Driving apparatus of an optical recording medium
AssigneeSony Corporation
InventorsMichihiko Iida, Kunihiko Miyake
Life of this patent
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Abstract
A low-speed focus servo operation in which an objective lens is moved slowly is performed in a start process that is executed after mounting of an optical recording medium. On the other hand, a high-speed focus search operation in which the objective lens is moved fast is started when focusing is lost in a state that a focus servo operation is being performed. In the high-speed focus search operation, the focus servo characteristic is set to a modified version of a characteristic that is determined by a calibration operation that is performed in the start process.
Claims4
A driving apparatus which performs a recording and/or reproducing operation on an optical recording medium by applying laser light to the optical recording medium via an objective lens while controlling a position of the objective lens so as to focus the laser light on a recording surface of the optical recording medium, comprising:
- focusing means for performing a focus search operation for detecting a focus pull-in range by forcibly moving the objective lens, and for performing a focus servo operation for controlling the position of the objective lens so that it is pulled into a focusing position by closing a servo loop in a. state the objective lens is located in the focus pull-in range;
- and
- control means for causing the focusing means to perform a first focus search operation in which the objective lens is moved at a first speed in a start process that is executed after mounting of the optical recording medium, and a second focus search operation in which the objective lens is moved at a second speed that is higher than the first speed when focusing is lost in a state that the focus servo operation is being performed.
Dependencies are inferred from the claim text.