Optics: measuring and testing – Of light reflection
Reexamination Certificate
2001-02-28
2003-04-29
Lee, John R. (Department: 2881)
Optics: measuring and testing
Of light reflection
C356S071000, C356S448000, C369S053130, C369S094000, C369S044270, C369S053130, C369S044250
Reexamination Certificate
active
06556302
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for and a method of determining an information record medium, and more particularly relates to the apparatus for and the method of determining the information record medium, which can determine a type of the information record medium on which an information is optically recorded and reproduced.
2. Description of the Related Art
Recently, an information reproducing apparatus has been generalized which is superior in so-called compatibility and can reproduce information recorded on a plurality of types of optical discs that are different from each other.
On the other hand, when information is reproduced from the optical disc, typically, in order to make a focal point of a light beam for the reproduction coincide with a position on an information record surface of the optical disc, it is necessary to carry out the reproduction while carrying out a so-called focus servo control, tracking servo control or the like.
In the conventional various optical discs, their gain characteristics, equalizer characteristics, etc. which should be set in the above-mentioned respective servo controls are typically different from each other because of the differences between their structures.
Thus, when one information reproducing apparatus reproduces the information recorded on the respective optical discs, it is necessary to start the reproduction after the respective characteristics (the equalizer characteristics, the gain characteristics, etc.) in the information reproducing apparatus are optimized in accordance with a type of each optical disc. To this end, prior to the execution of the reproduction, it is necessary to determine a kind of an optical disc currently being loaded in the information reproducing apparatus and then optimize the gain characteristics, etc., in accordance with the determined result.
For this reason, various “type determining methods” of determining a type of an optical disc using a light beam for recording or reproducing have been proposed.
However, a so-called CD-R (Compact Disc-Recordable), which can record information only one time and which has been recently generalized, has a problem that it can not be discriminated from other optical discs even if any of the conventional type determining methods is used.
In a case of a light beam used in a conventional information reproducing apparatus for CD (Compact Disc), a record format and reflection characteristics to the light beam for the CD-R are substantially equal to those of another CD, etc. Thus, it is impossible to discriminate between the CD-R and the CD, etc., even if any of the conventional type determining methods using the light beam is used.
On the other hand, in recent years, it is necessary to reproduce the CD-R at hyper-multiplicative speed (e.g. 8×(eightfold), 10×(tenfold), 20×(twentyfold) . . . ). This case requires that the CD-R should be rotated at high speed. If information is accurately reproduced from the CD-R being rotated at high speed, the gain characteristics or the equalizer characteristics, which are acceptable at the time the CD-R is rotated at low speed even if they are adjusted roughly the same as those of the CD, needs to be optimized only for the CD-R. For this reason, discriminating the CD-R from other optical discs prior to the reproduction of the information has become increasingly significant.
SUMMARY OF THE INVENTION
The present invention is proposed in view of the above mentioned requests. It is therefore an object of the present invention to provide an apparatus for and a method of determining an information record medium, which can optically accurately determine a type of the information record medium among a plurality of types of information record media including CD-R.
The above object of the present invention can be achieved by an apparatus for determining an information record medium in accordance with the present invention. The apparatus has an emitting device for respectively emitting a plurality of light beams whose wave lengths are different from each other; a light receiving device for receiving respective reflection lights from an information record medium of the emitted respective light beams, and outputting light reception signals respectively corresponding to the received reflection lights; and a determining device for determining a type of the information record medium in accordance with a ratio between the outputted respective light reception signals.
According to the apparatus, the emitting device respectively emits a plurality of light beams whose wave lengths are different from each other. Then, a light receiving device receives respective reflection lights from an information record medium of the emitted respective light beams, and outputs light reception signals respectively corresponding to the received reflection lights. After that the determining device determines a type of the information record medium in accordance with a ratio between the outputted respective light reception signals.
Thus, a type of an information record medium is determined in accordance with a ratio between respective light reception signals respectively obtained by radiating a plurality of kinds of light beams to an information record medium. Therefore, the type can be determined optically accurately. As a result, after the type is accurately determined, recording or reproducing of the information on the information record medium can be reliably performed.
In one aspect of the apparatus for determining an information record medium of the present invention, the emitting device respectively emits a first light beam and a second light beam in which their wave lengths are different from each other. Then, the light receiving device receives a reflection light of the first light beam from the information record medium, and outputs a first light reception signal, and also receives a reflection light of the second light beam from the information record medium, and outputs a second light reception signal. After that, the determining device determines a type of the information record medium in accordance with a ratio between the first light reception signal and the second light reception signal.
Thus, the type of an information record medium is determined n accordance with a ratio between respective light reception signals respectively obtained by radiating two kinds of light beams to an information record medium. Therefore, the type can be determined optically accurately. As a result, after the type is accurately determined, recording or reproducing of the information on the information record medium can be reliably performed.
In another aspect of the apparatus for determining an information record medium of the present invention, a wave length of the first light beam is a wave length within a range between 770 nano-meters and 795 nano-meters, and a wave length of the second light beam is a wave length within a range between 630 nano-meters and 655 nano-meters.
Thus, a light beam used for recording or reproducing an information on or from an information record medium can be jointly used to then determine its type. Therefore, the configuration as an apparatus for determining an information record medium can be simplified.
In another aspect of the apparatus for determining an information record medium of the present invention, the determining device determines whether the information record medium is CD-R or another information record medium except the CD-R.
Thus, a determination for CD-R which was impossible until now can be optically done.
In another aspect of the apparatus for determining an information record medium of the present invention, the determining device compares the ratio with a predetermined threshold corresponding to a reflection factor of the light beam in the information record medium whose type should be determined, and so that it determines the type of the information record medium.
Thus, the type of an information record medium is determined in accordance with
Hashmi Zia R.
Lee John R.
Morgan & Lewis & Bockius, LLP
Pioneer Corporation
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