OPTICAL DISK DRAWING APPARATUS, OPTICAL DISK DRAWING
SYSTEM AND OPTICAL DISK DRAWING METHOD
[0001]
BACKGROUND OF THE INVENTION
The present invention is related to a technique fox-
drawing an image on a label surface side of an optical
disk.
[0002]
In the case that drawing operations are carried out
with respect to optical disks, methods for drawing the
optical disks by performing focus servo controls have
been known. However, the drawing operation may become
unstable in a certain case that a stable servo system
cannot be established due to fluctuations in reflectance
factors of respective optical disks, characteristic
fluctuations in actuators, fluctuations in laser light
amounts, temperature changes, and the like. Under such
a circumstance, the following technical ideas have been
developed (refer to, for example, JP-A-2002-203321 and
JP-A-2005-228382): That is, a focus servo gain control
is carried out just after an optical disk is inserted,
so that the servo system is adjusted to optimum condition
based upon reflection light of laser light irradiated
on to the optical disk; and after drawing operations are
commenced, the focus servo control is carried out based
upon the above-described adjustment.
[0003]
On the other hand, as to the optical disk on which
1

the drawing operation has been once carried out/
reflectance factors of a portion on the optical disk where
the drawing operation has been performed are changed,
but there are some possibilities that additional drawing
operations are wanted to be carried out. In this case,
in order to perform the focus gain control which is
required before the additional drawing operation is
carried out, the irradiation of the laser light for the
focus gain control must be performed in an area of the
optical disk in which the reflectance factors are slightly
changed. As a consequence, it is necessary to judge
whether a position of the optical disk where the laser
light is to be irradiated corresponds to a recorded area,
or an unrecorded area. Generally speaking, in the case
of such an optical disk on which data has been recorded,
since it is possible to judge whether a position of the
optical disk on which laser light is to be irradiated
corresponds to a data-recorded area, or a data-unrecorded
area, a focus servo gain can be controlled by judging
the data-unrecorded area.
[0004]
On the other hand, in the case of such an optical
disk where an image has been drawn, an area of the drawn
image includes a plenty of portions where lines have been
written and a plenty of portions where lines have not
been written. As a result, when a label surface of the
optical disk where the image has been drawn is scanned,
the portions which are not physically written and the
2

portions where the lines have been written are alternately
and frequently switched. As a result, the focus servo
gain cannot be controlled in a correct manner.
[0005]
SUMMARY OF THE INVENTION
The present, invention has been made by considering
the above-described problems, and therefore, an object
to provide an optical disk drawing apparatus, an optical
disk drawing system and an optical disk drawing method
capable of drawing an image on the label surface side
of an optical disk in an optimum focus servo gain even
in the case that the optical disk which has already been
drawn on the label surface side thereof.
[0006]
To solve the above-described problems,
(1) An optical disk drawing apparatus for drawing an
image on a drawing layer formed in an optical disk, the
apparatus comprising:
a rotating unit that rotates the optical disk;
an optical pickup that irradiates laser light onto
the optical disk and produces a light reception signal
based on reflection light reflected from the optical disk;
a feeding unit that relatively moves the optical
pickup with respect to the optical disk;
a focus servo controller that sets a focus servo
gain, controls a gain of a signal produced based on the
light reception signal according to the set focus servo
3

gain and perform a focus servo control so that a focal
point of the laser light output from the optical pickup
is focused on the drawing layer based on the
gain-controlled signal;
a judging unit that detects a position of the optical
pickup moved by the feeding unit and judges whether or
not an irradiation position of the laser light from the
optical pickup is located within a predetermined area
on the optical disk; and
a drawing controller that causes the focus servo
control to set the focus servo gain when a judgment result
made by the judging unit is positive, and permit a drawing
operation of irradiating the laser light onto the drawing
layer to form the image on the drawing layer when the
focus servo gain has been set by the focus servo controller
and the judgment result made by the judging unit is
negative.
(2) The apparatus according to (1), wherein the judging
unit stores area data indicative of the predetermined
area, and compares the stored area data and the detected
position of the optical pickup for the judging operation.
(3) The apparatus according to (1), wherein
the judging unit includes a reception unit that
receives area data indicative of the predetermined area,
and
the judging unit compares the area data received
4

