Abstract: A scanning optical system which includes a light source for emitting a beam of light, a light deflector for deflecting the beam of light in a main scanning direction, and a scanning lens which receives a beam of light deflected by the light deflector for focusing the deflected beam of light onto a scanning surface. The scanning lens includes a lens having a refractive index distribution in either the main or the sub-scanning direction.

Abstract: The disclosure of the current invention describes a compact optical system for and method of forming an image on an intermediate image-forming surface such as a photoreceptor drum at a high speed. An image-forming light source such as a laser light source is placed between an image-focusing element such as a focusing mirror and an image-scanning unit such as a polygon mirror. According to one preferred embodiment, the image-forming light source is placed in a scanning area defined by a predetermined scanning angle of the image scanning unit.

Abstract: A multi-beam scanning optical apparatus of the present invention which is a multi-beam scanning apparatus which forms an image on a scanned surface via a plurality of laser beams, the laser scanning device has, a light source emitting a plurality of laser beams, a modulation device capable of switching the respective modulation frequencies of the laser beams, a deflection device deflecting the laser beams, capable of switching the scanning cycle of the laser beams, an axially symmetric optical system changing the distance among the laser beams on the scanned surface relative to a direction perpendicular to both an optical axis of the laser beams and a scanning direction by inserting itself into the optical path of the laser beams and a moving device inserting said axially symmetric optical system into the optical path.

Abstract: An improved polarization beam splitter formed by a collimator and two similarly shaped, birefringent crystal prisms is provided. The light from the collimator is incident upon the first face of the first birefringent crystal prism which also has second and third faces. The collimated light is incident upon the second face at an angle .phi. with respect to a line normal to the second face so that light polarized perpendicular to a plane of incidence upon the second face is reflected toward the third face and light polarized in the plane of incidence is refracted at the second face. The second birefringent crystal prism has a second face parallel to, and in close proximity with, the second face of the first birefringent prism so that light refracted at the second face of said first prism is refracted at the second face of the second prism and into the second prism.

Abstract: A rotary polygon mirror optical scanning device comprises a fixed shaft and a rotor having a shaft hole, to which the fixed shaft is inserted, and is rotatably supported against an outer perimeter of the fixed shaft. The device also includes a hydrodynamic bearing mechanism for supporting the rotor. The hydrodynamic bearing mechanism has first and second hydrodynamic pressure generating grooves which are, axially away from one another, formed on at least one of an outer surface of the fixed shaft and an inner surface of the shaft hole of the rotor. A rotary mirror is mounted on the rotor. A motor portion is arranged for rotating the rotor. The fixed shaft has a diameter bearing which is one-third or more of a diameter of a polygonal inscribed circle of the rotary polygon mirror. An area for cutting the first hydrodynamic pressure generating groove is arranged at an axially identical position with the rotary polygon mirror.

Abstract: An achrathermalized reimager includes a front objective defining an optical axis and a relay optic arranged on the optical axis downstream of the front objective. The front objective is both achromatic and athermalized and includes precisely one negative lens made of a material selected from the group consisting of ZnSe and ZnS and one positive lens made of chalcogenide glass.

Abstract: Rotating mirrors and methods for producing rotating mirrors with reduced variation in centrifugal distortion are disclosed. Pins (52) having a density different from that of the remainder of the body (51) of a rotating mirror are provided and located to reduce variation in centrifugal distortion when the mirror is rotated at high speed.

Abstract: In a hologram recording and reproducing apparatus including a hologram record element having a record unit formed by a photorefractive single crystal and a pair of electrodes provided on the record unit for applying a voltage to said record unit, and an optical system for impinging light onto an incident surface of the record unit, the record unit is made of a (100) wafer of Bi.sub.12 SiO.sub.20 or Bi.sub.12 GeO.sub.20 optical single crystal belonging to a cubic system, the light is made incident upon the (100) incident surface such that an optical axis of the incident light is inclined with respect to <100> axis of the optical single crystal by an angle .theta. of 30.degree.-60.degree.. The hologram record unit is immersed in an optically transparent and electrically insulating medium having a refractive index which differs from a refractive index of the optical single crystal by not larger than 0.

Abstract: This invention relates to electromagnetic wave beam paths, formation of the beam, illumination of programmable electromagnetic wave field vector orientation rotating devices ("PEMFVORD") with an electromagnetic beam, and the technique of projection of the modulated beam. This invention also relates to a unique light path and method of forming the light into a rectangular beam to be used for optical projection systems and, more particularly, in a color and/or black and white liquid crystal device (LCD) projectors that produce high resolution, high brightness and/or three-dimensional images. This invention further relates to a device capable of receiving and displaying two-dimensional and three-dimensional images.

