Matsushita Electric Industrial Co., Ltd.

Yukinori Okazaki

Ryoichi Imanaka

Yoshimitsu Nakamura

Makoto Usui

Toshihiko Takahashi

Nobuyuki Nakamura

Ichiro Kawamura

Toshiya Akagi

Yoshio Umeda

Makoto Fujita

Goro Naoki

Mieko Kobukata

An information recording/reproducing device and a medium are improved in reliability by making medium managing information usable even when a defective sector exists in the medium managing information area of the medium. The identifier of medium managing information, the information about the position where the medium managing information is recorded which is the information about the position of the sector in use, or the information about the position where a defect exists in the medium managing information area, which is the information about the position of the defective sector, are read from the medium managing area of the medium (,) and all the information is stored in a RAM (,) by using a medium managing information position manager. A reproducer and a recorder are controlled based on the information. Therefore, the medium managing information is correctly recorded and the reliability of the data of the information recording/reproducing device and the medium is improved, because the medium managing information is not recorded in the defective section.

Information recording/reproducing unit and information recording/reproducing data

A random data recording area and a serial data recording area are placed in a radial direction on the same surface of a zoned constant angular velocity disk. The random data recording area is located at an inner circumference of the disk, while the serial data recording area is located at an outer circumference of the disk. The random data recording area consists of a rewritable random data recording area and a read-only random data recording area, wherein the read-only random data recording area is placed at an inner circumference of the disk. The serial data recording area consists of a rewritable serial data recording area and a read-only serial data recording area, wherein the read-only serial data recording area is placed at an outer circumference of the disk.

Optical recording medium having both serial data and random data

In an automatic medium changing apparatus capable of storing a multiplicity of optical disks, the control parameters required for the drive control system of a drive unit for recording-reproducing are automatically regulated for all the combinations of the existing drive units and all the media held. The resulting values of the control parameters are stored in a control unit of the automatic medium changing apparatus and the apparatus is controlled by the corresponding control parameters transferred from the control unit at the time of processing the medium.

Automatic medium changing apparatus using an automatic regulator

A disk nearly constant in recording density from the outer circumference to the inner circumference of the disk, such as CLV and M-CAV format, is rotated at a constant angular velocity to read out information, and the information being read in at a varying read transfer speed depending on the position on the disk from the optical pickup is stored once in a buffer memory. The information stored in the buffer memory is sent out at a constant send transfer speed. When reproducing from a disk-shaped recording medium nearly constant in recording density in the inner and outer circumference, the disk information is read at a constant rotating angular velocity, and the information varying in read transfer speed depending on the disk position is outputted at a constant send transfer speed suited to the reproduction of information such as voice and picture. The host computer or the like for controlling the apparatus is not required to distinguish the type of medium or recording format, or perform processing such as control of the transfer speed. Furthermore, when outputting the stored information, means for setting the send transfer speed by an external device or switch inside the apparatus is provided. By this means, the information can be reproduced at a transfer speed suited to the content of the information being handled.

Disk information reading control apparatus having a variable read

An information recording apparatus includes a laser source emitting a laser beam for reproducing or recording data pits on a recording medium; an objective lens; a photodetector; an analog signal processing means performing amplification and waveform shaping for an electric signal output from the photodetector; a land/groove detecting means and outputting a polarity switch instruction signal; a reproduction signal polarity switch means for changing the signal polarity at reproduction in response to the polarity switch instruction signal from the land/groove detecting means; a controller for controlling the information recording apparatus at the request of a host computer performing control and process as a whole; a recording pulse modulating means for modulating a recording pulse on the instruction from the controller; a polarity switch means for changing the polarity of an output from the recording pulse modulating means; a recording signal polarity switch means for changing the signal polarity at recording in response to the polarity switch instruction signal from the land/groove detecting means by selecting one of an output from the polarity switch means and an output from the recording pulse modulating means, and outputting a recording data signal; and a laser driving means for controlling the laser source in response to the recording data signal from the recording signal polarity switch means, whereby the recording polarity of the data pits is switch between adjacent tracks on the recording medium, resulting in recording and reproduction of signals which are hardly affected by crosstalk between the adjacent tracks.

Optical disk data recording and reproduction with opposed polarity in

In an magneto-optic disk apparatus which carries out recording, playback, or erasing of data with a single laser beam, recorded data is read simultaneously with a recording or erasing operation to eliminate the time of waiting for the disk to make a turn. A signal separation circuit 7 is provided for a magneto-optic disk apparatus which carries out recording, playback, erasing of data by applying a laser beam through an optical head 2 to a spot on a magneto-optic disk 3. In a recording or erasing operation, a magneto-optic playback signal 6 obtained from reflected light of a recording or erasing beam is input to the signal separation circuit 7 to separate and output the recorded data signal 8 contained in the magneto-optic playback signal 6 to consequently reading a recorded data signal 10 simultaneously with carrying out a recording or erasing operation.

Magneto-optic disk apparatus

In a magneto-optic memory device for recording information on a magneto-optic recording medium having a magneto-optic recording film irradiated by a first small diameter light spot and a second larger diameter light spot which is substantially concentric with the first light spot, the temperature of a portion of the recording film around a recording position is changed by the irradiation of the second light spot in accordance with an information signal to be recorded, between a temperature, which is lower than a compensation temperature of the recording film and produces spontaneous magnetization of the recording film having intensity necessary for recording information, and a temperature which is higher than the compensation temperature of the recording film and produces spontaneous magnetization of the recording film having intensity necessary for recording information, and the intensity of the first light spot is increased to raise the temperature of the recording position of the recording film so as to reach near the Curie temperature of the recording film, thereby erasing old information and recording new information at the same time.

Magneto-optic memory device for overwriting information on magneto-optic

An optical disk provided with a ROM area for reproduction only, in which information for reproduction only and first retrieval information for retrieving the information for reproduction only are recorded in embossed shape and a rewritable area in which information can be additionally recoded or rewritten, wherein on the basis of each of a plurality of additionally recording and rewriting logical specifications of respective appliances utilizing the optical disk, the first retrieval information is converted into second retrieval information, wherein the second retrieval information corresponds to at least one of the appliances and is recorded in the rewritable area together with third retrieval information for the additionally recordable and rewritable information so as to be additionally recordable or rewritable, and an apparatus for recording and reproducing the optical disk.

Partial ROM type optical disk and its recording and reproducing apparatus

An apparatus for generating a bias magnetic field to a magneto-optical disk includes a movable magnet which serves to generate a bias magnetic field. A suitable device serves to generate a drive magnetic field to move the magnet. A stopper is engageable with the magnet to stop the magnet at a predetermined position.

Bias magnetic field generating apparatus for magneto-optical recording

The present invention generally relates to optical recording/reproducing apparatus, and relates particularly to a tracking system therefor. Tracking pit rows are provided on opposite sides of an information signal recording area. The frequencies of the tracking pit rows differ from each other, such that tracking servo normalizes a detected difference in amplitude between the reproduced signals of the tracking pit rows, resulting in improved tracking accuracy.

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Hirakata, Japan

Yukinori Okazaki