by the reception unit and the detected position of the
optical pickup for the judging operation.
(4) The apparatus according to (1), wherein
the judging unit includes a readout unit that reads
area data indicative of the predetermined area from the
light reception signal output by the optical pickup; and
the judging unit compares the area data read by the
readout unit and the detected position of the optical
pickup for the judging operation.
(5) The apparatus according to (1) further comprising:
a storage that stores drawing data indicative of
the image;
a drawing judging unit that judges whether or not
the image data is to be drawn in the predetermined area
of the optical disk; and
a rewriting unit that corrects the image data so
that the corrected image data is not drawn in the
predetermined area when a judgment result made by the
drawing judging unit is positive.
(6) Amethod of drawing an image on a drawing layer formed
in an optical disk, the method comprising:
rotating the optical disk;
irradiating laser light onto the optical disk to
produce a light reception signal basedon reflection light
reflected from the optical disk;
5

first relatively moving the optical pickup with
respect to the optical disk so that an irradiation position
of the laser light from the optical pickup is located
within a predetermined area on the optical disk;
after the first moving, setting a servo control gain;
after the setting, second relatively moving the
optical pickup with respect to the optical disk $o that
the irradiation position of the laser light from the
optical pickup is not located within the predetermined
area on the optical disk;
after the second moving, controlling a gain of a
signal produced based on the light reception signal
according to the set focus servo gain and performing a
focus servo control so that a focal point of the laser
light output from the optical pickup is focused on the
drawing layer based on the gain-controlled signal;
after the controlling, permitting a drawing
operation of irradiating the laser light onto the drawing
layer to form the image on the drawing layer.
(7) An optical disk drawing system comprising:
an optical disk including a drawing layer in which
an image is to be drawn;
a rotating unit that rotates the optical disk;
an optical pickup that irradiates laser light onto
the optical disk and produces a light reception signal
based on reflection light reflected from the optical disk;
a feeding unit that relatively moves the optical
6

pickup with respect to the optical disk;
a focus servo controller that sets a focus servo
gain, controls a gain of a signal produced based on the
light reception signal according to the set focus servo
gain, and performs a focus servo control so that a focal
point of the laser light output from the optical pickup
is focused on the drawing layer based on the
gain-controlled signal;
a judging unit that detects a position of the optical
pickup moved by the feeding unit and judges whether or
not an irradiation position of the laser light from the
optical pickup is located within a predetermined area
on the optical disk; and
a drawing controller that causes the focus servo
control to control the focus servo gain when a judgment
result made by the judging unit is positive, and permit
a drawing operation of irradiating the laser light onto
the drawing layer to form the image when the focus servo
gain has been set by the focus servo controller and the
judgment result made by the judging unit is negative.
(8) The system according to (7), wharain
the optical disk includes an automatic adjusting
area as the predetermined area of the optical disk and
a drawing area where the image is drawn, and
a structure of the automatic adjusting area is
identical to a structure of the drawing area.
7

(9) The system according to (8), wherein
the optical disk includes a data recording layer
for recording data,
a groove is formed on the data recording layer.
(10) The system according to (9) further comprising a
tracking servo that performs a tracking servo control
is performed for the data record ing layer having the groove
when the data is recorded in the data recording layer,
and does not perform the tracking servo control for the
drawing layer having no groove when the image is drawn
in the drawing layer.
[0011]
In accordance with the present invention, even with
respect to such an optical disk which has been drawn on
the label surface side thereof, it is possible to provide
the optical disk drawing apparatus capable of drawing
on the label surface side thereof in the optimum focus
servo gain.
[0039]
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a plan view of an optical disk, according
to an embodiment of the present invention, as viewed from
a label surface of the optical disk.
Fig. 2 is a sectional view of either a drawing area
or an automatic adjusting area of the optical disk
according to the embodiment.
Fig. 3 is a sectional view of an information area
8

of the optical disk according to the embodiment.
Fig. 4 is a block diagram for showing an arrangement
of an optical disk drawing apparatus according to the
embodiment.
Fig. 5 is a block diagram for showing an arrangement
of a focus servo control employed in the optical disk
drawing apparatus according to the embodiment.
Fig. 6 is an explanatory diagram for explaining
signals in the focus servo control.
Fig. 7 is a sectional view of either a drawing area
or an automatic adjusting area of an optical disk according
to a modification 2.
Fig. 8 is a block diagram for showing an arrangement
of a focus servo control employed in an optical disk
drawing apparatus according to a modification 4.
[0012]
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Next, a description is made of an embodiment
according to the present invention.
[0013]
EMBODIMENT
An optical disk drawing apparatus 1 according to
the present embodiment has a function capable of drawing
an image on a label surface side of an optical disk 100
thereby a user can visually recognize the drawn image.
In the following description/ the optical disk 100 is
firstly described, and thereafter, the optical disk
drawing apparatus 1 is described.
9

