公开(公告)号：JPH05234093A

公开(公告)日：1993-09-10

申请号：JP6101492

申请日：1992-02-18

Applicant: SONY CORP

Inventor： UDAGAWA TOSHIKI

IPC: G11B7/085

Abstract: PURPOSE:To limit a scanning range to some extent and to shorten a scanning operation time by moving in advance an objective lens to a target value, at the time of focusing scan. CONSTITUTION:When an operating command is received from an integrated controller, a disk jump control part 11 gives a command and an address to a target value holding part 12 and switches a switch 14, and switches a switch 13 by another controller. To one disk, a signal FS is generated from a focusing signal generator 10 and a lens is moved. By a leading-in range detector 9, a possible range is detected, and recorded in a RAM 12a through the switch 13 at the time of focusing. To the other disk, the range is recorded in a RAM 12b in the same way. On the other hand, when a disk jump is executed in the course of reproduction, the control part 11 switches the switch 14, and for instance, reads out a target value SM from the RAM 12b and holds it, supplies it to an actuator driver 6, and a lens is moved into a leading-in possible range. A focusing servo loop is formed, a servo operation based on a focusing error signal is executed, and the time required for a focusing servo start operation is shortened.

公开(公告)号：JPH04364254A

公开(公告)日：1992-12-16

申请号：JP29971091

申请日：1991-10-19

Applicant: SONY CORP

Inventor： FUKUMOTO ATSUSHI ,  UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI ,  ONO MASUMI ,  YASUDA KOICHI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To enhance a recording capacity of a medium by reducing a cross talk from an adjacent track and making narrow a track pitch by using a semiconductor laser as a laser beam source and making the minor axis direction of a spot form of exit light from the semiconductor to the direction being orthogonally crossed to the laser scanning direction. CONSTITUTION:A spot form of laser beams emitted from an active layer 22 of the semiconductor laser 21 forms an ellipse form being the direction parallel to the layer as the minor axis and being the depth direction of the layer as the major axis. The minor axis b direction of an ellipse form of a spot SP on the optical recording medium of the exit light from the laser 21 is made the direction being orthogonally crossed to the laser scanning direction. Hence the intensity of laser light radiating a record bit of the adjacent track is decreased, so the transfer of the signal being recorded and held at the adjacent track position is reduced for example in a magneto-optical recording medium of an erase type or an erase and raise mixing type, the cross talk is eliminated and the density is high since the track pitch is close.

公开(公告)号：JPH0479038A

公开(公告)日：1992-03-12

申请号：JP19037990

申请日：1990-07-20

Applicant: SONY CORP

Inventor： YOSHIMURA SHUNJI ,  UDAGAWA TOSHIKI ,  OTA MASUMI

IPC: G11B7/00 ,  G11B7/0045 ,  G11B7/125

Abstract: PURPOSE:To perform appropriate recording even when recording density is high by controlling the light emitting power of a light source in accordance with a signal obtained by integrating recording pulse signals. CONSTITUTION:An output signal from a photodiode 6 is converted into a voltage signal and transmitted to a subtracter 14. A light emitting power detecting level is subtracted from a reference power setting level in the subtracter 14, and an error component between the reference power and the detected light emitting power is outputted as a power control signal from an LPF(low-pass filter) 16 and transmitted to a laser light source driving circuit 12, so that the light emitting power is controlled in a direction where the error of the power becomes small. Furthermore, by supplying the output signal obtained by integrating the recording pulse signals in the LPF 18 to the subtracter 17 and subtracting the integration output signal from the output signal from the LPF 16, the controlled variable of the laser light emitting power is corrected to perform correction for restraining the light quantity of light pulse when an interval between pulses is short. Thus, the appropriate recording is performed even in the case of high-density recording.

