公开(公告)号：JPH08221790A

公开(公告)日：1996-08-30

申请号：JP2656295

申请日：1995-02-15

Applicant: SONY CORP

Inventor： MAEDA FUMISADA ,  ICHIMURA ISAO ,  YAMAMOTO KENJI ,  OSATO KIYOSHI ,  WATANABE TOSHIO

IPC: G11B7/12 ,  G11B7/135

Abstract: PURPOSE: To realize a high-density reproducing, to make the allowable value of warpage at the time of molding a disk and warpage caused by moisture absorption large, and to increase the yield in production and the degree of freedom in selecting disk material. CONSTITUTION: The surface of a semi-spherical lens 9 opposed to an optical disk 20 is a plane 9b, and the refractive index of the lens 9 is set to a specified value. A slider 12 fixes the lens 9 and slides on the optical disk 20. A leaf spring 13 presses and supports the slider 12 so as to slide on the optical disk 20.

公开(公告)号：JPH08221772A

公开(公告)日：1996-08-30

申请号：JP2656395

申请日：1995-02-15

Applicant: SONY CORP

Inventor： YAMAMOTO KENJI ,  MAEDA FUMISADA ,  ICHIMURA ISAO ,  OSATO KIYOSHI ,  WATANABE TOSHIO

IPC: G11B7/09 ,  G11B7/125 ,  G11B7/135 ,  G11B7/1374 ,  G11B7/1392

Abstract: PURPOSE: To realize a high density reproduction, to reduce the spherical aberration occurring on a signal recording surface of an optical recording medium and to enhance the reproducing characterstics. CONSTITUTION: A semispherical lens 7 is provided with a plane 7b confronted with a light incident surface 20a of an optical disk 20, and is a convex lens, a refractive index of which is set in a prescribed value. A converging optical system 23 converges reflected light from the light incident surface 20a and the plane 7b. A PD 15 detects the reflected light R2 from the plane 7b through the converging optical system 23. A PD 19 detects the reflected light from the plane 76 through the converging optical system 23. A subtracter 21 detects a positional relation between the light incident surface 20a and the plane 7b based on the detection output Pb of the PD 15 and the detection output Pc the PD 19. An actuator 31 for the semispherical lens drives the semispherical lens 7 in the direction of the optical disk 20 or an objective lens 6 so as to control the gap of an air layer AG between the light incident surface 20a and the plane 7b based on the output Pb -Pc of the substracter 21.

公开(公告)号：JPH05144056A

公开(公告)日：1993-06-11

申请号：JP33245191

申请日：1991-11-20

Applicant: SONY CORP

Inventor： OSATO KIYOSHI

IPC: G11B7/095

Abstract: PURPOSE:To raise the recording density and to surely record and reproduce recorded information by changing the impressed voltage of each area in accordance with the inclination of an optical disk to correct the coma aberration of a light beam on the information recording face. CONSTITUTION:Output signals S1A and S1B of a photodetector 26 are subjected to subtraction by a subtracting circuit 28 to detect the coma aberration on an optical disk 2, and the thickness of a wave surface correction plate 20 is corrected by drive voltages V1 to V3 generated by a correction voltage generating circuit 34 based on the detection result, and the coma aberration due to inclination of the optical disk is canceled by the wave surface aberration of the wave surface correction plate 20, and then, the occurrence of the coma aberration on an information recording face 6 is effectively avoided. Consequently, recorded information is surely reproduced even if the recording density is raised high.

公开(公告)号：JPH04350819A

公开(公告)日：1992-12-04

申请号：JP12623591

申请日：1991-05-29

Applicant: SONY CORP

Inventor： SOTOZAKI MINEHIRO ,  OSATO KIYOSHI ,  SUGANUMA HIROSHI

IPC: G02B26/06 ,  G02F1/00

Abstract: PURPOSE:To provide the variable phase plate which generates a phase difference with good reproducibility and good controllalility and can surely detect a focal position. CONSTITUTION:This variable phase plate is constituted by adhering an outer part 1 and inner part 2 consisting of light transmittable dielectric substances via an elastic material 3 so as to have elasticity. Light transmittable conductor layers 4S1 and 4S2, 4C1 and 4C2 are deposited discretely on at least one surface of the outer part 1 and the inner part 2 or commonly or discretely on the other surface. The thicknesses of the outer part 1 and inner part 2 are discretely changed by changing the voltages to be impressed to the conductor layers 4S1 and 4S2, 4C1 and 4C2, by which the phase difference is generated in the light passing the outer part 1 and the inner part 2.

公开(公告)号：JPH04345078A

公开(公告)日：1992-12-01

申请号：JP14692091

申请日：1991-05-22

Applicant: SONY CORP

Inventor： MASUDA HISASHI ,  OSATO KIYOSHI ,  FUKUMOTO ATSUSHI

IPC: G02F1/37 ,  H01S3/02 ,  H01S3/04 ,  H01S3/042 ,  H01S3/06 ,  H01S3/0941 ,  H01S3/101 ,  H01S3/109 ,  H01S3/131

Abstract: PURPOSE:To restrain the noise of a laser diode from appearing in the second harmonic wave laser light outputted from a laser optical resonator. CONSTITUTION:Laser light for pumping outputted from a laser diode 1 enters laser medium 5 via a lens 2. Thereby fundamental wave laser light is generated. When said laser light enters a nonlinear optical crystal element 6, the second harmonic wave laser light is generated. The leak component of the fundamental wave laser light is detected with a photodetector 22, and its output is compared with a reference voltage in a differential amplifier 23. The laser diode 1 is driven so as to correspond with the error signal.

