Abstract: The present invention discloses a method of detecting orientation of an optical disk drive. Firstly, a first moving distance is measured by using a first force driven on a movable optical pick up head of the optical disk drive for a preset period. Next, a second moving distance is measured by using a second force driven on the movable optical pick up head for the preset period, wherein the second force and the first force have opposite direction but the same amplitude. Next, it is determined that the optical disk drive is horizontal orientation when the difference between the first and second moving distances falls within a pre-determined value. Additionally, a first moving time is measured by using a first force driven on a movable optical pick up head for a pre-determined distance.

Abstract: A method for arranging conducting lines of a flexible cable in an optical disk drive first confirms the pins having similar functions of all chips on a main board and a sub-board, and uses only one conducting line of the flexible cable to connect these pins. Therefore, the number of the conducting lines of the flexible cable can be reduced.

Abstract: A DVD recognition method and apparatus is disclosed. First, a disc recognition apparatus uses a laser with a specific wavelength to irradiate an inner area of the DVD, thereby obtaining an inner TE signal. Then, the disc recognition apparatus uses the laser to irradiate an outer area of the DVD, thereby obtaining an outer TE signal. Afterward, the type of the DVD is recognized according to the inner and outer TE signals.

Abstract: A method for correcting disc type determination is disclosed. The method detects a tracking error signal, and verifies accuracy of a disc type determination according thereto.

Abstract: A method of on-line adjusting a sled motor control signal (FMO) is disclosed. First, a predetermined FMO is assigned to move a sled for seeking, and a photo signal is monitored. The number of waveforms appearing in the photo signal and a distance from an optical pickup to a target track are calculated under this predetermined FMO. Then, the optical pickup is moved to the target track such that the optical pickup after seeking is located at a center position of a movable range. If the number of waveforms appearing in the photo signal is not equal to a predetermined number, the duration of the FMO is adjusted according to the difference therebetween.

Abstract: A method of controlling a sled motor control signal (FMO) is disclosed. First, a predetermined FMO is assigned to move a sled, and a photo signal is monitored. The FMO is off after a predetermined number of waveforms have appeared in the photo signal. Then, a position of an optical pickup is finely adjusted such that the optical pickup is at a center position of a movable range after the seeking operation.

Abstract: A method for arranging conducting lines of a flexible cable in an optical disk drive first confirms the pins having similar functions of all chips on a main board and a sub-board, and uses only one conducting line of the flexible cable to connect these pins. Therefore, the number of the conducting lines of the flexible cable can be reduced.

Abstract: A method for correcting a position of an optical pickup before track following is disclosed. The actual position of the optical pickup before seeking is detected. Then, a sled motor control signal is provided to compensate for the force of the sled seeking such that the optical pickup is at a center of a movable range after seeking.

Abstract: A method of disc protection during servo focusing is disclosed. First, the disc device performs a servo focusing on a disc at a first speed, and records the first focusing time accordingly. Afterward, the disc device calculates a second focusing time required for another servo focusing if the disc requires re-focusing, and re-focuses the disc if the second focusing time exceeds the first focusing time.

Abstract: A method for detecting an unbalanced optical disc in an optical disc drive. The unbalanced optical disc is detected by a pick-up head of the optical disc drive to obtain a tracking error signal. A first track-across number at which the pick-up head travels on the unbalanced optical disc is determined when the unbalanced optical disc rotates at a first rotational speed. A second track-across number at which the pick-up head travels on the unbalanced optical disc is determined when the unbalanced optical disc rotates at a second rotational speed. The first track-across number and second track-across number are computed to obtain a resulting value. The unbalanced level of the unbalanced optical disc is determined according to the resulting value.

Abstract: A method of braking control in rapid track seeking for an optical drive. The optical drive has a pickup head for reading information from an optical disc therein. According to the method, a tracking error signal is obtained in the rapid track seeking motion of the pickup head. A seeking velocity is obtained by calculation according to the tracking error signal. Since the seeking velocity varies, a braking force is determined according to the seeking velocity for braking the pickup head.

Abstract: A method for processing error control for a seeking servo of an optical disk drive includes calculating a “track on” time when control of a pickup head is switched from a seeking servo system to a tracking servo system to start a “track on” process, moving the pickup head to the center of a movable range when the “rack on” process is not completed in a predetermined time, and switching control of the pickup head to the tracking servo system to start another “track on” process.

Abstract: A method for preventing contact between a pickup head and an optical disc. First, a voltage is provided to the pickup head, thereby repositioning the pickup head closer to the optical disc from an initial position to a biased position. A track-seeking motion is executed to move the pickup head to a predetermined information track. The pickup head starts a vibration in the direction away from the disc when a focus error occurs during the track-seeking motion.

Abstract: A method of accelerating a track-following process for an optical drive. The optical drive has a motor and a pickup head for reading information from an optical disc therein. According to the method, an input signal with a first frequency and a first phase is received by detecting the rotation speed of the motor and a radius of the information track where the pickup head locates on the optical disc. When either frequency or phase of a data phase locked loop (DPLL) frequency signal of the optical drive is different from the first frequency and the first phase, the DPLL frequency signal is adjusted to the first frequency and the first phase. With the adjusted DPLL frequency signal, data from the optical disc is read correctly.

Abstract: A DVD recognition method and apparatus is disclosed. First, a disc recognition apparatus uses a laser with a specific wavelength to irradiate an inner area of the DVD, thereby obtaining an inner TE signal. Then, the disc recognition apparatus uses the laser to irradiate an outer area of the DVD, thereby obtaining an outer TE signal. Afterward, the type of the DVD is recognized according to the inner and outer TE signals.

Abstract: The present invention discloses a method for determining disc type. Perform a focus servo process by emitting a light beam with a specific wavelength and a focus error signal is generated. According to the overshooting value after the focus error signal forming an S curve, the disc type is determined.

Abstract: A method for correcting disc type determination is disclosed. The method detects a tracking error signal, and verifies accuracy of a disc type determination according thereto.

Abstract: A method for discriminating optical media type includes positioning a reading unit of the optical drive at a first position, moving the reading unit to a second position so that a light spot passes over a data layer of the optical media, continuing measuring the reflection of the laser beam to obtain a first time when the reflection is larger than a predetermined reflection, moving the reading unit back to the first position so that the light spot again passes over the data layer of the optical media, continuing measuring the reflection of the laser beam to obtain a second time when the reflection is larger than the predetermined reflection, and calculating the time difference between the second time and the first time and comparing with at least one predetermined time in order to discriminate the type of the optical media.

Abstract: The present invention discloses a method of detecting orientation of an optical disk drive. Firstly, a first moving distance is measured by using a first force driven on a movable optical pick up head of the optical disk drive for a preset period. Next, a second moving distance is measured by using a second force driven on the movable optical pick up head for the preset period, wherein the second force and the first force have opposite direction but the same amplitude. Next, it is determined that the optical disk drive is horizontal orientation when the difference between the first and second moving distances falls within a pre-determined value. Additionally, a first moving time is measured by using a first force driven on a movable optical pick up head for a pre-determined distance.

Abstract: The present invention discloses a system for speed error compensation. A predetermined speed signal subtracts a feedback speed signal to generate a speed error signal, and a microprocessor receives the speed error signal and outputs a calculated result. A feedback controller receives the calculated result and generates a first tracking control effort signal. A feedforward controller receives the speed error signal and generates a second tracking control effort signal according to a DC steady state error in the speed error signal. An optical head module moves at an actual speed determined by the total of the first tracking control effort signal and the second tracking control effort signal. A gain controller generates the feedback speed signal according to an actual speed signal detecting from the actual speed.