Abstract: The invention relates to a method of detecting a focus error signal of an optical head to be used for adjusting the position of an objective lens for converging a light beam on an optical recording medium and to an optical head and an optical recording/reproducing apparatus employing the method. The invention provides a method of detecting a focus error signal of an optical headwhich allows a focus error signal to be detected with track cross signals therein attenuated from a plural types of optical recording media having different physical track pitches and an optical head and an optical recording/reproducing apparatus employing the method. A main beam reflected by an optical recording medium is received by a light-receiving element, and electrical signals output from four light receiving regions of the element are used to generate a focus error signal MFES based on the main beam according to astigmatic focus error detection and a push-pull signal MPS based on the main beam according to the push-pull method.

Abstract: The invention relates to a method of detecting a focus error signal of an optical head to be used for controlling the focus position of an objective lens for converging a light beam on an optical recording medium and an optical recording/reproducing apparatus. The invention provides a method of detecting a focus error signal of an optical head which allows a focus error signal to be detected a track cross signal therein attenuated at a plural types of optical recording medium having different physical track pitches and an optical recording/reproducing apparatus employing the method. A light beam emitted by a laser diode is diffracted by a diffraction grating to split it into a main beam and two sub beams of orders of ±1.

Abstract: The invention relates to a heat-conducting member to conduct heat generated in a laser diode, an optical head using the same, and an optical recording/reproducing apparatus using the same, and has an object to provide a heat-conducting member to conduct heat generated in a laser diode. Besides, the invention has an object to provide an optical head in which various characteristics such as optical characteristics and electric characteristics are stable, and a lifetime of a laser diode can be prolonged, and an optical recording/reproducing apparatus using the same. A laser diode is fixed to a housing of an optical head by using a holder. A heat-conducting member is disposed between a base part of the laser diode and an FPC electrically connected to electrode terminals of the laser diode. The heat-conducting member functions to conduct heat generated in a light emitting part of the laser diode (heat conduction) and to release the heat to the holder for holding the laser diode and to the housing.

Abstract: The invention relates to an objective lens for converging light emitted by a light source to irradiate an optical recording medium with the convergent light, an actuator having the same, an optical head for recording information on the optical recording medium and reproducing information recorded on the same, and an information recording/reproducing apparatus utilizing the same. The invention provides an objective lens whose lens protecting section can be prevented from being coming off due to collision. The invention also provides an actuator, an optical head, and an optical recording/reproducing apparatus having the objective lens whose lens protecting section can be prevented from being coming off due to collision. An objective lens has a lens section and a lens peripheral section formed around the lens section integrally with the same.

Abstract: The invention relates to a light-receiving element for receiving a reflection of laser light irradiated to a rotating multi-layer recording medium having a plurality of information recording layers stacked one over another and for converting the light into an electrical signal, an optical head having the element for recording information in the multi-layer recording medium or reproducing information recorded therein, and an optical recording/reproducing apparatus and a method of optical recording and reproduction. The invention provides a light-receiving element, an optical head, an optical recording/reproducing apparatus, and a method of optical recording and reproduction which make it possible to eliminate a noise component superimposed on reflected light from a multi-layer recording medium to reproduce an RF signal of high quality.

Abstract: Beams of light emitted from a light source 1 are incident on a polarizer 14. In the event that the direction of a transmission axis of the polarizer 14 is adjusted in advance such that the polarizer 14 transmits P polarized light, only S polarized light can be attenuated. Beams of light which transmit through a diffracting device 2 and a collimator lens 3 for incidence on a beam splitter 4a are made up substantially only by P polarized light. Part of the beams of light, which is reflected on the beam splitter 4a, is incident on a photodetector 13 for use for feedback control of outputs from the light source 1. Since S polarized light is attenuated by the polarizer 14, only P polarized light is incident on the photodetector 13.

Abstract: The invention relates to an optical head and an optical recording/reproducing apparatus for recording information in an optical recording medium or reproducing information recorded therein and a method of optical recording/reproduction utilizing the same. The invention provides an optical head and an optical recording/reproducing apparatus capable of reproducing an RF signal of high quality by eliminating a noise component superimposed on reflected light from a recording medium and a method of optical recording/reproduction utilizing the same. The optical head has an RF signal extraction circuit for extracting an RF signal including information recorded in a rotating recording medium.

Abstract: Provided is an optical head, which is capable of performing output control for a light source without weakening an intensity of a light beam for recording and reproduction even if an optical element is not added anew, and an optical recording and reproducing apparatus including the optical head. Light fluxes near the center of an optical beam emitted from a light source are made incident on a diffractive element and transmitted through a beam splitter or the like to be irradiated on an optical recording medium. On the other hand, a part of peripheral light fluxes of the light beam are reflected in a direction substantially perpendicular to an optical axis by a reflection surface of a holder provided at an end of the diffractive element. Light beams reflected on the reflection surface are made incident on a photo-detector, and the photo-detector converts the light beams into an electric signal for output monitor of the light source according to an amount of received light.

Abstract: A beam emitted from a light source 1 is separated into a main beam and a sub beam by a diffraction element 2. Because the diffraction element 2 has a diffraction pattern shaped like sinusoidal wave, the spot of the sub beam becomes larger than that of the main beam. As a result, the sub beam little contains any tracking cross component which is generated when the spot crosses any one of tracks of an optical disk 5. Accordingly, when a signal output from a detector provided for detecting the sub beam is subtracted from a push pull signal of the main beam, it is possible to obtain a tracking error signal or a focusing error signal substantially containing no DC offset component.

Abstract: To provide a light receiving device, a light detecting device, and an optical signal reproducing device each of which allows one to perform many different computations in detecting aberration amounts and focus error quantities without requiring exact position relations between laser light to be received and light receiving elements, and between the light receiving elements.