Abstract: A compensating arm is provided extending from the proximal end at a joint to the distal end of a jib arm and arranged identical in the horizontal length to the jib arm. The compensating arm is pivotally joined at its distal end to the distal end of the jib arm and at its proximal end fixedly joined to a pivot which extends across the joint of the jib arm, whereby the pivotal movement of the jib arm about the joint is measured by an encoder which incorporates a compensator and is mounted to the joint with compensation of the relative movement of the pivot to the joint. This allows the encoder to detect the deflecting movement of the jib arm with the relative movement of the pivot to the joint compensated and thus locate the focal point correctly in the vertical direction.

Abstract: A radiographic film mask includes a planar sheet sized for receipt on an illuminated radiographic film examination box. The mask has two opaque sections and a transparent section. The transparent section is disposed on the sheet between the two opaque sections to form a radiographic film viewing area which has an area less than the entire area of the sheet. The sheet may include semi-transparent sections which border the viewing area and interconnect the opaque portions to provide reduced transmission of light along the marginal edges of the radiographic film.

Abstract: A multi-element refractive/diffractive lens system, especially useful in an interferometer of the Fizeau type for forming a partially reflective end of the cavity and focusing collimated laser light at a focus in the cavity, uses a plurality of lens elements all of which are plano concave or plano convex singlets and may be either spherical or cylindrical. The lens has a diffractive element which compensates for aberrations due to the refractive elements of the lens system and enables the lens system to be formed from relatively few refractive elements which are all plano-convex or plano-concave singlets thereby providing cost savings arising out of the reduction in the amount of glass material and number of lens elements. Since the lens system is especially suitable for use in a Fizeau type interferometer, it may be of the type called a Fizeau lens.

Abstract: A reflector is constituted by a right pseudo-dihedral, a ridge (C) of which is in the form of a portion of a helix so as to provide a calibrator or a beacon.

Abstract: Holograms and diffraction gratings are described wherein the presence of a "key-colour" (Magenta) permits an observer to identify the position where all the other colours of the hologram in question can be univocally determined. Two set of spectra are provided such that at a predetermined angle a reference beam of incident white-light illuminating the hologram or diffraction grating composition will cause the observer to see the color "Magenta" which is to be used as a reference "key-colour".

Abstract: Bit error rate in holographic storage/reconstruction is reduced by 2-dimensionally dispersing symbols constituting codewords so that no two codeword-common symbols occupy a single row or column on the SLM display.

Abstract: Apparatus and methods are disclosed for spatially routing an optical pulse (data pulse) of an electromagnetic radiation and containing a specific address temporal profile and possibly additional data. Routing generally involves a unit of active material that is programmed using one or more input beams or pulses of the electromagnetic radiation providing address (i.e., waveform-discriminating) and directional (i.e., pulse routing) information to the active material. During programming, a spatial-spectral grating is created by optical interference on or in the active material of the input pulses encoding the address and directional information pertinent to the data pulse.

Abstract: A method for making retroreflective sheeting comprising the steps of placing a light-transmittable protective film on glass beads in a support sheet which consists of a binder layer and a reinforcing layer, and which is provided with retroreflective glass beads embedded in the binder layer, and thermoforming parts of the support sheet under heating and pressure so as to partially bond the binder layer of the support sheet to the protective film, which is characterized in that the reinforcing layer of the support sheet consists of a crosslinkable resin having shearing stress S in the range of 6.times.10.sup.6 -1.2.times.10.sup.7 dyne/cm.sup.2 before the thermoforming. A retroreflective sheeting made by this method has a high uniformity of the joint portions of the support sheet and protective film. Even when this retroreflective sheeting is used outdoors for a long period of time, troubles including peeling-off of the protective film do not substantially occur.

Abstract: A projection type display apparatus includes a spatial light modulator, a polarizing beam splitter formed of members of a transparent material, and a projection optical system. The polarizing beam splitter includes a dielectric multilayer film, and a first transparent material member and a second transparent material member sandwiching the dielectric multilayer film. Each of the first and second transparent material members is made of a transparent material with a refractive index of at least 1.8 and with an absolute value of the photoelastic constant being no more than 1.5.times.10.sup.-8 cm.sup.2 /N for light of wavelengths 0.4 .mu.m to 0.7 .mu.m, incident to the polarizing beam splitter.

Abstract: A modulator for modulating incident rays of light, the modulator having a plurality of equally spaced apart elements, each of which includes a light reflective planar surface. The elements are arranged parallel to each other with their light reflective surfaces parallel to each other. The modulator includes means for supporting elements in relation to one another and means for moving particular ones of the elements relative to others so that the moved elements transit between a first configuration wherein the modulator acts to reflect the incident rays of light as a plane mirror, and a second configuration wherein the modulator diffracts the light reflected therefrom. In operation, the light reflective surfaces of the elements remain parallel to each other in both the first and the second configurations.

Abstract: A nonpolarizing beamsplitter is provided, which includes a multilayered stack of alternating layers of a first material and a second material. The first material layers are uniaxially birefringent, and the second material layers are optionally uniaxially birefringent or isotropic. The layers have index of refraction relationships such that for an incident beam having a useful bandwidth, a p-polarized component and an s-polarized component striking the beamsplitter at any angle of incidence .theta. within a desired range, the beamsplitter exhibits substantially the same average reflectivity for the p-polarized component of the incident beam as for the s-polarized component. The invention also includes a method of making a nonpolarizing beamsplitter.

