Dynamic information storage or retrieval – Binary pulse train information signal – Binary signal gain processing
Reexamination Certificate
1998-08-14
2001-01-30
Edun, Muhammad (Department: 2753)
Dynamic information storage or retrieval
Binary pulse train information signal
Binary signal gain processing
C369S047360, C369S053130
Reexamination Certificate
active
06181659
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an optical information recording apparatus and an optical information recording method, which are applied to recording apparatus for, for example, compact discs (CD) and digital video discs (DVD).
According to the present invention, excellent pits are formed over the entire surface of a disc and a high quality disc in comparison with conventional discs is provided by controlling the timing of laser beam irradiation during recording correspondingly to the radial position where recording is now performed and the recording pattern.
2. Description of Related Art
Heretofore, for example, in a recording apparatus for compact discs namely an optical information recording medium of this sort, data for recording is subjected to data processing, followed by EFM (Eight-to-Fourteen Modulation), thus a bit string having a period of 3T to 11T is generated with respect to a predetermined basic period T, and an audio data is recorded.
Correspondingly, in a compact disc player, a laser beam is irradiated onto a compact disc and the return beam is received, a reproduction signal having the signal level which changes correspondingly to the light quantity of return beam is obtained, the reproduction signal is binarized with a predetermined slice level to generate a binarized signal. A PLL circuit is driven using the binarized signal to generate a reproduction clock, the binarized signal is latched successively by the reproduction clock, and a reproduction data having a period of 3T to 11T corresponding to the pit string formed on a compact disc is generated.
The compact disc player decodes the reproduction data generated as described herein above by performing data processing corresponding to the data processing performed when recording, and the audio data recorded in a compact disc is reproduced.
As for recording and reproduction of such conventional compact disc (CD), Japanese Published Unexamined Patent Application No. Sho 58-2628 discloses a disc recording apparatus in which the pit is formed on a disc so that a reproduction signal is obtained without deviation from the recording signal by changing output power of a laser beam and by reducing the pulse width of a pulse signal. Japanese Published Unexamined Patent Application No. Hei 3-83230 discloses an optical recording apparatus in which a write pulse having a pulse width shorter by pulse width decrement corresponding to the length increment of the pit due to a thermal time constant of the optical recording medium is generated from a base band signal, the recording light which is pulse width-modulated using the write pulse is irradiated onto the optical recording medium, and the pit with a normal length is formed on the optical recording medium having a large thermal time constant correspondingly to the base band signal. Japanese Published Unexamined Patent Application No. Sho 62-54830 discloses an optical disc recording reproduction apparatus for realizing the optimal recording condition of a used disc and environmental condition regardless of difference in recording sensitivity of respective discs or regardless of fluctuation of a laser beam due to temperature change to improve the reliability of the reproduction signal, and for realizing high density information recording in which apparatus recording is performed with successive changing of the pulse width of the laser beam and the pulse width is selected when the pulse width of the reproduction signal is in a predetermined desired range.
Recently, reproduction of a compact disc at high transmission rate has been generalized. In a high transmission rate reproduction apparatus, a compact disc is rotated, for example, at a speed 8 or more times the prescribed speed to reproduce data at high rate. By using a high transmission rate reproduction apparatus, data of the same quantity is obtained within a far shorter time in comparison with the conventional transmission rate.
In order to reproduce data at a high transmission rate, high speed disc rotation and wide band electronic circuits are required. Because a wide band electronic circuit is generally involved in high noise level problem, in order to reproduce signals stably in high noise level environment, jitter of a disc should be reduced.
The present invention has been accomplished in view of this point, it is the object of the present invention to provide an optical information recording apparatus and an optical information recording method which are capable of reducing jitter generated from a disc and capable of decoding signals stably at high transmission rate.
SUMMARY OF THE INVENTION
To solve the above-mentioned problem, an optical information recording apparatus of the present invention for forming pits on an optical recording medium by on-off controlling a laser beam based on a modulation signal generated by modulating an recording signal is provided with a radial position detection means for detecting the radial position where recording is now performed, a pattern detection means for determining the pattern of the modulation signal, and a timing correction means for adjusting the edge position based on both outputs from the pattern detection means and the radial position detection means.
An optical information recording method of the present invention is a method in which the signal level of a modulation signal is switched, a laser beam is modulated based on the modulation signal to form successively pits, and desired data is recorded in the form of pit, wherein the radial position where recording is now performed and variable pattern of a recording signal are detected, the edge position of the modulation signal is moved based on the radial position and pattern of the recording signal, and thereafter recording is performed.
The optical information recording apparatus and an optical information recording method function as described herein under.
In the present invention, the modulation signal having the signal level which is switched based on data is generated, the edge position of the modulation signal is corrected correspondingly to the variable pattern of the modulation signal and the radial position where recording is now performed, and thereafter the pit is formed on an optical recording medium by on-off controlling the laser beam for recording.
Hence in the optical information recording apparatus, jitter due to deviation of pit configuration from the ideal is eliminated by adjusting finely the edge position of the recording pulse based on the recording pattern, and a disc with reduced jitter is realized. Further, jitter due to inter-symbol interference of signals recorded on a disc is reduced. Because the edge position is adjusted based on the radial position, the edge position is finely corrected over the entire surface of a disc correctly. As the result, the total jitter is reduced, signals are reproduced stably regardless of somewhat high noise level due to high transmission rate.
REFERENCES:
patent: 5459710 (1995-10-01), Hoshino et al.
patent: 5553042 (1996-09-01), Usui
patent: 5559777 (1996-09-01), Maeda et al.
Edun Muhammad
Sonnenschein Nath & Rosenthal
Sony Corporation
LandOfFree
Optical information recording method for optical information... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical information recording method for optical information..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical information recording method for optical information... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2499713