Abstract: A scanning optical device includes a light source, a polygon mirror having a plurality of reflecting surfaces for deflecting a light flux emitted from the light source to form a scanning beam spot on an image surface, an identifying device that identifies which reflecting surface is currently scanning the light flux, a memory that stores data corresponding to shape errors of the reflecting surfaces, a correcting member that corrects a position of the beam spot, and a controller that controls the correcting member in accordance with an output of the identifying device and with data read from the memory. The correcting member is controlled to compensate for deviations of the beam spot due to tilt errors of the reflecting surfaces and may also be controlled to compensate for deviations of the beam spot due to an unevenness of the movement of the image surface.

Abstract: A wavefront aberration compensating apparatus for an optical data recording and reproducing apparatus to correct a wavefront aberration of light emitted from a light source and converged onto a data recording medium through an image forming optical system includes a liquid crystal matrix. The matrix has several liquid crystal elements in a matrix arrangement, and is located in an optical path between the light source and the data recording medium. Each liquid crystal element can independently control a phase of light incident thereupon. The compensating apparatus also includes a liquid crystal controller which individually controls the liquid crystal elements to minimize the wavefront aberration of a beam spot converged onto the data recording medium. The invention is also directed to an optical data recording and reproducing apparatus having the wavefront aberration compensating apparatus incorporated therein.

Abstract: A device including a polarizing beam splitter by which an incident luminous flux is split into a first luminous flux radiated onto a first photo sensor and a second luminous flux radiated onto a second photo sensor, and an adjusting mechanism provided for rotatably adjusting a position of one of the first and second luminous fluxes. The optical axis of the first luminous flux is coincident with that of the incident luminous flux. The optical axis of the second luminous flux is not parallel to the first luminous flux. By rotating the beam splitter about the optical axis of the first luminous flux, the beam receiving position of the second photo sensor, onto which the second luminous flux is radiated, is changed.

Abstract: A device for measuring a characteristic of an optical element which forms an interference fringe pattern using a reference light beam reflected from a reference surface and a test light beam that is guided from the optical element by a light refracting element. The interference fringe pattern is detected and data corresponding to the interference fringe pattern is output. The outputted data is processed such that information of wave front aberration representative of the interference fringe pattern is output. The information includes mathematical terms representative of position errors and of the characteristic of the optical element. The mathematical terms are calculated, and the mathematical terms representative of the characteristic of the optical element are corrected based on a value of at least one of the mathematical terms representative of the position errors. The corrected mathematical terms are then displayed.

Abstract: A scanning optical device that includes a light source that emits a light flux; a polygon mirror for deflecting the light flux; a scanning lens for converging the light flux deflected by the polygon mirror to form a beam spot on an image surface; a dynamic prism that is rotatably disposed between the light source and the polygon mirror to affect the direction of the light flux; a driving mechanism for rotating the dynamic prism to change the deviation angle of the dynamic prism; and a controller for controlling the driving mechanism to change the position of the beam spot during scanning.In particular, the controller rotates the dynamic prism to compensate for errors that affect the position of the beam spot on the image surface, such as errors that vary with time and errors that occur randomly during the scanning process.

Abstract: A housing includes a first portion and second portion. Each of the first and second portions supports a mirror and are connected and prevented from independent movement through a cover glass plate. The connection between the portions of the housing reduces the amount of angular change of mirrors within the housing resulting from a change in temperature, and thereby reduces the amount of displacement of a reading point of an image receiving element during the temperature change. The reading point is projected along an optical path including multiple reflections from the mirrors. A first connection device tightly fits the cover glass plate between the first and second portions of the housing, and a second connection device adheres the cover glass plate to the first and second portions of the housing.

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: A device including a polarizing beam splitter by which an incident luminous flux is split into a first luminous flux radiated onto a first photo sensor and a second luminous flux radiated onto a second photo sensor, and an adjusting mechanism provided for adjusting a position of one of the first and second luminous fluxes. The optical axis of the first luminous flux is coincident with that of the incident luminous flux. The optical axis of the second luminous flux is not parallel to the first luminous flux. By moving the beam splitter along the optical axis of the first luminous flux, the beam receiving position of the second photo sensor, onto which the second luminous flux is radiated, is changed.

Abstract: An apparatus and method for inspecting a beam splitter which is to be used in splitting a laser beam. The apparatus includes laser beam sources (including laser diodes and collimator lenses) for projecting a plurality of images through the beam splitter being inspected and onto a single photo detector. Based on the relative positions of the images on the photo detector, an accuracy characteristic of the beam splitter to be inspected can be determined. Each of the light beams emitted from the beam sources are transmitted through a condenser lens and through a pinhole provided in a diaphragm plate having a ground glass plate on an incident side. The pinhole provides a point source which is converted into a parallel beam by a lens. The beams are then made incident on the beam splitter to be inspected, are transmitted and reflected, and are emitted onto the photo detector in a relationship related to the accuracy characteristic of the splitter. The beams form images on a monitor connected to the photo detector.

