U.S. patent application number 12/204039 was filed with the patent office on 2009-01-01 for information recording apparatus and information recording method.
This patent application is currently assigned to Hitachi, Ltd.. Invention is credited to Kouji Minabe, Hideo Nishijima, Jun Ohya, Hiroaki Ono.
Application Number | 20090003160 12/204039 |
Document ID | / |
Family ID | 19112719 |
Filed Date | 2009-01-01 |
United States Patent
Application |
20090003160 |
Kind Code |
A1 |
Nishijima; Hideo ; et
al. |
January 1, 2009 |
Information Recording Apparatus and Information Recording
Method
Abstract
An information recording apparatus such as an optical disc that
can avoid an unrecordable condition between a power-on operation
and an available state for recording thereby to solve a problem
that an image taking chance is missed in a recording step, wherein
its constitution is such that: receiving a command to turn on the
apparatus after switching, a system controller drives a
power-supply circuit to activate a drive controller and a memory
controller; if the optical disc is not replaced while in power-off
operation by a sub-battery, the system controller issues a request
for high-speed activation, based on information stored in an
EEPROM, to the drive controller, and drives plural drive control
units one after another thereby to establish an activation period
confirmedly, allowing the memory controller to accept a request for
a recording start from the system controller without waiting for a
report of activation completion to be issued by the drive
controller.
Inventors: |
Nishijima; Hideo;
(Hitachinaka, JP) ; Ono; Hiroaki; (Mito, JP)
; Minabe; Kouji; (Hitachiohta, JP) ; Ohya;
Jun; (Mito, JP) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER, EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Hitachi, Ltd.
Tokyo
JP
|
Family ID: |
19112719 |
Appl. No.: |
12/204039 |
Filed: |
September 4, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10087514 |
Feb 28, 2002 |
7424200 |
|
|
12204039 |
|
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Current U.S.
Class: |
369/47.28 ;
386/E5.072; G9B/20.009; G9B/21.02; G9B/27.05; G9B/27.051;
G9B/27.052; G9B/5.033 |
Current CPC
Class: |
H04N 5/772 20130101;
G11B 27/329 20130101; G11B 2220/2562 20130101; G11B 21/106
20130101; H04N 9/8047 20130101; G11B 2220/218 20130101; G11B 20/10
20130101; H04N 5/85 20130101; G11B 27/34 20130101; H04N 9/8042
20130101; H04N 9/7921 20130101; G11B 2020/10537 20130101; G11B 7/00
20130101; G11B 2220/2575 20130101; G11B 27/36 20130101; G11B
2220/216 20130101 |
Class at
Publication: |
369/47.28 ;
G9B/5.033 |
International
Class: |
G11B 5/09 20060101
G11B005/09 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 2001 |
JP |
2001-290411 |
Claims
1. An information recording/reproduction apparatus comprising: an
information recording means for recording information onto a
recording medium; a step-order control means for controlling a
transition to a recordable state in which the information recording
means is capable of recording information onto the recording
medium; a power-supply means for supplying power to at least the
information recording means; and a buffer means for storing the
information to be recorded onto the recording medium, wherein,
during a period of time starting with an operation to turn on the
power-supply means and ending with an operation carried out by the
step-order control means to put the information recording means in
the recordable state, an operation to store the information to be
recorded onto the recording medium into the buffer means is started
and, as the amount of the information stored in the buffer means
reaches a predetermined quantity after the information recording
means has entered the recordable state, an operation to record the
information onto the information recording means is commenced.
2. The apparatus according to claim 1, wherein the amount of
information stored into the buffer means per unit time is smaller
than the amount of information recorded onto the recording medium
per same unit time.
3. The apparatus according to claim 1, further comprising a
notification means for informing the user that an information
recording operation can be started and a command detection means
for detecting a command entered by the user to start the
information recording operation, wherein before an operation to
store information into the buffer means is started, the
notification means informs a user that an information recording
operation can be started and, as the command detection means
detects a command entered by the user to start the information
recording operation, the operation to store information into the
buffer means is started.
4. The apparatus according to claim 1, further comprising a means
for monitoring operations to mount and dismount the disc recording
medium on and from the information recording apparatus wherein:
assuming that a first transition controlled by the step-order
control means to the recordable state after the mounting operation
is detected by the monitoring means, an operation to store
information to be recorded into the buffer means is to be in
available state after the information recording means enters the
recordable state; and assuming that, after completion of the
recording operation, no mounting nor demounting operation was
detected by the monitoring means until turning on again the
power-supply means from turning off the power-supply means, an
operation to store information to be recorded into the buffer means
is to be in available state before the information recording means
enters the recordable state.
5. The apparatus according to claim 1, wherein the recording medium
is an optical disc; and the information recording means is an
optical disc information recording means comprising: a
laser-emission control means for radiating a laser beam to the
optical disc; a lens for converging the laser beam; a servo control
means for controlling the position of the lens; a modulation means
for carrying out an operation to record information read out from
the buffer means onto the optical disc through conversion of the
information into an emission power of the laser-emission control
means; and a demodulation means for reading out information from
the optical disc with the emission power of the laser-emission
control means kept at a fixed value, and wherein the transition to
a recordable state allowed by the step-order control means,
comprises some or all of the following steps of: emitting a laser
beam by the laser-emission control means; servo controlling by the
servo control means to control the position of the lens so as to
converge the laser beam on any one of tracks created on the surface
of the optical disc; identifying the type of the optical disc: by a
characteristic of the laser beam reflected by the surface of the
optical disc; or by reading out information recorded in advance on
the optical disc and demodulating the read-out information by using
the demodulation means; finding an optimum power of the laser beam
for each optical disc, used for recording, by varying the emission
power for each optical disc; searching the optical disc for a
recordable position; and placing the lens at the thus searched
recordable position.
6. The apparatus according to claim 5, further comprising a storage
means enabling data to be stored therein even if the power-supply
means is cut off, wherein the apparatus is constituted such that:
any one, any combination or all of a result of identification of
the type of the optical disc, the optimum value of the laser beam
used for recording, and the recordable position information on the
optical disc is stored in the storage means; if an operation to
turn on again the power-supply means is carried out after an
operation carried out to turn off the power-supply means, any one,
any combination or all of the result of identification of the type
of the optical disc, the optimum value of the laser beam used for
recording, and the recordable position information on the optical
disc is read out from the storage means; and some of the steps
composing the transition to a recordable state through control
executed by the step-order control means, is eliminated due to
availability of one, any combination or all of those.
