Lite-on It Corporation

Philips & Lite-on Digital Solutions Corporation

Tun-Chieh Lee

Jen-Yu Hsu

Hsiang-Yi Fu

Fu-Hsiang Chen

Yao-Chou Tsai

Yen-Chun Lin

Yi-Chung Lee

Ren-Chien Fu

Tsung-Yu Lu

Hung-Lung Tseng

A position control method of an optical pickup head of an optical disc drive is provided. The optical disc drive has an optical pickup head for reading data from an optical disc and a step index for controlling the movement of the optical pickup head. The position control method includes: calculating a first position information of the optical pickup head according to the step index; reading an address information from the optical disc, calculating a second position information of the optical pickup head according to the address information; determining whether a difference between the first position information and the second position information is greater than a predetermined value; updating the step index when the difference is not greater than the predetermined value; moving the optical pickup head to an initial position when the difference is greater than the predetermined value, and setting the step index as zero.

Position control method of optical pickup head of optical disc drive and system thereof

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.

Layer-jumping and focusing control method

A method and an apparatus of adjusting the tilt-angle of the lens in the optical pick-up head. The apparatus includes a position detecting unit for detecting a position deviation of the lens against the sled, a parameter generating unit for generating a tilt control parameter according to the position deviation, and a tilt control unit for controlling the lens according to the tilt control parameter so that the lens maintains horizontal with reference to the sled.

Method and apparatus for controlling tilt-angle of lens in optical pick-up head

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.

Speed error compensation method for optical storage device

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. Then, a second moving distance is measured by using a second force driven on the movable optical pick up head for the pre-determined distance, wherein the second force and the first force have opposite direction but the same amplitude. Next, when the difference between the first and second moving time falls within a pre-determined value, the optical disk drive is horizontal orientation.

Method of detecting orientation of optical disk drive

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.

Method and apparatus for DVD recognition using inner and outer tracking error signals

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.

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Taipei, Taiwan

Tun-Chieh Lee