Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Mechanism control by the control signal
Reexamination Certificate
1999-09-16
2003-11-11
Edun, Muhammad (Department: 2655)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Mechanism control by the control signal
C369S047500, C369S053100, C369S059100, C369S116000
Reexamination Certificate
active
06646965
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recording/reproducing apparatus for a writable optical storage medium, and in particular to the optimization of writing parameters (for example, a writing light power, writing beam profile (or, writing strategy)) for writing of a writable optical storage medium, based on experimentally determined optimum test writing parameter for the writable optical storage medium according to the manufacturer thereof, by associating data indicative of the manufacturer of a writable optical storage medium and optimum test writing parameters corresponding to the medium manufacturer, and prior to writing an input signal into a writable optical storage medium, judging the medium manufacturer corresponding to a writable optical storage medium, setting the optimum test writing parameters corresponding thereto, and accordingly determining optimum writing parameters for the medium based by performing an optimization produce employing the thusly set optimum test writing parameters.
2. Description of the Background Art
FIG. 1
illustrates the construction of a conventional writable optical storage medium recording/reproducing apparatus which includes an A/D converter
20
converting an inputted analog signal into a digital signal, a MPEG encoder
30
encoding the digital signal from the A/D converter
20
into a MPEG format signal, a digital writing signal processing unit
70
a
converting the encoded signal into a writable format by adding an error correction code (ECC), channel bit encoder
80
for converting the signal converted into a writable format into a bit stream, a TC (Laser Diode) driving unit
81
receiving the signal from the channel bit encoder
80
and outputting an optical content driving signal, a pick-up unit
11
writing the input signal into the writable optical storage medium
10
or detecting the written signal in accordance with the optical content driving signal, a drive unit
90
driving the pick-up unit
11
and a spindle motor
91
, an R/F unit
100
receiving a signal detected by the pick-up unit
11
and a spindle motor
91
, an R/F unit
100
receiving a signal detected by the pick-up unit
11
and outputting a filtered and shaped signal, a servo unit
110
controlling the driving operation of the drive unit
90
based on a tracking error signal TE of the pick-up unit
11
, a focus error signal FE, and a rotation of the writable optical storage medium
10
and detecting a synchronous state of the output signal from the R/F unit
100
, a digital reproducing signal processing unit
70
b
recovering a compression write data from the filtered and shaped signal based on the detected synchronous signal, an MPEG decoder
120
decoding the compressed data, converting it into a video and audio signal and outputting the same, and a microcomputer
60
controlling the operations of the recording/reproducing apparatus.
The operation of the writable optical storage medium recording/reproducing apparatus will be explained with reference to the accompanying drawings.
First, when a signal KEYSIG is inputted into the microcomputer
60
requesting a writing operation of an inputted signal INPUT applied to the input terminal, the microcomputer
60
controls the pick-up unit
11
via the servo unit
110
and the drive unit
90
so that a writing light power value P
ind
written on the writable optical storage medium
10
is read-out before the input signal INPUT is written into the writable optical storage medium. In the case that the writable optical storage medium
10
is a rewritable medium such as a compact disc rewritable (CD-RW), as shown in
FIG. 2
, the writing light power value P
ind
is written in a data form of 3 bits W
1
, W
2
and W
3
at a M
1
information byte of a special information field in an Absolute Time In Pre-Groove (ATIP) signal format of a lead-in region of the writable optical storage medium
10
.
When the light power value P
ind
is read out from the data W
1
, W
2
and W
3
, the microcomputer
60
outputs test digital data (for example, 101010 . . . ) to the channel bit encoder
80
via the digital writing signal processing unit
70
a
, and the channel bit encoder
80
converts the digital bit stream outputted from the digital writing signal processing unit
70
a
into a signal format for writing into the writable optical storage medium
10
and then applies the converted signals to the LD driving unit
81
.
As shown in
FIG. 3
, the microcomputer
60
variably applies an adjusting signal to the LD driving unit
81
so that the magnitude of the light power value is changed in a certain range of P
ref+a
, P
ref−a
based on a reference writing light power (for example, P
ref
=8 mW) generated by the writing light power value P
ind
. The LD driving unit
81
outputs a test digital data based on the optical driving current corresponding to the adjusting signal, and the pick-up unit
11
writes the test digital data into the test writing region of the writable optical storage medium
10
. Here, in the case that the loaded writable optical storage medium
10
is a rewritable medium such as a CD-RW, as shown in
FIG. 4A
, the test writing region is formed in the PCA (Power Calibration Area). In particular, as shown in
FIG. 4B
, the microcomputer
60
causes the test digital data to be written into the test writing region of the rewritable optical storage medium and writes a certain information into the count region B of the PCA region so that the written number of the test digital data is recognized by controlling the pick-up unit
11
.
As the LD driving current is gradually varied, in a state that the test digital data is written in the test region A and the written number of data in the region A is written in the count region B of the PCA of the writable optical storage medium
10
, the microcomputer
60
controls the pick-up unit
11
, and the pick-up unit
11
reads out the test data written in the test region of the PCA region. The microcomputer
60
causes the R/F unit
100
to filter and shape the reproduced signal read-out by the pick-up unit
11
and continuously detects the jitter amount of the clock signal which is phase-synchronized to the reproducing signal by the servo unit
110
. The microcomputer
60
detects an optimum writing light power(in
FIG. 3
, P
op
) by which the test digital data is written at the time when the minimum jitter amount is detected from the clock signals.
When the optimum writing light power P
op
is determined, an analog signal such as an externally inputted video or audio signal is inputted into the A/D converter
20
for a writing operation at the writable optical storage medium
10
. In this state, the A/D converter
20
converts the inputted signal into a digital signal, and the MPEG encoder
30
encodes the digital signal based on the MPEG method. The digital writing signal processing unit
70
a
generates an error correction code (ECC) block by adding an encoding and error correction parity to the encoded signal in order to enhance reliability when writing the encoded signal into a writable optical storage medium
10
and output the generated code to the channel bit encoder
80
. The channel bit encoder
80
converts the digital bit stream data outputted from the digital writing signal processing unit
70
a
into a pulse width-modulated signal format for being written into a writable optical storage medium
10
.
Therefore, the microcomputer
60
controls the LD driving unit
81
using an optimum light driving current so that the pulse width-modulated signal is written into the writable optical storage medium
10
based on the optimum writing light power detected during the above-described operation. The LD driving unit
81
applies the pulse width-modulated signal to the pick-up unit
11
based on the optimum light driving current, and the pulse width-modulated signal is written in a user's data recording region of the writable optical storage medium
10
.
However, in the case that an optimum writing light power is
Birch & Stewart Kolasch & Birch, LLP
Edun Muhammad
LG Electronics Inc.
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