公开(公告)号：JPH035928A

公开(公告)日：1991-01-11

申请号：JP13999889

申请日：1989-06-01

Applicant: SONY CORP

Inventor： OSATO KIYOSHI ,  UDAGAWA TOSHIKI ,  OKADA HITOSHI

IPC: G11B7/095

Abstract: PURPOSE:To form a tracking error signal whose amplitude is not changed by obtaining the ratio of the difference between the detection outputs obtained from second and third light detection elements to the difference between the sum of the detection outputs obtained from the second and the third light detection elements and the detection output obtained from a first light detection element and forming the tracking error signal. CONSTITUTION:The tracking error signal is formed by obtaining the ratio of the difference between the detection output obtained from the second light detection element 58 and the detection output obtained from the third light detection element 60 to the difference between the sum of the detection outputs obtained from the second and the third light detection elements 58 and 60 and the detection output obtained from the first light detection element 56. The tracking error signal obtained in such a way becomes the one having the almost fixed amplitude which is not changed according to the depth of a guide groove on a disk shaped recording medium where a light beam is made incident on, the depth of a pit or the height of a bump which forms a recording track, reflectance with respect to the light beam and the light quantity of the light beam which is made incident on the disk shaped recording medium, besides.

公开(公告)号：JPS63209035A

公开(公告)日：1988-08-30

申请号：JP4343287

申请日：1987-02-26

Applicant: SONY CORP

Inventor： UDAGAWA TOSHIKI ,  OKADA HITOSHI

IPC: G11B7/09

Abstract: PURPOSE:To attain accurate and stable control by obtaining the mean value of skew detection signals of a specified number of rotations and controlling based on the mean value. CONSTITUTION:A titled circuit has a skew detection means 100 for detecting the tilt of an optical disk 3, a mean value detection means 16A for obtaining the mean value of detection signals SER of the skew detection means 100 corresponding to at least one rotation of the optical disk 3 and control means 10P and 10N and 11-13 for controlling in order that the optical axis of the optical pick-up is made to be nearly orthogonally crossed with the disk surface of the optical disk 3 based on the output signal SER' from the mean value detection means 16A. When the mean value exceeds an allowable stagger angle, the optical axis of the optical pick-up is securely controlled to turn. And even if the pulse part is generated in the skew detection signal SER by some cause when the mean value is within the allowable stagger angle, the optical axis of the optical pick-up is not controlled to turn so that malfunction does not occur. Therefore, the accurate and stable control can be attained.

公开(公告)号：JP2002358641A

公开(公告)日：2002-12-13

申请号：JP2001158873

申请日：2001-05-28

Applicant: SONY CORP

Inventor： UDAGAWA TOSHIKI

IPC: G11B7/244 ,  G11B7/0045 ,  G11B7/1263 ,  G11B7/125 ,  G11B7/24

Abstract: PROBLEM TO BE SOLVED: To obtain an optimum recording laser power condition in real time corresponding to the environmental condition related to mark formation. SOLUTION: At the time of data recording operation (formation of mark and space) performed by applying a pulse train-like laser output to a recording medium of organic coloring material, a space period signal value corresponding to the space period in a reflected light information signal is detected, and a leading pulse signal value corresponding to the leading pulse in the pulse train like laser output is estimated. Also, a signal value after 2nd pulse corresponding to after 2nd pulse in the pulse train-like laser output is detected in the reflected light information. Then, the ratio between the estimated leading pulse signal value and the detected signal value after 2nd pulse is obtained, and by using the obtained value of ratio and the referenced value of ratio, a laser power correcting signal is produced to control the laser output power.

