Abstract: A tilt servo control device of an apparatus for recording information on and reproducing information from an optical recording medium set in the apparatus, the apparatus comprising an optical system for leading a laser beam emitted from a light source to a recording surface of the optical recording medium and a laser beam reflected by the recording surface of the recording medium to a photo detector and a read signal generator for generating a read signal in accordance with an output signal of the photo detector. The tilt servo control device determines a type of the optical recording medium, generates a tilt drive signal so as to reduce a tilt angle at a position of the laser beam irradiating the recording surface and an optical axis of the laser beam by a method for generating a tilt drive signal corresponding to the recording medium type, and drives a tilt angle adjuster for adjusting the tilt angle in accordance with the tilt drive signal.

Abstract: A laser light intensity controller includes a polarizing beam splitter for passing most of one of an x-direction polarization component perpendicular to a direction in which a laser beam emitted from a light source travels and a y-direction polarization component parallel with the traveling direction and for reflecting a little portion of the one polarization component as monitoring light, and a photodetector for receiving the reflected monitoring light to generate a light intensity signal. The controller drives the light source in accordance with the light intensity signal. The photodetector reflects the other of the x-direction polarization component and the y-direction polarization component and is not sensitive thereto, and absorbs the one polarization component and is sensitive thereto.

Abstract: A laser light intensity controller includes a polarizing beam splitter for passing most of one of an x-direction polarization component perpendicular to a direction in which a laser beam emitted from a light source travels and a y-direction polarization component parallel with the traveling direction and for reflecting a little portion of the one polarization component as monitoring light, and a photodetector for receiving the reflected monitoring light to generate a light intensity signal. The controller drives the light source in accordance with the light intensity signal. An optical element which passes passing only the one polarization component is installed between the light source and the polarizing beam splitter.

Abstract: An optical pickup device comprises an objective lens unit having an objective lens, a support member for supporting the objective lens and an objective-lens driving mechanism for driving the objective lens in a radial direction and a focusing direction of an optical disc in such a way that a light beam is focused on an information recording surface of the optical disc; and a main unit having an optical irradiation system which includes a light source for emitting a light beam and guides the light beam to the objective lens, and an optical detection system which includes a photo-sensor and guides reflected light from the information recording surface to the photo-sensor via the objective lens.

Abstract: A light beam is emitted by a light source, and an optical system separates the light beam into a main-portion and a sub-portion. The main-portion of the light beam is guided to an information storage medium. A monitor detector receives the sub-portion of the light beam and outputs a detection signal. A controller controls the output power of the light beam emitted by the light source based on the detection signal. Thus, the light beam of the sub-portion, which is not generally used as a light beam to be irradiated on a storage medium, can be efficiently used, and hence the output power of the light beam from the light source may be accurately controlled.

Abstract: A disc player having a prepit detecting circuit which can correctly detect prepits even if phases or amplitude levels of a plurality of read signals read out from a recording disc are deviated from each other. A phase difference between a first read signal and a second read signal read out by first and second reading elements arranged in two regions divided along the direction of recording tracks of a recording disc is detected. A first phase correction read signal is obtained by adjusting the phase of the first read signal by an amount according to the phase difference. A differential value between the first phase correction read signal and the second read signal is outputted as a prepit detection signal.

Abstract: A light beam is emitted by the light source. The optical system separates the light beam into a main-portion and a sub-portion, and guides the main-portion of the light beam to an information storage medium. The monitor detector receives the sub-portion of the light beam and outputs a detection signal. Then, the controller controls the output power of the light beam emitted by the light source based on the detection signal. Thus, the light beam of the sub-portion, which is not generally used as a light beam to be irradiated on a storage medium, can be efficiently used, and hence the output power of the light beam from the light source may be controlled with high accuracy.

Abstract: A light source is provided for emitting a first beam having a far-field pattern of an elliptic shape. The first beam is a linearly polarized light having a first polarizing direction in a major axis of the elliptic shape. A half-wave plate is provided for rotating the polarizing direction of the first beam 90 degrees, thereby changing the first beam to a second beam. A beam splitter is provided for changing the elliptic shape of the second beam into a circular shape. The beam splitter is arranged to transmit the second beam and to reflect a third beam having a polarizing direction different from that of the second beam by 90 degrees. A quarter-wave plate is provided for transmitting the second beam from the beam splitter to apply it to an optical disc, and for changing the second beam reflected from the optical disc into the third beam. The third beam reflected from the beam splitter is applied to a photodetector.

Abstract: An optical pickup apparatus is provided with: a light source (20) for emitting a light beam; an optical system (21, 22, 24, 25, 26, 27), which comprises an optical element (24) having an incident surface (24a), to which an AR (Anti-Reflection) coat is not applied and to which the light beam emitted from the light source is inputted obliquely by a predetermined incident angle, for guiding one portion of the emitted light beam transmitted through the incident surface onto an information record medium (32) and guiding a reflection light of one portion of the emitted light beam reflected from the information record medium, and also reflecting another portion of the emitted light beam by the incident surface; a main light detector (30) for receiving the reflection light from the information record medium guided by the optical system and outputting a main detection signal corresponding to record information recorded on the information record medium; a monitor detector (23) for receiving another portion of the emitt

Abstract: An optical pickup device including an optical system which includes a first optical path which introduces a laser beam emitted from a light source to a recording surface of an optical disc through an objective lens and a second optical path which introduces the laser beam reflected on the recording surface of the optical disc to an optical detector through the objective lens, and an optical element which is disposed at least in the first optical path such that the optical element is movable in the optical axis direction of the laser beam.

