Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1998-02-04
2001-02-13
Edun, Muhammad (Department: 2753)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S044290, C369S047360
Reexamination Certificate
active
06188657
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for testing the quality of an optical disk medium; and more particularly, to such a method and apparatus having improved accuracy and reliability.
2. Description of Related Art
Optical disks are divided into three categories: (1) reproduction only such as CD and DVD-ROM, (2) write-once such as CD-R and DVD-R, and (3) rewritable such as CD-RW and DVD-RAM.
In spite of their different operating principles and usages, these optical disks have a similar structure such as shown in FIG.
1
. As shown, a base substrate
100
includes grooves
110
formed therein which also forms lands
120
between the grooves
110
. The side walls of the lands
120
are referred to as wobble because the side walls have alternating convex and concave curvature with respect to the center of the optical disk. When tracking a land or groove the adjacent wobble located closer to the center of the optical disk is referred to as the inner wobble, and the adjacent wobble located further from the center of the optical disk is referred to as the outer wobble.
Besides grooves, some of the above-referenced disks in their non-recorded state have pregrooves. Pregrooves are grooves including pits formed during the manufacture of the optical disk which define the format of the optical disk.
In their non-recorded state, optical disks are referred to as non-recorded optical disks. More specifically, a non-recorded optical disk is a disk that does not include user data such as program data.
With these optical disks conventional quality test methods involved recording signals in the lead-in area or main storage area of the disk, reproducing those test signals, and comparing the test signals to reference signals to determine quality.
Unfortunately, however, these methods cannot be applied to every optical disk manufactured. For instance, once test data is written into a write-once optical disk, that disk loses its value as a commercial good. Accordingly, samples from a plurality of manufactured optical disks are taken and tested according to the above-described methodology.
Besides rendering the sampled disks unusable, these quality testing techniques also prove to be inaccurate and unreliable. Just because the sampled disks may be of sufficient quality does not necessarily mean that the other disks, not sampled, are of sufficiently high quality. Therefore, these tests tend to be inaccurate and unreliable.
These optical disk media also undergo additional mechanical quality tests. For instance, the entire surface of the optical disk is displayed by monitoring the scanning of the optical disk surface with a laser beam using a CCD camera. The surface is then visually checked. Other tests include checking the location of the lead-in and lead-out for the main storage area.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a method and apparatus for testing the quality of an optical disk which overcomes the drawbacks and disadvantages discussed above.
Another object of the present invention is to provide a method and apparatus for testing the quality of an optical disk which has improved reliability and accuracy.
A further object of the present invention is to provide a method and apparatus for testing the quality of an optical disk which allows an optical disk to be both quality tested and usable thereafter.
A still further object of the present invention is to provide a method and apparatus for testing the quality of an optical disk which determine quality based on a laser beam reflected from a non-recorded optical disk.
An additional object of the present invention is to provide a method and apparatus for testing the quality of an optical disk which determine quality based on an auxiliary signal corresponding to a preformatted structure of an optical disk.
These and other objectives are achieved by providing a method of testing optical disk quality, comprising: reproducing an auxiliary signal from an optical disk, said auxiliary signal corresponding to a preformatted structure of said optical disk; and determining quality of said optical disk based on said auxiliary signal.
These and other objectives are further achieved by providing an apparatus for testing optical disk quality, comprising: reproducing means for reproducing an auxiliary signal from an optical disk, said auxiliary signal corresponding to a preformatted structure of said optical disk; and determining means for determining quality of said optical disk based on said auxiliary signal.
These and other objectives are also achieved by providing a method of testing optical disk quality, comprising: irradiating a non-recorded optical disk with a laser beam; detecting said laser beam reflected from said non-recorded optical disk; and determining disk quality based on said reflected laser beam.
These and other objectives are additionally achieved by providing an apparatus for testing optical disk quality, comprising: reproducing means for irradiating a non-recorded optical disk with a laser beam, and for detecting said laser beam reflected from said non-recorded optical disk; and determining means for determining disk quality based on said reflected laser beam.
Other objects, features, and characteristics of the present invention; methods, operation, and functions of the related elements of the structure; combination of parts; and economies of manufacture will become apparent from the following detailed description of the preferred embodiments and accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures.
REFERENCES:
patent: 5119359 (1992-06-01), Miyagi et al.
patent: 5256965 (1993-10-01), Nomura
patent: 5530687 (1996-06-01), Yamaguchi
Bae Dong-Seok
Kim Dae-Young
Kim Hyung-Kyu
Yeo Woon-Seong
Edun Muhammad
LG Electronics Inc.
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