Abstract: A detecting apparatus which detects an inclination of an objective lens relative to a reference surface is provided. The objective lens is part of an optical data recording and reproducing apparatus in which data is optically recorded on and reproduced from a recording medium which is placed parallel to the reference surface. The apparatus includes a transparent parallel plate which is opposite the objective lens, parallel to the reference surface, and made of a material that is substantially optically equivalent to a transparent material of the recording medium. The apparatus further includes a reflecting mechanism for reflecting coherent light which has passed through the objective lens and the transparent parallel plate back towards the transparent parallel plate and the objective lens, and a beam splitting mechanism for splitting the coherent light into a first beam and a second beam.

Abstract: An objective lens is corrected for spherical aberration at both an operating wavelength and a measurement wavelength, such that the amount of spherical aberration to develop at the operating wavelength is substantially equal to the amount of spherical aberration to develop at a measuring wavelength. The method of lens performance measurement then uses a light source emitting at a wavelength different from the operating wavelength.

Abstract: An optical system of an optical disc apparatus is disclosed for converging and projecting a bundle of rays emitted from a light source onto an optical disc. The optical system includes a collimating lens which collimates the bundle of rays emitted from the light source, two anamorphic prisms for shaping the cross section of the collimated bundle of rays transmitted through the collimating lens, and an objective lens which converges the bundle of rays shaped by the anamorphic prisms onto the optical disc. At least one of the anamorphic prisms is detachably mounted to an immovable body portion of the optical system.

Abstract: The optical disk apparatus of this invention is provided with a memory for memorizing a track offset signal corresponding to an angle of a galvanic mirror, or a photodetector having two pairs of photodetecting regions to detect different tracking error signals to each other, or two galvanic mirrors which are adjusted so as to prevent the track offset signal.

Abstract: This invention relates to a means of analyzing the shape of a surface to be measured by generating interference fringes containing a spatial carrier produced by tilting the wavefronts from a reference surface and the surface to be measured, taking several measurements of these interference fringes while varying the optical path length of the reference surface by means of a phase shift device, applying a spatial fringe scan method to the interference fringe data so as to detect the optical path length variation produced by the phase shift device, applying a temporal fringe scan method to this optical path length variation and several interference fringe data so as to analyze the interference fringes, and then subtracting the spatial carrier from the analytical results.

Abstract: A compound prism including a plurality of unit prisms which have reflective interfaces defined by outer and/or inner surfaces thereof and which are arranged so that light is reflected by an inner surface of the interface of one of the unit prisms and by an outer surface of the interface of another unit prism.

Abstract: An interferometer causes a reference beam and a subject beam reflected from a roof surface to interfere with each other to form an interference fringe, which is detected by an image detecting element in its measuring area. Detection data from the image detecting element is processed by an image processing circuit, and then subjected to phase difference detection. A continuous function is determined as an approximation to a relationship between phase data and unit measuring areas located in a direction perpendicular to a line corresponding to a ridge line of the roof surface. A analysis relating to a roof angle is performed based on the continuous function thus determined.

Abstract: A device in which an offset is added to a focusing error signal to control an objective lens and thereby reduce the generation of cross-talk when a beam spot that is converged on an optical disk crosses over a wall of a groove of a track of the disk. By adding the offset to the focusing error signal, the objective lens is moved out of focus with the disk. Thus, the shape of a beam spot formed on a photo sensor is changed from a circle to an ellipse. A condenser lens provided for forming the beam spot is moved along the optical axis thereof in such a manner that an output of a recorded signal of the disk is at a maximum value. As a result, the objective lens is brought into focus on the disk. Thereafter, the objective lens is focused on the disk in accordance with the focusing error signal to which the offset is added, while maintaining the beam spot in the shape of an ellipse.

Abstract: An optical axis adjusting apparatus is provided and includes a laser beam source, a beam shaping prism for shaping a laser beam of elliptical flux emitted from the laser beam source into a laser beam of circular flux, and an angle adjusting device which adjusts the angular direction of the outgoing laser beam emitted from the shaping prism.

Abstract: An optical axis adjusting apparatus is provided and includes a laser beam source, a beam shaping prism for shaping a laser beam of elliptical flux emitted from the laser beam source into a laser beam of circular flux, a parallel shift mechanism which shifts the light rays of the laser beam in a parallel fashion, and a rotation adjusting mechanism for rotatably adjusting a parallel plate.

Abstract: An apparatus for measuring a wave front aberration includes a light beam splitter for dividing a parallel laser light beam made incident from a measuring object into two beamfluxes, an image rotator disposed in at least one optical path of the divided beam fluxes for rotating the wave front on the optical axis, an interference device for interfering after superposing the beam fluxes whose wave fronts are rotated relatively, an imaging lens for forming the interfered beam into an image, and an observation device for observing the imaged interference fringes.