公开(公告)号：JPH04219712A

公开(公告)日：1992-08-10

申请号：JP41233690

申请日：1990-12-20

Applicant: SONY CORP

Inventor： OSATO KIYOSHI

IPC: G02B26/10 ,  B41J2/44 ,  G03G15/04

Abstract: PURPOSE:To provide a spot position detecting device which enables correct detection of the spot position (scanning position) of the laser beam on the real time basis on a scanned surface when drawing is made by the laser beam. CONSTITUTION:The laser beam radiated from a laser diode 1 is reflected by galvano-mirrors 9, 10 which are polarized in the Y and X axis direction, and projected onto a scanned surface 13. On the other hand, the laser beam from a laser diode 4 which radiates the position-detecting laser beam is also projected onto a position-detecting mask 14 through the above-mentioned optical system, and the reflected laser beam from the position-detecting mask 14 is projected onto a photo-diode 17 which is divided into a plurality of pieces. The scanning position of the laser beam projected onto the scanned surface 13 is detected on the real time basis by executing the output from the respective divided photo-diodes 17 by the operation circuit.

公开(公告)号：JPH0438629A

公开(公告)日：1992-02-07

申请号：JP14252190

申请日：1990-05-31

Applicant: SONY CORP

Inventor： FUKUMOTO ATSUSHI ,  OSATO KIYOSHI

IPC: G11B7/095 ,  G11B7/09

Abstract: PURPOSE:To perform the tracking control of high-density recording tracks by generating (n) signals whose spatial phases are offset from one another by p/2n and multiplying these signals to obtain a tracking control signal where the space period is 1/n of a conventional track pitch (p). CONSTITUTION:An optical disk is irradiated with plural light beams from a laser beam source to form plural beam spots SPa and SPo offset from each other at every 1/2n of the track pitch (p) on this optical disk. Based on these beam spots, (n) signals Sso and Ssa whose spatial phases are offset from each other at every 1/2n of the track pitch are generated. These signals are multiplied to generate a tracking control signal ST2 whose space period is 1/n of the track pitch, and tracking control is performed based on this tracking control signal. Thus, the tracking control of the optical disk which has a high density exceeding the space cut-off frequency of this optical system is available.

公开(公告)号：JPH03100929A

公开(公告)日：1991-04-25

申请号：JP23560489

申请日：1989-09-13

Applicant: SONY CORP

Inventor： NARAHARA TATSUYA ,  KABAYA YOSHITERU ,  OSATO KIYOSHI ,  MIYOSHI HIROSHI

IPC: G11B7/09 ,  G11B7/003

Abstract: PURPOSE:To shorten a focusing and tracking lead-in period by setting a target value from a sample value at the point of time when an optical head rushes in a section where it faces to an optical tape and controlling the position of an actuator in the case that it rushes next. CONSTITUTION:At the point of time T1 when the optical head rushes in the A section where it faces to the optical tape, a focusing error signal ef1 and a position signal Sr1 are sampled by S/H circuits 27 and 28 based on a sampling pulse Ps. In a B(idly running) section, the actuator is controlled to be at a just-focusing position according to the target value generated from the held signals er1 and Sr1 when a switching circuit SW is connected to a b terminal with a switching pulse Psw. At the point of time T2 when it rushes in the A section next, the actuator is controlled to be at the just-focusing position at the point of time T1. Thus, focusing control is started from a lens position approximate to the just-focusing position and the lead-in action to the just- focusing position is achieved in a short time.

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：JPH035927A

公开(公告)日：1991-01-11

申请号：JP13999789

申请日：1989-06-01

Applicant: SONY CORP

Inventor： OSATO KIYOSHI

IPC: G11B7/095 ,  G11B7/09

Abstract: PURPOSE:To obtain a tracking error signal whose amplitude is not changed by obtaining the ratio of difference between the sum of a second difference output and a third difference output and a first difference output to the difference between the second difference output and the third difference output and forming the tracking error signal. CONSTITUTION:A main beam and two sub-beams are respectively detected by a first, a second and a third substantial two-split light detection elements 60, 62 and 64. Then, the first difference output being the difference between the detection outputs obtained by the respective first detection elements 60, the second difference output being the difference between the detection outputs obtained by the respective second detection elements 62 and the third difference output being the difference between the detection outputs obtained by the respective third elements 64 are obtained. Then, the tracking error signal is formed by obtaining the ratio of the difference between the sum of the second difference output and the third difference output and the first difference output to the difference between the second difference output and the third difference output. Thus, the tracking error signal having the amplitude which is almost fixed and which is not changed according to the light quantity of a light beam is obtained.