发明名称 |
System and method for controlling focus in an optical disc drive |
摘要 |
A system for controlling focus in an optical disc drive for optical media with a premastered area that cannot be overwritten and a user-writeable area that can be overwritten includes instructions for turning focus on and off; and for acquiring focus on the optical media in response to a command to acquire focus. The actuator arm is moved according to a sinusoidal ramp function to prevent exciting resonances in the actuator arm. The amount of push-away force used while moving the actuator arm can be adjusted to avoid overshoot. The integrity of a focus error signal is determined and an attempt to re-acquire focus is made if the focus error signal indicates a bad focus status. The system turns focus off when at least one of the following conditions are met: (1) current state is a ramp focus acquire state and the maximum ramp position was reached; (2) current state is a focus push retry state and best push away value is greater than or equal to a predetermined fraction of a nominal push away value; or (3) a focus problem develops while in a focus active state.
|
申请公布号 |
US7054242(B2) |
申请公布日期 |
2006.05.30 |
申请号 |
US20010951940 |
申请日期 |
2001.09.10 |
申请人 |
DPHI ACQUISITIONS, INC. |
发明人 |
TURNER CHRISTOPHER J.;KADLEC RON J.;WATT CHARLES R. |
分类号 |
G11B7/00;G11B7/085;G11B7/09;G11B7/095;G11B7/12;G11B7/13;G11B7/135;G11B19/28 |
主分类号 |
G11B7/00 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|