Optical head and recording and/or reproducing apparatus

Details Optical head and recording and/or reproducing apparatus Optical head and recording and/or reproducing apparatus

2007-10-09

2007-10-09

Psitos, A M (Department: 2627)

Dynamic information storage or retrieval

With servo positioning of transducer assembly over track...

Optical servo system

C369S112210, C369S120000

Reexamination Certificate

active

10794336

ABSTRACT:
An optical head in which pre-formatted signals may be detected as variations in the amplitude or the phase in the pre-formatted signals are suppressed, and a recording and/or reproducing apparatus employing the optical head, are disclosed. The optical head includes a light source212, an objective lens220for condensing a light beam radiated from the light source212on a recording track of an optical recording medium102, and a photodetector unit223for receiving the light beam reflected back from said recording track. The photodetector unit223includes a first light receiving section230band a second light receiving section230c. With a track pitch Tp of the optical recording medium, the wavelength λ of the light beam radiated from the light source212, the numerical aperture NA of the objective lens and with λ/(Tp·NA)≧4/3, the first light receiving section receives the light of one of two light spot areas lying on both sides of a center area of a light spot of the reflected light beam passing through the center of the light spot for extending along the length of the recording track. The second light receiving section receives the light of the other of the two light spot areas.

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patent: 2000-235715 (2000-08-01), None
patent: WO 00/39792 (2000-07-01), None
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“Simple Mo Head with Integrated Data and Servo Detection”,IBM Technical Disclosure Bulletin, vol. 41, No. 1, Jan. 1998, pp. 519-521.
Producing Linear Focus Error Signals in Optical Storage,IBM Technical Disclosure Bulletin, vol. 34, No. 10B, Mar. 1, 1992, pp. 228-229.

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