Abstract: The intensified visual display relates to visual displays which combine generated images with the view of the environment surrounding a user and transmit such combined visual information to the eye position of the user. A fold mirror (1) frequently utilized in such displays reflects only a fraction of the light striking it and, similarly, transmits only a different fraction of the light reaching it. The fold mirror (1) will reflect a maximum amount of light when such light is S polarized and transmit a maximum amount of light when the light is P polarized. If the image generator produces S polarized light, one quarter-wave plate (3) is used to assure that image light to be reflected by the fold mirror (1) is S polarized while image light to be transmitted through the fold mirror (1) is P polarized. If the image generator produces P polarized light, a first quarter-wave plate (31) and a second quarter-wave plate (32) are employed.

Abstract: An apparatus is provided that includes a plate beamsplitter having a first surface coated with a partially reflective coating, and a second surface coated with an anti-reflective coating, and a polarizing filter, oriented with respect to the plate beamsplitter so as to substantially block light of substantially incompatible polarization that has traversed the plate beamsplitter, has been reflected by the object to be range imaged, and has been reflected by the plate beamsplitter towards the polarizing filter, thereby substantially preventing the formation of a ghost image of the object to be range imaged. Thus, the invention does not suffer from optical ghost images which commonly occur due to imperfect anti-reflection coatings used to make plate beam splitters. Also, the invention makes practical the use of plate beam splitters in depth from defocus and depth from focus range imaging systems employing coaxial active illumination and viewing.

Abstract: Polarizing element having a first layer and a second layer. When an unpolarized light beam is incident on the element, the direction of at least one of the polarization components of the unpolarized beam will be influenced by the first layer. These polarization components have different directions of polarization. The second layer influences the direction of a polarized beam incident thereon. A polarization-rotating layer is present between the first layer and the second layer. An unpolarized beam can be substantially completely converted into a polarized beam having mainly the same direction of polarization.

Abstract: Light from a light source is divided into P-and S-polarized beams by means of a polarizing beam splitter and converted into the same polarized wave. Two polarized waves are incident on a liquid crystal panel symmetrically at the same angle on right and left sides. An integrator comprising two lens arrays is disposed before and behind these polarization converting elements, and therefore brightness can be uniformly increased with a simple construction while achieving space saving.

Abstract: A color filter includes a plurality of color pixels, and a first hologram diffracting an incident light beam into a first diffraction-resultant light beam. The color filter also includes a second hologram diffracting the first diffraction-resultant light beam into a second diffraction-resultant light beam having a plurality of light beams with different wavelengths respectively. The second hologram directs the different wavelength light beams toward the color pixels respectively.

Abstract: This invention relates to methods and apparatus to control the light exposure of the skin. One objective is to increase the exposure during periods of common deficient exposure such as for dark skin persons on winter days in areas far from the equator. Another objective is to decrease the exposure during periods of common overexposure such as for light skin persons during spring and summer days in bright environments. A novel feature of the invention is the use of lamps for whole body irradiation while showering or bathing during dark seasons. The whole body exposure enables the use of very low irradiance levels to provide an enhanced probability of beneficial effects and to reduce the possibility of harmful effects of the ultraviolet light Another novel feature is the use of an adjustable ultraviolet light transmitting building window or automobile sunroof to increase the sunlight exposure on cold days when a deficiency in exposure due to closed windows is common.

Abstract: Use of an aperture in the reconstructed beam in reconstruction of multiple holograms increases selectivity beyond that realizable by spatial multiplexing so as to permit differentiation of overlapping images. "Aperturization" is suitably used for differentiation in the y-direction in shift holography, depending on Bragg selection in the x-direction.

Abstract: A head up display unit equipped at least with transparent and flat image information display means, transparent and flat light irradiating means arranged in an opposed and close contact relationship with the image information display means, light supply means for supplying light to the light irradiating means, image-display control means for controlling image display, and light-supply control means for controlling light supply. The display unit is a compact head up display unit which can be used in any place in the interior of an automobile.

Abstract: A miniaturized fingerprint sensor has a holographic phase grating glued to a base surface of a trapezoidal prism which operates on light totally internally reflecting from a finger-coverslip interface protecting the exterior surface of the grating, diffracting the reflected light to propagate back through the base surface and out the top parallel surface of the prism in a converging beam having an optical axis normally oriented (.perp.) with respect to such parallel base and top surfaces of the prism. A mirror folds the emerging converging light beam directing it into a camera system. The converging light beam emerging from the top surface of the trapezoidal prism contains high contrast, detailed images of ridges, valleys and pores of a finger-surface interface oriented in a plane normal to the optical axis.

Abstract: A substrate bears holographic imagery, selected portions of which are covered by non-holographic imagery printed in predetermined geometric registry with the holographic images. Multiple replicas of this interactive graphic work are mass-produced by embossing an array of the holographic imagery into a substrate in roll form, together with eyemarks located periodically along the roll. Using these eyemarks, the roll is optically sheeted and the non-holographic imagery then printed on the holographic substrate.

Abstract: An improved method for producing multicolor photographic images which resemble color photographs made prior to 1936. Light expressing a photographic image is passed through a transparent multicolor screen (20). Visual characteristics of the image are altered so as to produce darkened tonality, loss of acuteness, muting of hue, and a general sepia color cast.