Abstract: An optical isolator unit is aligned, assembled, and subsequently diced into smaller isolator chips for placement in a micro-optical bench, along with input and an output fiber coupling ball lenses. Polarizers (for polarization-dependent isolators) or birefringence walkoff crystals (for polarization-independent isolators) are aligned and then glued together with 45.degree. Faraday rotators using an optical-grade adhesive. The surfaces of the components are AR-coated to match the index of the optical-grade adhesive. An optical isolator unit formed in this manner is then diced into a plurality of optical isolator chips with a high-speed wafer saw. The optical isolator unit is preferably mounted on any one of its sides in such a way that only a smallest possible cutting depth is required for dicing, i.e., it is mounted such that a thinnest dimension of the isolator is presented for cutting, such that material loss due to cutting is reduced and delamination of the optical isolator chips is prevented.

Abstract: In an optical scanner, a deflected light beam is reflected on a reflective image forming element and is converged as a light spot on a scanned face through an elongated lens to perform an optical scanning operation at an equal speed. The reflective image forming element has a reflecting face with rotation symmetry and converges a reflected light beam onto the scanned face in a main scan-corresponding direction. The elongated lens has a barrel type toroidal face as an incident face and has a normal toroidal face as a light emitting face. The elongated lens sets the scanned face and the forming position of a linear image to a substantially conjugate relation in a cross scan-corresponding direction in cooperation with the reflective image forming element. A conjugate magnification m.sub.0 in the conjugate relation of the reflective image forming element and the elongated lens with respect to an image height 0 of the light spot satisfies the following condition:1>m.sub.0 >0.35.

Abstract: An infrared ray transmissive conductive substrate contains (1) a solid surface showing a transparency to at least the near infrared region and (2) an indium-tin-oxide containing transparent electrode having a sufficient light transmission property to at least the near infrared region formed on the solid surface. The indium-tin-oxide containing transparent electrode is formed on the solid surface by coating the solid surface with a solution containing an organic indium compound and an organic tin compound and thermally decomposing the organic indium compound and organic tin compound-containing solution.

Abstract: A thermoformed plastic laminar light-polarizing composite lens blank is produced from a laminate comprising a light-polarizing layer between polymeric layers. The absorption axis of the light-polarizing layer of the laminate is aligned to substantial parallelism with a principal index of refraction of the polymeric layer which forms the convex surface of the lens blank and which is birefringent, thereby to minimize retardation effects of the birefringent material on plane polarized light. The polymeric layer which forms the concave surface of the lens blank is substantially thicker than the opposed polymeric layer in order to accommodate grinding of the surface thereof to an ophthalmic prescription. Thermoforming of unitary portions cut from a supply of the laminate is performed under heat and pressure.

Abstract: A flexure structure for mounting an element such as a mirror in an optical device to a frame such as a telescope support structure includes a flexure blade defining a fork having three coplanar tines. A first mounting pad is located on the center tine for attaching the flexure blade to the mirror. A pair of mounting feet are located on the outside tines for attaching the flexure blade to the frame. The relative sizes of the tines being such that zero moment is applied to the mirror by the flexure structure when the mirror is displaced relative to the frame.

Abstract: The control of a mirror's shape, such as for use in large reflecting telescopes, is associated with discrete points so as to avoid incurring constraints and exerting undesirable stress on the reflecting mirror through control unrelated to the mechanical characteristics. Thus, a reflecting mirror is approximated by a non-constrained circular plate having a similar mechanical structure, and an eigenfunction value arithmetic unit calculates values of Bessel-Fourier functions which are eigenfunctions of free vibrations of the circular plate. Using these function values, a mode displacement identification unit approximates a required mirror displacement, which is necessary to correct for wavefront distortion, with a linear combination up to a prescribed mode of vibration of the eigenfunction. A support mechanism command unit controls an actuator so that the value of the linear combination function equals the amount of mirror displacement at a position supported by a reflecting mirror support mechanism.

Abstract: A hologram duplicating method and apparatus whereby a photosensitive material film is continuously and smoothly brought into close contact with the surface of a hologram original plate, and the film is effectively delaminated after a duplicating process. The apparatus includes a film supply part (31) for supplying a photosensitive material film (1), a film laminating part for successively laminating the supplied film (1) on a hologram original plate (35) with the film (1) being squeezed with a roller (46) from the upper side, a film delaminating part for successively delaminating the film (1) from the original plate (35) from one end thereof with the film (1) being pressed with the roller (46), and a film take-up part (43) for taking up the delaminated film. The film (1) can be laminated on the original plate (35) without trapping air bubbles, and the film (1) can be delaminated from the original plate (35) without causing peel unevenness such as undesired lines.

Abstract: A dual state mirror assembly for use with motor vehicles includes a housing having an open front for receiving an outer substrate to form an enclosure. The outer substrate has a surface coated with a thin metal film to act as a beam splitter. An inner substrate having a reflective front surface is mounted within the enclosure so that in a first position, the inner substrate is in direct contact with the outer substrate, to produce a single bright reflected image, and so that in a second position, the inner substrate is placed at an angle with respect to the outer substrate, to provide a dimmed image and to minimize glare.

Abstract: A viewing device adaptor, hatch insert, and overall mounting system allows viewing device to be releasably mounted through an existing vehicle opening of a vehicle. The viewing device includes a mounted periscope assembly extending from a body of a viewing device, with a collar bearing surface contiguous inbetween. A viewer adaptor releasably and rotatively mounts about the collar bearing surface. A hatch insert releasably mountable within a vehicle hatch opening including an opening for the releasable mounting of the viewer adaptor therewithin. When the viewing device adaptor is coupled about the collar bearing surface, and releasably mounted within the hatch insert that has been releasably mounted within the hatch opening, there results a substantially unobstructed field of view, with the viewing device within the vehicle rotatable from inside the vehicle.