[0014]
Fig. 1 is a plan view of the optical disk 100 according
to the present embodiment, as viewed from a label surface
"LS" thereof . The optical disk 100 is, for instance, such
a visible image recordable disk in which an image can
be drawn on a side of a label surface LS of a general-purpose
disk, In the present embodiment, it is assumed that the
optical disk 100 is a DVD-R, but may be alternatively
realized as such an optical disk as a CD-R, and the like.
[0015]
As indicated in Fig. 1, the optical disk 100
includes: an information area 102 (areas having radius
of 22 mm to 24 mm) ; an automatic adjusting area 103 (areas
having radius of 24 mm to 25 mm) ; and a drawing area 104
(areas having radius of 25 mm to 58.2 mm) on the side
of the label surface LS from a center hole 101 of the
optical disk 100 toward an outer circumference thereof,
information about the optical disk 100 and the like are
stored in the information area 102. When a focus servo
gain adjustment is carried out, laser light is irradiated
onto the automatic adjusting area 103. An image is drawn
on the drawing area 104. It should be understood that
in the present embodiment, since a structure of the
automatic adjusting area 103 is identical to a structure
of the drawing area 104, the automatic adjusting area
103 may be drawn, but has been discriminated as an area
which is not drawn.
[0016]
10

Fig. 2 is a sectional view for showing both the
automatic adjusting area 103 and the drawing area 104
of the optical disk 100 . As shown in Fig. 2, the sectional
structure of the optical disk 100 is formed by sequentially
arranging a polycarbonate layer 111, a drawing layer 112,
a reflection layer 113, an adhesive layer 114, another
reflection layer 115, a data recording layer 116, and
another polycarbonate layer 117 from, the label surface
LS toward a recording surface "DS." While a thickness
of the optical disk 100 is approximately 1.2 mm, each
of the polycarbonate layer 111 and the polycarbonate layer
117 occupies approximately 0.6 mm, so that a thickness
from the drawing layer 112 up to the data recording layer
116 is a very short distance of "d", as compared with
the entire thickness of approximately 1.2 nun. A
helical-shaped groove (guide groove) 118 is formed on
a side of a recording surface "DS" of the data recording
layer 116.
[0017]
The drawing layer 112 and the data recording layer
116 are coloring matter layers formed by a substance which
is discolored when laser light having strength higher
than, or equal to a predetermined strength is irradiated
onto the coloring matter layers. When a drawing operation
is carried out, laser light is focused onto the drawing
layer 112 based upon reflection light from the reflection
layer 113 . Then, when the laser light having the strength
higher than, or equal to the predetermined strength, an
11

area of the drawing layer 112 onto which the laser light
is irradiated is discolored. An image which can be
visually recognized by a user is formed by the discolored
area and another area which is not disclosed. Similarly,
when a data recording operation is carried out, laser
light is focused onto the data recording layer 116 based
upon reflection light from the reflection layer 115 so
as to record data along the groove 118. In the case that
recorded data is read out, a laser light having a strength
lower than a predetermined strength which is lower than
that of the data recording operation is irradiated along
the groove 118, and then, strengths of reflection light
are sensed so as to realize the data recording operation.
[0018]
Fig. 3 is a sectional view for showing the
information area 102 of the optical disk 100. As
indicated in Fig. 3, in addition to the sectional
structures of the automatic adjusting area 103 and the
drawing area 104 of the above-described optical disk 100,
a pre-pit 119 is formed on the side of the label surface
LS of the drawing area 112. Data which indicates that
the optical disk 100 is a visible image recordable disk
capable of drawing on the side of a label surface thereof
has been recorded on the pre-bit 119.
[0019]
Next, a description is made of the optical disk
drawing apparatus 1. Fig. 4 is a block diagram for showing
an arrangement of the optical disk drawing apparatus 1
12