公开(公告)号：JPH10239577A

公开(公告)日：1998-09-11

申请号：JP4446897

申请日：1997-02-27

Applicant: SONY CORP

Inventor： SAKAMOTO SATOSHI ,  SUZUKI JUNICHI ,  UDAGAWA TOSHIKI ,  YAMAZAKI MICHIKO

IPC: G02B7/04 ,  F16C29/02 ,  G02B7/08

Abstract: PROBLEM TO BE SOLVED: To hold a slide mechanism part without exciting it. SOLUTION: A shaft 1 is provided with a groove 1A and a groove 1B perpendicularly to the axial direction. The groove 1A and the groove 1B are formed into a V-shape on the first face 1a and the second face 1b, and the third face 1c and the fourth face 1d, respectively. The angle between the second face 1b and the axial direction of the shaft 1 is made smaller, than the angle between the first face 1a and the axial direction, and the angle between the third face 1c and the axial direction is made smaller than the angle between the fourth face 1d and the axial direction. This slide mechanism part 5 holds a spherical body 2 with a spherical body hold section 4, and it is moved along the shaft 1 while the spherical body 2 is pressed to the shaft 1 by a spring 3. When the spherical body 2 is coupled in the groove 1A or groove 1B, the slide mechanism part 5 is positioned and maintained at its position.

公开(公告)号：JPH09147394A

公开(公告)日：1997-06-06

申请号：JP32795595

申请日：1995-11-22

Applicant: SONY CORP

Inventor： UDAGAWA TOSHIKI

IPC: G11B7/095

Abstract: PROBLEM TO BE SOLVED: To easily detect a tangential skew quantity with a simplified constitution by detecting the displacement of the optical axis direction of a focus actuator and performing a conversion from the displacement into the tangential skew quantity. SOLUTION: A focus actuator driving signal S1 to be outputted from a focus servo circuit 21 is inputted to a filter circuit 24 reproducing the transfer characteristic of the focus actuator and then the wobbling quantity of a disk is obtained. The wobbling quantity is sampled 26 by the pulse signal from a pulse generating circuit 32 based on a disk rotational synchronizing signal 31. The tangential skew quantity being the change of wobbling quantities is obtained by comparing data of adjacent areas with respect to N pieces of disk areas every one revolution of the disk by a difference detecting means 27. Then, a tangential skew error signal concerning to a unit time is obtained by an adjustment circuit 30.

公开(公告)号：JPH0636328A

公开(公告)日：1994-02-10

申请号：JP21543592

申请日：1992-07-21

Applicant: SONY CORP

Inventor： UDAGAWA TOSHIKI

IPC: G11B7/125

Abstract: PURPOSE:To quickly stabilize the servo by automatically controlling the ambient temperature of a light source to set the intensity of light to a prescribed value at the time of arrival of the temperature of the light source at a preliminarily set prescribed reference temperature. CONSTITUTION:A thermistor 3 detects the temperature of an LD block 31, and exciting laser light is made incident on a lens block, and micro green laser SBG light is generated. This SHG light is made incident on an optical axis changing block and is turned from the direction parallel with an optical base to the direction perpendicular to it and is thrown to an optical disk. An APC and ATC servo loop on/off timing controller 16 compares an environmental temperature Te detected by an environmental temperature detector 43 with a set temperature To outputted from a set temperature generating circuit 18. The controller 16 performs a prescribed operation in accordance with the comparison result to approximate the temperatures Te and To to each other. When the temperature Te arrives at the prescribed reference temperature To, the ATC operation is started to set the environmental temperature Te to a prescribed temperature. Thus, the ATC servo is quickly stabilized.

公开(公告)号：JPH04258831A

公开(公告)日：1992-09-14

申请号：JP4098791

申请日：1991-02-12

Applicant: SONY CORP

Inventor： FUKUMOTO ATSUSHI ,  UDAGAWA TOSHIKI ,  YOSHIMURA SHUNJI

IPC: G11B7/125 ,  G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To prevent the change of a substantial reproducing area caused by the change of temperature and linear velocity of a magneto-optical disk in a novel reproducing method for magneto-optical disk of erase type or raise-out type. CONSTITUTION:The reference information which is being recorded in the magneto-optical disk 31, is reproduced prior to the substantial data reproduction, and this reproduced RF signal level is detected, then a laser power and external magnetic field are controlled so that this level becomes an optimum level for reproduction to make the substantial reproducing area always optimum and constant. At the actual reproducing time, the control is made so as to keep the states of laser power and external magnetic field constant.