7. The apparatus according to claim 1, further comprising a means
for sensing an image signal, a means for displaying the image
sensing signal, and a means for encoding the image taking signal,
wherein the information to be recorded onto the recording medium is
a signal outputted by the image-signal encoding means of the image
sensing signal.
8. An information recording/reproduction apparatus comprising: a
means for recording information onto a recording medium; a buffer
means for storing the information to be recorded onto the recording
means; a step-order control means for controlling a transition
where the information recording means is to be available for
recording information onto the recording medium; and a means for
supplying power to the information recording means, the buffer
means, and the step-order control means, and the apparatus is
constituted such that: it has a first step and a second step during
a period from the time of a turn-on of the power-supply means to
the time of availability for recording information onto the
recording medium, wherein: if the information recording means is
put in recordable state by carrying out the first step, after the
first step is completed, an operation to store the information to
be recorded onto the recording medium into the buffer means is
started and, as the amount of the information stored in the buffer
means reaches a proper quantity, the information recording means
starts an operation to record the information from the buffer means
onto the information recording means; and if the information
recording means is put in recordable state by carrying out the
second step, on the other hand, an operation to store the
information to be recorded onto the recording medium into the
buffer means is started without waiting for the second step to be
started or completed and, as the information recording means enters
the recordable state and the amount of the information stored in
the buffer means reaches a proper quantity, the information
recording means starts an operation to record the information from
the buffer means onto the information recording means.
9. The apparatus according to claim 8, wherein the amount of
information stored into the buffer means per unit time is smaller
than the amount of information recorded onto the recording medium
per same unit time.
10. The apparatus according to claim 8, further comprising a
notification means for informing the user that an information
recording operation can be started and a command detection means
for detecting a command entered by the user to start the
information recording operation, wherein the apparatus is
constituted such that if the information recording means is put in
recordable state by carrying out the first step, the notification
means informs the user that the information recording operation can
be started when the information recording means enters the
recordable state; if the information recording means is put in
recordable state by carrying out the second step, on the other
hand, the notification means informs the user that the information
recording operation can be started without waiting for the second
step to be started or completed; and in either case, if the command
detection means detects a command entered by the user to start the
information recording operation after the notification means
informs the user that the information recording operation can be
started, an operation to store the information to be recorded onto
the recording medium into the buffer means is started.
11. The apparatus according to claim 8, further comprising a means
for monitoring operations to mount and dismount the disc recording
medium on and from the information recording apparatus wherein the
apparatus is constituted such that: assuming that a first
transition to the recordable state after the mounting operation is
detected by the monitoring means, an operation to store information
to be recorded into the buffer means is allowed to be in available
state by the first step; and assuming that, after completion of the
recording operation, no mounting nor demounting operation was
detected by the monitoring means until turning on again the
power-supply means from turning off the power-supply means, an
operation to store information to be recorded into the buffer means
is allowed to be in available state by the second step.
12. The apparatus according to claim 8, wherein the recording
medium is an optical disc; and the information recording means is
an optical disc information recording means comprising: a
laser-emission control means for radiating a laser beam to the
optical disc; a lens for converging the laser beam; a servo control
means for controlling the position of the lens; a modulation means
for carrying out an operation to record information read out from
the buffer means onto the optical disc through conversion of the
information into an emission power of the laser-emission control
means; and a demodulation means for reading out information from
the optical disc with the emission power of the laser-emission
control means kept at a fixed value, and wherein the first step for
causing a transition of the optical disc information recording
means to a recordable state comprises some or all of the following
steps: a step carried out by the laser-emission control means to
emit a laser beam; a servo control step carried out by the servo
control means to control the position of the lens so as to converge
the laser beam on any one of tracks created on the surface of the
optical disc; a step to identify the type of the optical disc on
the basis of a characteristic of the laser beam reflected by the
surface of the optical disc after being radiated by the
laser-emission control means to the surface or a step to identify
the type of the optical disc by reading out information recorded in
advance on the optical disc and demodulating the read-out
information by using the demodulation means; an
optimum-recording-power detection step to find an optimum value of
the emission power of the laser-emission control means, that is, an
optimum power of the laser beam used for recording, by varying the
emission power for each optical disc; a step to search the optical
disc for a recordable position on the optical disc; and a step to
place the lens at the recordable position, and at least one of the
aforementioned steps composing the first step are eliminated from
the second step.
13. The apparatus according to claim 12, further comprising a
storage means, which is capable of retaining data stored therein
even if the power-supply means is cut off, wherein the apparatus is
constituted such that: any one, any combination or all of a result
of identification of the type of the optical disc, the optimum
value of the laser beam used for recording and the recordable
position on the optical disc is stored in the storage means; if an
operation to turn on again the power-supply means is carried out
after an operation carried out to turn off the power-supply means,
one, any combination or all of the result of identification of the
type of the optical disc, the optimum value of the laser beam used
for recording and the recordable position on the optical disc is
read out from the storage means and the second step is carried out
to put the optical disc information recording means in a recordable
state, some of the steps composing the first step can be eliminated
due to availability of one, any combination or all of the result of
identification of the type of the optical disc, the optimum value
of the laser beam used for recording and the recordable position on
the optical disc, which have been read out from the storage
means.
14. The apparatus according to claim 8, further comprising an image
sensing means for sensing an image signal, a display means for
displaying the image signal and an image-signal encoding means for
encoding the image signal wherein the information to be recorded
onto the recording medium is a signal output by the image-signal
encoding means of the image signal.
15. The apparatus according to claim 14, wherein the apparatus is
constituted such that: if the second step is carried out to cause a
transition of the information recording means to a recordable state
after the power-supply means is turned off while the power-supply
means is furnishing power to the image taking means and the display
means, a message indicating that an operation to store information
to be recorded onto the recording medium into the buffer means is
allowed is displayed on the display means at a point of time the
display means starts to operate.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This is a continuation of patent application Ser. No.
10/087,514, filed Feb. 28, 2002, which application claims priority
from Japan Patent Application No. 2001-290411, filed Sep. 25, 2001,
the entire disclosure of which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an apparatus for recording
information onto a recording medium, particularly to operations
from a power-on event of the apparatus to a state in which the
apparatus is capable of starting a step to record information onto
the recording medium.
