Optical disc drive and method for detecting vertical deviation thereon
AssigneeHon Hai Precision Industry Co., Ltd.
InventorsCHI-FAN YU, I-CHUN TSENG, KUN-HUA LU
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Abstract
An optical disc drive includes a disc holder, a pickup head, a focus servo, an S-curve identifying unit, a first counter, a second counter, a judging unit, a disc identifying unit, and a system controller. The optical disc drive can detect whether a disc exhibits vertical deviation. Upon detection, the optical disc drive restricts the maximum speed of data reading and writing. The judging unit determines whether the disc exhibits vertical deviation based on a comparison result of the number of the one or more S curves with a first preset value.
Claims8
An optical disc drive comprising:
- a disc holder to hold a disc;
- a pickup head comprising a light source, a photo sensor, and an objective lens, the light source to emit light to pass through the objective lens and projecting on the disc, the photo sensor to detect reflected light reflected by the disc;
- a focus servo comprising a focus error signal (FES) generating unit, a focus driver, and a focus controller, the FES generating unit to generate a focus error signal according to a signal from the photo sensor, the focus driver to drive the objective lens to move with respect to the disc between an uppermost position and a lowermost position, the focus controller to control the focus driver to drive the objective lens;
- an S-curve identifying unit to determine whether one or more S curves appear in a waveform of the focus error signal when the lens moves from the lowermost position to uppermost position and;
- a counter to count the number of the one or more S curves;
- and
- a judging unit to determine whether the disc exhibits vertical deviation based on a comparison result of the number of the one or more S curves with a first preset value.
A method, implemented by an optical disc drive, for detecting a vertical deviation disc, the method comprising:
- controlling a focus driver to drive a lens to move with respect to a disc to a lowermost position when the disc is loaded;
- controlling a focus driver to drive the lens to move with respect to the disc from the lowermost position to an uppermost position, and controlling a light source to emit light;
- detecting reflected light reflected by the disc and generating a focus error signal based on the detected reflected light;
- counting the number of one or more S curves appearing in a waveform of the focus error signal when the lens moves from the lowermost position to the uppermost position;
- and
- determining whether the disc exhibits vertical deviation based on a comparison result of the number of the one or more S curves with a first preset value.
Dependencies are inferred from the claim text.