in the case that the optical disk 100 is loaded on the
optical disk drawing apparatus 1.
[0020]
In the optical disk drawing apparatus 1, the optical
disk 100 is rotated by a spindle motor 11. A spindle servo
12 controls rotations of the spindle motor 11 in such
a manner that a linear velocity is constant: (namely, CLV
control) when both a recording operation and a reproducing
operation are carried out, whereas a rotation number
thereof is constant (namely, CAV control) when a drawing
operation is carried out. An optical pickup 14 is
transported by a feeding mechanism 16 along a radial
direction (right and left directions, as viewed in this
drawing) of the optical disk 100 so as to irradiate laser
light 13 onto the optical disk 100. The feeding mechanism
16 is constructed of a feeding screw and the like/ which
is driven by a stepping motor 15. Then, a light reception
signal produced based upon reflection light reflected
from the optical disk 100 is output to respective circuits
of the optical disk drawing apparatus 1. A motor driver
17 drives the stepping motor 15 in response to an
instruction of a system control unit 19. Since the system
control unit 19 has stored thereinto the area of the
automatic adjusting area 103, the system control unit
19 can judge whether or not a present position corresponds
to such aposition where the laser light 13 from the optical
pickup 14 is to be irradiated onto the automatic adjusting
area 103.
13

[0021]
A focus servo 19 performs a focus servo control
during a data recording operation, a reproducing
operation, and a drawing operation in order to control
a focus position of an objective lens of the optical pickup
14. A detailed operation of the focus servo 10 will be
described later.
[0022]
A tracking servo 20 performs a tracking servo control
of the optical pickup 14 based upon an instruction issued
from the system control unit 19 and the light reception
signal from the optical pickup 14 when the data recording
operation and the reproducing operation are carried out.
It should be noted that the tracking servo control is
turned off when the drawing operation is carried out.
An ALPC (Automatic Laser Power Control) circuit 21
controls strength of the laser light 13 when a laser driver
22 drives a laser diode of the optical pickup 14 during
the data recording operation, the reproducing operation,
and the drawing operation in response to both the
instruction issued from the system control unit 19, and
the light reception signal derived from the optical pickup
14.
[0023]
An encoder 23 encodes recording data to obtain a
format in accordance with the type of the optical disk
100 when the data recording operation is carried out.
In the present embodiment, since the type of the optical
14

disk 100 is a DVD-R, the encoder 23 performs an 8-to-16
modulating operation. The laser driver 22 modulates the
laser light 13 in response to the encoded recording data,
and records the encoded recording data by discoloring
the data recording layer 116 of the optical disk 100.
On the other hand, when the drawing operation is carried
out, the encoder 23 produces a pulse signal (will be
referred to as "drawing signal" hereinafter), the duty
ratio of the pulse signal being changed in response to
gradation data of a pixel which constitutes drawing data.
The laser driver 22 modulates the laser light 13 based
upon the drawing signal so as to perform a drawing
operation based on monochromatic multi-gradation by
discoloring the drawing layer 112 of the optical disk
100. A decoder 25 performs an 8-to-16 demodulating
operation with respect to the light reception signal
derived from the optical pickup 14 so as to reproduce
data, and then, transmits the reproduced data via an
interface 10 to a host apparatus 200 during the data
reproducing operation.
[0024]
The host apparatus 200 transmits an instruction so
as to cause the optical disk drawing apparatus 1 to perform
any one of the data recording operation, the data
reproducing operation, and the drawing operation. Also,
the host apparatus 200 transmits an instruction issued
from an operator to the optical disk drawing apparatus
1. The instruction is transmitted via the interface 10
15

to the system control unit 19. The system control unit
19 executes corresponding operations with respect to the
respective circuits of the optical disk drawing apparatus
1 in response to the transmitted instruction. The host
apparatus 200 stores either drawing data of an image or
recording data via the interface 10 into a buffer memory
24 . The drawing data of the image is drawn in the drawing
layer 112 formed on the side of the label surface LS of
the optical disk 100, whereas the recording data is
recorded on the data recording layer 116 formed on the
side of the recording surface DS thereof. Either the
drawing data or the recording data is once stored in the
buffer memory 24, and thereafter, is read therefrom so
as to be supplied to the encoder 23.
[0025]
Next, a description is made of an arrangement of
the above-described focus servo 18. Fig. 5 is a block
diagram for showing the arrangement of the focus servo
18. A focus error producing circuit 181 produces a focus
error signal in response to a light reception signal output
from the optical pickup 14. A focus error amplifier 182
is a gain control circuit which controls a gain of a focus
error signal based upon a focus servo gain, and sets the
focus servo gain required to perform a stable focus servo
control under control of the system control unit 19. An
equalizer 183 performs a phase compensating operation
with respect to the focus error signal whose gain has
been set by the focus error amplifier 182, and then,
16

