Abstract: An optical pickup control system is provided for recording and reproducing information on various types of discs which have different reflectivities of light. The pickup has a semiconductor laser radiating a laser beam, and a photodetector detecting reflected light from the disc for controlling tracking and focusing of the beam. An automatic laser power control device is provided for controlling the power of the laser beam from the semiconductor laser such that the detected lights by the photodetector become a predetermined value.

Abstract: An optical pickup device includes: a stationary optical system for emitting a light beam and for producing a tracking error signal; and a rotary optical system rotatable around a rotary axis. The rotary optical system includes: a dividing unit for dividing the light beam emitted from the stationary optical system into a main beam and sub-beams; an objective lens for converging the main beam and the sub-beams on a recording surface of an optical tape and for receiving the main beam and the sub-beams reflected by the recording surface; and a guiding unit for guiding the main beam and the sub-beams to the objective lens and for guiding the main beam and the sub-beams reflected by the recording surface to the stationary optical system. The dividing unit, the objective lens and the guiding unit are arranged so as to be integrally rotated along with the rotary optical system, and the dividing unit is arranged on an optical path of the light beam between the stationary optical system and the objective lens.

Abstract: An optical pickup apparatus which adds the result of synthesizing the outputs of the individual elements of a photosensor for tracking servo to the difference between the outputs of those diagonally arranged elements of a photosensor for focus servo, thus yielding a focus error signal. This design eliminates the need for filters which have conventionally been essential to separate and extract a crosstalk component from a focus error component. This optical pickup apparatus can therefore produce a focus error signal from which the crosstalk component is effectively eliminated.

Abstract: An optical pickup includes: a laser diode for emitting p-polarized light, the laser diode having unit for controlling output power of the p-polarized light by detecting power of the emitted light in front thereof; a photodetector for receiving a laser light and outputting a signal corresponding to quantity of the laser light received; a polarization prism for transmitting and guiding the emitted light to an optical disc on which information is recorded by applying heat thereon, and for reflecting and guiding at least a portion of the light reflected by the optical disc to the photodetector. The optical pickup substantially satisfies the following conditions:60 [%].ltoreq.Tp.ltoreq.90 [%],14 [%].ltoreq.

Abstract: A laser power calibration device installed in a recording device for recording information on an optical recording medium includes: laser unit for emitting and irradiating a laser beam on the optical recording medium to record FM video signal and EFM audio signal; unit for varying recording power of the laser beam and duty of recording signal for driving the laser unit independently of each other; unit for reading the FM video signal and EFM audio signal recorded on the optical recording medium; unit for detecting carrier level of the recorded FM video signal and error rate of recorded EFM audio signal; and unit for determining optimum recording power of the laser beam so that the carrier level is higher than a first predetermined value and the error rate is smaller than a second predetermined value.

Abstract: A method of recording an optical disk, by irradiating a laser light onto a predetermined track of the optical disc to record information pits corresponding to an input composite signal including data signal and synchronization signal, includes the steps of: detecting a record timing of the synchronization signal to be recorded; and reducing at least one of a recording power and a recording duty of the laser light when the information pit corresponding to the synchronization signal is recorded by the laser light, according to the detected record timing.

Abstract: A device for recording information on a recordable optical disk includes: an optical pickup provided with laser unit for emitting and irradiating a laser beam onto the optical disk; radial tilt detecting unit for detecting tilt quantity of the optical disk in a radial direction thereof; tangential tilt detecting unit for detecting tilt quantity of the optical disk in a tangential direction thereof; radial tilt correcting mechanism for moving the pickup on the basis of the radial tilt quantity to correct the radial tilt; and tangential tilt correcting unit for controlling the power of the laser beam on the basis of the tangential tilt quantity.

Abstract: An optical pickup control system has an optical pickup for reproducing information recorded on an optical disc, a memory storing data on the position of a recorded area of the information and on the position of an unrecorded area of the disc. A control device is provided for controlling the pickup based on the data stored in the memory and stopping radial movement of the pickup on the disc when the pickup reaches the unrecorded area.

Abstract: A tracking error generating system is provided for generating a tracking error signal based on a laser beam irradiated on a writable optical disc by a pickup. Test data are recorded on a power calibration area (PCA) of the disc. A recording tracking error signal is obtained by jumping the pickup in the PCA, and the recording tracking error signal is stored in a first memory. A reading tracking error signal obtained through the tracking error generating system at reproduction of the optical disc is stored in a second memory. An adjusting circuit is provided for adjusting gain of the tracking error generating system so that the level of the reading tracking error signal becomes equal to the level of the recording tracking error signal.

Abstract: An optical pickup for an optical disc player has a laser for emitting a laser beam for optical discs which are different from each other in recording density. The laser beam from the laser is divided into two beams by a beam splitter. A first objective is provided for focusing one of the laser beams on one of the optical discs. A beam expander is provided for expanding an intensity distribution in the optical axis.

