Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1998-10-14
2001-06-19
Edun, Muhammad (Department: 2651)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S053410, C369S053450, C369S047100
Reexamination Certificate
active
06249499
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an optical disc drive for playing back or recording and playing back an optical disc and a method of descriminating optical discs.
2. Description of the Prior Art
There are known optical disc drives for recording and playing back an optical disc such as a CD (compact disc), CD-ROM, CD-R (CD-Recordable) and CD-RW.
In general, due to their respective recording layer properties, the CD, CD-ROM and CD-R are classified as high-reflectance optical discs, and the CD-RW is classified as a low-reflectance optical disc.
In this connection, in recent years, optical disc drives which can playback or reproduce two or more types of the high reflectance optical discs selectively with a single optical disc drive are proposed. Examples of such optical disc drives include an optical disc drive which can playback or reproduce CD-ROM and CD-R.
However, an optical disc drive which can playback or record and playback not only the high-reflectance optical disc but also the low-reflectance optical disc with a single optical disc drive has not yet been known in the prior art.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an optical disc drive which can easily and reliably playback or record and playback two or more types of optical discs having different reflectances (i.e., high-reflectance optical disc and low-reflectance optical disc).
It is another object of the present invention to provide a method of discriminating a loaded optical disc used in an optical disc drive which can play back or record and play back different types of optical discs having different reflectances.
In order to achieve the object, the present invention is directed to an optical disc drive which can play back or record and play back different types of optical discs having different reflectances. The optical disc drive comprises:
a driving mechanism for rotating an optical disc;
detecting means for receiving light reflected from the optical disc and detecting a quantity of the received light based on a signal obtained from the received light;
discriminating means for discriminating the type of the optical disc based on the obtained signal which varies by the difference between the reflectances of the optical discs.
In the present invention, the optical discs having different reflectances include a high-reflectance optical disc and a low-reflectance optical disc, and the discriminating means discriminates as to whether or not the optical disc is the high-reflectance optical disc and the low-reflectance optical disc.
It is preferred that the receiving and detecting means includes means for amplifying the obtained signal at a first amplification level and at a second amplification level which is different from the first amplification level.
In this case, the discriminating means includes first discriminating means for discriminating the type of the optical disc based on the signal amplified at the first amplification level, and second discriminating means for discriminating the type of the optical disc based on the signal amplified at the second amplification when the type of the optical disc has not been discriminated by the first discriminating means.
Further, in the present invention, the second amplification level is higher than the first amplification level, in which the first discriminating means is used for discriminating the high-reflectance optical disc and the second discriminating means is used for discriminating the low-reflectance optical disc.
In the present invention, it is also preferred that the optical disc drive further includes means for discriminating the type of the optical disc based on information carried by the optical disc to identify the type of the optical disc.
Preferably, the information is time information previously recorded on the optical disc.
Further, it is preferred that the optical disc drive further includes means for setting recording and playing back condition suitable for the finally discriminated type of the optical disc.
As described above, the optical disc drive of the present invention can playback or record and playback optical discs selected from a plurality of optical disc types having different reflectances (i.e., high reflectance optical discs and low reflectance optical discs).
In particular, because the optical disc drive includes the discriminating means for discriminating the type of the optical disc based on information carried by the optical disc to identify the type of the optical disc, it becomes possible to more reliably playback or record and playback optical discs selected from a plurality of optical disc types having the different reflectances including the high-reflectance disc and the low-reflectances optical disc.
Another aspect of the present invention is directed to an optical disc drive which can play back or record and play back different types of optical discs having different reflectances. The optical disc comprises a driving mechanism for rotating an optical disc; means for receiving light reflected from the optical disc and detecting a quantity of the received light based on a signal obtained from the received light, said means includes means for amplifying the obtained signal at a first amplification level and at a second amplification level which is higher than the first amplification level; first discriminating means for discriminating the type of the optical disc based on the signal amplified at the first amplification level; second discriminating means for discriminating the type of the optical disc based on the signal amplified at the second amplification; and third discriminating means for discriminating the type of the optical disc based on information carried by the optical disc to identify the type of the optical disc.
In the above configuration, the second discriminating means is used in the case where the first discriminating means can not discriminate the type of the optical disc, and the third discriminating means is used in the case where the second discriminating means can not discriminate the type of the optical disc.
Further, it is preferred that the first discriminating means is used for discriminating as to whether the optical disc is the high-reflectance optical disc or not, the second discriminating means is used for discriminating as to whether the optical disc is the low-reflectance optical disc or not, and the third discriminating means is used for compensating the discriminated result of the second discriminating means.
Preferably, the information is time information previously recorded on the optical disc.
Preferably, the optical disc drive further comprises means for setting recording and playing back condition suitable for the finally discriminated type of the optical disc.
Other aspect of the present inventin is directed to a method of discriminating a loaded optical disc used in an optical disc drive which can play back or record and play back different types of optical discs having different reflectances. The method comprising the steps of: receiving reflected light from the loaded optical disc to produce a signal corresponding to the quantity of the received light, the signal being amplified at a first amplification level; discriminating the type of the loaded optical disc based on the signal amplified at the first amplification level; and discriminating the type of the loaded optical disc based on the signal amplified at a second amplification level which is higher than the first amplification level.
In the above method, it is preferred that the method further comprises the step of discriminating the type of the loaded optical disc based on the information carried by the optical disc.
Further, in this method, it is preferred that the first discriminating step discriminates as to whether the optical disc is the high-reflectance optical disc or not.
Furthermore, in this method, it is preferred that the second discriminating step discriminates as to whether the optical disc is the low-reflectance optical di
Edun Muhammad
Mitsumi Electric Company
Patents+TMS
LandOfFree
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