Koninklijke Philips Corporation N.v.

Creative Technology Corporation

Bin Chye Lim

Yam Fei Lian

Yew Teng Too

Rain Jilin Zhang

Chee Kang Thong

Shigeki Okazaki

A method and device are disclosed for improving reliability of reading an optical storage medium, such as an optical disc (). A disc spin speed value () of the optical disc () is provided and an unnormal value of said disc spin speed value (), which differs from a disc spin speed value within a range of nominal disc spin speed values, is detected, indicating normal spinning operation of said optical disc (). By using this method, the spinning loss of an optical disc, e.g. due to insufficient disc clamping force, is detected fastly and reliably, in a manner resulting in a reduced risk of damaging the disc and disc reader during such spinning loss. Further actions may be taken in both cases, including disabling the drive in order to prevent damage of the disc or to thwart such illegal usage.

Optical storage medium reading/writing method and device with improved reliability

In a CD drive , a tracking subsystem comprising tracking detector , a control processor and tracking actuator assembly , is coupled to photodiodes A-F, to have the lens assembly track a data track on a disc . A vibration detector subsystem comprising a vibration detector , the control processor , and the speed setting function , is also coupled to photodiodes A-F, and the vibration detector subsystem disables the tracking subsystem and detects vibration of the lens assembly at a resonant speed.

Method for detecting vibration in a disc drive and apparatus therefor

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Singapore, Singapore

Bin Chye Lim