Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Reexamination Certificate
2005-04-19
2005-04-19
Korzuch, William (Department: 2653)
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
C369S053230, C369S053280, C369S044110
Reexamination Certificate
active
06882605
ABSTRACT:
Focusing control for maintaining a distance between an objective lens and a recording medium constant is executed using light whose wavelength is longer than that of recording light and whose detection sensitivity is better than that of the recording light, and a deviation of a focal point of the recording light is detected using reflected light which is reflected by the recording medium to thereby correct a control target position for a focusing control circuit, whereby the distance between the objective lens and the recording medium is corrected to a desirable distance throughout recording. In this manner, excellent focusing control is performed on recording light which has a low detection sensitivity and belongs to the UV range, while correcting a focusing control position for the recording light throughout recording. As focusing control is executed such that the focal point of the recording light is located approximately at the center in the direction of a thickness of a photosensitive material film which is disposed on the recording medium, a fine pit is formed accurately.
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Japanese Office Action dated Jun. 15, 2003.
Chu Kim-Kwok
Korzuch William
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