Radiant energy – Photocells; circuits and apparatus – Photocell controls its own optical systems
Patent
1992-06-23
1993-09-14
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Photocell controls its own optical systems
359638, 369 4412, G01J 126
Patent
active
052451747
ABSTRACT:
An apparatus for evaluation of radiation beam geometry that finds application in determining the focus of an illuminating beam relative to an optical disk is disclosed herein. In one preferred embodiment, a light source generates a linearly polarized beam which is collimated by a collimating lens. The collimated beam is then converged by an objective lens onto the surface of the optical disk. The disk reflects the illuminating beam focused thereon back through the objective lens to a beam splitter. A portion of the optical energy incident on the beam splitter is then redirected to form a servo beam, wherein the degree of collimation of the servo beam is indicative of the focus position of the illuminating beam. A beam separation module, based on frustrated total reflection, having a reflectivity which varies in response to the angle of incidence of optical energy thereon is positioned to intercept the servo beam. The beam separation module is operative to separate the servo beam into transmitted and reflected beams of substantially similar shape and intensity. Electrical signals produced by photodetective elements in response to incidence of the transmitted and reflected beams thereon may then be used to generate a focus error signal.
REFERENCES:
patent: 2240988 (1941-05-01), Hertel
patent: 2432432 (1947-12-01), MacNeille
patent: 3536375 (1990-10-01), Mansell
patent: 3652167 (1972-03-01), Smith
patent: 3677621 (1972-07-01), Smith
patent: 3844638 (1974-10-01), Lingenfelder et al.
patent: 3922069 (1975-11-01), Kishikawa et al.
patent: 3976828 (1976-08-01), Jansen
patent: 3992574 (1976-11-01), Bouwhuis et al.
patent: 4110011 (1978-08-01), Tausch
patent: 4123652 (1978-10-01), Bouwhuis
patent: 4253723 (1981-03-01), Kojima et al.
patent: 4334300 (1982-06-01), Arquie et al.
patent: 4358200 (1982-11-01), Heemskerk et al.
patent: 4399529 (1983-08-01), Leterme et al.
patent: 4411492 (1983-10-01), Bluege
patent: 4411500 (1983-10-01), Yonezawa et al.
patent: 4422168 (1983-12-01), Ito et al.
patent: 4423495 (1983-12-01), Musha
patent: 4423496 (1983-12-01), Opheij et al.
patent: 4425636 (1984-01-01), Musha
patent: 4441175 (1984-04-01), Shuman
patent: 4447722 (1984-05-01), Saimi
patent: 4449213 (1984-05-01), Noborimoto et al.
patent: 4450547 (1984-05-01), Nakamura et al.
patent: 4453239 (1984-06-01), Musha
patent: 4455085 (1984-06-01), Kato et al.
patent: 4458980 (1984-07-01), Ohki et al.
patent: 4475182 (1984-10-01), Hosaka
patent: 4489408 (1985-09-01), Verhoeven et al.
patent: 4497534 (1985-02-01), Sincerbox
patent: 4502783 (1985-03-01), Lau et al.
patent: 4504935 (1985-03-01), Jansen
patent: 4504938 (1985-03-01), Tajima
patent: 4507766 (1985-03-01), Saimi et al.
patent: 4514837 (1985-04-01), Van Rosmalen
patent: 4525625 (1985-06-01), Abe
patent: 4542492 (1985-09-01), Leterme et al.
patent: 4577941 (1986-03-01), Kubota
patent: 4587644 (1986-05-01), Fujjie
patent: 4596444 (1986-06-01), Ushida
patent: 4611317 (1986-09-01), Takeuchi et al.
patent: 4612437 (1986-09-01), Ohsato
patent: 4614863 (1986-09-01), Sato
patent: 4624526 (1986-11-01), Tsukai et al.
patent: 4641926 (1987-02-01), Shirasaki
patent: 4644516 (1987-02-01), Musha
patent: 4669073 (1987-05-01), Wakabayashi et al.
