Abstract: A first lens group U1 having a positive optical power, a second lens group U2 having a negative optical power and a third lens group U3 having a negative optical power are disposed in the order from a screen end. For focusing action, the first lens group U1 and the second lens group U2 respectively move in a same direction for different quantities, while the third lens group U3 remains fixed. The aperture ratio of projection lens as a whole is 1:1.1, the magnification of projection is in a range of -0.025 to 0.100.

Abstract: The object of the present invention is to present an acoustooptical modulator without ripples in its wavelength loss characteristics. In order to achieve this objective, the present invention provides an acoustooptical body 8 having a piezoelectric vibrator supplying, for example, ultrasonic vibration, to modulate the incident optical signal, an acoustooptical medium rotated 90.degree. on the crystal axis of the acoustooptical medium upon which the optical signal emitted from acoustooptical medium is incident, and eliminates the polarization mode scattering caused the birefringence of both acoustooptical medium and acoustooptical medium.

Abstract: The invention provides a prism optical system which has an image-forming action and provides a clear yet substantially undistorted image at a wide field angle. In a prism optical system 5 comprising an aperture 1 and having an action on erecting an image formed by an objective, there are provided reflecting surfaces 31, 32, 33, 41, 42, and 43 for image inversion, each of which is constructed of a curved surface having a power, and is in an irrotationally symmetric plane shape having no rotationally symmetric axis both within and outside the surface, so that decentering aberration produced by reflection of light at the curved surfaces can be corrected.

Abstract: Thin film AMA is disclosed. The thin film AMA has an active matrix, a supporting member, actuating parts and a reflecting member. The supporting member has a supporting line, a rectangular ring-shaped supporting layer, anchors. Insulating members are formed from top electrodes to the supporting layer. The anchors supporting the actuating parts are formed perpendicular to the actuating parts. The initial tiltings of the actuating parts are prevented because the stress concentration line doesn't generated. Therefore, the desired reflection angle of the reflecting member may be regular, so the light efficiency is enhanced and the quality of the picture projected onto the screen is increased. Also, the electrical shorts generated between the top electrodes and the bottom electrodes may be prevented by the insulating members, so point defects of pixels are effectively decreased.

Abstract: A method for manufacturing a polarization inversion part on the substrate of a ferroelectric crystal that is suitable for the use as a light wavelength conversion element or the like. A deep polarization inversion part or a homogeneous polarization inversion part is formed by one or more of: reinverting polarization in a part of the polarization inversion part; inverting polarization while applying a voltage also in the perpendicular direction to the polarization direction of a crystal; forming a low resistance part between electrodes to which an voltage is applied; inverting polarization from a electrode formed in a concave part on the surface of a substrate; applying a high voltage utilizing a insulating film; or the like.

Abstract: A device for fastening an optical unit to an actuating ring of an actuating device including a fastening ring joined to the actuating ring and having a plurality of securing shims bonded to the optical unit and connected to the fastening ring by flexible axial tongues. The device can be applied to a triaxial laser gyrometer.

Abstract: A lens system has the first and second lens components from the object side. The first lens component has a negative optical power. The second lens component has a positive optical power. The lens system fulfills the conditions: 0.0<PR.sub.L /Y'<0.5, 0.5<Pf/f<1.0. In the conditions, PR.sub.L represents a distance in a direction perpendicular to the optical axis between the optical axis and an incident position where a lower ray of a most off-axial rays enters said second lens component, Y' represents a largest image height, f represents a focal length of the entire lens system, and Pf represents a focal length of said second lens component.

Abstract: Disclosed is a fresnel magnifying lens card holder dimensioned to fit standardized cards, for example, all credit card sized cards. The card holder features a pair of parallel tracks, for example, J-shaped tracks which face each other, and a raised narrow strip on a base plate thereby facilitating the slipping on and off all such cards and, at the same time, using the cards themselves as a carrier, as a storage place and as a delivering vehicle of the fresnel lens. That is, the holder can take advantage of the popularity of the standardized cards, using them as its carriers in delivering a fresnel magnifying lens and a data stripe shield to the credit card users. Since keeping the data stripe from damage and helping to see small print clearly make the card friendlier to the user, providing these benefits could be of significant importance to both the card using public and to those who are marketing products and services.

Abstract: A lens barrel of the present invention includes a fixed frame, a plurality of lens groups disposed on the inner circumference of the fixed frame movably along an optical axis direction with respect to the fixed frame, at least three lens holding frames for holding at least one lens group of a plurality of the lens groups, a cam frame having bottomed cam grooves to be coupled with the inner circumference of the fixed frame through cams, bottomed cam grooves across each other to be coupled with the lens holding frames through cams and a bottomed cam groove which is discontinued on one end surface and continued from the other end surface.

Abstract: A gradient index lens which reflects light and focuses a corresponding image. The reflector can be easily incorporated to optical devices, and is particularly suitable for encoders position detectors, or other instrumentation utilizing line gratings.

Abstract: An imaging lens device at f/4 has zoomlike variable chromatic and spherochromatic correction for imagery in each of the astronomical U, B, V, and R bands. This lens system can thus take advantage of the full usable wavelength range of CCD cameras extending from 0.35-0.9 micrometers. A first triplet lens group effects the chromatic correction by altering separation between lens elements of the triplet while a second triplet lens group maintains a sharp image focus.

