Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Reexamination Certificate
2001-03-16
2004-04-20
Edun, Muhammad (Department: 2655)
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
C369S044280, C369S044250, C369S053100, C369S093000
Reexamination Certificate
active
06724697
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a layer jump control apparatus of a multilayer disk and a method thereof, in particular to a layer jump control apparatus of a multilayer disk and a method thereof which is capable of jumping accurately and rapidly on a request position by setting operation voltage variably in order to jump on a layer of the multilayer disk having at least two different record layers.
2. Description of the Prior Art
In general, an optical disk operation apparatus embodies a video and an audio by reading data recorded on the optical disk with optical pickup and releasing compression by processing the read signal.
The optical pickup reads the needed data by throwing laser on a set position of the optical disk and picking up the optical light.
In the present times, a DVD (Digital Versatile Disk) has spread as the optical disk. The digital versatile disk is the multilayer disk having at least two layers, and it can store larger amount of data than the conventional optical disk.
Meanwhile, in order to read the data recorded on the multilayer disk by the optical pickup, it can be transferred to each layer. In order to make an optical pickup
20
jump on the other layer, when a focus servo operation is OFF, the optical pickup can jump on the other layer by ascending an inner focus lens of the optical pickup rapidly by influence of a minus offset maintained itself.
However, in the above-mentioned method, because the inner focus lens of the optical pickup ascends rapidly, it passes a target layer.
It is possible to solve above-mentioned problem by performing the servo operation while ascending the focus lens slowly after descending the focus lens sufficiently.
The construction and operation of the above-described optical disk will now be described as below.
FIG. 1
is a block diagram illustrating a construction of a general optical disk apparatus. It comprises a multilayer disk
10
having at least two record layers, an optical pickup
20
for reading data recorded on the multilayer disk
10
, a spindle motor
50
for rotating the multilayer disk
10
, a RF unit
30
for generating a servo error signal (namely, a tracking error, hereinafter, it is referred to TE) and a focusing error (hereinafter, it is referred to FE) from a signal detected from the optical pickup
20
and outputting a binary signal by performing wave-filtering of a regenerative RF (radio Frequency) signal, a drive unit
60
for operating the spindle motor
50
and optical pickup
20
, a digital signal processing unit
40
for restoring the binary signal outputted from the RF unit
30
into the original data and controlling the operation of the drive unit
60
by the TE and FE signal, and a microcomputer
70
for outputting a control order to the digital signal processing unit
50
.
The operation of the above-described general optical disk apparatus will now be described.
When the regenerative signal is inputted to the microcomputer
70
from outside, the microcomputer
70
operates the spindle motor
50
by controlling the drive unit
60
, and operates the multilayer disk
10
. In addition, the microcomputer
70
detects a reflected light by controlling the optical pickup
20
. The detected signal is inputted to the RF unit
30
. The RF unit generates the TE, FE, and regenerative FR signals by the inputted signal. When the focusing and tracking error signals are inputted to the microcomputer
70
, the microcomputer
70
transmits the control signal to the digital signal processing unit
40
by the inputted error signal. The digital signal processing unit
40
controls the optical pickup
20
through the drive unit
60
in accordance with the inputted control signal. The optical pickup determines a target record layer and a track by the inputted control signal.
The data recorded on the multilayer disk
10
is read by the above-described processes, is converted into regenerative data in the digital signal processing unit
40
, and is outputted.
The operation when a layer up/down order is applied to the multilayer disk drive operation apparatus will now be described in detail with reference to accompanying
FIGS. 2 and 3
.
FIG. 2
is a construction profile illustrating a focusing actuator for operating the inner focusing lens of the optical pickup in the general multilayer disk, the position of the focusing lens is adjusted by the voltage applied to the focusing actuator, it can jump on the other layer of the multilayer disk.
FIG. 3
is a flow chart illustrating a layer jump operation of the conventional optical disk operating apparatus. When a layer jump order is inputted from the outside to the microcomputer
70
S
81
, the microcomputer
70
turns off the tracking and sled servo operation of the optical pickup
20
S
82
, and delays about for 5 msec in order to stabilize the optical pickup
20
S
83
.
The servo is the apparatus for adjusting automatically the optical pickup on an adjustable position of the multilayer disk. It can be divided into the tracking servo, sled servo, and focusing servo.
The tracking servo adjusts the optical pickup
20
accurately on a pit of a target track of the multilayer disk by adjusting it to left/right direction on the basis of the tracking error signal generated and outputted from the RF unit
30
.
The sled servo adjusts the position of the request track by adjusting the optical pickup
20
to radial direction from the center of the multilayer disk.
The focusing servo adjusts the optical pickup
20
to vertical direction on the basis of the focusing error signal generated and outputted form the RF unit
30
.
Meanwhile, after 5 msec passes, the microcomputer
70
turns off the focusing servo operation S
84
, and delays for 5 msec in order to stabilize the optical pickup
20
.
By the above-described process, when the all servo operation is OFF, the microcomputer
70
transmits an instruction word $
02
for layer jump to the digital signal processing unit
40
.
The instruction word $
02
is for descending the focus lens of the optical pickup vertically.
The digital signal processing unit
40
applies the focusing servo control voltage to the drive unit
60
by the inputted instruction word $
02
. The drive unit
60
controls to make the inner focus lens of the optical pickup
20
descend vertically for about 100 msec by the applied control voltage.
When the focus lens descends, the microcomputer
70
outputs an ascendant instruction word $
03
of the focus lens of the optical pickup
20
to the digital signal processing unit
40
.
The instruction word $
03
is for ascending the focus lens of the optical pickup
20
.
The digital signal processing unit
40
applies the operation voltage for ascending the focus lens of the optical pickup
20
to the drive unit
60
by the inputted instruction word.
The drive unit
60
applies the applied operation voltage to the focus actuator (depicted in
FIG. 2
) of the inner focus lens of the optical pickup
20
, and ascends the focus lens vertically for about 20 msec S
87
.
As described above, when the focus lens moves, the microcomputer
70
transmits an instruction word $
08
for turning on the focusing servo to the digital signal processing unit
40
S
88
.
The digital signal processing unit
40
transmits continually a FOK (Focus Okay) signal and a sense signal to the microcomputer
70
. Because the transmitted signals are generated in order to jump on a superior record layer, the microcomputer
70
ignores the FOK signal and sense signal about the first layer among the transmitted signal, and observes continually the FOK signal and sense signal about the second layer.
The FOK (Focus Okay) signal is a signal which is outputted when the focusing operation of the focus lens is performed normally. The sense signal is a signal outputted from a sense circuit of the digital signal processing unit
40
, its output is differentiated in accordance with a command on a microcomputer serial register, it is referred as a FZC (Focus Zero Crossing) for the focus servo control in the present
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