Abstract: In a layer jump and focusing control method, a first focusing error signal is generated according to the differential astigmatism method in a closed-loop focusing control manner when focusing on the first recording layer. A second focusing error signal is generated according to the astigmatic method in an open-loop focusing control manner when a first layer-jumping procedure is performed to shift a focusing position from the first recording layer to the second recording layer. Then, the completion of the first layer-jumping procedure is determined according to the second focusing error signal, for example when the second focusing error signal passes the zero crossing point and exceeds a threshold level. Afterwards, a third focusing error signal is generated according to the differential astigmatism method in a closed-loop focusing control manner when focusing on the second recording layer.

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.

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 detecting an unbalanced disc in a disc reading apparatus includes the following steps. Firstly, a disc is loaded into the disc reading apparatus. Then, a start-up procedure is performed at a first rotating speed. After the start-up procedure is completed, the disc reading apparatus enters a ready-to-read state. In the ready-to-read state, an unbalanced disc detection procedure is performed by detecting a vibration degree of the disc at a second rotating speed greater than the first rotating speed. Afterward, it is determined whether the disc is an unbalanced disc according to the vibration degree of the disc.

Abstract: In an optical reading apparatus, a light source, a high frequency modulator IC and a first resistor are integrated in an optical pickup unit, wherein the light source emits a light beam onto the optical storage medium in order to read information from the optical storage medium, the high frequency modulator generates a high frequency modulating signal for adjusting the intensity of the light beam, and the first resistor has a first end coupled to ground and a second end couple to a first pin of the high frequency modulator IC. A voltage control module disposed outside the optical pickup unit and coupled to the first resistor in parallel is used for adjusting an output current of the first pin in response to a voltage change thereof, thereby adjusting the amplitude of the high frequency modulating signal.

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: In a layer jump and focusing control method, a first focusing error signal is generated according to the differential astigmatism method in a closed-loop focusing control manner when focusing on the first recording layer. A second focusing error signal is generated according to the astigmatic method in an open-loop focusing control manner when a first layer-jumping procedure is performed to shift a focusing position from the first recording layer to the second recording layer. Then, the completion of the first layer-jumping procedure is determined according to the second focusing error signal, for example when the second focusing error signal passes the zero crossing point and exceeds a threshold level. Afterwards, a third focusing error signal is generated according to the differential astigmatism method in a closed-loop focusing control manner when focusing on the second recording layer.

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: An optical disk drive for compensating wobble signal and the method thereof. The compensating method is used in an optical pick-up head and a servo controller. The optical pick-up head includes a laser diode and a photo detectors. Firstly, the laser diode emits a beam focused on an optical disc to generate a reflective beam. Next, the photo detector receives the reflective beam to generate plural photo detecting signals. A servo controller receives the photo detecting signals to generate a processed signal. The objective lens is moved according to the processed signal. The photo detector receives the reflective beam to generate the photo detecting signals until the absolute value of the processed signal is not larger than a fixed value, then the photo detector receives the reflective beam to generate plural calibrated photo detecting signals. Lastly, a wobble signal is generated according to the calibrated photo detecting signals.

Abstract: An optical disk drive for compensating wobble signal and the method thereof. The compensating method is used in a servo controller and an optical pick-up head. The optical pick-up head includes a laser diode, a photo detector and an objective lens. The servo controller includes an auto gain controller. Firstly, a beam is emitted by the laser diode emits and is focused on an optical disc to generate a reflective beam. Next, the photo detector receives the reflective beam to generate plural photo-detecting signals received by the auto gain controller to generate a first control signal and a second control signal. Then, the servo controller generates a third control signal according to the first and the second control signals. The objective lens is moved according to the third control signal. Lastly, the photo detector receives the reflective beam to generate plural calibrated photo-detecting signals whereby a wobble signal is generated.

Abstract: A method for controlling a rotating speed of a disc for use in a disc reading apparatus includes the following steps. Firstly, the disc is loaded into the disc reading apparatus. Then, a start-up procedure is executed to discriminate whether to hoist a defect flag. Then, a ready-to-read state is entered to discriminate whether the defect flag is hoisted or not. Afterward, a reading procedure at a substantially constant rotating speed of the disc is executed if the defect flag is hoisted.

Abstract: A method for controlling a sled-home operation in an optical disc drive by driving a sled motor. The method includes two stages: a motor-starting stage and a sled-home-driving stage. In the motor-starting stage, the sled motor is driven at a first target speed. In the sled-home-driving stage, the target of the sled motor is gradually changed to a second target speed greater than the first target speed. The second target speed is less than or equal to the speed Rm that corresponds to a maximum allowable excitation frequency for the sled motor to overcome a dynamic friction torque and greater than the speed Rs that corresponds to a maximum allowable excitation frequency for the sled motor to overcome a static friction torque.

Abstract: The present invention discloses a method of improving seeking precision by adjusting the track to photo ratio in an optical disc drive. After a disk is tray in, the number of photos detected by the optical disk drive is pre-calculated when the optical pickup module is to seek a predetermined number of tracks. The actual number of seeking tracks performed by the optical pickup module is calculated after the optical disk drive has detected the pre-calculated number of photos. Thereafter an optimal track to photo ratio is obtained.

Abstract: A method of correcting a step number of a stepping motor in an optical drive is disclosed. After an optical disk is tray into the optical drive, a step number of the stepping motor for moving an optical pickup module by a predetermined number of tracks is firstly calculated. Then, a practical track number by which the optical pickup module is moved after the stepping motor has stepped by the step number is calculated. Thereafter, a corrective track/step ratio is obtained.

Abstract: The present invention discloses a method for controlling a pick-up head during a long seek. During a long seek, a bias voltage is applied to the pick-up head to overcome the inertia of the pick-up head and to prevent the pick-up head from oscillating. This makes it easier for the optical drive to execute the track-on action after a long seek.

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 the tracking action of an optical disk drive is disclosed. According to the method, the number of sine waves in the tracking error signals is calculated while the disk drive is conducting a long seek, to determine the number of tracks crossed by the optical pick up head. When the disk drive is about to perform tracking on action, the actual speed of the sledge is estimated by estimating the frequency of alternating high and low levels in an optical signal detected by the optical receiver. The tracking on action is carried out if the speed of the sledge is below a threshold value.

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 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.