patent: 4669823 (1987-06-01), Iguma et al.
patent: 4689481 (1987-08-01), Ono
patent: 4689779 (1987-08-01), Hayashi et al.
patent: 4691098 (1987-09-01), Maeda
patent: 4694447 (1987-09-01), Cohen et al.
patent: 4701603 (1987-10-01), Dakin et al.
patent: 4707648 (1987-11-01), Minami
patent: 4707817 (1987-11-01), Yoshio
patent: 4716559 (1987-12-01), Hine
patent: 4730294 (1988-03-01), Funada
patent: 4730295 (1988-03-01), Bressers
patent: 4733065 (1988-03-01), Hoshi et al.
patent: 4740946 (1988-04-01), Yumara et al.
patent: 4763314 (1988-08-01), MacCaslin et al.
patent: 4794586 (1988-12-01), Korth
patent: 4797868 (1989-01-01), Ando
patent: 4819220 (1989-04-01), Myazaki et al.
patent: 4823335 (1989-04-01), Shikama et al.
patent: 4823336 (1989-04-01), Inada et al.
patent: 4862442 (1989-08-01), Tadokoro
patent: 4876680 (1989-10-01), Misawa et al.
patent: 4890273 (1989-12-01), Takeuchi et al.
patent: 4891798 (1990-01-01), Shinikai
patent: 4899327 (1990-02-01), Bates et al.
patent: 4911534 (1990-03-01), Henegouwen et al.
patent: 4913528 (1990-04-01), Hasegawa
patent: 4922477 (1990-05-01), Miura
patent: 4937440 (1990-06-01), Hofer et al.
patent: 5002365 (1991-03-01), DeJager et al.
Bouwhuis, et al., "Read-out of Optical Disk" in Principles of Optical Disk Systems, Adam Hilger Ltd., Bristol and Boston, pp. 70-80 (1985).
Bouwhuis et al., "Recording and Reading of Information on Optical Disks", in Applied Optics and Optical Engineering, R. R. Shannon and J. C. Wyant, eds., Academic Press, Inc., New York, vol. IX, pp. 101-110 (1983).
Cohen et al., "Automatic Focus Control: The Astigmatic Lens Approach", in Applied Optics, vol. 23, pp. 565-570, Feb. 15, 1984.
Yamamoto et al., "Optical Pregroove Dimensions: Design Considerations", in Applied Optics, vol. 25, No. 22, pp. 4031-4034, Nov. 15, 1986.
Arai et al., "New Focusing Method for Draw-Type Optical Head" in Optical Data Storage, Optical Society of America, Washington, D.C., pp. 1-4, Oct. 15-17, 1985.
Equichi et al., "An 86mm magneto-optical disk drive with a compact and fast-seek-time optical head", from the Optical Data Storage Conference, Vancouver, Mar., 1990.
Prototype Specification Sheet for a magneto-optical disk drive, by Hitachi Product Brochure for the Model SMO-501 Optical Disk Drive, by Sony.
Yoshizumi et al., "Fast Access Actuator for Optical Disk Memory", SPIE, pp. 1-4, 1985.
Product Brochure for the Model NE-5001 Half Height Optical Disk Drive, Nov., 1989 by the Nissho Electronics Corporation.
Yamanaka et al., "Compact Magneto-Optical Disk Head Integrated with Chip Elements", OSA/SPIE/IEEE 1991 Technical Digest Series, vol. 5, pp. 138-141, Feb. 25-27, 1991.
Musha et al., "An Optical Head for Digital Audio Discs (DAD)", Research Dept., Research and Development Division, Olympus Optical Co., Ltd. 2951, Ishikawa-cho, Hachioji-shi, Tokyo, Japan 192.
Hall, II Hollis O'Neal
Prikryl Ivan
Shuman Curtis A.
Allen Stephone B.
Applied Magnetics Corporation
Nelms David C.
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