Abstract: A light source is provided for emitting a first beam having a far-field pattern of an elliptic shape. The first beam is a linearly polarized light having a first polarizing direction in a major axis of the elliptic shape. A half-wave plate is provided for rotating the polarizing direction of the first beam 90 degrees, thereby changing the first beam to a second beam. A beam splitter is provided for changing the elliptic shape of the second beam into a circular shape. The beam splitter is arranged to transmit the second beam and to reflect a third beam having a polarizing direction different from that of the second beam by 90 degrees. A quarter-wave plate is provided for transmitting the second beam from the beam splitter to apply it to an optical disc, and for changing the second beam reflected from the optical disc into the third beam. The third beam reflected from the beam splitter is applied to a photodetector.

Abstract: A light source is provided for emitting a first beam having a far-field pattern of an elliptic shape. The first beam is a linearly polarized light having a first polarizing direction in a major axis of the elliptic shape. A half-wave plate is provided for rotating the polarizing direction of the first beam 90 degrees, thereby changing the first beam to a second beam. A beam splitter is provided for changing the elliptic shape of the second beam into a circular shape. The beam splitter is arranged to transmit the second beam and to reflect a third beam having a polarizing direction different from that of the second beam by 90 degrees. A quarter-wave plate is provided for transmitting the second beam from the beam splitter to apply it to an optical disc, and for changing the second beam reflected from the optical disc into the third beam. The third beam reflected from the beam splitter is applied to a photodetector.

Abstract: A recording power control device is capable of optimizing the recording power of a recording optical beam at every recording position on a DVD-R (recordable) disk while an optical disk drive is recording information on the DVD-R disk with the recording optical beam. Simultaneously with the recording optical beam, the disk drive emits an adjusting optical beam behind the recording optical beam in the direction in which information is recorded. The disk drive has a first photodetector for receiving the reflected recording optical beam and a second photodetector for receiving the reflected adjusting optical beam. The recording power control device is equipped with a laser drive circuit for setting the recording power of the recording optical beam according to an output signal from the second photodetector, which receives the reflected adjusting optical beam.

Abstract: An optical pickup (11) is provided with: a light source (2) for emitting a light beam (B); an objective lens (6) for condensing the emitted light beam onto an information record medium (1), which has an information record surface (1') for recording information thereon, from one external surface of the information record medium; and an immersion lens (7) disposed on an optical path of the condensed light beam between the objective lens and the information record medium for increasing a numerical aperture for the condensed light beam. The optical pickup is further provided with a floating device (33, 34, 40, 50, 45, 46, 47) for floating the immersion lens from the one external surface, such that a distance between a center of curvature of the immersion lens and the information record surface is within a predetermined tolerable range.

Abstract: A pickup for a recording and reproducing system has a hologram for dividing a laser beam from a laser diode into a main beam and a plurality of sub-beams. The hologram is provided to locate the sub-beams at positions rearward with respect to a scanning direction of the main beam.

Abstract: An optical record medium has an information record surface on which a plurality of circular arc tracks are arranged such that centers of the circular arc tracks are arranged in a straight line direction.

Abstract: An optical head emits a plurality of light beams onto an information record medium to perform a recording operation and/or a reproducing operation. The optical head is provided with: a plurality of light source, each outputting one of the light beams; an objective lens for collecting the light beams outputted from the light sources onto the information record medium; an optical element located on the optical path of only one of the light beams; a detector for receiving the light beam from the information record medium and outputting a detection signal; and a generating circuit for generating a drive signal based on the detection signal. The optical head is further provided with a dual-axis actuator for actuating the optical element in an optical axis direction of the light beam and in a substantially perpendicular direction to the optical axis direction in accordance with the drive signal.

Abstract: A rotary type pickup apparatus adopting a light modulation system, is capable of over-writing and suitable for miniaturization. In the optical pickup apparatus constituted by a stationary optical part and a rotary optical part which comprises an objective lens and a light beam guiding device, a recording magnet and an initialization auxiliary magnet are provided in the rotary optical part, the recording magnet being disposed close to the objective lens and the initialization auxiliary magnet being positioned over a rotation circumference where the objective lens rotates. Further provided are a recording magnet and an initialization auxiliary magnet which are disposed so as to pinch a magnetooptical recording medium together with the objective lens, the initialization auxiliary magnet being positioned behind the recording magnet in a sending direction of an optical card.

Abstract: A disc type identifying system for efficiently identifying one optical disc type from others having different recording formats, though having the same size and shape, is provided. The disc type identifying system comprises driver for rotating a disc to be identified a predetermined number of rotations; frequency detector for detecting frequency of a playback signal from the disc to be identified; and identifier for identifying the disc type based on the frequency of the playback signal detected when the disc to be identified is rotated the predetermined number of rotations. The predetermined number of rotations is set at the lowest linear speed among linear speeds defined in the different recording formats. Because the disc type may be identified in the process of a startup operation of a combination unit by constructing as described above, the startup time may be shortened, thus enhancing the efficiency of the system.

Abstract: A pickup apparatus of an optical card has an improved data transfer efficiency and miniaturization and thin shape of the apparatus can be realized. The length of a line segment connecting a center of an objective lens provided in a rotational optical unit and a center of a rotary drum is set to a length specified by a length in the major side direction on a recording surface of the optical card and (1+cos.theta./2). An optical pickup apparatus has: a fixed optical unit SOP; a rotary drum in reflecting mirrors for guiding a light beam B emitted from the fixed optical unit SOP to a recording surface of an optical card and an objective lens are mounted; and a rotational optical unit ROP having a rotary motor for rotating the rotary drum, wherein information is recorded and reproduced to and from the recording surface of the optical card.