outputs the phase-compensated focus error signal as a
focus error control signal. A triangular wave generating
circuit 184 is a circuit for outputting a triangular wave
signal. A loop switch SW is a switch which is operated
in order that any one of the focus error control signal
output from the equalizer 183 and the triangular wave
signal output from the triangular wave generating circuit
184 is entered to a driving circuit 185. The driving
circuit 185 moves the objective lens of the optical pickup
14 in response to the entered signal. Concretely speaking,
when the input signal is the focus error control signal,
the driving circuit 185 controls the optical pickup 14
in such a manner that the objective lens of the optical
pickup 14 is moved along a direction capable of canceling
a focus error, namely, the objective lens is focused onto
the drawing layer 112 during the drawing operation. When
the input signal is the triangular wave signal, the driving
circuit 165 controls the optical pickup 14 in such a manner
that the focal position of the objective lens is vibrated
based upon the waveform of the triangular wave signal.
An amplitude measuring device 186 detects amplitude of
the focus error signal and outputs the detected amplitude
to the system control unit 19.
[0026]
Referring now to Fig. 4, Fig. 5, and Fig. 6, a
description is made of operations in such a case that
the optical disk drawing apparatus 1 draws on the optical
disk 100 . Firstly, the host apparatus 200 transmits both
17

an instruction and drawing data with respect to the
interface 10 of the optical disk drawing apparatus 1 in
order to perform a drawing operation for the optical disk
100. The interface 10 outputs the instruction
transmitted from the host apparatus 200 to the system
control unit 19, and stores the drawing data in the buffer
memory 24.
[0027]
Subsequently, the optical disk 100 is loaded on the
optical disk drawing apparatus 1. When the optical disk
100 is loaded/ the spindle motor 12 is controlled by the
system control unit 19 in order that the rotation speed
of the spindle motor 11 is controlled to become constant
(namely, CAV control) . Then, the system control unit 19
controls the motor driver 17 in such a manner that the
stepping motor 15 causes the feeding mechanism 16 to move
the position of the optical pickup 14 so as to locate
such a position where the laser light 13 is to be irradiated
to the automatic adjusting area 103 of the optical disk
100 . This control condition may be judged based upon the
move distance of the optical pickup 14. The system
control unit 19 controls the ALPC circuit 21 in order
that strength of the laser light 13 becomes equal to such
strength during the reproducing operation (namely,
strength of laser light 13 by which drawing layer 112
is not discolored). Then, the tracking servo 20 is
controlled to be turned off by the system control unit
19.
18

[0028]
Next, a setting operation of a focus servo gain with
respect to the focus error amplifier 182 of the focus
servo 18 will now be explained with reference to Fig.
5 and Fig.6. Firstly, the system control unit 19 switches
the loop switch SW to such a switching mode as indicated
by a broken line of Fig. 5 so as to connect the triangular
wave generating circuit 184 to the driving circuit 185.
Then, such a triangular wave signal as shown in Fig. 6
is entered to the driving circuit 185. As a result, the
driving circuit 185 performs a control operation as
follows: That is, the objective lens of the optical
pickup 14 is moved close to, or separated from the optical
disk 100 at a constant speed so as to change the position
of the focal point, so that the focal point of the objective
lens passes through the drawing layer 112.
[0029]
As represented in Fig. 6, a focus error signal is
changed in an S-shaped form (will be referred to as "S
curve" hereinafter) before and after the focal point of
the objective lens is focused on the drawing layer 112.
At this time, at timing when the S curve crosses a zero
point, the focal point of the objective lens is under
just focusing condition with respect to the drawing layer
112. Then, the focus error signal is output to the
amplitude measuring device 186, so that the amplitude
measuring device 186 measures an amplitude of the S curve
and outputs the measured amplitude to the system control
19