Abstract: The present invention eliminates the relay lens systems found in conventional helmet mounted displays (HMDs) by removing field distortions and aberrations with a contoured fiber optic faceplate placed in close proximity to a liquid crystal display (LCD) or cathode ray tube. The optical system typically consists of a spherical dielectric or holographically made collimator-combiner, a dielectric or holographically made fold mirror, and a contoured fiber optic faceplate. The fold mirror is flat, and the collimator-combiner is made by coating a spherical eye glass blank. The system is configured as a folded and tilted catadioptric projector with the novel feature being the contoured faceplate. There are no dispersive elements in the imaging assembly which means it can be completely polychromatic (full color) without the need for additional color correction optics as found in all refractive color systems.

Abstract: A polarizing conversion device in accordance with the invention includes a first optical element for condensing an incident beam and forming a plurality of intermediate beams spatially separated from one another, and a second optical element for spatially separating each intermediate beam into two polarized beams and aligning the polarization directions of the polarized beams, thereby obtaining the same type of polarized beams. In the second optical element, a shading plate is placed to prevent light from directly entering a section corresponding to a reflecting plane of a polarizing separation unit array. Since the ability of separating the intermediate beam into two polarized beams is thereby enhanced, it is possible to perform conversion into the same type of polarized beams polarized in the same direction, with high efficiency.

Abstract: A projection-type display apparatus including an elliptical condenser mirror having a concave reflecting surface consisting of part of a substantially elliptical surface, a light source arranged near a first focal point of the elliptical surface, a collimator lens having a focal point near a second focal point of the elliptical surface, and an optical modulation element array having a lens array on the collimator lens side, in which optical modulation elements each having an area S are two-dimensionally arranged.

Abstract: This invention provides a vision system that increases the field of view of an electronic binocular system without degrading image quality or requiring extremely large format sensors or displays. The vision system comprises an imaging device coupled with a viewing device. The imaging device comprises a compression lens and an image sensor. The viewing device comprises an image display and a decompression lens. The compression lens matches the optical distortion to the human visual acuity curve for field positions greater than an angle .theta.. Below angle .theta. there is substantially no distortion. The optimum angle .theta. depends on the application. For an average individual viewing a landscape the angle .theta. is about 10.degree.. For different viewing objects, the optimum angle .theta. varies from about 5.degree. to about 15.degree.. The image sensor can be infrared sensitive for infrared viewing.

Abstract: An optical module includes a resin housing having an optical axis, a semiconductor device held in the resin housing in alignment with the optical axis, and a lens held in the resin housing in alignment with the optical axis. The resin housing includes a lens holder disposed in facing relation to the semiconductor device. The lens holder has a lens grip member disposed around the optical axis and projecting toward the semiconductor device. The lens grip member has a distal end projecting radially inwardly. The lens holder also has a lens seat at a proximal end of the lens grip member. The lens grip member and the lens seat are integrally molded with the resin housing. The lens is held by the lens seat and gripped by the lens grip member after the lens is forced past the lens grip member toward the lens seat. The lens grip member comprises three lens grip fingers circumferentially spaced at equal angular intervals.

Abstract: The invention is directed to a pancratic system in an optical apparatus having a guide tube wherein at least one lens is moved in the guide tube. At least two guide rails are provided between the lens and the guide tube for guiding the lens. The surfaces of the intermediate spaces between the guide rails are configured so as to be poorly reflective and the space between the guide rails is also configured so as to be poorly reflecting.

Abstract: An optical isolator comprises two polarizers arranged before and after an optical rotator and a magnet surrounds the optical rotator. The magnet may generate a magnet field with a direction in spatial space parallel to the propagation direction of light traveling in the optical rotator and a strength sufficient to rotate the light to a predetermined rotation angle. Preferably, the polarizers are birefringent wedges of identical shape and optical properties. The magnet in accordance with the present invention may have a pair of magnetic adapters to generate the desired direction and strength of magnetic field. The direction of magnetic field varies in three-dimension space as the magnet is adjusted. The present invention provides an optical isolator of high isolation for high-volume mass production at a low cost. In particular, it may be easily operated at different wavelengths to achieve desired isolation without sacrifice of other optical properties of the optical isolator.

Abstract: A zoom lens barrel includes a front lens holder frame with a male helicoid and a rear lens holder frame including a cam follower pin. A linear movement guide mechanism guides the front and rear lens holder frames to move in the optical axis direction. A rotatable drive ring, with a female helicoid, engages with the male helicoid of the front lens holder frame and with a cam groove in which the cam follower pin of the rear lens holder frame is fitted. The cam groove is provided with a plurality of spaced back focal distance adjusting sections parallel with the lead of the helicoids and with a plurality of zoom sections that connect the adjacent ones of the spaced back focal distance adjusting sections and that are not parallel with the lead of the helicoids. The drive ring is always stopped when the cam follower pin is located in any one of the back focal distance adjusting sections.

Abstract: A spatial light modulator formed of a moveable electrode which is disposed opposite a fixed electrode and is biased to roll in a preferred direction upon application of an electric field across the electrodes to produce a light valve or light shutter. In one embodiment, the moveable electrode is restrained at one end and coils about the fixed end in a preferential roll direction. The bias is achieved by inducing anisotropic stress or anisotropic stiffness.