Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Patent
1995-03-08
1997-03-04
Epps, Georgia Y.
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
369124, 3692754, G11B 700
Patent
active
056087128
ABSTRACT:
Method and apparatus for improving the characteristics of the surface effects on a replicated optical disc the master for which is recorded on an optical recording apparatus which includes a writing light beam source and an optical modulator for modulating the intensity of the writing beam of light above and below a threshold level of a relatively moving recording medium in response to a modulator drive signal for recording information on the medium, the light beam being capable of forming a track of surface effects or indicia in the relatively moving master recording medium when the writing beam is above threshold and incapable of forming surface effects in the relatively moving recording medium when the writing beam is below threshold. The method includes receiving a substantially rectangular waveform intended to control the optical modulator. In one aspect of the invention, a radius dependent duty cycle ramp function is introduced into the optical modulator drive signal for altering the depth or height of recorded pits or bumps on the recording medium to compensate for the depth or height versus radius phenomenon experienced in the molding process. In another aspect, a pit or bump type dependent correction function is introduced into the optical modulator drive signal, whereby individual pit or bump physical characteristics are altered in accordance with pit or bump type to compensate for the depth or height versus pit or bump type phenomenon experienced in the molding process.
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Boyle William W.
Browne John F.
Li Shigang
Rilum John H.
Wilkinson Richard L.
Chu Kim-Kwok
Epps Georgia Y.
Optical Disc Corporation
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