unit 19. In this case, it is so assumed that apeak voltage
of the amplitude of the S curve is "Vp."
[0030]
Next, the system control unit 19 sets the focus servo
gain of the focus error amplifier 182 in such a manner
that a peak voltage of an amplitude of the focus error
signal which is output from the focus error amplifier
182 becomes a predetermined voltage "Vc", while the gain
of the focus error signal has been controlled. In other
words, the system control unit 19 sets the focus servo
gain so that the focus error amplifier 182 amplifies the
focus error signal by multiplied by Vc/Vp.
[0031]
Then, the system control unit 19 switches the loop
switch SW to such a switching mode as indicated by a solid
line of Fig. 5 so as to connect the equalizer 183 to the
driving circuit 185. As a result, in the focus servo 18,
a focus loop is constructed in conjunction with the optical
pickup 14. Then, the system control unit 19 continuously
controls the position of the objective lens of the optical
pickup 14 based upon a light reception signal derived
from the optical pickup 14 during a drawing operation
by performing a feedback control operation in order that
the focal point of the objective lens is focused on the
drawing layer 112. The setting operation of the focus
servo gain performed in the focus servo 18 has been
explained.
[0032]
20

Referring back to Fig. 4, a description as to the
drawing operation with respect to the optical disk 100
will be continued. The system control unit 19 controls
the motor driver 11 in order that the stepping motor 15
moves the position of the optical pickup 14 by driving
the feeding mechanism 16, so that the position where the
laser light 13 is irradiated is located in the drawing
area 104 of the optical disk 100. This positioning
control may be judged based upon the travel distance of
the optical pickup 14. Also, the system control unit 19
controls the ALPC circuit 21 in such a manner that strength
of the laser light 13 nay become a strength for the drawing
operation (namely, strength of laser light 13 by which
drawing layer 112 is discolored) . The drawing data which
have been stored in the buffer memory 24 are sequentially
read out therefrom, and the encoder 23 produces drawing
signals from the read drawing data and then outputs the
produced drawing signals to the ALPC circuit 21. The ALPC
circuit 21 modulates the laser light 13 based upon the
drawing signals, and controls the laser driver 22 in such
a manner that an image is drawn on the optical disk 100.
As previously described, the optical disk drawing
apparatus 1 may perform a desirable drawing operation
with respect to the optical disk 100.
[0033]
At this time, in such a case that after the drawing
operation has been carried out with respect to the drawing
layer 112 of the optical disk 100, an additional drawing
21

operation is wanted to be furthermore carried out, the
advantage of the present embodiment can be considerably
achieved. In other words, in the conventional optical
disk drawing apparatus, since the item which has already
been drawn on the optical disk is the image, the
image-recorded area and the image-unrecorded area are
frequently changed. As a result, the reflection light
of the laser light 13 is not stable, so that the focus
servo gain can be hardly controlled in the correct manner.
However, as previously explained in the present
embodiment, the automatic adjusting area 103 where the
drawing operation is not carried out is provided in the
optical disk 100, and the laser light 13 is irradiated
onto the formed automatic adjusting area 103 so as to
control the focus servo gain, thereby the stable focus
servo control can be carried out.
[0034]
While the embodiment of the present invention has
been described, the present invention may be
alternatively embodied in the following various modes.
[0035]
MODIFICATION 1
In the above-described embodiment, as shown in Fig.
1, the automatic adjusting area 103 has been previously
provided between the information area 102 and the drawing
area 104. Alternatively, the automatic adjusting area
103 can be formed at an arbitrary place of the optical
disk 100, for example, can be provided in the vicinity
22

of the outermost circumferential portion thereof. In
this alternative case, the information as to the automatic
adjusting area 103, which is stored in the information
area 102, is read, so that the system control unit 19
can recognize this automatic adjusting area 103 based
upon the read information. Also, the information of the
automatic adjusting area 103 may be output from the host
apparatus 200 to the system control unit 19 based upon
an operation of the operator, and then, the system control
unit 19 recognizes the automatic adjusting area 103 by
receiving the output information. It should also be
understood that as to the width of the automatic adjusting
area 103, any sizes of widths maybe alternatively employed
as long as a width capable of controlling the focus servo
gain is secured. In this alternative width case, a
freedom degree of such an area capable of drawing an image
can be increased.
[0036]
MODIFICATION 2
In the above-described embodiment, when the drawing
operation is carried out on the drawing layer 112, the
laser light 13 can be irradiated from the side of the
label surface LS. Alternatively, the laser light 13 may
be irradiated from the side of the recoding surface DS
so as to draw the drawing layer 112. In this alternative
case, as indicated in Fig. 7, a sectional structure of
the drawing area 104 of the optical disk 100 is realized
by sequentially arranging the polycarbonate layer 111,
23