Abstract: A read-write head of a magneto-optical disc player has an optical head having an optical pickup, and a magnetic head having an electromagnet. The optical head and the magnetic head are each slidably held by guide members so as to be moved in a radial direction of an optical disc. A motor is mounted on each head for moving the head along the guide member. A relative position between both heads at a position where both heads oppose each other is detected, and both heads are moved along the guide members, maintaining the relative position.

Abstract: An optical disc apparatus continues the tracking operation even if a pickup reaches an unrecorded portion of a disc during the reproduction of an information signal. The apparatus discriminates whether the reading position of the pickup is at the recorded part or the unrecorded part according to a result of a comparison using a signal level read out, by the pickup, from a region other than a predetermined region. In accordance with the result of the discrimination, the tracking servo operation is switched to either one of a three-beam system and a push-pull system.

Abstract: A read-write head of a magneto-optical disc player has an optical head having an optical pickup, and a magnetic head having an electromagnet. Each of the optical head and the magnetic head is slidably held by guide members so as to be moved in a radial direction of an optical disc. Permanent magnets are mounted on both heads for attracting each other head. Thus, when one of the head moves, the other follows.

Abstract: A semiconductor laser control apparatus is used for controlling a semiconductor laser as a light source in an optical pick-up device for optically reading information on an information recording medium. The semiconductor laser control apparatus carries out emission or absorption of heat with respect to a semiconductor laser emitting a laser beam by a temperature control element arranged adjacently to the semiconductor laser on the basis of a current delivered from the power supply.

Abstract: A photodetector is divided into a pair of first segments and a pair of second segments by a common line. A total area of the first segments is larger than an area of a spot reflected from an optical disk onto the first segments. The second segments are provided within the first segments. A total area of the second segments is smaller than the spot. A detecting circuit is provided for producing a tracking error signal by removing a difference between outputs of the first segments and a difference between outputs of the second segments.

Abstract: An optical pick-up device comprises a light source, a light beam switching unit, a light intensity change unit and a signal detection unit including photodiodes.A light beam emitted from the light source and irradiated on an information recording medium has a wavelength for recording information and a wavelength, different from the former, for the reproducing information. The light beam switching unit carries out switching between a light having the wavelength for recording information and a light having the wavelength for reproducing information.The light intensity change unit transmits or reflects the light beam having the wavelength for recording information with attenuation to prevent a saturation of the photodiodes and transmits or reflects the light beam having the wavelength for reproducing information without attenuation. The light beam thus produced is detected by the signal detecting unit, and the servo control such as focusing servo, etc. is carried out on the basis of the detected signal.

Abstract: In the photo-detecting device, the light receiving surface of the light receiving element is divided into four sections A, B, C, D in the direction of tracking. To detect any tracking error, the quantities of received light on these four light receiving sections are used to calculate {(A+B)-(C+D)}-.alpha.{(A-B)+(C-D)}, where .alpha. is an adjustable value such as a variable resistance. Since this provides a true tracking error which does not include a dc offset, it is possible to make a correct adjustment of the tracking.

Abstract: An original disk having recording control data on a recording surface thereof and a blank disk having an unrecorded surface are coaxially disposed, and provided to be rotated by a spindle motor in opposite directions. A reproducing pickup for reading the recording control data on the original disk, and a recording pickup for recording data on the blank disk in accordance with the read out control data are coaxially provided. Both pickups are moved in a radial direction of the disk together in accordance with read out control data. Each pickup is independently moved in the axial direction for the focusing thereof.

Abstract: A position detector includes: light emitting component for irradiating the surface of an object to be measured; two light receiving components for receiving light reflected by the measured surface, a distance from one of the light receiving components to the measured surface as viewed in a direction substantially perpendicular to the surface being different from a distance from the other of the light receiving components to the surface; calculating circuit for calculating a correction quantity for correcting the distances between the light receiving components and the surface, with the correction quantity being calculated on the basis of a difference between the output signals of the light receiving components; and, moving component for correcting the distances between the measured surface and the light receiving components in accordance with the correction quantity. A first embodiment has two light receiving components each spaced at different distances from the surface.

Abstract: The light receiving element of the photo-detecting device of this invention has its light receiving area formed smaller than the diameter of a beam reflected from an optical information recorded disc. This makes it possible for the tracking error signal to be taken from a central area of the beam spot where the light intensity is high. This minimizes the dc offset caused by misalignment between the objective lens and the beam axis. The light receiving surface of the element is divided into at least four sections along a line at 45 degrees to the direction of tracking. A difference is taken between the light quantities received by two divided light receiving surfaces disposed perpendicular to the tracking direction. This differential signal allows adjustment to be made of an angle between the disc and the photo-detecting device in the direction perpendicular to the tracking direction.