[0004] 2. Description of the Related Art
[0005] A conventional optical disc drive suffers from
disadvantageous long time for its activation, i.e., from a halt
condition of disc rotation to a steady-state condition of the
rotation. Thus, an information recording apparatus such as the type
for recording an image taking signal onto a recording medium, can
not record the image taking signal onto the recording medium during
some time lapsing after it has turned on, raising a problem that an
image taking chance is missed.
[0006] In order to solve the problem, in an apparatus disclosed in
JP-A No. 93918/1998, the following method is adopted to avoid a
state in which an image taking signal cannot be recorded onto a
recording medium.
[0007] In the apparatus cited above, after the user turns on the
power-supply of the apparatus, a compressed and encoded signal
obtained as a result of compression and encoding steps carried out
on an image taking signal is stored temporarily in a memory means
till a disk drive unit employed in the apparatus enters a state of
being capable of recording information onto a recording medium. The
compressed and encoded signal is referred to hereafter simply as an
image taking signal. Then, at a stage the disk drive unit employed
in the apparatus enters a state of being capable of recording
information onto a recording medium, a recording means employed in
the disc drive unit starts a recording operation while the
operation of storing the following image taking signal into the
memory means is being continued.
[0008] If the amount of information transferred from an image
taking unit employed in the apparatus to the memory means per unit
time is smaller than the amount of information recorded by the
information recording means onto the recording medium per same unit
time, the amount of information stored in the memory means will
decrease gradually. At a stage the amount of information stored in
the memory means becomes zero, the image taking signal is supplied
from the image taking unit directly to the information recording
means employed in the disc drive unit. This state is continued
thereafter till the user enters a command to stop the recording
operation.
[0009] If residual information is left in the memory means at the
time the user enters a command to stop the recording operation, the
recording operation is continued till its completion by recording
all the residual information onto the recording medium.
[0010] As another method, it is also to possible to record an image
taking signal, which has been stored temporarily in the memory
means till a disk drive unit employed in the disc drive unit enters
a state of being capable of recording information, onto a recording
medium later. In this case, a seek operation is carried out to move
a drive head unit to a position on the recording medium. This
position on the recording medium follows a storage area reserved
for the image taking signal stored temporarily in the memory means.
Then, an image taking signal following the image taking signal
stored temporarily in the memory means is supplied to the
information recording means employed in the disc drive unit, taking
precedence of the image taking signal stored temporarily in the
memory means. Finally, after the user enters a command to stop the
recording operation, the image taking signal stored temporarily in
the memory means is recorded into the reserved storage area on the
recording medium.
[0011] The methods described above are each disclosed as a method
to avoid a state of being incapable of recording a signal onto a
recording medium after the power-supply is turned on till the disc
drive unit reaches a predetermined rotation.
SUMMARY OF THE INVENTION
[0012] In the conventional technology described above, the
following points are not specially taken into consideration.
[0013] In the first place, after the user turns on the power-supply
of the apparatus, an image taking signal is stored temporarily in a
memory means till a disk drive unit employed in the apparatus
enters a state of a stable rotation. Then, at a stage the disk
drive unit employed in the apparatus enters a state of a stable
rotation, a recording means employed in the disc drive unit starts
a recording operation and the amount of information stored in the
memory means decreases gradually. At a stage the amount of
information stored in the memory means becomes zero, the image
taking signal is supplied from the image taking unit directly to
the information recording means employed in the disc drive unit. In
order to supply the image taking signal from the image taking unit
directly to the information recording means, a switching means is
required. In addition, a switching timing must be identified. In
order to determine a switching timing, the state of rotation must
be observed all the time in order to make a difficult decision as
to whether to supply the image taking signal from the image taking
unit to the memory means or directly to the information recording
means.
[0014] It is thus a first object of the present invention to
provide an algorithm that can be used with ease to eliminate the
switching means.
[0015] In the second place, the user does not always start a
recording operation when the power-supply is turned on. In the
conventional technology described above, however, neither a method
to clearly identify a state allowing the user to start a recording
operation nor a method to determine a timing to start a recording
operation is specially disclosed. It is thus a second object of the
present invention to provide a method to inform the user of the
fact that a recording operation can be carried out even though
operations to activate components employed in the drive have not
been completed after the user has turned on the power-supply of the
apparatus.
[0016] In the third place, in a step to activate an optical disc
drive, in addition to elements for starting a disc rotation, the
following stepping components are required.
[0017] (1) A laser diode and a laser-emission control circuit. The
laser diode is a component for emitting a laser to be radiated to
the recording medium. The laser-emission control circuit is a
circuit for controlling the output of the laser diode to a
magnitude corresponding to a signal to be recorded onto the
recording medium or a predetermined magnitude.
[0018] (2) An opto-electrical conversion circuit for converting a
beam, which is reflected by the disc recording medium at a quantity
corresponding to pits and recording marks on the disc recording
medium when the laser is emitted at a predetermined output
magnitude, into an electrical signal.
[0019] (3) An object lens, an actuator mechanism and a control
circuit of the actuator mechanism. The object lens is a component
for converging the laser beam. The actuator mechanism is a
component for moving the object lens in the same direction as the
optical axis in order to focus the laser beam on the surface of the
disc recording medium in the so-called focusing operation and for
moving the object lens in the radial direction of the recording
medium in order to place the spot of the focused laser beam on a
desired track of the disc recording medium in the so-called tracing
(or tracking) operation.
[0020] (4) A spindle motor, a control circuit of the spindle motor,
a base, a slider mechanism and a control circuit of the slider
mechanism. The spindle motor is a component for rotating the disc
recording medium. The base is a component on which at least the
object lens and the actuator mechanism are mounted. The slider
mechanism is a component for moving the base. The base and the
slider mechanism are required because, with only the actuator
mechanism for moving the object lens in a tracking operation, all
tracks cannot be accessed.
[0021] The circuits including the control circuits cited above need
to be operated sequentially as follows.
[0022] In order to record a signal onto an optical disc or
reproduce a signal from an optical disc, the actuator mechanism
described in section (3) and the slider mechanism described in
section (4) are controlled by operating their respective control
circuits to focus the laser beam on the surface of the optical disc
and to position the spot of the focused laser beam on a desired
track of the disc. Then, the laser-emission control circuit
described in section (1) as well as the opto-electrical conversion
circuit described in section (2) are operated and, if necessary,
the control circuit described in section (3) is again operated
properly in order to achieve a state allowing a recording or
reproduction operation to be carried out for the first time.
