Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
2001-03-26
2004-05-04
Korzuch, William (Department: 2653)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S053260, C369S059110
Reexamination Certificate
active
06731586
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Application Nos. 00-15031 and 01-6979 filed Mar. 24, 2000 and Feb. 13, 2001, respectively, in the Korean Patent Office, the disclosures of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for optical recording/reproducing and a method therefor, and more particularly, to an auto laser diode power controlling apparatus for controlling a power level of a laser diode to be in an optimal state and a method therefor.
2. Description of the Related Art
Modern society is often called an information-oriented society or a multimedia society. In this society, high capacity recording media are required. Magnetic optical disc drives (MODDs) and digital versatile disc random access memories (DVD-RAMs), which are optical recording apparatuses, are used as the recording media. Since the optical recording apparatuses use laser diodes, the performance of equipment is determined by controlling the laser diodes to be in an optimal state. Since the types of recording pulses required by the respective optical recording devices are different, effective compensation for the different types of recording pulses is required.
FIG. 1
is a block diagram showing the structure of a conventional apparatus for controlling auto laser diode power level.
The apparatus shown in
FIG. 1
includes an interface portion
110
, a decoder
120
, an address controller
130
, a pulse generator
140
, an auto laser diode power control (ALPC) block
150
, a laser diode (LD) driver
160
, a photodetector
170
, and a time delay
180
.
The interface portion
110
communicates with an external processor (not shown), for example, the microprocessor of a computer, and transmits information on recording/reproducing data, control data, and a use mode to the micro processor, and receives information on recording/reproducing data, control data, and a use mode from the micro processor. The decoder
120
includes an address decoder
121
, a register
122
, and a multiplexer
123
for selecting one among various registers included in the register
122
. The address controller
130
may also include various registers and sub blocks for realizing functions and controls the entire apparatus.
The laser diode driver
160
is a device in which high speed switching can be performed, and can include an additional common use integrated circuit (IC) or an application specific integrated circuit (ASIC). The pulse generator
140
generates a signal for generating and controlling the respective recording pulses for forming a domain on a recording medium corresponding to data to be recorded. The time delay
180
is for delaying a signal from the pulse generator
140
.
The ALPC block
150
detects a difference between a reference power level provided by the decoder
120
and the current power level provided from the photodetector
170
and controls the laser diode driver
160
according to the detection result.
The operation of the apparatus shown in
FIG. 1
will be described. Since the interface portion
110
is different according to the structure of a particular system, the following explanation assumes that the functions of the interface portion
110
have already been performed.
The decoder
120
selects and maintains a target power level (read power, erase power, and peak power as a reference power level). The selected reference power level is input to the ALPC block
150
, to which at least three reference power levels such as the read power, the erase power, and the peak power are input.
The respective reference power levels are digital to analog converted by a first D/A converter
151
and provided to a comparator
152
. The photodetector signal output from the photodetector
170
is provided to the comparator
152
through a buffer (not shown). At this time, a signal to control the operation of the comparator
152
is generated by the pulse generator
140
and provided to the comparator
152
through the time delay
180
.
An up/down counter
153
performs up or down counting according to the comparison result of the comparator
152
. An output of the up/down counter
153
is selected by a second demultiplexer
154
, converted into an analog to digital signal through a second D/A converter
155
, and provided to the LD driver
160
. A control signal for controlling the respective power levels provided by the ALPC block
150
and the respective power levels provided by the pulse generator
140
is input to the LD driver
160
.
The apparatus shown in
FIG. 1
uses the up/down counter
153
in performing controlling by comparing a reference power level with a fed back current power level. However, as the reproducing and recording speed of media becomes faster, controlling speed and a control range are restricted by the operation speed of the up/down counter
153
.
Since the width of a recording pulse becomes shorter and more complicated as the recording speed of media increases, a compensation for these characteristics of the recording pulse is necessary.
SUMMARY OF THE INVENTION
To solve the above problems, it is an object of the present invention to provide an auto laser diode power controlling apparatus for controlling a laser diode to be in an optimal state.
It is another object of the present invention to provide an auto laser diode power controlling method of controlling a laser diode to be in an optimal state.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the invention.
Accordingly, to achieve the above and other objects of the present invention, there is provided an auto laser diode power controlling apparatus for controlling the output of a laser diode by comparing the current power level of an optical signal output by the LD with a reference power level and controlling the output of the LD according to the comparison result. A photo detector (PD) monitors the current power level of the optical signal output by the LD. A sampler and holder samples and holds the current power level output from the PD. A sample and hold control signal generator generates a sample and hold control signal which controls the sampling operation of the sampler and holder on the basis of a non return to zero inverted (NRZI) signal, and an operator compares the current power level sampled by the sampler and holder with the reference power level and controls the output of the LD according to the difference value.
To achieve another object, there is provided an auto laser diode power controlling method which controls the output of a laser diode by comparing the current power level with a reference power level and controlling the output of the LD according to the comparison result. The method comprises monitoring the current power level of an optical signal output from the LD with a photodetector (PD), sampling and holding the current power level output from the PD on the basis of a NRZI signal, comparing the sampled and held current power level with the reference power level and controlling the output of the LD according to a difference level between the sampled and held current power level and the reference level.
REFERENCES:
patent: 4796250 (1989-01-01), Kobayashi et al.
patent: 5490127 (1996-02-01), Ohta et al.
patent: 5546372 (1996-08-01), Ohsawa et al.
patent: 5586098 (1996-12-01), Nishida et al.
patent: 5732061 (1998-03-01), Kirino et al.
patent: 5991251 (1999-11-01), Sakurai et al.
patent: 6222815 (2001-04-01), Nagano
patent: 6317405 (2001-11-01), Arai
patent: 6341117 (2002-01-01), Seo
patent: 0933759 (1999-08-01), None
Go Sung-ro
Jin Kyoung-bog
Seo Jin gyo
Chu Kim-Kwok
Korzuch William
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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