranged in this order from the object side. The position of the focusing lens is adjustable to form the object image on the focal plane in accordance with the distance of an object to be viewed. The telescope further includes a beam splitting optical system provided in the optical path between the objective lens and the focal plane to split the optical path, a surface equivalent to the focal plane, provided in the beam splitting optical system, and a focus detecting system which detects the state of the focus at the equivalent surface.

Abstract: A projection screen is provided having a construction well-suited for effecting lateral color constancy in rear screen projection display systems. The inventive projection screen comprises a rigid light-transmissive faceplate and a homogenizing holographic transmission diffuser element proximate said faceplate. The holographic transmission diffuser element is made such that, upon illumination of an area of said diffuser element with a light beam having a wavelength of 400 nm to 700 nm, and impinging at an incident input angle of .+-.0.degree. to 30.degree.

Abstract: A method and apparatus (300) for making holograms includes a technique for exposing a film substrate (319) or other light sensitive medium to consecutive two-dimensional images, together representative of a three-dimensional system, to generate a three-dimensional hologram of the physical system. Low beam ratios are employed to superimpose multiple (20-300) images on the substrate (319). Each image is relatively weak, but the combination of the series of weak images ultimately appears as a single clearly defined hologram.

Abstract: A multi-wavelength optical filter for a portabe gas analyzer includes a filter assembly having a first opening and multiple additional openings. The first opening has a linearly variable filter disposed therein, while the additional openings have discrete filters disposed therein. The filters are linearly aligned, such that filter selection is facilitated by using the filter assembly with a linear positioning mechanism.

Abstract: Observation window, especially for checking the temperature of objects using infrared thermography, including a parallel-faced transparent insert made of a single crystal suitable for radiation to pass through without being substantially modified and/or attenuated, which radiation, whose wavelength may range from the visible to the relatively far infrared emanates from an object whose temperature is to be monitored, housed in a screened cabinet provided with a door or panel against which the window is arranged, wherein the insert is fitted into a support which surrounds it at its periphery and is immobilized with respect to the support, this support being applied in a sealed manner against an aperture made in the door and then locked in position by means which are only accessible from inside the cabinet, the support comprising an external protective cover capable of pivoting about a pin connecting it to this support, so as to reveal the insert and allow observation through it of the object to be monitored by