[0023] However, the optical disc drive is easily affected by
variations from disc to disc and variations from apparatus to
apparatus. In consequence, it is not easy to execute the proper
control described above. In order to solve this problem, learning
control has been much proposed. The learning control is executed to
find a control value to be set in each of the control circuits
(including mainly the actuator control circuit and the
laser-emission control circuit) each time the control value is
required.
[0024] In particular, it takes relatively long times in many cases
to execute the learning control of the laser-emission control
system to learn a recording optical power and learn an emission
timing of the recording emission power. The emission timing is
determined to adjust the so-called time-axis phase, which is
referred to simply as a recording phase for the sake of
simplicity.
[0025] In addition, the mechanisms described above and the control
circuit system must be capable of handling a disc of another type
in some cases. In such cases, the type of a disc is recognized from
a variety of physical quantities such as amplitudes of various
control feedback signals and amplitudes of information reproduction
signals. It takes a relatively long time to identify the type of a
disc from such physical quantities. Examples of the control
feedback signals and the information reproduction signals are an
error signal of a beam reflected by the disc and used in the
focusing control or the tracking control and a signal proportional
to a rotational speed of the disc. The signal proportional to a
rotational speed is used in control of the disc rotation and
embedded on tracks of the disc in advance.
[0026] In order to correctly identify the type of the recording
medium, it is necessary to read out information on the recording
medium and information on a physical format for each medium type
from the recording medium. The information on the recording medium
and the information on a physical format for each medium type have
been recorded on the recording medium in advance.
[0027] It is also necessary to read out information on medium
management from the recording medium. The information on medium
management is information on management of defects in the case of a
rewritable disc or information on locations to which additional
data can be written in the case of an addable-type disc. It also
takes a relatively long time to read out these pieces of
information on management. In particular, in the case of an
addable-type disc, it is necessary to verify that a location at
which data was recorded last as described by the medium-management
information read out from the recording medium indeed matches a
location preceding a location to which additional data can be
written. That is to say, it takes a very long time to carry out a
step for searching the disc recording medium for a location at
which data was actually recorded last.
[0028] In accordance with specifications, in an information
recording apparatus for recording information onto a disc recording
medium, in addition to the building-up step of the rotation of the
disc to reach a steady state, there is a number of much-time
consuming operations that need to be completed before a recordable
state of the disc is achieved after the power-supply is turned
on.
[0029] That is to say, in the case of the conventional described
above, there is specially no description of a technique to avoid a
period of time during which data cannot be recorded onto the disc
recording medium for the reasons described above. It is thus a
third object of the present invention to avoid a period of time
during which data cannot be recorded onto the disc recording medium
for the reasons other than the building-up step of the rotation of
the disc to reach a steady state.
[0030] In order to solve the problems described above, the present
invention provides the following means.
[0031] In the first place, in order to achieve the first object of
the present invention, the present invention provides a
configuration in which, instead of observing a condition for
switching from an unrecordable state to a recordable state, an
operation to supply information stored in a memory means to a
recording means employed in a drive is started at a stage the
amount of information stored in the memory means exceeds a
predetermined quantity.
[0032] In the second place, in order to achieve the second object
of the present invention, the present invention provides a display
means allowing the user to recognize a startable recording
state.
[0033] In the third place, in order to achieve the third object of
the present invention, first of all, the present invention provides
a means for monitoring operations to mount and dismount the disc
recording medium on and from the information recording apparatus.
If the means clearly verifies no replacement of the disc recording
medium mounted on the drive, some or all of the steps that consume
much time, causing the problems described above can be eliminated.
The steps include the step to recognize the type of the disc
recording medium, the step to read out the information on medium
management from the disc recording medium or search the disc
recording medium for a location at which user data was actually
recorded last in the case of an addable-type disc recording medium
and the step to learn a recording power and a recording phase. As a
result, it is possible to considerably reduce the length of a
period of time during which the information recording means
employed in the drive is put in an unrecordable state after the
power-supply is turned on.
[0034] Specifically, the present invention provides a configuration
in which, if the disc recording medium is inserted and the
power-supply is turned on for the first time, the user is informed
of the fact that an operation to record data onto the disc
recording medium can be started after the information recording
means for carrying out the activation steps described above in
accordance with a first stepping procedure enters a recordable
state. In the same configuration, if the power-supply is turned on
for the second or subsequent time, the user is informed of the fact
that an operation to record data onto the disc recording medium can
be started after the information recording means for completes
operations in accordance with a second stepping procedure
eliminating some time-consuming ones of the activation steps
described above prior to a recordable state.
[0035] As described above, the present invention exhibits an effect
that a simple algorithm is capable of avoiding an unrecordable
state due to, among other causes, the disc rotation's buildup step
with a duration equal to a relatively fixed period of stepping
time.
[0036] In addition, a time-consuming step, which is to be carried
out after the power-supply is turned on, can be eliminated during
an activation step following a second or subsequent power-on
operation but not during an activation step following the first
power-on operation in order to avoid an unrecordable state that
would take a long time.
[0037] Furthermore, by informing the user that an operation to
record data onto the disc recording medium can be started, the user
is capable of easily identifying a timing to start the operation to
record data onto the disc recording medium.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] FIG. 1 is an explanatory block diagram showing the
configuration of an embodiment of the present invention;
[0039] FIG. 2 shows first timing charts used for explaining
operations carried out by an embodiment of the present
invention;
[0040] FIG. 3 shows second timing charts used for explaining
operations carried out by an embodiment of the present invention;
and
[0041] FIG. 4 shows an explanatory flowchart representing a load
step carried out by a drive controller 12 provided by an embodiment
of the present invention.
PREFERRED EMBODIMENTS OF THE INVENTION
[0042] Preferred embodiments of the invention are explained by
referring to FIGS. 1 to 4 as follows. An embodiment of the
invention implements a video camera for recording an image signal
onto an optical disc. The image signal is a signal obtained as a
result of an image taking operation carried out by an image taking
unit employed in the video camera. The description begins with an
explanation of operations of components and a configuration
comprising the components with reference to FIG. 1.
[0043] First of all, implementation of a means for mounting and
demounting a disc on and from a disc drive unit is explained.
