| Patent Number |
Title Of Patent |
Date Issued |
| 6980496 |
Information recording/reproducing apparatus |
December 27, 2005 |
| An information recording/reproducing apparatus includes an optical device, a photo-detector and a calculation unit. The optical device irradiates light beams, including one main beam and at least two sub-beams with respect to an information recording medium. The photo-detector receives |
| 6894955 |
Quick access information read and write devices |
May 17, 2005 |
| There are provided an information write device and an information read device enabling to generate highly accurate contrast signals. When a main light spot Pc is located at the center of the a groove G, the light spot Pc and sub light spots Psa, Psb are each adapted to radiate a disc DSC |
| 6346695 |
Optical pickup device |
February 12, 2002 |
| A light beam is emitted by a light source, and an optical system separates the light beam into a main-portion and a sub-portion. The main-portion of the light beam is guided to an information storage medium. A monitor detector receives the sub-portion of the light beam and outputs a |
| 6339581 |
Disc player having a prepit detecting circuit |
January 15, 2002 |
| A disc player having a prepit detecting circuit which can correctly detect prepits even if phases or amplitude levels of a plurality of read signals read out from a recording disc are deviated from each other. A phase difference between a first read signal and a second read signal read o |
| 6317400 |
Optical pickup apparatus |
November 13, 2001 |
| An optical pickup apparatus is provided with: a light source (20) for emitting a light beam; an optical system (21, 22, 24, 25, 26, 27), which comprises an optical element (24) having an incident surface (24a), to which an AR (Anti-Reflection) coat is not applied and to which the light |
| 6282067 |
Magnetic reproducing head having a magnetoresistive effect |
August 28, 2001 |
| A magnetoresistive effect element 5 is physically configured such that the element width is at least three times as large as the element height. A plurality of domain control layers 11 to 13 are located between the magnetoresistive effect element 5 and a plurality of detecting electrodes |
| 6072651 |
Information recording/reproducing apparatus for reproducing information without requiring tracki |
June 6, 2000 |
| An information recording/reproducing apparatus capable of correctly reproducing information from a large number of recording tracks without requiring tracking servo. A recording medium is formed with at least one pilot track on which a pilot signal is recorded and a plurality of info |
| 5708636 |
Tracking error signal generation device |
January 13, 1998 |
| A tracking error signal generation device is used for an optical pickup device capable of reproducing and/or recording an information signal on a spiral or coaxial signal track of a disk shaped optical record medium of one type among a plurality of optical record media of different types |
| 5339302 |
RF signal-compensated system for reading an optical disc player with an absolute time detector |
August 16, 1994 |
| A reading system of an optical disc has a pregroove having a wobbled inside wall and pits for representing recorded data, and a pair of photodetector elements for detecting a spot of a laser beam reflected on the optical disc. The wobbled inside wall is modulated so as to represent absol |
| 5172355 |
Photo-detecting device including offset correction |
December 15, 1992 |
| 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 |
| 5150342 |
Photo-detecting device |
September 22, 1992 |
| 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 |
| 5136567 |
Photo-detecting device |
August 4, 1992 |
| The light receiving surface of the light receiving element, which receives reflected light from an information recorded disc, is divided into sections along lines passing through the center of the surface which run parallel to and perpendicular to the direction of tracking and which also |
| 5003411 |
Method for recording/reproducing and searching digital signals using a helical scan type rotary |
March 26, 1991 |
| A method for performing a reproduction and search operation on a data recording and reproducing device of the helical scan type which includes a pair of recording and reproducing heads mounted on a rotary drum. The method includes the steps of: (a) during the reproduction operation, |
| 4930031 |
Apparatus for recording and reproducing digital signals using a helical scan |
May 29, 1990 |
| An apparatus for recording and reproducing digital signals using a helical scan in which a drum of reduced diameter is employed without changing the tape format. Two heads are mounted on a drum at the same height in opposition to each other with a product of the diameter D of the drum an |