the reflection layer 113, the drawing layer 112, the
adhesive layer 114, a semi-transparent reflection layer
120, the data recording layer 116, and the polycarbonate
layer 117 along a direction from the label surface LS
toward the recording surface DS. In this alternative case,
a difference between the above-described alternative
optical disk and the optical disk 100 shown in Fig. 2
is a positional relationship of the reflection layer 113.
Then, in this alternative optical disk, the focus servo
18 may be controlled under control of the system control
unit 19 in such a manner that the focal point of the
objective lens of the optical pickup 14 is focused on
the data recording layer 116 when the data reproducing
operation and the data recording operation are carried
out, whereas this focal point is focused on the drawing
layer 112 when the image drawing operation is carried
out.
[0037]
MODIFICATION 3
In the above-described embodiment, no drawing
operation has been carried out with respect to the
automatic adjusting area 103 of the optical disk 100.
Alternatively/ in the case that such a data to be drawn
in the automatic adjusting area 103 has been contained
in the drawing data transmitted from the host apparatus
200 during the drawing operation, the encoder 23 rewrites
this data into such a drawing data which is not written
in the automatic adjusting area 103, and thereafter,
24

produces a drawing signal. In this alternative rewriting
operation of the drawing data, the drawing data is
rewritten in such a manner that an image to be positioned
in the automatic adjusting area 103 is deleted. Also,
the drawing data may be alternatively rewritten in such
a manner that magnification of this image is changed so
as to store the image within the drawing area 104, so
that the image is not present in the automatic adjusting
area 103. In these alternative cases, even when the
drawing data transmitted from the host apparatus 100
corresponds to such a data to be drawn in the automatic
adjusting area 103, the drawing operation for the
automatic adjusting area 103 may not be permitted by the
optical disk drawing apparatus 1.
[0038]
MODIFICATION 4
In the above-described embodiment, the focus servo
18 has employed such an arrangement as shown in Fig. 5.
Alternatively, even when the focus servo 18 may employ
another arrangement as represented in Fig. 8, this focus
servo 18 may control the focus servo gain in a stable
manner. A description is made of the alternative
arrangement shown in Fig. 8 employed in the focus servo
18 . It should also be understood that the same reference
numerals shown in Fig. 5 will be employed as those for
denoting the same structural elements indicated in Fig.
8, and therefore, detailed descriptions thereof will be
omitted. A disturbance signal generating circuit 187
25

generates a disturbance signal having a frequency of
several KHz. Then, the generated disturbance signal is
injected via an adder 188 into a focus error signal output
from the focus error producing circuit 181, and thereafter,
the added focus error signal is output to the focus error
amplifier 182. Then, the equalizer 183 produces a focus
error control signal based upon the focus error signal
into which the disturbance signal has been injected . Then,
the driving circuit 185 controls the optical pickup 14
based upon the produced focus error control signal. A
light recaption signal output from the optical pickup
14 is entered to the focus error producing circuit 181,
so that the loop is circulated. A BPF (bandpass filter)
189 derives the disturbance signal component from the
focus error signal which has been circulated within the
loop, and a phase difference measuring circuit 190
measures a phase difference between the disturbance
signal output from the disturbance signal generating
circuit 187, and the disturbance signal derived from the
focus error signal. Then, the system control unit 19 sets
the focus servo gain of the focus error amplifier 183
in order to become a predetermined phase difference. As
previously described, even when any type of focus servo
has the above-described arrangement which is different
from that of the above-explained embodiment, if such a
focus servo control employs a method capable of
irradiating the laser light 13 onto the automatic
adjusting area 103 and capable of controlling a focus
26

servo gain based upon a light reception signal output
from tha optical pickup 14, then a similar advantage to
that of the above-described embodiment may be achieved
in any types of focus servo control arrangements.
27

WHAT IS CLAIMED IS:
1. An optical disk drawing apparatus for drawing an
image on a drawing layer formed in an optical disk, the
apparatus comprising:
a rotating unit that rotates the optical disk;
an optical pickup that irradiates laser light onto
the optical disk and produces a light reception signal
based on reflection light reflected from the optical disk;
a feeding unit that relatively moves the optical
pickup with respect to the optical disk;
a focus servo controller that sets a focus servo
gain, controls a gain of a signal produced based on the
light reception signal according to the set focus servo
gain and perform a focus servo control so that a focal
point of the laser light output from the optical pickup
is focused on the drawing layer based on the
gain-controlled signal;
a judging unit that detects a position of the optical
pickup moved by the feeding unit and judges whether or
not an irradiation position of the laser light from the
optical pickup is located within a predetermined area
on the optical disk; and
a drawing controller that causes the focus servo
control to set the focus servo gain when a judgment result
made by the judging unit is positive/ and permit a drawing
operation of irradiating the laser light onto the drawing
layer to form the image on the drawing layer when the
focus servo gain has been set by the focus servo controller
28