[0044] Reference numeral 1 denotes a cover of a case for
accommodating an optical disc 3. Reference numeral 2 denotes a
switch for detecting an opened or closed state of the cover 1. The
cover switch 2 is connected to a system controller 22. The system
controller 22 is a microstepor powered by a main battery 29 through
a main power-supply switch 31, a power-supply series regulator
circuit 33 and a power-supply changeover switch 32 or by a backup
battery 30 through the power-supply series regulator circuit 33 and
the power-supply changeover switch 32. Thus, even if power-supply
switch 31 is turned off, cutting off the power supplied by the main
battery 29 to the system controller 22, an operation carried out by
the system controller 22 is continued, enabling the system
controller 22 to receive a signal indicating the opened/closed
state of the cover 1 from the cover switch 2. As a result, the
system controller 22 is capable of recognizing the possibility that
the optical disc 3 has been mounted or demounted on or from the
case for accommodating an optical disc 3.
[0045] Next, a control means for controlling a spindle motor is
explained.
[0046] Reference numeral 4 denotes a spindle motor for driving the
rotation of the optical disc 3. The spindle motor 4 outputs a
signal proportional to its own rotational speed to a spindle motor
control circuit 5. The spindle motor control circuit 5 measures a
period and a phase of the signal proportional to the rotational
speed and compares the measured period and the measured phase with
a target period and a target phase respectively. The spindle motor
control circuit 5 then outputs speed-error signals representing a
difference between the measured period and the target period as
well as a difference between the measured phase and the target
phase to the spindle motor 4 in order to control the spindle motor
4.
[0047] In addition, an opto-electrical conversion circuit 16
detects a frequency signal included in a beam reflected by the
optical disc 3 and supplies the frequency signal to the spindle
motor control circuit 5. The frequency signal is proportional to
the rotational speed of the optical disc 3. The frequency signal is
embedded in advance in tracks on the optical disc 3 as a format.
The spindle motor control circuit 5 generates a control signal and
outputs the control signal to the spindle motor 4 in order to
control the rotational speed of the spindle motor 4 to a
predetermined rotational speed. To put it in more detail, the
spindle motor control circuit 5 adjusts the rotational speed of the
spindle motor 4 so that the frequency signal read out from the
tracks of the optical disc 3 approaches a value corresponding to
the predetermined rotational speed as much as possible.
[0048] Next, the spindle motor control circuit 5 for controlling
the spindle motor 4 is explained.
[0049] Reference numeral 9 denotes a slider mechanism on which an
object lens 7, an actuator mechanism 8, a laser diode 14 and the
opto-electrical conversion circuit 16 are mounted. Reference
numeral 10 denotes a slider motor. The slider motor 10 is typically
a micro-step motor. Reference numeral 11 denotes a slider-motor
control circuit for receiving a set value from a drive controller
12 and outputting a two-phase rectangular or sinusoidal driving
signal to the slider motor 10. The frequency of this driving signal
determines a distance by which the slider mechanism 9 is to be
moved.
[0050] Next, an actuator control means for controlling the actuator
mechanism 8 is explained.
[0051] The actuator mechanism 8 is a component for controlling the
object lens 7. To put in detail, the actuator mechanism 8 moves the
object lens 7 in the direction of the optical axis and the radial
direction of the optical disc 3 in accordance with a control signal
generated by an actuator-servo control circuit 17. The
actuator-servo control circuit 17 generates focusing and tracking
error signals on the basis of an electrical signal obtained as a
result of an opto-electrical step carried out by the
opto-electrical conversion circuit 16 on a beam reflected by the
optical disc 3. The actuator-servo control circuit 17 then outputs
the control signal to the actuator mechanism 8 after carrying out
proper control compensation.
[0052] Next, an information recording and reproduction means for
recording and reproducing a signal onto and from the optical disc 3
is explained. Reference numeral 14 denotes a laser diode. A laser
beam emitted by the laser diode 14 hits the object lens 7. The
output of the laser diode 14 is controlled by a laser driver 15.
The laser driver 15 controls the laser beam emitted by the laser
diode 14 to a predetermined output value in a reproduction
operation. In a recording operation, on the other hand, the laser
driver 15 controls the laser diode 14 to emit a laser beam
corresponding to a modulated signal as much as possible. The
modulated signal is received from a modulation and demodulation
circuit 18. The laser driver 15 is switched from a recording mode
to a reproduction mode and vice versa by a driver controller
12.
[0053] A beam reflected by the surface of the optical disc 3 is
supplied the opto-electrical conversion circuit 16, being converted
into an electrical signal, which is then fed to the modulation and
demodulation circuit 18. The modulation and demodulation circuit 18
demodulates the electrical signal. The modulation and demodulation
circuit 18 is also switched from a modulation mode to a
demodulation mode and vice versa by the driver controller 12.
[0054] By referring to FIG. 2, the following description explains
operations carried out by an apparatus at the upper level of the
drive unit shown in FIG. 1.
[0055] The description begins with an explanation of a state in
which the power-supply switch 31 is put at an OFF position. With
the power-supply switch 31 put at an OFF position, the power-supply
changeover switch 32 is put at a position of selecting the backup
battery 30. In this state, power is supplied by the backup battery
30 to the system controller 22 by way of the power-supply series
regulator circuit 33 so that the system controller 22 is capable of
monitoring the cover switch 2 and a power-supply on/off command
switch 6.
[0056] Assume that, in this state, the user enters a command to
turn on the power by operating the power-supply on/off command
switch 6. In this case, the system controller 22 turns on the
power-supply switch 31. When the power-supply switch 31 is turned
on, the power-supply changeover switch 32 is switched by a
switching signal to a position of selecting the main battery 29.
The switching signal is also used by a reset-signal generation
circuit 41 as a base for switching the system controller 22 from a
low power consumption mode in which power is supplied from the
backup battery 30 to a normal mode. Time charts shown in FIG. 2
indicate a timing with which the power-supply switch 31 is turned
on by a power-on command from the system controller 22.
[0057] In this state, the system controller 22 also activates a
power-supply circuit 26. When activated, the power-supply circuit
26 generates a power-supply signal 36 supplied to a variety of
components and a reset signal 35 supplied to the driver controller
12. Receiving the reset signal 35, the driver controller 12 enters
a state of waiting for a command to be transmitted from the upper
level unit by way of a packet interface circuit 19.
[0058] If the cover switch 2 is changed from an opened state to a
closed state while the power-supply switch 31 is at the OFF
position, the system controller 22 informs the memory controller 21
of the change in state.
