Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Mechanism control by the control signal
Reexamination Certificate
1999-08-20
2002-06-11
Edun, Muhammad (Department: 2653)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Mechanism control by the control signal
C369S059110
Reexamination Certificate
active
06404712
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for recording information on an optical recording medium, and more particularly, but not by way of limitation, to a method and apparatus for recording information on an optical recording medium, which detects an optimal writing power for recording data on the optical recording medium and records information using the detected optimal writing power.
2. Description of the Related Art
FIG. 1
is a simplified block diagram of an apparatus for recording/reproducing data on/from an optical disk. The apparatus comprises an A/D converter
20
for digitizing analog signals, an MPEG encoder
30
for encoding the digitized data in the MPEG format, a digital recording signal processing unit
70
a
for converting the MPEG-formatted data into recording-formatted data by adding error correction codes, channel bit encoder
80
for converting the recording-formatted data into a bit stream, an optical driver
81
for yielding signals to drive an optical source, a pickup
11
for recording signals on optical disk
10
and reproducing recorded signals from optical disk
10
, a driver unit
90
for driving pickup
11
and a motor M, an R/F unit
100
for equalizing and shaping the signals reproduced by pickup
11
to produce binary signals, a servo unit
110
for controlling driver unit
90
using tracking and focusing error signals provided by pickup
11
and the rotation velocity of optical disk
10
, digital reproduced signal processing unit
70
b
for retrieving compressed data from the binary signals using a clock synchronized with the binary signals, an MPEG decoder
120
for retrieving original video/audio data by decoding the compressed data, and a microcomputer
60
.
Receiving a request for data recording, microcomputer
60
executes an OPC (Optimal Power Calibration) routine, which will be explained below in detail.
Before recording data, microcomputer
60
controls pickup
11
through servo unit
110
and driver unit
90
to read the indicative target writing power (Pind) recorded on recording medium
10
. In the case where disk
10
is a rewritable recording medium such as CD-RW, the target writing power is recorded as 3-bit data (W
1
,W
2
,W
3
) in the M
1
information byte in the field of ATIP (Absolute Time In Pre-Groove) located in the lead-in area of optical disk
10
, as shown in FIG.
2
.
After reading the target writing power, microcomputer
60
transfers its own test data to channel bit encoder
80
via digital recording signal processing unit
70
a
. For recording the digital bit stream outputted from digital recording signal processing unit
70
a
, channel bit encoder
80
convert the bit stream into pulse-width-modulated signal and transfers the modulated signal to optical driver
81
.
Microcomputer
60
applies a power adjustment signal (as shown in
FIG. 3
) to optical driver
81
for varying the writing power within a given range with respect to the indicative target writing power. In response to the power adjustment signal, optical driver
81
outputs recording signals of the writing power corresponding to the given power adjustment signal so that pickup
11
records the test data in the test area of optical disk
10
. In the case where optical disk
10
is a rewritable CD (CD-RW), the test data is recorded in the test area A located in the PCA (Power Calibration Area) shown in
FIG. 4
, whereas if optical disk
10
is a DVD, the test data is recorded in the drive test zone shown in FIG.
5
.
Along with recording the test data on a rewritable disk, microcomputer
60
controls pickup
11
to record the number of tests in the count area B located in the PCA. For example, if recording of the test data is executed three times, null data block is also recorded in the count area B three times (as shown in FIG.
4
).
On the condition that the test data is recorded in a specific area of optical disk
10
with varying writing powers, microcomputer
60
reproduces the most recently recorded test data by controlling pickup
11
. While reproducing the test data, microcomputer
60
continuously examines the quality of the reproduced signal such as the jitter characteristic for detecting the optimal writing power (Pop in FIG.
3
), which shows the reproduced signal having the best quality. The value of the optimal writing power is stored.
If external video or audio data is received for recording after the optimal writing power is obtained, the received data is digitized by A/D converter
20
and encoded in the MPEG format by MPEG encoder
30
. Digital recording signal processing unit
70
a
generates a data bit stream after adding parity for enhancing data recording/reproducing reliability. For recording the digital bit stream, channel bit encoder
80
converts the digital bit stream into pulse-width-modulated signals and applies the modulated signals to optical driver
81
.
Microcomputer
60
controls optical driver
80
so that it produces a laser beam of the optimal writing power obtained by the previous procedure. The pulse-width-modulated data is recorded in the program area of optical disk
10
by pickup
11
.
The audio or audio data is recorded in the area a (as shown in
FIG. 6
) with the obtained optimal writing power. If another request for recording data is received, microcomputer
60
repeats the aforementioned steps for recording test data and obtaining an optimal writing power and records the data in the area b (shown in FIG.
6
), using the newly obtained optimal writing power.
In the conventional method for recording/reproducing data on an optical disk explained above, the procedure for recording test data and detecting the optimal writing power is repeated whenever a data recording is requested, which takes a relatively long time and delays the data recording operation. Moreover, since the optimal writing power is calculated for each data recording request, the data in each area of the recording medium has been recorded with different writing powers, as shown in FIG.
6
. When reproducing the recorded data, however, the gains of R/F unit
100
and servo unit
110
remain fixed. Consequently, though the data is optimally recorded, the recorded data is not reproduced with an optimal writing power, thereby creating data reproduction errors or delays in data playback operations.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method and apparatus for optimally recording information on an optical recording medium, which is capable of always recording information with an identical writing power and shortening the recording time by maintaining the information indicative of whether to execute the procedure for detecting the optimal writing power and using the preserved writing power.
The method for optimally recording information on an optical recording medium according to the present invention comprises the steps of reading the reference writing power from the optical recording medium, recording test data on the optical recording medium by changing the writing power within a range with respect to the reference writing power, detecting an optimal writing power from a property of the reproduced signal, and recording the information indicative of the fact that the procedure for detecting the optimal writing power has been conducted in a predetermined area of the optical recording medium.
The other method for optimally recording information on an optical recording medium according to the present invention comprises the steps of checking whether the procedure for detecting the optimal writing power has been executed before by reading the information recorded in a predetermined area of the optical recording medium, reading the value of the optical writing power recorded in the predetermined area based on the checked result, and recording user data on the optical recording medium using the read writing power.
According to the present invention, the reference power recorded in a specific area of the optical recording medium is read, and test
Bae Dong-Seok
Lee Seong-Ju
Edun Muhammad
LG Electronics Inc.
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