FI923636A0 - OPTICAL SCANNING. - Google Patents

OPTICAL SCANNING.

Info

Publication number
FI923636A0
FI923636A0 FI923636A FI923636A FI923636A0 FI 923636 A0 FI923636 A0 FI 923636A0 FI 923636 A FI923636 A FI 923636A FI 923636 A FI923636 A FI 923636A FI 923636 A0 FI923636 A0 FI 923636A0
Authority
FI
Finland
Prior art keywords
objective lens
motion
lens
cylindrical lens
mutually perpendicular
Prior art date
Application number
FI923636A
Other languages
Finnish (fi)
Other versions
FI923636A (en
Inventor
Christian Buechler
Yasuaki S Morimoto
Original Assignee
Thomson Brandt Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thomson Brandt Gmbh filed Critical Thomson Brandt Gmbh
Publication of FI923636A publication Critical patent/FI923636A/en
Publication of FI923636A0 publication Critical patent/FI923636A0/en

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0908—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for focusing only
    • G11B7/0909—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for focusing only by astigmatic methods
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1365—Separate or integrated refractive elements, e.g. wave plates
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1372—Lenses
    • G11B7/1378—Separate aberration correction lenses; Cylindrical lenses to generate astigmatism; Beam expanders

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Head (AREA)
  • Optical Recording Or Reproduction (AREA)
  • Vehicle Body Suspensions (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Optical Communication System (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)
  • Microscoopes, Condenser (AREA)
  • Holo Graphy (AREA)

Abstract

In an optical scanning device, a light beam (L) is focused astigmatically by an objective lens (O) on a record carrier, e.g. a disk (CD), which reflects it onto a four-quadrant photodetector (PD). The astigmatism is produced by an astigmatic element, e.g., a concave or convex cylindrical lens (ZX) or two mutually perpendicular transparent disks located in the beam path. The light beam (L) can be moved radially by a coarse drive. The objective lens (O) can also be moved radially by a fine drive in a direction (W) which makes an angle $g(a) to the normals (R) to the data tracks (S). However, the movement of the objective lens (O) controlled by the fine drive through the angle $g(a) causes imaging defects on the four-quadrant photodector (A, B, C, D), which lead to faulty focusing. To prevent faulty focusing due to imaging defects, a preferred axis of the astigmatic element, e.g., a cylindrical lens or two mutually perpendicular transparent disks, runs parallel to the direction of movement (W) of the objective lens. In the case of a convex cylindrical lens (ZX), the longitudinal axis (LA) is parallel to the direction of motion (W) of the objective lens. In the case of a concave cylindrical lens, the transverse axis is parallel to the direction of motion (W) of the objective lens. In the case of two mutually perpendicular transparent disks, the straight line SG which intersects the two disks is perpendicular to the direction of motion (W) of the objective lens. CD players, video disk players, DRAW disk players, and magneto-optical devices.
FI923636A 1990-02-16 1992-08-14 OPTICAL SCANNING. FI923636A0 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4004858A DE4004858A1 (en) 1990-02-16 1990-02-16 OPTICAL SCANNER
PCT/EP1991/000226 WO1991012609A1 (en) 1990-02-16 1991-02-06 Optical scanning device

Publications (2)

Publication Number Publication Date
FI923636A FI923636A (en) 1992-08-14
FI923636A0 true FI923636A0 (en) 1992-08-14

Family

ID=6400308

Family Applications (1)

Application Number Title Priority Date Filing Date
FI923636A FI923636A0 (en) 1990-02-16 1992-08-14 OPTICAL SCANNING.

Country Status (11)

Country Link
EP (1) EP0515422B1 (en)
JP (1) JP2930137B2 (en)
CN (1) CN1023920C (en)
AT (1) ATE110875T1 (en)
AU (1) AU7215791A (en)
DE (2) DE4004858A1 (en)
ES (1) ES2063491T3 (en)
FI (1) FI923636A0 (en)
HK (1) HK113395A (en)
HU (1) HUT62419A (en)
WO (1) WO1991012609A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3191200B2 (en) * 1994-11-10 2001-07-23 コニカ株式会社 Recording / reproducing device for optical information recording medium
US5675686A (en) * 1995-07-05 1997-10-07 W. L. Gore & Associates, Inc. Buffer material for optical signal transmission media
JP2001034999A (en) * 1999-05-14 2001-02-09 Fujitsu Ltd Optical information storage and optical element
CN101049720B (en) * 2006-04-05 2010-09-01 鸿富锦精密工业（深圳）有限公司 Sensor for alignment of mould core, sensing method, and mould composition of possessing the sensor for alignment
CN107064563B (en) * 2017-03-29 2020-06-23 中国科学院苏州纳米技术与纳米仿生研究所 Light path damping device and method based on scanning probe

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6038771B2 (en) * 1978-06-19 1985-09-03 パイオニア株式会社 Servo device for optical information reading device
JPS5971141A (en) * 1982-10-14 1984-04-21 Mitsubishi Electric Corp Optical signal readout device
JPH01130332A (en) * 1987-11-17 1989-05-23 Toshiba Corp Focal point control device

Also Published As

Publication number Publication date
FI923636A (en) 1992-08-14
JP2930137B2 (en) 1999-08-03
JPH05504224A (en) 1993-07-01
CN1023920C (en) 1994-03-02
DE4004858A1 (en) 1991-08-22
DE59102748D1 (en) 1994-10-06
ATE110875T1 (en) 1994-09-15
CN1054848A (en) 1991-09-25
HUT62419A (en) 1993-04-28
EP0515422A1 (en) 1992-12-02
ES2063491T3 (en) 1995-01-01
AU7215791A (en) 1991-09-03
HK113395A (en) 1995-07-21
WO1991012609A1 (en) 1991-08-22
EP0515422B1 (en) 1994-08-31

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Legal Events

Date Code Title Description
FD Application lapsed