[0059] Informed of the change in state, through the packet
interface circuit 19, the memory controller 21 issues a request to
the driver controller 12 to carry out an activation step according
to a first activation method at a point of time indicated by an
arrow Load 1 in FIG. 2. Receiving the request, the driver
controller 12 activates a power-supply switch 40 in the drive unit
to start an operation to supply power to a variety of components
employed in the drive unit during a period of time indicated by
notation Load in FIG. 2.
[0060] An example of this activation step is represented by a
flowchart (1) of FIG. 4. As shown in the figure, the flowchart
begins with a step s101 at which the actuator-servo control circuit
17 is operated to drive the actuator mechanism 8 to carry out a
lens-down step (s101). In the lens-down step, the object lens 7 is
moved away from the optical disc 3. Then, at the next step s102,
the laser driver 15 is operated to drive the laser diode 14 to emit
a laser beam at a predetermined emission power. In this way, the
laser beam is radiated all of a sudden to the surface of the
optical disc 3 without being focused.
[0061] Subsequently, at the next step s103, the driver controller
12 operates the actuator-servo control circuit 17 to drive the
object lens 7 up and down in the direction of the optical axis. A
beam reflected by the optical disc 3 can thus be obtained through
the opto-electrical conversion circuit 16 when the object lens 7
passes through an area around the focus point. A first stage
classification step based on the amplitude of the reflected beam
and other information is carried out.
[0062] Then, at the next step s104, the driver controller 12
operates the spindle motor control circuit 5 to start rotating the
spindle motor 4. At this stage, the spindle motor control circuit 5
controls the spindle motor 4 by using a signal proportional to the
rotational frequency of the spindle motor 4. The signal is
generated by the spindle motor 4 itself.
[0063] Subsequently, at the next step s105, the driver controller
12 again operates the actuator-servo control circuit 17 to drive
the actuator mechanism 8 to move the object lens 7 up and down in
order to focus the laser beam on the surface of the optical disc
3.
[0064] As the laser beam gets focused on the surface of the optical
disc 3, it is possible to observe a track-crossing signal
indicating that the laser beam crosses a track created on the
optical disc 3 due to eccentricity of the optical disc 3 itself of
eccentricity existing in the spindle motor 4. Then, at the next
step s106, the driver controller 12 further carries out a second
step to classify the types of the optical disc 3 on the basis of
information including the amplitude of the track-crossing signal
supplied to the actuator-servo control circuit 17 from the
opto-electrical conversion circuit 16. It is thus possible to
roughly identify the physical type of the optical disc 3.
[0065] Subsequently, at the next step s107, the driver controller
12 operates the actuator-servo control circuit 17 to make a track
indicated by the track-crossing signal follow the laser beam.
[0066] At this stage, preparations to read out information from the
track on the optical disc 3 have been completed. Then, at the next
step s108, the driver controller 12 reads out recording-medium
information recorded in advance on a specific track prescribed by
format specifications of the optical disc 3. The information on the
recording medium theoretically confirms the type of the optical
disc 3.
[0067] Subsequently, at the next step s109, the driver controller
12 reads out information on medium management. In the case of a
rewritable disc, the information on medium management includes
defect management information indicating a location on the surface
of the disc at which a defect exists and indicates a spare
recording location allocated as a substitute for the defective
location. In order to assure safety, the information on defect
management is generally copied and the information and its copies
are recorded at a plurality of recording locations on the surface
of the optical disc 3. In order to grasp the most reliable piece of
information on defect management among the pieces of information on
defect management, all the pieces of information on defect
management are read out to determine the most reliable piece of
information on defect management in case it is quite within the
bounds of possibility that the optical disc 3 is replaced.
[0068] In the case of an addable-type disc, on the other hand, the
information on medium management includes information indicating a
location on the surface of the optical disc 3 at which data was
recorded last. In the case of an addable-type disc, it is necessary
to verify that the location at which data was recorded last indeed
matches a location preceding a location to which additional data
can be actually written. Thus, at the next step s110, the driver
controller 12 searches the optical disc 3 for the location at which
additional data can be actually written on the basis of the
location at which data was recorded last.
[0069] What is described above is a first activation method. For
the sake of convenience, a period of time indicated by notation
Load in FIG. 2 is divided into sub-periods denoted by Setup, Judge
and Read. The Setup sub-period of time is a sub-period during which
the spindle motor 4 and the actuator mechanism 8 are controlled.
The Judge sub-period of time is a sub-period during which the type
of the optical disc 3 is identified. The Read sub-period of time is
a sub-period during which the information on the medium or the
information on the medium management is read out from the optical
disc 3 or the optical disc 3 is searched for a location to which
additional data can be added in the case of an addable-type
disc.
[0070] Let us go back to the description of a case, in which the
cover 1 was opened before the power-supply was turned on, with
reference to FIGS. 1 and 2.
[0071] While the activation step is being carried out by the driver
controller 12 in accordance with the first activation method, the
system controller 22 requests the memory controller 21 to receive
no request to start a recording operation from the user. In order
to inform the user that no request to start a recording operation
is accepted, the memory controller 21 displays a message, which
indicates that a step to recognize the type of the optical disc 3
is going on, on a liquid-crystal monitor 25, by driving a
compression and decompression circuit 24 to superpose the message
on the image taking signal.
[0072] As the memory controller 21 is notified of the fact that the
activation step carried out by the driver controller 12 in
accordance with the first activation method has been completed
through the packet interface circuit 19, the memory controller 21
passes on the notification to the system controller 22, and
displays a message, which indicates that a recordable state has
been reached, to the user on the liquid-crystal monitor 25 in the
same way as the message, which indicates that a step to recognize
the type of the optical disc 3 is going on, during a period
referred to as a Rec Pause period in FIG. 2.
[0073] Receiving the notification, the system controller 22 starts
an operation to monitor a button switch 27 to be operated by the
user to enter a command to start or stop a recording operation.
[0074] If the system controller 22 does not detect an operation
carried out by the user to enter a command to start a recording
operation, the memory controller 21 issues a request to the driver
controller 12 to stop operations in order to save energy. Receiving
the request, the driver controller 12 stops the operations of the
components and turns off the power-supply switch 40 in order to
avoid the waste of power.
[0075] In this state, when the user operates the button switch 27
to enter a command to start a recording operation at a point of
time indicated by an arrow Rec Start in FIG. 2, the system
controller 22 accepts the command and passes on the command to the
memory controller 21.
