Abstract: An optical system for detecting a focus error signal in an optical disc according to the astigmatic method is constituted by a single lens element. This lens element has a first lens surface defined by a toric surface effective to converge the incident rays of light and also to produce an astigmatism. This lens element also has a second lens surface which has a negative power so as to form a telephoto optical system, making it possible to shorten the length of the optical system.

Abstract: An optical device comprises an optical lens and a mounting assembly for securing the optical lens to a support surface. The optical lens has a longitudinal axis and has first and second projections; the mounting assembly includes a clamp member which has a clamp surface and depresses the optical lens downwardly through contact of the clamp surface with the optical lens so as to mount the optical lens on the support surface. The clamp member is formed, on the clamp surface, with first and second holes engageable with the first and second projections of the optical lens, respectively; the second hole is an elongated opening extending in the longitudinal direction of the optical lens.

Abstract: A beam-shaping element for converting a beam having an elliptical cross-section into a beam having a circular cross-section. This element has a cylindrical entrance surface and a toriodal exit surface and can be arranged close to a diode laser so that the risk of wavefront deviations due to defocusing is reduced. The element has a high coupling efficiency.

Abstract: A synthetic resin lens for an optical system of a scanning optical system includes a synthetic resin lens having a light guide hole for directing a light beam at a light curable adhesive formed at a mount area thereof.

Abstract: A compact scanning optical system for effecting a superior tilt surface correction and for reducing a field curvature. The system is provided with a focusing optical system which is composed of a first single lens and a second single lens, wherein the first single lens, with a positive refracting power in a plane of scan, has a toric surface from an image plane and the second single lens, with a negative refracting power in the scan plane, has an aspherical lens.

Abstract: A toroidal lens (10) or a plurality of such lenses attached to a handle (14) for use as or in a keratoscope (12). If a plurality of lenses are employed, they are arranged either in different planes parallel to each other or concentrically in a single plane with varying degrees of ellipticity.

Abstract: A beam scanning optical system having a semiconductor laser for emitting a light beam; a cylindrical lens for converging the laser beam into a straight line; a polygon mirror for deflecting the laser beam which converged the cylindrical lens at a constant angular velocity; a spherical mirror for collecting the deflected laser beam on a surface of a photosensitive member; and a lens disposed between the polygon mirror and the spherical mirror, the lens having at least one toroidal surface. The lens is so disposed that its beam entrance side and beam exit side are decentered in a direction of the beam scanning, and curvature of the entrance side and curvature of the exit side on a plane of deflection have different centers. The entrance side and the exit side of the lens are a toroidal surface and a spherical surface respectively, and the spherical surface is decentered in a direction perpendicular to the plane of deflection in respect to the toroidal surface.

Abstract: A remote control system, in particular for locking and unlocking the doors of a motor vehicle, the system being of the type comprising a portable transmitter including means constituting a light source suitable for generating an encoded light flux, and a fixed receiver including photosensitive means designed to receive the light flux and associated with treatment means designed to decode it, wherein the photosensitive means of the receiver comprise a lens having a toroidal aspherical outside surface, which lens is associated with a plurality of photocells.

Abstract: An illuminating optical system for use in a microfilm reader/printer or the like for illuminating a film comprises an axially symmetric lens system and an anamorphic lens system. The anamorphic lens system includes a condenser lens opposed to a light source. The microfilm reader/printer having such an illuminating optical system causes the axially symmetric lens system to illuminate the microfilm during a reading operation, and the anamorphic lens system to illuminate the film during a printing operation.

Abstract: A scanning optical system used for light beam scanning device is disclosed. The scanning optical system is disposed between a deflector for deflecting a light beam and a plane to be scanned. In the scanning optical system, a spherical lens having a positive power and a toric lens are arrnaged. The toric lens is positioned close to the spherical lens at the side thereof closer to the plane to be scanned. The toric lens has positive powers both in the main and sub scanning cross sectional planes. At least one of the faces of the toric lens is aspherical in the main scanning cross sectional plane.

Abstract: Source of laser radiation for a printer includes at least one laser diode array and an optical system which is telecentric in at least one azimuth for imaging the near field distribution from the laser diode array(s) on a recording medium.

Abstract: An optical element for collimating and rectifying divergent incident radiation comprises a first optical surface and a second optical surface titled with respect to the first optical surface. The first optical surface has sufficient power to collimate incident radiation, while the second optical surface is tilted sufficiently to provide rectification.

Abstract: A reflective-type photoelectric switch projects emitted light from a light-emitting element toward a detection zone by a light-projecting optical system, and guides reflected light from an object to be detected in the detection zone to a light-receiving element by a light-receiving optical system. A special optical element is used in part of at least one of the two optical systems. The optical element functions to diverge light in a direction parallel to a plane containing the optic axes of the light-emitting and light-receiving elements, and condense light in a direction perpendicular to the same plane. As a result, it is possible to detect, with excellent sensitivity, both an object which is far from the switch and an object very near the switch.

Abstract: A light deflector has a focusing optical system for focusing a light beam deflected by a light deflector onto an object surface. The focusing optical system comprises, in order from the light deflector, a single anamorphic lens, a single spherical lens having a positive refractive index, and a single lens having a toric surface, the lenses having refracting surfaces having respective radii of curvature indicated respectively by r:1, r:2, r:3, r:4, r:5, r:6 in order from the light deflector. The light deflector meets the following condition:-1.0<r:6Y/r:2Y<-0.3where Y is a component of each of the radii of curvature in a direction normal to a main scanning direction in which the light beam is deflected.

Abstract: In an optical scanner, a light beam from a light source is formed as a line image extending in a main scanning corresponding direction and is deflected at an equal angular velocity by a rotary polygon mirror having a reflecting face in the vicinity of an image forming position of the line image and is then formed by an image forming lens system in the shape of a spot on a scanned face to optically scan the scanned face. An f.theta. lens system focuses and forms the light beam deflected by the rotary polygon mirror as an image on the scanned face. The f.theta. lens system comprises a functional device having a function for connecting a reflecting position of the rotary polygon mirror and the scanned face in an approximately conjugate relation with respect to a secondary scanning direction and an f.theta. function with respect to a main scanning direction; and two groups of first and second lenses are sequentially arranged from the side of the rotary polygon mirror toward the scanned face side.

Abstract: An optical system particularly for a laser beam printer comprising a semiconductor laser, a collimating lens, a cylindrical lens having curvature in the sub-scanning cross section, a deflector and anamorphic scanning lens system concentrating the light on a scanning plane. The anamorphic scanning lens system may have one to four lenses but has one lens with a convex toric surface facing the scanning plane. The anamorphic scanning lens system has stronger power in the sub-scanning cross section than in the main scanning cross section.