and the judgment result made by the judging unit is
negative.
2. The apparatus according to claim 1, wherein the
judging unit stores area data indicative of the
predetermined area, and compares the stored area data
and the detected position of the optical pickup for the
judging operation.
3. The apparatus according to claim 1, wherein
the judging unit includes a reception unit that
receives area data indicative of the predetermined area,
and
the judging unit compares the area data received
by the reception unit and the detected position of the
optical pickup for the judging operation.
4. The apparatus according to claim 1, wherein
the judging unit includes a readout unit that reads
area data indicative of the predetermined area from the
light reception signal output by the optical pickup; and
the judging unit compares the area data read by the
readout unit and the detected position of the optical
pickup for the judging operation.
5. The apparatus according to claim 1 further
comprising:
a storage that stores drawing data indicative of
29

the image;
a drawing judging unit that judges whether or not
the image data is to be drawn in the predetermined area
of the optical disk; and
a rewriting unit that corrects the image data so
that the corrected image data is not drawn in the
predetermined area when a judgment result made by the
drawing judging unit is positive.
6. A method of drawing an image on a drawing layer formed
in an optical disk, the method comprising:
rotating the optical disk;
irradiating laser light onto the optical disk to
produce a light reception signal based on reflection light
reflected from the optical disk;
first relatively moving the optical pickup with
respect to the optical disk so that an irradiation position
of the laser light from the optical pickup is located
within a predetermined area on the optical disk;
after the first moving, setting a servo control gain;
after the setting, second relatively moving the
optical pickup with respect to the optical disk so that
the irradiation position of the laser light from the
optical pickup is not located within the predetermined
area on the optical disk;
after the second moving, controlling a gain of a
signal produced based on the light reception signal
according to the set focus servo gain and performing a
30

focus servo control so that a focal point of the laser
light output from the optical pickup is focused on the
drawing layer based on the gain-controlled signal;
after the controlling/ permitting a drawing
operation of irradiating the laser light onto the drawing
layer to form the image on the drawing layer.
7, An optical disk drawing system comprising:
an optical disk including a drawing layer in which
an image is to be drawn;
a rotating unit that rotates the optical disk;
an optical pickup that irradiates laser light onto
the optical disk and produces a light reception signal
based on reflection light reflected from the optical disk;
a feeding unit that relatively moves the optical
pickup with respect to the optical disk;
a focus servo controller that sets a focus servo
gain, controls a gain of a signal produced based on the
light reception signal according to the set focus servo
gain, and performs a focus servo control so that a focal
point of the laser light output from the optical pickup
is focused on the drawing layer based on the
gain-controlled signal;
a judging unit that detects a position of the optical
pickup moved by the feeding unit and judges whether or
not an irradiation position of the laser light from the
optical pickup is located within a predetermined area
on the optical disk; and
31

a drawing controller that causes the focus servo
control to control the focus servo gain when a judgment
result made by the judging unit is positive, and permit
a drawing operation of irradiating the laser light onto
the drawing layer to form the image when the focus servo
gain has been set by the focus servo controller and the
judgement result made by the judging unit is negetive.
8. The system according to claim 7, wherein
the optical disk includes an automatic adjusting
area as the predetermined area of the optical disk and
a drawing area where the image is drawn, and
a structure of the automatic adjusting area is
identical to a structure of the drawing area.
9. The system according to claim 8, wherein
the optical disk includes a data recording layer
for recording data,
a groove is formed on the data recording layer.
32
10. The system according to claim 9 further comprising
a tracking servo that performs a tracking servo control
is performed for the data recording layer having the groove
when the data is recorded in the data recording layer,
and does not perform the tracking servo control for the
drawing layer having no groove when the image is drawn
in the drawing layer.

In the optical disk drawing apparatus of the present
invention, an automatic adjusting area where the drawing
operation is not carried out is provided in the optical
disk, laser light is irradiated onto the formed automatic
adjusting area so as to control the focus serve gain,
so that a stable focus servo control can be carried out.