[0076] The memory controller 21 passes on the command to start a
recording operation to the driver controller 12 as indicated by an
arrow Write shown in FIG. 2. At the same time, a signal output by
the image taking circuit 23 is encoded by the compression and
decompression circuit 24 and an operation to start storing
information in a memory circuit 20 is carried out. In addition, a
message indicating that the recording operation has been started is
displayed to the user on the liquid-crystal monitor 25 in a period
called Display during Rec in FIG. 2.
[0077] Receiving the command to start a recording operation, the
driver controller 12 turns on the power-supply switch 40 to resume
the operation of the stopped spindle motor 4, the emission of a
laser beam and the control of the actuator. Since the step of
acquiring information for recognizing the type of the optical disc
3 and information on medium management as well as the step to
verify a location on an addable-type disc to which data is to be
added have already been completed, the activation step merely to
resume the operation of the mechanism control system and to resume
the emission of the laser beam can be completed in a relatively
short period of time.
[0078] Since learning steps to find optimum values of the recording
power supplied to the recording medium and the recording phase have
not been carried out, however, the learning steps to find optimum
values of at least either the recording power or the recording
phase or both the recording power and the recording phase need to
be carried out during the step of storing the image taking signal
in the memory circuit 20.
[0079] The learning steps to find optimum values of the recording
power and the recording phase are carried out in a trial-and-error
manner to evaluate a condition, in which data is written onto the
optical disc 3, by actually storing data onto the optical disc 3
while changing parameters for adjusting the recording power and the
recording phase from time to time.
[0080] Thus, in the case of a rewritable disc, since an area for
storing data in the trial-and-error step can be used repeatedly,
the learning steps to find optimum values of the recording power
and the recording phase can be carried out as part of the
first-activation-method-based activation step following the
power-on operation as described earlier.
[0081] In the case of an addable-type disc, on the other hand, an
area for storing data in the trial-and-error step cannot be used
repeatedly. Thus, there is a limit on the number of times the
trial-and-error step can be carried out on a disc. For this reason,
the leaning steps to find optimum values of the recording power and
the recording phase are not carried out as part of the
first-activation-method-based activation step following the
power-on operation. Instead, the learning steps are carried out
when there is actually a request for such steps.
[0082] Even if the learning steps are completed, the memory
controller 21 does not start a recording operation immediately.
Instead, the memory controller 21 starts a recording operation
after the amount of information of the image taking signal stored
in the memory circuit 20 exceeds a first predetermined
quantity.
[0083] As the recording operation is started, the amount of
information stored in the memory circuit 20 gradually decreases.
When the amount of information stored in the memory circuit 20
decreases to a value smaller than a second predetermined value, the
memory controller 21 stops the recording operation. In addition, in
order to reduce the amount of power consumed by the drive unit till
the recording operation is resumed, the driver controller 12 is
requested to stop operations. As requested, the driver controller
12 stops operations of the components and turns off the
power-supply switch 40 in order to decrease power consumption.
[0084] With the recording operation stopped, the amount of
information stored in the memory circuit 20 again increases. As the
amount of information stored in the memory circuit 20 reaches a
value slightly smaller than the first predetermined quantity, the
memory controller 21 makes a request for the activation of the
driver controller 12. Receiving the request, the driver controller
12 again turns on the power-supply switch 40 to operate the spindle
motor control circuit 5, the laser driver 15 and the actuator-servo
control circuit 17. This time, since the learning steps of the
recording power and the recording phase have been completed, the
recordable state can be reached in a short period of time.
[0085] The intermittent operations described above are carried out
repeatedly till the user operates the button switch 27. As the user
operates the button switch 27 to enter a command to stop the
recording operation at a point of time indicated by an arrow Rec
Stop in FIG. 2, the system controller 22 detects this command and
informs the memory controller 21 that the recording operation is to
be stopped. Receiving this notification, the memory controller 21
stops an operation to supply the image taking signal to the memory
circuit 20 thereafter and changes the display appearing on the
liquid-crystal monitor 25 to a state of being ready to start a
recording operation. In addition, the memory controller 21 issues a
request to the driver controller 12 to stop operations after
waiting for all residual information left in the memory circuit 20
to be recorded by the drive unit onto the optical disc 3. Receiving
this request, the driver controller 12 stops operations of
components and turns off the power-supply switch 40 in order to
decrease power consumption.
[0086] In this state, when the user operates the button switch 27
to enter a command to start a recording operation at a point of
time not shown in FIG. 2, the system controller 22 accepts the
command and passes on the command to the memory controller 21.
Receiving the command, the memory controller 21 starts a recording
operation to store the image taking signal in the memory circuit
20. Thereafter, the intermittent operations are carried out
repeatedly in the same way as described above.
[0087] When the user operates the power-supply on/off command
switch 6 with the recording operation stopped to make a request to
cut off power supplied to the whole apparatus at a point of time
indicated by arrow Power Off in FIG. 2, on the other hand, the
system controller 22 detects this request and passes on this
request to the memory controller 21. The memory controller 21 also
informs the driver controller 12 that the power supplied to the
whole apparatus is to be cut off.
[0088] Informed that the power supplied to the whole apparatus is
to be cut off, the driver controller 12 saves the type of the disc
recording medium currently mounted on the disc drive as well as the
learning values of the recording power and the recording phase in a
non-volatile memory circuit 13. In the case of an addable-type
disc, the driver controller 12 also saves the information on
matching between the last recording location included in the
information on medium management and an actual recording location
in the non-volatile memory circuit 13. In the case of a rewritable
disc, on the other hand, the driver controller 12 also saves data
such as information on validity of pieces of information on defect
management recorded at a plurality of locations, that is,
information indicating which pieces of information on defect
management are valid, into the non-volatile memory circuit 13.
After the step to save the information in the non-volatile memory
circuit 13 is completed, the driver controller 12 notifies the
memory controller 21 of the completion. Receiving this
notification, the memory controller 21 passes on the notification
to the system controller 22. Informed that the step to save the
information in the non-volatile memory circuit 13 has been
completed, the system controller 22 stops the operation of the
power-supply circuit 26 in order to terminate a step to supply
power to the drive unit and the image taking block. Thereafter, the
system controller 22 merely continues execution of a program for
monitoring the power-supply on/off command switch 6 and the cover
switch 2, turning off the power-supply switch 31 in order to
receive power-only from the backup battery 30 in a power-saving
operation.
