Mediatek Corporation

Mediatek Incorporation

Chih-Yuan Chen

Jyh-Shin Pan

Gwo-Huei Wu

Chao-ming Huang

Chih-Chin Hsu

Shou-Ren Tsai

Yuh Cheng

Ying-Che Hung

Jin-Chuan Hsu

Ching-Ning Chiu

Hsiang-Ji Hsieh

A method and an apparatus for deciding a spherical aberration compensation (SAC) value for an optical storage medium are provided. The optical storage medium comprises at least one recording layer and a cover layer. The SAC value is suitable for a selected one of the at least one recording layer. First, a focus search on the optical storage medium is performed to derive a focus error (FE) signal in response to a testing SAC value. Then, a center level and a center basis corresponding to the testing SAC value according to the FE signal is determined. The SAC value according to the center level, the center basis, and the testing SAC value is also determined. When the center level and the center basis are equal, the SAC value is determined to be the testing SAC value.

Method and apparatus for deciding spherical aberration compensation value

An optical storage system modulates a laser beam based on a high frequency modulation (HFM) signal and a pattern to be recorded on an optical storage medium. At least one of an amplitude and a frequency of the HFM signal is adjusted when using the light beam to record the pattern on the optical storage medium or read data from the medium.

High frequency modulation of a light beam in optical recording

A detector is scanned across an optical storage medium having groove tracks and land tracks, each track having a wobble structure, to detect light reflected from the optical storage medium. A wobble signal and a tracking error signal are generated based on an output of the detector, and the wobble signal is sampled according to the tracking error signal. A determination about whether the detector is at the groove track or the land track is made based on the tracking error signal and a comparison of sampled values of the wobble signal.

Land/groove track and pickup head movement direction detection

An optical storage system includes an optical pickup unit movable across an optical medium. The optical pickup unit has a light detector, a laser diode, and a laser driver signal processor circuit. The laser driver signal processor circuit includes a detected signal processing block for outputting read signals corresponding to light received at the light detector, and a read signal processing block for processing the read signals and generating control signals or synthesis signals according to the read signals. A control unit is coupled to the optical pickup unit for controlling the optical pickup unit and decoding data recovered from the optical medium. The optical storage system further includes encryption and decryption modules or error detection modules for securing commands and information sent between the control unit and the laser driver signal processor circuit against reverse engineering.

Optical storage system having integrated laser driver signal processor

An optical recording method and apparatus with different recording rates are provided for effectively increasing the average recording rate. The optical recording method includes the steps of: controlling a recording rate with a constant linear velocity (CLV) control mode; recording data; judging whether the recording rate has to be increased according to a rotating speed of a spindle motor or a recording position; and performing a process for changing the rotating speed if the recording rate is increased, and continuing recording data at the same recording rate if the recording rate is not increased. The step for changing the rotating speed includes the steps of: pausing recording data; registering a paused zone of a disc; determining a new rotating speed of the spindle motor, and driving the spindle motor at the new rotating speed; and linking recording zones to continue recording data at a new recording rate from the paused zone, when the rotating speed of the spindle motor is stable. Consequently, the invention can optimize the overall average recording rate by effectively utilizing the maximum rotating speed of the spindle motor in conjunction with the maximum recording rate.

Optical recording method and apparatus with different recording rates

An optical storage system includes an optical pickup unit movable across an optical medium. The optical pickup unit has a light detector, a laser diode, and a laser driver signal processor circuit. The laser driver signal processor circuit includes a detected signal processing block for outputting read signals corresponding to light received at the light detector, and a read signal processing block for processing the read signals and generating control signals or synthesis signals according to the read signals. A control unit is coupled to the optical pickup unit for controlling the optical pickup unit and decoding data recovered from the optical medium.

A shock detector for an optical disc recorder and method for controlling the recording using a shock signal. The shock detector includes a first detecting unit for detecting the amplitude of a first kind of reference signal passing through a band-pass filter and outputting a first detecting signal, a second detecting unit for detecting the level of a second kind of reference signal and outputting a second detecting signal, a third detecting unit for detecting the revolution of a third kind of reference signal and outputting a third detecting signal, and a judging unit for receiving the first detecting signal, the second detecting signal and the third detecting signal, and enabling a shock signal when the first detecting signal, the second detecting signal and the third detecting signal are simultaneously enabled. Therefore, the shock detector does not need an additional shock sensor.

Shock detector for optical disc recorders and shock-proof recording method using shock signal

An apparatus of detecting defects on an optical recording medium includes a defect signal generating circuit for generating a corresponding defect signal according to a surface defect of the optical recording medium, a first synchronous signal generator for generating a first synchronous signal, a defect signal locating circuit, a delay signal generating circuit, and an OR gate. The defect signal includes at least one pulse, whose width corresponds to the physical width of a surface defect. The delay signal generating circuit generates a delay signal corresponding to each pulse when the spacing between two adjacent pulses is smaller than a preset value. An OR operation is performed to the delay signal and the defect signal to obtain a defect extension signal. The first synchronous signal and a second synchronous signal for separating data recording sectors of the optical recording medium are employed to detect widths and addresses of surface defects.

Apparatus and method of detecting defects on optical recording media

In a method and apparatus for controlling the power of a laser beam in an optical recording system that includes a laser light source, an optical detector detects a reflected write pulse that is a reflection of an incident recording light signal from the optical recording medium, and a signal generating device generates a mark formation effectiveness (MFE) signal according to the reflected write pulse. A laser power compensation circuit includes a filter for filtering the MFE signal so as to result in a first component, and a combiner for combining the first component and the MFE signal so as to result in a second component. The laser power compensation circuit controls laser beam power of the laser light source according to the first and second components for optimum information recording.

Method and apparatus for controlling laser beam power in an optical recording system

An optical recording method and apparatus with different recording rates are provided for effectively increasing the average recording rate. The optical recording method includes the steps of: controlling a recording rate with a constant linear velocity (CLV) control mode; recording data; judging whether the recording rate has to be increased according to a rotating speed of a spindle motor or a recording position; and performing a process for changing the rotating speed if the recording rate is increased, and continuing recording data at the same recording rate if the recording rate is not increased. The step for changing the rotating speed includes the steps of: pausing recording data; registering a paused zone of a disc; determining a new rotating speed of the spindle motor, and driving the spindle motor at the new rotating speed; and linking recording zones to continue recording data at a new recording rate from the paused zone, when the rotating speed of the spindle motor is stable. Consequently, the invention can optimize the overall average recording rate by effectively utilizing the maximum rotating speed of the spindle motor in conjunction with the CD's maximum recording rate.

A defect detection method is used to generate a disc defect signal while recording or reproducing information recorded onto an optical disc. The method compares the difference between a reflected light intensity signal (SBAD) and a low-pass filtered SBAD with a predetermined level. A defect signal is generated during a period when the difference exceeds a predetermined value. The defect signal opens a switch to hold the low-passed signal of the SBAD and disconnects the low-pass filter from the SBAD at the moment a defect signal occurs. The held value of the low-passed signal effectively replaces the low-passed signal until the difference between the SBAD and held low-passed signal returns to within the predetermined limits, which re-closes the switch re-connecting the low-pass filter to the SBAD.

Growing community of inventors

Hsin-Chu, Taiwan

Chih-Yuan Chen