Abstract: After the initiation of writing, an output signal from an LPF is sampled in correspondence with a portion with a predetermined pulse width of recording data, so as to obtain a pit level. In the resultant signal, its varying portions which correspond to the multi-pulse trains of the write signal are smoothed. A controller modifies a level of a target level signal to be supplied to an APC circuit in such a manner that the pit level becomes an optimum pit level which has been obtained prior to the initiation of writing.

Abstract: An optical recording/reproducing apparatus having drive means for rotating a recording medium, an optical head for applying light to the recording medium being rotated by the drive means, thereby to record data signals on the recording medium or reproducing data from the recording medium, and a signal-processing circuit for processing a signal detected by the optical head. The optical head comprises a light source for emitting light, an objective lens, and signal detecting means. The objective lens has a numerical aperture NA, where 0.5<NA≦0.6. The apparatus can reliably record data on and reproduce data from high-density optical recording media that have different track pitches.

Abstract: An optical disc apparatus capable of mounting an optical disc includes a light source for emitting light: an objective lens for collecting the light emitted by the light source on the optical disc; a first light distribution section integrally movable with the objective lens, the first light distribution section including a first area and a second area, the first light distribution section outputting the light reflected by the optical disc and transmitted through the first area or the second area as transmission light, outputting the light reflected by the optical disc and diffracted by the first area as first diffraction light, and outputting the light reflected by the optical disc and diffracted by the second area as second diffraction light; a transmission light detection section for detecting the transmission light and outputting a TE1 signal indicating an offset of the detected transmission light; a first diffraction light detection section for detecting the first diffraction light and the second diffrac

Abstract: In an optical head, two object lenses 3a, 3b fixed to a lens holder 4 are provided to serve as means for condensing a light beam 11 wherein these object lenses 3a, 3b are at positions eccentric from a support axis 10. The object lenses 3a and 3b are fabricated to satisfy prescribed conditions to suppress aberration. When either object lens 3a or 3b is selected for an optical recording medium 17, 18, degrading of signals can be prevented. Alternatively, two light sources 14, 25 are provided for one object lens 19, and the object lens is fabricated to satisfy prescribed conditions to suppress aberration. When either one of the light sources is used, degrading of signals can be prevented. In a different optical head, a recording medium 107 is set on a disk driving device 111, and an optical head 115 is provided movable freely in radial directions. The tilt of the recording medium is detected with a sensor, and the optical axis of the beam is controlled according to the detected tilt to cancel aberration.

Abstract: An optical pickup has

Abstract: In a CIRC encoder for carrying out error correction coding processing with a CIRC, a first interleaver and a second interleaver are provided which have different delay parameters, and these interleavers are switched in accordance with the recording density of an optical disc for recording data. Also, in a CIRC decoder, a first deinterleaver corresponding to the first interleaver and a second deinterleaver corresponding to the second interleaver are provided, and these deinterleavers are switched in accordance with the recording density of an optical disc for reproducing data. A recording/reproducing system is realized which is capable of carrying out appropriate recording and reproduction of data to and from an optical disc having a higher recording density can be carried out and is also capable of handling an optical disc of an existing format.

Abstract: A laser light beam is illuminated via an objective lens on the signal surface of an optical disc and the objective lens is displaced by a servo processor along the optical axis for focussing search to generate focussing error signals by a RF block from a detected output of the laser light by the signal surface of the optical disc. Based on these focussing error signals, a system controller discriminates the types of the optical disc having different numbers of signal recording layers for setting an operating mode in keeping with the types of the optical disc.

Abstract: The present invention provides a disc drive apparatus which identifies a type of a disc mounted on the apparatus by using reflected beam data obtained from a laser beam focused on the disc surface and other reflected beam data obtained from the laser beam being focused on the disc signal plane. For example, while forcibly changing the laser beam focusing point within a variable range at a predetermined velocity, a luminous energy signal or a focus error signal is used to count a time difference between a timing of focusing on the disc surface and a timing of focusing on the disc signal plane. According to the time difference obtained, the disc mounted is identified as a first type of disc or a second type of disc.

Abstract: An optical head device of the present invention includes: a semiconductor laser for emitting a light beam; a first optical element for converting the light beam emitted from the semiconductor laser into collimated light having an elliptic beam shape; shaping means for shaping the beam shape of the collimated light from an ellipse to a circle; and a second optical element for directing the collimated light having the beam shape which has been shaped into a circle onto an optical information recording medium. The semiconductor laser is located so that a short axis direction of the ellipse is substantially parallel to a rotation axis direction of the optical information recording medium.

Abstract: A semiconductor laser device is comprised of a first lead member having a mounting portion for mounting a semiconductor laser, at least one second lead member to be connected to the semiconductor laser, and a resin mold member for unitarily molding the first and second lead members, wherein the resin mold member has a recess portion for receiving the semiconductor laser therein and for exposing therein the mounting portion of the first lead member and a part of the second lead member, and wherein the semiconductor laser is electrically connected to the first and second lead members within the recess portion.

Abstract: An optical pickup device is disclosed in which a light beam from a laser light source is converged by an object lens on a signal recording surface of an optical disk to follow recording tracks formed on the signal recording surface to read out or write data on or from the signal recording surface. A semiconductor laser unit is used as a laser light source and is so arranged that the meridional plane of the light beam emanating from the semiconductor laser unit is inclined 30.degree. to 60.degree. with respect to the tangential direction of the recording track.

Abstract: A method for manufacturing a hybrid integrated circuit device comprising a step of forming an Al.sub.2 O.sub.3 layer on a metal substrate, a step of forming on the Al.sub.2 O.sub.3 layer a resist layer having a pattern opposite to that of a copper layer which will be formed on the Al.sub.2 O.sub.3 layer by a later step, a step of forming the copper layer on the Al.sub.2 O.sub.3 layer using the resist layer as a mask, a step of impregnating thermosetting material into both the Al.sub.2 O.sub.3 layer and the copper layer, and a step of providing at least one semiconductor element on the copper layer.