[0089] The above description explains the operations, which are
carried out when the user enters a command to turn on the
power-supply to furnish power to the whole apparatus if the cover 1
has been opened and closed with the power-supply cut off,
indicating that it is quite within the bounds of possibility that
the optical disc 3 has been replaced with another one. Next, by
referring to FIGS. 1, 3 and 4 (2), the following description
explains operations, which are carried out when the user enters a
command to turn on the power-supply furnishing power to the whole
apparatus if an operation to open and close the cover 1 has not
been recognized at all with the power-supply cut off, indicating
that it is out of the bounds of possibility that the optical disc 3
has been replaced with another one.
[0090] First of all, when the user operates the power-supply on/off
command switch 6 to enter a command to turn on the power-supply,
the system controller 22 detects this operation. At that time, the
system controller 22 switches the source supplying power to itself
from the backup battery 30 to the main battery 29. In addition, the
system controller 22 operates the power-supply circuit 26 to carry
out steps including an operation to supply power to the drive block
and the image taking block through a power-supply line 36 in the
same way as what has been described earlier by referring to FIG.
2.
[0091] The system controller 22 notifies the memory controller 21
that an operation to open and close the cover 1 has not been
recognized during a period of time in which the power-supply is cut
off. Receiving this notification, the memory controller 21 issues a
command to carry out an activation operation according to a second
activation method to the driver controller 12 at a point of time
coinciding with an arrow Load 2 shown in FIG. 3.
[0092] Receiving the command, the driver controller 12 starts
activation of the drive unit in a second-activation-method-based
activation step represented by a flowchart shown in FIG. 4 (2).
Details of the flowchart are explained as follows.
[0093] As shown in the figure, the flowchart begins with a step
s201 at which information is read out from the non-volatile memory
circuit 13. As described in the explanation of the operations with
reference to FIG. 2, the information read out from the non-volatile
memory circuit 13 includes the type of the disc recording medium
currently mounted on the disc drive as well as the learning values
of the recording power and the recording phase. In the case of an
addable-type disc, the information read out from the non-volatile
memory circuit 13 also includes the inform on matching between the
last recording location included in the information on medium
management and an actual recording location. In the case of a
rewritable disc, on the other hand, the information read out from
the non-volatile memory circuit 13 also includes data such as
information on validity of information on defect management
recorded at a plurality of locations, that is, information
indicating which pieces of information on defect management are
valid. The flow of the stepping then goes on to the next step s202
to form a judgment as to whether or not all pieces of information
have been gathered and there will be no problems even if a
recording operation is started. If all pieces of information have
been gathered and there will be no problems even if a recording
operation is started, the flow of the stepping goes on to a step
s203 at which the memory controller 21 is notified that all pieces
of information have been gathered and there will be no problems
even if a recording operation is started. Receiving this
notification, the memory controller 21 displays a message
indicating that a recording operation can be started on the
liquid-crystal monitor 25 during a period of time indicated by Rec
Pause in FIG. 3.
[0094] Refer back to the flowchart shown in FIG. 4 (2). Since the
type of the optical disc 3 has been recognized from the information
read out from the non-volatile memory circuit 13, the driver
controller 12 operates the spindle motor control circuit 5, the
laser driver 15 and the actuator-servo control circuit 17 in an
order they are enumerated here at steps s204, s205, s206, s207 and
s208 in order to transit to a state in which information can be
read out from the optical disc 3. If all information on the medium
has been stored in the non-volatile memory circuit 13, it is not
necessary to carry out an operation to read out information from
the optical disc 3. Since some information exists in the optical
disc 3, however, in this embodiment, the information is read out
from the optical disc 3 at the next step s209.
[0095] Then, at the next step s210, one valid piece of information
on medium management is read out from the optical disc 3 if the
optical disc 3 is a rewritable disc. Since information indicating
which pieces of information on defect management are valid has been
stored in the non-volatile memory circuit 13, however, the
operation of the step s210 can be completed in a short period of
time.
[0096] In the case of an addable-type disc, on the other hand, the
information stored in the non-volatile memory circuit 13 also
includes the inform on matching between the last recording location
included in the information on medium management and an actual
recording location. Thus, the search step can be eliminated. As a
result, the operation of the step s210 can also be completed in a
short period of time as well.
[0097] As described above, for a disc experiencing an activation
step according to the first activation method in the past, the time
it takes to carry out an activation step can be shortened
substantially. Thus, it is possible to display a message indicating
that the resumption of a recording step is allowable on the
liquid-crystal monitor 25 during a period of time indicated by Rec
Pause in FIG. 3. That is to say, if the driver controller 12 is
requested to implement the second activation method, the memory
controller 21 informs the user that the resumption of a recording
step is allowable without waiting for a report of activation-step
completion to be issued by the driver controller 12 as long as
there is no condition for objections in data stored in the
non-volatile memory circuit 13 (for example, as long as the user
did not make a request for an operation to cut off power before the
type of the recording medium could be identified when the drive
unit was activated by adoption of the first activation method).
[0098] Refer back to the time charts shown in FIG. 3. If the user
operates the button switch 27 to enter a command to start a
recording operation while the driver controller 12 is activating
the drive unit by adoption of the second activation method, the
system controller 22 detects this command and passes on the command
to the memory controller 21. Receiving this command, the memory
controller 21 starts an operation to store the image taking signal
in the memory circuit 20. Since the activation step according to
the second activation method can be completed in a relatively short
period of time as described above, the activation step according to
the second activation method can be completed before the amount of
the image taking signal stored in the memory circuit 20 exceeds the
first predetermined quantity. Thus, the memory controller 21 may
start an actual recording operation as soon as the amount of the
image taking signal stored in the memory circuit 20 exceeds the
first predetermined quantity in the same way as that explained
earlier by referring to the time charts shown in FIG. 2 without
taking the operation of the driver controller 12 into
consideration.
[0099] Thereafter, the amount of information stored in the memory
circuit 20 gradually decreases and intermittent recording
operations are carried out repeatedly in the same way as that
explained earlier by referring to the time charts shown in FIG. 2.
In addition, if the user enters a command to stop the recording
operation to be followed by a command to cut off power supplied to
the whole apparatus, operations are carried out also in the same
way as that explained earlier by referring to the time charts shown
in FIG. 2.
[0100] Thereafter, if the optical disc 3 is not replaced with
another one while no power is being supplied to the whole
apparatus, a subsequent step to transit to a recordable state at
power-on is carried out by adoption of the second activation method
described above. Thus, the user is allowed to enter a command to
start a recording operation without the need to wait for the
activation step to be completed.
* * * * *