Sony Corporation

Chiaki Nonaka

Tadao Yoshida

Kazuhiko Fujiie

Masahiro Shigenobu

Makoto Yamada

Takashi Yoshida

Seiji Ohbi

Teruaki Higashihara

Hideo Kawachi

Hirohito Kawada

Hiroshi Arii

Yuichiro Hamada

Yoshiaki Haneda

Masanori Ohtawa

A reproducing apparatus for reading, or a recording apparatus for writing, data from or to a disc having pre-formed thereon a pair of concentrical or spiral tracks adjacent to each other and to which a common address is given, is adapted to control the time at which a read or write head is moved from one to the other of the pair of tracks or vice versa.

Recording apparatus and method, and reproducing apparatus and method

A modulation device and a demodulation device suitably performing DSV control while reducing the size and lowering the price of the hardware. Recording data is modulated at a modulator. In a DSV calculator, the DSV value of a modulated data is calculated in units of 1 DSV frame. A comparator outputs a sign comparison result of a DSV value cumulatively added from the start of recording and a DSV value to a DSV control bit insertion unit. The DSV control bit insertion unit inserts bits of DSV control data in accordance with the comparison result at a predetermined insertion position of the modulated data delayed by exactly an amount of 1 DSV frame. Thereafter, the modulated data is subjected to NRZ modulation.

Modulation device and demodulation device and methods of the same

Edges on both sides of each groove on a disk 11 are wobbled to indicate the addresses of recording locations. A laser beam for detection of data is radiated to a land for recording data, forming a spot 51-1. Two laser beams for detection of a tracking error are radiated to edges on both sides of a groove in such a way that the middle between the two laser beams coincides with the center of the groove, forming spots 51-2 and 51-3. By using such a tracking-error detecting laser beam to read out address information, the laser beam can be radiated to only the edge on a predetermined side of a groove. As a result, an address can be read out with a reduced amount of crosstalk from another groove even if the track pitch is small. Address information is thus read out with a highly accurate degree even in the case of a small track pitch.

Recording medium, address recording method and apparatus, and

A tracking servo signal is generated for use in an optical disc pick-up system, being particularly advantageous for use when the depth of the pits is greater or less than one-fourth the wavelength of the light beam used to read the disc, in which case diffraction patterns formed by reflected light beams are not symmetric on a photo-detector and typically result in DC-shifted tracking error signals. A first tracking error signal is generated from selected output signals of a number of light-receiving areas of the photo-detector and a second tracking error signal is generated by combining output signals from these light-receiving areas in a pattern different than that used in generating the first tracking error signal. These two tracking error signals are combined so that the resultant signal forms a tracking servo signal that has substantially no DC component.

Apparatus for generating tracking error signals in a differential phase

An apparatus for reproducing information signals recorded in spiral or coaxial tracks of a record disc includes a pick-up device operative, upon scanning of a track of the disc while the latter is rotated, to reproduce the information signals recorded in the scanned track; a driver for rotating the record disc relative to the pick-up device; a tracking device for controlling the tracing of the tracks by the pick-up device; a transporting device for bodily moving the pick-up device in a radial direction in respect to the axis of rotation of the record disc and thereby normally determining the tracks to be scanned by the pick-up device; and a controller selectively operative for causing the pick-up device to intermittently trace nonadjacent groups of tracks so as to intermittently reproduce the information signal recorded in the nonadjacent groups of tracks, respectively.

Disc player

In an apparatus for reproducing digitized signals recorded in successive, substantially circular tracks on a rotated disc by means of a pickup of the optical type which, in a normal scanning state, scans the tracks in succession; a first or prepare-to-play command signal causes the pickup to reproduce the digitized signals for a predetermined interval corresponding to more than one of the tracks on the disc starting from a desired position on such one track and the digitized signals reproduced in that predetermined interval are stored, desirably in a random access memory (RAM), whereupon a standby state of the pickup is established in which the pickup traces a closed loop on the rotated disc within a range corresponding to the previously mentioned predetermined interval. Upon reception of a second or play command signal, the pickup is released from its standby state at the completion of the tracing of the closed loop during which the play command signal occurred and the normal scanning state of the pickup is reestablished. Further, in response to the second or play command signal, the stored digitized signals are read out from the RAM and transmitted, starting with the signals corresponding to the desired position irrespective of the rotational position of the disc at the time of the play command signal, and the digitized signals reproduced by the pickup on the reestablishment of its normal scanning state and, more particularly, commencing with the digitized signals following the predetermined interval, are sequentially stored in the RAM and then sequentially read out and transmitted therefrom.

Disc reproducing apparatus

An apparatus for playing information recorded on a disc in substantially circular tracks on the latter includes a device for rotating the disc; a pickup for reproducing the information recorded on the disc; a tracking control circuit for adjusting the tracking position of the pickup in forward and reverse transverse directions with respect to the tracks; and a circuit operative through the tracking control circuit for selectively establishing a slow-playback mode and a reverse slow-playback mode in each of which, after the pickup reproduces a respective first predetermined number of the tracks while moving in the forward transverse direction, the tracking position of the pickup is moved in the reverse transverse direction a respective second predetermined integral number of tracks, the second predetermined number of tracks being less than twice the first predetermined number of tracks.

Digital audio disc player including apparatus for finding the beginning

An optical reproducing apparatus includes an optical pickup device which projects a laser beam onto a record disc having an information signal recorded in a plurality of record tracks thereon and which reproduces the information signal from the modulated laser beam reflected from the record disc, the optical pickup device including an objective lens movable in directions toward and away from the record disc to focus the projected laser beam onto the record disc; a focus servo control arrangement which moves the objective lens in the directions toward and away from the record disc in response to a focusing error signal which, in turn, is produced in response to the modulated laser beam, so as to focus the projected laser beam onto the record disc; a laser beam tracking device which rapidly moves the laser beam projected onto the record disc, during a search mode of operation, in a direction transverse to the record tracks to a desired position with respect to the record disc; a track jump signal generating circuit which produces a track jump signal in response to a track jump command signal to control the laser beam tracking device to rapidly move the projected laser beam to the desired position; and a current divider circuit which reduces the level of the focusing error signal, at least during the duration of the track jump signal, in response to the track jump command signal.

Apparatus for optically reproducing an information signal recorded on a

In an optical disc player for optically reading information recorded in substantially parallel tracks on the surface of a rotated record disc, an optical pick-up device includes an objective lens through which a light beam is to be focused at the surface of the record disc, and such device is shiftable, as a unit, in a radial direction of the record disc for determining the track to be scanned by the focused beam, a focusing servo control is responsive to defocusing of the light beam at the record disc surface for moving the objective lens in the direction to restore correct focus of the light beam at the record disc surface, and a gain control is provided for reducing the gain with which the focusing servo control responds to defocusing when the focused beam moves transversely across a plurality of the tracks on the record disc, for example, in the searching or random access mode of operation of the player, whereby to reduce vibratory movements of the objective lens and an undesirably harsh noise that would otherwise result from the defocusing incident to relatively rapid transverse movement of the focused beam across a number of the tracks.

Optical disc player with focus control during search mode

In a cooling assembly including a heat conductive block mounting an electronic part, and a heat pipe attached to the heat conductive block, a connector connected to the leads of the electronic part is arranged in the heat conductive block.

Growing community of inventors

Kanagawa, Japan

Chiaki Nonaka