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Method for discriminating track distance of compact disc

A technology of optical disc and track distance, which is applied to the recording/reproducing by optical method, optical recording head, beam guiding device, etc., and can solve the problems of long moving distance, inability of the optical head 140 to reach the target position quickly, and influence, etc.

Inactive Publication Date: 2011-09-21
SUNPLUS TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When calculating the moving distance of the optical head 140, if the wrong track gauge is used, the reading distance will be exceeded or insufficient, so that the optical head 140 cannot reach the target position E quickly.
For example, when using the track gauge of a standard CD disc with a track gauge of 1.6um to perform the tracking calculation of a CD-R disc with a track gauge of 1.4um, the moving distance will be too long due to the larger track gauge of the standard CD disc. Therefore, the detection track gauge has an important impact on long-distance tracking

Method used

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  • Method for discriminating track distance of compact disc
  • Method for discriminating track distance of compact disc
  • Method for discriminating track distance of compact disc

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0056] Please refer to figure 2 , figure 2 It is a schematic diagram of a disc track according to the first embodiment of the present invention. O is the center position of the optical disc, P is the initial position of the track, Q is a track of the optical disc, n is the number of tracks between the initial track and track Q, and d is the track pitch. The distance between positions O and P is r 0 , the distance between positions P and Q can be represented by n×d. The track of the optical disc is a spiral track formed by connecting multiple data sectors. Will figure 2 The left track unfolded into a straight line would look like figure 2 As shown in the figure on the right, the data track is like a data strip composed of rectangular data segments, and the length of each data segment is l.

[0057] Each data sector has a data sector address, and the data sector address is coded progressively from the inner track to the outer track of the optical disc. Therefore, the ...

no. 2 example

[0065] Ideally, the geometric center and the rotation center of the optical disc should be located at the same point. When the spindle motor rotates the optical disc, the track area of ​​the optical disc will rotate around the center of the optical disc. However, when there is a deviation in the manufacturing process of the optical disc, the orbital center and the geometric center of the optical disc will not be located at the same point, which is called eccentricity. When the axis that passes through the center of the disc and is parallel to the screw of the optical drive and the axis that passes through the center of the objective lens and is parallel to the screw of the optical drive are not coincident, we call it a de-center. When an eccentric optical disk or an axis-offset mechanism rotates, its orbit will have a radial upward movement component relative to the optical head. Therefore, the optical head at a fixed position will detect the cross-track signal, and the track ...

no. 3 example

[0080] Since the disc address to be read will be affected by two factors, the track gauge and the degree of eccentricity of the disc, such as Figure 10 shown. Figure 10 It is a test schematic diagram of disc T and disc S with two different track gauges and different eccentricity according to the third embodiment of the present invention. Disc S is a standard disc without eccentricity, and disc T is a disc with eccentricity K in the cross-track direction. Using the same reading distance X to read the disc T and the disc S, in the disc S, the distance between the locking rail position and the axis center of the spindle motor 12 can be expressed as R 0 +Ns×Ds; in the disc T, the distance between the locking rail position and the axis center of the spindle motor 12 can be expressed as R 0 +K+Nt×Dt, where R 0 Indicates the distance between the shaft center of the spindle motor 12 of the standard disc S and the inner side of the track area, Ns indicates the number of tracks rea...

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Abstract

The invention discloses a method for discriminating a track distance of a compact disc, which is applicable to a compact disc driver. The method comprises the following steps of: moving an optical pickup head to a preset position to keep the optical pickup head a preset distance away from the axis of a spindle motor; reading a data sector address on the compact disc; and discriminating the size of the track distance of the compact disc according to the size of a numerical value of the data sector address.

Description

technical field [0001] The invention relates to a method for identifying the track gauge of an optical disc, and in particular to a method for identifying the track gauge of an optical disc with only one tracking action. Background technique [0002] Optical discs can store a large amount of data and have become the most extensive storage medium at present, and optical disc drives for reading and writing optical discs have become necessary equipment for computers and home audio-visual devices (such as stereos, video recorders). [0003] The surface of the optical disc has data tracks to store data, and the data tracks are in the shape of a spiral, from the inside to the outside. There are multiple data segments on the data track, and each data segment has a uniquely identifiable data segment address, and the data segment addresses are set in a progressive encoding manner from inside to outside. Some traditional optical discs reduce the standard track pitch to increase the m...

Claims

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Application Information

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IPC IPC(8): G11B7/135G11B7/085
Inventor 张耀文吴秉儒
Owner SUNPLUS TECH CO LTD
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